WO2018108142A1 - Modular power system - Google Patents

Abstract

A modular power system comprises a primary controller (90), N local controllers (91), and N power units (70). The primary controller is configured to output a primary control signal. Each local controller is configured to receive the primary control signal to output at least one local control signal. The N power units (70) correspond to the N local controllers in a one-to-one manner. Each power unit comprises a first end (X₁) and a second end (X₂). A second end of each power unit is connected to a first end of an adjacent power unit. Each power unit is configured to comprise M power converters (701). Each power converter is configured to operate according to the local control signal outputted by the corresponding local controller, and local control signals for controlling power semiconductor switches at the same position among at least two power converters among the M power converters to be switched on and switched off at the same time are a same local control signal. The modular power system can simplify the structure, can reduce costs and can improve reliability.

Description

Modular power system Technical field

The present invention relates to the field of power electronics, and in particular to a modular power system.

Background technique

Currently, at some higher voltage levels (such as above 10kV) applications, such as Static Var Generator (SVG), Medium Variable-frequency Drive (MVD), and Light HVDC Transmission System ( High Voltage Direct Current Transmission Light (HVDC-Light), etc., due to the high system voltage level, limited by the withstand voltage level and cost of the semiconductor device, the circuit topology of the power unit cascade is usually adopted.

The traditional power unit cascaded topology requires a set of optical fibers, auxiliary power supplies, and local controllers for each power unit, ie, the power converter. This power unit cascaded topology increases with the increase of the voltage level, and the number of power units that need to be cascaded increases, resulting in an increase in the number of optical fibers, auxiliary power supplies, and local controllers. The design is complex, costly, and reduces its reliability.

1 is a schematic structural view of a three-phase SVG system in the prior art. 2 is a schematic diagram of a more specific three-phase SVG system in the prior art. The SVG system of Figures 1 and 2 includes three phase circuits in which the power cells in each phase are connected in cascade.

As shown in FIG. 1, each phase circuit of the SVG system is formed by cascading a plurality of power units 1. The term "cascade" is a common knowledge in the art, i.e., each power cell comprises a first end and a second end T ₁ T _2, wherein two adjacent power cell a second terminal T ₂ and the other The first end T _{1 of one is} connected. Each phase circuit of the first power units through a first end of the filter L T ₁ are respectively connected to three-phase network U _A, U _B and U _C on the three-phase line, the last one power unit for each phase circuit The second ends are connected to each other.

As shown in FIG. 2, each phase circuit of the SVG system is formed by cascading eight power units P ₁ to P ₈ . Each power unit includes a first end and a second end as shown in Figure 1, wherein a second end of one of the adjacent two power units is coupled to the first end of the other. For example, the second end of the power unit P ₁ and P power unit ₂ is connected to a first end, a second end of the power unit P and the power unit P is connected to a first end of the _{2 3,} and so on, a second power unit P ₇ The terminal is connected to the first end of the power unit P ₈ . The first end of the three power units P ₁ in the three-phase circuit is connected to the U _A , U _B and U _C phases of the three-phase power grid G through a filter circuit (composed of the inductor L, the resistor R and the capacitor C), wherein the three phases The U _A , U _B and U _C of the grid G are connected to the load R _load . The second ends of the three power units P ₈ in the three-phase circuit are connected to each other. Four power switching devices 2 are included in each power unit. Each power switching device 2 consists of a power semiconductor switch S and an anti-parallel body diode or external diode D. The collector of the power semiconductor switch S is connected to the cathode of the diode D, and the emitter of the power semiconductor switch S is connected to the anode of the diode D. Since the power semiconductor switch S and an anti-parallel body diode or external diode D are generally used as a whole, for the sake of brevity, the anti-parallel body diode or external diode D will not be separately mentioned in the following description. .

The power unit 1 shown in FIG. 1 may be a full bridge (H bridge) circuit, or may be other circuit topologies such as a half bridge circuit, a rectification-inverter circuit, and the like. 3 is a schematic diagram of an H-bridge circuit (topology) in the prior art. For example, a power unit circuit, for example an H-bridge, H-bridge circuit shown in Figure 3, comprises a power semiconductor switch S ₁ is to S ₄ and the DC bus capacitor C _B. The first end of the power semiconductor switch S ₁ is connected to the positive terminal of the DC bus capacitor C _B and the first terminal of the power semiconductor switch S ₃ . A second end of the power semiconductor switch S ₁ is coupled to the first end of the power semiconductor switch S ₄ . The second end of the power semiconductor switch S ₄ is connected to the negative terminal of the DC bus capacitor C _B and the second terminal of the power semiconductor switch S ₂ . A second terminal of the power semiconductor switch _{S. 3} is connected to a first terminal of the power semiconductor switch S _2. The second end of the power semiconductor switch S ₁ serves as a first output of the H-bridge circuit, that is, the first end T _{1 of the} power unit 1, and the second end of the power semiconductor switch S ₃ serves as a second output of the H-bridge circuit. That is, the second end T _{2 of the} power unit 1.

4 is a schematic diagram of a single phase SVG in the prior art. As shown in FIG. 4, the single-phase SVG includes a charging portion 3, a power portion 4, and a control portion 5. The single phase SVG also includes a plurality of power units 40, each of which includes a first end and a second end as shown in FIG. 1, a first end of one of the adjacent two power units 40 and another The second end is connected. Figure 4 is a conventional cascaded solution for a 25kV single phase SVG. The SVG is cascaded by a plurality of power units to form a phase that is connected to the grid via filters and contactors. Each power unit 40 of the SVG typically employs an H-bridge circuit. The topology of the H-bridge circuit is shown in Figure 3 and will not be described here. Each power unit 40 of the SVG system further includes a DC bus capacitor C _B whose connection relationship is as shown in FIG. 4 , wherein the charging portion 3 is used to precharge the DC bus capacitor C _B , and the control portion 5 is used to control the power. Part 4 runs.

As can be seen from FIG. 4, in the conventional cascaded topology, each power unit 40, as a power converter, such as an H-bridge circuit, needs to be separately provided with a set of locals in addition to a main controller 50. The controller 51, the driving circuit 52, the auxiliary power source 53 and the optical fiber 54 are connected in a relationship as shown in FIG. 4. The main controller 50 outputs a main control signal to the local main controller 51, and the local main controller 51 generates a main control signal according to the main control signal. The local control signal of the corresponding power unit is sent to the driving circuit 52. The driving circuit 52 outputs a driving signal according to the local control signal to drive the corresponding power unit to operate. For example, a 25kV single-phase SVG can usually be implemented in the following two schemes. The first solution: the power switching devices in the H-bridge circuit use the commonly used 1700V Insulated Gate Bipolar Transistor (IGBT), then the DC bus voltage of the single power unit 40 is 1000V, considering redundancy, a total of A 55-level power unit cascade is required, so a total of 55 sets of local control boards 51, 55 sets of fibers 54 and 55 auxiliary power sources 53 are required. Such a large number of local controllers 51, optical fibers 54, and auxiliary power sources 53 will result in extremely complicated structural design of the SVG, and the cost is also relatively high, while reducing its reliability.

The second scheme: the power switching device in the H-bridge circuit uses a high-voltage IGBT, such as a 3300V IGBT or even a 6500V IGBT, to increase the voltage level of a single power unit 40. In order to reduce the number of cascades of power units 40 and reduce the number of local controllers 51, fibers 54, and auxiliary power sources 53, a second scheme can generally be employed. In the second scheme, if the 3300V IGBT is selected, the voltage level of each power unit 40 is doubled compared to the 1700V IGBT scheme, and the number of cascades can be reduced from 55 to 28, local controller 51, fiber 54 and auxiliary power supply. The number and cost of 53 can also be reduced by half. However, due to the current level of semiconductor technology development, the cost of 3300V IGBT is still high. Under the same current specification, the cost is far more than twice the cost of 1700V IGBT. Therefore, the cost of the second option will far exceed the first option. If a 6500V IGBT is chosen, the cost pressure is even higher.

Therefore, the current cascading scheme using low voltage IGBT power units or the cascading scheme using high voltage IGBT power units has its significant disadvantages.

Figure 5 is a schematic illustration of an HVDC-Light system in the prior art. As shown in FIG. 5, the HVDC-Light includes a three-phase circuit, and each phase circuit includes an upper half arm and a lower half arm, and the upper half arm and the lower half arm of each phase circuit include a plurality of stages. Connected power unit 40 and inductor L, each power unit 40 also includes a first end and a second end as shown in FIG. 1, a first end of one of the adjacent two power units 40 and a second of the other The terminals are connected, the inductance L of each upper arm is connected to the inductance L of the corresponding lower arm, and the connection points between the two inductors L are respectively connected to the power grid, and the connection relationship is as shown in FIG. 5. Each of the HVDC-Light power units 40 employs a half bridge converter. Each power unit 40 of the HVDC-Light further includes a DC bus capacitor. Each power unit 40 of the HVDC-Light also needs to be connected to a driving circuit 52. The power unit 40 operates according to a driving signal output by the driving circuit 52. In addition to the main controller 50, each power unit 40 also needs to be provided with a local controller 51, an optical fiber 54 and an auxiliary power supply 53, the connection relationship of which is shown in FIG.

Since the DC voltage of HVDC-Light is as high as hundreds of kilovolts, and the number of power units 40 to be cascaded is extremely large, the above-mentioned problems are more remarkable, that is, the overall structure of HVDC-Light in the prior art is complicated, costly and reliable. Low sex.

In addition, the power supply mode of the local controller and auxiliary power supply needs further consideration and improvement.

In addition, the driving method of the power semiconductor switch needs further consideration and improvement.

In addition, the clamping of the DC bus voltage on the DC bus capacitors needs further consideration and improvement.

Summary of the invention

It is an object of the present invention to provide a modular power supply system that simplifies the structure of a power electronic system, reduces cost, and improves reliability.

According to an aspect of the present invention, a modular power supply system is provided, comprising: a main controller configured to output a main control signal; N local controllers, wherein each of the local controllers is configured to Receiving the main control signal to output at least one local control signal; and N power units in one-to-one correspondence with the N local controllers, wherein each of the power units includes a first end and a second end, each The second end of one of the power units is coupled to the first end of an adjacent one of the power units, each of the power units being configured to include M power converters, wherein each of the powers The converter includes a third end and a fourth end, the fourth end of each of the power converters being coupled to the third end of an adjacent one of the power converters, and the first one of the power conversions The third end of the power unit is the first end of the power unit, and the fourth end of the Mth power converter is the second end of the power unit, each of the power The converter is configured to And operating according to the local control signal outputted by the corresponding local controller, wherein N and M are both natural numbers greater than 1, wherein the power semiconductor of the same position in at least two of the M power converters is controlled The local control signals that are simultaneously turned on and off at the same time are the same.

In some exemplary embodiments of the present invention, the modular power supply system is configured to further include: N auxiliary power sources in one-to-one correspondence with the N local controllers, wherein each of the auxiliary power sources is configured To provide power to the corresponding local controller.

In some exemplary embodiments of the invention, wherein the N auxiliary power sources are configured to draw power from an external power source or to draw power from a corresponding one of the power units.

In some exemplary embodiments of the invention, wherein the power converter is any one of an AC/DC converter, a DC/AC converter, and a DC/DC converter.

In some exemplary embodiments of the invention, the topologies of the M power converters are all identical, or partially identical.

In some exemplary embodiments of the present invention, the topology of the M power converters in each of the power units is all a full bridge converter, a half bridge converter, and a neutral point controllable three level One of a converter, a diode clamped three-level converter, a flying capacitor three-level converter, a full-bridge resonant converter, and a half-bridge resonant converter.

In some exemplary embodiments of the present invention, the topology of the M power converters in each of the power units is a full bridge converter, a half bridge converter, and a neutral point controllable three-level conversion Two or more combinations of a diode, a diode clamped three-level converter, a flying capacitor three-level converter, a full-bridge resonant converter, and a half-bridge resonant converter.

In some exemplary embodiments of the present invention, each of the power units further includes: M driving circuits in one-to-one correspondence with the M power converters, wherein each of the driving circuits is configured to be connected to Corresponding power semiconductor switch of the power converter receives the local control signal output by the corresponding local controller to output at least one driving signal to drive the power in the corresponding M power converters The semiconductor switch is turned on and off.

In some exemplary embodiments of the present invention, each of the power units further includes: a plurality of driving circuits, wherein the number of the plurality of driving circuits is equal to the number of power semiconductor switches in the power unit, each of The driving circuit is configured to be connected to the power semiconductor switch of the corresponding power converter, receive a corresponding local control signal output by the local controller, to output a driving signal to drive the corresponding power semiconductor switch Turn on and off.

In some exemplary embodiments of the invention, each of the drive circuits is identical to each other or different from each other.

In some exemplary embodiments of the present invention, each of the driving circuits includes a first magnetic isolation device that transmits a driving logic pulse and a power pulse included in the local control signal; or each One of the drive circuits includes a second magnetic isolation device that transmits drive logic pulses included in the local control signal.

In some exemplary embodiments of the present invention, a portion of the driving circuit includes a first magnetic isolation device that transmits a driving logic pulse and a power pulse included in the local control signal; The drive circuit includes a second magnetic isolation device that transmits drive logic pulses included in the local control signal.

In some exemplary embodiments of the present invention, wherein at least one of the M power converters is a main power converter, at least one is a slave power converter, and at least one of the M driving circuits is a main driving circuit. At least one is a slave drive circuit configured to drive a corresponding power semiconductor switch in the main power converter to be turned on and off, the slave drive circuit configured to drive the corresponding slave power The power semiconductor switches in the converter are turned on and off.

In some exemplary embodiments of the present invention, wherein the main power converter and the slave power converter are controlled when a topology of the master power converter is the same as a topology of the slave power converter The local control signals of the same position of the power semiconductor switch being simultaneously turned on and simultaneously turned off are the same.

In some exemplary embodiments of the present invention, wherein the number of the at least one main power converter is 1, and the number of the at least one slave power converter is M-1, controlling the same in the slave power converter The local control signals of the position of the power semiconductor switch being simultaneously turned on and simultaneously turned off are the same.

In some exemplary embodiments of the present invention, wherein when the number of the at least one main power converter is greater than or equal to 2 and the number of the at least one slave power converter is greater than or equal to 2, the slave power converter is controlled The local control signals of the same position of the power semiconductor switch being simultaneously turned on and simultaneously turned off are the same.

In some exemplary embodiments of the present invention, wherein the power semiconductor switch of the same position in the main power converter is controlled when the topology of the main power converter is different from the topology of the slave power converter The local control signals that are turned on and off at the same time are the same.

In some exemplary embodiments of the present invention, wherein when the topology of the main power converter is the same as the topology of the slave power converter, the same position of the power semiconductor switch in the main power converter is controlled simultaneously The local control signals that are turned on and off at the same time are the same.

In some exemplary embodiments of the present invention, wherein the main driving circuit and the slave driving circuit each include a magnetic isolation device that transmits driving logic pulses and power pulses included in the local control signal; Or the magnetic isolation device transmits a drive logic pulse included in the local control signal.

In some exemplary embodiments of the present invention, wherein the main drive circuit includes a main magnetic isolation device, the slave drive circuit includes a slave magnetic isolation device, wherein the main magnetic isolation device transmits a signal included in the local control signal Driving a logic pulse, the driving logic pulse and power pulse included in the local control signal being transmitted from a magnetic isolation device; or the main magnetic isolation device transmitting a driving logic pulse and a power pulse included in the local control signal, The drive logic pulses included in the local control signal are transmitted from the magnetic isolation device.

In some exemplary embodiments of the present invention, each of the main driving circuit and each of the slave driving circuits includes a magnetic isolation device that transmits a driving logic pulse included in the local control signal And a power pulse, or the magnetic isolation device transmits a drive logic pulse included in the local control signal.

In some exemplary embodiments of the present invention, wherein the main drive circuit includes a main magnetic isolation device, the slave drive circuit includes a slave magnetic isolation device, wherein the main magnetic isolation device transmits a signal included in the local control signal Driving a logic pulse, the driving logic pulse and the power pulse contained in the local control signal are transmitted from the magnetic isolation device, or the main magnetic isolation device transmits a driving logic pulse and a power pulse included in the local control signal, The drive logic pulses included in the local control signal are transmitted from the magnetic isolation device.

In some exemplary embodiments of the present invention, each of the power units further includes: a plurality of first DC bus voltage clamping circuits, one-to-one corresponding to the slave power converters, wherein each of the A DC bus voltage clamping circuit is configured to be coupled in parallel with the corresponding DC bus capacitance of the slave power converter such that the DC bus voltage of the corresponding slave power converter does not exceed a first predetermined value.

In some exemplary embodiments of the present invention, each of the first DC bus voltage clamping circuits includes: a switch, a resistor, and a switch control circuit, wherein the switch forms a series branch with the resistor, a series branch circuit is connected in parallel with the DC bus capacitor, the switch control circuit is connected to the control end of the switch, and when the DC bus voltage exceeds the first preset value, the switch control circuit outputs a switch control signal to The switch is turned on such that the DC bus capacitor is discharged through the series branch.

In some exemplary embodiments of the present invention, each of the power units further includes:

a plurality of first DC bus voltage clamping circuits in one-to-one correspondence with the slave power converters, wherein each of the first DC bus voltage clamping circuits is configured to be coupled to a DC bus of a corresponding slave power converter The capacitors are connected in parallel such that the DC bus voltage of the corresponding slave power converter does not exceed a first preset value;

a plurality of second DC bus voltage clamping circuits in one-to-one correspondence with the main power converter, wherein each of the second DC bus voltage clamping circuits is configured to be in parallel with a DC bus capacitance of a corresponding main power converter So that the corresponding DC bus voltage of the main power converter does not exceed a second preset value.

In some exemplary embodiments of the present invention, each of the first DC bus voltage clamping circuits includes: a switch, a resistor, and a switch control circuit, wherein the switch forms a series branch with the resistor, a series branch circuit is connected in parallel with the DC bus capacitor, the switch control circuit is connected to the control end of the switch, and when the DC bus voltage exceeds the first preset value, the switch control circuit outputs a switch control signal to Turning on the switch such that the DC bus capacitor is discharged through the series branch;

Each of the second DC bus voltage clamping circuits includes:

a switch, a resistor, and a switch control circuit, wherein the switch forms a series branch with the resistor, the series branch is coupled in parallel with the DC bus capacitor, and the switch control circuit is coupled to the control end of the switch when When the DC bus voltage exceeds the second predetermined value, the switch control circuit outputs a switch control signal to turn on the switch such that the DC bus capacitor is discharged through the series branch.

The invention can reduce the number of local controllers, optical fibers and auxiliary power sources by simplifying the structure by forming a plurality of power converters into one power unit and using a local controller, an optical fiber, and an auxiliary power source to control multiple power converters. Design, reduce costs and improve reliability.

The invention simplifies the control circuit by sharing a drive signal at the same position of the power semiconductor switches at the same position of the power converters in the power unit.

The invention is applicable to the topology of all AC/DC, DC/AC, DC/DC power converter connections and is widely used.

DRAWINGS

The above and other objects, features and advantages of the present invention will become more apparent from the embodiments of the invention.

1 is a schematic structural view of a three-phase SVG system in the prior art;

2 is a schematic diagram of a more specific three-phase SVG system in the prior art;

3 is a schematic diagram of an H-bridge circuit (topology) in the prior art;

4 is a schematic diagram of a single phase SVG in the prior art;

Figure 5 is a schematic diagram of an HVDC-Light system in the prior art;

Figure 6 is a block diagram of a modular power supply system in accordance with one embodiment of the present invention;

Figure 7 is a block diagram of a modular power supply system in accordance with another embodiment of the present invention;

Figure 8 is a block diagram of a modular power supply system in accordance with another embodiment of the present invention;

Figure 9 is a block diagram of a modular power supply system in accordance with another embodiment of the present invention;

Figure 10 is a block diagram of a modular power supply system in accordance with another embodiment of the present invention;

Figure 11 is a block diagram of a modular power supply system in accordance with another embodiment of the present invention;

Figure 12 is a block diagram of a modular power supply system in accordance with another embodiment of the present invention;

Figure 13 is a block diagram of a modular power supply system in accordance with another embodiment of the present invention;

Figure 14 is a block diagram of a modular power supply system in accordance with another embodiment of the present invention;

Figure 15 is a block diagram of a modular power supply system in accordance with another embodiment of the present invention;

Figure 16 is a schematic view showing the manner of connection between the local controller and the driving circuit of the present invention;

Figure 17 is a block diagram of a modular power supply system in accordance with another embodiment of the present invention;

Figure 18 is a schematic view showing the driving mode of the driving circuit of the present invention;

Figure 19 is a schematic view showing another driving mode of the driving circuit of the present invention;

Figure 20 is a circuit diagram of a driving circuit of one embodiment of the present invention;

Figure 21 is a timing chart of a driving circuit of one embodiment of the present invention;

Figure 22 is a block diagram of a modular power supply system in accordance with another embodiment of the present invention;

23 is a block diagram of a modular power supply system in accordance with another embodiment of the present invention;

Figure 24 is a block diagram of a modular power supply system in accordance with another embodiment of the present invention;

Figure 25 is a block diagram of a modular power supply system in accordance with another embodiment of the present invention;

Figure 26 is a block diagram of a modular power supply system in accordance with another embodiment of the present invention;

Figure 27 is a circuit diagram of a clamp circuit according to an embodiment of the present invention;

28 is a block diagram of a modular power supply system in accordance with another embodiment of the present invention.

Specific embodiment

Example embodiments will now be described more fully with reference to the accompanying drawings. However, the exemplary embodiments can be embodied in a variety of forms and should not be construed as being limited to the examples set forth herein; rather, these embodiments are provided to make the present invention more comprehensive and complete, and fully convey the concept of the example embodiments. To those skilled in the art. The drawings are only schematic representations of the invention and are not necessarily to scale. The same reference numerals in the drawings denote the same or similar parts, and the repeated description thereof will be omitted.

Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are set forth However, one skilled in the art will appreciate that the technical solution of the present invention may be practiced, and one or more of the specific details may be omitted, or other methods, components, devices, steps, etc. may be employed. In other instances, well-known structures, methods, apparatus, implementations, or operations are not shown or described in detail to avoid obscuring aspects of the invention.

Figure 6 is a block diagram of a modular power system in accordance with one embodiment of the present invention. As shown in FIG. 6, the modular power supply system of the present invention is configured to include: a main controller 90, N local controllers 91, and N power units 70, where N is a natural number greater than one.

The main controller 90 is configured to output a main control signal. The primary control signal is, for example, one or more parameters that are set to control the overall operational state of the modular power system.

Each local controller 91 is configured to receive the aforementioned primary control signal to output at least one local control signal. The local control signal is, for example, one or more parameters that are set to control the overall operational state of the corresponding power unit 70, or the local control signal is used to control the operational state of a portion of the power converters in the corresponding power unit 70.

The modular power system of the present invention can be configured to further include N auxiliary power sources 93, one for each of the N local controllers 91, wherein each of the auxiliary power sources 93 is configured to correspond to a corresponding local controller 91 provides power.

N power unit 70 and local controllers 91 of the N-one correspondence, each of the power unit 70 includes a first end and a second end X ₁ X _2, each of the second end of the power unit 70 is connected to the adjacent X ₂ The first end X _{1 of} one power unit 70, that is, the second end X ₂ of one of the adjacent two power units 70 is coupled to the first end X _{1 of the} other.

Each power unit 70 is configured to include M power converters 701, each of which includes a third end X ₃ and a fourth end X ₄ , each of which is coupled to a fourth end X ₄ o a third terminal 701 of power converter X _3. That is, the fourth end X ₄ of one of the adjacent two power converters 701 is connected to the third end X _{3 of the} other. M is a natural number greater than one. Thus, the third end X _{3 of} the first power converter 701 is the first end X _{1 of} the power unit 70, and the fourth end X _{4 of} the Mth power converter 701 is the second end of the power unit 70. X _2. Each power converter 701 is configured to operate according to a local control signal output by a corresponding local controller 91, wherein a power semiconductor switch of the same position in at least two of the M power converters is controlled to be simultaneously turned on The local control signals that are disconnected at the same time are the same.

As an embodiment, the local control signals corresponding to the partial power converters are shared, and the local control signals corresponding to the other power converters are independent, that is, in the power converter sharing the local control signals, the same The local control signal controls the power semiconductor switches in the same position to be turned on and off at the same time.

As another embodiment, the local control signals corresponding to the M power converters are all shared, and the same local control signal controls the power semiconductor switches of the same position in the M power converters to be simultaneously turned on and off at the same time.

As an embodiment of the present invention, the aforementioned main control signal can be transmitted between the main controller 90 and each of the local controllers 91 via an optical isolation device, such as an optical fiber 94. In other embodiments, the main controller 90 and each local controller 91 can be connected by a magnetic isolation device, such as an isolation transformer, and the connection between the main controller 90 and each local controller 91 is not only Limited to the above connection method.

The modular power supply system of the present invention can be applied to fields such as SVG, MVD, HVDC-Light, and wind power generation systems.

As shown in FIG. 6, the present invention proposes to synthesize M power converters 701 into one power unit 70. One power unit 70 is provided with a local controller 91, an optical fiber 94 and an auxiliary power source 93, that is, a set of local controllers 91. The fiber 94 and the auxiliary power source 93 control the M power converters 701. In the conventional solution, each power unit 40, that is, the power converter, needs to be configured with a local controller 51, an optical fiber 54, and an auxiliary power supply 53. Compared with the conventional solution, the number of local controller 91, optical fiber 94 and auxiliary power supply 93 required for the modular power supply system proposed by the present invention will be reduced to 1/M of the conventional solution. The invention greatly simplifies the structural design of the modular power supply system, and the cost is also significantly reduced, and the reliability is greatly improved.

The present invention does not limit the topology used in each power converter 701. The M power converters 701 in the modular power system of the present invention may be in an AC/DC converter, a DC/AC converter, and a DC/DC converter. Any of these, so power converter 701 in Figure 6 represents any of the applicable AC/DC, DC/AC, and DC/DC topologies. The present invention does not limit the topology used in the M power converters 701. The topology of the M power converters may be all the same or partially identical. For example, the topology of the M power converters 701 in each power unit 70 of the modular power supply system of the present invention may all be a full bridge converter, a half bridge converter, and a neutral point controllable three level converter. One of a diode clamped three-level converter, a flying capacitor three-level converter, a full-bridge resonant converter, and a half-bridge resonant converter. Or for example, the topology of the M power converters 701 in each power unit 70 in the modular power system of the present invention may be a full bridge converter, a half bridge converter, a neutral point controllable three level converter A combination of two or more of a diode clamped three-level converter, a flying capacitor three-level converter, a full-bridge resonant converter, and a half-bridge resonant converter.

As shown in FIG. 6, each power unit 70 in the modular power supply system of the present embodiment may include: M drive circuits 702, one-to-one corresponding to M power converters 701, wherein each of the drive circuits 702 is configured For connecting to the power semiconductor switch in the corresponding power converter 701, receiving and according to at least one local control signal output by the corresponding local controller 91, outputting at least one driving signal to drive the corresponding M power converters 701 Turning on and off the power semiconductor switch.

In other embodiments, each power unit in the modular power system can include: a plurality of drive circuits, the number of the plurality of drive circuits being equal to the number of power semiconductor switches in the power unit, each drive circuit being configured to be coupled to A corresponding power semiconductor switch receives and outputs a driving signal to drive the corresponding power semiconductor switch on and off according to the corresponding local control signal.

As shown in FIG. 6, each power unit 70 in the modular power supply system of the present embodiment may include: M drive circuits 702, one-to-one corresponding to M power converters 701, wherein each of the drive circuits 702 is configured In order to connect to the power semiconductor switch in the corresponding power converter 701, the local control signal outputted by the corresponding local controller 91 is received to output at least one driving signal to drive the power semiconductor switch in the corresponding M power converters 701. Turn on and off.

As shown in FIG. 6, the local control signals corresponding to the first power converter 701 and the second power converter 701 in the power unit 70 are common, that is, the same position in the two power converters 701 is controlled. The local control signals that are simultaneously turned on and off simultaneously by the power semiconductor switch are the same; and the local control signals corresponding to the third power converter 701 are independent, that is, they are identical to the first power converter 701. The local control signal of the second power converter 701 is not the same. In other words, the third power converter 701 is independently controlled and the first power converter 701 and the second power converter 701 are jointly controlled.

In other embodiments, the local control signals corresponding to the first power converter 701, the second power converter 701, and the third power converter 701 are common, that is, the three power converters 701 are Jointly controlled. It should be noted that there are M power converters in the power unit 70, and here are three, but not limited to three.

In each of the power units 70 of the modular power supply system of the present embodiment, the power converter 701 employing the same topology may employ a "common drive." By "shared drive" is meant that the power semiconductor switches at the same location of each converter 701 of the same topology can be controlled using the same local control signal. By "same position" is meant the position of the logically corresponding power semiconductor switch in each power converter 701 of the same topology in the circuit diagram. For example, the power semiconductor switches Q ₁₁ , Q ₂₁ ... Q _M1 in the respective power converters 701 of the same topology in FIGS. 7 to 15 have the same position, and Q ₁₂ , Q ₂₂ ... Q _M2 have the same The positions Q ₁₈ , Q ₂₈ ... Q _M8 have the same position, so the M power converters 701 in each of the power units 70 in the following FIGS. 7 to 15 can adopt the "common drive".

By adopting the "common drive" driving method of the invention, the number of local control signals can be greatly reduced, and the circuit design of the local control can be simplified. 7 to FIG. 15 further describe the driving mode of the "common drive" of the present invention, that is, the local control signals corresponding to the power converter 701 are the same, that is, the M power converters 701 are jointly controlled, specifically, The local control signals corresponding to the power semiconductor switches at the same position in the M power converters 701 are the same.

The related contents of the main controller 90, the local controller 91, the optical fiber 94, and the auxiliary power source 93 have been described in FIG. 6, and are not described herein again. Figures 7-15 depict only the local control signals corresponding to the M power converters in a power unit 70 and the corresponding drive circuits.

Figure 7 is a block diagram of a modular power system in accordance with another embodiment of the present invention. As shown in FIG. 7, the topology of each power converter 701 of the same power unit 70 is a full bridge converter, such as an H bridge circuit. Taking the Mth H-bridge circuit as an example, the H-bridge circuit includes two bridge arms. For example, one bridge arm of the M-th H-bridge circuit includes an upper power semiconductor switch Q _M1 and a lower power semiconductor switch Q _M2 , and the other bridge arm The upper power semiconductor switch Q _M3 and the lower power semiconductor switch Q _{M4 are included} . The connection point of the upper power semiconductor switch Q _M1 and the lower power semiconductor switch Q _M2 is the third output terminal X ₃ of the Mth power converter 401. The connection point of the upper power semiconductor switch Q _M3 and the lower power semiconductor switch Q _M4 is the fourth output terminal X ₄ of the Mth power converter 401.

In the present embodiment, the third output terminal X _{3 of} one of the adjacent two power converters 701 is sequentially connected to the fourth output terminal X _{4 of the} other one. Specifically, the third output terminal X ₃ of the first H-bridge circuit is the first terminal X ₁ of the power unit 70, and the fourth output terminal X ₄ of the first H-bridge circuit and the second H-bridge circuit The three output terminals X _{3 are} connected in turn, and the fourth output terminal X ₄ of the M-1th H-bridge circuit is connected to the third output terminal X ₃ of the M-th H-bridge circuit, and the M-th H-bridge circuit is connected. The four output terminal X ₄ is the second terminal X ₂ of the power unit 70.

In the present embodiment, the local controller 91 outputs four local control signals. Each H-bridge circuit corresponds to a drive circuit 702. Each of the driving circuits 702 is coupled to the local controller 91, and is connected to the control terminals of the corresponding upper power semiconductor switch and the lower power semiconductor switch for receiving the above four local control signals output by the local controller 91, and is localized. The control signals are processed to produce respective four drive signals. For example, the generated four drive signals Y _M1 , Y _M2 , Y _{M3 ,} and Y _{M4 are} output to the control terminals of the upper power semiconductor switches Q _M1 and Q _M3 and the lower power semiconductor switches Q _M2 and Q _M4 in the Mth H-bridge circuit, It is used to drive the on and off of the upper power semiconductor switches Q _M1 and Q _M3 and the lower power semiconductor switches Q _M2 and Q _M4 .

In this embodiment, the local control signals corresponding to the power semiconductor switches of the same position of each H-bridge circuit are the same, that is, the local control signals are the same, for example, the upper power semiconductor switch Q _{11 of the} first H-bridge circuit, The upper power semiconductor switch Q _{21 of the} second H-bridge circuit, and so on, until the local control signal corresponding to the upper power semiconductor switch Q _M1 of the M-th H-bridge circuit is the same, that is, the same local control signal, that is, the output of the driving circuit 702 The corresponding drive signals Y ₁₁ , Y ₂₁ ... Y _{M1 are} identical, such that the upper power semiconductor switches Q ₁₁ , Q ₂₁ ... Q _{M1 are} simultaneously turned on and simultaneously turned off. Since the topology of each power converter 701 in the power unit 70 in this embodiment uses an H-bridge circuit, one power unit 70 requires only a local controller 91, an optical fiber 94, and an auxiliary power source 93. In this embodiment, the power semiconductor switches at the same position of the respective H-bridge circuits use the same local control signal, so that only one local control signal is required in one power unit 70.

Figure 8 is a block diagram of a modular power system in accordance with another embodiment of the present invention. As shown in FIG. 8, the topology of each of the power converters 701 in the same power unit 70 is a half bridge converter. Taking the Mth half-bridge converter as an example, the half-bridge converter includes one bridge arm 111. For example, the bridge arm 111 of the M-th half-bridge circuit includes an upper power semiconductor switch Q _M1 and a lower power semiconductor switch Q _M2 . A connection point of one end of the upper power semiconductor switch Q _M1 and the lower power semiconductor switch Q _M2 is a third output terminal X ₃ of the Mth power converter 701. The other end of the lower power semiconductor switch Q _M2 is the fourth output terminal X ₄ of the Mth power converter 701.

In the present embodiment, the third output terminal X _{3 of} one of the adjacent two power converters 701 is sequentially connected to the fourth output terminal X _{4 of the} other one. Specifically, the third output terminal X ₃ of the first half bridge converter is the first end X ₁ of the power unit 70, and the fourth output terminal X ₄ and the second half bridge of the first half bridge converter are transformed. The third output terminal X _{3 of the device is} connected and connected in turn, and the fourth output terminal X _{4 of} the M-1 half bridge converter is connected with the third output terminal X _{3 of} the Mth half bridge converter, the Mth the fourth output X ₄ is a half-bridge converter power unit 70 of the second end of X _2.

In the present embodiment, the local controller 91 outputs two local control signals. Each half bridge converter corresponds to a drive circuit 702. Each of the driving circuits 702 is coupled to the local controller 91 and is connected to the control terminals of the corresponding upper power semiconductor switch and the lower power semiconductor switch for receiving the two local control signals output by the local controller 91 and local The control signals are processed to produce respective two drive signals. For example, the generated two drive signals Y _M1 and Y _{M2 are} output to the control terminals of the upper power semiconductor switch Q _M1 and the lower power semiconductor switch Q _M2 in the Mth half-bridge converter for driving the upper power semiconductor switch Q _M1 and the lower The power semiconductor switch Q _M2 is turned on and off.

In this embodiment, the local control signals corresponding to the power semiconductor switches of the same position of each half-bridge converter are the same, that is, the local control signals are the same, for example, the upper power semiconductor switch Q of the first half-bridge converter. _11. The upper power semiconductor switch Q _{21 of the} second H-bridge circuit, and so on, until the local control signal corresponding to the upper power semiconductor switch Q _M1 of the M-th half-bridge converter is the same, that is, the output of the drive circuit 702 is corresponding. The drive signals Y ₁₁ , Y ₂₁ ... Y _{M1 are} identical, such that the upper power semiconductor switches Q ₁₁ , Q ₂₁ ... Q _{M1 are} simultaneously turned on and simultaneously turned off. Since the topology of each power converter 701 in the power unit 70 in this embodiment uses a half bridge converter, one power unit 70 requires only a local controller 91, an optical fiber 94, and an auxiliary power source 93. In this embodiment, the power semiconductor switches at the same position of each half-bridge converter use the same local control signal, so that only one local control signal is required in one power unit 70.

9 is a block diagram of a modular power supply system in accordance with another embodiment of the present invention. As shown in FIG. 9, the topology of each of the power converters 701 in the same power unit 70 is a neutral point controllable three-level converter. Taking the first neutral point controllable three-level converter as an example, the neutral point controllable three-level converter includes a first bridge arm 111a and a second bridge arm 111b. The first bridge arm 111a and the second bridge arm 111b each include an upper power semiconductor switch (such as Q ₁₁ , Q ₁₅ ) and a lower power semiconductor switch (such as Q ₁₂ , Q ₁₆ ). The neutral point controllable three-level converter further includes a first DC bus capacitor C ₁ , a second DC bus capacitor C ₂ , a first switch group (such as Q ₁₃ , Q ₁₄ ) and a second switch group (such as Q ₁₇₎ , Q ₁₈ ). The first DC bus capacitor C ₁ and the second DC bus capacitor C _{2 are} connected in series and connected in parallel with the first bridge arm 111a and the second bridge arm 111b. The connection point of the upper power semiconductor switch Q ₁₁ and the lower power semiconductor switch Q ₁₂ of the first bridge arm 111a is the third output terminal X _{3 of the} first power converter 701. The connection point of the upper power semiconductor switch Q ₁₅ and the lower power semiconductor switch Q ₁₆ of the second bridge arm 111b is the fourth output terminal X _{4 of the} first power converter 701. The first switch group (such as Q ₁₃ , Q ₁₄ ) is connected to the connection point of the upper power semiconductor switch Q ₁₁ and the lower power semiconductor switch Q ₁₂ of the first bridge arm 111a with the first DC bus capacitor C ₁ and the second DC bus Capacitor C ₂ is connected between the points. The second switch group (such as Q ₁₇ , Q ₁₈ ) is connected to the connection point of the upper power semiconductor switch Q ₁₅ and the lower power semiconductor switch Q ₁₆ of the second bridge arm 111b with the first DC bus capacitor C ₁ and the second DC bus Capacitor C ₂ is connected between the points. In this embodiment, the first switch group is formed by connecting two power semiconductor switches in series. For example, the two power semiconductor switches may be bidirectional controllable switches.

In the present embodiment, the third output terminal X _{3 of} one of the adjacent two power converters 701 is sequentially connected to the fourth output terminal X _{4 of the} other one. Specifically, the third output terminal X ₃ of the first neutral point controllable three-level converter is the first end X ₁ of the power unit 70, and the first neutral point controllable three-level converter The four output terminals X _{4 are} connected to the third output terminal X _{3 of the} second neutral point controllable three-level converter, and are sequentially connected, and the fourth M-1 neutral point controllable three-level converter The output terminal X _{4 is} connected to the third output terminal X ₃ of the Mth neutral point controllable three-level converter, and the fourth output terminal X ₄ of the Mth neutral point controllable three-level converter is a power unit The second end of 70 is X ₂ .

In this embodiment, the local controller 91 outputs eight local control signals, each of which is used to control a corresponding upper power semiconductor switch (such as Q ₁₁ , Q ₁₅ ) and a lower power semiconductor switch (such as Q ₁₂ , Q). ₁₆ ), one of the first switch group (such as Q ₁₃ , Q ₁₄ ) and the second switch group (such as Q ₁₇ , Q ₁₈ ). The local control signals corresponding to the power semiconductor switches of the same position of each neutral point controllable three-level converter are the same, that is, the local control signals are the same, and the neutral point controllable three-level converter in the power unit For example, the first power semiconductor switch of the first neutral point controllable three-level converter, the first power semiconductor switch Q ₁₁ of the first neutral point controllable three-level converter, and the first power semiconductor switch of the second neutral point controllable three-level converter Q ₂₁ , and so on until the first power semiconductor switch Q _M1 of the Mth neutral point controllable three-level converter corresponds to the same local control signal, that is, the local control signal is the same, that is, the corresponding drive of the drive circuit output The signals Y ₁₁ , Y ₂₁ ... Y _{M1 are} identical such that the first power semiconductor switches Q ₁₁ , Q ₂₁ up to Q _{M1 are} simultaneously turned on and off at the same time. Since the topology of each power converter 701 in the power unit 70 in this embodiment uses a neutral point controllable three-level converter, one power unit 70 requires only a local controller 91, an optical fiber 94, and an auxiliary power source 93. The power semiconductor switches at the same position of each neutral point controllable three-level converter in this embodiment use the same local control signal, so that one power unit 70 requires only a total of eight local control signals.

Figure 10 is a block diagram of a modular power system in accordance with another embodiment of the present invention. As shown in FIG. 10, the topology of each of the power cells 70 in the same power unit 70 is a diode clamped three-level converter. Taking the first diode clamped three-level converter as an example, the diode clamped three-level converter includes a first bridge arm 111a and a second bridge arm 111b. The first bridge arm 111a and the second bridge arm 111b each include a first power semiconductor switch (such as Q ₁₁ , Q ₁₅ ), a second power semiconductor switch (such as Q ₁₂ , Q ₁₆ ), and a third power semiconductor switch (such as Q ₁₃ , Q ₁₇ ) and a fourth power semiconductor switch (such as Q ₁₄ , Q ₁₈ ). The diode clamped three-level converter further includes a first DC bus capacitor C ₁ , a second DC bus capacitor C ₂ , a first diode D ₁ , a second diode D ₂ , and a third diode D ₃ And a fourth diode D ₄ . The first DC bus capacitor C ₁ and the second DC bus capacitor C _{2 are} connected in series and connected in parallel with the first bridge arm 111a and the second bridge arm 111b. The first power semiconductor switch Q ₁₁ , the second power semiconductor switch Q ₁₂ , the third power semiconductor switch Q ₁₃ and the fourth power semiconductor switch Q _{14 of the} first bridge arm 111 a are connected in series. The connection point of the second power semiconductor switch Q ₁₂ and the third power semiconductor switch Q ₁₃ is the third output terminal X _{3 of} the power converter 401. The first power semiconductor switch Q ₁₅ , the second power semiconductor switch Q ₁₆ , the third power semiconductor switch Q ₁₇ and the fourth power semiconductor switch Q _{18 of the} second bridge arm 111b are connected in series. The junction point of the second power semiconductor switch Q ₁₆ and the third power semiconductor switch Q ₁₇ is the fourth output terminal X _{4 of} the power converter 401. The first diode D ₁ and the second diode D _{2 are} connected in series and connected to the connection point of the first power semiconductor switch Q ₁₁ and the second power semiconductor switch Q ₁₂ of the first bridge arm 111a and the third power semiconductor switch Q and the fourth power semiconductor switch ₁₃ between the connection point Q _14. The third diode D ₃ and the fourth diode D _{4 are} connected in series and connected to the connection point of the first power semiconductor switch Q ₁₆ and the second power semiconductor switch Q ₁₇ of the second bridge arm 111b and the third power semiconductor switch Q and the fourth power semiconductor switch ₁₇ between the connection point Q _18. A connection point of the first diode D ₁ and the second diode D ₂ is connected to a connection point of the first DC bus capacitor C ₁ and the second DC bus capacitor C ₂ . The junction of the third diode D ₃ and the fourth diode D ₄ is also connected to the junction of the first DC bus capacitor C ₁ and the second DC bus capacitor C ₂ . In this embodiment, the first diode D ₁ and the second diode D ₂ function as clamping diodes, a first power semiconductor switch, a second power semiconductor switch, a third power semiconductor switch, and a fourth power semiconductor. The switch is an IGBT or an IGCT.

In the present embodiment, the third output terminal X _{3 of} one of the adjacent two power converters 701 is sequentially connected to the fourth output terminal X _{4 of the} other one. Specifically, the third output terminal X ₃ of the first diode clamped three-level converter is the first terminal X ₁ of the power unit 70, and the fourth output terminal X of the first diode clamped three-level converter _{4 is} connected to the third output terminal X _{3 of the} second diode clamped three-level converter, and sequentially connected, the fourth output terminal X ₄ and the Mth of the M-1th diode clamped three-level converter The third output terminal X ₃ of the diode clamped three-level converter is connected, and the fourth output terminal X ₄ of the Mth diode clamped three-level converter is the second terminal X ₂ of the power unit 70.

In this embodiment, the local controller 91 outputs eight local control signals, each of which is used to control a corresponding first power semiconductor switch (such as Q ₁₁ , Q ₁₅ ) and a second power semiconductor switch (such as Q _12). , Q ₁₆ ), one of a third power semiconductor switch (such as Q ₁₃ , Q ₁₇ ) and a fourth power semiconductor switch (such as Q ₁₄ , Q ₁₈ ). The local control signal corresponding to the power semiconductor switch of the same position of each diode clamped three-level converter is the same, for example, the first power semiconductor switch of the diode clamped three-level converter in the power unit is taken as an example, the first a first power semiconductor switch Q _{11 of} a diode clamped three-level converter, a first power semiconductor switch Q _{21 of} a second diode clamped three-level converter, and so on until the Mth diode clamps three levels The local control signals corresponding to the first power semiconductor switch Q _{M1 of} the converter are the same, that is, the local control signals are the same, that is, the driving circuit outputs the corresponding driving signals Y ₁₁ , Y ₂₁ ... Y _{M1 to be the} same, so that the first The power semiconductor switches Q ₁₁ , Q ₂₁ and Q _{M1 are} simultaneously turned on and off at the same time. Since each of the power converters 701 in the power unit 70 in this embodiment employs a diode clamped three-level converter, one power unit 70 requires only a local controller 91, an optical fiber 94, and an auxiliary power source 93. In this embodiment, the power semiconductor switches at the same position of the diode clamped three-level converters use the same local control signal, so that only one local control signal is required for one power unit.

11 is a block diagram of a modular power supply system in accordance with another embodiment of the present invention. As shown in FIG. 11, the topology of each of the power converters 701 in the same power unit 70 is a flying capacitor three-level converter. Taking the first flying capacitor three-level converter as an example, the flying capacitor three-level converter includes a first bridge arm 111a and a second bridge arm 111b. The first bridge arm 111a and the second bridge arm 111b each include a first power semiconductor switch (Q ₁₁ , Q ₁₅ ), a second power semiconductor switch (Q ₁₂ , Q ₁₆ ), and a third power semiconductor switch (Q ₁₃ , Q _{17 )} And a fourth power semiconductor switch (Q ₁₄ , Q ₁₈ ). Flying capacitor three-level converter further comprises a first DC bus capacitor C _1, a first DC bus capacitor C _2, the first capacitor and the second capacitor C ₃ C _4. The first DC bus capacitor C ₁ and the first DC bus capacitor C _{2 are} connected in series and connected in parallel with the first bridge arm 111a and the second bridge arm 111b. The first power semiconductor switch Q ₁₁ , the second power semiconductor switch Q ₁₂ , the third power semiconductor switch Q ₁₃ and the fourth power semiconductor switch Q _{14 of the} first bridge arm 111 a are connected in series. The connection point of the second power semiconductor switch Q ₁₂ and the third power semiconductor switch Q ₁₃ is the third output terminal X _{3 of} the power converter 401. The first power semiconductor switch Q ₁₅ , the second power semiconductor switch Q ₁₆ , the third power semiconductor switch Q ₁₇ and the fourth power semiconductor switch Q _{18 of the} second bridge arm 111b are connected in series. The junction point of the second power semiconductor switch Q ₁₆ and the third power semiconductor switch Q ₁₇ is the fourth output terminal X _{4 of} the power converter 401. The first capacitor C _{3 is} connected to the connection point of the first power semiconductor switch Q ₁₁ and the second power semiconductor switch Q ₁₂ of the first bridge arm 111a and the third power semiconductor switch Q ₁₃ and the fourth power semiconductor of the first bridge arm 111a Q switch ₁₄ between the connection point. The second capacitor C _{4 is} connected to the connection point of the first power semiconductor switch Q ₁₅ and the second power semiconductor switch Q ₁₆ of the second bridge arm 111b and the third power semiconductor switch Q ₁₇ and the fourth power semiconductor of the second bridge arm 111b Between the connection points of switch Q ₁₈ .

In the present embodiment, the third output terminal X _{3 of} one of the adjacent two power converters 701 is sequentially connected to the fourth output terminal X _{4 of the} other one. Specifically, the third output terminal X ₃ of the first flying capacitor three-level converter is the first end X ₁ of the power unit 70, and the fourth output terminal X of the first flying capacitor three-level converter _{4 is} connected to the third output terminal X _{3 of the} second flying capacitor three-level converter, and sequentially connected, the fourth output terminal X ₄ and the Mth of the M-1 flying capacitor three-level converter The third output terminal X ₃ of the flying capacitor three-level converter is connected, and the fourth output terminal X _{4 of} the Mth flying capacitor three-level converter is the second terminal X _{2 of} the power unit 70.

In this embodiment, the local controller 91 outputs eight local control signals, each of which is used to control a corresponding first power semiconductor switch (such as Q ₁₁ , Q ₁₅ ) and a second power semiconductor switch (such as Q _12). , Q ₁₆ ), one of a third power semiconductor switch (such as Q ₁₃ , Q ₁₇ ) and a fourth power semiconductor switch (such as Q ₁₄ , Q ₁₈ ). The local control signal corresponding to the power semiconductor switch of the same position of each flying capacitor three-level converter is the same, for example, the first power semiconductor switch of the flying capacitor three-level converter in the power unit is taken as an example, the first a first power semiconductor switch Q _{11 of} a flying capacitor three-level converter, a first power semiconductor switch Q _{21 of} a second flying capacitor three-level converter, and so on until a third level of the Mth flying capacitor The local control signal corresponding to the first power semiconductor switch Q _{M1 of} the converter is the same, that is, the driving circuit outputs corresponding driving signals Y ₁₁ , Y ₂₁ ... Y _{M1 are the} same, so that the first power semiconductor switches Q ₁₁ , Q ₂₁ Until Q _M1 is turned on and off at the same time. Since each power converter 701 in the power unit 70 in this embodiment employs a flying capacitor three-level converter, one power unit 70 requires only one local controller 91, an optical fiber 94, and an auxiliary power source 93. In this embodiment, the power semiconductor switches at the same position of each of the flying capacitor three-level converters use the same local control signal, so that only one local control signal is required for one power unit.

Figure 12 is a block diagram of a modular power supply system in accordance with another embodiment of the present invention. As shown in FIG. 12, the topology of each of the power converters 701 in the same power unit 70 is a full bridge resonant converter. The full bridge resonant converter 701 includes a full bridge circuit, a resonant circuit, a transformer, and a rectifier bridge, the connection relationship of which is as shown in FIG. Taking the first full-bridge resonant converter 701 as an example, the full-bridge circuit includes four power semiconductor switches and one DC bus capacitor. One end of the power semiconductor switch Q ₁₁ is connected to one end of the DC bus capacitor C _B ' and the power semiconductor switch Q. One end ₁₃ of the power semiconductor switch and the other end Q ₁₁ is connected to the power semiconductor switch end Q ₁₂ of the power semiconductor switch and the other end Q ₁₂ is connected to the DC bus capacitor C _B 'and the other end of the power semiconductor switch and the other end Q ₁₄ of The connection point of the power semiconductor switch Q ₁₁ and the power semiconductor switch Q ₁₂ is connected to one end of the resonant circuit formed by the capacitor C' and the inductor L', and the other end of the resonant circuit is connected to one end of the primary coil of the transformer T', and the transformer T The other end of the primary coil is connected to the connection point of the power semiconductor switch Q ₁₃ and the power semiconductor switch Q ₁₄ , and one end of the DC bus capacitor C _B ' is the third end of the first power converter X ₃ , the DC bus capacitor The other end of C _B ' is the fourth end X ₄ of the first power converter, the rectifier bridge includes four rectifier diodes, and one end of the rectifier diode D ₁ ' is connected to the rectifier diode D ₃ ' The other end of the one end of the rectifying diode D ₁ 'and the other end is connected to a rectifier diode D _2' end, a rectifying diode D ₃ 'and the other end is connected to a rectifying diode D _4' end, a rectifying diode D ₂ 'is connected to a rectifying diode D ₄ 'At the other end, one end of the rectifier diode D ₁ ' is the fifth end X ₅ of the converter T', the other end of the rectifier diode D ₂ ' is the sixth end X ₆ of the converter, and the output ends of the transformer are respectively connected to the rectifier diode The connection point of D ₁ ' with the rectifier diode D ₂ ' and the connection point of the rectifier diode D ₃ ' and the rectifier diode D ₄ ', wherein the transformer T' may be a center tap transformer having two secondary coils and two secondary coils Connected in parallel, the transformer T' can also have a single secondary winding.

In the present embodiment, each of the power unit 70 of a third terminal of the full bridge resonant converter power unit X ₃ is a first end 70 of the X _1, a first full-bridge resonant converter fourth terminal X _{4 is} connected to the third end X _{3 of the} second full-bridge resonant converter, and so on, the fourth end X _{4 of} the M-1 full-bridge resonant converter is connected to the third end X of the M-th full-bridge resonant converter _3. The fourth end X ₄ of the Mth full bridge resonant converter is the second end X ₂ of the power unit 70. The fifth end X ₅ of each of the full bridge resonant converters in each of the power units 70 is connected together, and the sixth end X _{6 is} connected together.

In this embodiment, the local control signals corresponding to the power semiconductor switches of the same position of the full bridge circuit in each full bridge resonant converter are the same, that is, the local control signals are the same, for example, the power of the first full bridge circuit. The semiconductor switch Q ₁₁ , the power semiconductor switch Q _{21 of the} second full bridge circuit, and so on, until the local control signal corresponding to the power semiconductor switch Q _M1 of the Mth full bridge circuit is the same, that is, the same local control signal, that is, driving The circuit outputs corresponding drive signals Y ₁₁ , Y ₂₁ ... Y _{M1 are} identical, such that the upper power semiconductor switches Q ₁₁ , Q ₂₁ ... Q _{M1 are} simultaneously turned on and simultaneously turned off. Since the topology of each power converter 701 in the power unit 70 in this embodiment uses a full bridge resonant converter, one power unit 70 requires only a local controller 91, an optical fiber 94, and an auxiliary power source 93. In this embodiment, the power semiconductor switches at the same position of the full bridge resonant converters use the same local control signal, so that only one local control signal is required in one power unit 70.

Figure 13 is a block diagram of a modular power supply system in accordance with another embodiment of the present invention. As shown in FIG. 13, the topology of each of the power converters 701 in the same power unit 70 is a half bridge resonant converter. The half bridge resonant converter 701 includes a half bridge circuit, a resonant circuit, a transformer, and a rectifier bridge, the connection relationship of which is as shown in FIG. Taking the first half-bridge resonant converter 701 as an example, the half-bridge circuit includes two power semiconductor switches and one DC bus capacitor. One end of the power semiconductor switch Q ₁₁ is connected to one end of the DC bus capacitor C _B ', and the power semiconductor switch Q the other end ₁₁ is connected to the power semiconductor switch end Q _12, the power semiconductor switch other ends Q ₁₂ is connected to the DC bus capacitor C _B ', the power semiconductor switch Q ₁₁ of the power semiconductor switch Q is connected to the point ₁₂ is connected to the 'One end of the primary coil of the transformer T''L and the inductance' end of the resonance circuit composed of the other end of the resonance circuit of the capacitor C is connected to the transformer T, the other end of the primary coil is connected to the power semiconductor switch of another Q ₁₂ of At one end, one end of the DC bus capacitor C _B ' is the third end X ₃ of the first power converter, and the other end of the DC bus capacitor C _B ' is the fourth end X _{4 of the} first power converter, and the rectifier bridge includes four rectifying diodes, the rectifying diode D ₁ 'is connected to one end of the rectifying diode D _3' end, a rectifying diode D ₁ 'and the other end is connected to a rectifier diode D _2' end, a rectifying diode D ₃ 'of the other One end is connected to one end of the rectifier diode D ₄ ', the other end of the rectifier diode D ₂ ' is connected to the other end of the rectifier diode D ₄ ', and one end of the rectifier diode D ₁ ' is the fifth end X ₅ of the converter, and the rectifier diode D ₂ ' The other end of the converter is the sixth end X ₆ of the converter, and the output end of the transformer is respectively connected to the connection point of the rectifier diode D ₁ ' and the rectifier diode D ₂ ' and the connection point of the rectifier diode D ₃ ' and the rectifier diode D ₄ ', The transformer may be a center tapped transformer having two secondary windings, two secondary windings being connected in parallel, and the transformer may also have a single secondary winding.

In this embodiment, the third end X ₃ of the first half-bridge resonant converter in each power unit 70 is the first end X ₁ of the power unit 70, and the fourth end X of the first half-bridge resonant converter ₄ half-bridge resonant converter connected to the second terminal of the third X _3, and so on, the fourth terminal ₄ is connected to the M-X half-bridge resonant converter of a third terminal of the first X M-1 half-bridge resonant converter _3. The fourth end X ₄ of the Mth half-bridge resonant converter is the second end X ₂ of the power unit 70. The fifth ends X ₅ of all of the half-bridge resonant converters in each power unit 70 are connected together, and the sixth ends X _{6 are} connected together.

In this embodiment, the power semiconductor switches of the same position of the half bridge circuit in each half-bridge resonant converter have the same local control signal, that is, the local control signals are the same, for example, the power of the first half bridge circuit. The semiconductor switch Q ₁₁ , the power semiconductor switch Q _{21 of the} second half bridge circuit, and so on, until the local control signal corresponding to the power semiconductor switch Q _M1 of the Mth half bridge circuit is the same, that is, the corresponding drive of the drive circuit output The signals Y ₁₁ , Y ₂₁ ... Y _{M1 are} identical, such that the power semiconductor switches Q ₁₁ , Q ₂₁ ... Q _{M1 are} simultaneously turned on and off at the same time. Since the topology of each power converter 701 in the power unit 70 in this embodiment uses a half bridge resonant converter, one power unit 70 requires only a local controller 91, an optical fiber 94, and an auxiliary power source 93. In this embodiment, the power semiconductor switches at the same position of each half-bridge converter use the same local control signal, so that only one local control signal is required in one power unit 70.

Figure 14 is a block diagram of a modular power supply system in accordance with another embodiment of the present invention. As shown in FIG. 14, the topology of the M power converters 701 in the same power unit 70 employs a combination of a full bridge converter and a half bridge converter. The power converter 7011' of the full bridge converter includes four power semiconductor switches, and the half bridge converter 7012' includes two power semiconductor switches. In this embodiment, the specific connection relationship of the full-bridge converter is as shown in FIG. 7 , and the specific connection relationship of the half-bridge converter is shown in FIG. 8 , and details are not described herein again. Similarly, the two adjacent power converter wherein a fourth end X ₃ X ₄ of the third terminal 701 is connected with another, wherein M is a natural number greater than 1. Thus, the third end X _{3 of} the first power converter 701 is the first end X _{1 of} the power unit 70, and the fourth end X _{4 of the} first power converter 701 is connected to the second power converter 701. The third end X ₃ , and so on, the fourth end X _{4 of} the M-1th power converter 701 is connected to the third end X ₃ of the Mth power converter 701, and the fourth end of the Mth power converter 701 X _{4 is} the second end X _{2 of} the power unit 70.

In this embodiment, the local control signals corresponding to the power semiconductor switches of the same position of each full-bridge converter are the same, that is, the same local control signal, and the driving circuit outputs the corresponding driving signals, so that the power semiconductors of the same position are obtained. The switch is turned on and off at the same time. The local control signals corresponding to the power semiconductor switches of the same position of each half-bridge converter are the same, that is, the local control signals are the same, and the corresponding driving signals are output by the driving circuit, so that the power semiconductor switches of the same position are simultaneously turned on and simultaneously disconnect. Since the topology of the M power converters in the power unit 70 in this embodiment simultaneously uses a combination of a full bridge converter and a half bridge converter, one power unit 70 requires only one local controller 91, fiber 94, and auxiliary power source 93. . In this embodiment, the power semiconductor switches at the same position of the respective full-bridge converters use the same local control signal, and the power semiconductor switches at the same position of the respective half-bridge converters use the same local control signal, so that only one power unit 70 6 local control signals are required.

In other embodiments, the topology of the M power converters 701 of each power unit 70 in the modular power system uses both a full bridge converter, a half bridge converter, a neutral point controllable three level converter, and a diode. A combination of two or more of a clamp three-level converter, a flying capacitor three-level converter, a full-bridge resonant converter, and a half-bridge resonant converter. The local control signals corresponding to the power semiconductor switches of the same position in the same power structure of the M power converters 701 are the same, and the corresponding driving signals are output by the driving circuit, so that the power semiconductor switches of the same position are simultaneously turned on and simultaneously disconnected. .

As shown in FIGS. 6-14, each power unit 70 in the modular power supply system of the present embodiment may include: a plurality of driving circuits 702, the number of driving circuits in the power unit being equal to the power semiconductor switches in the power unit A quantity, wherein each of the driving circuits 702 is configured to be connected to a power semiconductor switch of the corresponding power converter 701, receive a local control signal output by the corresponding local controller 91, to output a driving signal to drive the corresponding power semiconductor switch Pass and disconnect.

Figure 15 is a block diagram of a modular power supply system in accordance with another embodiment of the present invention. As shown in FIG. 15, the M power converters 701 in the same power unit 70 are all neutral point controllable three-level converters. The power unit 70 may include 8×M drive circuits, each of which is configured to be connected to the power semiconductor switches Q ₁₁ , Q ₁₂ ... Q ₁₈ ... Q _M1 , Q _{M2 of the} power converter 701.. Corresponding one of .Q _M8 , each driving circuit receives a corresponding local control signal output by the local controller 91 to output driving signals Y ₁₁ , Y ₁₂ ... Y ₁₈ ... Y _M1 , Y _M2 .. A corresponding one of .Y _M8 drives the turn-on and turn-off of the corresponding power semiconductor switch.

It should be noted that the number of driving circuits included in one power unit in FIG. 6 to FIG. 15 is equal to the number of power semiconductor switches in the power unit, and each driving circuit is configured to be connected to a corresponding one of the power semiconductor switches of the power converter. One, each driving circuit receives a corresponding local control signal output by the local controller 91 to output a driving signal to drive the corresponding power semiconductor switch to be turned on and off.

Each of the drive circuits 702 of the modular power supply system of the present invention can be directly electrically connected to the corresponding local controller 91, or connected by magnetic isolation devices, or connected by optical isolation devices.

Figure 16 is a diagram showing the manner of connection between the local controller and the drive circuit of the present invention. As shown in FIG. 16, as an embodiment, the drive circuit 72 (702) is coupled to the local controller 91 via a magnetic isolation device T to transmit local control signals. The use of magnetic isolation devices has the advantages of high reliability, high performance, and low power consumption.

As an embodiment, the driver circuit 72 (702) and the local controller 91 can also be connected by an optical isolation device. The optical isolation device has the advantages of one-way signal transmission, complete electrical isolation between the input end and the output end, no influence of the output signal on the input end, strong anti-interference ability, stable operation, no contact, long service life and high transmission efficiency.

As an embodiment, drive circuit 72 (702) is directly electrically coupled to local controller 91.

Each of the drive circuits 72 (702) in the modular power supply system of the present invention may be identical to each other or different from each other.

As shown in FIGS. 6 to 15, each of the drive circuits 702 in the modular power supply system of the present embodiment is identical to each other.

Figure 17 is a block diagram of a modular power supply system in accordance with another embodiment of the present invention. As shown in FIG. 17, a power unit 701 of five H-bridge circuits is included in one power unit in the modular power supply system of the present embodiment. The drive circuit 721 of the four power converters 701 is different from the drive circuit 722 of the intermediate power converter 701.

Fig. 18 is a schematic view showing the driving mode of the driving circuit of the present invention. As shown, the driving circuit 722 includes a primary circuit 7221, circuit 7222, and the secondary magnetic separator means T ₁ 18, the primary circuit 7221 receives the signal output from the local controller local control 91, wherein the control signal includes only the local drive The component, the local control signal is a weak signal. The primary side circuit 7221 modulates the local control signal into a high-low level narrow pulse signal, wherein the high and low level narrow pulse signals include a driving logic pulse, and the narrow pulse signal is transmitted via a magnetic isolation device (for example, a high frequency isolation transformer) T _{1 .} The secondary circuit 7222, the secondary circuit 7222 restores the high and low voltage narrow pulse signals to a PWM signal and is amplified to output a driving signal to drive the on and off of the power semiconductor switch Q, wherein the narrow pulse signal only includes the driving logic pulse , for example, a PWM signal. The power unit 70 further includes a power supply circuit 7223 for supplying power to the primary side circuit 7221 and the secondary side circuit 7222. The power received by the power circuit 7223 may be from the auxiliary source 93, or other external power source, and the power circuit 7223 converts the received power into a voltage V ₁ that supplies power to the primary circuit 7221 and a voltage V ₂ that supplies power to the secondary side 7222, and The voltages V ₁ and V ₂ are isolated from each other. In other embodiments, the power supply circuit 7223 further includes a primary power supply circuit (not shown), an isolation transformer (not shown), and a secondary power supply circuit (not shown) that converts the received power supply into The primary side power supply supplies the primary side circuit 7221 with direct current V ₁ , and the primary side power supply circuit converts the received power supply into a power pulse, that is, the power supply pulse is transmitted to the secondary side power supply circuit through the isolation transformer, and then the power pulse is converted by the secondary side power supply circuit. The secondary side circuit 7222 is supplied with a direct current V ₂ for the secondary side power supply.

In order to simplify the driving circuit 722, the cost is saved, and the reliability of the driving circuit 72 is improved. In the present invention, the driving mode of each power converter can adopt "simple driving".

Fig. 19 is a schematic view showing another driving mode of the driving circuit of the present invention. As shown in FIG. 19, each of the drive circuits 721 of the modular power supply system of the present embodiment includes a primary side circuit 7211, a secondary side circuit 7212, and a magnetic isolation device (for example, an isolation transformer) T ₂ . The primary side circuit 7211 receives a local control signal, wherein the local control signal includes a driving component and a power component, the local control signal is a strong signal, and the primary side circuit 7211 modulates the local control signal into a positive and negative narrow pulse signal Y _MN , via magnetic isolation The device T _{2 is} transmitted to the secondary circuit 7212, which demodulates the narrow pulse signal Y _MN into a drive signal to drive the on and off of the power semiconductor switch Q, wherein the positive and negative narrow pulse signal Y _MN includes drive logic Pulses and power pulses, the power semiconductor switch Q comprises, for example, a gate G, a collector C and an emitter E, the drive signal being output to the gate G of the power semiconductor switch. The driving method described in FIG. 19 is "simple driving". This "simple driving" eliminates a large number of power supply circuits, so that the device of the driving circuit 721 is reduced a lot, the structure of the entire driving circuit 721 is simplified, and power consumption is reduced. Small, reliability has been improved.

Figure 20 is a circuit diagram of a driving circuit of one embodiment of the present invention. Figure 20 is based on Figure 19 and is an embodiment of the secondary side circuit of the drive circuit of Figure 19. Figure 21 is a timing chart of a driving circuit of one embodiment of the present invention. As shown in FIG. 20, the driving circuit of the present invention mainly comprises a magnetic isolation device T ₂ and a bidirectional voltage regulator W, and other resistors R ₁₁ , R ₁₂ , R ₁₃ , R, R ₂₁ , R ₂₂ , R ₂₃ , gate The pole capacitance C _GE , the diodes D ₁₁ , D ₂₁ , the Zener diodes W ₁ , W ₂ and the switching tubes M ₁ and M ₂ are auxiliary elements, the connection relationship of which is as shown in FIG.

Referring to FIG. 20 and FIG. 21, the local control signal PWM sent by the local controller 91 is modulated by the primary side circuit to form a positive and negative pulse signal Y _MN , as shown by Y _NM in FIG. 21 . The positive and negative pulse signals Y _NM are transmitted to the secondary circuit via a magnetic isolation device (for example, an isolation transformer) T ₂ , and the switching transistors M ₁ and M _{2 are} activated to charge and discharge the IGBT gate capacitance C _{GE to} form a driving power semiconductor switch. The waveforms of the required drive signals V _GE , V _GE are substantially similar to the local control signals PWM, as shown in FIG. In order to reduce the magnetic core of the magnetic isolation device, that is, the isolation transformer T ₂ , and to make the core unsaturated, the width of the refresh pulse of the positive and negative pulse signals Y _NM may be only a few _μs . Taking the gate-emitter voltage V _GE of the power semiconductor switch Q as positive, the positive pulse of several _μs charges the gate capacitor C _GE once, so that the driving signal V _{GE can} reach the gate of the power semiconductor switch. Turn on the voltage, for example +15V. However, to maintain the power semiconductor turn-on, the positive pulse required may be several tens of μs to hundreds of μs or even longer. Therefore, if there is no refresh pulse, the gate capacitance C _GE will slowly discharge and the driving signal V _{GE will} gradually decrease. The gate turn-on voltage required for the normal turn-on of the power semiconductor switch is not reached, so the refresh pulse is required to charge the gate capacitance C _GE at intervals to maintain the drive signal V _GE at the normal gate turn-on voltage. As for the refresh pulse interval, it is mainly determined by the discharge time constant of the gate capacitance C _GE . The principle is that the V _{GE does} not drop too much before the next refresh pulse. For example, the drive signal V _GE cannot be low before the next refresh pulse arrives. At 14V.

The local control signal received by the driving circuit of FIG. 20 includes a driving logic pulse and a power pulse, so that the driving circuit does not need an external power supply, and does not need to amplify the local control signal, which saves a lot of relative to the driving circuit of FIG. The power supply circuit reduces the number of devices of the driving circuit 721, the structure of the entire driving circuit 721 is simplified, the power consumption is reduced, and the reliability is improved.

In the above embodiment of the present invention, as shown in FIGS. 6-15, each of the driving circuits 702 may employ the driving circuit described in FIG. 19, and the local control signals transmitted by the magnetic isolation device include driving logic pulses and power pulses.

In other embodiments, as shown in FIGS. 6-15, each of the drive circuits 702 can employ the drive circuit depicted in FIG. 18, and the magnetic isolation device transmits drive logic pulses contained in the local control signals.

In the above embodiment of the present invention, as shown in FIG. 6 to 15, a drive circuit part of the driving circuit 702 described in FIG. 19 may be employed, and the power drive logic pulse magnetically isolated pulse T ₂ is transferred to local control device included in the signal ; and another part of the driver circuit of the driving circuit 702 described in FIG. 18, magnetic isolation local transmission device T ₁ controls the drive pulse signal included in the logic.

In the above embodiment of the present invention, as shown in FIG. 17, the driving circuit 721 can employ the driving circuit described in FIG. 19, the magnetic isolation device transmits the driving logic pulse and the power pulse included in the local control signal; and the driving circuit 722 adopts The drive circuit depicted in Figure 18, the magnetic isolation device transmits drive logic pulses contained in the local control signal.

In the above embodiment of the present invention, as shown in FIG. 17, the driving circuit 722 can adopt the driving circuit described in FIG. 19, the magnetic isolation device transmits the driving logic pulse and the power pulse included in the local control signal; and the driving circuit 721 adopts The drive circuit depicted in Figure 18, the magnetic isolation device transmits drive logic pulses contained in the local control signal.

Figure 22 is a block diagram of a modular power supply system in accordance with another embodiment of the present invention. As shown in FIG. 22, one of the M power converters 701 in each power unit 70 in the modular power supply system of the present embodiment is a main power converter 7012, and the remaining M-1 are slave power converters. 7011, wherein the main power converter 7012 and the slave power converter 7011 have the same topology, and one of the power converters described in FIGS. 7-15 may be used, or the main power converter 7012 and the slave power converter 7011. The topology is different. The main power converter can adopt one of the power converters described in FIG. 7 to FIG. 15. The power converter can adopt another of the power converters described in FIG. 7 to FIG. . Correspondingly, one of the M driving circuits is the main driving circuit 722, and the remaining M-1 are the slave driving circuit 721, and the main driving circuit 722 is configured to drive the power semiconductor switch in the corresponding main power converter 7012 to be turned on and Disconnected, each slave drive circuit 721 is configured to drive the turn-on and turn-off of the power semiconductor switches in the corresponding slave power converter 7011.

As an embodiment, in the modular power supply system as shown in FIG. 22, the main drive circuit 722 is different from the slave drive circuit 721, and the main drive circuit 722 employs the drive circuit described in FIG. 18, and the magnetic isolation device transmits only local control. The drive logic pulses included in the signal; and each of the slave drive circuits 721 employs the drive circuit depicted in FIG. 19, the magnetic isolation device transmitting drive logic pulses and power pulses contained in the local control signals.

As another embodiment, the main driving circuit 722 is different from the slave driving circuit 721, and each of the slave driving circuits 721 adopts the driving circuit described in FIG. 18, and the magnetic isolation device transmits the driving logic pulses included in the local control signal; and the main driving circuit 722 employs the drive circuit depicted in Figure 19, which transmits drive logic pulses and power pulses contained in the local control signals.

As a further embodiment, the main driving circuit 722 is the same as the slave driving circuit 721, and the main driving circuit 722 and the slave driving circuit 721 both adopt the driving circuit described in FIG. 18, and the magnetic isolation device transmits the driving logic pulse included in the local control signal; Alternatively, the main drive circuit 722 and the slave drive circuit 721 both employ the drive circuit described in FIG. 19, and the magnetic isolation device transmits drive logic pulses and power pulses contained in the local control signal.

In the present embodiment, when the topologies of the main power converter 7012 and the slave power converter 7011 are the same, and the main power converter 7012 is centered in the power unit 70, the slave power converters 7011 are respectively distributed to the main power converter 7012. On both sides. The local control signal corresponding to the main power converter 7012 is independent of the local control signal corresponding to the slave power converter 7011, that is, the main power converter 7012 is independently controlled, and the slave power converter 7011 is commonly controlled, for example, by using a common driver. Thus, the local control signals corresponding to the power semiconductor switches at the same location in the power converter 7011 are the same, and the main power converter 7012 is locally controlled corresponding to the power semiconductor switches at the same location from the power converter 7011. The signals are not the same.

In other embodiments, the main power converter 7012 and the slave power converter 7011 are jointly controlled, for example, using a common drive mode, the main power converter 7012 and the corresponding local power transformer switch at the same position in the power converter 7011. The control signals are the same.

23 is a block diagram of a modular power supply system in accordance with another embodiment of the present invention. As shown in FIG. 23, at least one of the M power converters 701 in each of the power units 70 in the modular power supply system of the present embodiment is a master power converter 7012, and at least one is a slave power converter 7011. Where the main power converter 7012 and the slave power converter 7011 have the same topology, one of the power converters described in FIGS. 7-15, or the main power converter 7012 and the slave power converter 7011 The topology is different, and the main power converter can employ one of the power converters described in Figures 7-15, and the slave power converter can employ another of the power converters described in Figures 7-15. Accordingly, at least one of the M driving circuits is the main driving circuit 722, and at least one is the slave driving circuit 721, and each of the main driving circuits 722 is configured to drive the power semiconductor switches in the corresponding main power converter 7012 to be turned on. And disconnected, each slave drive circuit 721 is configured to drive the turn-on and turn-off of the power semiconductor switches in the corresponding slave power converter 7011.

As an embodiment, in the modular power supply system as shown in FIG. 23, the main drive circuit 722 is different from the slave drive circuit 721, and each of the main drive circuits 722 employs the drive circuit described in FIG. The drive logic pulses included in the control signal; and each of the slave drive circuits 721 employs the drive circuit depicted in FIG. 19, the magnetic isolation device transmitting drive logic pulses and power pulses contained in the local control signals.

As another embodiment, the main driving circuit 722 is different from the slave driving circuit 721, and each of the slave driving circuits 721 adopts the driving circuit described in FIG. 18, and the magnetic isolation device transmits the driving logic pulses included in the local control signal; and each main The drive circuit 722 employs the drive circuit depicted in FIG. 19, which transmits drive logic pulses and power pulses contained in the local control signals.

As still another embodiment, the main driving circuit 722 is the same as the slave driving circuit 721, and each of the main driving circuit 722 and each of the slave driving circuits 721 adopts the driving circuit described in FIG. 18, and the magnetic isolation device transmits the local control signal. The logic pulses are driven; or each of the main drive circuit 722 and each of the slave drive circuits 721 employs the drive circuit depicted in FIG. 19, the magnetic isolation device transmitting drive logic pulses and power pulses contained in the local control signals.

In the present embodiment, when the topologies of the main power converter 7012 and the slave power converter 7011 are the same, each of the main driving circuits 722 is identical to each of the slave driving circuits 721, and each of the main power converters 7012 and each of the slave powers The converters 7011 are controlled in common, for example, by a common drive mode, and each of the main power converters 7012 and the local control signals corresponding to the power semiconductor switches at the same position from the power converter 7011 are the same. In other embodiments, the main driving circuit 722 and the slave driving circuit 721 may be the same or different, and the local control signal corresponding to the main power converter 7012 is independent of the local control signal corresponding to the slave power converter 7011, that is, the main The power converter 7012 is independently controlled, and is controlled by the power converter 7011 in common, for example, using a common driving mode, so that the local control signals corresponding to the power semiconductor switches at the same position from the power converter 7011 are the same, the main power conversion The local control signal corresponding to the power semiconductor switch at the same location from the power converter 7011 is not the same.

Figure 24 is a block diagram of a modular power supply system in accordance with another embodiment of the present invention. As shown in FIG. 24, in each of the power units 70 in the modular power supply system of the present embodiment, the number of the main power converter 7012 and the slave power converter 7011 is two or more. Each of the main power converter 7012 and the slave power converter 7011 have the same topology, and one of the power converters described in FIGS. 7-14 can be used, and the main drive circuit 722 and the slave drive circuit 721 can be driven in the same manner. The method adopts the aforementioned "simple drive", as described in the foregoing FIG. 19, that is, the magnetic isolation device of each main drive circuit 722 and each of the magnetic isolation devices from the drive circuit 721 transmit the local control signals contained therein. Driving the logic pulse and the power pulse; or each of the magnetic isolation devices of the main drive circuit 722 and each of the slave drive circuits 721 adopt the drive circuit described in FIG. 18, and the main magnetic isolation device and the slave magnetic isolation device both transmit local control signals. Contains drive logic pulses.

As another embodiment, each of the main power converter 7012 and the slave power converter 7011 have the same topology, and one of the power converters described in FIGS. 7-14 can be used, the main driving circuit 722 and the slave driving circuit. 721 may be different, each main driving circuit 722 adopts the driving circuit described in FIG. 18, the main magnetic isolating device transmits driving logic pulses included in the local control signal, and each of the slave driving circuits 721 adopts the driving circuit described in FIG. Transmitting a drive logic pulse and a power pulse contained in the local control signal from the magnetic isolation device; or each of the main drive circuit 722 adopts the drive circuit described in FIG. 19, and the main magnetic isolation device transmits the drive logic pulse included in the local control signal and The power pulses, and each of the slave drive circuits 721 employs the drive circuit depicted in FIG. 18 to transfer the drive logic pulses contained in the local control signals from the magnetic isolation device.

In the present embodiment, when the topology of the main power converter 7012 and the slave power converter 7011 are the same, the local control signals corresponding to each of the main power converters 7012 are independent of each other and independent of the corresponding power converter 7011. The local control signals, that is, each of the main power converters 7012 are independently controlled, each of the slave power converters 7011 adopts a common driving mode, and thus the local corresponding to the power semiconductor switches at the same position in the power converter 7011 The control signals are the same, and each of the main power converters 7012 and the two local control signals corresponding to the power semiconductor switches at the same position in the power converter 7011 are not the same.

As an embodiment, when the topologies of the main power converter 7012 and the slave power converter 7011 are the same, the local control signals corresponding to each of the main power converters 7012 are the same, each corresponding to the local corresponding to the power converter 7011. The control signals are the same, and the main power converter 7012 and the local control signal corresponding to the slave power converter 7011 are not the same, that is, each main power converter 7012 adopts a common driving mode, and each slave power converter 7011 The common driving mode is also adopted, so that the local control signals corresponding to the power semiconductor switches at the same position in each main power converter 7012 are the same, each corresponding to the power semiconductor switch at the same position in the power converter 7011. The local control signals are the same.

As another embodiment, when the topologies of the main power converter 7012 and the slave power converter 7011 are the same, each of the main power converters 7012 and the local control signals corresponding to each of the slave power converters 7011 are the same, that is, Each of the main power converters 7012 and each of the slave power converters 7011 adopts a common driving mode, and the local power converter 7012 and the local control signals corresponding to the power semiconductor switches at the same position from the power converter 7011 are the same. .

In another embodiment, when the topology of the main power converter 7012 and the slave power converter 7011 are different, the local control signals corresponding to each of the main power converters 7012 are independent of each other and are independent of the slave power converter 7011. Corresponding local control signals, that is, each main power converter 7012 is independently controlled, and each slave power converter 7011 adopts a common driving mode, and thus corresponds to a power semiconductor switch at the same position in the power converter 7011. The local control signals are the same, and each of the main power converters 7012 and the two local control signals corresponding to the power semiconductor switches at the same position in the power converter 7011 are not the same.

As another embodiment, when the topology of the main power converter 7012 and the slave power converter 7011 are different, the local control signals corresponding to each of the main power converters 7012 are the same, each corresponding to the power converter 7011. The local control signals are the same, and the main power converter 7012 and the local control signal corresponding to the slave power converter 7011 are not the same, that is, each main power converter 7012 adopts a common driving mode, and each slave power conversion The controller 7011 also adopts a common driving manner, so that the local control signals corresponding to the power semiconductor switches at the same position in each main power converter 7012 are the same, each power semiconductor switch at the same position from the power converter 7011. The corresponding local control signals are the same.

Figure 25 is a block diagram of a modular power supply system in accordance with another embodiment of the present invention. Figure 25 is a further description of Figure 23, which has been described in Figure 23 and will not be described again. As shown in FIG. 25, each of the power units 70 in the modular power supply system of this embodiment may further include: a plurality of DC bus voltage clamping circuits 703, and the foregoing power converter 701 adopting a common driving mode. Correspondingly, each of the DC bus voltage clamping circuits 703 is configured to be in parallel with the DC bus capacitance of the corresponding power converter 701 such that the DC bus voltage of the corresponding power converter 701 does not exceed a preset value. That is, the present invention incorporates a DC bus voltage control link in the power converter 701 of each of the power units 70 in the modular power system. In order to ensure reliable operation of the power converter 701, it is necessary to control the bus voltage in the power converter 701 within an appropriate range. The bus voltage control mode can be implemented by hardware or by software.

In this embodiment, when each of the slave power converters 7011 adopts a common driving mode, that is, the local control signals corresponding to the power semiconductor switches at the same position in the power converter 7011 are the same, each A DC bus voltage clamp circuit 703 is connected in parallel to the DC bus capacitor of the power converter 7011.

As an embodiment, when each of the main power converters 7012 and each of the slave power converters 7011 employs a common drive mode, that is, each of the main power converters 7012 and each of the slave power converters 7011 are at the same position. The local control signals corresponding to the power semiconductor switches are the same, and each of the main power converters 7012 and each of the DC bus capacitors of the power converter 7011 are connected in parallel with a DC bus voltage clamp circuit 703.

As an embodiment, the local control signals corresponding to the power semiconductor switches at the same location in each of the main power converters 7012 are the same, each corresponding to the local power semiconductor switch at the same location in the power converter 7011. The control signals are the same, and the main power converter 7012 and the local control signal corresponding to the slave power converter 7011 are not the same. Each DC power bus capacitor of the main power converter 7012 is connected in parallel with a DC bus voltage clamp circuit. Each DC bus voltage clamp circuit is connected in parallel with the DC bus capacitor of the power converter 7011, which can be the same as or different from the DC bus voltage clamp circuit connected in parallel with the DC bus capacitor of the main power converter.

As shown in FIG. 25, the DC bus voltage clamping circuit 703 is implemented by hardware to control the voltage across the DC bus capacitor C _B not to exceed a preset value.

When the DC bus voltage clamp circuit 703 is applied to the modular power supply system as shown in FIGS. 7, 8, and 12-14, the DC bus voltage clamp circuit 703 is connected to the DC bus capacitor C _{B of the} corresponding power converter 701. between the one end and the other end, while FIG. 9-11 and FIG. 15, the DC bus voltage clamping circuit 703 is connected to the power converter 701 corresponding to an end of the DC bus capacitor C ₁ and another capacitor C DC bus ₂ Between one end, so that the DC bus voltage of the corresponding power converter 701 does not exceed a preset value, wherein the DC bus voltage clamping circuit 703 is implemented by hardware.

Figure 26 is a block diagram of a modular power supply system in accordance with another embodiment of the present invention. FIG. 26 is a further description of FIG. 22, which has been described in FIG. 22, and will not be described again. As shown in FIG. 26, each of the power units in the modular power supply system of this embodiment may further include: M-1 DC bus voltage clamping circuits 703, and the aforementioned M-1 slave power converters 7011. One-to-one correspondence, wherein each of the DC bus voltage clamping circuits 703 is configured to be in parallel with the corresponding DC bus of the power converter 7011 such that the DC bus voltage of the corresponding slave power converter 7011 does not exceed a preset value.

In addition to using the DC bus voltage clamp circuit 703, the present invention also provides DC bus voltage control in a dynamically regulated manner. As shown in FIG. 26, the power unit 70 includes five cascaded H-bridge circuit-based power converters. It should be noted that the topology of the power converter in the power unit 70 can also be as shown in FIG. 7-15. The topology described. The intermediate power converter 7012 is independently controlled. Specifically, the DC bus voltage of the power converter 7012 obtained by the detection is compared with a preset value. If the DC bus voltage is higher than a preset value, the local controller 91 outputs a local control signal to control the power semiconductor switch of the H-bridge circuit of the power converter 7012 to be turned on or off to discharge its DC bus capacitor C _B if The DC bus voltage is lower than a preset value, and the local controller 91 outputs a local control signal to control the power semiconductor switch of the H-bridge circuit of the power converter 7012 to be turned on or off to charge its DC bus capacitor C _B , thereby making The DC bus voltage is controlled within a reasonable range.

As shown in FIG. 26, a total of four slave power converters 7011 are respectively distributed on both sides of the main power converter 7012, and four of the slave power converters can adopt the aforementioned common driving mode. The power semiconductor switches at the same location in each H-bridge circuit are controlled by drive signals corresponding to the same local control signal. In practical applications, due to the discreteness of the device, each power semiconductor switch controlled by the same local control signal cannot truly achieve simultaneous conduction and simultaneous disconnection, and the DC bus capacitance also has discreteness, resulting in DC bus voltages. There will be differences. After the DC bus voltage clamping circuit 703 is connected in parallel with the DC bus capacitor C _B of each of the slave power converters of the shared driving, the voltage of each DC bus capacitor C _B can be limited to a preset value, which can be guaranteed. The system operates reliably and reliably.

Figure 27 is a circuit diagram of a clamp circuit in accordance with one embodiment of the present invention. As shown in FIG. 27, each of the DC bus voltage clamping circuits 703 in the modular power supply system of the present embodiment includes a switch K, a resistor R, and a switch control circuit W _C . The switch K and the resistor R form a series branch, which is connected in parallel with the DC bus of the corresponding power converter 701. The switch control circuit W _{C is} connected to the control terminal of the switch K. When the DC bus voltage of the power converter 701 exceeds a preset value, the switch control circuit W _C outputs a switch control signal to turn on the switch K such that the DC bus of the power converter 701 is discharged through the series branch.

In Fig. 27, the switch control circuit W _C employs a transient suppression diode (TVS tube). The TVS tube is connected in series with a diode D. One end is connected to one end of the DC bus, and the other end is connected to the control end of the switch, wherein the diode D acts as a reverse protection. After the DC bus voltage of the power converter 701 exceeds the breakdown value of the TVS tube, the controllable switch K is turned on, so that the DC bus voltage on the DC bus capacitor C _B is discharged through the resistor R connected in series with the controllable switch K. . Until the DC bus voltage drops below the breakdown value of the TVS tube, the TVS tube returns to the off state, the controllable switch K is turned off, and the DC bus capacitor C _{B is} discharged. Therefore, the DC bus voltage clamping circuit 703 can limit the voltage of the DC bus capacitor of the power converter 701 to a preset value, that is, below the TVS breakdown value.

28 is a block diagram of a modular power supply system in accordance with another embodiment of the present invention. As shown in FIG. 28, each of the auxiliary power sources 93 in the modular power supply system of the present embodiment can be configured to take power from an external power source, and each of the auxiliary power sources 93 is connected to an external power source E _C , for example, from a commercial power source or an external power source. The circuit is powered, or the N auxiliary power sources 93 in the modular power system of the embodiment are in one-to-one correspondence with the N power units 70, and each of the auxiliary power sources 93 can be configured to take power from the corresponding power unit 70. Or each of the auxiliary power sources 93 of the modular power supply system of the present embodiment may be configured to take power from the DC bus capacitor C _B1 of any one of the corresponding power units 70 to obtain a DC bus capacitor C _{B1 .} The DC bus voltage on, or a portion of the auxiliary power source 93 in the modular power system of the present embodiment, may be configured to draw power from an external power source, and another portion of the auxiliary power source 93 may be configured to be from any of the corresponding power units 70. The DC bus capacitor C _{B1 of the} power converter 701 is energized to obtain the DC bus voltage on the DC bus capacitor C _B1 .

The invention can reduce the number of local controllers, optical fibers and auxiliary power sources by simplifying the structure by forming a plurality of power converters into one power unit and using a local controller, an optical fiber, and an auxiliary power source to control multiple power converters. Design, reduce costs and improve reliability.

The present invention simplifies the control circuit by sharing the power semiconductor switches at the same location of the power converters in the power unit with a local control signal.

The invention is applicable to the topology of all AC/DC, DC/AC, DC/DC power converter connections and is widely used.

The exemplary embodiments of the present invention have been particularly shown and described above. It is to be understood that the invention is not limited to the details of the details of the embodiments of the invention. Finally, it should be noted that the above embodiments are merely illustrative of the technical solutions of the present invention, and are not intended to be limiting; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art will understand that The technical solutions described in the foregoing embodiments may be modified, or some or all of the technical features may be equivalently replaced; and the modifications or substitutions do not deviate from the technical solutions of the embodiments of the present invention. range.

Claims (26)

A modular power system configured to include: a main controller configured to output a main control signal; N local controllers, wherein each of the local controllers is configured to receive the main control signal to output at least one local control signal; N power units, one-to-one corresponding to the N local controllers, wherein each of the power units includes a first end and a second end, and the second end of each of the power units is connected to an adjacent one The first end of one of the power units, each of the power units being configured to include M power converters, wherein each of the power converters includes a third end and a fourth end, each of the power The fourth end of the converter is coupled to the third end of an adjacent one of the power converters, and the third end of the first one of the power converters is the first of the power units And at one end, the fourth end of the Mth power converter is the second end of the power unit, and each of the power converters is configured to be output according to a corresponding local controller The local control signal operates, wherein N and M are both natural numbers greater than 1, wherein the power semiconductor switches controlling the same position in at least two of the M power converters are simultaneously turned on and simultaneously turned off The local control signals are the same. The modular power supply system of claim 1 configured to further include: N auxiliary power sources are in one-to-one correspondence with the N local controllers, wherein each of the auxiliary power sources is configured to provide power to a corresponding local controller. The modular power supply system of claim 2 wherein said N auxiliary power sources are configured to draw power from an external power source or to draw power from a corresponding one of said power units. The modular power supply system of claim 1 wherein said power converter is any one of an AC/DC converter, a DC/AC converter, and a DC/DC converter. The modular power system of claim 1 wherein the topologies of said M power converters are all identical or partially identical. The modular power supply system according to claim 5, wherein the topology of the M power converters in each of the power units is a full bridge converter, a half bridge converter, and a neutral point controllable three One of a flat converter, a diode clamped three-level converter, a flying capacitor three-level converter, a full-bridge resonant converter, and a half-bridge resonant converter. The modular power supply system according to claim 5, wherein the topology of said M power converters in each of said power units is a full bridge converter, a half bridge converter, and a neutral point controllable three level A combination of two or more of a converter, a diode clamped three-level converter, a flying capacitor three-level converter, a full-bridge resonant converter, and a half-bridge resonant converter. The modular power supply system of claim 5 wherein each of said power units further comprises: M driving circuits, one-to-one corresponding to the M power converters, wherein each of the driving circuits is configured to be connected to a corresponding power semiconductor switch of the power converter, and receive a corresponding output of the local controller The local control signal outputs at least one driving signal to drive the turning on and off of the power semiconductor switch in the corresponding M power converters. The modular power supply system of claim 5 wherein each of said power units further comprises: a plurality of drive circuits, wherein the number of the plurality of drive circuits is equal to the number of power semiconductor switches in the power unit, each of the drive circuits being configured to be coupled to the corresponding power semiconductor switch of the power converter Receiving a corresponding local control signal output by the local controller to output a driving signal to drive the corresponding on and off of the power semiconductor switch. A modular power supply system according to claim 8 or 9, wherein each of said drive circuits is identical to each other or different from each other. A modular power supply system according to claim 8 or claim 9, wherein each of said drive circuits includes a first magnetic isolation device that transmits drive logic pulses and power pulses contained in said local control signal Or each of the drive circuits includes a second magnetic isolation device that transmits drive logic pulses included in the local control signal. A modular power supply system according to claim 8 or claim 9, wherein a portion of said drive circuit comprises a first magnetic isolation device, said first magnetic isolation device transmitting drive logic pulses and power pulses contained in said local control signal; Another portion of the drive circuit includes a second magnetic isolation device that transmits drive logic pulses included in the local control signal. A modular power supply system according to claim 5, wherein at least one of said M power converters is a main power converter, at least one is a slave power converter, and at least one of said M drive circuits is a main drive circuit At least one is a slave drive circuit configured to drive a power semiconductor switch in the corresponding main power converter to be turned on and off, the slave drive circuit being configured to drive the corresponding slave The power semiconductor switches in the power converter are turned on and off. The modular power supply system of claim 13 wherein said primary power converter and said slave power converter are controlled when said topology of said primary power converter is identical to said topology of said slave power converter The local control signals of the same position of the power semiconductor switch being simultaneously turned on and simultaneously turned off are the same. A modular power supply system according to claim 13 wherein said number of said at least one main power converter is one, and said number of said at least one slave power converters is M-1, said slave power converter being controlled The local control signals of the same position of the power semiconductor switch being simultaneously turned on and simultaneously turned off are the same. The modular power supply system according to claim 13, wherein said slave power converter is controlled when the number of said at least one main power converter is greater than or equal to 2 and the number of said at least one slave power converter is greater than or equal to two The local control signals of the same position of the power semiconductor switch being simultaneously turned on and simultaneously turned off are the same. The modular power supply system of claim 16 wherein said controlling said same position in said main power converter when said topology of said main power converter is different from said topology of said slave power converter The local control signals that are simultaneously turned on and simultaneously turned off by the power semiconductor switches are the same. A modular power supply system according to claim 16 wherein said power of said same position in said main power converter is controlled when said topology of said main power converter is identical to said topology of said slave power converter The local control signals that are simultaneously turned on and simultaneously turned off by the semiconductor switches are the same. A modular power supply system according to any one of claims 13 to 4, wherein said main drive circuit and said slave drive circuit each comprise a magnetic isolation device that transmits drive logic pulses contained in said local control signal and a power pulse; or the magnetic isolation device transmits a drive logic pulse included in the local control signal. A modular power supply system according to any of the preceding claims, wherein said main drive circuit comprises a main magnetic isolation device, said slave drive circuit comprising a slave magnetic isolation device, wherein said main magnetic isolation device transmits said local control signal a drive logic pulse included in the drive, the drive logic pulse and power pulse included in the local control signal being transmitted from the magnetic isolation device; or the main magnetic isolation device transmitting drive logic pulse and power included in the local control signal A pulse that transmits a drive logic pulse included in the local control signal from a magnetic isolation device. A modular power supply system according to claim 14 wherein each of said main drive circuit and each of said slave drive circuits includes a magnetic isolation device that transmits drive logic contained in said local control signal Pulse and power pulses, or the magnetic isolation device transmits only drive logic pulses contained in the local control signal. A modular power supply system according to any of claims 15-18, wherein said main drive circuit comprises a main magnetic isolation device, said slave drive circuit comprising a slave magnetic isolation device, wherein said main magnetic isolation device transmits said local a drive logic pulse included in the control signal, the drive logic pulse and power pulse included in the local control signal being transmitted from the magnetic isolation device, or the main magnetic isolation device transmitting a drive logic pulse included in the local control signal And a power pulse that transmits a drive logic pulse included in the local control signal from the magnetic isolation device. A modular power supply system according to any of claims 15-18, wherein each of said power units further comprises: a plurality of first DC bus voltage clamping circuits in one-to-one correspondence with the slave power converters, wherein each of the first DC bus voltage clamping circuits is configured to be coupled to a DC bus of a corresponding slave power converter The capacitors are connected in parallel such that the corresponding DC bus voltage of the slave power converter does not exceed a first predetermined value. The modular power supply system of claim 23 wherein each of said first DC bus voltage clamping circuits comprises: a switch, a resistor, and a switch control circuit, wherein the switch forms a series branch with the resistor, the series branch is coupled in parallel with the DC bus capacitor, and the switch control circuit is coupled to the control end of the switch when When the DC bus voltage exceeds the first predetermined value, the switch control circuit outputs a switch control signal to turn on the switch such that the DC bus capacitor is discharged through the series branch. A modular power supply system according to any one of claims 16-18, wherein each of said power units further comprises: a plurality of first DC bus voltage clamping circuits in one-to-one correspondence with the slave power converters, wherein each of the first DC bus voltage clamping circuits is configured to be coupled to a DC bus of a corresponding slave power converter The capacitors are connected in parallel such that the DC bus voltage of the corresponding slave power converter does not exceed a first preset value; a plurality of second DC bus voltage clamping circuits in one-to-one correspondence with the main power converter, wherein each of the second DC bus voltage clamping circuits is configured to be in parallel with a DC bus capacitance of a corresponding main power converter So that the corresponding DC bus voltage of the main power converter does not exceed a second preset value. The modular power supply system of claim 25 wherein Each of the first DC bus voltage clamping circuits includes: a switch, a resistor, and a switch control circuit, wherein the switch forms a series branch with the resistor, the series branch is coupled in parallel with the DC bus capacitor, and the switch control circuit is coupled to the control end of the switch when When the DC bus voltage exceeds the first predetermined value, the switch control circuit outputs a switch control signal to turn on the switch, so that the DC bus capacitor is discharged through the series branch; Each of the second DC bus voltage clamping circuits includes: a switch, a resistor, and a switch control circuit, wherein the switch forms a series branch with the resistor, the series branch is coupled in parallel with the DC bus capacitor, and the switch control circuit is coupled to the control end of the switch when When the DC bus voltage exceeds the second predetermined value, the switch control circuit outputs a switch control signal to turn on the switch such that the DC bus capacitor is discharged through the series branch.

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