TWI813418B - Electronic transformer and three-phase four-wire power system thereof - Google Patents

Abstract

An electronic transformer includes a first forward rectifier, a second forward rectifier, a third forward rectifier and a backward rectifier. The first forward rectifier is coupled between a first-phase power and a first output terminal. The second forward rectifier is coupled between a second-phase power and the first output terminal. The third forward rectifier is coupled between a third-phase power and the first output terminal. The backward rectifier is coupled between a neutral line and a second output terminal. The first forward rectifier, the second forward rectifier, and the third forward rectifier are configured to half-wave rectify the first-phase power, the second-phase power, and the third-phase power to generate rectified first-phase to third-phase power sources, and superimpose the rectified first-phase to third-phase power sources on the first output end to serve as an output voltage of the electronic transformer.

Description

Electronic transformer and its three-phase four-wire power supply system

The present disclosure relates to electronic transformers, and in particular, refers to an electronic transformer and its three-phase four-wire power supply system.

An electronic transformer or coil transformer is a device that combines power electronic conversion technology and high-frequency power conversion technology based on the principle of electromagnetic induction to convert electrical energy with one power characteristic into electrical energy with another power characteristic. However, in converting three-phase AC voltage to DC voltage, conventional coil-type transformers have shortcomings such as high heat consumption, high power consumption, difficulty in installation, low efficiency, and inconvenient transportation. In view of this, the industry is committed to developing a miniaturized electronic transformer that can replace the conventional coil-type transformer.

One aspect of the present disclosure is an electronic transformer, including a first forward rectifier, a second forward rectifier, a third forward rectifier and a reverse rectifier. The first forward rectifier is coupled between a first-phase power supply and a first output terminal; the second forward rectifier is coupled between a second-phase power supply and the first output terminal; the third forward rectifier is coupled between a second-phase power supply and the first output terminal. The forward rectifier is coupled between a third-phase power supply and the first output terminal; and the reverse rectifier is coupled between a neutral line and a second output terminal; wherein the first forward rectifier, the second The forward rectifier and the third forward rectifier are configured to perform half-wave rectification on the first phase power supply, the second phase power supply and the third phase power supply to generate a rectified first phase power supply, a rectified third phase power supply. The two-phase power supply and the rectified third-phase power supply, and the rectified first-phase power supply, the rectified second-phase power supply, and the rectified third-phase power supply are superimposed on the first output end, so as to as the output voltage of the electronic transformer.

Another aspect of the present disclosure refers to a three-phase four-wire power supply system, including a power supply, a load and the above-mentioned electronic transformer. The power supply is configured to provide a first-phase power, a second-phase power and a third-phase power, and includes a neutral wire; and the electronic transformer is coupled between the power supply and the load, configured To convert the first phase power supply, the second phase power supply and the third phase power supply into an output voltage to the load.

The disclosed electronic transformer and its three-phase four-wire power supply system respectively performs half-wave rectification on the three-phase power supply through three forward rectifiers to generate a distributed and balanced output current at the first output end. In addition, the return current generated by the load is rectified by the reverse rectifier and then returned to the power supply through the neutral line, so that a complete current loop is formed between the power supply, the electronic transformer and the load, and the forward output current and the reverse return current are The operation is symmetrical and balanced, which improves the operating efficiency of the three-phase four-wire power system. Therefore, the present disclosure solves the problem of certain components quickly becoming damaged due to unbalanced current distribution. Furthermore, the present disclosure does not need to be configured into a three-phase three-wire structure for use in subsequent-stage products, and the electronic voltage converter of the present disclosure is more streamlined in design than a traditional electronic transformer. The disclosed electronic transformer and its three-phase four-wire power supply system have the following advantages: (1) stable output voltage; (2) balanced output current distribution; (3) streamlined circuit design, smaller layout area and cost ; and (4) the operating temperature is stable and does not increase over time.

Embodiments of the present disclosure are discussed in detail below. It is to be appreciated, however, that the embodiments provide many applicable concepts that can be embodied in a wide variety of specific contexts.

Figure 1 is a schematic diagram of a three-phase four-wire power supply system (hereinafter referred to as the system) 1. System 1 includes a power supply VS, an electronic transformer 10 and a load LD. The power supply VS transmits the three-phase power R, S, and T to the electronic transformer 10 through three live wires respectively. The electronic transformer 10 rectifies the first phase power supply R, the second phase power supply S and the third phase power supply T through three bridge rectifiers respectively to supply power to the load LD. The electronic transformer 10 includes a bridge transformer circuit at the front stage and a six-phase inverter at the rear stage. In operation, before nodes L1, L2, and L3, the bridge transformer circuit is used to rectify and convert the first phase power supply R, the second phase power supply S, and the third phase power supply T; after the nodes L1, L2, and L3 , the six-phase inverter performs secondary rectification; the capacitor 15 is connected between the first output terminal OUT1 and the second output terminal OUT2 to store energy and filter the rectified voltage to smooth (ie, filter) the voltage is supplied to the load LD.

However, in the electronic transformer 10, the design of the bridge transformer circuit causes unbalanced voltage distribution. Specifically, the two bridge rectifiers receiving the first phase power supply R and the second phase power supply S are both connected to the node L1; the bridge rectifier receiving the third phase power supply T is connected to the node L2; and the neutral line N is directly connected. to node L3. Therefore, the conversion voltage from the first-phase power supply R and the second-phase power supply S is simultaneously transmitted to the six-phase inverter through the node L1; the conversion voltage from the third-phase power supply T is transmitted to the six-phase inverter through the node L2; and The neutral wire N is connected to the six-phase inverter through node L3, however the power supply VS does not provide any energy to the neutral wire N. When an unbalanced voltage distribution is passed to a six-phase inverter for rectification, an unbalanced current will be generated. As the operating time of the electronic transformer 10 continues to pass, certain components (such as the diode connected to the node L1 ) generate heat because they encounter large currents more frequently, causing certain components to be damaged faster than other components. In addition, the wiring of the three-phase power supply R, S, and T in the power system may not be connected in order. Therefore, the heating element when encountering high current is not fixed, making it difficult to troubleshoot future product problems.

FIG. 2 is a voltage waveform diagram of the three-phase power supplies R, S, T and nodes L1, L2, and L3 of the electronic transformer 10 of FIG. 1 . The three-phase power sources R, S, and T are AC voltages of equal magnitude, frequency, and phase difference of 120 degrees. The line voltage may be, for example, 380 volts, and the phase voltage may be, for example, 220 volts, but is not limited thereto. Since the converted voltages from the first-phase power supply R and the second-phase power supply S are transmitted through the node L1 at the same time, the node L1 carries twice as much current stress. Since the converted voltage from the third phase power supply T is delivered through node L2, node L2 carries normal current stress. Since the power supply VS does not provide energy to the neutral line N, the voltage of the node L3 is the reverse voltage from the load LD. As can be seen from Figure 2, the voltages and currents distributed at nodes L1, L2, and L3 are unbalanced.

FIG. 3 is a current waveform diagram at the first output terminal OUT1 of the electronic transformer 10 of FIG. 1 . Currents I31, I32, and I33 are currents flowing from nodes L1, L2, and L3 through the diodes to the output terminal OUT1 respectively. At the first output terminal OUT1, the current I31 is generated according to the conversion voltage of the first phase power supply R and the second phase power supply S, so it has a two-phase sawtooth wave; the current I32 is generated according to the conversion voltage of the third phase power supply T. , so it has a one-phase sawtooth wave; and the current I33 is generated according to the conversion voltage of the neutral line N, so it is maintained at zero current without any one-phase sawtooth wave. From the above, it can be seen that the electronic transformer 10 has a problem of current imbalance in operation. When the electronic transformer 10 is used for a long time, specific components used to generate the current I31 generate heat and increase in temperature because they encounter large currents more frequently, causing the specific components to be damaged faster than other components. In addition, the electronic transformer 10 in FIG. 1 needs to be configured with many electronic components, so it requires a larger layout area.

FIG. 4 is a schematic diagram of a three-phase four-wire power supply system 4 according to an embodiment of the present disclosure. The three-phase four-wire power supply system 4 includes a power supply VS, an electronic transformer 40 and a load LD. The electronic transformer 40 is coupled between the power supply VS and the load LD, and is used to receive and rectify and convert the first phase power R, the second phase power S and the third phase power T from the power supply VS, and store them through the capacitor. It can supply power to the load LD after filtering.

Structurally, the electronic transformer 40 includes a first forward rectifier 41 , a second forward rectifier 42 , a third forward rectifier 43 , a reverse rectifier 44 and a capacitor 45 . The first forward rectifier 41 is coupled between the first phase power supply R of the power supply VS and the first output terminal OUT1; the second forward rectifier 42 is coupled between the second phase power supply S and the first phase power supply S of the power supply VS. between the output terminal OUT1; the third forward rectifier 43 is coupled between the third phase power supply T of the power supply VS and the first output terminal OUT1; and the reverse rectifier 44 is coupled between the neutral line N and the neutral line N of the power supply VS. between the second output terminal OUT2. The capacitor 45 is connected between the first output terminal OUT1 and the second output terminal OUT2. The second output terminal OUT2 is grounded.

In operation, the first forward rectifier 41 , the second forward rectifier 42 and the third forward rectifier 43 are configured to perform half-wave rectification on the first phase power supply R, the second phase power supply S and the third phase power supply T respectively. Generate rectified first-phase power supply R', rectified second-phase power supply S' and rectified third-phase power supply T', and convert the rectified first-phase power supply R', rectified second-phase power supply S' and the rectified third-phase power supply T' are superimposed on the first output terminal OUT1. The capacitor 45 is used to smooth (ie, filter) the voltage superimposed on the first output terminal OUT1 to serve as the output voltage Vdc and provide it to the load LD. Because the first forward rectifier 41, the second forward rectifier 42, and the third forward rectifier 43 respectively perform half-wave rectification on the first phase power supply R, the second phase power supply S, and the third phase power supply T, the current distribution is balanced. of. Therefore, the electronic transformer 40 and its three-phase four-wire power supply system 4 of the present disclosure solve the problem that certain components are quickly damaged because they encounter large currents more frequently (ie, unbalanced current distribution).

Then, after the load LD receives the output voltage Vdc, the return current Ire generated in the load LD further flows into the electronic transformer 40 through the second output terminal OUT2. The reverse rectifier 44 is configured to perform half-wave rectification on the return current Ire to generate a rectified return current Ire', which is transmitted back to the power supply VS through the neutral line N.

Simply put, the electronic transformer 40 performs half-wave conversion on the first phase power supply R, the second phase power supply S, and the third phase power supply T through the first forward rectifier 41, the second forward rectifier 42, and the third forward rectifier 43 respectively. Rectify, and superimpose the rectified first-phase power supply R', the rectified second-phase power supply S' and the rectified third-phase power supply T' at the first output terminal OUT1, and then smooth them through the capacitor 45 (i.e., Filter) The voltage superimposed on the first output terminal OUT1 is used as the output voltage Vdc and is provided to the load LD. Next, the reverse rectifier 44 performs half-wave rectification on the return current Ire generated by the load LD, and transmits the returned return current Ire' through the neutral line N back to the power supply VS.

To put it another way, the three-phase power supplies R, S, and T generated by the power supply VS are rectified respectively by the three forward rectifiers 41, 42, and 43 of the electronic transformer 40, and then collected into the output current Iout through the first output terminal OUT1. And flows into the load LD; then, the return current Ire generated by the load LD is rectified by the reverse rectifier 44 of the electronic transformer 40, and then returns to the power supply VS through the neutral line N. In this way, a complete current loop is formed between the power supply VS, the electronic transformer 40 and the load LD, and the operation of the forward output current Iout and the reverse return current Ire is symmetrical and balanced, which can improve the three-phase four-wire Operating efficiency of power system 4.

FIG. 5 is a schematic diagram of an electronic transformer 50 according to an embodiment of the present disclosure. The electronic transformer 50 can be used in the three-phase four-wire power supply system 4 of FIG. 4 and replaces the electronic transformer 40 . Structurally, the electronic transformer 50 includes a first forward rectifier 51 , a second forward rectifier 52 , a third forward rectifier 53 , a reverse rectifier 54 and a capacitor 55 . The first forward rectifier 51 includes diodes D1 and D2; the second forward rectifier 52 includes diodes D3 and D4; the third forward rectifier 53 includes diodes D5 and D6; and the reverse rectifier 54 includes diodes. D7, D8.

In this embodiment, each rectifier 51, 52, 53, 54 includes two diodes connected in parallel (for example, the diodes D1 and D2 in the rectifier 51 are connected in parallel). The cathode of each diode D1 and D2 in the first forward rectifier 51 is coupled to the first phase power supply R; the cathode of each diode D3 and D4 in the second forward rectifier 52 is coupled to the second phase power supply S; The cathode of each diode D5 and D6 in the third forward rectifier 53 is coupled to the third phase power supply T; and each of the first forward rectifier 51 , the second forward rectifier 52 and the third forward rectifier 53 The anodes of the pole bodies D1, D2, D3, D4, D5 and D6 are coupled to the first output terminal OUT1. The anode of each diode D7 and D8 in the flyback rectifier 54 is coupled to the neutral line N, and the cathode of each diode D7 and D8 in the flyback rectifier 54 is coupled to the second output terminal OUT2. The capacitor 55 is connected between the first output terminal OUT1 and the second output terminal OUT2. The operation modes of the electronic transformers 50 and 40 are similar and will not be described again.

It is worth noting that if each rectifier 51, 52, 53, 54 has K identical diodes D1, D2,..., DK, then the total of the K diodes D1, D2,..., DK connected in parallel The current I_TOTAL, total power P_TOTAL and total resistance R_TOTAL can be expressed by the following functions (1), (2), (3) (where "*" represents the multiplication sign): (1) (2) (3) The currents I_D1, I_D2,..., I_DK flowing through the diodes D1, D2,...DK respectively are all I_D, and the resistivities of the diodes D1, D2,..., DK are all R_D. In each rectifier, according to functions (1), (2), and (3), it can be known that the total power P_TOTAL is inversely proportional to the number K of secondary bodies (because the total current remains unchanged). In other words, the total power loss of the rectifier will decrease as the number K of diodes connected in parallel increases.

After K diodes are connected in parallel, the current flowing through each diode can be represented by the following table 1.

According to Table 1, it can be seen that the two currents corresponding to the number K of 5 and 6 differ by 3%, and the decrease in current is no longer significant. Taking into account specifications such as power consumption and layout area of the electronic transformer 50 , in some embodiments, the number K of diodes connected in parallel in each rectifier 51 , 52 , 53 , 54 may be 2 to 5. In addition, compared with the electronic transformer 10 shown in FIG. 1 that is configured with more electronic components (ie, three bridge rectifiers, six-phase inverter), the electronic transformer 40 shown in FIG. 4 is configured with fewer electronic components. components, so the layout area can be saved.

In one embodiment, each of the diodes D1, D2, D3, D4, D5, D6, D7, and D8 is a PN junction diode or a high-speed rectifier diode.

FIG. 6 is a waveform diagram of the output voltage Vdc of the electronic transformer 50 shown in FIG. 5 . Under the balanced voltage and current architecture, the output voltage is still relatively stable and has advantages over the traditional electronic transformer after two-stage rectification by selecting a suitable energy storage filter capacitor 55.

FIG. 7 is a waveform diagram of the output current Iout of the electronic transformer 50 shown in FIG. 5 , in which the currents I71, I72, and I73 are the currents output by the forward rectifiers 51, 52, and 53 respectively. The currents I71, I72, and I73 are gathered at the first output terminal OUT1 to form the output current Iout of the electronic transformer 50. It can be seen from FIG. 7 that because the three-phase power supplies R, S, and T are balanced and half-wave rectified by the forward rectifiers 51, 52, and 53, balanced distribution of currents I71, I72, and I73 can be generated. Therefore, the electronic transformer 50 of the present disclosure solves the problem that certain components are quickly damaged because they encounter large currents more frequently (ie, unbalanced current distribution).

FIG. 8 is a temperature change diagram of the electronic transformer 50 shown in FIG. 5 under operating conditions of 100% load and 150% load, in which curves 81 and 82 correspond to the temperature changes of 100% load and 150% load respectively. As can be seen from Figure 8, in addition to the instantaneous increase in temperature to the maximum temperature at the initial stage of power-on, as the operating time continues to pass, under full load (100% load) operating conditions, the temperature of the electronic transformer 50 can be maintained at a specific temperature. range (e.g. 71 degrees Celsius to 77 degrees Celsius) without gradually increasing over time. Furthermore, under overload (150% load) operating conditions, the temperature of the electronic transformer 50 can be maintained within a specific range (eg, 78 degrees Celsius to 84 degrees Celsius) without gradually increasing over time. Therefore, the electronic transformer 50 of the present disclosure has the advantage that the temperature is stable and does not increase over time.

The test conditions and results of the electronic transformer 50 can be summarized in Table 2 below. Table 2 Test conditions Output voltage maximum temperature ambient temperature 100% load 310V 81℃ 55℃ 150% load 310V 86℃ 55℃

FIG. 9 is a schematic diagram of an electronic transformer 90 according to an embodiment of the present disclosure. The electronic transformer 90 can be used in the three-phase four-wire power supply system 4 of FIG. 4 and replaces the electronic transformer 40 . Structurally, the electronic transformer 90 includes a first forward rectifier 91 , a second forward rectifier 92 , a third forward rectifier 93 , a reverse rectifier 94 and a capacitor 95 . The first forward rectifier 91 includes a diode D91; the second forward rectifier 92 includes a diode D92; the third forward rectifier 93 includes a diode D93; and the reverse rectifier 94 includes diodes D94, D95, and D96.

In some embodiments, the ratio of the number of diodes included in a forward rectifier and a reverse rectifier is 1:3. That is, the first forward rectifier, the second forward rectifier and the third forward rectifier each include K diodes connected in parallel, and the reverse rectifier includes 3 groups of K diodes connected in parallel. For example, in this embodiment, the forward rectifier 91 (or 92, 93) includes one diode D91 (or D92, D93), and the reverse rectifier 94 includes three diodes D94, D95, D96, so the diode The ratio of body numbers is 1:3. To put it another way, the number of diodes included in three forward rectifiers 91, 92, and 93 (i.e., the three forward-biased diodes D91, D92, and D93) is equal to the number of diodes included in one reverse rectifier 94. number (that is, three reverse-biased diodes D94, D95, and D96).

Under the structure of Figure 9, in the long term, the average current flowing through the three forward diodes D94, D95, and D96 is (1/3)*Iout, and the average current flowing through the three reverse diodes D94, D95 , the average current of D96 is (1/3)*Ire respectively. Therefore, the output current Iout is evenly distributed among the three forward-biased diodes D94, D95, and D96, and the return current Ire is also evenly distributed among the three reverse-biased diodes D94, D95, and D96. This solves the problem of specific components. The operating temperature of the electronic transformer 90 can be made more stable by more frequently encountering the problem of large currents (ie, unbalanced current distribution) causing certain components to be damaged quickly.

According to the embodiment of FIG. 5 , it can be seen that as the number K of diodes connected in parallel increases, the current of each diode decreases, so that the loss of each diode decreases. Therefore, in some embodiments, when the number K of diodes in parallel is 2, the forward rectifiers 91 , 92 , and 93 each include two parallel diodes, and the reverse rectifier 94 includes six parallel diodes. body, and so on.

FIG. 10 is a schematic diagram of an electronic transformer 99 according to an embodiment of the present disclosure. Electronic transformers 99 and 90 include the same components, and the connection relationships between the components are also the same. The difference between electronic transformers 99 and 90 is that diodes D91 and D94, D92 and D95, D93 and D96 are arranged adjacently. For each forward and reverse diode, the magnitude and direction of the forward current (1/3)*Iout and the reverse current (1/3)*Ire are opposite and equal. When a forward diode When placed adjacent to a reverse diode and its lines, a differential pair is formed, which can improve the energy transmission efficiency of the three-phase power supply.

FIG. 11 is a schematic layout diagram of the electronic transformer 99 and the three-phase four-wire power supply system 11 shown in FIG. 10 . The three-phase four-wire power supply system 11 includes a circuit board 110 formed on the XY plane; the circuit board 110 includes a first surface SF1 and a second surface SF2. Structurally, the power supply VS, the diode D91 of the forward rectifier 91 (the diodes D92 and D93 of the forward rectifiers 92 and 93 are not shown), the live wire used to transmit the first phase power R (where The live wire (not shown) for transmitting the second phase power S and the third phase power T and the load LD are disposed on the first surface SF1. The diode D94 of the reverse rectifier 94 (the diodes D95 and D96 are not shown) ) and the neutral line N are provided on the second surface SF2. A first through hole 111 is formed in the circuit board 110, extends along the Z direction, and is configured to connect the power supply VS and the neutral line N. A second through hole 112 is formed in the circuit board 110, extends along the Z direction, and is configured to connect the load LD and the neutral line N. In one embodiment, a connector can be provided on the circuit board 110 to connect to the power supply VS, and another connector can be provided on the circuit board 110 to connect to the load LD, so the power supply VS and the load LD can be external devices. .

In the structure of Figure 11, after the forward current (1/3)*Iout generated by the forward diode D91 is provided to the load LD through the live wire, the reverse current (1/3)*Ire generated by the load LD is provided to the reverse diode. pole body D94, and then returns to the power supply VS through the neutral line N. In this way, a complete current loop CL is formed between the power supply VS, the electronic transformer 99 and the load LD, and the operation of the forward output current and the reverse return current is symmetrical and balanced, which can improve the efficiency of the three-phase four-wire power supply. System 11 operating efficiency.

In one embodiment, the projection of the live wires for transmitting the three-phase power R, S, and T and the forward diodes (including D91, D92, and D93) disposed on the first surface SF1 on the XY plane are the same as those disposed on the first surface SF1. The projections of the neutral line N of the two surfaces SF2 and the reverse diodes (including D94, D95, and D96) on the XY plane overlap with each other. Under this structure, the area of the current loop CL is approximately the thickness of the circuit board 110 along the Z direction and the line length of the neutral line N (or live wire) along the X direction, so that the area of the current loop CL is approximately the minimum value, so that Minimize the electromagnetic radiation (i.e. energy loss) generated by the current loop CL. In other embodiments, when the circuit board 110 is a multi-layer board (for example, four layers, six layers or more), at least one of the live wires and the neutral wire N used to transmit the three-phase power supplies R, S, T It can be formed on the inner layer of the circuit board 110, which can further reduce the area of the current loop CL, or electromagnetic shielding can be achieved through the surface layer of the circuit board 110 to reduce the electromagnetic radiation (ie, energy loss) generated by the current loop CL.

In summary, the electronic transformer and its three-phase four-wire power supply system of the present disclosure perform half-wave rectification on the three-phase power supply through three forward rectifiers to generate distributed and balanced output current at the first output end. Therefore, the present disclosure solves the problem that certain components are quickly damaged because they encounter large currents more frequently (ie, unbalanced current distribution). In addition, the return current generated by the load is rectified by the reverse rectifier and then returned to the power supply through the neutral line, so that a complete current loop is formed between the power supply, the electronic transformer and the load, and the forward output current and the reverse return current are The operation is symmetrical and balanced, which improves the operating efficiency of the three-phase four-wire power system. The disclosed electronic transformer and its three-phase four-wire power supply system have the following advantages: (1) stable output voltage; (2) balanced output current distribution; (3) streamlined circuit design, smaller layout area and cost ; and (4) the operating temperature is stable and does not increase over time.

Although the present disclosure has been disclosed in the above embodiments, any person with ordinary knowledge in the relevant technical field may make some modifications and modifications without departing from the spirit and scope of the present disclosure. Therefore, the protection scope of the present disclosure shall be regarded as appended hereto. The scope of the patent application shall prevail.

1,4,5,11: Three-phase four-wire power system

10,40,50,90,99: Electronic transformer

41,51,91: First forward rectifier

42,52,92: Second forward rectifier

43,53,93: The third forward rectifier

44,54,94: reverse rectifier

15,45,55,95: capacitor

81,82:Curve

110:Circuit board

CL: current loop

D1,D2,D3,D4,D5,D6,D7,D8: diodes

D91,D92,D93,D94,D95,D96: Diode

Iout: output current

Ire,Ire’: return current

L1, L2, L3: nodes LD: load N: Neutral line OUT1: the first output terminal OUT2: The second output terminal R, R’: first phase power supply S, S’: second phase power supply T, T’: third phase power supply Vdc: output voltage VS: power supply

For a more complete understanding of the embodiments and their advantages, reference is now made to the following description taken in conjunction with the accompanying drawings. Figure 1 is a schematic diagram of a three-phase four-wire power supply system. Figure 2 is a three-phase input voltage and three node voltage waveform diagram of the electronic transformer of Figure 1. FIG. 3 is a waveform diagram of the output current at the first output end of the electronic transformer of FIG. 1 . FIG. 4 is a schematic diagram of a three-phase four-wire power supply system according to an embodiment of the present disclosure. FIG. 5 is a schematic diagram of an electronic transformer according to an embodiment of the present disclosure. FIG. 6 is an output voltage waveform diagram of the electronic transformer shown in FIG. 5 . FIG. 7 is an output current waveform diagram of the electronic transformer shown in FIG. 5 . Figure 8 is a temperature change diagram of the electronic transformer shown in Figure 5 under operating conditions of 100% load and 150% load. FIG. 9 is a schematic diagram of an electronic transformer according to an embodiment of the present disclosure. FIG. 10 is a schematic diagram of an electronic transformer according to an embodiment of the present disclosure. FIG. 11 is a schematic layout diagram of the electronic transformer and the three-phase four-wire power supply system 11 shown in FIG. 10 .

4: Three-phase four-wire power system

40:Electronic transformer

41: First forward rectifier

42: Second forward rectifier

43: The third forward rectifier

44:Reverse rectifier

45: Capacitor

Iout: output current

Ire,Ire’: return current

LD: load

N: Neutral line

OUT1: the first output terminal

OUT2: The second output terminal

R, R’: first phase power supply

S, S’: second phase power supply

T, T’: third phase power supply

Vdc: output voltage

VS: power supply

Claims (20)

An electronic transformer, including: a first forward rectifier coupled between a first phase power supply and a first output terminal; a second forward rectifier coupled between a second phase power supply and the first output between the terminals; a third forward rectifier, coupled between a third-phase power supply and the first output terminal; and a reverse rectifier, coupled between a neutral line and a second output terminal; wherein The first forward rectifier, the second forward rectifier and the third forward rectifier are configured to perform half-wave rectification on the first phase power supply, the second phase power supply and the third phase power supply to generate a rectified The first phase power supply, the rectified second phase power supply and the rectified third phase power supply, and the rectified first phase power supply, the rectified second phase power supply and the rectified third phase power supply are Power is superimposed on the first output terminal to serve as an output voltage of the electronic transformer. The electronic transformer of claim 1 further includes: a capacitor coupled between the first output terminal and the second output terminal, configured to store energy and filter the output voltage. The electronic transformer of claim 1, wherein the output voltage is supplied to a load to generate a return current at the second output terminal; and the inverse rectifier is configured to perform half-wave rectification of the return current to generate The rectified return current is rectified, and the rectified return current is transmitted to a power supply through the neutral line. The electronic transformer of claim 1, wherein the first forward rectifier, the second forward rectifier, the third forward rectifier and the reverse rectifier each include two to five diodes connected in parallel. The electronic transformer of claim 4, wherein: the cathode of each diode in the first forward rectifier is coupled to the first phase power supply, and the cathode of each diode in the second forward rectifier is coupled The second phase power supply, the cathode of each diode in the third forward rectifier is coupled to the third phase power supply, each of the first forward rectifier, the second forward rectifier and the third forward rectifier The anode of a diode is coupled to the first output terminal, the anode of each diode in the flyback rectifier is coupled to the neutral line, and the cathode of each diode in the flyback rectifier is coupled to the second output end. The electronic transformer as claimed in claim 1, wherein the proportion of the number of diodes contained in each of the first forward rectifier, the second forward rectifier, the third forward rectifier and the reverse rectifier It's 1:3. The electronic transformer of claim 6, wherein each diode in the first forward rectifier, the second forward rectifier and the third forward rectifier is adjacent to each diode in the reverse rectifier. settings. The electronic transformer of claim 6, wherein the first forward rectifier, the second forward rectifier and the third forward rectifier each include K diodes connected in parallel, and the reverse rectifier includes 3 groups of K diodes. Diodes connected in parallel, and K is a positive integer from 2 to 5. The electronic transformer of claim 8, wherein: the cathode of each diode in the first forward rectifier is coupled to the first phase power supply, and the cathode of each diode in the second forward rectifier is coupled The second phase power supply, the cathode of each diode in the third forward rectifier is coupled to the third phase power supply, and the first forward rectifier, the second forward rectifier and the third forward rectifier are The anode of each diode is coupled to the first output terminal, the anode of each diode in the flyback rectifier is coupled to the neutral line, and the cathode of each diode in the flyback rectifier is coupled to the second output terminal. A three-phase four-wire power supply system includes: a power supply configured to provide a first-phase power supply, a second-phase power supply and a third-phase power supply, and including a neutral wire; a load; and an electronic transformer , coupled between the power supply and the load, including: a first forward rectifier, coupled between the first phase power supply and a first output terminal; a second forward rectifier, coupled to The second phase power supply and the first output between the output terminals; a third forward rectifier coupled between the third phase power supply and the first output terminal; and a reverse rectifier coupled between the neutral line and a second output terminal; wherein The first forward rectifier, the second forward rectifier and the third forward rectifier are configured to perform half-wave rectification on the first phase power supply, the second phase power supply and the third phase power supply to generate a rectified The first phase power supply, the rectified second phase power supply and the rectified third phase power supply, and the rectified first phase power supply, the rectified second phase power supply and the rectified third phase power supply are Power is superimposed on the first output terminal to serve as an output voltage of the electronic transformer. As in the three-phase four-wire power supply system of claim 10, the electronic transformer further includes: a capacitor, coupled between the first output terminal and the second output terminal, configured to store energy and filter the output voltage. The three-phase four-wire power supply system of claim 10, wherein the output voltage is supplied to the load to generate a return current at the second output terminal; and the reverse rectifier is configured to perform half-wave rectification of the return current to generate The rectified return current is rectified, and the rectified return current is transmitted to the power supply through the neutral wire. The three-phase four-wire power supply system as described in claim 10, which The first forward rectifier, the second forward rectifier, the third forward rectifier and the reverse rectifier each include two to five diodes connected in parallel. The three-phase four-wire power supply system of claim 13, wherein: the cathode of each diode in the first forward rectifier is coupled to the first-phase power supply, and each diode in the second forward rectifier The cathode of each diode in the third forward rectifier is coupled to the second phase power supply, the cathode of each diode in the third forward rectifier is coupled to the third phase power supply, the first forward rectifier, the second forward rectifier and the third forward rectifier The anode of each diode in the rectifier is coupled to the first output terminal, the anode of each diode in the flyback rectifier is coupled to the neutral line, and the cathode of each diode in the flyback rectifier is coupled to the first output terminal. the second output terminal. The three-phase four-wire power supply system as claimed in claim 10, wherein each of the first forward rectifier, the second forward rectifier, the third forward rectifier and the diode included in the reverse rectifier The ratio of numbers is 1:3. The three-phase four-wire power supply system as claimed in claim 15, wherein each diode in the first forward rectifier, the second forward rectifier and the third forward rectifier is connected to each diode in the reverse rectifier respectively. The polar bodies are arranged adjacent to each other. A three-phase four-wire power supply system as described in claim 15, which The first forward rectifier, the second forward rectifier and the third forward rectifier all include K diodes connected in parallel, and the reverse rectifier includes 3 groups of K diodes connected in parallel, and the number K is a positive integer from 2 to 5. The three-phase four-wire power supply system of claim 17, wherein: the cathode of each diode in the first forward rectifier is coupled to the first-phase power supply, and each diode in the second forward rectifier The cathode of each diode in the third forward rectifier is coupled to the second phase power supply, the cathode of each diode in the third forward rectifier is coupled to the third phase power supply, and the first forward rectifier, the second forward rectifier and the third forward rectifier The anode of each diode in the forward rectifier is coupled to the first output terminal, the anode of each diode in the reverse rectifier is coupled to the neutral line, and the cathode of each diode in the reverse rectifier is coupled to the neutral line. Connect to the second output. The three-phase four-wire power supply system of claim 15 further includes a circuit board formed on a plane formed by a first direction and a second direction, the circuit board includes: a first surface, The power supply, the first forward rectifier, the second forward rectifier and the diodes of the third forward rectifier, for transmitting the first phase power, the second phase power and the third phase power. The live wire and the load are arranged on the first surface; and a second surface, the diode of the reverse rectifier and the neutral wire are arranged on the second surface; Wherein the live wires used to transmit the first phase power, the second phase power and the third phase power and the diodes of the first forward rectifier, the second forward rectifier and the third forward rectifier are on the plane The projection on this plane overlaps with the projection of the neutral line and the diode of the flyback rectifier on this plane. The three-phase four-wire power supply system of claim 19, wherein: a first through hole is formed in the circuit board and extends along a third direction, configured to connect the power supply and the neutral line; and A second through hole is formed in the circuit board and extends along the third direction, configured to connect the load and the neutral line.

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