WO2019187439A1 - Current reduction device and current reduction method - Google Patents

Abstract

This current reduction device comprises: a first switching element that is disposed in a pathway joining an interrupter connected to a DC overhead wire and a filter reactor connected to a power conversion device, and that supplies electric power from the DC overhead wire to the filter reactor through an ON operation; and a plurality of current reduction means that are connected in parallel to the first switching element during the ON operation of the first switching element, and that form a bypass pathway guiding current from the DC overhead wire to the filter reactor and reduce the current in the bypass pathway during an OFF operation of the first switching element; the plurality current reduction means incrementally reducing overcurrent that occurs in the DC overhead line due to malfunction or a ground fault of the power conversion device.

Description

Current reducing device and current reducing method

The present invention relates to a current reducing device and a current reducing method.

The electric power converter and filter reactor, which are electric components for driving railway vehicles, are mounted under the vehicle floor. In recent years, in order to improve the maintainability of vehicles, mounting of monitoring devices for grasping deterioration / failure of vehicle equipment and facilities has been studied. Since the space under the floor of the vehicle is limited, it is necessary to reduce the size of the drive electrical component in order to newly install these monitoring devices in the vehicle. In the power converter, an IGBT (Insulated Gate Bipolar Transistor) and a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), which are voltage-driven power semiconductors, are applied. Since power semiconductors such as IGBTs and MOSFETs can reduce switching loss by a high-speed switching operation, the cooler of the power converter can be downsized.

To reduce the size of the filter reactor, it is effective to reduce its inductance value. However, when the inductance value is reduced, the current per unit time flowing from the overhead line increases when the power conversion device fails or a ground fault occurs. Normally, this large current was interrupted by a mechanical device such as a high-speed circuit breaker. However, if the inductance value is reduced, the current per unit time increases. There is concern about exceeding the current. Therefore, by combining a semiconductor current reducer and a mechanical circuit breaker, it is possible to reduce and shut off a large current at a higher speed than a conventional mechanical circuit breaker, and to reduce and shut off the inductance value of the filter reactor. It has been studied to achieve both current reduction.

There is JP-A-2004-96877 (Patent Document 1) as background art in this technical field. In this publication, “a pantograph supplied with power from an overhead wire, a contactor connected to the pantograph and blocking the overhead power supplied from the pantograph, and an overhead wire power supplied via the contactor in three phases. An inverter for converting to AC power, a first resistor connected in series with the contactor, a second resistor connected in series with the first resistor, and having a higher resistance value than the first resistor; A first switching element connected in parallel to a series circuit composed of the first resistor and the second resistor, and a second switching element connected in parallel to the second resistor, The power supply device for an electric vehicle is described (see abstract).

JP 2004-96877 A

In Patent Document 1, when the switching element is turned off in order for the semiconductor current reducing device to reduce a large current, the large current flows through the current reducing resistor, so that an excessive surge voltage is generated and the switching element is destroyed. In order to suppress the surge voltage, it is effective to lower the resistance value of the current reducing resistor. On the other hand, since the current continues to flow through the current reducing resistor of the semiconductor current reducing device from when the current is reduced by the semiconductor current reducing device until the mechanical circuit breaker operates, the power consumption of the current reducing resistor increases. In order to reduce the power consumption, it is effective to increase the resistance value of the current reducing resistor. That is, suppression of the surge voltage during current reduction and reduction in power consumption are in a trade-off relationship with the resistance value of the current reduction resistance.

An object of the present invention is to achieve both suppression of a surge voltage of a switching element and reduction of power consumption of a current reducing resistor at the time of current reduction.

In order to solve the above problems, the present invention is arranged in a path connecting a current breaker connected to a DC overhead line and a filter reactor connected to a power converter, and is turned on from the DC overhead line by an ON operation thereof. The first switching element that supplies power to the filter reactor, and when the first switching element is turned on, is connected in parallel to the first switching element, and when the first switching element is turned off, Forming a bypass path for guiding current from a DC overhead line to the filter reactor, and a plurality of current reducing means for reducing the current in the bypass path, wherein the plurality of current reducing means is a failure of the power converter. Alternatively, an overcurrent generated in the DC overhead line due to a ground fault is reduced stepwise.

According to the present invention, it is possible to achieve both suppression of the surge voltage of the switching element and reduction of the power consumption of the current reducing resistor when the current is reduced.

It is the schematic of the electric vehicle in Example 1 of this invention. It is a circuit diagram of the electric motor drive system in Example 1 of this invention. It is an operation | movement waveform diagram of the semiconductor current reduction apparatus in Example 1 of this invention. It is a circuit diagram of the electric motor drive system in Example 2 of this invention. It is a circuit diagram of the electric motor drive system in Example 3 of this invention.

Hereinafter, examples will be described with reference to the drawings.

FIG. 1 is a schematic diagram of an electric vehicle according to Embodiment 1 of the present invention. In FIG. 1, during power running for accelerating an electric vehicle, electric power is supplied to a vehicle 8 from an overhead line (DC overhead line) 1 that is a power source via a current collector 7. The supplied power is subjected to DC-AC power conversion through the current breaker 11, the semiconductor current reducing device 10, the filter reactor 9, and the power conversion device 6, and the electric motor 5 is driven by the converted AC power. By driving the electric motor 5, the vehicle 8 moves forward by rotating the wheel 3. The electric motor 5 may be either an induction motor or a permanent magnet synchronous motor.

When regenerating to decelerate an electric vehicle, the power flow is opposite to that during powering. That is, the electric motor 5 operates as a generator, and after AC / DC power conversion is performed by the power converter 6, the filter 5, the semiconductor current reducer 10, the current disconnector 11, and the current collector 7 are connected to the overhead line 1. Electricity is regenerated. As an electrical ground, the negative voltage side of the power converter 6 is connected to the rail 2 via the wheel 3. The electric motor 5 is mounted on the carriage 4, and the carriage 4 supports the vehicle 8. Hereinafter, the voltage of the overhead wire 1 will be described as a direct current 1500V as an example.

FIG. 2 is a circuit diagram showing the overall configuration of the motor drive system according to the first embodiment of the present invention. In FIG. 2, the motor drive system for driving the motor 5 includes a power converter 6, a filter reactor 9, a semiconductor current reducer 10, a current breaker 11, a current sensor 12, and a control circuit 13. The power conversion device 6 includes a capacitor 105 and switching elements Q1 to Q6 as a DC-AC power conversion device. Switching elements Q1 and Q2 are connected in series to form a U phase, switching elements Q3 and Q4 are connected in series to form a V phase, and switching elements Q5 and Q6 are connected in series to form a W phase.

The diodes D1 to D6 are connected in parallel to the switching elements Q1 to Q6 so that the flow direction is opposite. Here, when the switching elements Q1 to Q6 are IGBTs, it is necessary to connect the diodes D1 to D6. However, when the switching elements Q1 to Q6 are elements having a body diode such as a MOSFET, the diodes D1 to D6 are connected. A MOSFET body diode can be used without connection. Further, a 2-in-1 element in which switching elements or diodes connected in series are mounted in the same package may be used.

The capacitor 105 removes noise flowing from the overhead wire 1 and smoothes the DC power. The switching elements Q1 to Q6 of the U-phase, V-phase, and W-phase of the power conversion device 6 control, for example, PWM (Pulse Width Modulation) to convert the DC power of the capacitor 105 into AC power and Supply.

The semiconductor current reducing device 10 is disposed in a path connecting the current disconnector 11 connected to the overhead wire 1 and cutting off the power from the overhead wire 1 and the filter reactor 9 connected to the power conversion device 6. The semiconductor current reducing device 10 includes switching elements Q7 to Q9, diodes D7 to D9 connected in parallel so that the flow directions of the switching elements Q7 to Q9 are opposite to each other, and current reducing resistors ( Resistors) 101 and 102 and charging resistors (resistors) 104.

The switching element Q7 is disposed in a path connecting the current breaker 11 connected to the overhead line 1 and the filter reactor 9 connected to the power conversion device 6, and the power of the overhead line 1 is generated by the ON operation. Then, it is supplied to the power converter 6 through the filter reactor 9. A series circuit including a current reducing resistor 101 and a charging resistor 104 is connected in parallel to the switching element Q7, and a series circuit including a current reducing resistor 102, a switching element Q8 and an antiparallel diode D8 is connected in parallel to the current reducing resistor 101. It is connected. A switching element Q9 and its antiparallel diode D9 are connected in parallel to the charging resistor 104.

The control signals from the control circuit 13 are supplied to the bases (gates) of the switching elements Q7 to Q9, and the on / off operation of the switching elements Q7 to Q9 is controlled by the control signal from the control circuit 13. The control circuit 13 outputs a control signal stepwise based on the detection signal of the current sensor 12. For example, the control circuit 13 outputs, to the switching elements Q7 to Q9, control signals (off signals) for turning off all the switching elements Q7 to Q9 when the capacitor 105 is initially charged. A control signal (ON signal) for turning on all Q9 is output to switching elements Q7 to Q9. Thereafter, when the current sensor 12 detects that the current from the overhead wire 1 has become an overcurrent (for example, a current of 2000 A or more), the control circuit 13 is turned off in response to the detection signal of the current sensor 12. The control signal (off signal) to be turned off is output to the switching element Q7, and then the control signal (off signal) to be turned off is outputted to the switching element Q8.

When the switching elements Q7 to Q9 are MOSFETs, the antiparallel diodes D7 to D9 may be body diodes. When a body diode is used, a diode chip is not required, and the switching elements Q7 to Q9 can be downsized. The switching element Q7 is connected to a cooler (not shown), and the heat generated by the switching element Q7 is cooled by the cooler.

The switching elements Q1 to Q10 may be voltage controlled switching elements such as MOSFETs and IGBTs, or current controlled switching elements such as thyristors. The diodes D1 to D10 may be PN diodes or SBDs (Schottky Barrier Diodes). The semiconductors of the switching elements Q1 to Q10 and the diodes D1 to D10 may be Si (silicon) or SiC (silicon carbide) or GaN (gallium nitride), which is a semiconductor having a wider band gap than Si.

AC power supplied from the power converter 6 to the electric motor 5 is supplied from the capacitor 105. In order to drive the power converter 6, the capacitor 105 needs to be initially charged. At the time of initial charge, switching elements Q7 to Q9 are all off. The charging current of the capacitor 105 flows from the overhead wire 1 through the current breaker 11, the current reducing resistor 101, the charging resistor 104, and the filter reactor 9. The capacitor 105 is charged by this current, and the voltage of the capacitor 105 rises to the voltage of the overhead line 1.

When the capacitor 105 is charged, all the switching elements Q7 to Q9 of the semiconductor current reducing device 10 are turned on. When the power conversion device 6 starts operation, DC power is supplied from the overhead wire 1 to the power conversion device 6 through the current breaker 11, the switching element Q 7, and the filter reactor 9.

Here, for example, when a ground fault occurs between the filter reactor 9 and the power converter 6, or when any of the U phase, V phase, and W phase of the power converter 6 is short-circuited, the overhead wire 1 A large current flows from. Since this large current is supplied from the substation connected to the overhead line 1, when the large current exceeds the allowable current of the substation, the supply of power from the substation is stopped.

If the wiring resistance of the overhead wire 1 and the filter reactor 9 is ignored, the slope of the large current increasing with time is the division of the voltage of the overhead wire 1 and the inductance value of the filter reactor 9. That is, as the inductance of the filter reactor 9 is smaller, the slope of increase of the large current with time becomes steeper, and thus it is necessary to cut off the large current at high speed.

The operation of the semiconductor current reducing device 10 and the current breaker 11 that cuts off a large current at high speed will be described using the operation waveform of FIG. The on / off state of the switching element Q7 is controlled by the control circuit 13 based on the signal from the current sensor 12. For example, if the detection threshold of a large current for determining a ground fault or a short-circuit failure of the power conversion device 6 is 2000A, the switching element Q7 is in an ON state when the current flowing through the switching element Q7 is less than 2000A. On the other hand, when the current detection value of the current sensor 12 is 2000 A or more, the control circuit 13 outputs a control signal (off signal) to the switching element Q7 so that the switching element Q7 is turned off.

Here, when a ground fault or a failure of the power converter 6 occurs at time t = t1, the current of the overhead wire 1 rises sharply. At time t = t2, when the current of the overhead line 1 reaches 2000A, which is a detection threshold for turning off the switching element Q7, as shown by the characteristic 201 in FIG. 3A, a control signal (off signal) Thus, the switching element Q7 is turned off. Here, since the switching element Q7 is a semiconductor, the time required for the turn-off operation is about several μs to several tens μs.

When the switching element Q7 is turned off, the switching elements Q8 and Q9 are turned on, so that a large current (overcurrent) is generated in parallel with the current reducing resistors 101 and 102 as shown by the characteristic 202 in FIG. It flows through the circuit and switching element Q9. At this time, a surge voltage calculated by multiplying the resistance values of the current reducing resistors 101 and 102 and a large current is generated between the collector and the emitter of the switching element Q7 as shown by the characteristic 204 in FIG. . For example, assuming that the resistance values of the current reducing resistors 101 and 102 are 4Ω and the detection threshold of a large current is 2000A, the surge voltage generated between the collector and the emitter of the switching element Q7 is 4000V (= 4Ω / 2 × 2000A). . That is, in order to reduce the surge voltage generated between the collector and emitter of the switching element Q7, it is effective to reduce the resistance values of the current reducing resistors 101 and 102.

The large current of the overhead wire 1 generated at time t = t2 is reduced by the current reduction resistors 101 and 102. The current of the overhead wire 1 after the current reduction is determined by the division of the DC voltage of the overhead wire 1 and the resistance value of the current reduction resistors 101 and 102 (the combined resistance value of the current reduction resistors 101 and 102). For example, if the DC voltage of the overhead wire 1 is 1500 V and the resistance values of the current reducing resistors 101 and 102 are 4Ω, the current of the overhead wire 1 after the current reduction is 750 A (= 1500 V / 4Ω / 2).

At time t = t3, the switching element Q8 is turned off. A control signal for turning off the switching element Q8 is generated based on a delay circuit added to the off signal of the switching element Q7 or a signal from the current sensor 12. When the switching element Q8 is turned off, between the collector and emitter of the switching elements Q7 and Q8, as shown by the characteristic 204 in FIG. 3D, calculation is performed by multiplying the resistance value of the current reducing resistor 102 and the current reducing current. Generated surge voltage. As described above, assuming that the resistance value of the current reducing resistor 102 is 4Ω and the current reducing current is 750A, the surge voltage generated between the collector and emitter of the switching elements Q7 and Q8 is 3000V (= 4Ω × 750A).

When the switching element Q8 is turned off, no current flows through the current reducing resistor 102, and the current in the overhead wire 1 is reduced by the current reducing resistor 101. At this time, the current of the overhead wire 1 after current reduction is determined by dividing the resistance value of the overhead wire 1 and the current reduction resistance 101. As described above, when the DC voltage of the overhead wire 1 is 1500 V and the resistance value of the current reducing resistor 101 is 4Ω, the current of the overhead wire 1 after the current reduction is 375 A (= 1500 V / 4Ω). Due to the effect of the present embodiment, the large current of the overhead wire 1 is reduced stepwise.

The breaker 11 is released at time t = t4, and the power supplied from the overhead wire 1 is cut off. From time t = t2 to time t = t4, the current in the overhead wire 1 is reduced by the current reducing resistors 101 and 102, and thus the current reducing resistors 101 and 102 generate losses. This amount of power consumption is obtained by multiplying the division of the square of the voltage of the overhead wire 1 and the resistance values of the current reducing resistors 101 and 102 by the time until the circuit breaker 11 operates. For example, if the DC voltage of the overhead line 1 is 1500 V, the resistance values of the current reducing resistors 101 and 102 are 4Ω, and the time between time t = t2 and time t = t3 is 10 ms, The total power consumption is 11250 J (= 1500 V ² / 2Ω × 10 ms) as shown by the characteristic 203 in FIG. Assuming that 90 ms is from time t = t3 to time t = t4, the power consumption of the current reducing resistor 101 during this period is 50625J (= 1500 V ² / 4Ω as shown by the characteristic 203 in FIG. 3C. × 90 ms). That is, in order to reduce the power consumption of the current reducing resistors 101 and 102, it is effective to increase the resistance values of the current reducing resistors 101 and 102. Note that the characteristics of the related art with respect to the characteristics 201 to 204 are the characteristics 301 to 304.

As described above, the reduction of the surge voltage between the collector and the emitter of the switching element Q7 generated at time t = t2 and the reduction of the power consumption of the current reducing resistors 101 and 102 generated from time t = t2 to time t = t4. There is a trade-off relationship. That is, if the resistance values of the current reducing resistors 101 and 102 are reduced to reduce the surge voltage of the switching element Q7, the power consumption of the current reducing resistors 101 and 102 increases, and the volume of the current reducing resistors 101 and 102 increases. growing. On the other hand, when the resistance value of the current reducing resistors 101 and 102 is increased in order to reduce the power consumption of the current reducing resistors 101 and 102, the surge voltage of the switching device Q7 increases, so that the rated voltage of the switching device Q7 is increased. The volume of the cooler increases as the conduction loss increases.

Therefore, in this embodiment, when the switching element Q7 is turned on, the current reducing resistors 101 and 102 are connected in parallel to the switching element Q7, and when the switching element Q7 is turned off, the current reducing resistors 101 and 102 and the switching element Q8 are connected. , Q9 forms a bypass path for guiding the current (overcurrent) from the overhead wire 1 to the power converter 6 through the filter reactor 9, and the resistance value is smaller than the resistance value of the current-reducing resistors 101 and 102 alone (synthesis) The overcurrent is reduced (first stage reduction) by the current-reducing resistors 101 and 102 having a small resistance value, and the surge voltage between the collector and the emitter of the switching element Q7 generated at time t = t2 is reduced. Further, at time t = t3, the switching element Q8 is turned off to remove the current reducing resistor 102 from the parallel connection with the switching element Q7, and the resistance value is larger than the combined resistance value of the current reducing resistors 101 and 102. The overcurrent is reduced only by the current resistor 101 (second stage current reduction), and the power consumption of the current reducing resistor 101 generated from time t = t2 to time t = t4 is reduced.

At this time, the current reducing resistors 101 and 102, the charging resistor 104, and the switching elements Q8 and Q9 are connected in parallel to the switching element Q7 when the switching element Q7 is turned on, and the large current from the overhead line 1 is turned on when the switching element Q7 is turned off. A bypass path is formed to lead current, for example, overcurrent generated in the overhead wire 1 due to a failure or ground fault of the power converter 6 to the power converter 6 via the filter reactor 9, and the current in the bypass path is reduced stepwise. A plurality of current reducing means are configured to flow. The current reducing resistor 101, the charging resistor 104, and the switching element Q9 are configured as a first current reducing means or a main current reducing means that is always connected in parallel to the switching element Q7 when the switching element Q9 is turned on. The current reducing resistor 102 and the switching element Q8 are connected to the switching element Q7 from the state of being connected in parallel to the switching element Q7 by the ON operation of the switching element Q8 when the switching element Q7 is OFF. Are configured as second current reducing means or auxiliary current reducing means from which the parallel connection is removed.

According to the present embodiment, by newly installing the switching element Q8 and the current reducing resistor 102, the resistance value of the resistor for reducing the overcurrent in two stages using the current reducing resistors 101 and 102 can be obtained. By being able to change, it becomes possible to achieve both reduction of the surge voltage of the switching element Q7 and reduction of the power consumption of the current reducing resistors 101 and 102.

Further, the characteristics 201, 202, and 203 in FIG. 3 indicate values smaller than the characteristics 301, 302, and 303 after the time t = t3. The characteristic 204 shows a smaller value than the characteristic 304 at time t = t2. That is, it can be seen from the characteristics of FIG. 3 that the present embodiment achieves both the reduction of the surge voltage of the switching element Q7 and the reduction of the power consumption of the current reducing resistors 101 and 102.

FIG. 4 is a circuit diagram of an electric motor drive system according to the second embodiment of the present invention. In the present embodiment, the operations of the power conversion device 6 and the electric motor 5 are the same as those in the first embodiment, and are omitted.

In the semiconductor current reducing device 10 of the second embodiment, in addition to the first embodiment, a series circuit of a current reducing resistor 103 and a switching element Q10 is connected in parallel to the current reducing resistor 101. Note that an antiparallel diode D10 is connected to the switching element Q10.

The on / off state of the switching element Q10 is a control signal generated from the control circuit 13 based on the detection value of the current sensor 12 or a control signal generated by adding a delay time to the off signal of the switching element Q8. Controlled by output. For example, a control signal (off signal) is input from the control circuit 13 to the switching element Q10 after 10 ms from the off signal of the switching element Q8. With this control signal, the switching element Q10 is turned off between time t = t3 and time t = t4, whereby the current of the overhead wire 1 is further reduced by the current reducing resistor 101. That is, at time t = t2, the switching element Q7 is turned off, and the current of the overhead wire 1 is reduced (first stage reduction) with the combined resistance value of the current reducing resistors 101, 102, 103, and then the time t At time t = t3, the switching element Q8 is turned off, and the current of the overhead wire 1 is reduced (second stage current reduction) with the combined resistance value of the current reducing resistors 101 and 103. From time t = t3 to time t = t4 During this period, the switching element Q10 is turned off, and the current of the overhead line 1 is further reduced (third stage reduction) by the current reduction resistor 101.

At this time, for example, if the total resistance value of the current reducing resistors 101 to 103 is 2Ω in accordance with the first embodiment, each of the current reducing resistors 101 to 103 is 6Ω. As a result, the surge voltage generated in the switching element Q7 at time t = t2 is 4000 V as in the first embodiment. On the other hand, when the switching element Q10 is turned off between time t = t3 and t = t4, the current of the overhead wire 1 after the current reduction becomes 250 A (1500 V / 6Ω). This current is lower than that in the first embodiment, and the total power consumption of the current reducing resistors 101 to 103 can be reduced.

At this time, the current reducing resistor 101 and the charging resistor 104 are configured as first current reducing means or main current reducing means that is always connected in parallel to the switching element Q7 by the ON operation of the switching element Q9. The current reducing resistor 102 and the switching element Q8 are connected to the switching element Q7 from the state of being connected in parallel to the switching element Q7 by the ON operation of the switching element Q8 when the switching element Q7 is OFF. Are configured as second current reducing means or auxiliary current reducing means from which the parallel connection is removed. When the switching element Q7 is turned off, the current reducing resistor 103 and the switching element Q10 are connected in parallel to the switching element Q7 by the switching element Q10 being turned on, and thereafter (the second current reducing means or the auxiliary current reducing means is connected). After being disconnected from the parallel connection with the switching element Q7), the switching element Q10 is configured as a third current reducing means or an auxiliary current reducing means in which the parallel connection with the switching element Q7 is disconnected by the off operation of the switching element Q10.

According to this embodiment, a series circuit of the current reducing resistor 102 and the switching element Q8 and a series circuit of the current reducing resistor 103 and the switching element Q10 are connected in parallel to the current reducing resistor 101 in a plurality of stages. The total power consumption of the current reducing resistors 101 to 103 can be further reduced while further suppressing the surge voltage of the switching element Q7. In Example 2, the resistance value of the current reducing resistor was switched in three stages by using the current reducing resistors 101 to 103 and the switching elements Q8 and Q10. However, the series circuit of the switching element and the current reducing resistor was reduced in current. The number of stages connected in parallel to the resistor 101 may be two or more. By making the series circuit of the switching element and the current reducing resistor into two or more stages, it is possible to further reduce the total power consumption of the current reducing resistors 101 to 103 while further suppressing the surge voltage of the switching element Q7. it can.

FIG. 5 is a circuit diagram of an electric motor drive system in Embodiment 3 of the present invention. In the present embodiment, the operations of the power conversion device 6 and the electric motor 5 are the same as those in the first embodiment, and are omitted.

The semiconductor current reducing device 10 shown in the third embodiment includes switching elements Q7 to Q9, antiparallel diodes D7 to D9, current reducing resistors 101 and 102, and a charging resistor 104. A series circuit of the current reducing resistor 101 and the switching element Q9 and a series circuit of the current reducing resistor 102 and the switching element Q9 and the charging resistor 104 are connected in parallel to the switching element Q7, respectively.

In the initial charging of the capacitor 105 before the power conversion device 6 starts operation, all the switching elements Q7 to Q9 are in the off state. That is, the charging current of the capacitor 105 flows from the overhead wire 1 through the current breaker 11 and the charging resistor 104.

The on / off states of the switching elements Q7 to Q9 due to the ground fault or the failure of the power converter 6 are the same as in the first embodiment. When the switching element Q7 is turned off to reduce the large current, the large current (overcurrent) flows through the current reducing resistors 101 and 102 and the charging resistor 104. In the first embodiment, the overcurrent is reduced by the current reducing resistors 101 and 102. On the other hand, in the third embodiment, the overcurrent is distributed and supplied to the current reducing resistors 101 and 102 and the charging resistor 104, and more resistors flow at the time of current reduction than in the first embodiment. Power consumption is distributed. For this reason, compared with the first embodiment, at least the number of resistors constituting the charging resistor 104 can be reduced, and the size of the resistor and the size of the entire device can be reduced.

At this time, the current reducing resistor 101, the charging resistor 104, and the switching element Q9 are configured as first current reducing means or main current reducing means that is always connected in parallel to the switching element Q7 when the switching element Q9 is turned on. The current reducing resistor 102 and the switching element Q8 are connected to the switching element Q7 from the state of being connected in parallel to the switching element Q7 by the ON operation of the switching element Q8 when the switching element Q7 is OFF. Are configured as second current reducing means or auxiliary current reducing means from which the parallel connection is removed.

According to the present embodiment, the same effects as in the first embodiment can be obtained, and the power consumption of the current reducing resistors 101 and 102 and the charging resistor 104 associated with the current reducing operation can be reduced as compared with the first embodiment. And the size of the resistor can be reduced.

In the third embodiment, the series circuit including the switching element and the current reducing resistor is parallel to the switching element Q7 in two stages. The circuit may have three or more stages.

In addition, this invention is not limited to the above-mentioned Example, Various modifications are included. For example, the control circuit 13 can be integrated with the semiconductor current reducing device 10. Further, a current reducing device including the current breaker 11 and the semiconductor current reducing device 10 is configured, or a current reducing device including the current disconnector 11, the semiconductor current reducing device 10 and the control circuit 13 is configured. You can also. At this time, as the control circuit 13, for example, after outputting a control signal (ON signal) for turning on the switching elements Q7, Q8, Q9, the detection output of the current sensor 12 for detecting the overcurrent generated in the overhead wire 1 is output. Based on this, it is possible to configure a control circuit that outputs a control signal (off signal) for turning off the switching element Q7 and then outputs a control signal (off signal) for turning off the switching element Q8.

For example, the control circuit 13 outputs a control signal (ON signal) for turning on the switching elements Q7, Q8, Q9, and Q10, and then detects the output of the current sensor 12 that detects an overcurrent generated in the overhead wire 1. , The control signal (off signal) for turning off the switching element Q7 is output, and then the control signal (off signal) for turning off the switching element Q8 is output. Thereafter, the switching element Q10 is turned off. It is possible to configure a control circuit that outputs a control signal (off signal).

The above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

Also, each of the above-described configurations, functions, etc. may be realized by hardware by designing a part or all of them, for example, by an integrated circuit. Each of the above-described configurations, functions, and the like may be realized by software by interpreting and executing a program that realizes each function by the processor. Information such as programs, tables, and files that realize each function is stored in memory, a hard disk, a recording device such as an SSD (Solid State Drive), an IC (Integrated Circuit) card, an SD (Secure Digital) memory card, a DVD ( It can be recorded on a recording medium such as Digital Versatile Disc).

1 overhead line, 2 rails, 3 wheels, 4 carts, 5 motors, 6 power converters, 7 current collectors, 8 vehicles, 9 filter reactors, 10 semiconductor current reducers, 11 current breakers, 12 current sensors, Q1 to Q10 Switching element, D1 to D10 diode, 101 to 103, current reducing resistance, 104 charging resistance, 105 capacitor

Claims (12)

A first line is arranged in a path connecting a current breaker connected to the DC overhead line and a filter reactor connected to the power converter, and supplies power from the DC overhead line to the filter reactor by the ON operation. A switching element;
A bypass path is formed that is connected in parallel to the first switching element when the first switching element is turned on, and that guides current from the DC overhead line to the filter reactor when the first switching element is turned off. A plurality of current reducing means for reducing current in the bypass path,
The plurality of current reducing means includes:
An overcurrent generated in the DC overhead line due to a failure of the power converter or a ground fault is gradually reduced. The current reducing device according to claim 1,
The plurality of current reducing means includes:
Main current reducing means connected in parallel to the first switching element;
One or more auxiliary current reducing means for removing the parallel connection with the first switching element from the state connected in parallel with the first switching element during the OFF operation of the first switching element And a current reducing device. The current reducing device according to claim 1,
The plurality of current reducing means includes:
First current reducing means connected in parallel to the first switching element;
A second current reducing means for removing the parallel connection with the first switching element from the state connected in parallel with the first switching element during the off operation of the first switching element; Prepared,
The first current reducing means includes
A circuit connected in parallel to the first switching element, the first series circuit including a first resistor and a second resistor, and a first circuit arranged in parallel to the second resistor Two switching elements, and the first resistor is connected in parallel to the first switching element by the ON operation of the second switching element,
The second current reducing means includes
A second series circuit including a third resistor and a third switching element; and the second series circuit is configured to turn on the third switching element when the first switching element is turned on. The first switching element and the first switching element are connected in parallel with each other, and after the first switching element is turned off, the third switching element is turned off. The current reducing device is characterized in that the parallel connection is removed. The current reducing device according to claim 1,
The plurality of current reducing means includes:
First current reducing means connected in parallel to the first switching element;
A second current reducing means and a third current reducing means for removing the parallel connection with the first switching element in a stepwise manner when the first switching element is turned off;
The first current reducing means includes
A circuit connected in parallel to the first switching element, the first series circuit including a first resistor and a second resistor, and a first circuit arranged in parallel to the second resistor Two switching elements, and the first resistor is connected in parallel to the first switching element by the ON operation of the second switching element,
The second current reducing means includes
A second series circuit including a third resistor and a third switching element; and the second series circuit is configured to turn on the third switching element when the first switching element is turned on. The first switching element and the first switching element are connected in parallel with each other, and after the first switching element is turned off, the third switching element is turned off. Is disconnected in parallel,
The third current reducing means includes
A circuit connected in parallel to the second series circuit during the ON operation of the first switching element, comprising a third series circuit including a fourth resistor and a fourth switching element; The third series circuit is connected in parallel to the first switching element together with the first resistor by the on operation of the fourth switching element when the first switching element is on. In the off operation of the switching element, the parallel connection with the first switching element is removed by the off operation of the fourth switching element after the third switching element is turned off. Current reducing device. The current reducing device according to claim 1,
The plurality of current reducing means includes:
First current reducing means connected in parallel to the first switching element;
A second current reducing means for removing the parallel connection with the first switching element from the state connected in parallel with the first switching element during the off operation of the first switching element; Prepared,
The first current reducing means includes
A first series circuit including a first resistor and a second switching element; and a second resistor connected in parallel with the first switching element, wherein the first series circuit is , By the on operation of the second switching element, connected in parallel to the first switching element,
The second current reducing means includes
A second series circuit including a third resistor and a third switching element; and the second series circuit is configured to turn on the third switching element when the first switching element is turned on. The parallel connection to the first switching element is disconnected in parallel with the first switching element, and when the first switching element is turned off, the parallel connection with the first switching element is removed by the off operation of the third switching element. A current reducing device. The current reducing device according to any one of claims 1 to 5,
The switching device is characterized in that a semiconductor material having a band gap larger than that of silicon or silicon is used as a base material. The current reducing device according to any one of claims 1 to 5,
The switching device is a MOSFET or IGBT voltage driven device. A first line is arranged in a path connecting a current breaker connected to the DC overhead line and a filter reactor connected to the power converter, and supplies power from the DC overhead line to the filter reactor by the ON operation. A switching element;
A bypass path is formed that is connected in parallel to the first switching element when the first switching element is turned on, and that guides current from the DC overhead line to the filter reactor when the first switching element is turned off. A current reducing method in a current reducing device comprising: a plurality of current reducing means for reducing current in the bypass path;
The current reducing method, wherein the plurality of current reducing means include a plurality of current reducing steps for gradually reducing an overcurrent generated in the DC overhead line due to a failure of the power converter or a ground fault. The current reducing method according to claim 8,
The plurality of current reduction steps include:
A main current reducing step in which main current reducing means among the plurality of current reducing means is connected in parallel to the first switching element;
One or more auxiliary current reducing means among the plurality of current reducing means are connected in parallel to the first switching element when the first switching element is turned off. One or more auxiliary current reducing steps in which the parallel connection with the switching element is removed. The current reducing method according to claim 8,
The plurality of current reducing means includes:
First current reducing means connected in parallel to the first switching element;
A second current reducing means for removing the parallel connection with the first switching element from the state connected in parallel with the first switching element during the off operation of the first switching element; Prepared,
The first current reducing means includes
A circuit connected in parallel to the first switching element, the first series circuit including a first resistor and a second resistor, and a first circuit arranged in parallel to the second resistor Two switching elements,
The second current reducing means includes
A second series circuit including a third resistor and a third switching element; and the second series circuit is configured to turn on the third switching element when the first switching element is turned on. Is connected in parallel to the first switching element together with the first resistor,
In the first current reducing step among the plurality of current reducing steps,
The first resistor is connected in parallel to the first switching element by the ON operation of the second switching element,
In the second current reducing step among the plurality of current reducing steps,
In the second series circuit, after the first switching element is turned off, the parallel connection with the first switching element is removed by the off operation of the third switching element. Current reduction method. The current reducing method according to claim 8,
The plurality of current reducing means includes:
First current reducing means connected in parallel to the first switching element;
A second current reducing means and a third current reducing means for removing the parallel connection with the first switching element in a stepwise manner when the first switching element is turned off;
The first current reducing means includes
A circuit connected in parallel to the first switching element, the first series circuit including a first resistor and a second resistor, and a first circuit arranged in parallel to the second resistor Two switching elements,
The second current reducing means includes
A second series circuit including a third resistor and a third switching element; and the second series circuit is configured to turn on the third switching element when the first switching element is turned on. Is connected in parallel to the first switching element together with the first resistor,
The third current reducing means includes
A circuit connected in parallel to the second series circuit during the ON operation of the first switching element, comprising a third series circuit including a fourth resistor and a fourth switching element; The third series circuit is connected in parallel to the first switching element together with the first resistor by the on operation of the fourth switching element when the first switching element is on.
In the first current reducing step among the plurality of current reducing steps,
The first resistor is connected in parallel to the first switching element by the ON operation of the second switching element,
In the second current reducing step among the plurality of current reducing steps,
After the first switching element is turned off, the second series circuit is disconnected from the parallel connection with the first switching element by the off operation of the third switching element.
In a third current reducing step among the plurality of current reducing steps,
When the third switching element is turned off when the first switching element is turned off, the fourth switching element is turned off after the third switching element is turned off. The current reduction method is characterized in that the parallel connection is removed. The current reducing method according to claim 8,
The plurality of current reducing means includes:
First current reducing means connected in parallel to the first switching element;
A second current reducing means for removing the parallel connection with the first switching element from the state connected in parallel with the first switching element during the off operation of the first switching element; Prepared,
The first current reducing means includes
A first series circuit including a first resistor and a second switching element; and a second resistor connected in parallel with the first switching element;
The second current reducing means includes
A second series circuit including a third resistor and a third switching element; and the second series circuit is configured to turn on the third switching element when the first switching element is turned on. Is connected in parallel to the first switching element,
In the first current reducing step among the plurality of current reducing steps,
The first series circuit is connected in parallel to the first switching element by the ON operation of the second switching element,
In the second current reducing step among the plurality of current reducing steps,
The second series circuit is configured such that when the first switching element is turned off, the parallel connection with the first switching element is disconnected by the off operation of the third switching element. Flow method.

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