JP7615399B2 - Electric vehicle control device - Google Patents

Description

The present disclosure relates to an electric vehicle control device that receives power from an external power source and discharges the power to the outside.

Electric vehicles use an inverter to convert DC power to AC power and supply it to an auxiliary power supply unit. Before the inverter is operated, it is necessary to charge the filter capacitor, and after the inverter stops operating, the charge accumulated in the filter capacitor must be discharged. Patent Document 1 discloses that the vehicle is provided with a discharge circuit for discharging the filter capacitor.

JP 2010-41806 A

Patent document 1 discloses that when the inverter is stopped, a discharge current from the filter capacitor through the initial charging circuit is detected, and when the discharge current detected by the current detection sensor during the stop operation exceeds a predetermined value, a fault detection unit determines that a short-circuit fault has occurred in the reverse current prevention element of the initial charging circuit. However, patent document 1 has a problem in that if there is an abnormality in the discharge circuit due to poor contact of the components that make up the discharge circuit, the charge in the filter capacitor cannot be discharged.

The present disclosure has been made to solve the problems described above, and aims to provide an electric vehicle control device that can reliably discharge the charge in the filter capacitor when an abnormality occurs in the discharge circuit.

In order to achieve the above object, an electric vehicle control device according to the present disclosure includes a power conversion device mounted on an electric vehicle, receiving power from a power source and converting DC power into AC power, a first switch for switching between passing and cutting off a current flowing between the power source and the power conversion device, a capacitor connected to the DC side of the power conversion device, a first discharge circuit connected to both ends of the capacitor and comprising a discharge resistor and a discharge contactor, and a second discharge circuit connected to both ends of the capacitor and comprising a second switch and a first resistor that is a charging resistor and a discharging resistor connected in series between the first switch and the capacitor , and discharging the capacitor by the first resistor connected to the capacitor via the second switch that is closed . After an abnormality in the first discharge circuit is detected, the first switch is opened, and the second switch is closed in conjunction with the opening of the first switch.

The electric vehicle control device disclosed herein is equipped with a power conversion device that is mounted on an electric vehicle and receives power from a power source and converts DC power into AC power, a first switch that switches between passing and cutting off the current flowing between the power source and the power conversion device, a capacitor connected to the DC side of the power conversion device, a first discharge circuit that is connected to both ends of the capacitor and is composed of a discharge resistor and a discharge contactor, and a second discharge circuit that is connected to both ends of the capacitor and is composed of a second switch and a first resistor connected in series between the first switch and the capacitor, thereby enabling the charge in the filter capacitor to be reliably discharged.

1 is a block diagram showing a configuration example of an electric vehicle control device according to a first embodiment; FIG. 2 is a diagram illustrating an example of the operation of the electric vehicle control device according to the first embodiment. FIG. 11 is a block diagram showing a configuration example of an electric vehicle control device according to a second embodiment. FIG. 1 is a diagram illustrating an example of a general configuration of hardware for implementing an electric vehicle control device according to an embodiment.

Hereinafter, an embodiment of an electric vehicle control device according to the present disclosure will be described with reference to the drawings.
In this specification and the drawings, components having substantially the same functions are denoted by the same reference numerals, and redundant explanations are omitted. Also, in the drawings, diagrams showing circuit and device configurations are merely diagrams showing schematic configurations. In the following description, "connected" means "electrically connected."

Embodiment 1.
Fig. 1 is a block diagram showing a configuration example of an electric vehicle control device according to a first embodiment of the present disclosure. In Fig. 1, the electric vehicle control device includes a power conversion device 10, a filter capacitor 20, a voltage detector 21, a first switch 30, a second switch 31, a circuit breaker 40, a filter reactor 50, a backflow prevention thyristor 60, a first resistor 70, discharge resistors 80 and 81, and a discharge contactor 90.

The power conversion device 10 converts the power supplied from the power source 12 into DC power or AC power, and supplies the converted power to a load (not shown). Here, the load is, for example, an auxiliary power supply device. The power conversion device 10 is, for example, a two-level three-phase inverter circuit or a three-level three-phase inverter circuit.

The current collector 11 obtains DC power from a substation (not shown), which is an external circuit, via a power source 12, and supplies the power to the power conversion device 100. The current collector 11 is, for example, a pantograph that receives power from an overhead line, or a collector shoe that receives power from a third rail.

The power source 12 is connected to a substation and receives DC power from the substation. The power source 12 is, for example, an overhead line or a third rail.

The filter capacitor 20 is provided in parallel with the power conversion device 10. One end of the filter capacitor 20 is connected to the power conversion device 10, the voltage detector 21, the backflow prevention thyristor 60, the first resistor 70, and the discharge resistors 80 and 81. The other end of the filter capacitor 20 is grounded. The filter capacitor 20 is provided on the DC side of the power conversion device 10.

The voltage detector 21 is provided in parallel with the power conversion device 10. One end of the voltage detector 21 is connected to the power conversion device 10, the filter capacitor 20, the backflow prevention thyristor 60, the first resistor 70, and the discharge resistors 80 and 81. The other end of the voltage detector 21 is grounded.

The first switch 30 is electrically connected in series between the current collector 11 and the power conversion device 10. One end of the first switch 30 is connected to the current collector 11. The other end of the first switch 30 is connected to the circuit breaker 40. The first switch 30 is opened when it is necessary to stop the supply of power to the electric vehicle. When the first switch 30 is opened, the current collector 11 and the power conversion device 10 are electrically disconnected, and the supply of power from the current collector 11 to the power conversion device 10 is stopped. When it is necessary to supply power to the electric vehicle, the first switch 30 is closed. When the first switch 30 is closed, the current collector 11 and the power conversion device 100 are electrically connected, and power is supplied from the power source 12 to the power conversion device 10.

The circuit breaker 40 is electrically connected in series between the current collector 11 and the power conversion device 10. One end of the circuit breaker 40 is connected to the first switch 30. The other end of the circuit breaker 40 is connected to the filter reactor 50. The circuit breaker 40 is opened when it is necessary to stop the supply of power to the electric vehicle. When the circuit breaker 40 is opened, the current collector 11 and the power conversion device 10 are electrically disconnected, and the supply of power from the current collector 11 to the power conversion device 10 is stopped. When it is necessary to supply power to the electric vehicle, the circuit breaker 40 is closed. When the circuit breaker 40 is closed, the current collector 11 and the power conversion device 10 are electrically connected, and power is supplied from the power source 12 to the power conversion device 100.

The filter reactor 50 is electrically connected in series between the current collector 11 and the power conversion device 10. One end of the filter reactor 50 is connected to the circuit breaker 40. The other end of the filter reactor 50 is connected to the second switch 31, the backflow prevention thyristor 60, and the first resistor 70. The filter reactor 50 smoothes the current flowing from the power source 12 to the power conversion device 10. The filter reactor 50 and the filter capacitor 20 form an LC filter circuit and are provided to suppress harmonics generated when the power conversion device 10 performs power conversion from flowing to the power source 12.

The backflow prevention thyristor 60 is electrically connected in series between the current collector 11 and the power converter 10. One end of the backflow prevention thyristor 60 is connected to the second switch 31, the filter reactor 50, and the first resistor 70. The other end of the backflow prevention thyristor 60 is connected to the power converter 10, the filter capacitor 20, the voltage detector 21, the first resistor 70, and the discharge resistors 80 and 81. The backflow prevention thyristor 60 is connected in parallel with the first resistor 70. The backflow prevention thyristor 60 prevents current from flowing from the filter capacitor 20 to the power source 12.

The first resistor 70 is electrically connected in series between the current collector 11 and the power converter 10. One end of the first resistor 70 is connected to the second switch 31, the filter reactor 50, and the backflow prevention thyristor 60. The other end of the first resistor 70 is connected to the power converter 10, the filter capacitor 20, the voltage detector 21, the backflow prevention thyristor 60, and the discharge resistors 80 and 81. The first resistor 70 is connected in parallel with the backflow prevention thyristor 60. The first resistor 70 is a charging resistor for preventing inrush current when charging the filter capacitor 20. The first resistor 70 also serves as a discharge resistor in the event of a discharge abnormality in the filter capacitor 20. Details will be described later. The first resistor 70 is connected in series between the first switch 30 and the filter capacitor 20.

The discharge resistors 80 and 81 are provided in parallel with the power conversion device 10. The discharge resistors 80 and 81 are connected in parallel. One end of the discharge resistors 80 and 81 is connected to the power conversion device 10, the filter capacitor 20, the voltage detector 21, the backflow prevention thyristor 60, and the first resistor 70. The other end of the discharge resistors 80 and 81 is connected to the discharge contactor 90. Since the electric vehicle control device has multiple discharge resistors, even if one of the discharge resistors has an abnormality due to poor contact, discharging is possible by passing electricity through the other discharge resistor that has no poor contact. Three or more discharge resistors may be provided.

The discharge contactor 90 is provided in parallel with the power conversion device 10. One end of the discharge contactor 90 is connected to the discharge resistors 80 and 81. The other end of the discharge contactor 90 is grounded. The discharge resistors 80 and 81 are connected in series with the discharge contactor 90. The discharge resistors 80, 81 and the discharge contactor 90 are connected across the capacitor to form a first discharge circuit.

The second switch 31 is provided in parallel with the power conversion device 10. One end of the second switch 31 is connected to the filter reactor 50, the backflow prevention thyristor 60, and the first resistor 70. The other end of the second switch 31 is grounded. The second switch 31 is connected in series with the first resistor 70. The second switch 31 and the first resistor 70 constitute a second discharge circuit. The second switch 31 is normally open and does not conduct electricity. The second switch 31 is closed when a discharge abnormality occurs in the filter capacitor 20. By closing the second switch 31, the charge stored in the filter capacitor 20 is discharged. Details will be described later.

The operation of the electric vehicle control device according to the first embodiment of the present disclosure will be described. The charging operation of charging the filter capacitor 20 will be described. In order to operate the power conversion device 10, the filter capacitor 20 is charged. In order to charge the filter capacitor 20, it is necessary to supply power from the power source 12, and the first switch 30 and the circuit breaker 40 are turned on (closed). By turning off the backflow prevention thyristor 60, not conducting the backflow prevention thyristor 60, and conducting the first resistor 70, it is possible to charge the filter capacitor 20 without an inrush current flowing. After detecting a voltage equal to or greater than a predetermined value in the voltage detector 21, the backflow prevention thyristor 60 is turned on and the backflow prevention thyristor 60 is conducted, thereby short-circuiting and charging the filter capacitor 20. The first switch 30 and the circuit breaker 40 are turned on during the period in which the filter capacitor 20 is being charged.

Next, a diagram for explaining the operation of discharging the filter capacitor 20 of the electric vehicle control device according to the first embodiment will be described. The control unit (not shown) of the electric vehicle control device opens the circuit breaker 40 to start discharging the filter capacitor 20 (S11). When the circuit breaker 40 is opened, the supply of power from the power source 12 is stopped. Next, the operation of the power conversion device 10 is stopped (S12). The discharge contactor 90 is turned on (S13), and the charge accumulated in the filter capacitor is discharged. After a predetermined period of time has elapsed, it is confirmed whether the voltage value of the voltage detector 21 is equal to or lower than a predetermined value (predetermined value) (S14). If the voltage value of the voltage detector 21 is equal to or lower than the predetermined value after the predetermined period of time has elapsed (S14: Y), there is no abnormality in the first discharge circuit, so the discharge is performed normally, and it is confirmed that the voltage value of the voltage detector 21 is 0 V (S16), and the discharge operation is completed. If the voltage value of the voltage detector 21 is not equal to or lower than the predetermined value after a predetermined period of time has elapsed after the discharge contactor 90 is turned on (S14: N), it is determined that there is an abnormality in the first discharge circuit because the discharge is not being performed. In other words, an abnormality in the first discharge circuit is detected. Therefore, in order to ensure discharge, the first switch 30 is opened and the second switch 31 is turned on (S15). By turning on the second switch 31, a second discharge circuit is formed by the first resistor 70 and the second switch 31. The second discharge circuit discharges the filter capacitor 20, and when it is confirmed that the voltage value of the voltage detector 21 is 0 V (S16), the discharge operation is completed.

The electric vehicle control device according to the first embodiment has a plurality of discharge resistors in the first discharge circuit, so that even if one discharge resistor does not conduct electricity due to poor contact, discharging is possible by conducting the other discharge resistor that has no poor contact. Furthermore, even if there is no abnormality in the discharge resistor, normal discharge is not possible if there is an abnormality in the discharge contactor 90. Even in this case, the electric vehicle control device detects an abnormality in the first discharge circuit by monitoring the voltage value of the voltage detector 21, and forms a second discharge circuit. Discharging by the second discharge circuit ensures that the charge in the filter capacitor 20 is discharged.

It has been stated that the voltage detector 21 checks whether the voltage value is equal to or lower than a predetermined value after a predetermined period of time has elapsed. Here, the predetermined period is, for example, 5 minutes, and the predetermined value is, for example, 50 V, but is not limited to these. The predetermined period and the predetermined value may be set as appropriate.

The electric vehicle control device according to the first embodiment operates the first switch 30 and the second switch 31 in conjunction with each other when forming the second discharge circuit. By linking the first switch 30 and the second switch 31, the first switch 30 is opened so that no current flows to the power source 12 side, and the second switch 31 is closed so that the current can be reliably passed to the ground side. In addition, the second discharge circuit energizes the first resistor 70, which causes a voltage drop and prevents low impedance during discharge. Low impedance refers to a case where the high voltage side and low voltage side of the filter capacitor 20 are short-circuited. If low impedance occurs during discharge, a large current flows, and there is a risk of electric shock. However, the electric vehicle control device according to the first embodiment can prevent low impedance during discharge.

In the electric vehicle control device according to the first embodiment, the backflow prevention thyristor 60 may be connected in series with a contactor (not shown). In this case, the contactor may be turned on when the filter capacitor 20 is charged and turned off when the filter capacitor 20 is discharged. By connecting the contactor in series with the backflow prevention thyristor 60, a second discharge circuit is formed. When the filter capacitor 20 is discharged, the contactor is turned off. Therefore, the discharge current does not flow through the backflow prevention thyristor 60 but flows through the first resistor 70. Therefore, even if the backflow prevention thyristor 60 is shorted, the first resistor 70 is reliably energized, and low impedance during discharge can be prevented.

The electric vehicle control device of the first embodiment is equipped with a power conversion device mounted on an electric vehicle, which receives power from a power source and converts DC power into AC power, a first switch which switches between passing and cutting off the current flowing between the power source and the power conversion device, a capacitor connected to the DC side of the power conversion device, a first discharge circuit connected to both ends of the capacitor and consisting of a discharge resistor and a discharge contactor, and a second discharge circuit connected to both ends of the capacitor and consisting of a second switch and a first resistor connected in series between the first switch and the capacitor, thereby enabling the charge of the filter capacitor to be reliably discharged.

The electric vehicle control device in embodiment 1 is equipped with a voltage detector connected in parallel with the capacitor, and by monitoring the voltage of the voltage detector, an abnormality in the first discharge circuit is detected, and it is detected that the charge of the filter capacitor cannot be discharged by the first discharge circuit.

In the electric vehicle control device of embodiment 1, after an abnormality in the first discharge circuit is detected, the opening of the first switch and the closing of the second switch are controlled in conjunction with each other, making it possible to change the discharge path to the second discharge circuit.

In the electric vehicle control device of embodiment 1, the discharge resistor is configured so that multiple resistors are connected in parallel, so that the charge in the filter capacitor can be reliably discharged even if one of the resistors is defective.

Embodiment 2.
In the first embodiment, the second discharge circuit is formed by the first resistor 70 and the second switch 31. In the second embodiment, the second discharge circuit includes the filter reactor 50.

Figure 3 is a block diagram showing an example configuration of an electric vehicle control device according to embodiment 2 of the present disclosure. In Figure 3, the difference from embodiment 1 is that a contactor 100 is provided.

One end of the contactor 100 is connected to the circuit breaker 40 and the filter reactor 50. The other end of the contactor 100 is connected to the second switch 31. The contactor 100 is opened when the filter capacitor 20 is charged. Therefore, the control for charging the filter capacitor 20 is the same as in the first embodiment.

The contactor 100 is turned on when the filter capacitor 20 is discharged. When the filter capacitor 20 is discharged, in S15 of FIG. 2, the second switch 31 is turned on and the contactor 100 is turned on. When the contactor 100 is turned on, the second discharge circuit is composed of the first resistor 70, the filter reactor 50, the contactor 100 and the second switch 31. By providing the filter reactor 50 in the second discharge circuit, when the charge of the filter capacitor 20 is discharged, the amount of current at the start of discharge can be suppressed by the time constant of the filter reactor 50, making it possible to suppress the inrush current.

The electric vehicle control device of embodiment 2 is provided with a filter reactor connected in series between the second switch and the first resistor, thereby making it possible to suppress the amount of current at the start of discharging when discharging the charge of the filter capacitor.

The control unit (not shown) of the electric vehicle control device includes at least a processor, a memory, a receiver, and a transmitter, and the operation of each device can be realized by software. FIG. 4 is a diagram showing a general configuration example of hardware that realizes the control unit of the electric vehicle control device according to the embodiment. The device shown in FIG. 4 includes a processor 1001, a memory 1002, a receiver 1003, and a transmitter 1004, and the processor 1001 performs calculations and control by software using received data. The memory 1002 stores the received data or data required for the processor 1001 to perform calculations and control, and also stores software. The receiver 1003 is an interface that receives signals or information input to the electric vehicle control device. The transmitter 1004 is an interface that transmits signals or information output from the electric vehicle control device. Note that the processor 1001, the memory 1002, the receiver 1003, and the transmitter 1004 may each be provided in multiple units.

In the first and second embodiments, when the charge of the filter capacitor 20 is discharged, the first discharge circuit and the second discharge circuit are switched and one of the discharge circuits is used for discharging. However, both discharge circuits may be used simultaneously. When both discharge circuits are used, even if one of the discharge circuits cannot discharge due to poor contact or the like, it is possible to continue discharging using the other discharge circuit without switching. Furthermore, if there is a discharge circuit that cannot discharge, the contactor or the second switch is opened so as not to pass current through the discharge circuit that cannot discharge. Specifically, if the first discharge circuit cannot discharge, the discharge contactor 90 is opened, and if the second discharge circuit cannot discharge, the second switch 31 is opened.

In the first and second embodiments, the means for detecting that the first discharge circuit is abnormal may be automatic or manual. The voltage value of the voltage detector 21 may be output to an external device, and the external device may check whether the voltage value of the voltage detector 21 is equal to or lower than a predetermined value after a predetermined period of time has elapsed.

In embodiments 1 and 2, the control of closing and opening the discharge contactor 90 of the first discharge circuit and the second switch 31 of the second discharge circuit may be performed automatically or manually.

10 Power conversion device, 11 Current collector, 12 Power source, 20 Filter capacitor, 21 Voltage detector, 30 First switch, 31 Second switch, 40 Circuit breaker, 50 Filter reactor, 60 Backflow prevention thyristor, 70 First resistor, 80, 81 Discharge resistor, 90 Discharge contactor, 100 Contactor, 1001 Processor, 1002 Memory, 1003 Receiver, 1004 Transmitter 10.

Claims (4)

a power conversion device that is mounted on the electric vehicle and receives power from a power source and converts DC power into AC power;
a first switch that switches between passing and cutting off a current flowing between the power source and the power conversion device;
A capacitor connected to a DC side of the power conversion device;
a first discharge circuit connected across the capacitor and including a discharge resistor and a discharge contactor;
a second discharge circuit that is connected to both ends of the capacitor, and that is composed of a first resistor that is a charging resistor and a discharging resistor that are connected in series between the first switch and the capacitor, and a second switch, and that discharges the capacitor by the first resistor that is connected to the capacitor via the second switch that is turned on ;
Equipped with
After an abnormality in the first discharge circuit is detected, the first switch is opened, and the second switch is turned on in conjunction with the opening of the first switch.
Electric vehicle control device. a voltage detector connected in parallel with the capacitor;
The voltage of the voltage detector is monitored to detect an abnormality in the first discharge circuit.
The electric vehicle control device according to claim 1 . The discharge resistor is a plurality of resistors connected in parallel.
3. An electric vehicle control device according to claim 1 or 2 . the second discharge circuit includes a filter reactor connected in series between the second switch and the first resistor.
The electric vehicle control device according to any one of claims 1 to 3 .

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