WO2020161831A1

WO2020161831A1 - Power conversion device

Info

Publication number: WO2020161831A1
Application number: PCT/JP2019/004267
Authority: WO
Inventors: 佐々木　宏
Original assignee: 三菱電機株式会社
Priority date: 2019-02-06
Filing date: 2019-02-06
Publication date: 2020-08-13

Abstract

This power conversion device (5) comprises: a connector for connection to a storage battery (9); a converter (7) which bidirectionally converts a DC voltage of the storage battery (9) and a DC link voltage; an inverter (10) which bidirectionally converts the link voltage and an AC voltage of a system power supply (14); a control circuit (8) which controls the converter (7) and the inverter (10); and a control power supply (6) capable of supplying electric power to the control circuit (8) and the converter (7). The converter (7) includes a plurality of converter units (7a) that can be simultaneously driven in parallel. The control circuit (8) is characterized by stopping the operation of a part of the plurality of converter units (7a) and outputting a voltage to the connector, when performing an insulation test with the storage battery (9).

Description

Power converter

The present invention relates to a power conversion device used for charging and discharging a storage battery.

With the spread of electric vehicles in recent years, AC power from a system power supply is converted to DC power to charge a power supply device such as an electric vehicle equipped with a storage battery, and DC power discharged from the storage battery is converted to AC power. Power conversion devices for conversion have become widespread.

At the time of discharging the storage battery, first, the power conversion device uses the converter to convert the DC power of the storage battery into a DC link voltage and the inverter to convert the link voltage into an AC voltage. Here, the converter and the inverter are controlled by the control circuit. Normally, the power supplied from the system power supply is used as the power for driving the control circuit. In the event of a power failure of the system power supply, the power conversion device can drive the control circuit using the link voltage after generating the link voltage, but in order to generate the link voltage, the power conversion device drives the control circuit and the converter. Therefore, a power source other than the system power source is required.

Patent Document 1 discloses an electric vehicle equipped with an auxiliary power source in addition to a storage battery for driving. By using such an auxiliary power source, the control circuit can be driven even when the system power source fails.

Also, when the power converter is connected to the storage battery to perform charging/discharging, a procedure for an insulation test that outputs voltage to the connector connected to the storage battery to check if the insulation state is appropriate before starting charging/discharging. Is required. In case of a power failure of the system power supply, the power used for the insulation test must also be supplied from the auxiliary power supply.

JP, 2013-158218, A

However, the auxiliary power supply has an upper limit on the current that can be output. For example, a charging/discharging connector that complies with the V2H (Vehicle to Home) system standard, which is a system that supplies the electric power of a storage battery mounted on an electric vehicle to home electric appliances in a home, is set at 6.4A. Therefore, there is a problem that if the current consumed by the power conversion device in the insulation test is large, the supply upper limit of the current from the auxiliary power supply is exceeded.

The present invention has been made in view of the above, and an object thereof is to obtain a power conversion device capable of reducing power consumption in an insulation test.

In order to solve the above-mentioned problems and achieve the object, a power conversion device according to the present invention includes a connector that is connected to a storage battery, a converter that bidirectionally converts a DC voltage and a DC link voltage of the storage battery, and a link. A converter and a control circuit for controlling the inverter, and a control power supply capable of supplying power to the control circuit and the converter. The control circuit includes a plurality of drivable converter units, and when performing an insulation test with a storage battery, the control circuit stops a part of the plurality of converter units and outputs a voltage to the connector. To do.

The power converter according to the present invention has an effect of being able to reduce power consumption in an insulation test.

The figure which shows the structure of the power converter device concerning Embodiment 1 of this invention. The flowchart for demonstrating the operation|movement which the electric power converter shown in FIG. 1 starts an independent operation at the time of a power failure of a grid power supply. The figure which shows the structure of the power converter device concerning Embodiment 2 of this invention. The figure which shows the structure of the power converter device concerning Embodiment 3 of this invention. FIG. 3 is a diagram showing dedicated hardware for realizing the control circuit according to the first to third embodiments of the present invention. FIG. 3 is a diagram showing a hardware configuration of a control circuit according to the first to third embodiments of the present invention.

A power conversion device according to an embodiment of the present invention will be described in detail below with reference to the drawings. The present invention is not limited to the embodiments.

Embodiment 1.
FIG. 1 is a diagram showing the configuration of a power conversion device 5 according to the first embodiment of the present invention. The power conversion device 5 is connected to the electric vehicle 1, the system power supply 14, and the load 13. The electric vehicle 1 includes a storage battery 9 that is a power source for driving, an auxiliary battery 2, and a current limiter 3 that limits a current value supplied from the auxiliary battery 2. The power conversion device 5 uses the power from the system power supply 14 to charge the storage battery 9 of the electric vehicle 1 or supply the power stored in the storage battery 9 to the load 13. The electric power stored in the storage battery 9 and the electric power supplied to the load 13 have different types of electric power such as direct current and alternating current, and suitable voltage values. Therefore, the power conversion device 5 has a function of converting the type of electric power and the voltage value. Have.

The power conversion device 5 is a connector for electrically connecting to the storage battery 9 of the electric vehicle 1, and has a charging/discharging connector 4 having a connection line for connecting to the auxiliary battery 2, and a DC voltage and DC link of the storage battery 9. It has a converter 7 capable of bidirectionally converting a voltage and an inverter 10 capable of bidirectionally converting a link voltage and an AC voltage of the system power supply 14. The converter 7 has a plurality of converter units 7a that can be activated and operated independently of each other and can be simultaneously driven in parallel. The converter 7 can include a plurality of types of converter units 7a. For example, each of the plurality of converter units 7a is excellent in charge/discharge conversion efficiency at high power of about 3 kW, and low power conversion efficiency of about 0.1 kW used in the insulation test at startup. Things. The plurality of converter units 7a have different power consumptions.

The power conversion device 5 also includes a control circuit 8 that controls the converter 7 and the inverter 10, and a control power supply 6 that can supply power to the control circuit 8 and the converter 7. The control power supply 6 can supply power from the system power supply 14 or power from an auxiliary battery 2 that is an example of an auxiliary power supply different from the system power supply 14. When power is supplied from auxiliary battery 2, control power supply 6 is supplied with power via current limiter 3 and charge/discharge connector 4. For example, the control power supply 6 can start the control circuit 8 using the power from the auxiliary battery 2 when the power supply from the system power supply 14 is stopped.

The operation in which the power conversion device 5 converts the DC voltage stored in the storage battery 9 into a link voltage and supplies the link voltage is called an independent operation. In the state in which the power from the system power supply 14 is supplied, the control power supply 6 can start the converter 7 and the control circuit 8 by using the power from the system power supply 14 to start the self-sustained operation. Hereinafter, the operation of starting the self-sustaining operation when the power supply from the system power supply 14 is stopped, such as when the system power supply 14 fails, will be described.

FIG. 2 is a flow chart for explaining the operation of the power conversion device 5 shown in FIG. 1 to start the self-sustaining operation when the system power supply 14 fails. First, the auxiliary battery 2 generates a DC voltage, and the electric power from the auxiliary battery 2 to the control power supply 6 of the power conversion device 5 is passed through the current limiter 3 and the connection line built in the charge/discharge connector 4. Supply is started (step S101). The control power supply 6 starts supplying power from the control power supply 6 to the converter 7 and the control circuit 8 (step S102). When power is supplied, the control circuit 8 starts operating.

The control circuit 8 stops the operation of some converter units 7a of the plurality of converter units 7a (step S103). For example, the control circuit 8 may operate some converter units 7a by stopping the operation of some converter units 7a after starting all converter units 7a, or may operate some converter units 7a from the beginning. It is also possible to activate only the converter unit 7a and keep the operation of the other converter units 7a stopped. The control circuit 8 can select the converter unit 7a to operate based on the power consumption of each of the plurality of converter units 7a. The control circuit 8 can supply a necessary electric power among the plurality of converter units 7a and can operate a part of the converter units 7a that operate at the minimum current value. For example, the control circuit 8 operates one converter unit 7a having the lowest power consumption among the plurality of converter units 7a.

The control circuit 8 controls the converter unit 7a to convert the voltage value of the electric power supplied from the control power supply 6 to the converter unit 7a, and to apply the voltage to the charge/discharge connector 4, thereby performing the insulation test. (Step S104). As the electric power used for the insulation test, any voltage value and current value can be used as long as it can be confirmed that the electric vehicle 1 and the power conversion device 5 are electrically connected and there is no short circuit. For example, the power used for the insulation test is about 450 V and 30 mA.

The control circuit 8 determines whether or not there is a short circuit as a result of the insulation test (step S105). When there is no short circuit (step S105: No), the control circuit 8 operates all the converter units 7a to start power conversion (step S106). When there is a short circuit (step S105: Yes), the control circuit 8 omits the process of step S106 and ends the process.

In response to the instruction from the control circuit 8, the converter 7 converts the DC voltage supplied from the storage battery 9 mounted on the electric vehicle 1 via the charge/discharge connector 4 into a DC link voltage. Here, the voltage supplied from the storage battery 9 is an indefinite value that varies depending on the type of the electric vehicle 1, the charge rate, and the like, and the value of the link voltage is constant.

When the operation shown in FIG. 2 ends and the converter 7 converts the DC voltage supplied from the storage battery 9 into a link voltage, the DC voltage is converted into an AC voltage by the inverter 10 controlled by the control circuit 8, and the load 13 is supplied with electric power. Is supplied.

As described above, in the power conversion device 5 according to the first embodiment of the present invention, the converter 7 includes the plurality of converter units 7a, and the control circuit 8 performs the insulation test performed before the start of charging/discharging. At times, some of the plurality of converter units 7a are operated. With such a configuration, power consumption in the insulation test can be reduced as compared with the case where all converter units 7a are operated. Therefore, there is an effect that the current limitation imposed on the auxiliary battery connection path from the auxiliary battery 2 via the charge/discharge connector 4 to the control power supply 6 is less likely to occur.

Embodiment 2.
FIG. 3 is a diagram showing the configuration of the power conversion device 5a according to the second embodiment of the present invention. Hereinafter, parts different from the first embodiment will be mainly described. The power converter 5a has an accessory socket 11 in addition to the configuration of the power converter 5 according to the first embodiment. The accessory socket 11 has a connection line connected to the auxiliary battery 2. In the power conversion device 5, the connection line from the control power supply 6 is connected to the auxiliary battery 2 via the charge/discharge connector 4 and the current limiter 3, whereas in the power conversion device 5a, the control power supply 6 charges the power. The connection line is connected to the auxiliary battery 2 via the accessory socket 11 and the current limiter 3 without passing through the discharge connector 4. The current that can be used in the accessory socket 11 is limited by a fuse or the like provided in the accessory socket 11. The operation of the power conversion device 5a when the power supply from the system power supply 14 is stopped is the same as the operation of the first embodiment shown in FIG. 2, and therefore detailed description thereof is omitted here.

As described above, the power conversion device 5a according to the second embodiment of the present invention is charged in the state in which some of the plurality of converter units 7a are stopped during the insulation test, as in the first embodiment. A voltage is applied to the discharge connector 4. With such a configuration, the power consumption in the insulation test can be reduced, and the insulation test can be performed even when the voltage of the auxiliary battery 2 is reduced because the voltage drop in the transmission path is small. Play.

Embodiment 3.
FIG. 4 is a diagram showing the configuration of the power conversion device 5b according to the third embodiment of the present invention. Hereinafter, parts different from the first embodiment will be mainly described. The power conversion device 5b further includes a connection line that can be connected to the external power supply 12, which is an example of an auxiliary power supply, without using the charge/discharge connector 4. When the power supply from the system power supply 14 is stopped, power is supplied from the external power supply 12 to the control power supply 6. The operation of power conversion device 5b when the power supply from system power supply 14 is stopped is the same as that of the first embodiment except that external power supply 12 is used instead of auxiliary battery 2 in step S101 shown in FIG. Therefore, detailed description is omitted here.

As described above, the power conversion device 5b according to the third embodiment of the present invention is charged in the state where some of the plurality of converter units 7a are stopped during the insulation test, as in the first embodiment. A voltage is applied to the discharge connector 4. With such a configuration, it is possible to reduce the power consumption in the insulation test and to perform the insulation test even when the output of the external power supply 12 is limited.

Next, the hardware configuration of the control circuit 8 according to the first to third embodiments of the present invention will be described. The control circuit 8 may be realized by dedicated hardware or a circuit using a CPU (Central Processing Unit).

When the above processing circuits are realized by dedicated hardware, these are realized by the processing circuit 90 shown in FIG. FIG. 5 is a diagram showing dedicated hardware for realizing the control circuit 8 according to the first to third embodiments of the present invention. The processing circuit 90 is a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination thereof.

When the above processing circuit is realized by a circuit using a CPU, this circuit has a configuration shown in FIG. 6, for example. FIG. 6 is a diagram showing a hardware configuration of the control circuit 8 according to the first to third embodiments of the present invention. As shown in FIG. 6, the control circuit 8 can be realized by using a processor 92 and a memory 93. The processor 92 is a CPU and is also called a central processing unit, a processing unit, an arithmetic unit, a microprocessor, a microcomputer, a DSP (Digital Signal Processor), or the like. The memory 93 is, for example, a nonvolatile or volatile semiconductor memory such as a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (Erasable Programmable ROM), and an EEPROM (registered trademark) (Electrically EPROM), These include magnetic disks, flexible disks, optical disks, compact disks, mini disks, and DVD (Digital Versatile Disk).

The processor 92 can realize various functions of the control circuit 8 by reading and executing a program stored in the memory 93 and corresponding to the processing of each component. The memory 93 is also used as a temporary memory in each process executed by the processor 92.

The configurations described in the above embodiments are examples of the content of the present invention, and can be combined with other known techniques, and the configurations of the configurations are not departing from the scope of the present invention. It is also possible to omit or change parts.

1 electric vehicle, 2 auxiliary battery, 3 current limiter, 4 charge/discharge connector, 5, 5a, 5b power converter, 6 control power supply, 7 converter, 7a converter unit, 8 control circuit, 9 storage battery, 10 inverter, 11 Accessory socket, 12 external power supply, 13 load, 14 system power supply, 90 processing circuit, 92 processor, 93 memory.

Claims

A connector that connects to the storage battery,
A converter that bidirectionally converts the DC voltage of the storage battery and the DC link voltage,
An inverter that bidirectionally converts the link voltage and the AC voltage of the system power supply,
A control circuit for controlling the converter and the inverter;
A control power supply capable of supplying power to the control circuit and the converter,
Have
The converter includes a plurality of converter units that can be simultaneously driven in parallel,
The power conversion device, wherein the control circuit stops operation of a part of the plurality of converter units and outputs a voltage to the connector when performing an insulation test with the storage battery.
The power converter according to claim 1, wherein the control circuit selects a converter unit to stop the operation based on the power consumption of each of the plurality of converter units when performing the insulation test.
The control circuit operates one converter unit having the lowest power consumption among the plurality of converter units and stops the operation of the other converter units when performing the insulation test. The power converter described.
4. The control power supply activates the control circuit by using the power of an auxiliary power supply different from the system power supply when the power supply from the system power supply is stopped. The power converter described.
The storage battery is mounted on an electric vehicle,
The auxiliary power source is an auxiliary battery mounted on the electric vehicle,
The power conversion device according to claim 4, wherein the connector has a connection line that is connected to the auxiliary battery.
The storage battery is mounted on an electric vehicle,
The auxiliary power source is an auxiliary battery mounted on the electric vehicle,
The power conversion device according to claim 4, further comprising an accessory socket having a connection line connected to the auxiliary battery.
The power converter according to claim 4, further comprising a connection line that connects the power of the auxiliary power supply to the control circuit.