ELECTRIC VEHICLE INVERTER APPARATUS AND PROTECTION METHOD THEREFOR

• US 20100214055A1
• Filed: 02/19/2010
• Published: 08/26/2010
• Est. Priority Date: 02/20/2009
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Yaskawa Denki, Mazda Motor Corporation
• Original Assignee: Kabushiki Kaisha Yaskawa Denki, Mazda Motor Corporation
• Inventors: TANAKA, Yoshinori, FURUKAWA, Akihiro, YAMADA, Kenji, YONEMORI, Kei, SEO, Nobuhide, EBISUMOTO, Hirofumi, AMANO, Ryuichiro, FUJI, Kiyotaka, HARA, Hidenori
• Granted Patent: US 8,612,073 B2
• Time in Patent Office: Days
• US Class Current: 340/3.100
• CPC Class Codes: B60L 3/00 Electric devices on electrically-propelled vehicles for safety purposes; Monitoring operating variables, e.g. speed, deceleration or energy consumption methods or circuit arrangements for monitoring or controlling batteries or fuel cells B60L58/00
• CPC Class Codes: B60L 3/04 Cutting off the power supply under fault conditions protective devices and circuit arrangements in general H01H; H02H
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: H02H 9/001 limiting speed of change of electric quantities, e.g. soft switching on or off progressive control of electronic switches for eliminating interferences H03K17/16
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

In an electric vehicle inverter apparatus 100, a vehicle control controller 15 detects a switch open signal output from a collision detector 16 when the collision detector 16 is caused by a collision between electric vehicles to operate. Then, an inverter main circuit connection switch 10 of a high-voltage battery unit 8 is put into an open state. Thus, the direct-current power supply from a high-voltage battery 12 to a DC bus portion is interrupted. In addition, electric charges charged into a main circuit capacitor 7 are discharged by a forced discharge circuit portion 22b.

Claims

1. An electric vehicle inverter apparatus comprising:

an inverter portion configured to drive an AC electric motor mechanically connected to a vehicle drive portion of an electric vehicle;

a converter portion configured to convert electric power generated by the AC electric generator which generates electric power by an engine driving force of the electric vehicle into a direct-current voltage within predetermined range of voltages;

an inverter controller configured to control the inverter portion and the converter portion;

a main circuit capacitor connected between DC bus of the inverter and the converter; and

a forced discharge circuit portion configured to discharge electric charges charged into the main circuit capacitor in response to a discharge command signal,

direct-current electric power for the inverter portion being supplied from a high-voltage battery unit which includes an inverter main circuit connection switch, a high-voltage battery and an inrush current suppression circuit configured to suppress an inrush current from the high-voltage battery when the inverter main circuit connection switch is thrown and which is connected to the DC bus,

control power being supplied from a low-voltage battery unit which includes a low-voltage battery and a switch configured to open and close the low-voltage battery,

the electric vehicle inverter apparatus receiving and being controlled according to both of a control signal from a vehicle control controller configured to supervisingly control the electric vehicle and a control signal from a collision detector which is connected between the vehicle control controller and the low-voltage battery and which includes a switch configured to be put into an open state when detecting impact due to a collision of the electric vehicle, wherein

the vehicle control controller detects an open signal indicating that a switch of the collision detector is opened when the collision detector is operated by the collision of the electric vehicle;

the vehicle control controller brings the inverter main circuit connection switch of the high-voltage battery unit into an open state, interrupts supply of direct-current electric power of the high-voltage battery to the DC bus portions and outputs a discharge command signal to the forced discharge circuit portion; and

the forced discharge circuit portion discharges electric charges charged into the main circuit capacitor.

2. The electric vehicle inverter apparatus as in claim 1, wherein

the forced discharge circuit portion comprises:

a discharge circuit portion including a discharge resistor, a power semiconductor element, and a discharge current detection resistor, which are series-connected between the DC bus;

a discharge resistor overheat protection circuit portion configured to operate by receiving a voltage generated by voltage drop due to discharge current flowing through the discharge current detection resistor as an input thereto;

a gate power supply circuit portion configured to generate drive power for the power semiconductor element from a direct-current voltage between the DC bus;

a drive circuit portion configured to give a drive signal to a control terminal of the power semiconductor element; and

a discharge signal latch circuit portion configured to receive a discharge command signal according to a detection signal from the collision detector and to give a drive signal to the drive circuit portion;

when receiving a discharge command signal according to a detection signal from the collision detector, the discharge signal latch circuit portion maintains an on-signal to the drive circuit portion so that the discharge circuit portion can constantly maintain a discharge operation on-state; and

when a terminal voltage of the main circuit capacitor is lowered to a value close to 0 volt by a discharge operation, and when a power supply voltage of the gate power supply circuit portion is lowered to a value which is equal to or lower than an operable voltage of the drive circuit portion, the discharge operation on-state is cancelled.

3. The electric vehicle inverter apparatus as in claim 1, wherein

the forced discharge circuit portion comprises:

a DC-DC converter configured to convert a battery voltage supplied from the low-voltage battery into an operating voltage of a control circuit portion;

a storage portion configured to store an output voltage of the DC-DC converter;

a discharge operation command input portion configured to input a detection signal from the collision detector and a discharge signal from the vehicle control controller;

a discharge command delay portion configured to prevent occurrence of chattering of the signal input to the discharge operation command input portion;

a discharge signal insulation portion configured to electrically insulate an output signal from the discharge command delay portion; and

the storage portion has storage capacity sufficient to an extent that a voltage drop due to interruption of a voltage supplied from the low-voltage battery unit can slightly be delayed on collision of the electric vehicle, and can maintain a power supply voltage at which a control circuit portion is operable until a discharge operation of the forced discharge circuit portion is started up.

4. The electric vehicle inverter apparatus as in claim 2, wherein

the gate power supply circuit portion comprises a resistor and a zener diode series-connected via a diode between the DC bus, and electrolytic capacitors series-connected to each other and parallel-connected to the resistor and the zener diode, respectively;

and

a zener voltage of the zener diode is higher than an operable voltage of the drive circuit portion, and equal to and lower than an allowable gate voltage of the power semiconductor element.

5. The electric vehicle inverter apparatus as in claim 2, wherein

a power semiconductor element of the discharge circuit portion includes a MOSFET or an IGBT.

6. The electric vehicle inverter apparatus as in claim 2, wherein

the drive circuit portion comprises:

a first gate resistor connected to a gate of the power semiconductor element including a MOSFET or an IGBT;

a first PNP transistor and a second gate resistor series-connected to the first gate resistor; and

a third resistor and a zener diode series-connected to a base of the first PNP transistor;

the discharge signal latch circuit portion is provided at the side of an anode of the zener diode; and

the discharge signal latch circuit portion comprises an NPN transistor and a PNP transistor, which are connected together as a thyristor.

7. The electric vehicle inverter apparatus as in claim 2, wherein

the discharge resistor overheat protection circuit portion introduces a terminal voltage of the discharge current detection resistor of the discharge circuit portion to a base of an NPN transistor via a resistor;

a capacitor and a resistor are parallel-connected to each other between a base-emitter junction of the NPN transistor;

a base of a PNP transistor is connected to a collector of the NPN transistor;

a collector of the PNP transistor is connected to a base of the NPN transistor; and

an emitter of the PNP transistor is connected to a connection point between the second gate resistor of the drive circuit portion and an emitter of the first PNP transistor.

8. The electric vehicle inverter apparatus as in claim 3, wherein

the forced discharge circuit portion is configured so that a discharge command latch portion is provided between the discharge command delay portion and the discharge signal insulation portion and maintains a discharge command signal;

and

the forced discharge circuit portion outputs a discharge state monitoring signal to a vehicle control controller.

9. The electric vehicle inverter apparatus as in claim 6, wherein

the discharge signal latch circuit portion is configured so that an emitter of a single PNP transistor is connected to an anode of the zener diode of the drive circuit portion;

the discharge signal latch circuit portion does not have a function of latching a discharge command signal; and

the discharge signal latch circuit portion is configured to receive a discharge command signal preliminarily latched and to cause the drive circuit portion to operate.

10. The electric vehicle inverter apparatus as in claim 4, wherein

the gate power supply circuit portion is configured so that a discharge restart transistor and a discharge restart resistor series-connected to each other are parallel-connected to the zener diode and the electrolytic capacitor parallel-connected to each other;

and

when receiving a discharge restart signal from a restart command portion of the vehicle control controller just upon completion of a discharge operation, the gate power supply circuit portion turns on the discharge restart transistor and discharges charges charged into the electrolyte capacity.

11. The electric vehicle inverter apparatus as in claim 2, wherein

the power semiconductor element of the discharge circuit portion is replaced with a discharge relay;

an excitation winding of the discharging relay is exited by the drive circuit portion;

one of contacts of the discharge relay is connected to the discharge resistor; and

the other contact of the discharge relay is connected to the discharge current detection resistor.

12. A protection method for an electric vehicle inverter apparatus,

the electric vehicle inverter apparatus comprising:

an inverter portion configured to drive an AC electric motor mechanically connected to a vehicle drive portion of an electric vehicle;

a converter portion configured to convert electric power generated by the AC electric generator which generates electric power by an engine driving force of the electric vehicle into a direct-current voltage within predetermined range of voltages;

an inverter controller configured to control the inverter portion and the converter portion;

a main circuit capacitor connected between DC bus of the inverter and the converter; and

a forced discharge circuit portion configured to discharge electric charges charged into the main circuit capacitor in response to a discharge command signal,

direct-current electric power for the inverter portion being supplied from a high-voltage battery unit which includes an inverter main circuit connection switch, a high-voltage battery and an inrush current suppression circuit configured to suppress an inrush current from the high-voltage battery when the inverter main circuit connection switch is thrown and which is connected to the DC bus,

control power being supplied from a low-voltage battery unit which includes a low-voltage battery and a switch configured to open and close the low-voltage battery,

the electric vehicle inverter apparatus receiving and being controlled according to both of a control signal from a vehicle control controller configured to supervisingly control the electric vehicle and a control signal from a collision detector which is connected between the vehicle control controller and the low-voltage battery and which includes a switch configured to be put into an open state when detecting impact due to a collision of the electric vehicle,

the protection method comprising;

detecting, by the vehicle control controller, an open signal indicating that a switch of the collision detector is opened when the collision detector is operated by the collision of the electric vehicle;

bringing, by the vehicle control controller, the inverter main circuit connection switch of the high-voltage battery unit into an open state,

interrupting, by the vehicle control controller, supply of direct-current electric power of the high-voltage battery to the DC bus portions,

outputting, by the vehicle control controller, a discharge command signal to the forced discharge circuit portion; and

discharging, by the forced discharge circuit portion, electric charges charged into the main circuit capacitor.

13. The protection method for an electric vehicle inverter apparatus as in claim 12, wherein

the forced discharge circuit portion comprises:

a discharge circuit portion including a discharge resistor, a power semiconductor element, and a discharge current detection resistor, which are series-connected between the DC bus;

a discharge resistor overheat protection circuit portion configured to operate by receiving a voltage generated by voltage drop due to discharge current flowing through the discharge current detection resistor as an input thereto;

a gate power supply circuit portion configured to generate drive power for the power semiconductor element from a direct-current voltage between the DC bus;

a drive circuit portion configured to give a drive signal to a control terminal of the power semiconductor element; and

a discharge signal latch circuit portion configured to receive a discharge command signal according to a detection signal from the collision detector and to give a drive signal to the drive circuit portion;

when receiving a discharge command signal according to a detection signal from the collision detector, the discharge signal latch circuit portion maintains an on-signal to the drive circuit portion so that the discharge circuit portion can constantly maintain a discharge operation on-state; and

when a terminal voltage of the main circuit capacitor is lowered to a value close to 0 volt by a discharge operation, and when a power supply voltage of the gate power supply circuit portion is lowered to a value which is equal to or lower than an operable voltage of the drive circuit portion, the discharge operation on-state is canceled.

14. The protection method for an electric vehicle inverter apparatus as in claim 12, wherein

the forced discharge circuit portion comprises:

a DC-DC converter configured to convert a battery voltage supplied from the low-voltage battery into an operating voltage of a control circuit portion;

a storage portion configured to store an output voltage of the DC-DC converter;

a discharge operation command input portion configured to input a detection signal from the collision detector and a discharge signal from the vehicle control controller;

a discharge command delay portion configured to prevent occurrence of chattering of the signal input to the discharge operation command input portion;

a discharge signal insulation portion configured to electrically insulate an output signal from the discharge command delay portion; and

the storage portion has storage capacity sufficient to an extent that a voltage drop due to interruption of a voltage supplied from the low-voltage battery unit can slightly be delayed on collision of the electric vehicle, and can maintain a power supply voltage at which a control circuit portion is operable until a discharge operation of the forced discharge circuit portion is started up.

15. The protection method for an electric vehicle inverter apparatus as in claim 13, wherein

the gate power supply circuit portion comprises a resistor and a zener diode series-connected via a diode between the DC bus, and electrolytic capacitors series-connected to each other and parallel-connected to the resistor and the zener diode, respectively;

and

a zener voltage of the zener diode is higher than an operable voltage of the drive circuit portion, and equal to and lower than an allowable gate voltage of the power semiconductor element.

16. The protection method for an electric vehicle inverter apparatus as in claim 14, wherein

the forced discharge circuit portion is configured so that a discharge command latch portion is provided between the discharge command delay portion and the discharge signal insulation portion and maintains a discharge command signal;

and

the forced discharge circuit portion outputs a discharge state monitoring signal to a vehicle control controller.

17. The protection method for an electric vehicle inverter apparatus as in claim 15, wherein

the gate power supply circuit portion is configured so that a discharge restart transistor and a discharge restart resistor series-connected to each other are parallel-connected to the zener diode and the electrolytic capacitor parallel-connected to each other;

and

when receiving a discharge restart signal from a restart command portion of the vehicle control controller just upon completion of a discharge operation, the gate power supply circuit portion turns on the discharge restart transistor and discharges charges charged into the electrolyte capacity.