Forced discharge circuit of battery charger for electric vehicle, battery charger for electric vehicle, and electric vehicle having function of the battery charge

• US 9,397,496 B2
• Filed: 03/14/2014
• Issued: 07/19/2016
• Est. Priority Date: 03/18/2013
• Status: Active Grant

• Current Assignee: HL Klemove Corporation
• Original Assignee: Mando Corporation
• Inventors: Kang, Jae Jun, Yoo, Seog Jeong, Noh, Dong Yoon
• Primary Examiner(s): Tso, Edward
• Application Number:
  US14/213,552
• Publication Number:
  US 20140266044A1
• Time in Patent Office: 858 Days
• Field of Search: 320/104, 320/127, 320/135
• US Class Current: 1/1
• CPC Class Codes: B60L 53/20 characterised by converters located in the vehicle
• CPC Class Codes: H02H 9/045 adapted to a particular application and not provided for elsewhere
• CPC Class Codes: H02M 1/0058 by employing soft switching techniques, i.e. commutation of transistors when applied voltage is zero or when current flow is zero using an auxiliary actively switched resonant commutation circuit connected to an intermediate DC voltage or between two push-pull branches of an inverter bridge H02M7/4811; in resonant inverters H02M7/4815; in inverters operating from a resonant DC source H02M7/4826
• CPC Class Codes: H02M 1/007 Plural converter units in cascade push-pull DC/DC converters with pre-regulator H02M3/3374; DC-AC converters following a DC-DC stage including a high frequency transformer H02M7/4807; DC-AC converters following a DC-DC conversion stage generating periodically varying voltages H02M7/4826
• CPC Class Codes: H02M 3/01 Resonant DC/DC converters
• CPC Class Codes: H02M 3/33571 Half-bridge at primary side of an isolation transformer
• CPC Class Codes: H02M 3/33573 Full-bridge at primary side of an isolation transformer
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/92 Energy efficient charging or discharging systems for batteries, ultracapacitors, supercapacitors or double-layer capacitors specially adapted for vehicles
• CPC Class Codes: Y02T 90/12 Electric charging stations
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles

Abstract

Provided is a forced discharge circuit of a battery charger for an electric vehicle, which is capable of forcibly discharging a high voltage in accordance with the electric safety code for electric vehicles when the function of the battery charger is stopped. A forced discharge circuit of a battery charger for an electric vehicle, which discharges a high voltage applied to the battery charger that converters commercial power to charge a vehicle battery, includes: a micro control unit (MCU) configured to generate a control signal according to a charge state of the battery charger; a discharge resistor connected in parallel to the battery charger; and a relay connected in series to the discharge resistor and configured to operate in an on or off state according to the control signal of the MCU.

Claims

1. A forced discharge circuit of a battery charger for an electric vehicle, which discharges a high voltage applied to the battery charger that converters commercial power to charge a vehicle battery, the forced discharge circuit comprising:

a micro control unit (MCU) configured to generate a control signal according to a charge state of the battery charger;

a discharge resistor connected in parallel to the battery charger;

a relay connected in series to the discharge resistor and configured to operate in an on or off state according to the control signal of the MCU; and

an insulation control device provided between the MCU and the relay to control a current flow according to the control signal of the MCU.

2. The forced discharge circuit according to claim 1, wherein the relay is a normal close (NC) type relay configured to maintain an open state when a voltage is applied and maintain a close state when no voltage is applied.

3. The forced discharge circuit according to claim 1, wherein the MCU outputs a LOW signal to the insulation control device when the function of the battery charger is stopped.

4. The forced discharge circuit according to claim 1, wherein the insulation control device is a photo coupler.

5. The forced discharge circuit according to claim 1, wherein the insulation control device is a pulse transformer.

6. The forced discharge circuit according to claim 1, further comprising a field effect transistor (FET) provided between the insulation control device and the relay to control a current flowing into the relay according to the current flow of the insulation control device.

7. A battery charger for an electric vehicle, comprising:

an AC power supply configured to supply commercial power;

a filter/rectifier configured to rectify the commercial power supplied from the AC power supply into a DC voltage;

a converter configured to convert the DC voltage output from the filter/rectifier into a voltage that is chargeable to a battery; and

a discharge circuit connected in parallel to the converter and configured to forcibly discharge a high voltage applied to the converter when input power is removed from the AC power supply;

wherein the discharge circuit comprises;

an micro control unit (MCU) configured to generate a control signal according to a charge state of the battery charger;

a discharge resistor connected in parallel to the battery charger;

a relay connected in series to the discharge resistor and configured to operate in an on or off state according to the control signal of the MCU; and

an insulation control device provided between the MCU and the relay to control a current flow according to the control signal of the MCU.

8. The battery charger according to claim 7, wherein the relay is a normal close (NC) type relay configured to maintain an open state when a voltage is applied and maintain a close state when no voltage is applied.

9. The battery charger according to claim 7, wherein the MCU outputs a LOW signal to the insulation control device when the function of the battery charger is stopped.

10. The battery charger according to claim 7, wherein the insulation control device is a photo coupler.

11. The battery charger according to claim 7, wherein the insulation control device is a pulse transformer.

12. The battery charger according to claim 7, wherein the discharge circuit further comprises a field effect transistor (FET) provided between the insulation control device and the relay to control a current flowing into the relay according to the current flow of the insulation control device.

13. The battery charger according to claim 7, wherein the converter comprises:

a power factor correction circuit having a power factor correction function and configured to convert the power of the commercial power;

an line level control (LLC) converter configured to switch a current supplied from the power factor correction circuit through LLC to convert the current into a pulse signal; and

a buck converter configured to convert the current output from the LLC converter into a voltage that is chargeable to a battery.

14. The battery charger according to claim 13, wherein the discharge circuit is connected in parallel between the filter/rectifier and the power factor correction circuit.

15. The battery charger according to claim 13, wherein the discharge circuit is connected in parallel between the power factor correction circuit and the LLC converter.

16. The battery charger according to claim 13, wherein the discharge charger is connected in parallel between the LLC converter and the buck converter.

17. The battery charger according to claim 13, wherein the discharge charger is connected in parallel between the buck converter and the battery.

18. In a control system of a battery charger for an electric vehicle, which controls a charging operation of the battery charger that is supplied with power from an electric vehicle supply equipment and charges a vehicle driving battery built in the electric vehicle, an electric vehicle including an onboard battery charger and having a charging function, the electric vehicle comprising:

an onboard battery charger built in the electric vehicle and configured to be supplied with power from the electric vehicle supply equipment to charge the battery; and

the battery configured to be supplied with power from the onboard battery charger and be charged,

wherein the onboard battery charger comprises;

an AC power supply configured to supply commercial power;

a filter/rectifier configured to rectify the commercial power supplied from the AC power into a DC voltage;

a converter configured to convert the DC voltage output from the filter/rectifier into a voltage that is chargeable to a battery; and

a discharge circuit connected in parallel to the converter and configured to forcibly discharge a high voltage applied to the converter when input power is removed from the AC power supply,

wherein the discharge circuit comprises;

an micro control unit (MCU) configured to generate a control signal according to a charge state of the battery charger;

a discharge resistor connected in parallel to the battery charger;

a relay connected in series to the discharge resistor and configured to operate in an on or off state according to the control signal of the MCU;

an insulation control device provided between the MCU and the relay to control a current flow according to the control signal of the MCU; and

a field effect transistor (FET) provided between the insulation control device and the relay to control a current flowing into the relay according to the current flow of the insulation control device.