Steering power system for electric vehicle and method controlling same

Patent metadata

Field	Value
Publication number	US-9963166-B2
Application number	US-201515316069-A
Country	US
Kind code	B2
Filing date	Nov 13, 2015
Priority date	Nov 17, 2014
Publication date	May 8, 2018
Grant date	May 8, 2018

Abstract

A steering power system for an electric vehicle and a method for controlling same are provided. The steering power system includes: a steering motor; a steering motor controller, configured to control the steering motor; a high voltage power battery, configured to output a first voltage; a low voltage storage battery, configured to output a second voltage; a buck DC-DC converter, configured to convert the first voltage into the second voltage for being supplied to the low voltage storage battery when a high voltage system works; and a boost DC-DC converter, configured to convert the second voltage into the first voltage. When the high voltage system has an abnormal power failure, the boost DC-DC converter converts the second voltage outputted from the low voltage storage battery into the first voltage for being supplied to the steering motor controller.

First claim

What is claimed is:

1. A steering power system for an electric vehicle, comprising:
a steering motor;
a steering motor controller, connected with the steering motor and configured to control the steering motor;
a high voltage power battery, configured to output a first voltage;
a low voltage storage battery, configured to output a second voltage lower than the first voltage;
a buck DC-DC converter, connected with the high voltage power battery and the low voltage storage battery respectively, and configured to convert the first voltage outputted from the high voltage power battery into the second voltage for being supplied to the low voltage storage battery, when a high voltage system of the electric vehicle is working;
a boost DC-DC converter, connected with the low voltage storage battery and the steering motor controller respectively, and configured to convert the second voltage outputted from the low voltage storage battery into the first voltage, and
a battery manager, connected with the steering motor controller, the buck DC-DC converter and the boost DC-DC converter respectively via a CAN bus, and configured to send a power off notification message to control the high voltage system of the electric vehicle to stop working, wherein the steering motor controller detects that the voltage of the direct current bus capacitor steadily drops,
wherein when the high voltage system of the electric vehicle has an abnormal power failure, the boost DC-DC convertor converts the second voltage outputted from the low voltage storage battery into the first voltage for being supplied to the steering motor controller, and the battery manager is configured to control the boost DC-DC converter and the buck DC-DC converter to work simultaneously so that the boost DC-DC converter and the high voltage power battery to supply power to the steering motor controller simultaneously, when the high voltage system of the electric vehicle is working.

2. The steering power system of claim 1 , wherein the steering motor controller comprises: a direct current bus capacitor, an inverter, and a detecting unit;
wherein the direct current bus capacitor is connected with direct current input terminals of the inverter in parallel, and the detecting unit is configured to detect a voltage of the direct current bus capacitor.

3. The steering power system of claim 2 , wherein input terminals of the buck DC-DC converter are connected with the high voltage power battery in parallel via a first DC-DC connector, output terminals of the buck DC-DC converter are connected with the low voltage storage battery in parallel, input terminals of the boost DC-DC converter are connected with the low voltage storage battery in parallel, output terminals of the boost DC-DC converter are connected with the direct current bus capacitor in parallel, and the high voltage power battery is connected with the direct current bus capacitor in parallel.

4. The steering power system of claim 2 , further comprising:
a steering contactor, having a first terminal connected with a first terminal of the high voltage power battery and a second terminal; and
a diode, having an anode connected with the second terminal of the steering contactor and a cathode connected with a first terminal of the direct current bus capacitor, wherein a second terminal of the direct current bus capacitor is connected with a second terminal of the high voltage power battery.

5. The steering power system of claim 4 , further comprising:
a steering pre-charging contactor having a first terminal connected with the first terminal of the steering contactor and a second terminal; and
a pre-charging resistor having a first terminal connected with the second terminal of the steering pre-charging contactor and a second terminal connected with the cathode of the diode.

6. The steering power system of claim 2 , wherein input terminals of the buck DC-DC converter are connected with the high voltage power battery in parallel via a second DC-DC connector, output terminals of the buck DC-DC converter are connected with the low voltage storage battery in parallel, input terminals of the boost DC-DC converter are connected with the low voltage storage battery in parallel, and output terminals of the boost DC-DC converter are connected with the direct current bus capacitor in parallel.

7. The steering power system of claim 1 , wherein the battery manager is further configured to:
control the high voltage power battery to supply power to the steering motor controller independently, and control the buck DC-DC converter to work when the high voltage system of the electric vehicle is working;
control the boost DC-DC converter to be in a standby mode; and
determine that the high voltage system of the electric vehicle has the abnormal power failure when the voltage of the direct current bus capacitor is less than a first predetermined voltage and the power off notification message is not sent by the battery manager, and control the boost DC-DC converter to work.

8. The steering power system of claim 1 , wherein the battery manager is further configured to:
control the boost DC-DC converter to supply power to the steering motor controller independently, when the high voltage system of the electric vehicle has the abnormal power failure.

9. The steering power system of claim 1 , wherein the low voltage storage battery is further configured to supply power to a low voltage system of the electric vehicle.

10. The steering power system of claim 1 , wherein the battery manager is further configured to:
control the buck DC-DC converter to convert the first voltage outputted from the high voltage power battery into the second voltage to charge the low voltage storage battery, control the boost DC-DC converter to convert the second voltage outputted from the low voltage storage battery into the first voltage for being supplied to the steering motor controller, when the high voltage system of the electric vehicle is working; and
control the boost DC-DC convertor to convert the second voltage outputted from the low voltage storage battery into the first voltage for being supplied to the steering motor controller, when the high voltage system of the electric vehicle has an abnormal power failure.

11. A method for controlling a steering power system for an electric vehicle, comprising:
providing a first voltage by a high voltage power battery;
converting the first voltage provided by the high voltage power battery into a second voltage lower than the first voltage and supplying the second voltage to a low voltage storage battery by a buck DC-DC converter, when a high voltage system of the electric vehicle is working;
converting the second voltage provided by the low voltage storage battery into the first voltage and supplying the first voltage to a steering motor controller by a boost DC-DC converter, when the high voltage system of the electric vehicle has an abnormal power failure, and
controlling the boost DC-DC converter and the buck DC-DC converter to work simultaneously so as to control the boost DC-DC converter and the high voltage power battery to supply power to the steering motor controller simultaneously.

12. The method of claim 11 , further comprising:
detecting a voltage of a direct current bus capacitor by the steering motor controller.

13. The method of claim 12 , wherein
if the voltage of the direct current bus capacitor is less than a first predetermined voltage and a power off notification message is not sent by a battery manager, the battery manager determines the high voltage system of the electric vehicle has the abnormal power failure, a

Assignees

• Byd Co Ltd

Inventors

• Xu Jinze
• Wu Xingchi
• Luo Wengang
• Zhang Chao
• Wang Hongjun
• Luan Zhenpai

Classifications

• B60L1/00

  Supplying electric power to auxiliary equipment of vehicles (circuit arrangements for charging batteries H02J7/00) · CPC title

• B60L2210/14

  Boost converters · CPC title

• B60Y2200/91

  Electric vehicles · CPC title

• B60R16/03

  for supply of electrical power to vehicle subsystems {or for (circuit arrangements for charging batteries H02J7/00)} · CPC title

• B62D5/046

  Controlling the motor · CPC title