Driving circuit for hybrid electric vehicle and controlling method thereof
There is provided a driving circuit for a hybrid electric vehicle, including a first battery and a second battery, an inverter for converting an applied voltage to the form of direct current (DC) or alternating current (AC) according to the operating mode of the motor, a converter operating in a boost mode or a buck mode according to the operating mode of the motor, and a processor for comparing a voltage (V B1 ) of the first battery and a voltage of a DC-link capacitor and controls electrical connection between the first battery, and the inverter and the converter during start-up, wherein the DC-link capacitor is connected in parallel to the first battery, the inverter, and the converter.
1. A driving circuit for a hybrid electric vehicle, comprising:
a first battery and a second battery that are charged or discharged with a predetermined voltage according to an operating mode of a motor;
an inverter connected in series between the motor and the first battery and for converting an applied voltage to the form of direct current (DC) or alternating current (AC) according to the operating mode of the motor;
a converter connected in parallel between the second battery and the first battery and operating in a boost mode or a buck mode according to the operating mode of the motor; and
a processor for comparing a voltage (VB 1 ) of the first battery and a voltage of a DC-link capacitor and for controlling electrical connection between the first battery, the inverter and the converter during start-up, wherein the DC-link capacitor is connected in parallel to the first battery, the inverter, and the converter, and wherein the converter is a bidirectional DC-DC converter that is driven in the boost mode for boosting a voltage of the second battery and for supplying the voltage to the motor or in the buck mode for bucking a voltage supplied from the motor and for supplying the voltage to the second battery.
2. The driving circuit of claim 1 , wherein the first battery includes a power switch for mutually and electrically connecting the first battery to the inverter and the converter through a switching operation.
3. The driving circuit of claim 2 , wherein the DC-link capacitor includes a first capacitor connected in parallel to the inverter and a second capacitor connected in parallel to the converter.
4. The driving circuit of claim 3 , wherein the processor controls the switching operation of the power switch according to a comparison result between the voltage (V B1 ) of the first battery and the voltage of the DC-link capacitor.
5. The driving circuit of claim 4 , wherein the processor controls the converter to be driven in the boost mode and controls the switching operation of the power switch of the first battery when the voltage (V B1 ) of the first battery and the voltage of the DC-link capacitor are different.
6. The driving circuit of claim 5 , wherein the processor charges the voltage the DC-link capacitor through the boost mode of the converter, and turns on the power switch of the first battery when the voltage of the DC-link capacitor reaches the voltage (V B1 ) of the first battery.
7. The driving circuit of claim 2 , wherein the processor includes:
a battery controller for controlling the first battery and the switching operation of the power switch;
a converter controller for controlling a driving mode of the converter;
an inverter controller for controlling driving of the inverter; and
a main controller for controlling the battery controller, the converter controller, and the inverter controller to control the switching operation of the power switch according to a comparison result between the voltage of the first battery and the voltage of the DC-link capacitor during start-up.
8. The driving circuit of claim 7 , wherein the main controller controls the battery controller, the inverter controller, and the converter controller through controller area network (CAN) communication.
9. The driving circuit of claim 7 , wherein:
the main controller detects the voltage (V B1 ) of the first battery through the battery controller during start-up of the motor, controls the driving mode of the converter to charge a voltage of the DC-link capacitor through the converter controller when the voltage (V B1 ) of the first battery is lower than the voltage of the DC-link capacitor, and turns on the power switch through the battery controller when the voltage of the DC-link capacitor reaches the voltage (V B1 ) of the first battery.
10. A controlling method of a driving circuit for a hybrid electric vehicle, the hybrid electric vehicles comprising:
a first battery and a second battery that are charged or discharged with a predetermined voltage accordina to an operating mode of a motor;
an inverter connected in series between the motor and the first battery and for converting an applied voltage to the form of direct current (DC) or alternating current (AC) according to the operating mode of the motor;
a converter connected in parallel between the second battery and the first battery and operating in a boost mode or a buck mode according to the operating mode of the motor; and
a processor for comparing a voltage (VB 1 ) of the first battery and a voltage of a DC-link capacitor and for controlling electrical connection between the first battery, the inverter and the converter during start-up,
wherein the DC-link capacitor is connected in parallel to the first battery, the inverter, and the converter, and wherein the converter is a bidirectional DC-DC converter that is driven in the boost mode for boosting a voltage of the second battery and for supplying the voltage to the motor or in the buck mode for bucking a voltage supplied from the motor and for supplying the voltage to the second battery,
the controlling method comprising:
detecting the voltage (VB 1 ) of the first battery and the voltage of the DC-link capacitor during start-up; comparing the voltage (VB 1 ) of the first battery and the voltage of the DC-link capacitor; and controlling a switching operation of a power switch of the first battery according to the comparison result between the voltage (VB 1 ) of the first battery and the voltage of the DC-link capacitor.
11. The controlling method of claim 10 , wherein the controlling includes: driving the converter in the boost mode when the voltage (VB 1 ) of the first battery is different from the voltage of the DC-link capacitor; and turning on the power switch of the first battery when the voltage (VB 1 ) of the first battery is the
same as the voltage of the DC-link capacitor.
12. The controlling method of claim 11 , wherein the driving includes:
charging the voltage of the DC-link capacitor through the boost mode of the converter;
comparing the voltage of the DC-link capacitor with the voltage of the first battery; and
turning on the power switch of the first battery when the voltage of the DC-link capacitor reaches the voltage of the first battery.