Electronic parking brake system

1. An electronic parking brake system, comprising:

a first ECU (electronic control unit) connected to a plurality of motors and a second ECU connected to the plurality of motors for providing a driving force to a wheel to control the plurality of motors,

wherein the second ECU comprises:

a power reserve system operable to store a power supplied from a battery and supply, instead of the battery, the stored power to the second ECU;

a switch connected to the first ECU, the second ECU, and the plurality of motors and operable to switch the plurality of motors to be connected with the first ECU via the switch or the plurality of motors to be connected with the second ECU via the switch, based on an operating state of the first ECU; and

a second MCU for identifying the operating state of the first ECU, controlling the switch to connect the plurality of motors from the first ECU to the second ECU based on the operating state being an inactive state, and controlling the plurality of motors through the power stored in the power reserve system.

2. The electronic parking brake system of claim 1 , wherein the power reserve system comprises a super capacitor for charging a first power supplied from the battery and discharging the first power based on a power supply signal.

3. The electronic parking brake system of claim 2 , wherein the switch is a first switch,

wherein the power supply signal includes a first power supply signal and a second power supply signal,

wherein a third switch, which is disposed between the super capacitor and the first switch and configured to switch to a first state for applying a braking force to the plurality of motors by receiving the first power supply signal, or to a second state for releasing a braking force applied by the plurality of motors by receiving the second power supply signal, is included, and

wherein the second MCU transmits the first power supply signal or the second power supply signal to the third switch to control the plurality of motors.

4. The electronic parking brake system of claim 3 , wherein the super capacitor discharges the first power based on the first power supply signal, and charges the first power from the battery based on the second power supply signal.

5. The electronic parking brake system of claim 3 , wherein the second ECU further comprises an ASIC,

wherein the ASIC identifies a wheel speed based on a detection signal received from a WSS in response to receiving a braking signal, and transmits the first power supply signal to the third switch, if the wheel speed is less than or equal to a predefined value.

6. The electronic parking brake system of claim 2 , wherein the power reserve system further comprises a regulator for supplying the first power which is constant to the super capacitor.

7. The electronic parking brake system of claim 2 , wherein the switch is a first switch,

wherein a second switch, which is disposed between the super capacitor and the first switch and configured to receive the power supply signal and switch to an on state, is included, and

wherein the second MCU transmits the power supply signal to the second switch to control the plurality of motors.

8. The electronic parking brake system of claim 7 , wherein when a braking signal is received, the second MCU identifies a wheel speed based on a detection signal received from a WSS, and transmits the power supply signal to the second switch, if the wheel speed is less than or equal to a predefined value.

9. The electronic parking brake system of claim 7 , wherein the second ECU further comprises an ASIC, and

wherein the ASIC identifies a wheel speed based on a detection signal received from a WSS in response to receiving a braking signal, and transmits the power supply signal to the second switch, if the wheel speed is less than or equal to a predefined value.

10. The electronic parking brake system of claim 1 , wherein the second MCU identifies the operating state by receiving information about the operating state from the first ECU, and transmits a switching change signal to the switch according to the operating state.

11. The electronic parking brake system of claim 1 , wherein the switch is a first switch, and

wherein the first ECU comprises:

a motor driving circuit respectively connected to the plurality of motors to drive a plurality of actuators for controlling the plurality of motors; and

a first MCU for controlling the plurality of motors through the motor driving circuit based on receiving a braking signal.

12. The electronic parking brake system of claim 11 , wherein the second MCU performs communication with the first MCU periodically or in real time through a data bus.

13. The electronic parking brake system of claim 2 , wherein the power reserve system further comprises a power protection circuit to supply the first power which is constant to the super capacitor.

14. The electronic parking brake system of claim 13 , wherein the power reserve system further comprises a step-up converter for increasing a voltage of the first power charged in the super capacitor to a second power which voltage is higher than the voltage of the first power.

15. A method for controlling an electronic parking brake system comprising a first ECU (electronic control unit) connected to a plurality of motors and a second ECU connected to the plurality of motors for providing a driving force to a wheel to control the plurality of motors, the method comprising the steps of:

storing a power supplied from the battery in a power reserve system of the second ECU, wherein the power reserve system is operable to supply, instead of the battery, the stored power to the second ECU;

identifying an operating state of the first ECU;

controlling a switch, connected to the first ECU, the second ECU, and the plurality of motors, so as to switch from a first connection state in which the plurality of motors is connected with the first ECU via the switch to a second connection state in which the plurality of motors is connected with the second ECU via the switch, based on the operating state being an inactive state; and

controlling the plurality of motors through the power stored in the second ECU.

16. The method of claim 15 , wherein the power reserve system comprises a super capacitor for charging a first power supplied from the battery and discharging the first power based on a power supply signal.

17. The method of claim 16 , wherein the switch is a first switch,

wherein a second switch, which is disposed between the super capacitor and the first switch and configured to receive the power supply signal and switch to an on state, is included, and

wherein the step of controlling of the plurality of motors comprises controlling the plurality of motors by transmitting the power supply signal to the second switch.

18. The method of claim 17 , wherein the step of controlling the plurality of motors comprises the steps of:

identifying a wheel speed based on a detection signal received from WSS when a braking signal is received; and

transmitting the power supply signal to the second switch if the wheel speed is less than or equal to a predefined value.

19. The method of claim 16 , wherein the switch is a first switch,

wherein the power supply signal includes a first power supply signal and a second power supply signal,

wherein a third switch, which is disposed between the super capacitor and the first switch and configured to switch to a first state for applying a braking force to the plurality of motors by receiving the first power supply signal, or to a second state for releasing a braking force applied by the plurality of motors by receiving the second power supply signal, is included, and

wherein the step of controlling the plurality of motors comprises controlling the plurality of motors by transmitting the first power supply signal or the second power supply signal to the third switch.

20. The method of claim 16 , wherein the power reserve system further comprises a regulator for supplying the first power which is constant to the super capacitor.