Electric vehicle and active discharging system for electric vehicle
An active discharging system for an electric vehicle and an electric vehicle including the same are provided. The active discharging system includes a power battery; a bus capacitor; a charge-discharge socket; a bidirectional DC/DC module; a driving control switch; a bidirectional DC/AC module; a motor control switch connected with the bidirectional DC/AC module and a motor; a charge-discharge control module connected with the bidirectional DC/AC module and the charge-discharge socket; and a controller module configured to control the driving control switch, the motor control switch and the charge-discharge control module according to a current operation mode of the active discharging system, to control the bus capacitor to continue charging the power battery after a charge is finished, and to control the bus capacitor to continue discharging after a discharge is finished until a voltage across the bus capacitor is less than a first predetermined value.
1. An active discharging system for an electric vehicle, comprising:
a power battery;
a bus capacitor;
a charge-discharge socket;
a bidirectional DC/DC module having a first DC terminal connected with a first terminal of the power battery and a second DC terminal connected with a second terminal of the power battery, wherein the first DC terminal of the bidirectional DC/DC module is a common DC terminal for an input to and an output from the bidirectional DC/DC module;
a driving control switch having a first terminal connected with the second terminal of the power battery and a second terminal connected with a third DC terminal of the bidirectional DC/DC module;
a bidirectional DC/AC module having a first DC terminal connected with the second terminal of the driving control switch and a second DC terminal connected with the first terminal of the power battery;
a motor control switch having a first terminal connected with an AC terminal of the bidirectional DC/AC module and a second terminal connected with a motor;
a charge-discharge control module having a first terminal connected with the AC terminal of the bidirectional DC/AC module and a second terminal connected with the charge-discharge socket; and
a controller module connected with the driving control switch, the motor control switch and the charge-discharge control module respectively, and configured to control the driving control switch, the motor control switch and the charge-discharge control module according to a current operation mode of the active discharging system, to control the bus capacitor to continue charging the power battery after a charge is finished, and to control the bus capacitor to continue discharging after a discharge is finished until a voltage across the bus capacitor is less than a first predetermined value.
2. The active discharging system according to claim 1 , wherein after the charge is finished, the controller module controls the charge-discharge control module and the motor control switch to turn off, and controls the driving control switch in such a way that the bus capacitor charges the power battery via the bidirectional DC/DC module.
3. The active discharging system according to claim 1 , wherein after the discharge is finished, the controller module controls the motor control switch to turn off, and controls the driving control switch in such a way that the bus capacitor and a first capacitor in the bidirectional DC/DC module discharge via the bidirectional DC/AC module, the charge-discharge control module and the charge-discharge socket so as to make the voltage across the bus capacitor less than a second predetermined value, in which the second predetermined value is less than the first predetermined value.
4. The active discharging system according to claim 1 , wherein when the current operation mode of the active discharging system is a driving mode, the controller module controls the driving control switch to turn on to stop the bidirectional DC/DC module, controls the motor control switch to turn on, and controls the charge-discharge control module to turn off.
5. The active discharging system according to claim 4 , wherein when the current operation mode of the active discharging system is a charge-discharge mode, the controller module controls the driving control switch to turn off to start the bidirectional DC/DC module, controls the motor control switch to turn off, and controls the charge-discharge control module to turn on to start the bidirectional DC/AC module.
6. The active discharging system according to claim 1 , further comprising:
a first pre-charging control module having a first terminal connected with the second terminal of the power battery and a second terminal connected with the second DC terminal of the bidirectional DC/DC module, and configured to pre-charge a first capacitor in the bidirectional DC/DC module and the bus capacitor connected between the first DC terminal and the third DC terminal of the bidirectional DC/DC module.
7. The active discharging system according to claim 6 , wherein the first pre-charging control module comprises:
a first switch having a first terminal connected with the second DC terminal of the bidirectional DC/DC module;
a first resistor having a first terminal connected with a second terminal of the first switch and a second terminal connected with the second terminal of the power battery; and
a second switch, connected in parallel with the first resistor and the first switch which are connected in series,
wherein when the active discharging system starts, the controller module controls the first switch to turn on to pre-charge the first capacitor in the bidirectional DC/DC module and the bus capacitor; and when a voltage across the bus capacitor is a predetermined multiple of a voltage of the power battery, the controller module controls the first switch to turn off and controls the second switch to turn on.
8. The active discharging system according to claim 1 , wherein the bidirectional DC/DC module comprises:
a first switching transistor and a second switching transistor connected in series, and connected between the first DC terminal and the third DC terminal of the bidirectional DC/DC module, and controlled by the controller module, in which a first node is defined between the first switching transistor and the second switching transistor;
a first diode connected with the first switching transistor in inverse-parallel;
a second diode connected with the second switching transistor in inverse-parallel;
a first inductor having a first terminal connected with the first node and a second terminal connected with the second terminal of the power battery; and
a first capacitor having a first terminal connected with the second terminal of the first inductor and a second terminal connected with the first terminal of the power battery.
9. The active discharging system according to claim 1 , further comprising:
a leakage current reducing module connected between the first DC terminal and the third DC terminal of the bidirectional DC/DC module.
10. The active discharging system according to claim 9 , wherein the leakage current reducing module comprises:
a second capacitor and a third capacitor, in which the second capacitor has a first terminal connected with a first terminal of the third capacitor and a second terminal connected with the third DC terminal of the bidirectional DC/DC module, the third capacitor has a second terminal connected with the first DC terminal of the bidirectional DC/DC module, and a second node is defined between the second capacitor and the third capacitor.
11. The active discharging system according to claim 10 , further comprising:
a filtering module connected between the bidirectional DC/AC module and the charge-discharge control module.
12. The active discharging system according to claim 11 , further comprising:
a filtering control module connected between the second node and the filtering module, in which when the current operation mode of the active discharging system is the driving mode, the controller module controls the filtering control module to turn off.
13. The active discharging system according to claim 11 , further comprising:
an EMI-filter module connected between the charge-discharge socket and the charge-discharge control module.
14. The active discharging system according to claim 13 , further comprising:
a second pre-charging control module connected with the charge-discharge control module in parallel and configured to pre-charge a capacitor in the filtering module.
15. The active discharging system according to claim 1 , wherein the charge-discharge control module comprises:
a three-phase switch and/or a single-phase switch configured to implement a three-phase charge or a single-phase charge.
16. An electric vehicle comprising an active discharging system, the active discharging system comprising:
a power battery;
a bus capacitor;
a charge-discharge socket;
a bidirectional DC/DC module having a first DC terminal connected with a first terminal of the power battery and a second DC terminal connected with a second terminal of the power battery, wherein the first DC terminal of the bidirectional DC/DC module is a common DC terminal for an input to and an output from the bidirectional DC/DC module;
a driving control switch having a first terminal connected with the second terminal of the power battery and a second terminal connected with a third DC terminal of the bidirectional DC/DC module;
a bidirectional DC/AC module having a first DC terminal connected with the second terminal of the driving control switch and a second DC terminal connected with the first terminal of the power battery;
a motor control switch having a first terminal connected with an AC terminal of the bidirectional DC/AC module and a second terminal connected with a motor;
a charge-discharge control module having a first terminal connected with the AC terminal of the bidirectional DC/AC module and a second terminal connected with the charge-discharge socket; and
a controller module connected with the driving control switch, the motor control switch and the charge-discharge control module respectively, and configured to control the driving control switch, the motor control switch and the charge-discharge control module according to a current operation mode of the active discharging system, to control the bus capacitor to continue charging the power battery after a charge is finished, and to control the bus capacitor to continue discharging after a discharge is finished until a voltage across the bus capacitor is less than a first predetermined value.
17. The electric vehicle according to claim 16 , wherein after the charge is finished, the controller module controls the charge-discharge control module and the motor control switch to turn off, and controls the driving control switch in such a way that the bus capacitor charges the power battery via the bidirectional DC/DC module.
18. The electric vehicle according to claim 16 , wherein after the discharge is finished, the controller module controls the motor control switch to turn off, and controls the driving control switch in such a way that the bus capacitor and a first capacitor in the bidirectional DC/DC module discharge via the bidirectional DC/AC module, the charge-discharge control module and the charge-discharge socket so as to make the voltage across the bus capacitor less than a second predetermined value, in which the second predetermined value is less than the first predetermined value.
19. The electric vehicle according to claim 16 , wherein when the current operation mode of the active discharging system is a driving mode, the controller module controls the driving control switch to turn on to stop the bidirectional DC/DC module, controls the motor control switch to turn on, and controls the charge-discharge control module to turn off.
20. The electric vehicle according to claim 19 , wherein when the current operation mode of the active discharging system is a charge-discharge mode, the controller module controls the driving control switch to turn off to start the bidirectional DC/DC module, controls the motor control switch to turn off, and controls the charge-discharge control module to turn on to start the bidirectional DC/AC module.