Electric automobile and discharge protection circuit thereof

Abstract

The invention discloses an electric automobile and a discharge protection circuit thereof. The circuit comprises a discharge branch and a time delay switch, wherein the discharge branch is connected in parallel with a direct current bus power supply of the electric automobile, the discharge branch comprises a discharge resistor and a discharge switch which are connected in series, and the discharge switch is conducted when the direct current bus power supply releases voltage, and when the discharge switch is switched on, the direct current bus power supply and the ground form a loop through the discharge resistor and the discharge switch; and the time delay switch is connected with the discharge switch, and the time delay switch is used for turning off the discharge switch when the discharge switch is continuously turned on for more than a preset delay time. Even if the low voltage of the discharge control unit is powered down due to external reasons and the high voltage of the directcurrent bus battery is still continuous, the first switch included in the discharge branch can be turned off through the time delay switch, the first switch is prevented from continuously releasing the voltage of the high-voltage battery, long-time large-current operation is avoided, and the first switch is ensured not to be burnt out.

Description

technical field [0001] The invention belongs to the field of electric vehicles, in particular to an electric vehicle and a discharge protection circuit thereof. Background technique [0002] The energy storage capacitor at the bus end of the motor controller for new energy vehicles is connected in parallel with the DC bus power supply to limit or buffer current. When the electric vehicle is in normal operation, a certain amount of electricity is stored on the energy storage capacitor at the bus end. In order to improve the personal safety of electric vehicle drivers or maintenance personnel, it is necessary to quickly release the energy stored in the energy storage capacitor at the bus end after the electric vehicle is turned off and out of service. Below the safe power level. [0003] At present, a discharge circuit for discharging the energy storage capacitor at the bus end can be set up in an electric vehicle. A general discharge circuit includes two discharge branches t...

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Problems solved by technology

However, in an abnormal situation, there is a hidden danger in this circuit, that is, if the low voltage of the discharge control unit causes power failure due to external reasons, the high voltage of the DC bus battery still continues at this time, which will make the above-mentioned other discharge branch circuit The included switch tube continuously releases the voltage of the high-voltage battery, and runs at high current for a long time, causing the switch tube to burn out

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