Overvoltage Protection Method of HVDC System

Abstract

The invention discloses an overvoltage protection method of a high-voltage direct current system. Once a high-tension battery is disconnected with the high-voltage direct current system, a motor controller is in a passive feedback mode and monitors voltage of a high-voltage direct current network in real time. Once the voltage of the high-voltage direct current network is larger than or equal to the maximum allowing voltage, the motor controller is in an initiative short circuit mode. At the same time, at least one auxiliary discharge device is opened. Once the voltage of the high-voltage direct current network is less than the maximum allowing voltage, the motor controller is in the passive feedback mode. Once the voltage of the high-voltage direct current network is less than or equal to the minimum allowing voltage, all auxiliary discharge devices are closed. Under the condition of breakdown of disconnection of the high-tension battery, the existing motor controller is only provided with a safe mode. The overvoltage protection method of the high-voltage direct current system divides the safe mode into the passive feedback mode and the initiative short circuit mode assisting with an auxiliary discharge mode of the high-voltage direct current system, and thereby the overvoltage protection method of the high-voltage direct current system has the advantages of effectively solving the problem of overhigh voltage of the high-voltage direct current network of a new energy automobile and reducing risk of equipment trouble.

Description

technical field [0001] This application relates to a protection method for a high-voltage DC system in a new energy vehicle (pure electric vehicle, hybrid electric vehicle, etc.). Background technique [0002] see figure 1 , which is a simplified schematic diagram of a high-voltage DC system in a new energy vehicle. The high voltage direct current system includes a high voltage battery 10 , a motor controller 20 , a permanent magnet synchronous motor 30 and an auxiliary discharge device 40 . [0003] The high-voltage battery 10 outputs high-voltage direct current to the motor controller 20 and the auxiliary discharge device 40 to provide energy. The high-voltage battery 10 can also obtain an input high-voltage direct current from the motor controller 20 for charging. [0004] The DC terminal of the motor controller 20 is connected to the high-voltage battery 10, and the AC terminal is connected to the three-phase AC port of the permanent magnet synchronous motor 30 to dri...

AI Technical Summary

Problems solved by technology

At this time, once the permanent magnet synchronous motor 30 is driven at high speed, it will be rectified by the diode in the motor controller 20, so that the voltage of the high-voltage DC network 50 is too high, which may cause equipment damage

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