Overcurrent protection system of motor controller of electric vehicle

Abstract

The present invention provides an overcurrent protection system of a motor controller of an electric vehicle, belonging to the field of the electric vehicle motor drive control technology. The overcurrent protection system of the motor controller of the electric vehicle is composed of a signal detection unit, a signal comparison unit and a signal control unit. The signal detection unit is formed by four ferrite coil of a main circuit of the motor controller and may be able to detect suddenly increased current signals; the signal comparison unit is formed by a voltage comparison circuit, and a high level digital signal is outputted when the suddenly increased current is detected by the signal detection unit; and the signal control unit is formed by a CPLD or DSP digital signal comparison chip, when the high level digital signal emitted by the signal comparison unit is received, a PWM control signal of the main loop is completely blocked, so that a power electronic device IGBT or a power MOSFET of the main loop may be protected. The overcurrent protection system of a motor controller of an electric vehicle is simple in structure and short in response time, and is capable of protecting the power electronic device of the main loop of the motor controller of the electric vehicle and performing the overcurrent protection of the motor, therefore the safe operation of the electric vehicle may be ensured.

Description

technical field [0001] The invention discloses an overcurrent protection system for a motor controller of an electric vehicle, which belongs to the technical field of electric vehicle motor drive control. Background technique [0002] The motor controller of an electric vehicle converts the DC power of the on-board DC power supply (such as a battery) and the AC power required or generated by the drive motor, controls the working state of the motor, and then controls the running state of the vehicle. The digital control core chip in the motor controller generates a PWM signal to control the power electronic devices (such as IGBT or power MOSFET) in the main circuit according to the torque demand of the vehicle and based on the vector control algorithm, so as to realize DC power and AC power. Transform each other to control the output torque or running speed of the motor. [0003] During the working process of the motor controller, current overcurrent may occur due to interna...

AI Technical Summary

Problems solved by technology

The disadvantage of this detection method is that it cannot detect the short circuit on the DC side of the main circuit (such as a capacitor), and at the same time, the anti-interference ability is poor, and false detections occur from time to time, thus reducing the reliability of the system.

Another detection method is to use the Hall current sensor to detect the current of each branch in the main circuit. The disadvantage of this detection method is that the Hall sensor needs an external power supply to work, and the sensor will produce errors after working for a long time, and the cost is also high. higher

Therefore, the use of Hall sensors for current detection increases the complexity and cost of the system

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