A method for active discharge control of motor windings based on DC voltage feedback control

Abstract

The present invention relates to a motor winding active discharge control method based on DC voltage feedback control, specifically comprising the following steps: Step S1: The controller receives a discharge signal, enters a current control mode, and detects the DC bus voltage. If the DC bus voltage is less than For the safety threshold of the controller, go to step S4, otherwise go to step S2; step S2: generate the triangular wave time-domain signal value through the timer, obtain the discharge time parameter and excitation current modulation amplitude, and convert the triangular wave time-domain signal value, discharge parameter Multiplying the excitation current modulation amplitude to obtain the excitation effective current; Step S3: According to the excitation effective current, generate a corresponding excitation current command and input it to the controller, and the controller discharges the high-voltage DC capacitor according to the excitation current command, and then go to step S1; Step S4: The controller exits the current control mode. Compared with the prior art, the present invention has the advantages of reducing the risk of voltage jump, improving the safety of electric vehicles and the like.

Description

technical field [0001] The invention relates to the technical field of rapid discharge of high-voltage capacitors of electric vehicles, in particular to a method for active discharge control of motor windings based on DC voltage feedback control. Background technique [0002] According to the safety requirements of electric vehicles in functional safety, fault protection and electric shock protection, after the collision of the entire electric vehicle, the on-board motor controller should reduce the high-voltage DC capacitor voltage to below the safe voltage range of 60v within 3s. Because the passive discharge method cannot achieve such a fast discharge speed, the current on-board motor controllers all have an active discharge function. After the electric vehicle is disconnected from the power supply or a collision occurs, the system will quickly reduce the DC bus voltage to below 60v. There are two ways to realize the active discharge function. The first type is to dischar...

AI Technical Summary

Problems solved by technology

The problem with the step input is that due to the small error of the zero angle, a small torque is caused, and the current is a constant DC during the process of stopping and powering off, which is not good for the heat dissipation of the device

Problems with square wave input, such as figure 1 As shown, due to the rapid change of the current command, the voltage on the capacitor fluctuates violently, and there are jumps and rises, even jumping from a safe voltage below 60v to more than 60v. This voltage response is not ideal and dangerous.

[0004] The prior art discloses a method for rapid discharge of a high-voltage capacitor of an electric vehicle motor controller. When the terminal voltage of the capacitor is greater than the safe voltage, the stator winding of the permanent magnet synchronous motor is used for rapid discharge. When the voltage jump exceeds the safe voltage threshold, the risk factor is large

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