Motor winding active discharge control method based on direct-current voltage feedback control

Abstract

The invention relates to a motor winding active discharge control method based on direct-current voltage feedback control. The method specifically comprises the following steps that S1, receiving a discharge signal by a controller, entering into a current control mode and detecting the voltage of a direct-current bus, if the voltage of the direct-current bus is smaller than a safety threshold value of the controller, executing step S4 , and otherwise, executing step S2; S2, generating a triangular wave time domain signal value through a timer, obtaining a discharge time parameter and an exciting current modulation amplitude, and multiplying the triangular wave time domain signal value, the discharge parameter and an exciting current modulation amplitude to obtain an exciting effective current; S3, generating a corresponding exciting current instruction according to the effective exciting current, inputting the exciting current instruction into the controller, discharging a high-voltagedirect-current capacitor by the controller according to the exciting current instruction, and turning to the step S1; and S4, quitting the current control mode of the controller. Compared with the prior art, the method has the advantages of reducing the danger of voltage jump, improving the driving 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 for electric vehicles, in particular to an active discharge control method for motor windings based on DC voltage feedback control. Background technique [0002] According to the safety requirements of electric vehicles in terms of functional safety, fault protection, and electric shock protection, after an electric vehicle crashes, the on-board motor controller should reduce the voltage of the high-voltage DC capacitor 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 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 discharge th...

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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