Research on Methods of the Generation Conduction and Suppression of Shaft Voltage of Vehicle Drive Motor
[Purposes]In view of the electric corrosion problem of motor bearings due to shaft voltage after long-term operation of vehicle drive motors,analyze the generation mechanism of drive motor shaft voltage and this paper analyzes corresponding suppression methods to improve the reliability of vehicle drive motor design.[Methods]By using Matlab to establish the control model of the PMSM motor and the bearing oil film breakdown model,and combined with the electromagnetic simulation software to calculate the parasitic capacitance of the motor,this paper analyzes therelationship between shaft voltage and controller bus voltage,switching frequency,common mode voltage,torque,etc.[Findings]It is verified that the frequency of the shaft voltage is the same as the switching frequency of the controller.There is a mirror image relationship between the shaft voltage and the common mode voltage of the controller in the waveform,and the amplitude is about 3%of the common mode voltage amplitude,the correlation between the shaft voltage and the motor torque is low.[Conclusions]This model can be used to conveniently study the shaft voltage under various working conditions of the motor.According to the proposed suppression method,measures can be taken to reduce the shaft voltage in the early stage of the development of the electric drive system.
bearing electrical corrosionpermanent magnet synchronous motorshaft voltagecommon mode voltage
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