9. Analysis and Test Research for Three-Phase Short-Circuit of Permanent Magnet Synchronous Motor for an Electric Vehicle

Permanent magnet synchronous motor (PMSM) is widely used in the electric vehicle as a drive motor. For specific application requirements of the electric vehicle motor system, there are new faults and application characteristics in motor system’s three-phase short-circuit. Based on the \( dq \) axis coordinate system mathematical model of PMSM, this paper derives the \( dq \) axis current transient equations of three-phase transient short-circuit with load or without load in initial state. Combined electric vehicle PMSM operating characteristics, based on the typical working conditions, this paper analyzes the influences of motor demagnetization risk in different conditions by comparing the transient current changing process simulation results of different initial transient \( dq \) axis currents. Then according to the characteristics of the three-phase transient short-circuit, designs and builds a test platform, and verifies the correctness of the analysis and mathematical simulation models by testing. It provides an important theoretical analysis and test verification methods for analyzing the electric vehicle PMSM three-phase short-current function and determining the risk of demagnetization.