A Novel Control Method of Improved Flux-Weakening Trajectory for IPMSM

In order to solve the problem that the interior permanent magnet synchronous motor (IPMSM) for electric vehicles may be irreversibly demagnetized at high temperature and high speed, the method of checking the maximal demagnetizing current of permanent magnet (PM) is introduced, and a novel control method of improved flux-weakening trajectory considering the demagnetization of PM is put forward. Furthermore, a traditional flux-weakening control method based on voltage feedback is introduced in this paper. To verify and compare the two flux-weakening methods based on current vector control system, the control system simulation model for IPMSM is developed. The simulation results clarify that both two flux-weakening methods extend the constant power region of PMSM effectively, while the method of the improved flux-weakening trajectory can ensures the safe operation of the motors within the current limit range under the specified working conditions and improves the safety performance of the motors.