High-Frequency Harmonic Suppression Strategy and Modified Notch Filter-Based Active Damping for Low-Inductance HPMSM

The voltage inverters have the high-frequency switching characteristic, which will generate massive high-frequency harmonics in the motors. Especially, the inductance of the high-speed permanent magnet synchronous motor (HPMSM) is designed to be small, and the high-frequency harmonic content will be higher than that of ordinary motors, which adversely affects the system. To overcome this problem, this paper proposed a harmonic suppression method based on the LC filter and the adaptive notch filter for HPMSMs. The LC filter is connected between the inverter and the HPMSM to filter out high-frequency harmonics, however, at the cost of the system resonance. Therefore, the adaptive notch filter with the frequency tracking capability is designed to offset specific resonant peaks by constructing an antiresonant peak. The least mean square adaptive algorithm automatically adjusts the filter parameters according to the variation of the input signal to ensure accurate filtering in complex cases. Simulation and experiment results prove the practicability and effectiveness of the proposed scheme. The harmonic contents of HPMSM are significantly reduced, and the dynamic response performance of the control system is improved.