Sensorless Noise Reduction Strategy for Permanent Magnet Synchronous Motor Based on Random High-Frequency Sinusoidal Injection

In the sensorless permanent magnet synchronous motor (PMSM) control system, the additional noise caused by high-frequency (HF) injection method greatly affects the wide application in various fields. The noise reduction ability of the traditional HF sinusoidal injection method using the full-period-switching random HF injection method is unsatisfactory. Therefore, a novel random HF sinusoidal injection method based on half-period-switch is proposed in this paper, which switches the injection frequency once per half period to improve the overall noise reduction effect. The mechanism of noise reduction can be verified by power spectral density analysis. Finally, the effectiveness of the proposed strategy is verified on a 2.2-kW sensorless PMSM drive platform.