Torque Ripple Suppression Technique of High-Frequency Signal Injection Sensorless Control

The high-frequency (HF) signal injection-based sensorless control injects the voltage signal and estimates the rotor position from the induced HF current. However, the induced HF current causes an HF torque, resulting in torque ripples and acoustic noise. To mitigate these disadvantages, this paper proposes a torque ripple suppression technique of an HF signal injection-based sensorless control. The signal injection angle minimizing the HF torque is found with the proposed HF torque ripple regulator based on the analysis of the HF torque from the induced HF current. The HF torque and acoustic noise can be minimized if the proposed method injects the voltage signal into the determined angle. The proposed method was verified through experiments using an 11 kW IPMSM, and the results proved that HF torque could be minimized with the proposed method.