Signal Injection Sensorless Control with Separated Signal Injection and Control Angles Exploiting an Angle Compensation

The high-frequency (HF) signal injection sensorless control (SISC) injects an HF voltage signal and estimates the rotor position from the induced HF current based on the saliency. This paper analyzes the position estimation error of SISC with tilted voltage injection. Note that the angle from the state filter converges to a certain value, not the rotor position, named as convergence angle, which is introduced in this paper. The proposed method injects an HF signal in the convergence angle, and the current control is performed in the estimated coordinates, where the estimated angle is determined according to the convergence angle and the position error based on the analysis. Since the angle compensation is exploited, the proposed method does not require significant engineering effort to determine the signal injection angle or the compensation value. Experimental results on an 11 kW IPMSM for a general-purpose drive proved the effectiveness of the proposed method.