Low-Frequency Pulse Voltage Injection Scheme-Based Sensorless Control of IPMSM Drives for Audible Noise Reduction

Abstract

High-frequency (HF) signal injection has been widely used in the sensorless control of interior permanent magnet synchronous motor (IPMSM) drives for zero- and low-speed operation. However, the audible noise pollution caused by induced HF current has restricted its application. To solve this problem, a low-frequency (LF) pulse voltage injection scheme is proposed in this paper. Different from the traditional LF injection methods, by separating the injection and the control periods, it is easy to extract the fundamental and the induced currents without digital filters, which makes the position estimation more realizable. Since the accuracy of position estimation decreases, an enhanced vector-tracking observer based on the harmonic analysis of the discrete position signal is proposed. Then, the stability of the proposed observer is analyzed. The negative effects of estimation errors on position estimation are investigated, and notch filters are adopted to achieve further harmonic reduction. Finally, this sensorless control method is verified by experiments on a 2.2-kW IPMSM drive platform.