The existing rotor initial position detection for sensorless permanent magnet synchronous motor （PMSM） has some common issues such as the multiple signal injection, complicated process and dependency on the parameters. To deal with these problems, a novel method based on the current envelope was proposed. The high frequency fluctuating voltage signal was injected into the estimated two-phase coordinate system only once, which rotated at low frequency. The positive direction of permanent magnet was obtained by extracting the reference value of the coordinate system, which corresponded to the maximum value of d-axis current positive envelope. Furthermore, the rotor position was determined after the position compensation. On the basis of previous process, the reference value of the coordinate system was extracted, which corresponded to the minimum value of q-axis current positive envelope, then the more accurate rotor initial position was obtained after a rotor position correction. In addition, the effect of the injected voltage signal on the presented method was analyzed. With a maximum error of 4.1° and an average error of 1.8°, the experimental results show that the proposed method is simple and feasible.
Proceedings of the CSEE
permanent magnet synchronous motor （PMSM）
rotor initial position detection
high frequency voltage signal