We have developed a position and speed estimation method that utilizes reactive power to enable stable operation of permanent magnet synchronous motor (PMSM) in the low-speed range. In position sensorless vector control, the synchronous drive method is typically employed at speeds below approximately one-tenth of the base frequency. By leveraging reactive power information, the proposed method exhibits low sensitivity to temperature-induced resistance variations and enables high-accuracy phase error estimation. Furthermore, the relationship between the electrical parameters of the PMSM and the axis phase error, caused by controller setting errors can be analytically clarified. The effectiveness of the proposed method is validated through mathematical analysis, time-domain simulations, and experimental results.
Tobari et al. (Sat,) studied this question.