Fundamental PWM Excitation Based Low-Speed Sensorless Control Method for PMSM Drives

Signal injection methods have been highly applied in sensorless control system of interior permanent magnet synchronous motor (IPMSM) drives. However, there are inherent disadvantages of signal injection methods which are additional torque ripple and high frequency audible noise. In this paper, a rotor position estimation method is proposed by detecting the derivative of phase currents. The rotor estimation based on rotor saliency-tracking technology shows a good performance in the low-speed motor operation region. Compared with the signal injection method, the proposed method is more suitable for a noise-free working environment.