A novel standstill position detection method of PMSM for electric vehicles based on carrier phase-shifted PWM technology

This paper presents the application of carrier phase-shifted PWM technology in the position detection for permanent magnet synchronous motor at standstill position. At the same time, it gives the polarity identification in the rotary frame with detected position from the neutral voltage. The new technique describes the method of carrier phase-shifted PWM technology with neutral voltage. It can detect the motor position from simple measurements of the neutral point voltage of the motor influenced by the variation of inductances with respect to rotor position. Theoretical studies have been carried out and experimental results are implemented to vary rotor position over one electrical cycle for position detection.