A Position Estimation Method Based on Modified Integrator of PMSM Sensorless Control for High-Speed Vehicles

In the high-speed traction permanent magnet synchronous motor (PMSM) drive system, control methods without position and speed sensors are adopted because of occupying smaller space, lower cost, higher reliability and less sensitivity to the environment which is more suitable for motors using in traction vehicles. According to the stator voltage and measured current, the stator flux is integrating from the difference value of the voltage, where back-EMF can be calculated and rotor position can be estimated. Based on the estimating method of integrating back-EMF, this paper proposes a modified integrator to solve the problems produced by the pure integrator, which brings up DC offset to estimating motor flux. Simulation and experiment results show that this integrator can accurately estimate both the magnitude and the phase angle of the motor flux, including the speed of PMSM. Besides, the perfomance of the integrator shows that it has good dynamic and steady characteristics.