Sensorless control of the fault-tolerant permanent magnet motor based on sliding mode observer

The fault-tolerant permanent magnet motor (FTPMM) drive can overcome the shortcomings of SRM and PMSM and has good fault-tolerant capacity. On the base of analyzing the structure and mathematical model of FTPMM, the sensorless control strategy was proposed. The basic equation of an improved sliding mode observer (SMO) was constructed according to the differences between the observed current and the actual current. Combined with model reference adaptive method to confirm the switch gain of sliding surface, the rotor position and rotor speed were estimated accurately. By replacing the sign function with the sigmoid function, the system chattering was also reduced. Finally, the correctness of the proposed algorithm based on sliding mode observer was verified by computer simulation.