Position and velocity control of sensorless synchronous reluctance motor using disturbance observer based on high frequency current

Synchronous reluctance motors (SynRMs) are studied because of sturdiness, and sensorless control of SynRMs is desired. Several methods have been proposed and in their methods, the flux generated by the current is estimated and the position is estimated from the flux. Therefore, it is necessary that the currents unrelated to the torque flow at light load. At low speed, the voltages for estimation of flux are small. The stability of estimation is not guaranteed. In this paper, a new position estimation method is proposed using the disturbance observer based on high frequency currents. It is possible to estimate the position without the currents which do not generate torque at low speeds and at light loads using high frequency currents. The stability of estimation is guaranteed by a disturbance observer using high frequency voltages and currents. The simulation results show that the proposed method is very useful.