Improvement of sensorless speed control for nonsalient type axial gap self-bearing motor using sliding mode observer

This paper presents an improvement of sensorless speed vector control for a nonsalient type axial gap self bearing motor (AGBM), in which rotor speed and position are estimated by using sliding mode observer with full mathematical model. The approach is based on the estimation of the motor back-EMF (or induced voltage) through a sliding mode observer with help of reference voltages, measured stator currents and measured displacement. In order to achieve an accurate estimation of the rotor speed and position, an adaptive gain of the sliding mode controller is proposed. Experiment was implemented based on dSpace1104 with two three phase inverters. Results confirm that the sensorless drive for AGBM achieved at the average and high speed range, so further work is being continued to improve the experiment for this proposal at low speed range.