Sensorless speed control of a permanent magnet type axial gap self-bearing motor using sliding mode observer

This paper presents an analytical and experimental evaluation of sensorless speed vector control of an axial gap self bearing motor, in which rotor speed and position are estimated by using Sliding mode observer. The approach is based on the estimation of the motor back-EMF (or induced voltage) through a sliding mode observer with help of measured stator currents and reference voltages. In order to achieve an accurate estimation of the rotor speed and position, an adaptive gain of sliding mode controller is proposed. In addition, during the operation of system, low pass filters are used to smooth the estimated variables. Experiment is implemented based on dSpace1104 with two three phase inverters. Results confirm that axial force and rotating torque can be controlled independently and motor can get the good performance in steady state at the average and high speed range, so further work is being continued to improve the experiment for this proposal.