Rotor position detection using modified amplitude modulation (AM) in SRM drives

In this paper a modified amplitude modulation (AM) technique for the assessment of rotor position in switched reluctance motor (SRM) drive is being presented. In this method, high frequency diagnostic sine wave is applied to the three stator pole windings and then the resulting magnitude of produced sine wave current for each phase is measured at standstill. The resulting current magnitude is different for each phase due to its inductance which is proportional to the rotor position. It then continues to sense the rotor position while the motor is running by applying the same signal to the un- energized phase winding and sensing the rotor position from the resulting current signal. The results obtained demonstrate the feasibility and practicability of the method.