A Position Sensorless Speed Control for Switched Reluctance Motor at Low Speeds

This paper describes a position sensorless speed control for switched reluctance motors (SRMs) at low speeds. The sensorless drive can be carried out using the phase inductance in the phase previously turned off. This unenergized phase inductance is computed by applying the voltage pulses in a short time. The turn-off timing is decided so that the regenerative current becomes zero when the rotor and stator poles are aligned. At standstill, the phase excited initially is determined based on the profiles of the phase inductance in order to move the rotor toward the desired direction. The experimental results show that the SRM is well controlled from standstill.