A novel sensorless technique for a new field assisted switched reluctance motor

Rotor position sensing is an essential part of switched reluctance (SR) motor drive in order to synchronize the pulses of phase current with the period of rising inductance of the proper motor phase. This paper presents a complete and novel method to detect the rotor position at standstill and also low speeds in a new field assisted switched reluctance motor. In this method, a high frequency sine wave signal is applied to the field winding and then the magnitude of induced signals on each phase winding is monitored to detect the rotor position at standstill. It then continues to sense the rotor position while the motor is running at low speed by utilizing the same sine wave signal to the field winding but this time the envelope of induced voltages on the un-energized phase windings are measured and compared. The experimental results obtained demonstrate the feasibility and practicability of the method.