Advance Topic: Sensorless Control of Switched Reluctance Motor

The modulation method was used in [10] and [11]. The phase inductance of non-conducting phase is extracted in an encoded form using a modulator consisting of electronic circuitry. The signal is then decoded to obtain the inductance from which the rotor position is determined. Various modulation techniques are available to extract the phase inductance and they are frequency (FM), phase (PM) and amplitude modulations (AM). The FM encoder technique is to generate a square wave whose frequency is proportional to the inductance of a phase. The PM and AM techniques are based on the phase and amplitude variations of the phase current due to the varying phase inductance, when a sinusoidal voltage is applied to the phase winding with an external resistance in series.