Phase Current Measurement Method for Switched Reluctance Motors With One Current Sensor

Accurate phase currents are necessary for the control and protection of motor drives. In this article, a novel phase current reconstruction strategy for switched reluctance motors (SRMs) with single current sensor is proposed. Firstly, the characteristic of the unsaturated phase inductance is analyzed. Secondly, the location of the single current sensor is rearranged, and all phase currents flow through the sensor in positive direction. The phase current in unsaturated region is directly obtained by dividing the flux linkage by the unsaturated inductance. In the linear region, the phase current is calculated by solving the similar triangles according to the relationship between the unsaturated inductance and saturated inductance. Finally, the overall control strategies of SRM drive integrated with the proposed phase current reconstruction method are implemented. The proposed method can be used for different chopping modes and different control strategies. Simulations and experiments on a three-phase 12/8 SRM validate the effectiveness of the proposed phase current reconstruction scheme.