Lowcost control of switched reluctance motor using single current sampling resistance

In the split-phase converter of four phase switched reluctance motor (SRM), the number of the current sampling resistances for control can be simplified to two. However, one of that two resistances is not connected to the common ground of the controller and an additional isolation hardware circuit is needed. It results in increases in the volume and cost of the motor controller, which would make the SRM drive system less competitive in the market. Therefore, a lowcost control using single current sampling resistance for four phase SRM is proposed in this paper. The only resistance is put to connect the joint point of the two under switch devices and the power source' negative pole in the split-phase converter. By detecting the voltage on the sampling resistance, the current of each phase can be derived and the SRM can be driven reliably. Besides, considering the commutation of phase currents cannot be finished instantly, the current bulges of phase A and C are researched. Finally, the experiments upon a four phase 24/18 SRM used in electric bicycle is presented to verify the effectiveness of the proposed lowcost single current sampling resistance control.