A low cost position sensing method of switched reluctance motor using reflective type photo-sensors

Normally the position of the rotor is measured with absolute-encoder, resolvers and the incremental encoder. Then, the information of the rotor´s position is used to drive the SRM. However, for a simple driving system that doesn´t require precise control, it is not advisable to use expensive encoders and highly efficient microprocessors. In this paper, we introduce an economic method by replacing the conventional opto-interrupter and slotted-disk to only the reflective type photo-sensors, which removes not only a slotted disk section but drives three-phase 6/4 pole SRM forward and reverse. Also, only common analog devices are used for the control circuit, making the process more economical.