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.