Novel encoder for SRM drive with high resolution angle control

In a switched reluctance motor drive, it is important to synchronize the stator phase excitation with the rotor position; therefore, the information about rotor position is essential. Although optical encoders or resolvers are used to provide the position information, these sensors are expensive. Moreover, in the high-speed region, switching angles are fluctuated back and forth out of the preset value, which is caused by the sampling period of the microprocessor. In this paper, a low cost linear encoder suitable for the practical and stable SRM drive is proposed and also the control algorithm to generate switching signals using a simple digital logic is presented. The validity of the proposed linear encoder with a proper logic controller is verified from the experiments.