A sensorless wide-speed range SRM drive with optimally designed critical rotor angles

A switched reluctance motor (SRM) drive optimized to achieve sensorless operation over wide-speed range with lowered torque-ripple is presented in this paper. Wide-speed range is obtained by phase advancing between two extreme critical rotor angles; lowered torque-ripple is obtained by effective torque sharing of adjacent phases; and sensorless operation is achieved through a sliding-mode observer (SMO) based algorithm. The research reveals the method of determination of critical rotor angles from machine geometry and material properties and suggests the design considerations to optimize the control parameters. The research also defines the phase advancing strategy between the critical rotor angles and the torque sharing mechanism by introducing a natural commutation period. The integrated SRM drive with simulation and experimental results using TMS320C30 DSP are presented for verification