Sensorless Control of Switched Reluctance Motor Based on Phase Inductance Vectors

A new sensorless control method based on phase inductance vectors of switched reluctance motor (SRM) is presented in this paper. To implement this method, the following was done. First, based on the pulse injection technique, a new method called phase current slope difference is proposed for identifying the full-cycle phase inductance of each phase. Second, the phase inductances are considered as vectors with fixed phase difference and the composed vector is rotated with the varied rotor position. Combining the composed vector orthogonal decomposition method and a new inductance subregional method, the rotor position can be estimated. This method can realize sensorless control of SRM from starting up at standstill to high-speed operation and is quite easy to implement. No additional hardware or complex computation is required and no a priori knowledge on magnetic characteristics of SRM is necessary. To verify the performance of the proposed sensorless scheme, the following experiments have been performed: 1) the initial rotor position at standstill and rotating shaft conditions are estimated for sensorless startup control; and 2) the rotor position and rotational speed are estimated at different reference speeds for sensorless speed closed-loop control and the dynamic performance is fully validated.