Indirect Position Sensing at Stand-Still and Running State in SRM by Using Distributed Voltage and Voltage Rate for Injected Pulse

To eliminate position sensor from switched reluctance motor drive, many kinds of position estimation methods have been proposed. Most of them require current or voltage sensing to compute inductance or flux linkage, and data tables concerning with these parameters and rotor position. The current sensor is generally expensive. In addition, large amount of memory is necessary to save the data tables. To overcome these problems in this paper, a simple position estimation method using a gradient of distributed phase voltage obtained from voltage injection into SRM through full bridge bipolar type inverter is proposed. However, this method has estimation error at some position. To solve this problem, also novel method using voltage rates of distributed voltage are proposed. As a result, the position estimation with high resolution in wide speed range including standstill is possible. Through experiment using 400W four-phase 8/6 test motor, the effectiveness of proposed method is demonstrated.