The Realization Of Sensorless Control For Switched Reluctance Motor

Switched Reluctance Motor Drive (SRD) is a new type ac drive system of mechanical and electrical integration which is getting more and more concerns due to their simple and solid structures, low cost, high operation reliability and well speed control performance in the several decades of years. It Is one of the hot topics in the field of modern electrical drive.However, due to the existence of torque ripple, the popularization and application of SRM were subjected to severe constraints, so inhibiting the torque ripple of SRM becomes one of popular research direction. What’s more, the rotor position information which is real-time and accurate is necessary premise to the reliable operation of SRM, however, the position sensor is not only making the structure of SRM complicated, but also causes the cost rising. In addition, because of the limited sensor resolution and the sensitivity to external interference, the precision of the control and the operation reliability are both reduced, so the sensorless control for SRM has important significance. This article is mainly studied these two problems.In order to reduce the torque ripple, a switched reluctance drive system based on torque sharing function is established in this article. On the basis of choosing appropriate torque sharing function, sharing the desired torque to each phase winding according to the actual rotor position, and then ensure the implementation of phase torque through the torque loop, so as to reduce the torque ripple. System simulation has verified the effectiveness of the scheme.In order to implement the sensorless control scheme, this article uses the simplified flux method to carry on the position detection, determine the phase winding flux linkage actually according to the information such as the phase current and phase voltage, and then, determine the commutation position according to the deviation of estimated flux and reference flux, thus to achieve the sensorless scheme of SRD. In view of the above scheme is unable to determine the rotor initial position, a method is proposed in this article which injects voltage pulse into each phase winding through the bootstrap capacitor, and then obtaining the range of rotor initial position according to each phase current, so as to make the motor starting. Finally, the above-mentioned sensorless scheme of SRD is simulated and it verified that the scheme is effective.