Power Quality Improvement of Switched Reluctance Motor Drives

Abstract

The Switched Reluctance Motor (SRM) drive has evolved as an alternative to conventional motors in variable speed drives because of advantages like simple and rugged structure, absence of rotor winding, adaptability to harsh environments and high speed operation. An observer is introduced to guarantee both fast response and stability of the dead-beat current controller. The controller is tested for two different speeds at three different load torques. Steady state analysis of the drive has been carried out. The proposed digital PWM current controller has almost the same performance as hysteresis current regulation and at the same time, avoids its drawbacks. Variable switching frequency in hysteresis control makes it difficult to design the electromagnetic interference (EMI) filter and may cause acoustical noise. Even though the analog-to-digital converters (ADC) nowadays could have very high sampling rates, EMI caused by the converter would add great noise to the sampling process, which might cause fault in the operation of SRM. Current control is essential in SRM drives. Conventionally, hysteresis current regulation is utilized for current control in SRM drives, but it has some drawbacks including high sampling rate requirement, sensitivity to switching EMI noise, and varying switching frequency. In order to design a current controller with both fast dynamic response and small tracking error, more information of model of SRM is needed. With its flux linkage profile, an SRM could be well modeled and simulated by using MAT Lab/Simulink.