Multiobjective Control Strategy for Switched Reluctance Machine With Online Efficiency Estimation and Improved Online Instantaneous Torque Estimation

Torque ripple and system efficiency are two major limitations for further application of switched reluctance machines (SRMs). Due to the highly nonlinear characteristic of SRM, it is hard to estimate system efficiency and instantaneous torque with traditional analytical methods. Thus, an average torque estimator is proposed in this article and the average torque is estimated according to the energy conversion loop on the flux linkage and current plane of each stroke. For torque ripple estimation, an improved instantaneous torque estimation method is proposed, which estimates the instantaneous torque based on the fluctuation of the instantaneous rotor speed. Then, a multiobjective control method consisting of a rotor speed controller and a multiobjective optimizer is proposed for multiobjective control. In the proposed multiobjective control strategy, the motor control is divided into two steps. First, the rotor speed control is set as the top priority, which ensures the rotor speed response. Then, a multiobjective controller that considers both system efficiency and torque ripple will be activated to improve the overall performance according to the online multiobjective evaluation result. In the end, to verify the effectiveness of the proposed method, simulation and experimental results are performed under different operating conditions.