Research on control strategies for doubly salient electromagnetic machine

Abstract

The doubly salient electromagnetic machine (DSEM) is a kind of variable reluctance machine, which is different from the conventional AC electric machines. The standard angle control and the three-state angle-advanced control are traditional control strategies for DSEM, with dead zone existing. Six-SAA (SSAA) control is a newly proposed control strategy with no dead zone. Compared to traditional control strategies, it can increase output torque, and reduce the torque ripple. However, it is hard to select proper advanced angles in SSAA control. In this study, a 12/8-pole DSEM has been studied. Then, several control strategies for DSEM are presented, and the operating principles are analysed in detail. After that, a new control strategy is proposed, and its characteristic during commutation stage is analysed. Besides, the optimal advanced angles are deduced, with its variation characteristics, and the comparison of these control strategies are conducted by finite element simulation. With the proposed control strategy, a higher-output torque can be acquired in a wide-speed range, and meanwhile, the selection of advanced angles is simplified. Finally, the theoretical analysis is verified by simulations and experimental results.