Operating Performance Enhancing Method for Doubly Salient Electromagnetic Machine Under Light Load Condition

Nowadays, more and more electric machines are demanded to operate under wide ranges of speed and load conditions. This paper deals with the operating performance enhancing method for doubly salient electromagnetic machine (DSEM) under light load condition. With the finding that the power loss can be decreased with reduced field current, and there's regulated space for the distribution of field current and armature current under light load condition. A novel control method with field current inner loop and speed outer loop is proposed for DSEM, the system driving efficiency is desired to be improved. Meanwhile, the cogging torque which is a main ripple source of DSEM torque can be decreased with the reduced filed current, so the output torque performance can be enhanced as well. In addition, the armature reaction of the proposed control method is researched, and the influence on the filed current control during commutation process is theoretically analyzed. The experiments on a 12/8-pole DSEM validate the correctness and flexibility of the proposed control method.