Optimized doubly salient memory motors with symmetric features using transposition design methods

In order to solve the problems caused by the asymmetry among phases due to their different relative positions to magnets in the conventional doubly salient permanent magnet motors, two transposition design methods are proposed in this paper, and then employed to the design of doubly salient memory motors which incorporates the concept of the memory motor into the hybrid field excitation doubly salient permanent magnet motor structure. A comparative study between the proposed and conventional doubly salient memory motors is conducted. It is shown that the proposed new design methods can essentially solve the asymmetric problem among phases and also achieve other salient features such as more flexible choices of rotor teeth, smaller torque ripple and optimized back electromotive force and armature current waveforms. Finally, a prototype is built and experimentally verified the validity of the proposed design method.