Variable flux memory motors: A review

Variable flux memory motors (VFMMs) are a relatively new class of machine that affords one the ability to actively change a motor from a high torque/low speed device into a low torque/high speed device through the online control. With regard to the method of controlling flux, VFMMs are categorized in this paper. The different VFMMs are reviewed based on the relevant literature domestic and abroad, and their topological features, operating principles, merits and demerits are summarized and analyzed. Also the common existing problems of VFMMs are pointed out.