Investigation of Design Methods to Improve the Performance of a Motor Which is Capable of Switching Between WFFSM Drive and SynRM Drive

In a previous study, a motor capable of switching between WFFSM drive and SynRM drive is proposed. However, the WFFSM is designed primarily to maximize torque at low speeds. Consequently, there is a region where efficiency drastically deteriorates in the high speed, low torque region of WFFSM operation, while the torque in the high-speed region of SynRM operation decreases significantly. This paper conducts various design studies to explore methods for addressing these issues. It is found that excessive magnetic saturation should be avoided to improve efficiency. However, it is also necessary to actively utilize the magnetic saturation region, as the structure required to achieve the switching function complicates torque production. This indicates a trade-off relationship between efficiency and operating range. In practice, it is found that the target output is not significantly achieved when constraints aimed at improving efficiency are implemented.