Design and Optimization of a New Magnetic-Geared Pole-Changing Hybrid Excitation Machine

This paper presents a new magnetic-gear pole-changing hybrid excitation machine (MG-PCHEM), which can provide high torque density and improved flux-weakening ability. The key is to flexibly change the pole-pair number of inner excitation sources by injecting variable dc field currents, and, hence, regulate the dominant pole-pair flux components to realize an effective magnetic field adjustment. In the following paper, the machine configuration and its operation principle of flux control are introduced first. Then, the influences of some leading design parameters are analyzed including the slot-pole combination and other dimension parameters, and after which a comparative study is carried out with traditional single-stator topology. Based on the optimal design, electromagnetic performance of the MG-PCHEM is further evaluated by using the finite-element method. Finally, a prototype is designed, manufactured, and fully tested. Relevant experimental results verify the feasibility of this new hybrid solution as well as the finite-element predictions.