A Novel Hybrid-Magnetic-Circuit Memory Machine With Variable-Leakage-Flux Capability

Hybrid magnetic circuit memory machine (HMC-MM) integrates the advantages of parallel and series magnetic circuits. However, when used for wide-speed applications, e.g., electric vehicles, its flux regulation (FR) range still needs to be expanded. In response to this issue, this article proposes a novel variable leakage flux (VLF) HMC-MM (V+HMC-MM), which innovatively introduces the VLF design concept into MM. The proposed machine features that it can not only adjust the FR range by changing the magnetization state of the employed low coercive force permanent magnet but also further broaden the FR range by integrating the VLF design. First, the evolution of conventional HMC-MM rotor to V+HMC-MM rotor is illustrated, followed by a detailed description of their FR principle. The mechanisms that the V+HMC-MM can further improve the FR capability and maintain the excellent antiload demagnetization capability and high torque density are revealed by using equivalent magnetic circuit and graphic methods. The main electromagnetic characteristics of the V+HMC-MM are analyzed and compared with those of the conventional HMC-MM by using finite element (FE) method. Finally, a V+HMC-MM prototype is manufactured, and the correctness of the FE analysis and the superiority of the proposed structure are verified through the measurement on the prototype.