A novel dual-structure parallel hybrid excitation machine for electric vehicle propulsion

Magnetic field regulation is a difficult and long-existing issue in surface-mounted permanent magnet synchronous machines (PMSMs). To produce effective and efficient flux regulation for PMSMs, a new topology, named a dual-structure parallel hybrid excitation machine (DS-PHEM), is presented in this paper. In this machine, the rotating permanent magnet (PM) excitation and stationary DC field excitation are artificially arranged and designed at the inner and outer magnetic circuits, respectively. Therefore, a decoupling and parallel feature is obtained between two excitation sources. This machine integrates the merits of a brushless structure and theoretically infinite constant power range, as well as zero risk of demagnetization. In this paper, the machine configuration is introduced, mainly focusing on some important design criteria for electromagnetic integration, and the operating principles of flux control are also analyzed in detail. To further verify the feasibility of the proposed scheme, the overall electromagnetic performance of the proposed DS-PHEM is evaluated by using the time-stepping finite-element method.