Analytical model of Dual PM Vernier Machines based on Differential Magnetic Circuit

This paper introduces an enhanced analytical model for the dual PM vernier machine (DPVM), which can achieve higher torque density than regular PM machines by utilizing multiple torque components. The model is based on a differential magnetic circuit (DMC) airgap radial flux density (ARFD) analytical method that considers the multiple sources of excited MMF on both rotor and stator sides. Initially, the slotless ARFD of the consequent pole magnet (CPM) is derived using the DMC method, and subsequently, the slotted ARFD is obtained and validated by 2D FEA results. The deviation of salient pole ARFD due to the rise of magnetic potential is also analyzed, and a corrected equation is presented. Equations for the no-load back EMF and average torque of DPVMs are then derived based on the working ARFD. The influence of flux saturation on the torque performance of DPVM is discussed through simulations of DPVMs with different core materials. Finally, the analytical performances of DPVMs under varied parameters are presented and compared with FEA results, demonstrating the potential application of the proposed analytical method in the initial parameter design of DPVMs.