Computationally Efficient Analytical Model of Permanent Magnet Vernier Machines

Subdomain model is known to be the most accurate analytical solution for predicting the electromagnetic performance of Permanent Magnet (PM) machines. However, the solution could get computationally costly particularly in asymmetrical structures with high slot and pole number, such as fractional slot PM Vernier machines. This paper presents a hybrid analytical model based on a "2-D subdomain" model in conjunction with the "flux function" model to decrease the number of subdomain regions, and thereby the overall computation. For this purpose, stator slots and Flux Modulation Pole (FMP) slots are nullified (to limit the subdomain regions into PMs and airgap) and the subdomain model is applied only to predict the airgap flux distribution in a slot-less machine. Next, the stator slotting and FMP slotting effects are accounted via the flux function method. To determine the precision of the presented model a comparative open-circuit analysis is carried out against the 2-D subdomain model, 1-D magnetic circuit model and Finite Element (FE) model.