Optimal design procedure of a high-torque-density dual-stator consequent-pole Vernier PM machine

Abstract

It can be concluded from the results of the previously published studies that the dual-stator consequent-pole Vernier PM machine introduces several advantages including higher torque per PM volume density, lower cogging torque, improved efficiency and simpler and more robust structure in comparison with the other presented structures. However, the optimal design procedure of the machine is not established yet. The importance of this issue is because of different geometry than conventional radial flux machines, unbalanced magnetic forces and mechanical and thermal limitations. In this paper, design variables are selected based on sensitivity analyses using FE method. Then, the objective function is defined as maximizing torque, efficiency and power factor and minimizing cogging torque. Several design constrained are imposed on the geometry dimensions, current densities and magnetic flux densities in different regions and mechanical forces. Magnetic equivalent circuit model is implemented for predicting the machine performance by varying the design parameters in each iteration of population-based optimization algorithm. The results of an optimum designed 10 kW machine with 2 kNm torque for in-wheel electric vehicle application are verified using 3D FE method.