Exact Modeling and Multi-Objective Optimization of Vernier Machines

This paper presents a high-fidelity analytical solution and a fast integrated optimization method for vernier machines. Firstly, a harmonic modeling method (HMM) is adopted to obtain the magnetic field distribution of vernier machines. Particularly, the stator teeth of vernier machines are divided into several blocks to take account of the local magnetic saturation of soft-magnetic material. Then, the electromagnetic parameters, such as the average torque, torque ripple and efficiency, can be calculated via the analytical model. Next, the proposed harmonic model is combined with the non-dominated sorting genetic algorithm II (NSGA-II) to determine a multi-objective optimal design for the studied vernier machine. This integrated optimization method can save computation time, because the data interaction process between the finite element analysis (FEA) software and the optimization software is eliminated. Finally, the performances of the optimal case are verified by both FEA and experiments with the prototype.