Design and Multiobjective Optimization of a New Flux-Concentrating Rotor Combining Halbach PM Array and Spoke-Type IPM Machine

Abstract

In this article, a new spoke-type interior permanent magnet (PM) with a flux-concentrating rotor is proposed. Based on the flux-concentrating principle, the fitting parameters between PMs and magnetic cores on the rotor make a significant impact on the flux concentration and saliency effect, thus resulting in the output torque and power capacity. Therefore, taking the average torque, cogging torque, peak power, and PM utilization as the optimization objectives, first, the sensitivity analysis is carried out that includes the different geometric variables of the rotor. Afterward, the response surface model based on the Box–Behnken method is established by selecting the reasonable optimization variables. Then, the optimal solution of the design parameters is verified by solving the response surface model. Meanwhile, a set of Pareto solutions is generated by adopting a multiobjective genetic algorithm. By two-dimensional finite-element analysis, the electromagnetic performance of a 72-slot/16-pole topology with the optimized flux-concentrating rotor is analyzed and compared with that of the initial design model. The results are demonstrated based on the response surface model. The effectiveness of the multiobjective optimization design method and multiobjective genetic algorithm is confirmed for the flux-concentrating rotor. Finally, a 30-kW prototype is developed and experimented with to verify the finite-element analysis results as well as the effectiveness of multiobjective optimization.