Multi-Objective Design Optimization of a Tubular Permanent Magnet Linear Generator With 120° Phase Belt Toroidal Windings

The utilization of 120 degrees phase belt toroidal windings (120 degrees-TWs) can bring power density improvement in a tubular permanent magnet linear generator (TPMLG). Unfortunately, the TPMLG with 120 degrees-TWs (120 degrees-TPMLG) usually involve multiple structural parameters, and the interaction or even conflict among those structural parameters would have strong impact on generator performances in the design optimization process. To alleviate this problem, a multi-objective design optimization method is proposed to conduct a multi-objectives optimization, which aims to obtain the high-power density and low-detent force. First, the comprehensive sensitivity analysis method, namely global sensitivity analysis, is adopted to evaluate the sensitivities of the structural parameters on the performances of the 120 degrees-TPMLG. According to the evaluation results, the structural parameters are divided into three levels: non-sensitive level, mild-sensitive level, and strong-sensitive level. Then, to improve the whole design optimization efficiency, the direct-screening method, the surface method, and the genetic algorithm is implemented in the three levels, respectively. And the optimal structural parameters of the 120 degrees-TPMLG are finally determined. To verify the feasibility of the 120 degrees-TPMLG and the effectiveness of the proposed design optimization method, the performances of the optimal 120 degrees-TPMLG are analyzed and compared with the initial one and the same dimensions TPMLG with traditional toroidal windings (T-TPMLG) in detail. It shows that the performances of the optimal 120 degrees-TPMLG meet the design requirements. Moreover, the detent force is largely decreased and the power density is notably improved. The results prove that the proposed multi-objective design optimization method is available for the 120 degrees-TPMLG.

Automated summary

This paper proposes a multi-objective design optimization method for a tubular permanent magnet linear generator (TPMLG) with 120 degrees phase belt toroidal windings (120 degrees-TWs). The method divides the structural parameters into different sensitivity levels and uses direct-screening, surface method, and genetic algorithm to optimize the generator. The optimal 120 degrees-TPMLG shows improved performance with lower detent force and higher power density.