Magnetic Coupler Robust Optimization Design for Electric Vehicle Wireless Charger Based on Improved Simulated Annealing Algorithm

Zhenpo Wang,Shuo Wang,Baokun Zhang,Junjun Deng,Lantian Li

doi:10.1007/s42154-021-00167-9

Abstract

Fleets of autonomous vehicles including shuttle buses, freight trucks, and road sweepers will be deployed in the Olympic Village during Beijing 2022 Winter Olympics. This requires intelligent charging infrastructure based on wireless power transfer technology to be equipped. To increase the misalignment tolerance of a high-power wireless charger, the robustness of the magnetic coupler should be optimized. This paper presents a new type of unipolar coupler, which is composed of three connected coils in series. The dimensional configuration of the coils is analyzed by the finite element method. The characteristic parameters of the coil are identified with their influence on the self-inductance and coupling coefficient. An expert model is built, whose feasibility can be verified in the aimed design domain. Combined with the expert model, an improved simulated annealing algorithm with a backtracking mechanism is proposed. The primary coil can reach the expected characteristics from any starting parameter combination through the proposed optimization algorithm. Under the same conditions in terms of external circuit parameters, ferrite usage, and aluminum shielding, the offset sensitivity of the magnetic coupler can be reduced from 58.79% to 18.89%. A prototype is established, validating the feasibility of the proposed coil structure with the optimized parameter algorithm.

Highlights

The application of wireless power transfer (WPT) technology in electric vehicles, especially the inductive power transfer (IPT) technology, effectively reduces manual interventions, making the charging process safer, more efficient and convenient
Based on the analysis of the influence of multiple series unipolar coil (MS coil) mechanical dimension changes on electrical parameters, this paper proposes an expert model for MS coil parameter optimization, which can approach the targeted mutual inductance and self-inductance
Through comparative analysis by finite element analysis (FEA), an expert model is built while an improved simulated annealing (SA) algorithm is proposed

Summary

Introduction

The application of wireless power transfer (WPT) technology in electric vehicles, especially the inductive power transfer (IPT) technology, effectively reduces manual interventions, making the charging process safer, more efficient and convenient. Electric commercial vehicles have higher chassis and heavy weight, which call for higher charging power while facing lower parking position accuracy. In high-power IPT systems for electric vehicles, the limited onboard space is the main design constraint. For many high-power electric vehicle wireless charging systems, the simplest series-series (S-S) compensation topology is more suitable [8]. The degree of freedom of parameter adjustment of the compensation circuit is limited and the performance of the system is affected by the variation of the coupling coefficient, which is inevitable due to parking deviation. To improve the robustness of the highpower IPT system, it is necessary to optimize the design of the unipolar coil according to the characteristics of the S-S topology.

Selection Basis of MS Coil

Expert Model for MS Coil Optimization

Improved SA Algorithm

Conclusions

Findings

National highway traffic safety administration