Electromagnetic Performance Analysis of a New Hybrid Excitation Synchronous Machine for Electric Vehicle Applications

In this paper, a new hybrid excitation synchronous machine (HESM) with dual-end built-in field windings is designed for electric vehicle traction applications with consideration of electromagnetic performance. This HESM topology inherits the features of brushless HESMs with magnetic shunting rotor and benefits from better space utilization. The fundamental structure and operating principle of the HESM are introduced in detail. The electromagnetic performance of the HESM, including back-electromotive force waveform, cogging torque, torque ripple, no-load flux regulation capability, and output torque capability, is analyzed by the 3-D finite-element method. The predicted results reveal that the output torque ripple of the HESM can be optimized by the coordinated operation between field current and armature current. A 100 kW prototype HESM has been designed and manufactured for experimental verification. The advantages and feasibility of the HESM in EV traction applications are validated by the test results.