Electric Machine Design Approaches for Electrified Powertrains

Electric machines used in electrified powertrains are required to have high torque density, low energy loss over driving cycles, wide constant-power speed-range, and produce low vibration and audible noise and most importantly be low cost. These requirements are intrinsically in conflict with each other and therefore it is challenging to develop machine designs that yield optimum trade-offs. New design concepts and approaches together with optimization techniques and CAE tools are needed to develop electric machine designs that meet these challenging requirements. The paper discusses the unique aspects of the requirements for electric machines used in electrified powertrains and the challenges of meeting them. Examples of newly developed concepts are presented to illustrate how to resolve some of the challenging design issues. Design optimization using genetic algorithms and high performance computing strategy are discussed and examples of coupled electromagnetic and mechanical design optimization are given.