Limitations/capabilities of electric machine technologies and modeling approaches for electric motor design and analysis in plug-in electric vehicle applications

The electrical machine (EM) is a key component in plug-in electric and hybrid vehicle (PEV) propulsion systems. It must be designed for high torque/power densities, wide speed range, over load capability, high efficiency at all speeds, low cost and weight, fast acceleration and deceleration, while meeting performance and reliability expectations. This paper overviews various EM technologies that are the best candidates for use in PEVs. Their basic operational characteristics, design features and relative advantages and disadvantages are discussed and compared for PEV propulsion systems. The latest and future research directions of EMs for PEVs are identified and discussed. Literature concerned with limitations and capabilities of finite element analysis and magnetic equivalent circuit analysis for EM design and analysis in PEVs is presented. Unfortunately, few papers give thorough comparisons between experimental measurements and simulation tools for EMs; even fewer compare torque. Those that report on torque show errors of 10% or more between tests and simulations. Saturation and losses appear to be the likely culprits. When nonlinear magnetic effects are taken into account, including magnetic saturation, eddy currents losses, and modeled with care, differences between simulations and tests typically are on the order of 5%.