Quantitative comparison of electromagnetic performance of electrical machines for HEVs/EVs

In this paper, various types of sinusoidal-fed electrical machines, i.e. induction machines (IMs), permanent magnet (PM) machines, synchronous reluctance machines, variable flux machines, wound field machines, are comprehensively reviewed in terms of basic features, merits and demerits, and compared for HEV/EV traction applications. Their latest developments are highlighted while their electromagnetic performance are quantitatively compared based on the same specification as the Prius 2010 interior PM (IPM) machine, including the torque/power-speed characteristics, power factor, efficiency map, and drive cycle based overall efficiency. It is found that PM-assisted synchronous reluctance machines are the most promising alternatives to IPM machines with lower cost and potentially higher overall efficiency. Although IMs are cheaper and have better overload capability, they exhibit lower efficiency and power factor. Other electrical machines, such as synchronous reluctance machines, wound field machines, as well as many other newly developed machines, are currently less attractive due to lower torque density and efficiency.