Internal Permanent Magnet Motor with U-shaped Permanent Magnet Arrangement to Enable a Small Magnetization Current with High Power and Efficiency for Electric Vehicles

Recently proposed variable-magnetization interior permanent magnet (VM-IPM) motors can vary the magnetization of a permanent magnet (PM) to operate at high efficiency over a wide speed range for electric vehicles. However, there is a concern that the variable-magnetization of PM enabled by a low magnetization current is incompatible with high power. In this study, we proposed VM-IPM motors with an added second layer capable of varying small magnetization current and producing a power of 100-kW class. Characteristics of the VM-IPM motor is discussed while comparing with Nissn LEAF motor. Our results confirmed that the proposed motors could vary the magnetization of PMs by less than twice the rated current and achieve high efficiency and output power of 100 kW over a wide speed range.