Design methodology for variable leakage flux IPM for automobile traction drives

This paper presents a novel methodology for the variable leakage flux IPM (VLF-IPM) motor taking advantage of variable leakage flux property in the rotor core controlled by q-axis current without any additional components. The fundamental phenomenon is explained with FEA results, then, the theoretical equations expressing variable flux linkage controlled by q-axis current have been conducted. The proof-of-principle model was designed and the fundamental properties, such as torque-speed envelop and efficiency map, were evaluated. It was shown that the proposed motor can expand output power in the high speed region, and decrease energy consumption.