Design Methodology for Variable Leakage Flux IPM for Automobile Traction Drives

This paper presents a novel methodology for the variable leakage flux interior permanent-magnet (VLF-IPM) motor taking advantage of the variable leakage flux property in the rotor core controlled by the q-axis current, without any additional components. The fundamental phenomenon is explained with finite-element analysis results; then, the theoretical equations expressing the variable flux linkage controlled by the q-axis current have been conducted. The proof-of-principle model was designed, and the fundamental properties, such as torque-speed envelope and efficiency map, were evaluated. It was shown that the proposed motor can reduce energy consumption on duty-cycle driving.