Design and evaluation of a novel controllable leakage flux permanent magnet motor with wide speed ranges

This paper presents a novel type of controllable leakage flux interior permanent magnet synchronous motor (CLF-IPMSM) with wide speed ranges. The leakage flux of the machine can be controlled by the q-axis current. When VLF-PMSM is under high speed and light load, there will be a considerable leakage flux inside the rotor, which reduces the flux-weakening current. However, when the motor is under low speed and heavy load, there will be little or no leakage flux inside the rotor, enhancing its torque output capacity. Therefore, the motor can maintain high efficiency in a wide speed range. The performance of VLF-IPM is compared with that of conventional IPM by the 2D finite element analysis method, and the results verified that CLF-IPMSM could maintain high efficiency in a wide speed range.