Drive cycle analysis of a variable flux motor (VFM) with adjustable rotor-stator mechanism

This paper presents a variable flux motor (VFM) with an adjustable rotor-stator mechanism that is designed for electromobility applications. The built-in mechanism allows for the position of the rotor to shift relative to the stator thereby changing the rotor-stator air-gap magnetic flux. This allows for the electromagnetic characteristics of the motor to change with the operating conditions in a drive cycle. A prototype device is evaluated in an experimental setup to simulate the torque and speed variations expected in a drive cycle. The operation of the VFM with the built-in mechanism is demonstrated and the efficiency of the motor is evaluated at several critical points of the drive cycle. The results show that an averaged drive cycle efficiency of 92% is achievable which is an almost 6% gain in efficiency over an equivalent fixed flux electric motor applied to the same scenario.