Permanent Magnet Demagnetization Physics of a Variable Flux Memory Motor

The variation characteristics of flux density and field intensity of trapezoidal permanent magnets (PM) in the variable-flux memory motor (VFMM) under different demagnetizing magnetomotive forces are analyzed using the finite element method. A prototype machine is fabricated and tested. Good agreement between the calculated and experimental results is achieved. It confirms the easy controllability of air gap flux of the developed VFMM with trapezoidal PMs.