Introducing a New Biased-Flux Permanent Magnet Motor with Enhanced Efficiency and Power Factor

This paper investigates and compares a novel biased flux permanent magnet (BFPM) motor with a conventional inter-modular permanent magnet motor. The proposed motor stator is made up of a C-shape nonmodular piece and six modular E-shape pieces cooperating with permanent magnets (PM) that are in stator teeth and between the stator modules. This C-shape biased flux permanent magnet (CBFPM) structure results in better air gap flux density modulation and improved torque ripple, efficiency, and power factor. The proposed CBFPM and conventional BFPM motors are compared in terms of the back-EMF, cogging torque, torque, overload capability, static torque, and no-load and full-load flux line and flux density. It is proved that the proposed topology can drastically improve the power factor as a crucial index in the stator-PM motors.