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Hybrid and electric vehicle technology has seen rapid development in recent years. The motor and the generator are at the heart of the vehicle drive and energy system and often utilize expensive rare-earth permanent magnet (PM) material. This paper reviews and addresses the research work that has been carried out to reduce the amount of rare-earth material that is used while maintaining the high efficiency and performance that rare-earth PM machines offer. These new machines can use either less rare-earth PM material, weaker ferrite magnets, or no magnets; and they need to meet the high performance that the more usual interior PM synchronous motor with sintered neodymium–iron–boron magnets provides. These machines can take the form of PM-assisted synchronous reluctance machines, induction machines, switched reluctance machines, wound rotor synchronous machines (claw pole or biaxially excited), double-saliency machines with ac or dc stator current control, or brushless dc multiple-phase reluctance machines. [ABSTRACT FROM PUBLISHER]

Compressor electric motor drives play a key role in the energy consumption of residential refrigerators. Electrical efficiency, robustness to starting and overloads and speed variation range define the performance of compressor electric motor drives. Between the lowest cost fixed-speed split-phase capacitor grid-connected induction motor, with lower efficiency, and the higherefficiency grid-connected cage permanent-magnet (PM) rotor split-phase capacitor motor and the inverter fed variable speed PM synchronous motor of highest initial costs, we introduce in this paper a 2 speed grid-connected motor drive. The proposed topology uses a separate split-phase winding, cage-PM-4-pole rotor synchronous motor (PMSM) for low speed (4 poles) and a single-phase (main) winding for 2-pole operation. The tentative target is 85% efficiency at 50 W output for 4-poles (low speed) PMSM operation with good starting and about 60% efficiency in 2-pole (high speed) induction motor operation at 100 W, with smooth transients from low to high speed under full torque load. Circuit models for steady state and for transients with dedicated Matlab codes have been developed, with key FEM validation, to substantiate full scale experiments, and an optimal design methodology embedding both operation modes was put forward, as main theoretical contributions. [ABSTRACT FROM AUTHOR]