Flux-weakening performance of series permanent magnet memory machine

This paper presents the theoretical analysis of flux-weakening performance of series permanent magnet (SPM) memory machine. A modified circle diagram is proposed to graphically illustrate the maximum torque per voltage (MTPV) flux-weakening control strategy for the memory machine. It is shown that a maximum torque capacity can be obtained by controlling the armature current and magnet flux simultaneously. The influence of machine parameters on the performance of PM memory machine is also investigated. The results can be used to design a PM memory machine for a given flux-weakening performance.