Optimization of added permanent magnet amount in synchronous reluctance machines for high performance

An optimizing method of adding permanent magnet into syrchronous reluctarce machines for high performance is presented. The method enables torque components from reluctance and permanent magnet to reach an optimal combination so as to obtain a maximum efficiency, higher power factor ina wi der speed range. Capability curves of synchronous reluctance combined with permanent magnet (SR-PM) machines are described for different quantities of permanent magnet. The interacting principle of reluctance and permanent magnet torque is discussed. Simulation results based on an integrated model of the SR-PM machine with a controller are presented to demonstrate the interaction of the two kinds of torques. Particularly efficiency, contours over the capability curves are to ustrated to show the effect of added permanent magnet amount. An optimizing criterion for added permanent magnet amount in SR-PM machine design is developed. Compared to induction, pure synchronous relietance, and non-optimized SR-PM zed SR-PM machines with same stator, the optimized SR-PM machine shows higher efficiency in a wider speed range.