Reduction of Iron Loss and Back EMFs of the Doubly Salient Synchronous Reluctance Motor by Estimation of Flux Linkage

A doubly salient synchronous reluctance motor with concentrated winding exhibits large inductance variation, which generates the large flux variation in the rotor when the sinusoidal current is applied to the stator windings. The flux variation generates the iron loss and high harmonics of back EMFs, then decreases the efficiency and maximum output power especially at high-speed region. Therefore, it is necessary to reduce the inductance harmonics or the flux harmonics. In this paper, the d- and q- axes flux linkages are estimated by their inductances and currents. Then, flattening control of flux linkages is performed using PI control instead of current. 2-D finite element analysis results indicate that the proposed method reduces the iron loss and the back EMF harmonics, and improves efficiency and maximum output power in the high-speed range.