The analysis of air gap flux and optimization of rare earth magnet thickness of IPM synchronous machine

The magnetic field of the interior permanent magnet (IPM) comes from permanent magnet (PM), and there exists a reasonable value for the dosage of PM material when the machine´s performance is constant. This paper presents the restriction condition of the rare earth magnet thickness in IPM synchronous machine; under the air gap length be constant, we analyzes the relation between the rare earth magnet thickness and air gap flux density, and the per pole flux respectively; at the same time in order to keep leakage flux constant, under the air gap length variety, we discusses the relation between air gap length and the non-magnetic bush thickness, and the rare earth magnet thickness respectively, then point out contributions of the rare earth magnet thickness to air gap flux.