Magnetic Circuit Analysis of Permanent-Magnet-Assisted Salient-Pole Synchronous Machines Under Steady States

Permanent-magnet-assisted salient-pole synchronous machines (PMa-SMs) are a new type of salient-pole synchronous machines that has PMs between the adjacent pole shoes. The PMs have the ability to improve the output power and the terminal voltage. In this paper, a simple magnetic circuit of PMa-SMs is presented. Using the magnetic circuit, the electric and magnetic basic characteristics of PMa-SMs are calculated. The results are compared with the results by measurements and finite-element analysis (FEA). They have shown that the magnetic circuit calculates the characteristics of PMa-SMs with satisfactory accuracy and that the computational time of the magnetic circuit is much smaller than that of FEA. Influence of the pole-shoe magnetic reluctances on the calculation accuracy by the magnetic circuit is also discussed, and some guidelines to enhance the accuracy have been presented.