Analytical Prediction of D- and Q-Axes Inductance for Dual Three-Phase Surface-Mounted Permanent Magnet Motor Accounting for Eccentric Pole and Tooth Saturation

This article presents an analytical model to calculate the d - and q -axes inductance of a dual three-phase surface-mounted permanent magnet motor accounting for eccentric pole and tooth saturation. The novel method combines the advantages of the subdomain model and lumped parameter magnetic circuit model (LPMCM). This motor is divided into several subdomains. And the eccentric pole is further subdivided into multiple symmetrical regions. Based on Poisson's and Laplace's equations, the subdomain model is established. The reluctance of the tooth and the tip is calculated by the subdomain model and LPMCM. According to the relationship between tooth reluctance, tip reluctance, and the corresponding air-gap reluctance, the equivalent air-gap magnetic density coefficient is obtained. Based on the coefficient, the new air-gap magnetic density and tooth magnetic density are solved. For the solution of saturation, this article compares the density of two adjacent solutions until the error between the two is very small. Based on the iterative calculation, the d - and q -axes inductance is obtained. The finite-element method and experiment are employed to validate the analytical model.