The Approach for Suppressing Intrinsic Shaft Voltage by Segmented Skewed Poles in Permanent Magnet Synchronous Motors

The intrinsic shaft voltage caused by the disequilibrium of magnet circuit in permanent magnet synchronous motors(PMSMs) will damage the bearing seriously. In order to suppress the intrinsic shaft voltage preferably, it is necessary to analyze the characteristics of intrinsic shaft voltage qualitatively. Following the magnetic-circuit method and Faraday's law of electromagnetic induction, an analytical model of intrinsic shaft voltage has been proposed. The analytical model can clearly show the harmonic components of intrinsic shaft voltage and the relationship between intrinsic shaft voltage and electromagnetic parameters, which is an important precondition for suppressing intrinsic shaft voltage. Considering the influence of segmented skewed poles, the analytical mode can calculate the optimal number of segmented slices and skew angle, which can successfully avoid intrinsic shaft voltage. In order to testifies the efficacy of the analytical model, the amplitudes and harmonic frequencies are calculate by finite element method (FEM). The results received by the analytical model agree well with the FEM result, which proves the precision of the analytical model.