Calculation and Analysis of Flux Leakage Coefficient of Interior Permanent Magnet Synchronous Motors With Fractional Slot Concentrated Windings

Permanent magnet (PM) motors adopt interior V-type PMs and fractional-slot concentrated winding for improving the torque density and efficiency. However, the no-load magnetic coefficient will be increased, which would reduce the utilization rate of the PM. The structure parameters of the rotor should be designed reasonably, especially the bridge. This paper calculates the no-load leakage coefficient by establishing the analytical model of the no-load magnetic coefficient. It shows that, the bridge size has an important effect on the no-load magnetic coefficient. The analysis results are verified by the two-dimensional finite element analysis and tests.