Calculation of D- and Q-axis inductances of axial flux permanent magnet synchronous motor with combined magnetic poles

D- and q-axis inductances are crucial parameters influencing motor performance. An inductance calculation method based on quasi-3D analytical model for axial flux permanent magnet synchronous motors with combined magnetic poles with fractional slot concentrated windings is proposed. The complex magnetic circuits and variable magnetic saturation states at different radii are considered by the proposed method. Then the accuracy of inductance calculation is improved compared with traditional method based on average radius analytical model and verified by the 3-dimensional finite element method simulation.