Due to the magnetic saturation characteristic of the interior permanent magnet synchronous motor （IPMSM）， there is no effective method to analyze the radial electromagnetic force on the stator of PMSM. It is also disadvantageous to suppress the electromagnetic vibration and noise of the motor in the early stage of design and development. An analytical calculation model of electromagnetic force is presented to solve the problem of rotor unsymmetrical magnetic saturation of IPMSMs. By combining the winding function method with the equivalent magnetic circuit method， the magnetic dynamic potential of the motor considering the electromagnetic saturation is derived. The equivalent air gap permeability of the motor is calculated by using Carter factor. The air gap magnetic field model is established by the method of magnetic potential multiply permeability， and the analytical model of the radial electromagnetic force of the motor is finally established by the Maxwell stress equation. Finally， the accuracy of the model is verified by finite element method. The model can reflect the relationship between the electromagnetic force and the structure parameters of the motor， and is helpful to improve the structure of the motor quickly in the design stage to suppress the electromagnetic vibration and noise.
