Analytical model of no-load axial force for electric propulsion conical motor in electric aircraft

Abstract

In the field of electric aircraft, the axial force of the conical motor is used to offset propeller thrust and reduce bearing wear. For the problem of accurate calculation of the no-load axial force of the conical motor, combined with the characteristics that the rotor magnetic bridge of the hybrid conical inner-mounted permanent magnet synchronous motor (HC-IPMSM) is easy to be saturated and difficult to be calculated analytically, an equivalent analytical calculation method is proposed. According to the principle of constant air-gap magnetic flux, the HC-IPMSM is equivalent to many cylindrical surface-mounted permanent magnet synchronous motors (CY-SPMSM), and an analytical model is gained. Combining with the scalar magnetic potential Laplace equation and Poisson equation, the air-gap flux density distribution on the rotor surface is calculated. And finally, the no-load axial force of the motor is obtained by using the cone angle and the Maxwell stress method. Simulation and experiments verify the correctness and validity of the analytical model.