Magnetic gear has high torque density and efficiency, and has a good application prospect in the field of low speed and high torque transmission. Accurate calculation of its air gap magnetic field is the key to analyze and design the magnetic gear. In order to improve the output torque of magnetic gear, the inner rotor is slotted, and copper bar is added in this paper. The air gap magnetic field of magnetic gear with rotor copper bar is calculated by two-dimensional analytical method. The solution domain is divided into four sub-domains, i.e., permanent magnets, air gaps, slots, and rotor copper bars. The solutions of Laplace's equation, Poisson's equation, and Helmholtz's equation are obtained by boundary conditions and continuity conditions. The distributions of air gap magnetic field, the induced current of rotor copper bars, and electromagnetic torque are obtained. The calculation results of this method are basically consistent with those of the finite element method, which proves the correctness and rationality of the analytical model.
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