A New Modeling Approach for Permanent Magnet Vernier Machine With Modulation Effect Consideration

A dynamic nonlinear equivalent magnetic network (NEMN) method for a fault-tolerant permanent magnet Vernier machine is proposed in this paper. The key of this paper is to develop two models for no-load and on-load conditions, respectively, because the flux distribution under the no-load condition is different from that under the on-load condition owing to the modulation effect. The no-load model is built based on the precise air-gap modeling method, while the on-load model is developed based on the simplified air-gap modeling method. Meanwhile, a new circuit transformation method is provided for the on-load model to solve the difficulty of low convergence speed in the iteration process. Moreover, iron saturation and fringing effect are considered in the proposed NEMN models. Then, it is used to predict the air-gap flux density, cogging torque, back-electromotive force, and inductance. Finally, both the finite-element method and experimental tests are used to confirm the accuracy and effectiveness of the proposed models.