| In recent years,environmental pollution and energy shortage issues have led to the rapid development of new energy utilization.As a widely distributed and early-started renewable energy.wind energy shows strong vitality in the field of new energy power generation.As a new type of AC generator.the magnetic geared brushless doubly-fed motor(MG-BDFM)has the advantages of relatively simple structure.large speed range.relatively high efficiency,good heat dissipation performance,etc.,and it is suitable for gearless drive system,a potential application for wind power generation.Since the stator slot type affects the distribution of harmonic magnetic field and hence the performance of the motor,this thesis optimizes the stator slot shape in order to reduce the core loss of MG-BDFM.The main work of this thesis is as follows:(1)Based on the principle of magnetic field modulation,this thesis analyzes the magnetic field distribution in the air gap of MG-BDFM,and points out the conditions that the pole counts and speed of the inner and outer rotating magnetic fields and the modulation blocks need to meet for an MG-BDFM working stably.(2)With a specific MG-BDFM as an example,the way to obtain the magnetic field distribution,torque characteristics and loss characteristics of the motor by time-stepping finite element method is introduced in detail,and the harmonic content of the radial magnetic field in the model air gap is analyzed based on the simulation,which verifies the correctness of the above theoretical analysis.(3)With constant slot area,the slot geometry of the motor is optimized under same torque level for smallest core loss,in three approaches:changing only a single parameter of inner or outer stator slots.changing multiple parameters of inner or outer stator slots.and changing the parameters of inner and outer stator slots at the same time.The change rule of core loss under various schemes is summarized,and the stator slot geometry with the minimum core loss is obtained. |
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