Research On Torque And Loss Characteristics Of Field Modulated Magnetic Gear

Field modulated magnetic gear transmits power through magnetic field coupling,and its torque density is basically the same as that of mechanical gear.It has the advantages of no contact,no wear,no lubrication,low noises and overload protection,but it also has the disadvantages of low transmission efficiency and high cost.Torque and loss are important evaluation indexes of transmission device.Finite element model can be used to analyze the evaluation indexes of various complex structures and special working conditions.While the calculation accuracy is high,the calculation costs a lot time.The analytical method can directly express the influence of structural factors on electromagnetic field distribution,save the time of modeling and finite element calculation.It is of great significance for the design and optimization of magnetic gear structure.The main research contents are as follows:Analysis of electromagnetic field working principle of field modulated magnetic gear.On the basis of qualitative analysis of the working principle of magnetic gear,the causes of torque ripple and eddy current loss are clarified.The precise subdomain method is used to solve the electromagnetic field distribution of magnetic gear under different conditions,and the accuracy of the analytical model is verified by comparing with the finite element results.Analysis of torque characteristics of field modulated magnetic gear.Maxwell stress tensor method is used to calculate the torque ripple of the inner and outer rotors,the maximum stall torque of the inner rotors and the maximum output torque of the outer rotors.Analyses the effects of magnetization mode,polar number of permanent magnet,radial size and polar arc coefficient on torque characteristics.Analysis of loss characteristics of field modulated magnetic gear.An analytical model of time-varying motion electromagnetic field considering eddy current effect is established.Poynting’s theorem is used to calculate eddy current loss of permanent magnet,and the influences of magnetizing mode,rotational speed,radial size and polar logarithm on eddy current loss of permanent magnet are analyzed.Multi-objective optimization design of field modulated magnetic gear.The orthogonal experiment method is used to analyze the influence weights of each factor on torque and loss characteristics and the interaction between each factor.The Pareto optimal solution is determined by combining BP neural network and non-dominated sorting genetic algorithm.Design and test of magnetic gear prototype with magnetic field modulation.According to the results of multi-objective collaborative optimization,combined with the application requirements of the actual project,the prototype test platform was designed and built,and the input and output speed and torque were tested.The maximum static torque relative error of the inner rotor is 13.79%.