Transmission Performance Research Of Speed Adjustable Radial Flux Permanent Magnet Eddy Current Coupler

The radial flux type speed regulating permanent magnet eddy current coupler is a flexible transmission device,which realizes the torque transmission from the motor end to the load end,and has the advantages of high reliability,low cost,overload protection,high efficiency and energy saving.When the coupler is working,the alternating magnetic field is generated by the relative movement between the conductor and the permanent magnet,and the induced magnetic field in the conductor interacts with the original magnetic field to achieve the purpose of transmitting torque.In this thesis,the electromagnetic torque of the permanent magnet eddy current coupler is deduced and the influence of structural parameters on the transmission characteristics is simulated and verified by the method of electromagnetic theory combined with finite element simulation and experimental comparison and verification.A segmented conductor structure permanent magnet eddy current coupler is proposed to improve the speed regulation characteristics of high-power couplers.By establishing a layer model,the path of the magnetic flux loop in the coupler model is analyzed,and the yoke,conductor,and air gap are regarded as the magnetoresistance by the equivalent magnetic circuit method,and the permanent magnet is regarded as the magnetomotive.The loop simplifies the magnetic circuit,does not consider the magnetic saturation situation,and uses the superposition theorem to calculate the effective magnetic flux passing through the magnetic resistance of the yoke in the stationary state.An analytical formula for electromagnetic torque is derived.In order to visualize the distribution law of the air-gap magnetic field of the permanent magnet eddy-current coupler,Ansys maxwell finite element simulation software was used to study and analyze the air-gap magnetic field,and at the same time,the air-gap width and conductor thickness were changed to explore its influence on the air-gap magnetic field.The influence of the induced magnetic field on the air-gap magnetic field under slip is analyzed.Starting from the structural parameters such as air gap thickness,conductor thickness,permanent magnet size,a 900KW radial flux type speed-regulating permanent magnet eddy current coupler is designed,and the effect of structural parameters on the output electromagnetic torque at different speeds is explored.It is concluded that the thickness of the air gap is negatively related to the output torque,the width and thickness of the permanent magnets are positively related to the output torque,and the conductor thickness will show different laws under different slips.Conductor thickness is positively correlated with output torque under low slip,When the slip increases,the conductor thickness is negatively correlated with the output torque.By building an experimental platform,the mechanical characteristics of the permanent magnet eddy current coupler with conventional conductor structure are tested,and the simulation scheme and the accuracy of the results are verified by comparing with the simulation values.When the slip is low,the error between the finite element simulation results and the experiment is within 7%,which cannot be verified under high slip due to thermal constraints.The speed regulation characteristics and speed regulation ranges for different load types are explored under this structural model.Focus on the research of the speed regulation range of the permanent magnet eddy current coupler for the quadratic load,and propose a segmented conductor structure.The Ansys maxwell finite element simulation software is used to calculate the mechanical characteristics of the coupler under this model.The simulation scheme of permanent magnet eddy current coupler model is designed and the influence of its segmented structure on transmission characteristics and speed regulation range is studied.It is concluded that when the segment ratio is constant,the maximum output torque of the quadratic load coupler with a load factor of 2.76x10^-3 decreases slightly,and the starting torque of the coupler increases;when the load factor of the quadratic load remains unchanged,the maximum speed that the coupler can output is slightly reduced,but the overall speed regulation range is increased.