Structural Design And Dynamic Characteristics Of Drum-type And Solid Magnetic Couplers

Drum-type and solid magnetic coupler?DSMC?is a new kind of transmission device which is based on the electromagnetic induction principle.The speed and torque of the output terminal are adjusted by changing the axial meshing length of the permanent magnet rotor and the conductor rotor,which not only has the advantages of traditional magnetic coupling,such as non-contact transmission,overload protection,adaptation to harsh environment,etc,but also can achieve low-load startup of the motor under heavy load,at the same time,this coupler has a significant energy saving effect when applied in fans and pumps.Based on the the structural characteristics and working principle of the DSMC,the influence of different structural parameters of DSMC on the transmission performance is studied,several aspects of research are studied as follows:Firstly,in this paper,the electromagnetic torque and eddy current loss of the DSMC in the permanent magnet gap are calculated and analyzed.Based on the structure and speed regulation principle of the DSMC,the magnetic field of the DSMC is simplified as a magnetic circuit,a closed loop composed of a pair of magnetic poles is taken as the object of study,the main magnetic circuit and the magnetic flux in the magnetic circuit are calculated,the magnetic flux of the main magnetic circuit is obtained by Kirchhoff's law.In order to reduce the error of the electromagnetic torque of the magnetic coupling caused by the end effect,the calculation formula of the electromagnetic torque is deduced based on the three-dimensional correction coefficient,the magnetic torque density of the magnetic coupler is obtained.The skin effect and the equivalent penetration depth of the eddy current on the copper ring of the DSMC are analyzed theoretically,the formula for calculating the eddy current density of copper ring is deduced according to Maxwell's equation and Lenz's law,the calculation formula of the eddy current loss of copper ring in one cycle is obtained.Secondly,in order to improve the performance of magnetic coupler drive and material utilization,by means of Magnet finite element analysis software simulation analysis of permanent magnet magnetic coupler arranged in the gap length diameter ratio was 0.255,0.294,0.333,0.372,0.412,0.451,the influence of the parameters such as the number of pole pairs,the polar arc coefficient of permanent magnet,the axial length of the permanent magnet rotor and the conductor rotor,and the thickness of the copper ring on the transmission performance of the magnetic coupler,the results show that when the center angle of the arc of the adjacent two magnetic pole gap is 6 degrees,that is to say,the polar arc coefficient of the permanent magnet is 0.8,the magnetic pole number is 6,the thickness of copper ring is 4mm,and the thickness ratio of copper ring is 1,the magnetic coupler has a large transmission torque per unit volume,which improves the utilization of the material and reduces the manufacturing cost.Thirdly,the relationship between the output speed and the output torque of the magnetic coupler is simulated and analyzed by using Magnet finite element analysis software,the mechanical characteristic curve of the DSMC is obtained,the stable operating range is 0-_ms or_mn-₀n,and the unstable operating range is_ms-1or0-_mn,compared with the disc type asynchronous magnetic coupler,the speed range is wider,the stability running range is bigger,and it can adapt to the disturbance of load,and has larger transmission torque under the condition of low speed.Based on the simulation analysis of the speed regulation of the magnetic coupler under constant load and variable load,under the constant load condition,the output speed decreases with the decrease of the meshing length,in the variable load conditions,the output speed of the magnetic coupler decreases with the increase of the fan scale coefficient when the meshing length is constant.Finally,when the magnetic coupler is operated under constant torque load conditions,the output power of the motor is constant and the output torque remains the same,so the power of the motor is constant,therefore,the magnetic coupler has no energy saving effect under the constant load condition.Under the condition of variable load of wind turbine and pump,through the analysis of the characteristic curve of the fan,compared with the traditional way of adjusting the size of the damper through the baffle to change the pipe network characteristic curve,the H-Q characteristic curve of the fan is adjusted by the speed-type magnetic coupler,which can achieve the satisfactory energy-saving effect.