Research On Working Performance And Speed Regulation Characteristics Of Magnet-rotating Magnetic Coupler With A Slotted Conductor

As a permanent magnet transmission device based on the principle of electromagnetic induction,the magnetic coupler is widely used in electric power,petrochemical,pump,water treatment,agricultural irrigation and other industrial fields.The magnetic rotor and the conductor rotor can transmit torque with no physical contact,and the coupler also has the advantages of soft start,reduced shock and vibration,no need for precise centering,energy saving and environmental protection,and low maintenance costs.In view of the above advantages,the research on the magnetic transmission technology has profound significance in both academic and engineering application.In this dissertation,the research on magnet-rotating magnetic coupler with a slotted conductor is mainly focused on as follow:?1?The air gap magnetic field and electromagnetic torque of magnet-rotating magnetic coupler with a slotted conductor is analyzed and calculated.Reasonable assumptions are made based on the coupler model,and the layer model theory is adopted to divide the coupler into several regions,and the vector magnetic potential of each layer is analyzed,and then the boundary conditions at the common boundary of adjacent regions are used to solve the vector magnetic potential.After that,the specific value of the vector magnetic potential and the magnetic density distribution in the air gap region are obtained.Finally,the electromagnetic torque of the coupler is calculated by combining the three-dimensional end correction coefficient.?2?FE method is used to analyze the transmission performance and dynamic characteristics of the magnet-rotating magnetic coupler with a slotted conductor.The static and transient magnetic fields of the coupler are analyzed.It is found that the static magnetic density shows an irregular sinusoidal distribution under the influence of the slots on the air gap magnetic field distribution to different degrees,and the transient magnetic field is more irregularly distributed under the influence of the induced magnetic field,and the magnetic density waveform has more distortion.Using the finite element analysis software,the output speed and torque characteristics of the variable air gap thickness and magnet rotation angle are simulated and analyzed.The larger the air gap thickness or the magnet rotation angle,the smaller the output speed and the smaller the reduction.Due to the influence of cogging torque,the output speed and torque both fluctuate to a certain degree,and the degree of fluctuation is different under different air gap thicknesses and magnet rotation angles.The axial force of the variable air gap thicknesses and the rotation angles of the magnet is analyzed with the change of speed difference and air gap thickness,whether the coupler is at a certain air gap thickness or the magnet rotation angle,the working axial force decreases with the increase of the speed difference and eventually stabilizes.The larger the air gap thickness,the smaller the axial force and the reduction is also smaller,in addition,when the coupler works at different speed differences,the rotation of the magnet will cause the axial attractive force and repulsive force to change at the same time,so it presents a variety law of axial forces with the rotation angle of the magnet.By analyzing the relationship between the eddy current loss and the rotation angle of the magnet under different speed differences,it is found that the eddy current loss of the coupler decreases with the increase of the rotation angle of the magnet,and the larger the rotation angle,the smaller the reduction eddy current loss.?3?The speed regulation characteristics of the magnet-rotating magnetic coupler with a slotted conductor under different working conditions are studied.The parameterized simulation in the nonlinear finite element method is used to obtain the mechanical characteristic diagram of the relationship between the output speed and the torque of the coupler.Based on this,the power characteristics of the coupler are calculated and analyzed to obtain the corresponding point of maximum output power is different from that of the maximum electromagnetic torque and the slip rate corresponding to the maximum output power point is less than the critical slip rate.According to different load conditions,the speed regulation characteristics during the process of magnet rotation and axial movement are obtained and analyzed respectively.The starting capacity with load during the rotation of the magnet is lower than that of the axial movement process,and under the condition of variable torque load,the speed adjustment range of the axial movement is significantly larger than that of the magnet rotation process.For both speed adjustment processes,the speed adjustment range under the variable torque load condition is significantly larger than that of constant load condition.When the coupler is used to adjust the speed of a fan or a pump,the speed adjustment range increases first and then decreases during the increase of the load factor.When the load factor k_f is 1.76×10^-5,the speed regulation interval of the magnet rotation speed regulation process is the largest.When the load factor is around 2.83×10^-5,the axial movement can be used to complete a large range of high power speed regulation processes.?4?The speed regulation characteristics of the coupler under different structural parameters and the energy consumption in the speed regulation process are obtained respectively.The influence of the main structural parameters of the slotted-type copper conductor on the speed regulation performance has been studied,including number of slots,thickness and cogging ratio.Within a certain range,the maximum electromagnetic torque increases with the increase of the number of slots,and the speed regulation performance gradually improve,and the critical slip rate does not change.As the thickness of the copper disk becomes greater,the speed regulation performance decreases,and the larger the thickness,the smaller the impact.The start-up performance and speed regulation performance of the coupler hardly change when the cogging ratio increases.Comparing the influence of various parameters on the speed regulation characteristics,it can be seen that the thickness of the copper disk has the greatest influence on the speed regulation performance.In addition,the energy consumption during the speed regulation process of the axial movement and the rotation of the magnet are calculated respectively and compared based on the force situation.It is obtained that the energy consumed during the rotation of the magnet under a low speed difference is greater than the axial movement.