Calculation Of The Permanent Magnet And Study Of The Speed Control System For The Squirrel Cage Type Magnetic Coupling

Magnetic coupling is a novel magnetic transmission mechanism, the torque can be transmitted through the air gap between the drive machine and the service machine. Compared with mechanical coupling, magnetic coupling has significant advantages, such as isolated vibration, no-load startup, overload protection and larger misalignment tolerance. When applied in speed governing condition, energy will be saved effectively, and it is more feasible and reliable than frequency converter and hydraulic coupler.The research background and significance of the squirrel cage type magnetic coupling are presented in this thesis, the influence of the permanent magnetic material development process on the magnetic coupling and the current research situation is analyzed, the advanced squirrel cage type magnetic coupling is put forward after comparing with the disk coupling and cylindrical coupling.Moreover, the tangential and radial equivalent magnetic circuit model are established, and the volume calculation formula of the permanent magnet is derived with the influencing factors analyzed.The permanent magnet is not only the magnetic source but also a part of the magnetic circuit, it is the foundation of energy exchange and transmission, it has a close relation with each performance index of the squirrel cage type magnetic coupling.As the working point of the permanent magnet will change due to the influence of armature reaction when running on-load, to prevent the permanent magnet from being completely demagnetized, the working point should not be lower than the demagnetization point.Therefore the working point must be checked to ensure the working point higher than the demagnetization point after designing.Based on the analysis method which combined magnetic circuit with diagram, an efficient analytical means is proposed for checking the working point of the permanent magnet in this thesis。To verify the validity of the magnetic circuit and obtain the varying pattern of the torque and the speed, finite element method is adopted here to establish the simulation analysis model of the squirrel cage type magnetic coupling. Its magnetic lines and magnetic field intensity distribution are studied, and the regulations of the torque and the speed in stable on-load running condition are derived.As the power is transmitted through the effective magnetic field in the air gap for the magnetic coupling, the output torque and speed can be adjusted by changing the contact area between the permanent magnet rotor and the squirrel cage type rotor.A speed regulation system is established to achieve automatic control in this thesis.The relationship between the effective contact length and the output torque and speed is obtained, and further analysis is carried out for the energy-saving principle.The push-pull mechanism is the actuator to adjust the air gap contact area, its kinematic accuracy is the direct determinant of the output torque and speed. A push-pull mechanism is put forward in this thesis, and the kinematics characteristics are analyzed by way of complex number vector method, The simulation software Adams is also used for auxiliary analysis and validation to ensure the accuracy and stability of the mechanism regulation.