Research On High Ratio Magnetic Gear Of The Reluctance Type

Recently, although gear transmission occupies a very important position in modern power transmission system, the existing-gear which relies on direct contact is most of traditional mechanical gear. Compared to the traditional mechanical gear, the new-emerging magnetic gear has the advantages of low noise, high efficiency, easy maintenance, high reliability, long service life and overloaded protection etc. So there is a broad application prospect in many fields of industry and agriculture etc.The working principle of the magnetic gear mainly depends on the coupling effect of the magnetic field to transfer the torque and the rotational speed. There is no mechanical contact between the input part and the output part of the magnetic gear. Based on the principle of the reluctance motor, the flux always tries to go through the minimum reluctance path. Firstly, referring to the character of torque of reluctance motor, the structure character and the operation principle of high ratio magnetic gear of the reluctance type are analyzed in this thesis. The magnetic gear of 25:1 ratio,4 pairs of stator and 1 rotor pole is projected. Then, the new structure is simulated stactically by using the finite element analysis software-ANSYS. And the distribution of magnetic field lines, magnetic field intensity and the distribution of magnetic induction vector are achieved. The torque of the magnetic gear is calculated. And the relation curve among the torque, the mechanical angle and the electric angle is acquired. Moreover, the mathematical model of the magnetic gear is established by the method of equivalent magnetic circuit and equivalent electric circuit.Then, on the basis of the static simulation, the distribution of magnetic vector and magnetic lines is discussed by Ansoft in the transient case. In addition, the simulation of dynamic process of the torque of external rotor is analyzed. The results of simulation show the torque of external rotor without the loss in 3 weeks, and the target of the synchronous rotation without load is achieved.Finally, through the analysis of the dimentions and internal parameter of the magnetic gear, the curve among the torque, the length of the permanant magnetic pole, the height of the tooth and the width of air gap is drawed. Based on the actual level of engineering process, the magnetic gear is optimized. Refering to the principle of motor-designed, the hysteresis loss and eddy current loss of the magnetic gear are discussed.