| Drum-type speed-control asynchronous magnetic coupler(DSAMC) is a new kind of transmission device which is based on the electromagnetic induction principle. Not only does it has the advantages of the traditional magnetic couplers, such as non-contact transmission, vibrational isolation, overload protection and so on, but also can regulate the output speed by adjusting the action length between the inner rotor and the outer rotor according to the actual working conditions. When driving pumps and fans, it can get good energy-saving effects. As a result, the magnetic coupler is widely used in many mechanical transmission fields, it has essential engineering application value, and theoretical study of the DSAMC has very important academic value. Aspects about the DSAMC is mainly focused on as follows:Firstly, magnetic circuit model of the coupler is developed to analyze and calculate the magnetic torque of the DSAMC, the inter roter is double-layer solid rotor. The equivalent magnetic circuit method is used to analyze and calculate the main reluctance, leakage reluctance and magnetomotive force in the magnetic circuit model. Magnetic induction intensity in the air gap which is in the static state can be solved by using the Kirchhoff’s law, then, the final torque expression is acquired by combining the torque formula and three dimensional correction coefficient. The transmission efficiency formula can be derived, and get the conclusion that the sum of the efficiency value and the slip value is 1.Secondly, the overall magnetic induction intensity and the magnetic induction intensity in the air gap of the magnetic coupler in static state and in transient state are studied, and the conclusion is gotten that the value of magnetic induction intensity in the transient state is bigger than the value in the static state. The distribution of the current density in the copper is studied, the distribution law of the axial current density which has influence on the transmission performance of the magnetic coupler is gotten. The distribution law is that the biggest value of the current density occurs in the center of the copper, and gradually diminish along the axial direction. The finite element simulation is used to get the relationship between magnetic torque and the slip, the result indicates that magnetic torque grows bigger when the slip becomes bigger. The simulation value is compared with the calculated value, and they have good consistency. The relationship between transmission efficiency and slip is that the efficiency decreases when the slip increases, and the sum of the efficiency value and the slip value is 1.Thirdly, when the load is constant or variable, torque formula and the correction coefficient are combined to get the adjustable-speed formula, and compared with the simulation value, the result indicates that they have good consistency. Theoretical and simulation analysis are carried out when the magnetic coupler drives different loads, the results indicate that when coupler drives constant load, it can not save energy, when it drives variable load, it has good energy-saving effects. Finite element simulation is used to analyze the speed-control performance when coupler drives constant load and variable load. The results indicate that when magnetic coupler drives constant load, output speed decreases when the input speed decreases, but the slip remain constant. When magnetic coupler drives variable load, output speed and slip decrease when the input speed decreases.Finally, the experimental platform for speed control performance is developed. The relationship between action length and output speed, slip and speed difference under different input speeds or loads can be got when the coupler drives constant load, and the results has a good consistency with the simulation value and calculation value. When the coupler drives fan, the relationship between action length and output speed and slip can be got, and it also has a good consistency with the simulation value and calculation value. |
PDF Full Text Request