Work Performance Study On Speed-control System Of Axial-flux Asynchronous Magnetic Coupling In Variable Load

Speed-control System of Axial-flux Asynchronous Magnetic Coupling in Variable Load(SSAAMCVL) consists of motor, axial-flux asynchronous magnetic coupling and fan or pump variable load. Speed control system uses magnetic force to transmit and change air gap flux density by changing the distance between active disc and driven disc.so the induction of electromagnetic torque changes and finally reach the purpose of regulating rotor speed. On the one hand, the system uses the advantages of physical isolation in transmission and can work stable in the thermal power plant, coal mine and other bad environment filled with coal, ashes, corrosive gas. The speed control system has low manufacture cost, maintenance cost, high reliability and long service life. On the other hand, using asynchronous magnetic coupler to adjust speed in variable load such as fan and pump can greatly reduce the power consumption. When the fans or pumps rotation speed and flow during maximum of 80%, system uses only 64% energy compared with using the ventilation door or dam-board. So it can save the energy and the cost of production greatly. Therefore, the research on SSAAMCVL has greatly practical significance and application value. The current study of permanent magnetic coupler is sufficient, but not enough for speed-control system in variable load. Based on the situation, this article selects SSAAMCVL as the research object and mainly do the following several aspects of research.(1) The working condition of SSAAMCVL is more complicated than constant load. The theoretical calculation should be done to analyze the performance of speed adjustment and determine the parameters. This paper establishes mathematical model under the working principle of axial-flux asynchronous magnetic coupling. The vector magnetic potential method is used to calculate the air gap flux density value and its distribution between active disc and driven disc. And the flux density formula is calculated to get the value of air gap flux density and its distribution by using Matlab software. The magnetic coupling torque and axial force formula under normal operation is derived. Finally, The working efficiency of the SSAAMCVL in a stable runtime is calculated by using fan class variable load torque and power equation.(2) The startup process and the stability condition is very complicated in SSAAMCVL. In order to improve the startup performance and stable working performance of the system, three-dimensional model is established by using the Magnet finite element analysis software. The speed-control system startup performance is analyzed under different load coefficient and different input rotational speed including torque, speed and axial force. In order to determine the best matching parameters, the flux density, rotational speed, torque, axial force, eddy current loss and the working efficiency of SSAAMCVL are analyzed. So that on the premise of meeting working conditions, the system has short starting time, small startup impact, stable operation performance in transmission and high work efficiency.(3) In order to research the working process of SSAAMCVL, The paper simulate the flux density, torque and rotate speed of magnetic coupler in different disc spacing by using Magnet finite element analysis software. The eddy current loss and transmission efficiency during speed control process are also analyzed. The speed adjusting range, torque adjusting range, and the transmission efficiency under different load coefficient and different input rotation speed are researched. The best load coefficient and input speed are chosen so that the system has the best comprehensive performance during speed control. That means the system has large adjusting range of rotation speed and torque, high precision, small axial force adjustment and high efficiency. The working parameters of speed-control system in different disc spacing are measured to research rotate speed, torque, the transmission efficiency during speed adjust.(4) The experimental platform of SSAAMCVL is set up to prove the results of theory and simulation analysis above. The stable working parameters of the speed control system such as speed, torque, the transmission efficiency are measured in order to analyze the influence of different input speed for the working performance. The experiment parameters are recorded in different input speed, and the influence to speed adjusting range, torque adjusting range and the transmission efficiency are analyzed. Finally, the energy-saving effect of SSAAMCVL is analyzed.