Structure Analysis And Parameters Optimization Of Excitation System For Asynchronous Magnetic Coupling Based On Squirrel Cage Rotor

Squirrel Cage Rotor Asynchronous Magnetic Coupling (SCRAMC) has advantages of small volume, light weight, no environmental pollution, the high execution efficiency and adjust the output rotating speed and torque precisely, etc.The numerical integral method combines with regional division method to be used for leakage coefficient analysis and calculation of the SCRAMC. According to leakage flux path of the permanent magnet to carry out geometric graphics division and induction, and based on the numerical integral method, a leakage permeance mathematical model is established according to geometric graphics which form the integral path, hence, the integrity and generality of the leakage coefficient calculation is ensured. The proposed method is suitable for computer programming, and it is abled to be used to analyse and optimize structure parameters of excitation system.According to the principle of SCRAMC operation is similar to cage type asynchronous motor and permanent magnet generator, giving calculation method of SCRAMC structural parameters of tile type radial magnetization and rectangular tangential magnetization, based on the existing standard cage rotor, use design method of permanent magnet generator excitation system and improve on it, to calculate structure parameters of permanent magnet rotor and check magnetic circuit with cage rotor structure parameters.Take for example the permanent magnet is tile structure in the outer rotor, theoretical model of air-gap magnetic field is established, it is used to analysis calculation result, so know, along the air-gap magnetic field of radial distribution is main factor of influence SCRAMC work performance. On this basis, using the finite element simulation software has carried on the static and transient simulation for SCRAMC magnetic field of two radial magnetizations (pure radial magnetization and parallel radial) of the structure. In the static magnetic field analysis, magnetic circuit and air gap flux density waveform is analyzed mainly, so know, tile type radial magnetization can narrow volume of SCRAMC and air gap flux density of pure radial magnetization is higher than parallel radial.In the analysis of the transient magnetic field, the air gap flux density harmonic and armature reaction influnces to air-gap magnetic field is analyzed mainly, Air gap flux density harmonic effects on size and volatility of the electromagnetic torque and the method of selects appropriate pole arc coefficient is presented in this paper,can reduce air gap flux density harmonic.When SCRAMC excitation system is designed,due to leakage coefficient and armature reaction magnetomotive force cannot be determined, to calculate the structural parameters of excitation system is not accurate, so adopt parameters method combined with finite element simulation software to optimize the structural parameters. In the optimization process, permanent magnet poles,magnetization direction size, air-gap size,iron yoke thickness and pole arc coefficient which effects on air-gap magnetic field and electromagnetic torque is analysed.For optimized excitation system has carried on the finite element simulation and experimental validation, to prove design method of SCRAMC excitation system in this paper has good feasibility and reliability.