The Research Of Permanent Magnet Torque Motor Which Have The Halbach Structure Of Magnetic Pole Based On Magnetic Poles Whose Width Is Unequal

The use of permanent torque motor which is directly coupled to the load could reduce the transmission error and loss caused by mechanical transmission. Using the form of permanent can not only improve stiffness and efficiency of the mechanical drive system,but also could improve the reliability of mechanical transmission system. With the development of permanent magnet direct drive motor which will have higher torque density, lower torque ripple and lower cogging torque, we must improve the fundamental amplitude and sinusoidal waveform of air gap flux density so that the use of traditional radial magnetization and parallel magnetization on the structure of magnetic pole is difficult to meet this requirement. It is difficult to find the permanent magnetic materials and improve magnetizing technology. Therefore, we can improve the fundamental amplitude and sinusoidal waveform of air gap flux density by studying the new magnetic structure.On the basis of the research achievements that the domestic and foreign scholars did about Halbach array, firstly, this paper gives a detailed introduction to the basic principle of Halbach array and the electromagnetic design of Halbach array motor. Secondly, the paper provides a Halbach array(based on magnetic poles whose width is equal) motor designed by the method of the FEM simulation and the data acquisition of the motor’s output torque and cogging torque by using existing experimental equipment. Thirdly, by comparingexperiment results with the FEM simulation data, the paper verifies the correctness of the finite element method. The correctness of the finite element method lay the theoretical foundation for the study of Halbach array based on magnetic poles whose width is unequal.On the basis of Halbach array structure(based on magnetic poles whose width is equal), in order to increase the motor torque density and reduce the torque ripple, we can increase the magnitude of fundamental of air gap flux density and reduce the harmonic distortion. So,according to the Halbach array magnetic pole structure, the paper does the optimization design of pole and slot combination, magnetic pole ratio and magnetization angle to obtain the optimal pole ratio and magnetization angle. And, according to the optimization parameters, we can build the optimization model. By the establishment of optimization model, the paper provides the analysis of the optimization scheme by using the finite element method. Results show that the use of Halbach structure of magnetic pole based on magnetic poles whose width is unequal can succeed in increasing torque density of the motor and reducing the torque fluctuations.