Analysis of Multi-disc Coreless Permanent Magnet Synchronous Motor Based on Halbach Array

　　Analysis of Multi-disc Coreless Permanent Magnet Synchronous Motor Based on Halbach Array
　　Disc permanent magnet synchronous motor is a new type of high performance servo motor developing in recent years. It has the characteristics of short axial size, light weight, small volume, close structure and so on. The motor can be made into a multi-disc structure made up of multi-rotor and multi-stator in order to improve the torque. This multi-disc structure motor applies very well to robot and equipment of large torque direct drive. In the meanwhile, the axial size of disc motor is limited because of the structure. Too big radius increases the difficulty of processing technology. The Block Ceramic Magnets interrelated size of motor can not be assured. So multi-disc structure is always used in order to improve the output power of the motor.The development of permanent magnet machines tends to great power, high function and micromation at present. High power density and efficiency are the common requests to all the permanent magnet machines designing. This text introduces a new type of multi-disc coreless permanent magnet synchronous motor based on Halbach array to improve output power. The motor uses high coercive force characteristic of NdFeB permanent magnet material and high gathering magnetism function of Halbach array to improve airgap magnetic flux density in the motor.
　　This also makes coreless motor possible. Moreover, Halbach array can reduce magnetic flux in the yoke. So yoke iron can be less used or not used. This will greatly decrease the weight of the motor and also save the cost of the motor.As a new type of motor, there are many differences in structure and calculation method between disk coreless PMSM and common permanent magnet motor. Design theory of common permanent magnet motors can not be used directly. The structure and the characteristics of the motor using HALBACH array are also introduced. The FEM analysis has been done to build the mathematics model and study the magnetic field characteristics of the http://www.chinamagnets.biz/Ceramic/Block-Ceramic-Magnets.php motor. The text studies hot to choose Halbach array, optimizing air gap structure—wedgy air gap, choosing structure form of multi-disc permanent magnet motor-- unit motor combined structure, arrangement between unit motors. And finally the interrelated design parameters of permanent magnet and arrangement between unit motors are determined according to the results of the FEM analysis.The text sums up processing technology of disc coreless permanent magnet synchronous motor based on Halbach array, solves the problems of the whole/half axial machining technics, the inner/outer rotor structure technics, the fixation of the PMs, the rotor’s perfusion and so on.. And the special technics equipment for machining of the motor has been designed. Lastly, software for electromagnetism calculation is compiled.