Research On Electromagnetic Field Of Outer Rotor Permanent Magnet Wind Turbine Generator Based On Halbach Array

Halbach array is new arrangement which is combination of horizontal direction and vertical direction magnetizing with alternate arrangement.The Halbach array has a better magnetic effect,so that the unilateral magnetic flux is strengthened,Thus,it is possible that the rotor yoke is made of non-magnetic material,which can reduce the weight of the motor.The sinusoidal property of air gap flux density is better,The air gap flux density waveform is improved without the technology of rotor-Skewing or Skew-slot.Which can effectively reduce the manufacturing costs and installation difficulty,and obtain better power density and high efficiency.Reduce cogging torque and reduce the motor noise and oscillation.Duo to the above characteristics of Halbach array,some developed countries have introduced Halbach arrays in various fields.However,in the field of wind turbines,the use of Halbach array permanent magnet motor is rare,especially in the megawatt level permanent magnet wind power generator has not been used.Therefore,this paper designs a megawatt level permanent magnet wind power generator based on Halbach array,and studies the influence of the new array on the performance of megawatt level permanent magnet wind power generator.In this paper,the 1.5MW permanent magnet wind power generator based on Halbach array is studied.Firstly,the model of 1.5MW traditional array permanent magnet wind power generator is established by using software-RMxprt,the parameters of the model are analyzed and the reasonable parameters of the motor are determined.Secondly,according to the motor parameters determined by software-RMxprt,The model of 1.5MW permanent magnet wind power generator is established by Ansoft/Maxwell finite element simulation software.Static state analyzed Three kind of magnetizing methods and Three kind of permanent magnet structures,When the rotor yoke is a magnetic and non-magnetic material,obtain the air gap magnetic flux density and each harmonic content.The optimization scheme of permanent magnet is put forward.The no-load operation characteristics of the traditional array and Halbach array permanent magnet wind power generator are compared by Maxwell2 D software and external circuit coupling method,and thesuperiority of Halbach array is verified.In the end,the load characteristics of the Halbach array permanent magnet wind power generator and the occurrence of various sudden short circuit faults are simulated.The maximum short-circuit condition and maximum short circuit was obtained.Combined NdFeB permanent magnent high temperature demagnetization curve and the maximum short-circuit current of the permanent magnetic wind power generator when occurs three phase short circuit,single phase short circuit and phase short circuit fault,The demagnetization ability of permanent magnet is checked.The magnetic flux density of the permanent magnetic was obtained,which is serious demagnetization.It is verified the Halbach array permanent magnetic wind power generator won't occur irreversible demagnetization in serious condition.