Research On Improving Power Density Of Axial Flux Generator For Small-scale Wind Power Application

As for a new energy power generation industry,Wind power generation has advantages of environmental friendly,economical benefits,high efficiency,flexible investment among other new energy which can't be achieved.Small off-grid wind power system has the feature of small output power,high natural environment adaptiveness,and high reliability which is widely used in remote area.When step into 21st century,scholars around the world did plenty of deep research around tombarthite permanent magnet materials especially Nd-Fe-B permanent magnet materials which accelerate the development of permanent magnet motor.Due to the application of tombarthite permanent material in the disk type permanent magnet motor,so it is suitable for small size vertical axial wind power generation system with the merit of small volume,light weight,extended service life,great heat dissipation,and few noise.The goal of this article is to design and produce a kind of applicable to small vertical axis wind turbine disc generator,and optimization of the generator,improve the power density of the machine.The specific work includes(1)set the goal of improving the efficiency of disc permanent magnet generator which is used in small vertical axis wind turbine.In order to accomplish this goal,we choose intermediate stator disc generator as the ideal disc generator used in small vertical axis wind turbine among different disk motor structures.(2)the advantages and application of halbach magnetization structure have been briefly introduced and the basic electromagnetic relation of disk motor has been derived.(3)Although we can use graphic method,simulation method and analytic method to solve the problem of disk motor magnetic field,Ansoft Maxwell method are more precise,simple and convenient among other solution in the term of calculation.As a Consequence,control variable method was adopted base on the Ansoft Maxwell method to optimize the shape,thickness,air gap,and other parameters of magnetic pole.(4)After the optimization design of the motor,along with the analyze of Maxwell 3D transient simulation of no load voltage and load power,we prove the final output voltage,current and power through electricity experiment.However,the plate-type generator with no iron core and halbach structure has a small axial dimension,high power density and simple structure in the field of direct drive wind power.The magnetic pole adopts special halbach structure,which makes the density of air gap more sinusoidal and avoids the added loss of the harmonic.(5)We have proved that disk magnetic motors with halbach array have better significantly effect in improving the power density of motors than normal disk magnetic motors by comparing output voltage,current and power.Disk generator craftsmanship is an crucial part.The armature plate production and screens of the pole are very difficult?The production making process of disk motors and some notes are mentioned afterwards.Experiments showed good performance with the halbach magnetic pole structure disk motors by improving the efficiency of generate power and it showed the same when applied in the small vertical shaft wind turbines.