Shape Design Of Windings Of Disc-type Permanent Magnet Synchronous Machine With PCB Stator

As an electrical machine with high performance and special construction,disctype synchronous electrical machine is widely used in fields such as aviation,military,agricultural and industrial production and daily life.It has many advantages such as light weight,small size and compact structure.In this paper,printed circuit board(PCB)is used for stator construction.On the one hand,it eliminates the stator iron core so that the cogging torque can be reduced and the starting resistance torque can be decreased.On the other hand,it simplifies the processing technic of stator production and increases the accuracy of the product.So that the mass production will be easier to achieve and the conformity of the product will be better.Electrical field calculation is an indispensable process in design and performance prediction of electrical machine.Different from traditional radial flux electrical machine,disc-type electrical machine is a kind of axial flux electrical machine.That makes it difficult for disc-type electrical machine to simplify the three-dimensional electromagnetic field analyzation down to two-dimensional analyzation.It is the same for the winding analysis.We need other analytical methods.In this paper,the structure of axial flux electrical machine with one stator between two rotors is firstly introduced.Halbach array is used in this machine.The distribution of magnetic field and the parameters of the main magnetic circuit are analyzed on the basic of magnetic circuit model.Winding factor is calculated afterwards.It is practical to divide the wires in the radial direction,calculate the winding factor of each element and reach the overall winding factor by integration because of the accuracy of PCB production and the limited number of turns.Comparison among three traditional shapes of windings,circle,rhombus and trapezoid is mentioned in the paper based on that analytical model.New type of shape is designed which combines the advantages of the circle shape and the trapezoid shape.Higher electromotive force is acquired under the premise of shorter coil head.Lower copper loss and higher current density can be guaranteed.Finite element models of four shapes are built so that the result of the analyzation can be verified.Prototype machine is made to verify the conclusion.The electrical machine worked as generator in the experiment and parameters such as noload electromotive force are measured in the experiment.