Study On Disk Coreless Permanent Magnet Synchronous Machine Based On PCB Technology

Disc permanent magnet synchronous machine is ironless axial flux permanent magnet(AFPM) machine. It has many advantages of high power density, high efficiency, simple and compact structure, significant quality reduction, smooth running at low speed and so on. The machine can use PMs arranged in Halbach array structure. An ideal sinusoidal distribution of magnetic flux density is obtained. In most cases, the windings are held together in position by using composite material of epoxy resin. This manufacturing process is not yet mature. The placement and positioning of coils are difficult. It is difficult to achieve the required coil shape and size. The mature printed circuit board(PCB) technology is introduced into the coreless winding manufacturing. The flat structure of PCB is very suitable for ironless axial flux permanent magnet machine which is axial magnetic structure. The desgin of PCB winding, air-gap magnetic field analysis, finite element method(FEM) and optimization design are studied in this paper.The structure characteristics of ironless AFPM machine based on PCB technology are analyzed. The machine consists of double rotor and one stator. PMs of the rotor are arranged as Halbach array. Coreless winding is PCB winding, which is fixed on the casing. It improves the technology of winding manufacturing and cooling capacity. The no-load electromagnetic field of ironless AFPM machine is studied by analytical method. The magnetic circuit at the average radius is the main magnetic circuit. The ironless AFPM machine is equivalent as the two-dimensional linear motor.The result of analytical method is same as the result of FEM.The design method of ironless AFPM machine based on PCB technology is proposed. The PCB winding is non-overlapping concentrated winding. The shape of coils has advantages of both trapezoidal shape and circular shape. The analytical calculation formula of no-load back-EMF of ironless AFPM machine based on PCB technology is deduced. The results of analytical method and FEM analysis are same.It can be a reference for parametric design of the machine. An ironless AFPM prototype is designed in detail. The method of determining the main dimensions, PCB winding and PM size parameters is given. The performance of the prototype is analyzed with 3D FEM.The paper proposes ironless AFPM machine with new type Halbach arrays. The cross-section of permanent magnet is like Chinese character ‘?'. Its magnetization is as same as 90 ° Halbach arrays. Parameters of ironless AFPM machine is optimized based on taguchi method. The sine distribution of air-gap magnetic field is obtained.PCB winding of ironless AFPM motor based on PCB technology is optimized. The parameters of PCB winding is analyzed such as radial length, the incline of effective edge, center of the coil to improve the ratio of torque and copper loss ratio. The optimal of coil shape is obtained.