Design of multi-layer PCB coreless axial permanent magnet synchronous motor

The disc type coreless motor has the advantages of small armature reaction, linear parameter, no cogging torque and the like. In this paper, an axial magnetic field permanent magnet synchronous motor (AFPMSM) with three-rotor and two-stator structure with multi-layer PCB windings is presented. The structure and advantages of the motor are described, and the electromagnetic torque of the motor is analyzed. The conclusion is drawn by means of analytical method. When the amount of permanent magnet (PM) mass and the size of motor are the same, increasing the electromagnetic torque can also be converted to increasing the amplitude of air gap magnetic density (AGMD) fundamental wave. In this paper, to improve the fundamental amplitude and waveform sinusoidal of air gap flux density(AGFD), the PCB winding, motor size and rotor structure are optimized by the use of 3-D finite element analysis (FEA). The correctness and effectiveness of the designed motor are verified by the results of prototype experiment and finite element analysis.