Study on Electromagnetic Design and Control Strategy Simulation for Bearingless Permanent Magnet-type Synchronous Motor

　　Study on Electromagnetic Design and Control Strategy Simulation for Bearingless Permanent Magnet-type Synchronous Motor
　　A bearingless permanent magnet-type synchronous motor(BPMSM) is a novel motor, in which the levitation winding for levitation force is embedded in armature core. Its rotor can product both rotating torque and levitation force. The permanent magnet synchronous motor has the merits of high power, long life, high efficiency and small volume. Ball Neodymium Magnets With the advantage of bearingless, the BPMSM has expended the application field of high-speed motor in micromation and high power range. Its unique levitation mechanism and structural characteristics made it more economic and technology advantages than traditional motors in some high technology field, and it has widely application foreground.This dissertation is devoted to mathematics model establishment and electromagnetic design of the BMPSM, including proposing a feasible control strategy. The concrete content is as follow:Firstly, based on the fundamental principle of the bearingless and producing radial suspension forces in BPMSM, the levitation force mathematic model of BPMSM is deduced. Study on the influence factors and its influence laws of levitation force using finite element method(FEM). Make verification and correction of the levitation force model, which produce a accurate levitation force http://www.chinamagnets.biz/Neodymium/Ball-Neodymium-Magnets.php mathematic model.Secondly, based on the levitation force modal and FEM analysis, the relationships between levitation force and permanent magnet thickness, air-gap length in a surface permanent magnet synchronous bearingless motor are found. A electromagnetic design method is proposed, which can complete the electromagnetic design considering both levitation force and torque requirement. The validity of this design is verifiede by FEM.Finally, based on the models of electromagnetic torque and levitation force, a i1 d =0 rotor field oriented torque control and a direct control for rotor eccentric displacement levitation force control strategy are applied. The control system is constructed using Matlab/Simulink toolbox. The operation performances are simulated. Simulation results have shown that this control strategy realizes direct control for rotor eccentric displacement.