Torque And Eddy Current Loss Of Outer Stator Magnetic Gear Integrated Permanent Magnet Motor

In the fields of modern industrial automation,wind power generation and new energy,the features of low speed and large torque are required by the motors.Otherwise,a large gear reduction mechanism is needed to match the speed and torque between the motor and the load.The efficiency and reliability of the motor system are poor.Magnetic gears are based on the principle of magnetic field modulation,so that all permanent magnets are involved in transmitting torque,making their torque density and efficiency high.Combining the magnetic gear and the permanent magnet synchronous motor,the magnetic gear composite motor has improved the torque density and efficiency by using the magnetic gear as the transmission device,which has wide application prospects.The topology and principle of the magnetic gear and the outer stator magnetic gear integrated permanent magnet motor are analyzed.The finite element simulation model and mathematical model of the outer stator magnetic gear integrated permanent magnet motor is established and the electromagnetic simulation analysis is carried out.The influence of the parameters of the magnetic flux ring on the electromagnetic torque on the outer rotor of the magnetic flux ring is analyzed by finite element simulation,and the best width of the magnetic conductive block in the magnetic flux ring is determined.By setting the imaginary coils at the stator permanent magnet boundary in different magnetization directions and the inner and outer air gap sides of each non-magnetic block in the magnetic flux ring,the variation of the flux linkage of the imaginary coil when the motor is under no load and load are obtained by simulation analysis.Further,the induced electromotive force and the possible eddy current loss in the non-magnetic block in each permanent magnet and magnetic flux ring are obtained.The loss of each component in the motor obtained by simulation shows that the eddy current loss of the outer stator magnetic gear integrated permanent magnet motor is mainly concentrated in all the permanent magnets and the magnetic flux regulating ring components.The 2D finite element simulation method is used to analyze the change trend of eddy current loss when the permanent magnet magnetic circuit of high-speed permanent magnet inner rotor adopts surface convex rotor structure,surface insert rotor structure and built-in rotor magnetic circuit structure.The analysis shows that the surface insert rotor structure of the rotor magnetic circuit structure can effectively reduce the eddy current loss of the high-speed permanent magnet inner rotor permanent magnet,but at the same time,the output torque of the motor is reduced.