Time Stepping Analytical Research Of The Steady Magnetic Field For The Surface-mounted Bearingless Permanent Magnet Motor

On the basis of the "basic research on the time-stepping analytical method of the transient magnetic field for the surface-mounted bearingless permanent magnet motor"(science and technology plan project by colleges and universities in Shandong province,project number:J16LN28),the research is aimed to establish the time-stepping analytical model of the transient magnetic field for the surface-mounted bearingless permanent magnet motor and solve,thereby enriching and perfecting the basic theoretical research system of the motor.The magnetic field of the surface-mounted bearingless permanent magnet motor is calculated and analyzed with the time-stepping analytical method in this paper based on the theory of electromagnetic field,and the main research contents are as follows:(1)The system equation is deduced by the time-stepping analytical method,and the system analytical model of the surface-mounted bearingless permanent magnet motor is established.Then the solution region is subdivided into the air gap region,the permanent magnet region and the groove region with the established vector magnetic potential equation for three regions.Combined with the boundary conditions,the general solution of the equation set is obtained through the separation variable method.Finally,the results of air gap magnetic density distribution in the corresponding state are got through the matlab programming simulation for further analysis.(2)The waveform of winding flux is calculated using the vector magnetic potential to get the flux linkage function,and the counter EMF is calculated by the flux linkage differential method.At the same time,the cogging torque of the bearingless permanent magnet motor is calculated by the Maxwell tensor method,which will be compared with the results of the finite element to verify validity and correctness of the algorithm.And then a theoretical analysis is carried out for the performance of the motor according to results.(3)A set of suspension windings is embedded into the stator slot of the motor so that the rotor is suspended relying on the resulting levitation force.Meanwhile,the levitation force generated by the suspension loading is analyzed,whose results will be compared with the finite element results.(4)After the analysis of the motor by the field-coupled time-step analytical method,the stator-circuit model and the voltage balance equation are constructed.At the same time,two given different methods of analyzing terminal voltage and load in field-coupled steady-state are analyzed to select an appropriate one for the later calculation and analysis.(5)The control platform of the motor is set up to conduct the experimental study on the motor,and then experimental results and simulation results of the counter EMF are compared.Finally,the effect of the suspension performance of the motor and the levitation force generated by the suspension winding load on the motor performance are tested.