| Flux-switching permanent magnetic motor(FSPMM),which has the permanent magnet embedded in the stator,gets more and more widespread concern in recent years because of the advantages of good permanent magnet cooling conditions and simple rotor structure.The application of bearingless technology in this type of motor can form a new type of motor structure,that is,the bearingless flux switching permanent magnetic motor(BFSPMM).BFSPMM has unique advantages and application value in the fields of high temperature or the single use of rotors,such as cleaning,medical and health products.Firstly,the paper introduces the basic structure of a typical 12/10 FSPMM and analyzes its working principle and static characteristics.A three-phase suspension winding is constructed on the topology of classic 12/10 FSPMM with three-phase power winding according to the idea that the space symmetrical air-gap magnetic fields can be modulated in opposite direction with space symmetrical coils.Finally,a double winding BFSPMM with three-phase power winding and three-phase suspension winding is formed.In order to overcome the shortcomings of finite element analysis time consuming and taking up computing resources,this paper research on the magnetic circuit network analysis of BFSPMM,including the rotor in a non-eccentric state and the rotor in an eccentric state.An automatic method of magnetic circuit segmentation by programming is proposed for the non-eccentric state of BFSPMM.Based on this method,the automatic division and the calculation of the magnetic circuit are realized.In order to further consider the dynamic eccentric state during the actual operation of the rotor and the need to calculate the suspension force,a method of magnetic network analysis of BFSPMM considering rotor eccentricity is proposed,and based on this method,the magnetic circuit analysis under rotor eccentricity is realized.The correctness of the magnetic circuit analysis in the non-eccentric state and in the eccentric state are verified by comparing with the results of finite element,which provides a means for the rapid design or initial stage parameter determination and performance analysis of this type motor.This paper deduces the mathematical model of the suspension force based on the Maxwell’s tensor method and establishes the mathematical model of the motor tangential rotation control.On the basis of these,a driving control strategy without rotor position angle in suspension control is proposed to further reduce the dependence of suspension control on rotor position angle information and improve the reliability.The two sets of winding are supplied by three-phase inverters respectively.The three-phase suspension forces,produced by positive current passing through the three-phase winding respectively,are spaced by 120 degrees,and thus the demanded suspension force is synthesized by the three-phase suspension force.The rotation of rotor is controlled by power winding with vector control.The results of theory analysis and experiments show that the rotor can be suspended around the center and the tangential rotation of the motor has little effect on the stable rotor suspension control. |
