The Research Of Decoupling Control Of Torque And Radial Force For Bearingless Switched Reluctance Motor

Switched reluctance motor(SRM)is the structure of double-salient-pole without any windings and permanent magnets on the rotor.It has advantages of simple structure and resilience to harsh operating conditions.The introduction of bearingless technology could fully take advantage of the high-speed ability of SRM.The current control algorithm of bearingless switched reluctance motor(BSRM)is complex due to the coupling of torque and radial force.It also has poor performance when dealing with the load mutation.In order to solve this problem,this paper mainly studied the decoupling control method of torque and radial force from two aspects of structure and control strategy in BSRMs.First of all,a structure of 12/4 single-winding bearingless switched reluctance motor(SWBSRM)which can realize natural decoupling of torque and radial force is studied through the design of motor structure.The working principle,control strategy and mathematical model are mainly expounded.ANSOFT modeling simulation is used to verify the validity of the mathematical model and decoupling characteristics.The MATLAB/SIMULINK modeling simulation is used to verify the feasibility of the structure in control.On the issue of lack of radial force in 12/4 SWBSRM when currents of torque and radial force given with different values,a structure of 12/4 dual-winding bearingless switched reluctance motor(DWBSRM)is studied.This structure not only reserve the decoupling characteristics of 12/4 SWBSRM,but also has the advantages of flexible control and low cost of controller.Simulation results show the superior performance of the proposed structure.Secondly,a direct instantaneous torque and direct force control strategy(DITC&DFC)is studied.The basic principle and working method is introduced mainly.This method can realize decoupling of the torque and radial force of BSRMs by making torque and radial force as variable to be contoroled directly.Meanwhile,it can effectively reduce the torque ripple and radial force ripple and simplify the current algorithm.Simulation and experimental results verify the validity of the decoupling characteristics of the proposed control strategy.Finally,in order to improve the reliability of BSRMs.Based on the DTC&DFC method of the 12/8 SWBSRM,the fault-tolerant control under short-circuit fault of windings is realized through analyzing the effect of short-circuit fault of windings and establishing the compensation principle and reconstructing the voltage vector.Experimental results verify the validity of the proposed fault-tolerant control strategy.