| Bearingless Switched Reluctance Motor(BSRM)integrates SRM with magnetic bearing to integrate the rotating function and stable suspension function,with advantages such as low power consumption,simple structure,long service life and high critical speed.It has been widely used in industrial production,aerospace and medical and health fields,and has a good prospect.However,due to the short time of BSRM,there are still many problems such as control coupling to be solved.Firstly,aiming at the control coupling problem between torque and suspension force of traditional BSRM,the root cause of the control coupling problem between torque and suspension force is analyzed.Improved the structure of BSRM from the perspective of short circuit excitation and independent control of torque and suspension force,a new 16 phase BSRM which can realized decoupling control between torque and suspension force was proposed,.its’ machenical structure,rotation principle and suspension principle is described.According to the design principle of BSRM,the specific structural parameters are given.Secondly,the 2D model of the new 16 phase BSRM was built in the finite element simulation software Ansys Maxwell,the basic performance such as inductance,torque and suspension force was analysied and simulated,and the decoupling performance was proved by the decoupling degree of flux linkage and the effect degree of suspension winding current on the output torque.Compaired the performance with the existed decoupling structure such as 12/14 BSRM and 12/4 BSRM,the advantages and disadvantages of the new 16 phase BSRM are obtained:the torque ripple and suspension force fluctuation of the new 16 phase BSRM are smaller,its’ operation stability and decoupling effect is obviously better than the other two,but the torque regulation ability and suspension force regulation ability are weaker.Then,the air gap between the stator and rotor is separated based on the straight line and elliptic magnetic circuit segmentation method.The expression of the air gap thickness between the stator and rotor is solved,and the expression of air gap permeability is simplified by the coordinate transformation method.The equivalent magnetic circuit model is established,and the expression of winding energy storage about winding inductance is obtained,then the mathematical model of torque and suspension force of the new 16 phase BSRM is obtained by using the virtual displacement theorem.The correctness of the mathematical model is verified by the finite element simulation results.Finally,according to the structure characteristics and application situation of the new 16 phase BSRM,the control strategy of mean torque and instantaneous suspension force are selected,and obtained the control current expression of torque winding and suspension windings under ideal condition.The verification by Ansys Maxwell 2D shows that under the ideal condition,when the torque winding current is 0.5A and 1A respectively,the realitive error of average torque is 2.5%and 1%respectively,and the suspension force fluctuates within±0.75N.To simulate the actual running condition of the rotation system,the circuit of rotation system was established by Ansys Maxwell Circuit Editor,and according to the simulasion results,the control current expression of torque winding was improved.The startup and speed regulation performance without load torque,the startup performance with different load torque and the speed regulation performance with constant load torque were analysied and simulated,and the results show that when considering the effect of the circuit,the improved control current expression of torque winding can control the startup and speed more accurately. |
PDF Full Text Request