The bearingless induction motor, which combines the inductionmotor and magnetic bearing is a strongly coupled complicatednonlinear system; the decoupling control of the electromag- net toqueand readial levitation forc...The bearingless induction motor, which combines the inductionmotor and magnetic bearing is a strongly coupled complicatednonlinear system; the decoupling control of the electromag- net toqueand readial levitation force is the base of the stable operation ofthe benaringless motor. In this paper, the air-gap motor fluxoriented vector control is proposed to realize the decoupling controlof this nonlinear system even in the transient case based on thelevitation principle. Simulations show the stable suspension and goodperformance of the proposed algorithm.展开更多
Applications are limited at present because the currently available ultrasonic motors (USMs) do not provide suffi-ciently high torque and power. The conventional travelling-wave USM needs the bearing to support, which...Applications are limited at present because the currently available ultrasonic motors (USMs) do not provide suffi-ciently high torque and power. The conventional travelling-wave USM needs the bearing to support, which required lubricant. To solve the above problem, a bearingless travelling-wave USM is designed. First, a novel structure of the two-sided USM consisting of a two-sided teeth stator and two disk-type rotors is designed. And the excitation principle of the two-sided travelling-wave USM is analyzed. Then, using ANSYS software, we set up the model of the stator to predict the excitation frequency and modal response of the stator. The shape of the vibration mode was obtained. Last, the load characteristics of the USM are measured using ex-perimental method. The maximum stall torque and the no-load speed were obtained. The results showed that the characteristics of the two-sided USM are better than those of the conventional one-sided USM.展开更多
This paper addresses the bearingless motor with a single set of multiphase windings. The interaction between M and M±1 pole-pair magnetic fields produces radial force. Based on this principle,a bearingless machin...This paper addresses the bearingless motor with a single set of multiphase windings. The interaction between M and M±1 pole-pair magnetic fields produces radial force. Based on this principle,a bearingless machine is obtained. Conventional bearingless machine has dual windings,levitation windings and torque windings,which produce the two magnetic fields. In the proposed bearingless motor,the two needed magnetic fields are produced by feeding two groups of currents to a single set of multiphase windings. Taking a 5-phase induction motor as example,the inductance matrices,considering air gap eccentricity,are calculated with the modified winding function method. The radial force analytical model is deduced by virtual displacement,and its results are validated by FEA. The mathematical model of the new bearingless machine is set up,and the simulation results verified the feasibility of this novel bearingless motor.展开更多
According to the structural characteristics of embedded fluid elastomeric damper and dynamic modeling method of bearingless rotor(BR)system,a time-domain dynamic model based on multilayer elastomeric theory and fluid ...According to the structural characteristics of embedded fluid elastomeric damper and dynamic modeling method of bearingless rotor(BR)system,a time-domain dynamic model based on multilayer elastomeric theory and fluid dynamic equations is developed.The parameters contained in the analysis model are identified by dynamic experiment data of embedded fluid elastomeric damper.The dynamic characteristics curves calculated through dynamic model are compared with those derived from experimental data.The consistent results illustrate that the model can describe the nonlinear relationship between stress and strain of embedded fluid elastomeric damper under different displacement amplitude and frequency.Due to the validity and reliability of the dynamic analysis model,it can be used in aeroelastic characteristics calculation of BR with embedded fluid elastomeric damper for helicopters.展开更多
Bearingless switched reluctance motor(BSRM) not only combines the merits of bearingless motor(BM) and switched reluctance motor(SRM), but also decreases the vibration and acoustic noise of SRM, so it could be a strong...Bearingless switched reluctance motor(BSRM) not only combines the merits of bearingless motor(BM) and switched reluctance motor(SRM), but also decreases the vibration and acoustic noise of SRM, so it could be a strong candidate for high-speed driving fields. Under the circumstances, a 12/14 BSRM with hybrid stator pole has been proposed due to its high output torque density and excellent decoupling characteristics between torque and suspension force. However, this motor has torque dead-zone, which leads to problems of self-start at some rotor positions and large torque ripple during normal operation. To solve the existing problems in the 12/14 type, an asymmetric rotor pole type BSRM is proposed. The structure and design process of the proposed motor is presented in detail. The characteristics of the proposed motor is analyzed and compared with that of the 12/14 type. Furthermore, prototype of the proposed structure is designed, manufactured and experimented. Finally, simulation and test results are illustrated and analyzed to prove the validity of the proposed structure.展开更多
Although the five-degree-of-freedom magnetic levitation system composed of two conical bearingless switched reluctance motors(CBSRMs)owns the simplest structure,the torque and levitation forces are coupled greatly.The...Although the five-degree-of-freedom magnetic levitation system composed of two conical bearingless switched reluctance motors(CBSRMs)owns the simplest structure,the torque and levitation forces are coupled greatly.Therefore,it is difficult to make the rotor rotate and be fully levitated simultaneously.To solve this problem,two different role division control strategies are proposed in this paper,i.e.individual role division and mutual role division control strategies.The difference between them is the selection of motor which controls the torque or the axial force.In order to understand the characteristics of control variables,the principle and mathematical model of CBSRM are introduced.After that,two control strategies are explained in detail.To verify the demonstrated performance,the simulations are completed with MATLAB/Simulink.展开更多
Different from conventional switched reluctance motor(SRM),bearingless SRM not only provides torque but also supplies levitation force for free-friction of rotor.In order to make sure that bearingless SRM can steadily...Different from conventional switched reluctance motor(SRM),bearingless SRM not only provides torque but also supplies levitation force for free-friction of rotor.In order to make sure that bearingless SRM can steadily levitates in static and dynamic rotating operation,it is necessary to analyze suspending force.Therefore,suspending force performance of an improved bearingless SRM with permanent magnets in stator yoke is comprehensively investigated in this paper.Basic structure and operation principle with permanent magnets in stator yoke are introduced firstly.Furthermore,mathematical model is built up for design of suspending force.In addition,parametric analysis for levitation performance is implemented.Finally,validity of proposed method is verified by experimental results.展开更多
A 5-degrees-of-freedom bearingless induction motor is a multi-variable,nonlinear and strong-coupled system．In order to achieve rotor suspension and operation steadily,it is necessary to realize dynamic decoupling con...A 5-degrees-of-freedom bearingless induction motor is a multi-variable,nonlinear and strong-coupled system．In order to achieve rotor suspension and operation steadily,it is necessary to realize dynamic decoupling control among torque and suspension forces．In the paper,a method based on α-th order inverse system theory is used to study dynamic decoupling control．Firstly,the working principles of a 3-degrees-of-freedom magnetic bearing and a 2-degrees-of-freedom bearinglees induction motor are analyzed, the radial-axial force equations of 3-degrees-of-freedom magnetic bearing,the electromagnetic torque equation and radial force equations of the 2-degrees-of-freedom bearingless induction motor are given,and then the state equations of the 5-degrees-of-freedom bearingless induction motor are set up．Secondly,the feasibility of decoupling control based on dynamic inverse theory is discussed in detail,and the state feedback linearization method is used to decouple and linearize the system．Finally,linear control system techniques are applied to these linearization subsystems to synthesize and simulate．The simulation results have shown that this kind of control strategy can realize dynamic decoupling control among torque and suspension forces of the 5-degrees-of-freedom bearingless induction motor,and that the control system has good dynamic and static performance．展开更多
Dynamic stability equations of bearingless rotor blades were investigated using a simplified model.The aerodynamic loads of blades were evaluated using two-dimensional airfoil theory.Perturbation equations were obtain...Dynamic stability equations of bearingless rotor blades were investigated using a simplified model.The aerodynamic loads of blades were evaluated using two-dimensional airfoil theory.Perturbation equations were obtained by linearization of the perturbation.A normal-mode approach was used to transform the equations expressed by nodal degrees of freedom into equations expressed by modal degrees of freedom,which can reduce the dimension of the equations.The stability results of rotor blades were presented using eigenvalue analysis.The shape function matrix was obtained using spline interpolation,which simplified the analysis and made assembly of the inertial matrix,damping matrix,and stiffness matrix a simple mathematical summation.The results indicate that the method is efficient and greatly simplifies the analysis.展开更多
A bearingless permanent magnet synchronous motor(BPMSM)has two sets of stator windings,torque windings and suspension force windings.By analyzing the flux linkage intersection between the two sets of windings,a method...A bearingless permanent magnet synchronous motor(BPMSM)has two sets of stator windings,torque windings and suspension force windings.By analyzing the flux linkage intersection between the two sets of windings,a method of transforming mechanical coordinates to electrical coordinates is put forward.According to this method,flux linkage equations and voltage equations of the two stator windings are derived.The electromagnetic torque equation of the BPMSM is derived based on the analysis of the role of Lorentz force in the BPMSM.After analyzing the mathematical formula of various sort radial forces in the BPMSM,a complete function of radial suspension forces for the BPMSM is obtained.Finally,an experimental system control diagram and some test results are discussed.This mathematical model provides a theoretical foundation for BPMSM simulation study,experiment waveform analysis and structure design.展开更多
文摘The bearingless induction motor, which combines the inductionmotor and magnetic bearing is a strongly coupled complicatednonlinear system; the decoupling control of the electromag- net toqueand readial levitation force is the base of the stable operation ofthe benaringless motor. In this paper, the air-gap motor fluxoriented vector control is proposed to realize the decoupling controlof this nonlinear system even in the transient case based on thelevitation principle. Simulations show the stable suspension and goodperformance of the proposed algorithm.
基金Project (No. 50175018) supported by the National Natural ScienceFoundation of China
文摘Applications are limited at present because the currently available ultrasonic motors (USMs) do not provide suffi-ciently high torque and power. The conventional travelling-wave USM needs the bearing to support, which required lubricant. To solve the above problem, a bearingless travelling-wave USM is designed. First, a novel structure of the two-sided USM consisting of a two-sided teeth stator and two disk-type rotors is designed. And the excitation principle of the two-sided travelling-wave USM is analyzed. Then, using ANSYS software, we set up the model of the stator to predict the excitation frequency and modal response of the stator. The shape of the vibration mode was obtained. Last, the load characteristics of the USM are measured using ex-perimental method. The maximum stall torque and the no-load speed were obtained. The results showed that the characteristics of the two-sided USM are better than those of the conventional one-sided USM.
基金Project (No. 50677060) supported by the National Natural ScienceFoundation of China
文摘This paper addresses the bearingless motor with a single set of multiphase windings. The interaction between M and M±1 pole-pair magnetic fields produces radial force. Based on this principle,a bearingless machine is obtained. Conventional bearingless machine has dual windings,levitation windings and torque windings,which produce the two magnetic fields. In the proposed bearingless motor,the two needed magnetic fields are produced by feeding two groups of currents to a single set of multiphase windings. Taking a 5-phase induction motor as example,the inductance matrices,considering air gap eccentricity,are calculated with the modified winding function method. The radial force analytical model is deduced by virtual displacement,and its results are validated by FEA. The mathematical model of the new bearingless machine is set up,and the simulation results verified the feasibility of this novel bearingless motor.
文摘According to the structural characteristics of embedded fluid elastomeric damper and dynamic modeling method of bearingless rotor(BR)system,a time-domain dynamic model based on multilayer elastomeric theory and fluid dynamic equations is developed.The parameters contained in the analysis model are identified by dynamic experiment data of embedded fluid elastomeric damper.The dynamic characteristics curves calculated through dynamic model are compared with those derived from experimental data.The consistent results illustrate that the model can describe the nonlinear relationship between stress and strain of embedded fluid elastomeric damper under different displacement amplitude and frequency.Due to the validity and reliability of the dynamic analysis model,it can be used in aeroelastic characteristics calculation of BR with embedded fluid elastomeric damper for helicopters.
基金supported by National Natural Science Foundation of China under Grant 52077141 and 51920105011Young and Middle-Aged Scientific and Technological Innovation Talent Program of Shenyang City of Liaoning Province of China under Grant RC200427。
文摘Bearingless switched reluctance motor(BSRM) not only combines the merits of bearingless motor(BM) and switched reluctance motor(SRM), but also decreases the vibration and acoustic noise of SRM, so it could be a strong candidate for high-speed driving fields. Under the circumstances, a 12/14 BSRM with hybrid stator pole has been proposed due to its high output torque density and excellent decoupling characteristics between torque and suspension force. However, this motor has torque dead-zone, which leads to problems of self-start at some rotor positions and large torque ripple during normal operation. To solve the existing problems in the 12/14 type, an asymmetric rotor pole type BSRM is proposed. The structure and design process of the proposed motor is presented in detail. The characteristics of the proposed motor is analyzed and compared with that of the 12/14 type. Furthermore, prototype of the proposed structure is designed, manufactured and experimented. Finally, simulation and test results are illustrated and analyzed to prove the validity of the proposed structure.
基金supported by the National Natural Science Foundations of China (Nos. 51877107,51577087,51477074)
文摘Although the five-degree-of-freedom magnetic levitation system composed of two conical bearingless switched reluctance motors(CBSRMs)owns the simplest structure,the torque and levitation forces are coupled greatly.Therefore,it is difficult to make the rotor rotate and be fully levitated simultaneously.To solve this problem,two different role division control strategies are proposed in this paper,i.e.individual role division and mutual role division control strategies.The difference between them is the selection of motor which controls the torque or the axial force.In order to understand the characteristics of control variables,the principle and mathematical model of CBSRM are introduced.After that,two control strategies are explained in detail.To verify the demonstrated performance,the simulations are completed with MATLAB/Simulink.
基金This work was supported by the National Natural Science Foundation of China under Grant 51777004.
文摘Different from conventional switched reluctance motor(SRM),bearingless SRM not only provides torque but also supplies levitation force for free-friction of rotor.In order to make sure that bearingless SRM can steadily levitates in static and dynamic rotating operation,it is necessary to analyze suspending force.Therefore,suspending force performance of an improved bearingless SRM with permanent magnets in stator yoke is comprehensively investigated in this paper.Basic structure and operation principle with permanent magnets in stator yoke are introduced firstly.Furthermore,mathematical model is built up for design of suspending force.In addition,parametric analysis for levitation performance is implemented.Finally,validity of proposed method is verified by experimental results.
基金Supported by National Natural Science Foundation of P.R.China(50575099,60674095)
文摘A 5-degrees-of-freedom bearingless induction motor is a multi-variable,nonlinear and strong-coupled system．In order to achieve rotor suspension and operation steadily,it is necessary to realize dynamic decoupling control among torque and suspension forces．In the paper,a method based on α-th order inverse system theory is used to study dynamic decoupling control．Firstly,the working principles of a 3-degrees-of-freedom magnetic bearing and a 2-degrees-of-freedom bearinglees induction motor are analyzed, the radial-axial force equations of 3-degrees-of-freedom magnetic bearing,the electromagnetic torque equation and radial force equations of the 2-degrees-of-freedom bearingless induction motor are given,and then the state equations of the 5-degrees-of-freedom bearingless induction motor are set up．Secondly,the feasibility of decoupling control based on dynamic inverse theory is discussed in detail,and the state feedback linearization method is used to decouple and linearize the system．Finally,linear control system techniques are applied to these linearization subsystems to synthesize and simulate．The simulation results have shown that this kind of control strategy can realize dynamic decoupling control among torque and suspension forces of the 5-degrees-of-freedom bearingless induction motor,and that the control system has good dynamic and static performance．
基金National Hi-tech Research and Development Program of China(2012AA112201)National Natural Science Foundation of China(10772013)+1 种基金The Fundamental Research Funds for the Central UniversitiesAeronautical Science Foundation of China(20100251007)
文摘Dynamic stability equations of bearingless rotor blades were investigated using a simplified model.The aerodynamic loads of blades were evaluated using two-dimensional airfoil theory.Perturbation equations were obtained by linearization of the perturbation.A normal-mode approach was used to transform the equations expressed by nodal degrees of freedom into equations expressed by modal degrees of freedom,which can reduce the dimension of the equations.The stability results of rotor blades were presented using eigenvalue analysis.The shape function matrix was obtained using spline interpolation,which simplified the analysis and made assembly of the inertial matrix,damping matrix,and stiffness matrix a simple mathematical summation.The results indicate that the method is efficient and greatly simplifies the analysis.
基金Supported by the National Hi-Tech Research and Development Program of China("863"Project)(Grant No.2007AA04Z213)
文摘A bearingless permanent magnet synchronous motor(BPMSM)has two sets of stator windings,torque windings and suspension force windings.By analyzing the flux linkage intersection between the two sets of windings,a method of transforming mechanical coordinates to electrical coordinates is put forward.According to this method,flux linkage equations and voltage equations of the two stator windings are derived.The electromagnetic torque equation of the BPMSM is derived based on the analysis of the role of Lorentz force in the BPMSM.After analyzing the mathematical formula of various sort radial forces in the BPMSM,a complete function of radial suspension forces for the BPMSM is obtained.Finally,an experimental system control diagram and some test results are discussed.This mathematical model provides a theoretical foundation for BPMSM simulation study,experiment waveform analysis and structure design.
