Induction motors installation operation generators maintenance. Motor speed relationship the synchronous speed of an ac motor is the speed of the rotating magnetic field set up by the stator winding synchronous speed rpm 120 x frequency divided by the number of poles. Integrated solutions that leverage the motors magnetic field to create magnetic bearing forces on the shaft eliminate the need for radial bearings and source of friction, energy losses and oil migration. Aiming at the unbalanced vibration problem of bearingless induction motor caused by the rotor mass eccentricity, an adaptive lms extraction method of unbalanced displacement is proposed. Bearingless induction motors combining functions of both torque generation and noncontact magnetic suspension together have attracted more and more attention in the past decades due to their definite advantages of compactness, simple structure, less maintenance, no wear particles, high rotational speed, and so forth. To simplify the mathematical model of bearingless induction motor, rotor ux orientation and inverse system method have been adoptedin. Stator flux orientation inverse system decoupling control. Author links open overlay panel ke li a guoyu cheng a xiaodong sun b zebin yang a yeman fan c. Recently, aiming at some kind of bearingless motor, research has been conducted on sensorless technology and unbalance vibration control technology 4,10,11. When receiving a motor with oil mist lubricated antifriction bearings. According to the strong coupling between the electromagnetic torque and radial suspension force, and the difficulty of establishing a precise mathematical model of bearingless induction motor, least squares support vector machine is proposed in this paper.
Converts the windings current in the xy coordinate system to e q d coordinate system, as shown in equation 9. Eccentricity detection is an important topic in motor fault diagnosis and bearingless motor controls. Unbalanced displacement lms extraction algorithm and. Diaplacement sensorless control strategy of bearingless. A bearingless motor is an integrated device that possesses magnetic bearing capability in addition to having the torqueproducing function. Bearingless motor unit three spatial degrees of freedom of the rotor, rotation and radial position are stabilized actively by electronically controlled magnetic fields.
The oil mist lubrication should be in operation within two weeks after the motor is received from the factory. In the experiments, stable magnetic suspension and speed regulations are confirmed. In order to improve its dynamic control performance, considering the stator current dynamics, a stator flux orientation sfo inverse system decoupling control strategy is proposed in this paper. The rotor is biased with a homopolar permanentmagnetic flux, on which 2pole flux can be superimposed to generate suspension forces. Pdf reluctance force magnetic suspension characteristics. In conventional control method of suspension force for a bearingless brushless dc motor. Bearingless motors have been widely researched since they appeared. Additionally, the selected motor topology is optimized with finite element method fem simulations to improve the performance. The radial rotor position and the rotation are constantly measured by sensors. You should also make a dc measurement of stator winding linetoline resistance using a dmm. The technology uses the same stator windingscoils and can use a standard variable speed drive for operation. Introduction to induction motor the engineering projects. A combined sixphase winding is used for the excitation of the twopole motor field wave and the fourpole levitation field wave by applying two parallel threephase current systems.
A bearingless induction motor direct torque control and suspension force control based on sliding mode variable structure. Synchronous and asynchronous electromechanicalsystems dr. Recently, a variety of bearingless motorsincluding permanent magnet, induction. A new control method of suspension force for bearingless. The alternating current ac induction motor is one of the most rugged and most widely used machines in industry. In the paper there are presented the new construction of the bearingless motor, models radial magnetic forces and torque. Taking a 5phase induction motor as example, the inductance matrices, considering air gap eccentricity, are calculated with the modified winding function method. A cryogenic highpowerdensity bearingless motor for future electric propulsion nasatm2008215211 june 2008 paper no. Levitronix is the first company to introduce the bearingless motor technology, a breakthrough in magnetic levitation, to the market. The 3phase set of currents, each of equal magnitude and with a phase. Performance optimization design and analysis of bearingless. Although extensive research has been carried out on permanent magnet and reluctance types of bearingless motors, studies on the induction motor type are less successful. This controller can maintain rotor flux orientation of bearingless induction motor bim driven by indirect. A new control method of suspension force for bearingless brushless dc motor long shan, huangqiu zhu, weiyu zhang school of electrical and information engineering, jiangsu university, 2120 zhenjiang, china abstract.
In the process of motor rotation, the vibration caused by the rotor mass eccentricity seriously affects the dynamic characteristics and safety operation of system. Figure 1 shows a longitudinal view of an induction motor with its constituent parts. Bearingless induction motors combining functions of both torque generation and noncontact magnetic suspension together have attracted more and more attention in the past decades due to their definite advantages of compactness, simple structure, less maintenance. However, the bearingless induction motor bim has the advantages of low loss, low cost, simple structure, and withstanding high temperature, and it is easy to realize the openloop speed control by the voltage source inverter, which people are increasingly concerned with. Due to the similarity of structure between electric motors 4, 5 and magnetic bearings 6, a bearingless motor combine the functions of a motor. Analysis of a new 5phase bearingless induction motor. A linear induction motor lim is a specific type of alternating current ac, multiplephase machine that provides force and movement in a linear direction. Sep 27, 2016 induction motor is an ac electric motor, having a stator and a rotor just like other motors, but the working principle is a little different which would be discussed further.
First, on the basis of introducing the structure of 5degreeoffreedom bearingless induction motor, the mathematical model is derived. Speedsensorless vector control of a bearingless induction. A bearingless induction bi motor with an outer rotor for flywheel. Nonlinear decoupling control of the bearingless induction. No load characteristics of a bearingless induction motor, ieee industry applications society annual meeting part 1 of 2, 1991, pp. For a motor with low pressure relief valve, install poppet. The motor is mounted in a test rig that allows one to control the torque applied to the motor shaft and to measure both rpm and torque.
The result is a flat stator, or upper section, of iron laminations. The bearingless motor combined technical characteristics of motor and magnetic bearings. The stabilizing controller has the only task to keep the rotor stably suspended within the mechanical bounds and it does not present good periodic disturbance rejection. An induction motor or asynchronous motor is an ac electric motor in which the electric current in the rotor needed to produce torque is obtained by electromagnetic induction from the magnetic field of the stator winding. Bearingless induction motors combining functions of both torque generation and noncontact magnetic suspension together have attracted more and more attention in the past decades due to their. Topology choice and optimization of a bearingless flux. The rotor will constantly be turning to align its magnetic field with that of the stator field. Decoupling control of bearingless induction motor based on ls. A linear induction motor provides linear force and motion rather than rotational torque.
Eaton charlynn vis 45 series bearingless motors parts and repair manual cmolotm006e march 2008 3 vis bearingless motors 45 series parts list ref. Research on levitationrotation starting control system of bearingless induction motor 257. Liu adopt the nni control and internal model control method, and some simulation and experimental researches are carried out. Bearingless motors are a new type of motors, which combine the. The concept of bearingless motors, which combine both motoring and rotor bearing capabilities, is appealing especially in high speed and high power machine applications. Characteristics of linear induction motor considering. However, the traditional internal model control used in 21 has only one degreeoffreedom dof. A key feature that distinguishes bearingless motor technology is that it combines both the motor and magnetic bearing in the same unit.
That is the operation principle of the bearingless motor. Bearingless induction motors combining functions of both torque generation and noncontact magnetic suspension together have attracted more and more. An induction motor can therefore be made without electrical connections to the rotor. Choi national aeronautics and space administration glenn research center cleveland, ohio 445 mark siebert university of toledo toledo, ohio 43606 a 128 switchedreluctance motor ref. This allows further integration of the drive and, together with the bearingless disk topology, results in a highly compact drive unit. The prototype of high speed motorized spindle system with bearingless induction motor is studied and analyzed by using finite element analysis software ansoftmaxwell and riccati transfer matrix method, and compared with. For the induction motor, the steady state motoring region is restricted from 80% of the rated speed to 100% of the rated speed due to the fixed supply frequency and the number of poles. Induction motor driving a centrifugal compressor advantages. Finite element analysis and dynamics charateristic study.
Introduction i n recent years, there is an increasing interest in bearingless motors around the world. Remove two plugs from end cap end ported motors only. Electric motor electric motor linear induction motors. In the case of most conventional structures, each terminal. Design of a bearingless outer rotor induction motor mdpi. 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. A bearingless induction motor is a multivariable, nonlinear and strong coupling object. According to magnetic suspension motorized spindle system, high speed motorized spindle system based on bearingless induction motor is presented in this paper.
Magnetic bearings and bearingless drives akira chiba tadashi fukao osamu ichikawa masahide oshima masatugu takemoto david dorrell the application of bearingless drives is emerging as an important technique in the areas of highspeed machinery and motioncontrol, and this book aims to provide a thorough grounding in the principles behind this. A bearingless switchedreluctance motor for high specific. Design process of the proposed singledrive bearingless motor is shown. The theoretical assumptions are tested experimentally using a fourpole, two. The bearingless slice motor levitates and rotates a ringshaped rotor made of a semihard magnetic material. Bearingless motor, meaning that it has no mechanical bearing. Novel singledrive bearingless motor with wide magnetic gap. Performance optimization design and analysis of bearingless induction motor with different magnetic slot wedges. Single phase induction motor 1introduction the singlephase induction machine is the most frequently used motor for refrigerators, washing machines, clocks, drills, compressors, pumps, and so forth. The theoretical assumptions are tested experimentally using a fourpole, twophase machine without one mechanical bearing. Problems to reduce the coil end length of a winding of a rotating machine of a bearingless motor that generates torque and radial electromagnetic force in one electromagnetic machine, and has a high slot occupancy ratio, magnetomotive force distribution, and motor a bearingless motor having improved insulation between a winding and a support winding. The term bearingless originates from the same idea as the term sensorless.
Eaton charlynn vis bearingless motors cmolotm003e march 2008 5 vis bearingless motors 30 series reassembly 7. A bearingless induction bi motor with an outer rotor for flywheel energy storage systems is proposed due to the perceived advantages of simple rotor structure, noncontact support and high speed operation. Nonlinear differential geometry method and its application. So rotor mass eccentricity vibration compensation control on rotating machine has great significance, especially for the high speed bearing less induction motor bim. Relationship between reference and current vectors. It can simultaneously implemented electromagnet torque control and suspension control all in the motor. Full descriptions of the circuits and the tests are found in reference 1.
The prototype has been operated to a highspeed of 115. When the rotordeviates fromthe center ofthe motor stator, it will cause the motor flux distribution. Digital control system design and analyses of a 3phase. Characteristics of linear induction motor considering material of reaction plate change meng li school of electrical engineering, beijing jiaotong university, beijing, china email. The reactive powerbased model reference adaptive controller mrac is presented in this paper in detail to estimate rotor resistance online. There are two types of induction motors, one is named as single phase induction motor, while the second one is named as 3 phase induction motor. A novel singledrive bearingless motor with wide magnetic gap and high passive stiffness is proposed. In general, the induction motor is cheaper and easier to maintain compared to other alternatives. Keywords linear motor, active magnetic bearing, magnetic levitation, bearingless motor introductions bearingless motor or selfbearing motor, which has been widely developed for artificial heart since 1990s, is a combination of electric motor.
The rotor will constantly be turning to align its magnetic field with the stator field. Induction motor theory jerry bednarczyk, pe course content introduction the ac induction motor is well suited to applications requiring constant speed operation. In this paper, a simple, reliable and accurate analysis method is put forward using the concept of flux equivalent with virtual winding currents. Shaft voltages arise from various sources in electrical machines, such as winding faults, unbalanced supplies, electrostatic effects, magnetised shaft or other machine. A bearingless induction motor direct torque control and. The bearingless induction motor, which combines the induction motor and magnetic bearing is a strongly coupled complicated nonlinear system. Install one shuttle valve threaded internal hex plug with oring. These two windings are called motor windings and suspension windings, respectively. Electromechanical interaction in rotordynamics of cage. The purpose of this paper is to choose a new topology for bearingless fluxswitching slice motors, regarding the number of stator and rotor poles, with a combined winding set. Linear controller for maglev motor with axial flux. So the new motor eliminates the disadvantages of the conventional motor.
A bearingless induction motor system that uses standard windings is proposed. April 11, 20 6 of 10 the impedances of the circuits shown in figure 5 are found from noload and blockedrotor tests. Record all nameplate information for the induction motor. In order to improve the performance of the bearingless induction motor bim under large disturbances such as parameter variations and load disturbances, an adaptive variablerated sliding mode controller asmc is designed to obtain better performance of the speed regulation system. The derived model and the proposed controller design are verified by experiments with a hybrid hysteresis induction type bearingless motor. For high speed application magnetic bearings are necessary, which in the bearingless design are integrated into the active motor part. Nowadays, aiming at bearingless motor, the study on the radial displacement sensorless control technology based on lssvm has just started, and the existing research mainly focus on the bearingless synchronous motor.
Then the maxwellforceisnotzero,andthedirectionofitsactionand. Spwm, bearingless switched reluctance motor, power supply, dspic30f2010, ir2110. Research article inverse system analysis and modeling of. Be sure that the oil mist lubrication is connected and operating before starting the motor. A bearingless switchedreluctance motor for high specific power applications benjamin b. Development of bearingless motor with rectifier circuit. Sliding mode variable structure control strategy of. The construction of the motor is compound the active magnetic bearing and the more electric technology. A cryogenic highpowerdensity bearingless motor for future. Eccentricity detection of a sixphase induction motor with hfi. The model is validated through experiments with a hybrid hysteresis induction type bearingless motor, which is an ac motor with a solid rotor made of d2 steel. Highperformance control for a bearingless permanent.
Firstly, the configuration and operation principle of the proposed motor are described. Pdf bearingless induction motors combining functions of both torque generation and noncontact magnetic suspension together have. The induction motor is made up of the stator, or stationary windings, and the rotor. Firstly, the characteristics of unbalanced displacement signal. Aiming at bearingless induction motor, the references about lssvm displacement observation method is very scarce.
Performance optimization design and analysis of bearingless induction motor with. Introduction bsrm bearingless switched reluctance motor is a novel type of reluctance motors. Two sets of twophase windings are wound on the stator. The first prototype bm1 was designed for a rotational speed of. Recently, many kinds of bearingless motors have been studied, including bearingless induction motors 7,8, bearingless switched reluctance motors 9,10, bearingless permanent magnet synchronous motors. Speedsensorless vector control of a bearingless induction motor. Performance improvement of bearingless multisector pmsm. The stator is composed of laminations of highgrade sheet steel. Comparison between direct and indirect field oriented. Remove shuttle valve and relief valve if applicable from end cap. It is very important that this brace be reinstalled exactly as it was originally, before the motor is moved from storage or any time when the motor is being transported. Bearingless technology can be used in almost all kinds of alternating current motors 19.
May 15, 2009 a bearingless motor has two sets of intercoupling stator windings, namely torque windings and suspension force windings. Magnetic bearings and bearingless drives akira chiba. Thus, we obtain in coordinates associated with stator. Pdf development of bearingless induction motors and key. Abstractthe bearingless induction motor, which combines the induction motor and magnetic bearing is a strongly coupled complicated nonlinear system. Remove the 9 cap screws and disassemble the motor in the vertical position as shown in figure 1. In figure 3, the 4dof bearingless induction motor is split into two 2dof bearingless induction motors, which together provide the total torque and 2dof radial suspension of the rotor in the left and right shaft ends, respectively. A comprehensive description of a bearingless permanent magnet synchronous machine is presented including simulation, design, control and measurement focusing on a 1 kw60,000 min. Two highspeed bearingless permanent magnet pm synchronous motor prototypes with different mechanical and electrical ratings are presented from the design and performance point of view. In a sensorless drive, there are no discrete sensor units for measuring the rotor angle but the sensor functionality is integrated in the motor winding.
Control analysis of bearingless electric motor 50 mmasa mmbsa mmasb mmbsb mutual inductance between twopole suspension windings and fourpole motor windings. Synchronous and asynchronous electricmotors the electric motor is an electromechanical continuous energy conversion equipment that converts electrical energy into electrical energy mechanical energy. The decoupling control of the two sets is difficult and a key technology to stable operation for a bearingless motor. The mathematical model of radial suspension force on the singlewinding bearingless induction motor the magnetic potential vector graph about the singlewinding bearingless induction motor is shown in fig. The basic idea of an electric motor is to generate two magnetic fields. Since there are two sets of windings wound on the stator of bearingless motor, two sets of power circuit hardware and controller are required. Reluctance force magnetic suspension characteristics and. On a bearingless linear motor capable of selfmagnetic levitation wooyeon kim1, seungjong kim1, jongmin lee 1, sungchong chung2 and sang jo kim3 1energy mechanics research center, kist, 391 hawolgok, seongbukgu, seoul, 6791, korea. Numerous applications of lims can be found in industry today, one of the most interesting being high speed magnetic levitation railway systems. In this study, a novel method is proposed for eccentricity detection of a sixphase motor based on highfrequency injection hfi. The torquespeed characteristic of an induction motor can be significantly changed by designing. Bearingless induction motors combining functions of both torque generation and noncontact magnetic suspension together have attracted more. A hybrid control study of bearingless induction motor.
They can simultaneously produce the radial suspension force. Reactivepowerbased mrac for rotor resistance and speed. Install one shuttle valve poppet, spring and dash pot onto piston. This paper investigates the application of using magnetic wedges in a semiclosed slot bearingless induction bi motor. The derived mathematical model provides an effective basis for loopshaping control design for the reluctance forcebased magnetic suspension systems in bearingless motors. The shape and operation of a linear induction motor can be visualized as depicted in the figure by making a radial cut in a rotating induction machine and flattening it out.
Bearingless motor mechanism has functions of both a magnetic bearing and a. Pdf in order to effectively suppress rotor periodic synchronous vibration caused by the rotor mass eccentricity and sensor detection error of. To achieve its dynamic decoupling control with high performance and improve the system stability, a sliding mode variable structure smvs control strategy based on inverse system decoupling is proposed. Analysis and simulation of vector controlled bearingless. Described is a bearingless motor based upon a homopolar fluxbiased magnetic bearing for force generation and a hysteresis motor for torque generation.
Rotor mass eccentricity vibration compensation control in. Study on radial suspension force of single winding. A special feature of the winding system is that it creates both bearing forces and motor torque with the same set of windings. Design of a bearingless outer rotor induction motor. Sliding mode variable structure control of a bearingless. Pdf overview of bearingless induction motors researchgate. When an induction motor starts, it will draw very high inrush current due to the absence of the back emf at start. There are two major components of an ac induction motor. Shuttle plug threads may have light coat of oil or preservative. Induction motors horizontal and vertical weg electric machinery, wem, induction motors have been specifically designed and manufactured for the most severe industrial applications, such as heavy duty fans, pumps, refiners, compressors, crushers and grinding mill drives. In the same way, the radial suspension force inxaxis is obtained 10,11.1506 1230 988 974 368 174 887 1490 963 54 800 611 20 57 441 997 881 843 959 162 1091 248 1047 296 344 924 1213 534 202 1116 526 620 553 656 1328 1056 387 221 1479 687 441 407 1284 792 869 717 1470 10