Overview of Bearingless Induction Motors

Abstract

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. This paper overviews the key technologies of the bearingless induction motors, with emphasis on motor topologies, mathematical models, and control strategies. Particularly, in the control issues, the vector control, independent control, direct torque control, nonlinear decoupling control, sensorless control, and so forth are investigated. In addition, several possible development trends of the bearingless induction motors are also discussed.

A Parametric Solution to the Generalized Bias Linearization Problem

“…These motors use a primary sinusoidal winding to generate torque and a secondary sinusoidal winding to produce a different harmonic of flux density that controls the motor's bearing forces. The history of this sort of motor is reviewed in Reference [25]. A representative layout is shown in Figure 2.…”

Sliding mode variable structure control strategy of bearingless induction motor based on inverse system decoupling

“…where d 3 is the external disturbance, |d 3 | ≤ h 3 , h ≥ 0; y 3 and v 3 are the same as those in (6) and (8). Assumption: r 3 is the given instruction.…”

“…The AC motor supported by mechanical bearings widely used in industrial fields [1], but it cannot meet the need for high speed and long operation time. Thus, a motor supported by magnetic bearing was widely developed [2][3][4][5], but it still has some disadvantages, such as more power consumption for magnetic suspension, overspeed difficulty, etc. [6][7][8][9][10].…”

Inverse System Analysis and Modeling of Bearingless Induction Motor and Its Combined Control Strategy

“…Although conventional motor with mechanical bearing has been widely used in the field of industrial production [1][2][3][4], it cannot meet the need of long time high-speed operation. Then motor with magnetic bearings is developed and widely used in high-speed drive kingdoms [5][6][7], but it still has a series of disadvantages [8][9][10][11], such as higher magnetic suspensions cost and difficulty to overspeed. Based on the comparability of stator structure between magnetic bearing and conventional AC motor, the bearingless motor is proposed [12][13][14][15].…”

“…Compared with the motor with magnetic bearings, bearingless motor owns a series of advantages, such as shorter rotor shaft and higher critical speed, and then it is more suitable for the long time and high-speed running. Now, urgent needs for bearingless control technology of motor have been proposed in the kingdoms of sealed transmission, aerospace, and advanced manufacturing [10,13,16]. Bearingless control technology can be used with all kinds of AC motors [8].…”