Research on Dynamic Decoupling Control Method of Three-phase Bearingless Induction Motor

Abstract

Three-phase bearingless induction motor is a multi-variable, nonlinear and strong coupling object, to achieve its high performance control, the dynamic mathematical models was analyzed firstly. According to the derived mathematical model, the reversibility of bearingless induction motor system was discussed, and the dynamic mathematical models of inverse system were derived. Then, based on the inverse system method, the dynamic decoupling control strategy of three-phase bearingless induction motor was researched, and the dynamic decoupling control system was build. Simulation results show that the dynamic decoupling control has been achieved between motor speed, rotor flux linkage and two radial displacement components, and the control system has higher dynamic and static performance; the presented decoupling control method is effective and feasible.

Development of Bearingless Induction Motors and Key Technologies

“…16, the airgap flux linkage of torque winding is obtained from the airgap flux observer, and the rotor flux is no longer affected by the torque current, which realizes the effective decoupling between torque and suspension force. A decoupling control system combining airgap fieldoriented control and rotor field-oriented control was proposed in [30]. The rotor field-oriented control was used in the torque control, and the airgap field-oriented control was adopted in the suspension force control.…”

Decoupling Control Strategy of BLIM Based on Neural Network Inverse System

“…But, the differential geometry method often solves relevant problem in the geometric domain, the mathematical operation is complex [12]. Inverse system method is achieved by nonlinear feedback and linearization, its physical concept is clear; but the accurate inverse system model of bearingless motor is complex also [10,13,14]. Neural network can approximate the complex nonlinear function with arbitrary precision, and has the self learning ability; it can be used to control the bearingless motor.…”

Compensation and Control of Bearingless Induction Motor’s Unbalanced Exciting Force Based on LMS Filter

“…Motor with magnetic bearings has been widely used in high-speed drive kingdoms [3][4][5], but it has a series of disadvantages, such as: higher magnetic suspensions cost, difficulty to over speed, [6][7][8]. Based on the comparability of stator structure between magnetic bearing and conventional AC motor, the bearingless motor is proposed [9][10][11][12]. Bearingless motor is a new type of electric machine applicable for high-speed operation.…”

“…When the qualification of "p 2 =p 1 ±1 ， ω 1 =ω 2 " is met, the resulting radial electromagnetic force is controllable either in amplitude or in direction. The controllable radial force is so-called magnetic suspension control force; witch can be used to control the suspension of rotor [9][10][11][12].…”

“…For simplicity, ignoring the influence of rotary effect and the random displacement of bearingless rotor; according to Newton"s law, the motion equation of the rotor"s geometric center along α and β directions can be expressed as following [9,12]. 2 2 2 cos( )…”