Direct controller of radial displacement of bearing-less asynchronous motor rotor

Abstract

The invention discloses a direct controller of a radial displacement of a bearing-less asynchronous motor rotor. The direct controller is composed of a rotary speed controller, a radial displacement closed-loop controller and a torque winding air gap flux linkage estimation module; the rotary speed controller outputs a three-phase current to an electric motor torque winding; the radial displacement closed-loop controller is composed of a rotor eccentric displacement and eccentric angle computing module, a neuron PID controller, a levitation force winding current computing module, a three-phase power pulse-width modulation (PWM) inverter, a radial displacement sensor and a photoelectric encoder; according to the levitation force winding current computing module, five variables such as the radial levitation force amplitude, the rotor eccentric angle, the torque winding air gap flux linkage amplitude, the phase and the rotor position angle serve as inputs, three-phase levitation force winding current command values i'<2A>, i'<2B> and i'<2C> serve as outputs, and three-phase levitation force winding currents i<2A>, i<2B> and i<2C> required for stable rotor levitation are obtained through the three-phase power PWM inverter; the direct controller is simple and practical in structure, and independent control of the electromagnetic torque and the radial levitation force of a bearing-less asynchronous motor is achieved.

Description

Technical field [0001] The invention is a controller scheme that directly controls the radial displacement of the rotor of a bearingless asynchronous motor to achieve stable suspension and high-speed rotation, and is suitable for many applications such as high power, ultra-high speed, high electromagnetic efficiency and high space utilization. The special electric drive field of bearing asynchronous motor belongs to the technical field of electric drive control. Background technique [0002] The use of electromagnetic bearings to support the rotor of a bearingless motor and accurately control the radial displacement of the rotor to achieve stable suspension of the motor rotor has always been the focus and difficulty of the research on bearingless motors. There are two main motor rotor suspension force control methods that have been proposed: the vector control method and the direct suspension force control method, which can basically realize the control of the motor rotor radial ...

AI Technical Summary

Problems solved by technology

There are two main methods of controlling the levitation force of the motor rotor that have been proposed: the vector control method and the direct levitation force control method, which can basically realize the control of the radial levitation force of the motor rotor, but both control methods have obvious deficiencies: The vector control method requires cumbersome coordinate transformation, which increases the complexity of the control system software and takes up too many system clock cycles; the direct levitation force control method requires online identification of the radial levitation force of the motor rotor, which not only increases the system hardware Design cost, and the identification accuracy of radial suspension force also determines the overall control performance of the system, and can only be applied to specific types of motors, and it is difficult to be widely used

However, there is a serious coupling between the electromagnetic torque and the radial suspension force of the bearingless asynchronous motor, which makes the design of the control system of the bearingless asynchronous motor more complicated.

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