Low Power Consumption Nonlinear Control with H∞ Compensator for a Zero-Bias Flywheel AMB System

Abstract

A nonlinear control approach based on a control current switching rule is studied experimentally for an energy storage flywheel active magnetic bearing (AMB) system. In the proposed control, only one electromagnet in each axis of the AMB has a current flow at any given time, depending on the rotor displacement. This results in a power consumption that is lower than a linear control employing a bias current. The equation of motion for the rigid rotor-AMB system is transformed to have a decentralized structure for the control design. To compute nonlinear control currents, an H,,. compensator is designed for each axis of the AMB. The proposed approach is experimentally verified using a high-speed digital signal processor.

Regulation on radial position deviation for vertical AMB systems

“…Nonami et al [5] ever tried to employ H N theory for the controller design for AMB-based milling machines and implementation via DSPchip and electronic technology. Sivrioglu et al [6] improved the efficiency of energy storage flywheel supported by AMBs, by applying H N controller and multiple-equilibriums linearization. Chen et al [7] introduced integral sliding mode controller to stabilize three-axis AMB systems with uncertainties Castano et al [8] integrated H N , Quantitative Feedback Theory and Nichols chart to enhance trajectory tracking capability of the closed-loop systems [8].…”

An Appraisal of Power-Minimizing Control Algorithms for Active Magnetic Bearings

“…In order to reduce the power consumption of AMBs due to bias currents, several power-minimizing control algorithms have been proposed. These power-minimizing algorithms either eliminate bias currents (zero bias) [2][3][4] or use low-bias currents [5][6][7][8]. All zero-bias methods involve a certain kind of switching and are affected by the singularity at the zero-bias state.…”

“…The performance of the power-minimizing controllers is assessed through this model using frequency-domain techniques. Of many power-minimizing controllers in the literature, we select two controllers for comparison: the variable bias controller by Sahinkaya and Hartavi [8] and the switching controller by Sivrioglu et al [4], partly because these controllers were experimentally validated. A more important reason for this selection is that although these two controllers are either nonlinear or adaptive, it is still possible to use the SV-based frequency-domain technique for the assessment.…”

“…The optimal bias current and the proportional gain are computed by (21) and (22), respectively.4.3. Switching Controller.Using the feedback linearization, the switching controller by Sivrioglu et al[4] linearizes the plant through a switching rule. Referring to the 1D actuator inFigure 1, a dynamic model for the rotor can be written as = mag .…”

Adaptive control of nonlinear zero-bias current magnetic bearing system

“…As a control design approach, Queiroz and Dawson [6] have proposed to solve control problems using the nonlinear integrator backstepping for active magnetic bearing applications. To reduce power losses, low-bias and zero-bias control of active magnetic bearings are studied in [7][8][9][10][11].…”