Optimal control of a magnetic bearing without bias flux using finite voltage

摘要: Conventional active magnetic bearings (AMB) are operated using a bias current (or flux) to achieve greater linearity and dynamic capability. Bias, however, results in undesirable rotating losses consequent rotor heating. While control without flux is an attractive alternative, it considerably more complex due both force slew rate limitations actuator non-linearity. In this paper, optimal of bearing investigated. A single-degree-of-freedom system consisting mass two opposing electromagnets considered. The problem examined for cost function that penalizes poor regulation rotational energy lost. Though standard optimization procedure does not directly yield analytical solution, show the always bang–bang including possibly singular arc. First, minimum time solved simple switching law three dimensional state space. non-standard, physics-based approach then employed obtain solution general problem. final result variable structure feedback controller. This provides benchmark which can be used evaluation performance practical controller designed via other methods. will support flexible robustness optimally reject disturbance. may also applied many applications contain quadratic actuators. © 1998 John Wiley & Sons Ltd.