Poor stability of the permanent magnet electrodynamic levitation hinders its application in the maglev field. Therefore, building a control-oriented model to improve its stability is most challenging. However, intractable electromagnetic models leading to an implicit relationship between levitation force and gap, yields a barrier for model-based controller design. To solve the above-mentioned problem, this paper develops a control-oriented model by two stages. Specifically, the first stage is to show an explicit formula of the levitation force with regard to the levitation gap by neglecting end effect; meanwhile the “maximum–minimum rectification” method is put forward to evaluating an accurate levitation force. The second stage is to bring forth the control-oriented model on basis of the estimated levitation force. Although the paper focus mainly on the development of the control-oriented model, an example of PD controller is provided to verify its validation. Experiment results demonstrate the estimated levitation force is highly consistent with the real one. Simulation results show that the control-oriented model is sufficiently reliable. The research bridges the gap between the physical model and the model-based controller for the electrodynamic levitation with permanent magnet Halbach array.
Progress in the Levitation Force of Radial-type High-TC Superconducting Magnetic Bearings
