Research On The Control Strategy Of Controlled PM On A Maglev Model Vehicle

The structure of the magnets of traditional electrical magnetic suspension (EMS) system is relatively simple and reliable, and it is relatively easy to manufacture such kind of magnets. But there are some obvious shortcomings of this kind of magnets. Its heavy-expensive battery, long distance power rail and linear generator mounted on the surface of the magnet are necessary to provide levitation power. These not only increase the cost of the maglev line, but also decrease the payload ratio and running performance of linear synchronous motor (LSM). Meanwhile, it requires very high precision of the track that causes the high cost for the long distance maglev line. So if the power that the suspension magnets consume can be lowered markedly, the length of the power rail can be shorted accordingly or even be canceled, and the rated air gap can also be increased, which are very significant for the decrease of the construction cost and the enhancement of the reliability of the maglev system. With the progress of manufacturing technique of the high performance, low price rare earth permanent material such as neodymium-iron-boron (NdFeB), the right time of using hybrid magnets with controlled permanent magnets (PM) comes. This paper describes a new maglev model vehicle using hybrid magnets for levitation with linear generator. Hybrid magnets act also as the drive magnet of linear synchronous motor (LSM) that provides the thrust force. Also different control strategies of the hybrid magnets are studied and a set of control system are developed for the maglev vehicle model. Experiments are also done to verify the validities of the control strategies.The control strategies of EMS maglev systems can be divided into two types. They are linear control and non-linear control respectively. State feedback control is a traditional control strategy for EMS maglev systems that is simple, and easy to be realized by analog devices. Because the parameters of an EMS system are nonlinear and time-varying, the traditional state feedback control strategy can not make the...