Dynamic Characteristics Of Controlled-PM Maglev Systems With Different Thickness Permanent Magnets

The structure of the magnets of traditional electrical magnetic suspension (EMS) system isrelatively simple and reliable, and it is relatively easy to manufacture such kind of magnets. Butthere are some obvious shortcomings of this kind of magnets mostly because the current of themagnets is great so as to the magnets consume too much energy. But, the controlled-PM maglevsystem can generate a majority of levitation force by using permanent magnets. Thus, the powerconsumption of system and the capacity of the batteries are decreased greatly. At the same time,the levitation air-gap can increase properly and the cost of the track can decrease evidently. Withthe progress of manufacturing technique of the high performance, low price rare earth permanentmaterial such as neodymium-iron-boron (NdFeB), the right time of using hybrid magnets withcontrolled permanent magnets (PM) comes. This paper studies mainly on the dynamiccharacteristics of controlled-PM maglev system with different thickness permanent magnets, anddevelop a set of experiment model which can realize the suspension of controlled-PM maglevsystem. So the characteristics of controlled-PM maglev system with different thickness permanentmagnets are validated by doing experiment.In this paper, the time constant of controlled-PM maglev system is compared with the timeconstant of electrical magnetic system under some conditions. Because of the existence of leakagemagnetic field, the time constant of controlled-PM maglev system is less than the time constant ofelectrical magnetic system. Based on this, the dynamic characteristic of controlled-PM maglevsystem is better than the dynamic characteristic of electrical magnetic system.The characteristic curve of controlled-PM magnetic pole is very important. The choice ofmaglev chopper parameters, the design of maglev control system and the working range of thesensor are confirmed based on this characteristic curve. The characteristic curves of controlled-PMmaglev system with different thickness permanent magnets are mainly studied in this paper.The compare of the dynamic characteristics of controlled-PM maglev system with differentthickness permanent magnets is given by using the state feedback controller. The controlled-PMmaglev system with different thickness permanent magnets can realize suspension steadily byusing the same controller with the same controller parameters. The thicker permanent magnet is,the better dynamic characteristic of the system becomes. But there exists a best thickness ofpermanent magnet for one controlled-PM maglev system under certain conditions. This best valueis the thickness which can provide the force that is close to the gravitation of controlled-PMmaglev system.The controlled-PM maglev technology can decrease the power consume of magnetic pole andoptimize the structure of electrical magnetic system and decrease the cost of the whole system. Soit is a foreground science technology.