Study On Hybrid EMS Technology

The maglev technology, a new-tech emerged in 20th century, has been progressed a lot in recent years. It is widely applied in transportation, metallurgy, mechanism, electrical equipments and material researches. The maglev train, a new railway vehicle without friction, is one successful and important application of maglev-tech.The structures of the traditional EMS and EDS are relatively simple and reliable. But there are obvious shortcomings in these maglev systems. In the traditional EMS, there is resistance in normal-conduct windings, therefore, energy loss cannot be ignored, the enlargement of gap is limited and a higher rail precision is required. Usually, the low temperature superconductive magnetizer is used in EDS. Although in EDS, the suspension gap is larger than EMS, the suspension windings arrange separately, and vertical suspension isn't controlled in closed-loop, so the performance of comfortableness isn't ideal;intensive magnetic field without closed magnetic circuit in carriages may be deleterious to human's health.Aiming at the problems mentioned above, this dissertation describes two kinds of hybrid electromagnetic suspension(EMS) systems, and the pure EMS system made of HTS coils has also been discussed. Three EMS systems have been researched in this dissertation, the single-magnet suspension experiment platform was devised to validate the feasibility of the three types of EMS systems using in electromagnetic rail transportation respectively. The study on the hybrid EMS system was meaningful in electromagnetic rail transportation theoretically and practically.Three kinds of EMS suspension systems have been elaborated based on finite element analysis in this dissertation. According to the characteristics of permanent magnet and HTS material, the single-magnet suspension experiment platform was devised, which can meet the requirements of the three kinds of suspension systems respectively;Operating principle and mathematical model of the EMS suspension systems are analyzed respectively, and the controller is designed;Theoretically, we analyzed the feasibility and make simulation;The four-quadrant chopper and the controller based on DSP were devised, and the two kinds of hybrid suspension systems and the pure HTS suspension system can be stably suspended;finally, compared to the traditional normal electromagnetic suspension system, the respective about new types of suspension systems was predicted.The structures of hybrid EMS suspension systems and the pure HTS EMS suspension system are more complex than that of the pure electromagnetic EMS suspension system;and the complex structures also make the operating condition and control strategy more difficult. While the hybrid suspension systems can greatly consume less power and realize greater suspension gap. As a result, demand for the precision of guideway is deduced, meanwhile the capacity and weight of the accumulator can be decreased, and the self-weight of the vehicle is also lighter. So the cost of the guideway project is less. In addition, with the quick development of the HTS material and the refrigeration technology, the suspension system with hybrid electromagnets made of HTS coils and normal conductor coils and the pure HTS EMS suspension system will be widely applied in the maglev train.