Optimal Design And Realization Of Relative Position Detection Sensor For High Speed Maglev Train

The speed and location detection system of a high speed maglev train providesnecessary position, speed and running direction information of the train to achieve thereliability and safety in operation, and it also provides the secondary phase signal of theelectromagnets for the traction system when the train is running at a low speed, so it isone of the core technologies for a high speed maglev train. In order to realize theindependent research and invention of the high speed maglev traffic technology in ourcountry, this thesis mainly focuses on the optimal design of the relative positiondetection sensor which is a key device of the speed and location detection system. Therelative position detection sensor obtains the relative position, magnetic phase, runningdirection and speed information of the train by detecting the tooth-slot structure of thelong stator. Aiming at solving some problems of the existing sensor, this thesis mainlyresearches on five aspects, shown as follows:Firstly, the electromagnetic model of the relative position detection sensor is builtand its electromagnetic characters are analyzed. The multipole theory based onsecond-order vector potential is introduced to build the electromagnetic model of thesensor, and the solution of the electromagnetic field is expressed in terms of seriesexpansions. Based on the modeling results the influence of the winding eddy-currentand the suspension height on the electromagnetic characters of the sensor are studied.Secondly, the detecting coils of the sensor are designed and improved. Theresonance mode of the coils is determined. Considering the characters of some otherexisting coil structures, a new coil structure is raised, and the influence of the geometricparameters on the coil characters is studied, and then the optimal geometric parametersare determined.Thirdly, the positioning method of the sensor is improved and designed. Thepositioning method is designed, and the influence of suspension gap fluctuation on thesensor signals is studied in detail. To eliminate the influence, a dynamic DCcompensation method for the difference signal of the sensor is proposed and itseffectiveness is verified through simulation.Fourthly, the problem caused by the joint gaps on the long stator is studied. Aimingat solving the signal distortion of the sensor when it’s passing joint gaps on the longstator, a new tracking-differentiator is proposed. Then, a signal filtering algorithm and asensor switching algorithm are designed to solve the signal distortion caused by thejoint gaps effectively based on the tracking-differentiator in the upper layer of thesystem (the magnetic phase signal processing unit).Fifthly, the engineering implementation and experiments of the sensor areperformed. The hardware circuits and software algorithms of the sensor and the magnetic phase signal processing unit are designed, and the ground experiments andon-board experiments are performed.According to the results of theoretical analysis and experiments on the Shanghaihigh speed maglev test line, the optimal design in this thesis can improve theperformance of the relative position detection sensor effectively.