Research On The Dynamic Optimization Of The High Speed Electromagnetic Suspension

With the improvement of working efficiency in modern society,people’s demand for high-speed transportation is increasing day by day.However,the traditional wheel-rail vehicle is unpractical to break through to a higher speed due to the limit of various factors.In this situation,maglev trains stand out for its advantages such as high speed,low energy consumption,low noise,low costs and so on.In this thesis,taking the Germany TR08 and Shanghai high speed EMS train as references,the dynamic model coupled with machinery,electricity,magnetism and track is established after the in-depth study on the structure and principle of high-speed EMS.According to the structure and principle of the electromagnetic levitation system,a two-dimensional finite element model for the calculation of the suspension system of the magnetic levitation vehicle was established.Then,the finite element calculation results and the simplified formula calculation results were quantitatively compared,and the model of high-speed EMS vehicle-electric-magnetic coupling based on co-simulation was established.Based on the above coupling model,the structure and parameters of the vehicle suspension system were analyzed and optimized aiming at vehicle running stability and curve-passing performance.According to the electromagnetic suspension control system model,the stability bifurcation of the linear system,the nonlinear system and the mechanical-electric-magnetic coupling system is studied.The system’s suspension control parameters were optimized with the aim of the shortest stability time of the suspension electromagnet.The three-dimensional finite element model of the high-speed magnetic levitation track beam was established and imported into the vehicle system to form a coupling model with the mechanical-electrical-magnetic-track,and the dynamic response of the vehicle-track system was simulated and analyzed,such as the influence of the support stiffness of the track beam and the speed of the vehicle for the dynamic response of the vehicle and track system.In this thesis,the following main conclusions are obtained:1)It is feasible to use the simplified formula to calculate the electromagnetic force when the excitation current is small and the suspension gap is no less than a certain value and within a small range.2)It is concluded that there are advantages and disadvantages of the two suspension schemes with and without bolster according to the comparison result of the suspension system structure of the electromagnetic suspension vehicle.When passing the curve,the lateral displacement and vertical displacement of the air-spring and the car-body under the scheme without bolster are far bigger than those under the scheme with bolster.So,the structure of high-speed EMS train with bolster is still reserved considering the actual cost and the curve passing capacity of the vehicle.3)Aiming at the running comfort of the vehicle,the vertical stiffness of the air spring,the lateral stiffness of the auxiliary spring and the torsional stiffness of the bolster around the X-axis should be taken as the smaller values within the feasible scope of the project.However,if too small values are taken for them,the displacement of the air-spring and the car-body will get lager when aiming at the curve passing.The vertical stiffness of the bolster connection has little impact on the ride comfort but can ensure that the displacement of the air-spring and the car-body are smaller when passing the curve by taking larger value.4)According to the stability study of the EMS control system,it’s known that there are upper and lower bifurcation points for the parameterK_p for the EMS control system.The control system is stable in the lower and upper sections,and unstable outside the sections.After optimization analysis,the value range ofK_p which can make the vertical vibration of the EMS train stable rapidly is 15000～20000,and the value range ofK_d is 1300～2000.5)According to the simulation analysis of the EMS train coupled system,it is found that the support stiffness of the track beam has little influence on the dynamic index of the vehicle system.In order to reduce the vertical vibration of the track beam,a larger support stiffness should be selected within the engineering permissible range.The vehicle dynamics indexes increase with the increase of the vehicle speed,but each index does not exceed the excellent limit within the design speed of 660 km/h.At the same time,the dynamic response index of the track beam can meet the design requirements of standards.