Design Of Simulation System For EMU Tunnel Pressure Wave And Research On Control Algorithms

With the rapid development of China's high-speed railway,its advantages of reliability,rapidity,economy and comfort bring great convenience for people to travel.However,when high-speed train is running at a high speed,especially through tunnels,there will be severe air pressure fluctuation outside the train.The air pressure fluctuation will enter the train through the body gap and air conditioning ventilation system,which will bring the problem of passenger pressure comfort inside the train.Therefore,with the increase of high-speed railway tunnels and the continuous improvement of high-speed train speed,the comfort of air pressure in the train has become a hot research topic.In order to conveniently study the air pressure comfort of high-speed trains passing through tunnels,this paper designs a ground air pressure wave simulation loading system for EMU,which can load the air pressure waves inside or outside of trains for a single carriage in the laboratory,thus simulating the real running conditions of trains.The pressure wave simulation system designed in this paper can be used to study the relationship between internal and external air pressure transmission of EMU,and the resistance of external air pressure by air duct structure,damping and control strategy of air conditioning ventilation system.At the same time,the system can be used to study the issue between air pressure and ear comfort.The system consists of three pressure tanks: positive pressure tank,negative pressure tank and loading tank.The air pressure wave outside trains is formed in the loading tank,and is connected with the fresh air outlet and waste exhaust outlet of the air conditioning ventilation system to simulate the air pressure wave of the tunnel outside the train when it is running.The positive and negative pressure tank is directly connected with the train body,which can load the air pressure inside the test train body to simulate the air pressure wave inside the train when it is running.Firstly,according to the requirement of pressure wave waveform,amplitude and rate of change,the overall scheme of pressure wave simulation system for EMU tunnel is designed,and the working state of the system is analyzed.Then,according to the requirement of pressure wave rate of change,the flow demand of the system is analyzed and calculated by using the law of conservation of mass and the ideal equation of state.And the sizes and thicknesses of positive/negative pressure tanks,loading tanks and corresponding pipes are calculated according to the relevant design standards of pressure vessels.Then the stress and strain of the three pressure tanks are analyzed by ANSYS software to ensure that the pressure tank meets the safety requirements and the deformation in the working process has no great influence on the loading of the waveform.Finally,the main components of the system are selected.When selecting the fan,considering the influence of the valve opening and flow coefficient on the pressure transfer in the system.Therefore,based on the relationship between valve opening and flow coefficient,the model of fan air volume and system pressure change is established.And the theoretical flow demand of system calculation is simulated and verified,and finally the type of fan is determined.In the aspect of system control simulation,the physical model of tunnel pressure wave simulation system is established in AMESim,and the iterative learning control algorithm is implemented in Simulink to realize the joint simulation of the two.Aiming at the simulated loading of the pressure wave in the tunnel outside the vehicle,the control effects of three kinds of iterative learning laws are compared.The simulation results show that the open-closed loop high-order iterative learning law with forgetting factor has faster convergence speed,higher control accuracy and smoother control effect.In terms of learning speed,the learning speed of open-loop first-order,closed-loop first-order,open-closed-loop second-order and open-closed-loop third-order ILC with forgetting factor is compared for reference pressure.It is found that the learning speed of closed-loop is better than that of open-loop,and the learning speed increases gradually with the increase of the order of the algorithm.Finally,it is verified that the forgetting factor open-closed loop third-order iterative learning control also has a good tracking effect on the tunnel pressure wave of the train tail.