PID Active Control Strategy Of Pantograph For Electrification Railway

With the rapid development of high-speed railway,the current collection problem of train at high speed has become an important reason for restricting the reliable,safe and stable operation of train.The trainrelys on the sliding contact between the pantograph and the catenary to obtain electric energy.As the speed of train increases,the dynamic contact between the pantograph and the catenary becomes more and more unstable.When the contact force between the pantograph and catenary is too large,it will cause the mechanical wear of the catenary of the pantograph.When the contact pressure is too small,it will separate between pantograph and catenary,and the offline arc will ablate the carbon skate and the contact wire.Therefore,it is necessary to adopt the active control strategy to reduce the contact pressure fluctuation between the pantograph and the catenary,and to improve the quality of the current collection.The main contents are as follows.Firstly,completed the pantograph active control scheme selection.The active control system uses DSP as controller and stepper motor as power mechanism and it replaces the current commonly used microcontroller as the controller,the cylinder and hydraulic pressure drive control program.The linear stepper motor controlled by the DSP drives the pantograph to rise or fall,so that the pantograph contact pressure is kept within a reasonable range.Then,hardware design of the pantograph active control system are performed around the laboratory pantograph simulation device.Hardware design including controller selection,pressure sensor selection,amplification filter circuit design,and stepper motor driver design.Secondly,based on Simulink,the pantograph and catenary model,the two-phase hybrid stepper motor model,fuzzy controller,fuzzy PID controllerand the whole control system model are established respectively.Through the simulation method,the control effect of PID active control,fuzzy control and fuzzy PID control on the contact force fluctuation between catenary and the pantograph is studied.When the mean square deviation of contact pressure fluctuation and the response speed as the evaluation indexes,the three control algorithms have little difference in the mean square,and the PID active control algorithm is the fastest.Therefore,pantograph PID active control scheme was chosen.Then,completed the control system software design around PID control algorithm.Software includes AD acquisition program design,software filtering program design,PID control algorithm programming,PWM output programming,serial communication program design.Finally,the active control experiment was completed on the laboratory simulator.Completed the PID parameter selection experiment,the target contact pressure test experimentand the pantograph PID active control dynamic experiment.For the first time,the PID control of the pantograph was implemented in the laboratory.It was proved that the PID control strategy of the pantograph can effectively reduce the contact pressure fluctuation between the pantograph and the catenary and improve the quality of current collection thought experiment.