Research On Sliding Electrical Contact Failure And Contact Load Control Method Of Pantograph-catenary

During the operation of the high-speed electrified railway system,the contact state of friction pair which is composed of the pantograph slider and the catenary wire directly affects the operational stability,friction wear performance and the flow quality of the electric locomotive.With the increasing speed of the train,the dynamic contact pressure between the pantograph and catenary increases,and at high speed,the dynamic contact performance between the pantograph and the catenary wire becomes more and more unstable.Aiming at the practical problem,this thesis studies the sliding electrical contact failure and contact load control method under fluctuating load.In this thesis,through the immersion metal carbon slider and copper wire grinding experiment by the self-developed sliding electrical contact testing machine,the contact resistance characteristics with contact current,sliding speed,pressure fluctuation amplitude and pressure fluctuation frequency were obtained: as the sliding speed increases,the contact resistance increases rapidly;the contact resistance increases slightly with the increase of the fluctuating frequency;the contact resistance increases with the increase of the fluctuation amplitude,but the growth rate is slow;the contact resistance decreases rapidly with increasing contact current.The prediction model of contact resistance with contact current,sliding speed,pressure fluctuation amplitude and pressure fluctuation frequency was established by using the extreme learning machine(ELM).Based on the comprehensive consideration of contact resistance and current stability coefficient,the failure criterion of pantograph-catenary system sliding electrical contact was proposed.The contact failure mechanism of the pantograph-catenary system was analyzed.The increase of the fluctuation of the contact pressure and the sliding speed makes the frictional vibration between the pantograph and catenary intensify,and the contact resistance increases beyond the critical value and causes the failure of contact.Based on this,the failure probability model was established according to the probability distribution of contact resistance.Finally,the failure probability of sliding electrical contact of the pantograph-catenary system under certain working conditions can be obtained.Taking the binary coupling model of the pantograph-catenary system as the research object,for the fluctuation of contact load in the operation of the pantograph-catenary system,the sliding mode control method based on input and output feedback linearization was proposed and constructed a Lyapunov function to verify the stability of the system.The control system was simulated by Matlab/Simulink.The simulation results showed that the sliding mode controller proposed in this thesis has good tracking performance,which made the error between actualoutput load of the pantograph-catenary system and the target load minimize.As a result,the fluctuation of the contact load was suppressed by using the sliding mode controller and the flow stability were improved.Finally,the reliable contact of the pantograph system was guaranteed.