A New Active Control Strategy for Pantograph in High-Speed Electrified Railways Based on Multi-Objective Robust Control

In high-speed railways, the quality of current collection of high-speed train is directly determined by the contact force between the contact wire of the catenary and the registration strip of the pantograph. In order to ensure a stable contact force, this paper proposes a control strategy for active pantographs by minimizing the acceleration of pantograph collector. The model of pantograph-catenary interaction is established based on the finite element approach and the multibody dynamics. A Kalman filter is designed to obtain the states of the pantograph considering complex electromagnetic circumstances and severe physical environments. According to the equation of motion for the pantograph-catenary system, the implicit expression of pantograph-catenary contact forces is derived. The factors causing the fluctuation of the contact force are analyzed to determine the three control targets, which are minimize the acceleration of pantograph collector, limit the control force and displacement constraint. At last, a multi-objective robust control method based on state estimation is designed. The robustness and effectiveness of the control method are verified on a nonlinear pantograph-catenary system model under different work conditions. The results show that the error between the estimated value and the true value of the pantograph is between 0.06% and 3.46%. The standard deviation of contact force is reduced by 29.55%, 25.26%, and 20.86% under different operational speeds, respectively. The standard deviation of the contact force was still reduced considering the parameter perturbation of pantograph and the unevenness of contact lines. The result of proposed control strategy is better than previous work, even though the proposed controller requires a lower energy consumption. In addition, With the proper pre-treatment of the active control force, the movement number of the actuator is reduced and the control performance is still fine.