The Control Strategy of Charging Converter of Super Capacitor Energy Storage Type Trolleybus

In recent years, the tram with super capacitor has gradually become a new trend of urban traffic. The purpose of this paper is to find a new strategy to improve the performance of super capacitor charging control in view of the interference caused by the poor contact between pantograph and rail in the process of super capacitor charging under the traditional PI double closed-loop control. This paper takes the super capacitor charging control system of energy storage type trolleybus as the research object. Based on the phenomenon of the system charging current increasing rapidly due to the poor contact between the pantograph and rail during the charging process of the tramcar, the problems such as the traditional PID control cannot effectively restrain the distortion of charging current caused by the poor contact between the pantograph and the rail are analyzed. Then a new charging control strategy is proposed, which adopts PI parameter setting of outer ring voltage loop and double closed loop control strategy of nonlinear differential tracker of internal current loop. Finally, by building the system control platform, the charging experiments of the two control algorithms are carried out under different actual conditions. The effectiveness of the proposed control method is verified by comparing the results of the two control strategies. Simulation results show that under the traditional control strategy, when the reference value of charging current is 300A, the charging voltage suddenly increases, from the voltage distortion of about 350V to about 385V, which has a large fluctuation, a large fluctuation range and inaccurate system control. Under the new control strategy, the current waveform of the control system with nonlinear system strategy is relatively stable, and the fluctuation and impact of disturbance are smaller.