The Research On The Super-Capacitor Stacks Equation System Of The Electric Bus

How to supply energy is one of the key technologies. Compare to the chemical cell, the super-capacitor has the advantage of large power density, low inner resistance, and fit to be charged or discharged in high current. Moreover, it has long cycle life, wide operating temperature range and good low-temperature characteristics. All these make it has unique advantage in pure electric city short distance buses, hybrid vehicles and electric vehicles powered by super-capacitor with battery or fuel cell.When the super-capacitors are connected in series, the cells lower in capacity are often over charged or over discharged, A long time in these states will lead damage to the cells. If the status is avoided simply by cutting down the charging and discharging current, the capacity of the super-capacitor stacks will not be effectively used, so it is of great significance for the super-capacitor stacks to be equalized and corresponding managed.The equation system of super-capacitor stacks is mainly researched in the paper. The evaluation means for the energy storage stacks equation system is brought forward, based on the means several equalizing methods are compared in system reliability, equalizing rate, equalizing precision, system efficiency, size of the system and so on. The"flying over to"capacitor equation system constitutes and control strategies are researched. The current limiting and controlling"flying over to"capacitor equalizing system is developed, and the relevant experimental results are showed. Especially the functions of the current limiting and the relay turning on and off without current achieved by joining the current limiting and controlling circuit are expatiated. In addition, considering further reducing system size, improving balance rate and lowering the price of the system, the equation system based on the electronic power devices is researched, the overall structure of the system and work sequencers are given out. Parts of the circuit are experimental studied. The debugging results of the driving and protecting circuit and equation unit circuit are showed.