Research On Energy Storage System Based On Super-Capacitor

Recently, the super capacitor as a modern new energy storage equipment has stepped into a high degree of development and application stage with the continuous development of energy-saving technologies and new energy industry’s needs, which has a distinct advantage better than the traditional electrochemical energy storage device. The characteristics, such as the high speed of charge and discharge, the large power density, long life and so on, are particularly suitable for systems used in energy recovery. The super capacitor energy storage system is an important option for energy management.Firstly, this paper introduces the basic working principle and charge-discharge characteristics of the super capacitor, then describes the model of the super capacitor. Generally, Super capacitor has a low rated voltage and the less effective energy than battery, so we need several series or parallel super-capacitors. The deviation, the equivalent series impedance and the leakage current of the super capacitor all have an effect on imbalance of the terminal voltage during charge and discharge, and leading to the bad efficiency and service life of the system. Therefore, the super-capacitor group must be pressed, and by applied the power constraint method and the energy constraint method to optimize the design of the super capacitor group.Because the changing of the super capacitor bank charge and discharge terminal voltage, a bi-directional DC-DC converter between the energy storage unit and load is necessary. This paper mainly analyses bi-directional half-bridge DC-DC converter, and the bi-directional DC-DC converters has two operating modes namely Buck mode and Boost mode and has built mathematical models of Buck mode and Boost mode. This paper has analyzed the control strategy of the potential energy load of energy recovery system, studied a simulation of two control strategies of the current limiting and voltage regulator and the rapid discharge, also analyzed and validated the strategy from the changing of super capacitor terminal voltage, current and DC bus changes. Finally, the prototype of a super capacitor is designed which can be experimentalized charging and discharging.