A Study of Super-Capacitors Charge Efficiency

In this article, the arithmetic model of super-capacitors in photovoltaic system and more charge modes, especially constant power charge mode, was studied. A numerical way of calculating the charge efficiency was introduced. The maximum charge efficiency of super-capacitors when its output voltage raises from zero to the rated voltage under constant power charge mode was presented. The multi-stage charge efficiency curves was retrieved, which indicates that the constant power charging mode is more suitable. The constant power control charge strategy using two-stage Buck-Boost converter to charge super-capacitors was proposed. The simulation results show that this strategy effectively ensure the performance of the system.