A Control Method to Charge Series-Connected Ultraelectric Double-Layer Capacitors Suitable for Photovoltaic Generation Systems Combining MPPT Control Method

Abstract

A control method is described to charge series-connected ultraelectric double-layer capacitors (ultra-EDLCs) suitable for photovoltaic generation systems in combination with a maximum power point tracking (MPPT) control method. The EDLC charge control method allows the maximum power acquired by the MPPT control to be quickly charged into series-connected ultra-EDLCs no matter how the weather conditions may change. In the MPPT control, the output current of the solar arrays is controlled so that the output power converges on the maximum power in the prediction line previously determined based on the linearity between the maximum output power and the optimization current. The proportionality coefficient of the prediction line is automatically corrected using the hill-climbing method when the panel temperature of the solar arrays is changed. The EDLC charge control is performed with the three charge modes, i.e., the constant current charge mode, constant power charge mode, and the constant voltage charge mode while supervising the maximum voltage and allowable temperature of each series-connected EDLC. Effectiveness of the methods is verified by simulations and experiments