Power-Management Strategies using Super Capacitor for Grid-Connected PV-FC Hybrid System

Abstract

In this study, we provide state-of-the-art power-management algorithms for improving the performance of grid-connected hybrid systems that include a photovoltaic fuel cell (PV-FC) array, a proton exchange membrane fuel cell (PEMFC), and a super capacitor. Unit-Power Control (UPC) and Feeder-Flow Control (FFC) are the two separate modes of operation of the hybrid system. Under UPC mode, the main grid compensates for fluctuations in load demand by regulating the output of the hybrid source to a reference power. To make the most of fluctuating temperatures and irradiance, the PV array uses a Maximum electricity Point Tracking (MPPT) method to optimally capture electricity. The incorporation of alternate sources, such PEMFC, is necessary to boost system controllability due to the inherent intermittency of PV energy. PV energy is reliant on weather conditions and is unavailable during nighttime. By keeping the feeder flow constant in FFC mode, the hybrid source can handle increased load demand. Accurately determining the feeder reference power is necessary for this. System stability is guaranteed by the suggested technique, which permits a flexible transition between operating modes according to load requirement. Hysteresis is used to reduce the variance in the reference power of the hybrid source and avoid unwanted mode transitions. Improved system performance, stability, and reduced operating mode transition frequency are all results of this strategy's continual optimization of PV array output and PEMFC efficiency. Adding a Super Capacitor to a grid-connected PV-FC hybrid system improves energy management, which in turn increases the system's efficiency and reliability.