Power management and control strategies of PV-FC hybrid system with storage in grid connected mode

摘要

Analysis of power management and control strategies for hybrid system with storage in grid connected mode is presented in this paper. Photovoltaic array, fuel cell, battery, super capacitor are used as hybrid sources. Photovoltaic array alone with Maximum power point tracking technique makes it uncontrolled source. To satisfy demand and to take care of uncontrolled PV source, additional sources such as fuel cell, and storage elements such as battery and super capacitor are connected to hybrid system with grid connected mode. Two power flow controlling methods unit power flow control (UPC) and feeder flow control (FFC) is presented in this paper which ensures stable system operation with grid connected mode. In both the modes PV array works with its maximum power point tracking technique along with fuel cell maximum efficiency limit thus enabling the combination (PV-FC) to work in its high efficiency mode. Use of battery ensures the stable operating voltage at hybrid source terminals and improves the system capacity and stability. The performance of operating strategy is also analyzed by replacing battery with super capacitor which results into decreased number of operating mode changes. The proposed operating strategy ensures flexible operating mode changes and efficient operation of all the sources. It improves the performance of system operation, enhancing the stability and decreasing the number of operating mode changes.