An online control strategy for a modular DC coupled hybrid power system

This paper describes how different power sources of a hybrid power system may be connected together through a DC bus and then to a grid through a main inverter in such a way that a decoupling between the state variables of the power sources and the state variables of the grid is achieved. A layout showing such a structure will be presented, and an online control strategy for this layout will be developed to show that it is modular, expandable and easily controllable. The behavior of such a structure under different load and meteorological conditions will be investigated by applying the developed control strategy to a simulation model. Moreover, a PV/battery hybrid power system was successfully built up including control functions for the system management. These control functions have been developed and integrated into a standard industrial soft PLC terminal. Finally, the results of the simulation and experimental case study will be introduced and discussed.