Design and Operation Control of “Photovoltaic-Battery-SOFC” Hybrid Power Generation System

Photovoltaic power generation has problems such as randomness, intermittentness, and insufficient power supply. A small PV-Battery-SOFC” hybrid power generation system was designed to solve these problems. The system consists of photovoltaic arrays (PV), high-temperature Solid Oxide Fuel Cell (SOFC), battery, DC load, power conversion circuit, PLC controller and other components. A new type of SOFC was used as a reliable supplementary power supply for the photovoltaic array. The control unit adopted Delta DVP series PLC as the controller and the voltage and current control method to collect and feedback the system operation data in real-time, which can automatically monitor the system current and voltage to make them work in a stable state. According to the working characteristics of each component unit, the control strategy of the corresponding interface conversion circuit was developed. In this way, the PLC controller completed the intelligent switching of multiple operating modes of the system, and also realized the energy balance management between photovoltaic array, high-temperature SOFC and battery. Through the analysis of the experimental data, it is shown that the multiple micro-power sources in PV-Battery-SOFC” hybrid power generation system can be operated and switched in a safe and stable state. Thus, the rapid and accurate management of various micro-power sources in the system can be realized and the stable operation and high-efficiency control of the power generation system also can be ensured. Finally, the results fully demonstrate that this research can help to control the operation of distributed power supply and energy storage unit, and contribute to constructing multi-energy complementary microgrid in rural and remote areas and off-grid power supply.