A power conditioning system for a hybrid energy system with photovoltaic and sodium-sulfur battery

A power conditioning system combing with photovoltaic array, sodium-sulfur battery and flywheel energy storage system is presented, which is used to improve the power quality of the low-voltage gird in China. All the three energy sources are connected to the common DC bus by different power electronics interfaces. The functions and specifications of the system are studied, and then the selections of appropriate topologies for those power electronics interfaces are investigated in details.