Integration of batteries into a modular multilevel converter

In this paper the challenges of integrating batteries into the Modular Multilevel Converter are described. For this purpose, the technology of this converter topology is briefly introduced. An overview on already available products of battery energy storage systems is given. Based on that, a control concept for a DC-to-DC converter connecting a battery to a module of the Modular Multilevel Converter is presented. This concept contains an additional energy balancing algorithm. Several operating points of the whole system with integrated batteries are simulated. The paper is topped off with measurement results of a started-up hardware setup that is equipped with emulated DC-to-DC converters.