Integrated Multiport DC-DC and Multilevel Converters for Multiple Renewable Energy Source Integration

Abstract

This research introduces an innovative converter system which has been developed to seamlessly incorporate multiple sources of renewable energy into both DC and AC grids. The integration of multiple energy sources is made possible through the utilization of a unique converter system that combines a multiport DC converter topology with a multilevel inverter topology, while maintaining a low component count and hence increased overall power density and efficiency for the proposed converter system. Unlike previous literature, where each energy source needs a separate DC converter and a two-level converter is used for DC to AC conversion, this converter system features buck-boost operation, superior power quality characteristics, and fewer components. The system suggests the implementation of a DC link voltage balancing technique that relies on an auxiliary circuit to achieve equilibrium in the voltage on the DC link, as a possible substitute to the more complicated control-based balancing scheme. The operational integrity of the converter system is assessed through rigorous numerical simulations and experimentally validated using OPAL-RT’s OP5700 hardware-in-the-loop (HIL) implementation platform as well as an in-house experimental test setup.