Multimodule DC-DC Converters for High-Voltage High-Power Renewable Energy Sources

Abstract

High-voltage high-power DC-DC converters are an essential requirement for constructing HVDC networks since voltage levels, as well as the network configuration, are not standardized. Accordingly, this paper focuses on multimodule DC-DC converter-based Dual Active Bridge (DAB) for high-voltage high-power renewable energy sources such as PV plant and wind farms. The modularity concept is applied to the entire stage and not only limited to the power electronic stage. In addition, higher switching frequency in the AC link can be achieved, which would result in significant weight and size reduction. To study the dynamic behavior of such converters, the small-signal analysis for a four-module Input-Series Input-Parallel Output-Series (ISIPOS) DC-DC converter along with its frequency response is delivered. In addition, sensitivity analysis for the ISIPOS converter is presented to study the behavior of the converter when its parameters change. Moreover, different multimodule DC-DC converter-based DAB scenarios for different purposes are presented. To clarify, the main aim of this paper is studying the small-signal analysis of a four-module ISIPOS DC-DC converter as well as presenting different scenarios for multimodule DC-DC converters. The two studied scenarios can be summarized in: connecting a high-voltage high-power PV park to a high-voltage transmission and connecting two HVDC transmission with different voltage levels.