Performance Comparison of 2L-VSC, 3L-NPC, and 3L-MMC Converter Topologies for Interfacing Grid-Connected Systems

Nowadays, power converters play a fundamental role in the conditioning and processing of active and reactive power, and are directly related to power quality indexes. In this sense, new multi-level converter topologies have been integrated in order to provide higher power processing capacity with lower harmonic distortion, switch stress, heating, and losses. The use of these structures compared to conventional two-level converters is especially suitable for high power of the order of megawatt. Considering the relevance of this approach, this paper presents a comparative performance analysis among the conventional two-level topology (2L-VSC) and two multilevel topologies in a grid-connected system: neutral point clamped (NPC) and modular multilevel converter (MMC). Simulation test results present the impacts on voltages and currents for the switches and the whole system, as well as the evaluation of the total harmonic distortion (THD) in order to highlight the crucial points of each topology for this kind of application.