This study presents a novel three‐level neutral‐point‐clamped quasi‐Z‐source inverter in the single‐stage buck‐boost multilevel inverter family. The topology was derived by combining the properties of the quasi‐Z‐source network with those of a three‐level neutral point clamped inverter. It features such advantages as low voltage stress of the switches, single‐stage buck‐boost power conversion, continuous input current, short‐circuit withstandability and low total harmonic distortion of the output voltage and current. The authors present a steady state analysis of the topology along with a special modulation technique to distribute shoot‐through states during the whole fundamental period. Component design guidelines for a single‐phase case study system are described. All the findings have been confirmed by simulations and experiments. The topology could be recommended for applications requiring continuous input current, high input voltage gain and enhanced quality of the output voltage.

DC microgrids initiated the change of a paradigm regarding the concept about electrical distribution networks, especially in the context of the distributed generation associated to renewable energies. However, this new reality opens a new area of research, in which several aspects must be carefully studied. Indeed, the bipolar design is one of the principal dc microgrid configurations considering its characteristic wiring. Although holding many promising advantages, the bipolar dc microgrid has a tendency towards voltage and current imbalances due to the unequal distribution of the loads and generators between the two poles. Thus, specific power-electronic-based solutions are required to ensure the balance of these dc microgrids. Within this frame, this article gives a comprehensive review of the multiple architectures and power electronic topologies proposed to mitigate/eliminate this undesired condition. The following provides an insightful classification and discussion with the pros and cons of these solutions. This work can serve as a timely review for researcher/engineers who want to enter the voltage balancing field in the bipolar dc grids and promote the innovation of their power-electronics-enabled solutions.

Impedance-source networks are an increasingly popular solution in power converter applications, especially in single-stage buck-boost power conversion to avoid additional front-end dc-dc power converters. In the survey papers published, no analytical comparisons of different topologies have been described, which makes it difficult to choose the best option. Thus, the aim of this paper is to present a comprehensive analytical comparison of the impedance-source-based buck-boost inverters in terms of passive component count and semiconductor stress. Based on the waveform of the input current, i.e., with or without a transformer, and with or without inductor coupling, the impedance-source converters are classified. The main criterion in our comprehensive comparison is the energy stored in the passive elements, which is considered both under constant and predefined high frequency current ripple in the inductors and the voltage ripple across the capacitors. Two-level and multilevel solutions are described. The conclusions provide a “one-stop” information source and a selection guide of impedance-source-based buck-boost inverters for different applications.