Multi-level inverters have increasingly gathered interest over the past decade due to their increased efficiency and power density for demanding applications such as power generation from renewable energy sources and high-performance drive and traction systems. For lower power systems in the kW range, gate driving circuitry can occupy area and volume much larger than that of the semiconductor devices, which is especially challenging in high device count topologies, thus prohibiting increase in power density. In an attempt to minimize such circuitry, this paper proposes an implementation of an 11-level single phase inverter, which can be extended to N-levels, with minimal driving requirements in terms of signal and power isolation. The concept is then validated through an 850 W laboratory prototype, reaching a peak efficiency of 97.1% and power density of over 4 kW/L.

The renewable energy revolution drives advancements in power conversion with the DC/AC inverter stage at the forefront. Multi-level inverters (MLIs) produce more output voltage levels than conventional two-level inverters, which allows for smaller passive filters and improved dV/dt performance, but they require complex driving strategies and an increased number of isolation points, a major bottleneck. This paper addresses these limitations by introducing an expandable MLI architecture that maintains a constant number of two isolation points regardless of output levels. This is achieved by combining the multi-terminal bidirectional switch (MTBDS), a bidirectional switch topology, with the cascaded bipolar switched cell converter (CBSC) and a novel driving scheme that replaces conventional dead-time insertion with a four-step commutation scheme. The viability of the concept was investigated with simulations and experimentally verified with a five-level 1 kW prototype that reached 95.5% efficiency at full load.

To meet the ever-increasing demand for energy dense, compact and lightweight power inverters, a fundamentally different approach must be taken in energy conversion. Inspired by the signal-level digital to analog conversion, the goal of this work is to introduce and demonstrate a solid-state multi-terminal selector switch, capable of switching between different voltages via a single reference electrode, practically minimizing the signal and power isolation requirements that plague today’s multi-level inverter structures and thus opening the road for truly N-level capable and scalable power converters.

Inverter surge current capability has become increasingly more important in today’s grid infrastructure as synchronous generation is being replaced by inverter-based resources. Grid strength challenges such as limited voltage support and control instabilities have risen due to the surge current boundaries imposed by the thermal limitations of the conventional semiconductors used in inverters. The goal of this paper is to investigate and compare the surge current robustness of various discrete power transistor technologies, such that the capabilities of commercial inverters can be pushed further to facilitate a seamless transition to increased integration of renewable energy sources