A multilevel voltage-source inverter with separate DC sources for static VAr generation

TLDR

The inverter is proposed to enable high‑voltage, high‑power applications such as FACTS, SVG, and power‑line conditioning by providing a new multilevel voltage‑source topology with separate DC sources. It consists of (M‑1)/2 single‑phase full bridges, each powered by its own DC source, and its performance is evaluated through analysis, simulation, and experiment in an SVG system. The device generates near‑sinusoidal voltage with only one switching per cycle, reduces size, weight, and component count relative to conventional designs, and its superiority is confirmed by the analysis, simulation, and experimental results.

Abstract

A new multilevel voltage-source inverter with separate DC sources is proposed for high-voltage, high-power applications, such as flexible AC transmission systems (FACTS) including static VAr generation (SVG), power-line conditioning, series compensation, phase shifting, voltage balancing, fuel cell, and photovoltaic utility systems interfacing, etc. The new M-level inverter consists of (M-1)/2 single-phase full bridges in which each bridge has its own separate DC source. This inverter can generate almost sinusoidal waveform voltage with only one time switching per cycle as the number of levels increases. It can solve the size-and-weight problems of conventional transformer-based multipulse inverters and the component-counts problems of multilevel diode-clamp and flying-capacitor inverters. To demonstrate the superiority of the new inverter, an SVG system using the new inverter topology is discussed through analysis, simulation, and experiment.