Medium-Voltage Multilevel Converters—State of the Art, Challenges, and Requirements in Industrial Applications

TLDR

Increasing power rating by minimizing switching frequency while maintaining power quality remains a key industry challenge. The paper reviews MV multilevel converters and proposes a three‑level building‑block inverter that generates five‑level voltage waveforms. Existing topologies, limitations, and control techniques are analyzed, and the proposed inverter design is described. The suggested inverter operates at very low switching frequency, achieving minimal on‑state and dynamic losses while preserving low harmonic distortion for efficient MV drives.

Abstract

This paper gives an overview of medium-voltage (MV) multilevel converters with a focus on achieving minimum harmonic distortion and high efficiency at low switching frequency operation. Increasing the power rating by minimizing switching frequency while still maintaining reasonable power quality is an important requirement and a persistent challenge for the industry. Existing solutions are discussed and analyzed based on their topologies, limitations, and control techniques. As a preferred option for future research and application, an inverter configuration based on three-level building blocks to generate five-level voltage waveforms is suggested. This paper shows that such an inverter may be operated at a very low switching frequency to achieve minimum on-state and dynamic device losses for highly efficient MV drive applications while maintaining low harmonic distortion.