A Generalized Switched-Capacitor Modular Multilevel Inverter Topology for Multiphase Electrical Machines with Capacitor-Voltage Self-Balancing Capability

TL;DR

This paper introduces a flexible, scalable switched-capacitor inverter topology capable of generating multiple voltage levels, balancing capacitor voltages, and supporting multiphase loads with reduced cost and volume.

Contribution

A novel generalized inverter topology that enables variable output voltages, easy expansion, and inherent capacitor voltage balancing for multiphase electrical machines.

Findings

Topology supports a wide range of output voltages.

Capacitor voltage balancing is inherently achieved.

Simulation results validate the proposed design.

Abstract

Recent research on multilevel inverters shows exciting properties, including the potential to generate multiple output voltages and integrated voltage boosting. However, most presented inverter topologies have a restricted number of output voltage levels and limited output voltage boosting ratio. In addition, balancing the voltage of capacitors in multilevel converters is very important and should be considered in the topology or control method. This paper describes a generalized switched-capacitor circuit topology for multilevel dc-to-ac inverters that can be developed for the desired output voltage levels. Also, the maximum ac output voltage can vary from values much lower than the dc input voltage to several times of it depending on the design requirement. High-voltage dc input and ac output could be handled using low-voltage capacitors, which substantially decreases overall cost and volume. The proposed topology further allows for easy expansion through stackable circuits for multiple load phases. It has an inherent capacity for balancing the voltage of capacitors. To validate the feasibility and practicality of this concept, we provide circuit descriptions, control strategies, design recommendations, and pertinent simulation findings for the suggested inverter topology.