Graphical analysis and control of cascaded H-bridge multilevel inverter using Clarke transformation with neutral-Shift strategy under non-ideal conditions

Lingom, P. M., Song-Manguelle, J., Libouga, I. O., Doumbia, M. L. et Agamloh, E. (2024). Graphical analysis and control of cascaded H-bridge multilevel inverter using Clarke transformation with neutral-Shift strategy under non-ideal conditions. IEEE Journal of Emerging and Selected Topics in Power Electronics, 13 (3). pp. 3311-3323. ISSN 2168-6785 DOI 10.1109/JESTPE.2024.3523846

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Résumé

Abstract

This paper proposes a graphical approach using a 3D space vector representation to diagnose the unbalanced operation of a three-phase cascaded H-bridge (CHB) inverter operating under non-ideal conditions. Under ideal conditions, the application of the Clarke transformation to the inverter voltage phasor results in a circular trajectory within the stationary and orthogonal (αβ)-frame, enabling the inverter to supply balanced three-phase phase/line voltages and currents to the load. In contrast, when non-ideal conditions arise, such as DC voltage imbalances among the bridges or failed cells, the Clarke transformation of the inverter voltage phasor forms an elliptical path, leading to unbalanced operation. This paper discusses and highlights the characteristic differences between inverter-balanced and unbalanced operation modes. Additionally, a generalized neutral-shift method has been suggested to address unequal DC voltage sources simultaneously and failed cells without differentiation. The proposed control strategy ensures the inverter maintains balanced line-to-line voltages and currents, even when its phase voltages remain unbalanced. Simulation and experimental results from a three-cell (per phase) CHB inverter with a symmetrical RL load are provided to validate the effectiveness of the proposed approach. Finally, the study explores the impact of non-ideal conditions on modifying inverter voltage and current spectra.

Type de document:	Article
Mots-clés libres:	Inverters Voltage Pulse width modulation Vectors Modulation Voltage control Topology Batteries Trajectory Three-dimensional displays
Date de dépôt:	27 nov. 2025 19:01
Dernière modification:	27 nov. 2025 19:03
Version du document déposé:	Post-print (version corrigée et acceptée)
URI:	https://depot-e.uqtr.ca/id/eprint/12437

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