Bayesian Optimization-Based Tuning of the Proportional-Integral Controller for Grid-Connected Three-Level NPC Converter

Vitor S. Jorge; Angelo S. Lunardi; Luan A. Sousa; Rodolfo V. Rocha; Renato M. Monaro; Alfeu J. Sguarezi Filho

doi:10.18618/REP.e202605

Authors

Vitor S. Jorge Federal University of ABC https://orcid.org/0009-0008-9995-861X
Angelo S. Lunardi Federal University of ABC
Luan A. Sousa University of São Paulo
Rodolfo V. Rocha Federal University of Mato Grosso
Renato M. Monaro Federal University of São Paulo
Alfeu J. Sguarezi Filho Federal University of ABC https://orcid.org/0000-0001-9981-436X

DOI:

https://doi.org/10.18618/REP.e202605

Keywords:

Power converters, three-level, neutral point clamped, PI controller, Bayesian Optimization

Abstract

Power converters provide energy interface in various applications; in photovoltaics, they interconnect solar panels to the grid, with two‑level inverters being the most common across virtually all power ranges, followed by three‑level neutral point clamped (3LNPC) converters. The proportional-integral (PI) controller is the most commonly employed controller for these converters. This paper proposes the use of Bayesian Optimization (BO) to tune the PI controller for a 3LNPC converter connected to the grid. The optimization algorithm was used to determine the controller’s tuning gains through computational simulation. Subsequently, the PI controller tuned using BO was implemented on an experimental test bench to validate the concept. The performance of the controller tuned with the proposed method was compared to PI controllers adjusted using classical methods widely found in the literature. The test results demonstrated that Bayesian Optimization is straightforward to implement and, when compared to the Genetic Algorithm (GA), it exhibited a more effective and targeted exploration of the search space. This led to superior PI controller tuning, with improved dynamic response and reduced total harmonic distortion relative to the benchmark methods.

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Author Biographies

Vitor S. Jorge, Federal University of ABC

received a B.Sc degree in Electrical Engineering from the Federal University of Pará (UFPA) in Tucuruí, Pará, Brazil, in 2022, and a M.S degree in Applied Computing from the same institution in 2025. Currently pursuing a Ph.D. in the Energy graduate program at the Federal University of ABC (UFABC), Santo André, São Paulo, Brazil. His research interests include control applied to machine drives, power converters and wind energy.

Angelo S. Lunardi, Federal University of ABC

received the degree in electronic engineering from the Instituto Mauá Tecnologia, in 2015, the master’s degree in electrical engineering from the Universidade Federal do ABC (UFABC), with a focus on control research applied to wind power generation, in 2017, and the Ph.D. degree in electrical engineering from the University of São Paulo (USP) with a thesis titled robust predictive control applied to the converter connected to the grid, in 2022. Currently, he is a researcher at the UFABC and works with control systems for renewable energy.

Luan A. Sousa, University of São Paulo

received the B.Sc. degree from the University of São Paulo, São Paulo, Brazil, in 2018. and the M.Sc. degree in 2022 from the University of São Paulo, São Paulo, Brazil. He is currently a researcher in a laboratory at the Inova USP building, Butantã campus, São Paulo, Brazil, where he conducts research in his areas of interest. His research interests include measuring and protection of power systems and distributed generation and renewable energy.

Rodolfo V. Rocha, Federal University of Mato Grosso

received the B.Sc. degree in electrical engineering from the Federal University of Mato Grosso, Cuiabá, Brazil, in 2013; the M.Sc. degree from the São Carlos School of Engineering, University of São Paulo, São Carlos, Brazil, in 2016; and the Ph.D. degree at the Polytechnic School of the University of São Paulo, São Paulo, Brazil, in 2023. He is currently an Adjunct Professor at the Federal University of Mato Grosso, Cuiabá, Brazil. His research interests include measuring, control and protection of power systems, electric machines and power converters.

Renato M. Monaro, Federal University of São Paulo

received the B.Sc. degree in electrical engineering from University of São Paulo, São Carlos, Brazil, in 2007. He received the Ph.D. degree from the same institution. At present, he is an Associate Professor at the University of São Paulo, São Paulo, Brazil. His main research interests include power system control and protection, HVDC-VSC transmission, distributed generation, and renewable energy.

Alfeu J. Sguarezi Filho, Federal University of ABC

received his Master and Doctor degrees in Electrical Engineering from the Faculty of Electrical and Computer Engineering of the University of Campinas (Unicamp) in 2007 and 2010, respectively. Currently, he is Associate Professor at the Federal University of ABC (UFABC). He is a Senior Member of the IEEE and author of several articles in national and international scientific journals and book chapters in the areas of electrical machines, machine drives, electric vehicles, power electronics, and wind and photovoltaic energies.

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