Decentralized Control Strategy for a Stand-Alone DC Microgrid based on Voltage Droop and Virtual Impedance

Maico S. Lima; Renan R. Almeida; Andrei O. Almeida

doi:10.18618/REP.e202555

Authors

Maico S. Lima Centro Federal de Educação Tecnológica de Minas Gerais https://orcid.org/0009-0000-8336-4931
Renan R. Almeida Centro Federal de Educação Tecnológica de Minas Gerais https://orcid.org/0009-0002-6249-7238
Andrei O. Almeida Centro Federal de Educação Tecnológica de Minas Gerais https://orcid.org/0000-0003-2072-8683

DOI:

https://doi.org/10.18618/REP.e202555

Keywords:

Battery Energy Storage Systems, DC Microgrids, Photovoltaic Systems, Virtual Impedance, Voltage Droop

Abstract

The continuous development of photovoltaic and energy storage systems has enabled the emergence of microgrids, which can operate with alternating or direct current (DC), depending on the components characteristics. Since photovoltaic panels and battery storage systems operate in DC, connecting them via a DC bus simplifies power conversion, especially for DC loads. A key challenge in microgrids is defining an effective control strategy, which may be centralized, decentralized, or distributed. In this sense, the main proposal of this paper consists in the development of a decentralized control strategy for a stand-alone DC microgrid with photovoltaic generation and battery energy storage, using a controlled voltage droop, based on virtual impedance. This paper aims to contribute with the description of the implementation steps of the local controllers, using classical control techniques based on transfer function modelling. In addition, the assembling steps of a low-cost and small-scale DC microgrid prototype are presented. The control approach maintains DC bus voltage within an appropriate range without requiring communication among system components. Moreover, it supports modular expansion by enabling the seamless integration of new generation or storage units. To validate the strategy, a microgrid prototype was developed using a 60~W PV panel, a 12~V, 7~Ah lead-acid battery, and the BOOSTXL-3PhGaNInv evaluation module with a F28379D digital signal controller for converter implementation. Experimental results, including the battery charging process and variations of solar irradiance and load demand, demonstrate the effectiveness and robustness of the proposed control system.

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Author Biographies

Maico S. Lima, Centro Federal de Educação Tecnológica de Minas Gerais

holds a degree in Control and Automation Engineering (2020) and a Master's degree in Automation and Systems (2024) from the Federal Center for Technological Education of Minas Gerais (CEFET-MG). Since 2015, he has worked as a laboratory technician at CEFET-MG, Campus Leopoldina.

Renan R. Almeida, Centro Federal de Educação Tecnológica de Minas Gerais

is Electrical Technician (2021) and he is currently undergraduate student of Control and Automation Engineering, since 2019, both at Federal Center for Technological Education of Minas Gerais (CEFET-MG), Campus Leopoldina.

Andrei O. Almeida, Centro Federal de Educação Tecnológica de Minas Gerais

received the B.S., M.Sc., and Ph.D. degrees in Electrical Engineering from the Federal University of Juiz de Fora (UFJF), MG, Brazil, in 2017, 2019 and 2023, respectively. Since 2019, he has been professor at Federal Center for Technological Education of Minas Gerais (CEFET-MG), Campus Leopoldina. Since 2023, he has been professor of the Graduate Program in Automation and Systems (PPGAS).

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