Decentralized Control for Multiple Network-Forming Inverters in a Solar PV-BESS Based Standalone Microgrid System

Abstract

Abstract—This research paper focuses on decentralized control of an AC microgrid in standalone mode. The microgrid includes three solar PV arrays accompanied by three battery energy storage systems (BESS), utilizing renewable distributed energy resources (DERs). The connection between each DER system and the microgrid is established through a network-forming three-phase voltage source inverter (VSI). The microgrid’s operation is regulated using modified droop control, incorporating virtual impedance and feed-forward derivative in primary control, along with a phase-locked loop (PLL) system for inverter synchronization. A master-slave control configuration is employed between the VSIs to mitigate voltage amplitude and frequency deviations induced by primary control. These enhancements ensure smooth power distribution and maintain voltage amplitude and frequency within specified limits across different operational scenarios. Control operations are performed in a stationary frame ($\alpha -\beta$ frame) using Clarke’s transformation, and PR controllers regulate VSI’s output voltage and current. The research paper shows the effectiveness of controlled microgrid operations using MATLAB/Simulink software in various conditions including intermittent PV system behavior, load dynamics, and DER connection/disconnection challenges. Simulation results show that the proposed approach enhances stability and performance of the microgrid system, especially in managing power fluctuations and maintaining a constant frequency response.

Keywords:

• AC mircogrid
• decentralized control
• droop control
• network-forming inverters
• PLL synchronization
• solar PV-BESS
• virtual impedance

ACKNOWLEDGMENT

The authors express their thanks to the Ministry of Education, Government of India, for funding a scholarship during Karan Singh Joshal’s Ph.D.

DISCLOSURE STATEMENT

No potential conflict of interest was reported by the author(s).

Additional information

Notes on contributors

Karan Singh Joshal

Karan Singh Joshal is presently engaged in doctoral studies at NIT Srinagar in Jammu and Kashmir, India. He received his B.Tech degree in Electrical Engineering from Jamia Millia Islamia University, Delhi, India, and subsequently completed his Master of Technology (M.Tech) in Control and Instrumentation within the Electrical Engineering Department at MNIT Allahabad, India. With over five years of experience as a Lecturer in Electrical Engineering, his expertise spans various areas, including IoT, smart grid technologies, control of microgrids, and the integration of renewable energy sources.

Neeraj Gupta

Neeraj Gupta is PhD in power systems from Indian Institute of Technology Roorkee, Roorkee, India. He is Senior Member of IEEE. Previously he was with Thapar University, Adani Institute and NIT Hamirpur. Presently, he has been working as an Assistant professor with the Electrical Engineering Department, National Institute of Technology, Srinagar, J&K, India. He earned recognition in 2021 and 2023 as one of the top 2% scientists database in the field of energy curated by Stanford University researchers. His research interests include uncertainty quantification of power system, probabilistic power system, solar, wind, and electric vehicle technologies, Artificial intelligence, Machine learning, prediction etc.