Nonlinear Decentralized Feedback Linearizing Controller Design for Islanded DC Microgrids

Abstract

This paper aims to design decentralized controllers for different components in islanded DC microgrids. The major components in the DC microgrid as considered in this paper include a fuel cell, solar photovoltaic (PV) unit, and battery energy storage system (BESS) along with critical and non-critical loads. The main control objective is to maintain the power balance within the DC microgrid through the regulation of the common DC-bus voltage. The controllers are designed based on the dynamical models of the fuel cell, solar PV unit, and BESS. The feedback linearization technique is employed to obtain the control laws, which simplifies the original dynamical models and decouples different components in the form of several subsystems. In this way, the feedback linearization technique allows different components in DC microgrids to achieve the desired control objectives by using only the local information (i.e., in a decentralized manner). The performance of the proposed decentralized controllers for different components is evaluated on a test DC microgrid under different operating conditions. Simulation results demonstrate that the proposed control scheme performs in a much better way as compared to an existing proportional integral controller.

Keywords::

• battery energy storage system
• DC microgrids
• decentralized controller
• feedback linearization
• fuel cell
• power balance
• solar photovoltaic unit

Additional information

Notes on contributors

Md Apel Mahmud

Md Apel Mahmud received his Ph.D. in Electrical Engineering with the best thesis award from the University of New South Wales, Australia in December 2012 and a Bachelor Degree in Electrical Engineering from Rajshahi University of Engineering and Technology (RUET) in 2008 with the University Gold Medal. Currently he is working as a lecturer in electrical & renewable energy engineering at Deakin University, Australia and recently promoted to senior lecturer (effective from January 2018). He also worked as a lecturer in electrical & electronic engineering at Swinburne University of Technology, a research fellow at the University of Melbourne, and a research publication fellow at the University of New South Wales. Over the last seven years, he has published more than 145 research articles including 3 high impact journal papers and he has attracted more than 1 million dollars internal and external grants. According to Google Scholar, his research articles have received more than 1090 citations with an H-index of 19. Apart from this, Dr. Mahmud is actively engaged with different professional organizations. Currently, he is the chair of IEEE Power & Energy Society (PES) Victorian Chapter. He was also listed as program committee members of several IEEE conferences. His research interests include various topics of electric power engineering.

Tushar Kanti Roy

Tushar Kanti Roy received the B.Sc. degree from Rajshahi University of Engineering and Technology, Rajshahi, Bangladesh, in 2008 in Electrical & Electronic Engineering and Master of Engineering by Research from the University of New South Wales, Canberra, Australia, in 2012 in Electrical Engineering. He is currently working toward the Ph.D. degree in the School of Engineering, Deakin University, Australia. His research interests include nonlinear control theory and applications, excitation control, microgrid, renewable energy, and power electronics.

Shama Naz Islam

Shama Naz Islam is a lecturer in Electrical Engineering at Deakin University. In 2015, she completed her Ph.D. from the Australian National University. She has published more than 20 peer-reviewed articles in prestigious journals and conferences. She has received the 2012–2013 IEEE Australia Council best student paper award in WiE category. She has served as the technical program committee chair for Australasian Universities Power Engineering Conference (AUPEC) 2017. She is also working as a coordinator for Women in Power Engineering activities in IEEE VIC section. She is an associate fellow of the higher education academy in UK. Her research interests include device-to-device communication, smart grid communication, IoT for smart energy applications, energy management, renewable powered base stations, and smart grid security.

Sajeeb Saha

Sajeeb Saha received the B.Sc. degree in electrical and electronic engineering from the Khulna University of Engineering and Technology, Bangladesh, in 2005 and the Ph.D. degree from the University of Melbourne, Australia, in 2012. He is currently a lecturer at the Deakin University, Australia. His research interests include power system dynamic modeling, fault detection and mitigation, power system voltage and transient stability, control of AC–DC hybrid microgrid, and fault tolerant control.

Md Enamul Haque

Md Enamul Haque graduated in Electrical and Electronic Engineering from Rajshahi University of Engineering Technology (RUET), Bangladesh, in 1995. He received the M.Eng. degree in electrical engineering from University Technology Malaysia, Malaysia in 1998, and the Ph.D. degree in Electrical Engineering from University of New South Wales (UNSW), Sydney, Australia, in 2002. He has worked for King Saud University, Saudi Arabia, United Arab Emirates University and University of Tasmania, Australia. He is currently working as a senior Lecturer in Renewable and Smart Energy Systems in the School of Engineering, Deakin University, Australia. His research interests include control of variable speed wind turbines, grid integration impact of renewable energy sources, performance enhancement of power system using STATCOM and energy storage, power management of microgrid with wind, photovoltaic, plug-in hybrid vehicle, fuel cell and energy storage, and power electronics applications in renewable energy and power systems.