Dual Converters Coupled to Thermal Grid for Simultaneous Control on Regulation and Compensation in a Hybrid AC-DC Network

Abstract

In conventional, radial, AC distribution system, the unbalances in load voltages & source currents at distributor junction (DJ) may affect the quality of power. Mostly, a single converter is employed to address any one unbalance at an instant and the power transfer during critical conditions is not met out effectively. To overcome this, an effective, coordinated operation of dual converters (C1&C2) in a hybrid AC-DC network coupled to thermal grid (Electro-thermal network) for meeting the heating demand of a community, is enunciated in this paper. The DC micro grid (DCM) is energized by renewable for serving the community’s heating and public electrical demands. Irrespective of source voltage & load conditions, the C1&C2 aim at voltage regulation & load compensation at DJ, respectively. Also, the control exhibits around 3% THD which is well within the standard levels. During any source outage/less power production, DCM supplies power to loads through inversion. An uninterrupted, quality power to loads at DJ by the dual converters, irrespective of source voltage & load variations along with a conservative approach through the thermal grid, claims the prime merit of the setup. Various unbalance cases including voltage sag & swell, no source & excess DCM power cases are examined through a supervisory control algorithm for analyzing the effectiveness of the control & system flexibility. The effective performance of the above is verified in real time using Hardware-in-Loop approach through DS1104 (dSPACE Controller) and OP4510 (Opal-Real Time) Controllers.

Keywords:

• thermal grid
• regulation
• inversion
• compensation

Acknowledgments

The authors thank the authorities of National Institute of Wind Energy (NIWE), Chennai, an autonomous R&D division under Ministry of New & Renewable Energy, India for providing the required solar profile data and supporting this work. The authors also acknowledge TNSCST -YSFS award for collaboration of authors.

Disclosure Statement

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

Additional information

Notes on contributors

U. Sowmmiya

U. Sowmmiya obtained her B.E degree in Electrical and Electronics Engineering and M.E degree with specialization in Power Electronics and Drives from Anna University, Chennai. She also obtained her PhD degree from College of Engineering, Guindy, Anna University, Chennai. She is awarded a Post-Doctoral Fellowship under Young Scientist Fellowship Scheme of TNSCST at National Institute of Technology, Karnataka. Presently, she is working as an Associate Professor in the Electrical and Electronics Engineering Department of SRM Institute of Science and Technology, Kattankulathur. She has 12 years of teaching/research experience. Her current research interests are grid integration of renewable sources, condition monitoring, power transfer in wind energy conversion systems and power quality issues in propulsion systems. She completed TNSCST funded project titled “Control and Harmonic Analysis of Wind Energy Conversion System”. Currently, the on-going projects are funded by MoES to about Rs. 48 lakhs on “Digital Twin for manned Submersible” and by AISTDF to about Rs. 24.7 lakhs on “Intelligent Fingerprint Model for DFIG based Wind energy Conversion System”. She has 21 publications in refereed science indexed international journals/conferences to her credit. She has authored two book chapters in indexed books. She was awarded with high impact journal award under Wenlock Endowment Scheme by Anna University, Young researcher award by Marina Labs, Research Excellence award by Institute of scholars and Strategies in Green Excellence award by CENR, SRM. She is a life member of Indian Society of Technical Education, ISTE, member of IEEE, IEI and IET.

M. S. Keerthana

M. S. Keerthana holds a Doctorate degree in Electrical and Electronics Engineering and Master’s degree in Power Engineering and Management from College of Engineering, Guindy, Chennai. Her areas of interest include power converters for battery charging, thermal energy storage and power quality.

A. Karthikeyan

A. Karthikeyan (Senior Member, IEEE) received the B.E. degree from Bharathidasan University, Tiruchirappalli, India, in 2002, and the M.S. (by research) and Ph.D. degrees from the National Institute of Technology, Tiruchirappalli, India, in 2008 and 2013, respectively, all in electrical and electronic engineering. He is currently an Associate Professor with the Department of Electrical and Electronics Engineering, National Institute of Technology, Surathkal, India. His research interests include design of power converter for drives, renewable energy systems and power conditioning.

K. Padmanathan

K. Padmanathan is currently working as Director Research and Incubation Cell at Agni College of Technology. He has graduated in engineering with a Bachelor's degree in Electrical and Electronics Engineering in 2006, Master’s degree in Power Electronics and Drivers and a Doctorate in Renewable Energy from the College of Engineering Guindy at Anna University, Chennai, and Tamilnadu, India, in 2008 and 2018, respectively. He has 16 years of experience in industries and educational institutions doing research, consulting, teaching, and administration. He possesses a vast amount of knowledge and deep skills in numerous industries due to his career in academia, industry, and research. He has over 40 outstanding and unique research publications. He has completed numerous energy audit projects as well as many turnkey energy projects. The Office of the Controller General of Patent, Design, and Trade Marks, Department for Promotion of Industry and Internal Trade, Government of India, has granted him four patents with intellectual property rights. In the fields of green mobility and renewable energy, he founded his startups, EVNEXUS Private Limited and NestLives Private Limited. He is also the member of MIE and MISTE.