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Rigorous Systems Research Group (RSRG) Seminar

Wednesday, February 21, 2024
4:00pm to 5:00pm
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Annenberg Center
Single-phase inverter control techniques for interfacing renewable energy sources with micro-grid – Parallel/Series connected inverter topologies
Sanjib Kumar Panda, Associate Professor and Director, Power & Energy Research Group, Department of Electrical and Computer Engineering, National University of Singapore,

Location: Annenberg 223 and Zoom

Abstract: Renewable energy sources (RESs) have been receiving significant attention recently worldwide as a sustainable alternative type of energy supply in the energy mix. Inverters are being used to convert the dc voltage into ac voltage before being injected into the grid or isolated loads.

In this presentation, a novel current control technique is proposed to control both active and reactive power flow from a renewable energy source feeding a micro-grid system through a single-phase parallel connected inverter. The parallel connected inverter ensures active and reactive power flow from the grid with low current THD even in the presence of non-linear load. A p-q theory-based approach is used to find the reference current of the parallel connected converter to ensure desired operating conditions at the grid terminal. The proposed current controller is simple to implement and gives superior performance over the conventional current controllers such as rotating frame PI controller or stationary frame Proportional Resonant (PR) controller. The stability of the proposed controller is ensured by direct Lyapunov method. A new technique based on the Spatial Repetitive Controller (SRC) is also proposed to improve the performance of the current controller by estimating the grid and other periodic disturbances. Detailed experimental results are presented to show the efficacy of the proposed current control scheme along with the proposed non-linear controller to control the active and reactive power flow in a single-phase micro-grid under different operating conditions.

For the series-connected inverter compensating voltage works in such a way that, irrespective of any type of disturbances in the micro-grid voltage (such as sag, swell or harmonic distortions), the load voltage is maintained at its rated voltage level with low THD in voltage. The proposed control strategy also facilitates a specific amount of active power flow (from renewable energy source) to the load irrespective of the micro-grid voltage condition. The rest of the load power is supplied by the micro-grid. To facilitate this control strategy a Spatial Repetitive Controller (SRC) is proposed and implemented in micro-grid phase ( θ ) domain to make the controller independent of the micro-grid frequency. The proposed controller ensures dynamic stability of the system even if there is a sudden change in the micro-grid frequency. Detailed experimental results are presented to show the efficacy of the proposed series inverter system along with the controller under different operating conditions.

Bio: Sanjib Kumar Panda (S'86-M'91-SM'01-F'2021) received B. Eng. Degree from the South Gujarat University, India, in 1983, M.Tech. degree from the Indian Institute of Technology, Banaras Hindu University, Varanasi, India, in 1987, and the Ph.D. degree from the University of Cambridge, U.K., in 1991, all in electrical engineering. He was the recipient of the Cambridge-Nehru Scholarship and M. T. Mayer Graduate Scholarship during his PhD study (1987-1991). Since 1992, he has been holding a faculty position in the Department of Electrical and Computer Engineering, National University of Singapore and currently serving as an Associate Professor and Director of the Power & Energy Research Area. Dr. Panda has published more than 450 peer-reviewed research papers, co-authored one book and contributed to several book chapters, holds six patents and co-founder of three start-up companies. His research interests include high-performance control of motor drives and power electronic converters, condition monitoring and predictive maintenance, building energy efficiency enhancement etc. He is serving as an Associate Editor of several IEEE Transactions e.g. Power Electronics, Industry Applications, Energy Conversion, Access and IEEE Journal of Emerging and Selected Topics in Power Electronics. He was the Chair of the IEEE PELS Technical Committee -12 (TC-12): Energy Access and Off-grid Systems (2021-2023).

For more information, please contact Yiheng Lin by email at [email protected].