@article{shirsat_muthukaruppan_hu_paduani_xu_song_li_lu_baran_lubkeman_et al._2023, title={A Secure and Adaptive Hierarchical Multi-Timescale Framework for Resilient Load Restoration Using a Community Microgrid}, volume={14}, ISSN={["1949-3037"]}, url={https://doi.org/10.1109/TSTE.2023.3251099}, DOI={10.1109/TSTE.2023.3251099}, abstractNote={Distribution system integrated community microgrids (CMGs) can partake in restoring loads during extended duration outages. At such times, the CMGs are challenged with limited resource availability, absence of robust grid support, and heightened demand-supply uncertainty. This paper proposes a secure and adaptive three-stage hierarchical multi-timescale framework for scheduling and real-time (RT) dispatch of CMGs with hybrid PV systems to address these challenges. The framework enables the CMG to dynamically expand its boundary to support the neighboring grid sections and is adaptive to the changing forecast error impacts. The first stage solves a stochastic extended duration scheduling (EDS) problem to obtain referral plans for optimal resource rationing. The intermediate near-real-time (NRT) scheduling stage updates the EDS schedule closer to the dispatch time using new obtained forecasts, followed by the RT dispatch stage. To make the decisions more secure and robust against forecast errors, a novel concept called delayed recourse is designed. The approach is evaluated via numerical simulations on a modified IEEE 123-bus system and validated using OpenDSS and hardware-in-loop simulations. The results show superior performance in maximizing load supply and continuous secure distribution network operation under different operating scenarios.}, number={2}, journal={IEEE TRANSACTIONS ON SUSTAINABLE ENERGY}, author={Shirsat, Ashwin and Muthukaruppan, Valliappan and Hu, Rongxing and Paduani, Victor Daldegan and Xu, Bei and Song, Lidong and Li, Yiyan and Lu, Ning and Baran, Mesut and Lubkeman, David and et al.}, year={2023}, month={Apr}, pages={1057–1075} }
 @article{paduani_yu_xu_lu_2022, title={A Unified Power-Setpoint Tracking Algorithm for Utility-Scale PV Systems With Power Reserves and Fast Frequency Response Capabilities}, volume={13}, ISSN={["1949-3037"]}, url={https://doi.org/10.1109/TSTE.2021.3117688}, DOI={10.1109/TSTE.2021.3117688}, abstractNote={This paper presents a fast power-setpoint tracking algorithm to enable utility-scale photovoltaic (PV) systems to provide high quality grid services such as power reserves and fast frequency response. The algorithm unites maximum power-point estimation (MPPE) with flexible power-point tracking (FPPT) control to improve the performance of both algorithms, achieving fast and accurate PV power-setpoint tracking even under rapid solar irradiance changes. The MPPE is developed using a real-time, nonlinear curve-fitting approach based on the Levenberg-Marquardt algorithm. A modified adaptive FPPT based on the Perturb and Observe technique is developed for the power-setpoint tracking. By using MPPE to decouple the impact of irradiance changes on the measured PV output power, we develop a fast convergence technique for tracking power-reference changes within three FPPT iterations. Furthermore, to limit the maximum output power ripple, a new design is introduced for the steady-state voltage step size of the adaptive FPPT. The proposed algorithm is implemented on a testbed consisting of a 500 kVA three-phase, single-stage, utility-scale PV system on the OPAL-RT eMEGASIM platform. Results show that the proposed method outperforms the state-of-the-art.}, number={1}, journal={IEEE TRANSACTIONS ON SUSTAINABLE ENERGY}, publisher={Institute of Electrical and Electronics Engineers (IEEE)}, author={Paduani, Victor Daldegan and Yu, Hui and Xu, Bei and Lu, Ning}, year={2022}, month={Jan}, pages={479–490} }
 @article{awal_tu_xu_lukic_husain_2021, title={Circulating Reactive Power and Suppression Strategies in DC Power Electronics Networks}, ISSN={["1048-2334"]}, DOI={10.1109/APEC42165.2021.9487129}, abstractNote={In DC electrical networks consisting of pulse-width-modulated converters, large circulating reactive power may be caused by parallel resonance among the passive filters and the parasitic elements of the interconnecting power-line cables. Such undesired circulating currents at switching frequencies and their harmonics lead to larger ripple in the network voltage, shorter component lifetime, and increased loss. In this work, the condition for such resonances is derived analytically and two suppression methods, namely, an inductor-capacitor (LC) trap filter and an L-termination filter, are proposed. Through analysis, we demonstrate that the proposed methods can guarantee resonance suppression in a generic DC network consisting of arbitrary N converters. Systematic design rules are developed. The analysis and suppression methods are validated through laboratory experiments.}, journal={2021 THIRTY-SIXTH ANNUAL IEEE APPLIED POWER ELECTRONICS CONFERENCE AND EXPOSITION (APEC 2021)}, author={Awal, M. A. and Tu, Hao and Xu, Bei and Lukic, Srdjan and Husain, Iqbal}, year={2021}, pages={796–803} }
 @article{paduani_song_xu_lu_2021, title={Maximum Power Reference Tracking Algorithm for Power Curtailment of Photovoltaic Systems}, ISSN={["1944-9925"]}, DOI={10.1109/PESGM46819.2021.9638157}, abstractNote={This paper presents an algorithm for power curtailment of photovoltaic (PV) systems under fast solar irradiance intermittency. Based on the Perturb and Observe (P&O) technique, the method contains an adaptive gain that is compensated in real-time to account for moments of lower power availability. In addition, an accumulator is added to the calculation of the step size to reduce the overshoot caused by large irradiance swings. A testbed of a three-phase single-stage, 500 kVA PV system is developed on the OPAL-RT eMEGAsim real-time simulator. Field irradiance data and a regulation signal from PJM (RTO) are used to compare the performance of the proposed method with other techniques found in the literature. Results indicate an operation with smaller overshoot, less dc-link voltage oscillations, and improved power reference tracking capability.}, journal={2021 IEEE POWER & ENERGY SOCIETY GENERAL MEETING (PESGM)}, author={Paduani, Victor and Song, Lidong and Xu, Bei and Lu, Ning}, year={2021} }