@article{song_huang_2010, title={Fault-Tolerant Design and Control Strategy for Cascaded H-Bridge Multilevel Converter-Based STATCOM}, volume={57}, ISSN={["1557-9948"]}, DOI={10.1109/tie.2009.2036019}, abstractNote={Cascaded H-bridge multilevel converter (CHMC) is a promising topology for flexible ac transmission systems such as static synchronous compensator (STATCOM) applications. Attention was drawn to the issue of converter reliability due to the large number of power devices used in CHMC applications. This paper proposed an effective fault-tolerant strategy by using H-bridge building block (HBBB) redundancy in CHMC-based STATCOM. The operating principle and the control strategy of the fault tolerance are proposed and discussed. The controller design consideration for the fault-tolerant STATCOM is presented. The proposed fault-tolerant control strategy is implemented on a seven-level CHMC-based STATCOM simulation platform and a five-level CHMC-based STATCOM hardware prototype. Simulation and experimental results are illustrated to verify the feasibility of the proposed fault-tolerant design with the HBBB redundancy.}, number={8}, journal={IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS}, author={Song, Wenchao and Huang, Alex Q.}, year={2010}, month={Aug}, pages={2700–2708} }
 @inproceedings{liu_p._g._c._huang_langston_steurer_litzenberger_anderson_adapa_et al._2009, title={Controller hardware-in-the-loop validation for a0 10 MVA ETO-based STATCOM for wind farm application}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-72449158355&partnerID=MN8TOARS}, DOI={10.1109/ecce.2009.5316033}, abstractNote={This paper reports experimental validation of a Static Synchronous Compensation (STATCOM) by controller hardware-in-the-loop (CHIL) testing with a real-time digital simulator (RTDS). The controller is designed and developed for a 10 MVA STATCOM for voltage regulation at the PCC of a 50 MW wind farm connected to a 69kV utility grid. Emitter Turn-off (ETO) thyristors are switching devices in the multilevel inverter. The STATCOM controller was developed for a cascade multilevel inverter and has been validated on a laboratory test-bench. The CHIL testing of the controller is done with detailed scaled model of the 50 MW wind farm and 69kV utility system. The experimental results from the RTDS for both steady state and dynamic changes in the STATCOM output validate the STATCOM controller design and performance.}, booktitle={2009 IEEE Energy Conversion Congress and Exposition, ECCE 2009}, author={Liu, Y. and P., Liang Z. and G., Song Z. and C., Bhattacharya W. and Huang, S. and Langston, A. and Steurer, J. and Litzenberger, M. and Anderson, W. and Adapa, L. and et al.}, year={2009}, pages={1398–1403} }
 @inproceedings{huang_liu_chen_li_song_2009, title={Emitter turn-off (ETO) thyristor, ETO light converter and their grid applications}, DOI={10.1109/pes.2009.5275226}, abstractNote={In today's electric power system, solid state power electronics technology plays more and more important roles and the demand for mega-watt level power ratings is increasing. The development of mega-watt power converters strongly depends on the state-of-the-art of power semiconductor technology, cooling technology and digital controller. The authors have been involved in the development of the Emitter Turn-Off (ETO) thyristor, an emerging power semiconductor switch for high power applications. Packed with advanced features as well as superior performance, ETO based power electronics systems are very attractive for various grid applications. In this paper, the authors will present the ETO device, ETO Light converter that are under development at the NSF FREEDM Systems Center. Moreover, the authors will explain how these developments will facilitate grid applications: static synchronous compensator (STATCOM) without/with energy storage, direct connection of wind turbine, High Voltage Direct Current (HVDC) application, power flow control and solid-state circuit breaker and current limiter.}, booktitle={2009 ieee power & energy society general meeting, vols 1-8}, author={Huang, A. and Liu, Y. and Chen, Q. and Li, J. and Song, W. C.}, year={2009}, pages={1861–1868} }
 @inproceedings{song_zhou_liang_bhattacharya_huang_2009, title={Modeling and control design of distributed power flow controller based-on per-phase control}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-72449137681&partnerID=MN8TOARS}, DOI={10.1109/ecce.2009.5316307}, abstractNote={The distributed power flow controller (DPFC) based-on Emitter Turn-Off (ETO) light converter is one newly proposed solid state power electronics technology based Flexible AC Transmission System (FACTS) devices which is effective to control the active power flow through the transmission lines. This modular DPFC has low cost, high reliability and makes it possible to have the transformerless connection to the existing power grid. In this paper, the development and analysis of modeling techniques and feedback schemes based on per phase control of DPFC are proposed. The simulation results and experimental results show the consistency of the propose model and the feasibility of the feedback control design for the DPFC per-phase operation.}, booktitle={2009 IEEE Energy Conversion Congress and Exposition, ECCE 2009}, author={Song, W. and Zhou, X. and Liang, Z. and Bhattacharya, Subhashish and Huang, A.Q.}, year={2009}, pages={3262–3267} }
 @article{liu_huang_song_bhattacharya_tan_2009, title={Small-Signal Model-Based Control Strategy for Balancing Individual DC Capacitor Voltages in Cascade Multilevel Inverter-Based STATCOM}, volume={56}, ISSN={["1557-9948"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-67649366309&partnerID=MN8TOARS}, DOI={10.1109/TIE.2009.2017101}, abstractNote={This paper presents a new feedback control strategy for balancing individual DC capacitor voltages in a three-phase cascade multilevel inverter-based static synchronous compensator. The design of the control strategy is based on the detailed small-signal model. The key part of the proposed controller is a compensator to cancel the variation parts in the model. The controller can balance individual DC capacitor voltages when H-bridges run with different switching patterns and have parameter variations. It has two advantages: 1) the controller can work well in all operation modes (the capacitive mode, the inductive mode, and the standby mode) and 2) the impact of the individual DC voltage controller on the voltage quality is small. Simulation results and experimental results verify the performance of the controller.}, number={6}, journal={IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS}, author={Liu, Yu and Huang, Alex Q. and Song, Wenchao and Bhattacharya, Subhashish and Tan, Guojun}, year={2009}, month={Jun}, pages={2259–2269} }
 @article{liu_bhattacharya_song_huang_2008, title={Control Strategy for Cascade Multilevel Inverter based STATCOM with Optimal Combination Modulation}, ISBN={["978-1-4244-1667-7"]}, ISSN={["0275-9306"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-52349084808&partnerID=MN8TOARS}, DOI={10.1109/pesc.2008.4592734}, abstractNote={Static synchronous compensation (STATCOM) is a flexible AC transmission system (FACTS) device connected in shunt to the network for generating or absorbing reactive power. The STATCOM is used to regulate voltage, control power factor and stabilize power flow. The transformerless STATCOM is attractive due to low cost and power losses. Cascaded multilevel inverters are viable topologies for the transformerless STATCOM since each power semiconductor device only sustains low voltage. To meet IEEE 519 standard and keep low switching frequency, an optimal combination modulation strategy is used, which leads to some challenges in designing the controller, such as extra switching and the balancing of individual dc capacitor voltages. In this paper, the design of the controller is specified. Simulation results and experimental results are shown to verify the performance of the proposed control strategy.}, journal={2008 IEEE POWER ELECTRONICS SPECIALISTS CONFERENCE, VOLS 1-10}, author={Liu, Yu and Bhattacharya, Subhashish and Song, Wenchao and Huang, Alex Q.}, year={2008}, pages={4812–4818} }