Special Speaker 1:
Mechanism and Suppression Control of Wideband Oscillations in MMC-HVDC with Offshore Wind Farms
Shanghai Jiao Tong University
Dr. Jing Lyu received his PhD degree from Shanghai Jiao Tong University, Shanghai, China, in 2016. He is currently a Tenure-Track Associate Professor with the Department of Electrical Engineering, Shanghai Jiao Tong University. He is an executive director of Offshore Wind Integration and Consumption Sub-committee of IEEE PES Wind/PV Technical Committee (China), member of Artificial Intelligence and Electrical Applications Specialized Committee of China Electrotechnical Society (CES). He is a Senior member of IEEE and CES. His main research interests include wind power generation, dynamic stability of MMC-based HVDC connected wind farms/PV plants, applications of AI in power electronic systems, etc. As project leader, Dr. Lyu has been in charge of several research projects from government and industry. He serves as a TPC member of several IEEE/IET conferences. He has published more than 80 technical papers and holds more than twenty Chinese granted and pending patents.
Abstract: The wideband oscillation phenomena have frequently occurred in practical MMC-HVDC systems with wind farms, where the oscillation frequency range could be from several Hz to several kHz. This has never been seen in the traditional power system. In this talk, the first commercial MMC-HVDC connected offshore wind farm project in China will be taken as example. The mechanisms and key influencing factors of wideband oscillations in MMC-HVDC connected offshore wind farms will be analyzed. The effective wideband oscillation suppression measures will also be discussed.
Special Speaker 2:
Wireless Power Transfer Based on Electromagnetic Metamaterials: Fundamental, Design, Applications and Challenges
China University of Mining and Technology
Dr. Cancan Rong earned his Ph.D. degree in School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, China, in 2021. He joined the School of Electrical and Power Engineering, China University of Mining and Technology, China, in 2021, where he is currently a lecturer of electric engineering. His research interests are in the areas of wireless power transfer, advanced electrical materials and power converter.
He has published more than 30 selected conference and journal papers. He is the vice-chairman of the 1st China International Youth Conference on Electric Engineering (CIYCEE 2020). He is also invited as the Guest Editor of the Special Issue on “Metamaterials for Wireless Power Transfer” (Materials IF:3.623) in 2021.
Abstract: Wireless Power Transfer (WPT) technology has attracted a great number of attentions due to its convenience, reliability, and safety. This promising technology has broad application prospects, such as consumer electronics, biomedical implants, and electric vehicles (EVs). However, although the WPT technology has numerous advantages, the transfer efficiency in WPT systems decreases rapidly as the distance increases, and large electromagnetic field (EMF) noise is inevitably generated in WPT charging systems and potentially harmful to electronic components, even to human health. The interesting breakthrough in the electromagnetic metamaterials has opened up a creative and innovative paradigm for refocusing propagating waves and amplifying evanescent waves as a ‘perfect lens’. The abilities of metamaterials can be fully applied to WPT system for efficiency enhancement. Later advances in this cross domain further show that the metamaterials with different fabrications can shield the EMF around WPT system as well. The application of the metamaterial in WPT systems has received a great deal of attention in improving the transfer efficiency and reducing the leakage of EMF in recent years.
Special Speaker 3:
Frequency-interactive Control Strategies for Converter-dominated Power Systems
Nanjing Institute of Technology
Liansong Xiong (S’12–M’16–SM’21) was born in Guangyuan, Sichuan, China, in 1986. He received the B.S., M.S., and Ph.D. degrees in electrical engineering from Xi’an Jiaotong University (XJTU), Xi’an, China, in 2009, 2012, and 2016, respectively. Since 2014, he has been a part-time Faculty Member with the School of E-learning, XJTU. In 2016, he joined the Nanjing Institute of Technology (NJIT), Nanjing, China, introduced in High-Level Academic Talent Plan. From 2017 to 2019, he was a Research Associate with the Department of Electrical Engineering, Hong Kong Polytechnic University, Hong Kong. He is currently Deputy Director of the School of Automation, and Director of the Power Electronics Institute, NJIT. His current research interests include renewable energy generation and power system stability. He has obtained 14 research contracts/grants as principal investigator. He is the first author of 15 articles indexed by SCI and more than 20 articles indexed by EI. His publications have been cited over 1200 times, and he has an H-index of 19. He is a recipient of the ICPES Young Scientist Award, the 1st Prize of CPSS Scientific and Technological Progress Award, the 2nd Prize of Shaanxi Natural Science Excellent Paper Award, and the Excellent Doctoral Dissertation of XJTU and Shaanxi Province. He received the Excellent Paper Award 8 times in national/international academic conferences and the National Scholarship for Graduate Students in three consecutive years. He was honored with the XJTU Outstanding Graduates. He is a Senior Member of the IEEE and the CES. He is also a standing Member of the CPSS Youth Working Committee, and a Member of Journal Editorial Board of the Frontiers in Energy Research. He has served as the Program Co-Chair of the AEEES 2021, and the Technical Program Committee Member of IEEE WiPDA-Asia 2018.
Abstract: The renewable energies-dominated power generation revolution and the terminal electrification-dominated energy consumption revolution have been promoting the modern power system marked by a high penetration of various converters for power generation, transmission, distribution, and consumption. At the same time, with the gradual change of leading equipment and the associated evolution of power system dynamic characteristics, the safe and stable operation of converter-dominated power systems is facing major challenges, especially the most urgent frequency stability issues. In recent years, several power blackouts caused by frequency events have occurred in many countries. Therefore, there is an urgent need to pay more attention to frequency stability of the modern power system, and especially to the power converters with frequency-interactive stability.
In this lecture, we will review typical cases of grid frequency events all over the world, summarize technical requirements and development trends of grid codes, and introduce key technologies of frequency-interactive converters actively supporting grid frequency stability by using basic concepts, principles, and methods adopted in power system and power electronics communities. The main contents include: Review of the historical development of power system frequency stability issues, classification of typical frequency-interactive control strategies for converters supporting system frequency stability, comparison of existing technical solutions from the perspectives of technical performance and economic cost, especially introduction of the frequency trajectory planning based converter control strategy that can take into account regulatory requirements of grid code and economic benefits of power producers simultaneously, and finally, summary of ten key technologies remain to be resolved for frequency-interactive converters actively supporting the grid frequency stability.
Special Speaker 4:
Component physical property-based modeling, design, and analysis for the bridgeless AC-DC topologies
Southwest Jiaotong University
Zhengge Chen (S’17–M’21), received the B. S. and M. S. degrees in electrical engineering in 2013 and 2016, respectively, from Southwest Jiaotong University (SWJTU), Chengdu, China. He received the Ph. D. in Energy Technology, from Aalborg University, Aalborg, Denmark, in 2021. Prior to that, He was an Assistant Engineer in Huawei Technologies Co., Ltd, Shenzhen, China，and a Research Assistant at The Hongkong Polytechnic University (PolyU), Hongkong, China. He is currently an Assistant Professor with the Power Conversion and Control Lab, School of Electrical Engineering, Southwest Jiaotong University. His current research interests include AC-DC circuit structure, digital control, magnetic integration, converter reliability analysis.
Abstract: In our modern society, AC-DC converters with the power factor correction (PFC) function are widely used. They are named PFC converters. Since the 1990s, PFC converters have been focused on performance improvements in the aspects of efficiency, input current harmonics, power density, cost, etc. This speech mainly focuses on the question that how to achieve a PFC converter with high efficiency, low volume, and low cost, simultaneously. Our solutions to answer this question includes three steps. The first step is to find the bridgeless topology candidates by the bridgeless topology derivation method. Secondly, the component physical property-based modeling and design procedure are conducted to show us which topology candidate to use in one specific application. Thirdly, the control and analysis aspects are concentrated on the selected topology candidate to ensure that it can be qualified for the targeted application. In our case, the 5G wireless network is the main focused application.
Special Speaker 5:
Frequency-Domain Stability of Electronic Power Systems
KTH Royal Institute of Technology
Yicheng Liao received the B.S. and M.S. degrees in Electrical Engineering from Southwest Jiaotong University, Chengdu, China, in 2015 and 2018, respectively, and the Ph.D. degree in Energy Technology from Aalborg University, Aalborg, Denmark, in 2021. She is currently a Postdoc with the School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, Stockholm, Sweden. Her research interests include the modeling, stability analysis, and control of power electronics-based power systems. She has contributed over 13 journal publications, 10 conference publications, and 1 book chapter.
Abstract: Modern power systems equipped with large amount of power electronic converters may suffer from small-signal instability due to the control interactions. The interoperability among different converter systems become even more challenging because of the confidentiality of converter control. This speech will introduce the frequency-domain stability analysis approach for electronic power systems based on impedance models. First, a unified impedance modeling framework for converter systems is introduced. Next, how to utilize the impedance models for the local-level and system-level stability analysis is presented, which bring different insights. The analyses are elaborated by several case studies in simulations and experiments.
Special Speaker 6:
Impedance modeling techniques for stability analysis of inverter-interfaced renewable energies
Shanghai Jiao Tong University
Dr. Chen Zhang received his Ph.D. from Shanghai Jiao Tong University (SJTU), Shanghai, China in March 2018. He was Postdoc with the Norwegian University of Science and Technology and the Technical University of Denmark respectively in 2018 and 2020. Currently, he is a Tenure-track Associate Professor at the Department of Electrical Engineering, SJTU. His main research interest relates to the time/frequency domain modeling and analysis of grid-tied converters, where the primary focus is to reveal new dynamics and mechanisms associated with the high penetration of power converters. He serves as Associate Editor for IEEE Transactions on Energy Conversion and Reviewers for IEEE PES and PELS journals.
Abstract: The traditional power system is undergoing the paradigm shift towards a more power-electronized system, where substantial inverters have been deployed and utilized as the grid interfaces for renewable energies. However, in such high inverter-penetrated systems, small-signal instability issues typically occurring in the form of oscillations are frequently reported. The impedance-based method is among the most popularly applied approach for such analyses. This presentation will introduce the LTI and LTP framework-based impedance modeling techniques for grid-tied inverters. In which, the impedance transformation techniques that are useful for stability analysis will be introduced, e.g., dq-domain to sequence-domain and MIMO to SISO transformations. A practical method for automating the parametric stability analysis in the LTP framework will be introduced. Technical issues related to the stability analysis of an impedance network will be mentioned and discussed.
Special Speaker 7:
Degradation Modelling of Pantograph-Catenary System Based on Field Test Data in Electrified Railways
Norwegian University of Science and Technology
Yang Song received the PhD degree from Southwest Jiaotong University, China, in 2018. He worked as a Research Fellow with the Institute of Railway Research, University of Huddersfield, the U.K., from October 2018 to September 2019. He is currently a Postdoctoral Researcher with the Department of Structural Engineering, Norwegian University of Science and Technology, Norway. His research interests involve the assessment of pantograph-catenary interactions in electrified railways and the wind-induced vibration of long-span structures in railway transportation. He has been involved in a dozen fundamental research projects and consulting projects sponsored by RSSB, Network Rail, Hitachi Rail and Norwegian Railway Directorate. He is the reviewer for more than 30 international journals, and he also serves as the guest editor of special issues in ‘Sustainability’ and ‘Shock and Vibration’
Abstract: In modern electrified railways, the catenary constructed along the railroad is used to power the electric train through the sliding contact with a pantograph. The current collection quality of the electric train is dominated by the mechanical interaction performance between the contact wire and the pantograph collectors. The current numerical models are primarily used in the design phase to reproduce the ideal response of a perfect system. Nowadays, with the emerging concept of the ‘digital twin’, the numerical models are desirable to describe the degradation in long-term service, which can provide the possibility to reproduce a realistic behaviour and predict the evolvement of performance. To achieve this goal, we performed two field tests on the Gardemobanen line in Norwegian Network to obtain the static and dynamic parameters of a realistic catenary. The modification of the current numerical model using the field test data is discussed. Some comparative results against the inspection data will be introduced.
Special Speaker 8:
Observability analysis of a power system stochastic dynamic model using a derivative-free approach
Zongsheng Zheng (M’20) received the Ph.D. degree in electrical engineering from Southwest Jiaotong University, Chengdu, China, in 2020. During 2018- 2019, he was a Visiting Scholar at the Bradley Department of Electrical and Computer Engineering at Virginia Tech-Northern Virginia Center, Falls Church, VA, USA. He is currently a Research Associate Professor at the College of Electrical Engineering, Sichuan University. His research interests include uncertainty quantification, parameter and state estimation.
Abstract: Serving as a prerequisite to power system dynamic state estimation, the observability analysis of a power system dynamic model has recently attracted the attention of many power engineers. However, because this model is typically nonlinear and large-scale, the analysis of its observability is a challenge to the traditional derivative-based methods. Indeed, the linear-approximation-based approach may provide unreliable results while the nonlinear-technique-based approach inevitably faces extremely complicated derivations. Furthermore, because power systems are intrinsically stochastic, the traditional deterministic approaches may lead to inaccurate observability analyses. Facing these challenges, we propose a novel polynomial-chaos-based derivative-free observability analysis approach that not only is free of any linear approximations, but also accounts for the stochasticity of the dynamic model while bringing a low implementation complexity. Furthermore, this approach enables us to quantify the degree of observability of a stochastic model, what conventional deterministic methods cannot do. The excellent performance of the proposed method has been demonstrated by performing extensive simulations using a synchronous generator model with IEEE-DC1A exciter and the TGOV1 turbine governor.
Special Speaker 9:
Operational reliability enhancement methods for the power converter in IM drives
Keting Hu received the B.S. and Ph.D degree in Electrical Engineering from Southwest Jiaotong University, Chengdu, China, in 2014 and 2020. From 2017 to 2018, he was a guest Ph.D student at Aalborg University, Aalborg, Denmark. In 2021, he became a postdoc with the Maglev Transportation Engineering R&D Center, Tongji University, Shanghai, China. His research interests include the fault diagnosis and fault tolerance of power converters in drive systems.
Abstract: Due to the robust structure, low price and supply maturity, induction machine (IM) drive systems are widely used in industrial applications, e.g., electric aircraft, railways, wind turbines, etc. Accordingly, safety is a crucial problem and the reliability of the IM drive system is in high demand. In this presentation, two techniques that can enhance the operational reliability of the power converters in the IM drives will be presented. Firstly, the “fault diagnosis + fault tolerance” scheme will be introduced, which can ensure continuous operation after the catastrophic failure of the power converter. Then, the “lifetime prediction” scheme that can prevent degradation failure will be discussed.