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Current Location: Home > People > Faculty & Staff > Electric Power & Electronics and Motor System Research Institute > Teacher with Deputy Senior Title > Content

Ji Shiqi

Associate Professor, Department of Electrical Engineering, Tsinghua University

Research Interests

Power electronics in high/medium voltage and high power applications, Wide bandgap power semiconductors applications, Power electronics in distribution grids

West Main Building, 3-325 Department of Electrical Engineering, Tsinghua University Beijing, 100084, P. R. China

chic2020@tsinghua.edu.cn

010-62790248

  • Biography
  • Teaching
  • Research Projects
  • Publications
  • Social Service

Shiqi Ji received the B.E. and Ph.D. degrees in electrical engineering all from Tsinghua University, Beijing, China, in 2010 and 2015, respectively. Since 2015, he joined as a Research Associate with the Center for Ultra-Wide-Area Resilient Electric Energy Transmission Networks (CURENT), the University of Tennessee, Knoxville, TN, USA, and became a Research Assistant Professor in 2019. From 2020, he joined as an Assistant Professor in Department of Electrical Engineering at Tsinghua University, Beijing, China, and became an Associate Professor in 2021. From Jul. 2013 to Nov. 2013, he was a Research Scholar at the Wisconsin Electric Machines and Power Electronics Consortium (WEMPEC), the University of Wisconsin-Madison, Madison, WI, USA.

His main research interests are power electronics for high/medium voltage and high power applications. From 2010 to 2015, his focus was on Silicon-based technology, and some of them have been applied by industry companies. From 2015, he started to focus on novel high voltage SiC-based technology. As key senior personnel, he was involved in several projects (~8 million USD), e.g. SiC based PCS development for asynchronous microgrid, and SiC based CHP PCS and PV inverter supported by DOE, USA. He has led a group to build a 12.4 kVac/250 kW PV inverter prototype using 10 kV SiC MOSFETs through collaboration with Danfoss and Wolfspeed. Their project of SiC based PCS development for asynchronous microgrid was awarded as highest reviewer rating by Power America Program. From 2020, he started to work on MW-scale medium-voltage multi-port power electronic transformer. As the group leader, they have developed the prototype and demonstrated to support on-site power sources and loads. At Tsinghua University, he has led or participated in more than 5 projects, totaling more than RMB¥30M, with personal share more than ¥5M per year. He has authored more than 70 technical papers, including more than 20 peer-reviewed international journal papers. He hold 5 Chinese patents and 1 US patent.

He served in several professional institutes. He was an IEEE senior member, and also a member of Power Electronics Society and Industry Applications Society. He served in International Technology Roadmap for Wide Bandgap Semiconductors (ITRW) for high voltage SiC power semiconductor related standards. He was guest editors and associated editors for several internal journals. He served for some IEEE international conferences as committee members and session chairs including IEEE Wipda Asia, etc. He was also a reviewer of many IEEE journals in this area including TPEL, TIE, etc., and reviewed more than 50 papers.

Educational Background

2010-2015, Ph.D,Electrical Engineering, Tsinghua University, China

2006-2010, Bachelor of Eng., Electrical Engineering, Tsinghua University, China

Work Experience

Dec.2021-present, Associate Professor,Department of Electrical Engineering, Tsinghua University, Beijing, China

Dec.2020-Dec.2021, Assistant Professor,Department of Electrical Engineering, Tsinghua University, Beijing, China

Apr.2019–Feb.2020, Research Assistant Professor, Electrical Engineering & Computer Science, the University of Tennessee, Knoxville, TN, USA

Sep.2015–Apr.2019, Research Associate, Electrical Engineering & Computer Science, the University of Tennessee, Knoxville, TN, USA

Jul.2013–Nov.2013,Research Scholar,Electrical & Computer Engineering, the University of Wisconsin-Madison, Madison, WI, USA

Honors and Awards

Gold with Congratulations of the Jury, International Exhibition of Inventions of Geneva, 2021

IPEMC Best Paper Award, 2020

Highest Reviewer Rating Project Award, Power America Program, 2019

IEEE APEC Outstanding Presentation, 2018

Excellent Ph.D Dissertation Award, Tsinghua University, 2015

Chinese National Scholarship, China, 2014

ICEMS2011Best Paper Award, 2011

Cai Xuansan Scholarship, Outstanding Student Award, Delta Electric, 2010


Power Electronics and Power Semiconductors (Undergraduates, 32 hrs)

2023-2026, Decoupling control and power oscillation suppression for multi-port power electronic transformers, National Natural Science Foundation of China

2021-2022, MW-scale Multi-port Energy Router, Inovance Technology Co. Ltd, China

2021-2022, IGBT module reliability estimation, Shanghai Mitsubishi Elevator Company, China

2021-2022, 75 kW multi-function three-port power electronic transformer, Shandong Electric Power Research Institute, China

2020-2021, MW-scale Multi-function Multi-port Power Electronic Transformer, National Key R&D Program of China, China

2020-2023,SiC Based Modular Transformer-less MW-Scale Power Conditioning System and Control for Flexible Manufacturing Plants,Department of Energy, USA

2018-2021,SiC based modular transformer-less MW-scale power conditioning system and control for flexible CHP system,Department of Energy, USA

2017-2020,Multi-functional high-efficiency high-density medium voltage SiC based asynchronous microgrid power conditioning system module,Power America, USA

2014-2017, Agile direct grid connection medium voltage 4.7-12.47 kV power converter for PV applications utilizing advanced WBG devices,Department of Energy, USA

2016,Benchmark of Benefits of High Voltage SiC in Medium Voltage Power Distribution Grids,Oak Ridge National Laboratory, USA

2016-2017, Topology Evaluation of Aircraft Electric Power Distribution System, Safran Company, France


(1)Selected International Journal Papers Since 2010

1)H. Li, Z. Gao, S. Ji, Y. Ma, F. Wang, “An inrush current limiting method for grid-connected converters considering grid voltage disturbances,” IEEE Journal of Emerging and Selected Topics in Power Electronics, accepted.

2)X. Huang, S. Ji, C. Nie, D. Li, M. Lin, L. Tolbert, F. Wang, W. Giewont, “Comprehensive analysis and improvement methods of noise immunity of desat protection for high voltage SiC MOSFETs with high dv/dt,” IEEE Open Journal of Power Electronics, vol. 3, pp. 36-50, Dec. 2021.

3)B. Shi,S. Ji, Z. Zhao, Z. Yu, “Discrete-State Event-Driven Numerical Prototyping of Megawatt Solid-State Transformers and AC/DC Hybrid Microgrids,” IEEE Access, vol. 9, pp. 108329-108339, Jul. 2021.

4)S. Ji, X. Huang, J. Palmer, F. Wang, L. Tolbert, “Modular multilevel converter (MMC) modeling considering submodule voltage sensor noise,” IEEE Trans. Power Electron., vol. 36, no. 2, pp. 1215-1219, Feb. 2021.

5)S. Ji, L. Zhang, X. Huang, J. Palmer, F. Wang, L. Tolbert, “A novel voltage balancing control with dv/dt reduction for 10-kV SiC MOSFET-based medium voltage modular multilevel converter,” IEEE Trans. Power Electron., vol.35, no. 11, pp. 12533-12543, Nov. 2020.

6)L. Zhang,S. Ji, S. Gu, X. Huang, J. Palmer, W. Giewont, F. Wang, L. Tolbert, “Design considerations for high-voltage-insulated gate drive power supply for 10-kV SiC MOSFET applied in medium-voltage converter,” IEEE Trans.Ind. Electron., vol. 68, no. 7, pp. 5712-5724, Jul. 2021.

7)P. Yao, X. Jiang, P. Xue,S. Ji, F. Wang, “Flux balancing control of ungapped nanocrystalline core-based transformer in dual active bridge converters,” IEEE Trans. Power Electron., vol.35, no. 11, pp. 11463-11474, Nov. 2020.

8)S. Ji, F. Wang, L. Tolbert, T. Lu, Z. Zhao, H. Yu, “An FPGA based voltage balancing control for multi HV-IGBTs in series connection,” IEEE Trans. on Ind. Appl., vol. 54, no. 5, pp. 4640-4649, Sep. 2018.

9)S. Ji, M. Laitinen, X. Huang, J. Sun, W. Giewont, F. Wang, L. Tolbert, “Short circuit characterization and protection of 10 kV SiC MOSFET,” IEEE Trans. Power Electron., vol. 34, no. 2, pp. 1755-1764, Feb. 2019.

10)B. Shi, Z. Zhao, K. Li, G. Feng,S. Ji, J. Zhou, “Design methodology for optimal phase-shift modulation of non-inverting buck-boost converter,” Journal of Power Electronics., vol. 19, no. 5, pp. 1108-1121, Sep. 2019.

11)S. Ji, S. Zheng, F. Wang, L. M. Tolbert, “Temperature-dependent characterization, modeling and switching speed limitation analysis of third generation 10 kV SiC MOSFET,” IEEE Trans. Power Electron., vol.33, no.5, pp.4317-4327,May. 2018.

12)S. Ji, T. Lu, Z. Zhao, H. Yu, L. Yuan, “Series-connected HV-IGBTs using active voltage balancing control with status feedback circuit,” IEEE Trans. Power Electron., vol. 30, no. 8, pp. 4165-4174, Aug. 2015.

13)S. Ji, T. Lu, Z. Zhao, H. Yu, L. Yuan, S. Yang, C. Secrest, “Physical model analysis during transient for series connected HVIGBTs,” IEEE Trans. Power Electron., vol. 29, no. 11, pp. 5727-5737, Nov. 2014.

14)T. Lu, Z. Zhao, H. Yu,S. Ji, L. Yuan, F. He. “Parameter design of three-level converter based on series connected HV-IGBTs,” IEEE Trans. on Ind. Appl., vol. 50, no. 6, pp. 3943-3954, Nov. 2014.

15)T. Lu, Z. Zhao,S. Ji, H. Yu, L. Yuan. “Active clamping circuit with status feedback for series-connected HV-IGBTs,” IEEE Trans. on Ind. Appl., vol. 50, no. 5, pp. 3579-3590, Sep. 2014.

16)S. Ji, Z. Zhao, T. Lu, L. Yuan, H. Yu. “HVIGBT physical model analysis during transient,” IEEE Trans. Power Electron., vol. 28, no. 5, pp. 2616-2624, May. 2013.

(2)Selected Conference Papers Since 2010

1)D. Li, X. Huang,S. Ji, C. Nie, F. Wang, L. Tolbert, “Controller design and implementation of a medium voltage (13.8 kV) modular multi-level converter for asynchronous microgrids,” IEEE Energy Conversion Congress and Exposition (ECCE), 2020,Detroit, MI.

2)X. Huang,S. Ji, D. LI, C. Nie, L. Tolbert, F. Wang, W. Giewont, “Analysis and gate driver design considerations of 10 kV SiC MOSFETs under flashover fault due to insulation failure,” IEEE Energy Conversion Congress and Exposition (ECCE), 2020,Detroit, MI.

3)X. Huang,S. Ji, D. Li, C. Nie, W. Giewont, L. Tolbert, F. Wang, “A test scheme for the comprehensive qualification of MMC submodule based on 10 kV SiC MOSFETs under high dv/dt,” European Conference on Power Electronics and Applications (EPE), 2020, Lyon, France.

4)S. Ji, J. Palmer, X. Huang, D. Li, W. Giewont, L. Tolbert, F. Wang, “Impact of submodule voltage sensor noise in 10 kV SiC MOSFET modular multilevel converters (MMCs) under high dv/dt environment,” IEEE Applied Power Electronics Conference and Exposition (APEC), 2020, New Orleans, LA, pp. 1089-1093.

5)D. Li,S. Ji, X. Huang, J. Palmer, F. Wang, L. Tolbert, “Controller development of an asynchronous microgrid power conditioning system (PCS) converter considering grid requirements,” IEEE Applied Power Electronics Conference and Exposition (APEC), 2020, New Orleans, LA, pp. 616-621.

6)J. Palmer,S. Ji, X. Huang, L. Zhang, W. Giewont, F. Wang, L. Tolbert, “Improving voltage sensor noise immunity in a high voltage and high dv/dt environment,” IEEE Applied Power Electronics Conference and Exposition (APEC), 2020, New Orleans, LA, pp. 107-113.

7)X. Huang,S. Ji, J. Palmer, L. Zhang, D. Li, F. Wang, L. Tolbert, W. Giewont, “A robust 10 kV SiC MOSFET gate driver with fast overcurrent protection demonstrated in a MMC submodule,” IEEE Applied Power Electronics Conference and Exposition (APEC), 2020, New Orleans, LA, pp. 1813-1820.

8)S. Ji, X. Huang, J. Palmer, L. Zhang, W. Giewont, F. Wang, L. Tolbert, “Medium Voltage (13.8 kV) Transformer-lessGrid-Connected DC/AC ConverterDesignand Demonstration Using 10 kV SiC MOSFET with High Frequency,” IEEE Energy Conversion Congress and Exposition (ECCE), 2019,Baltimore, MD, pp. 1953-1959.

9)J. Palmer,S. Ji, X. Huang, L. Zhang, F. Wang, W. Giewont, L. Tolbert, “Testing andvalidation of 10 kV SiC MOSFET based 35 kVA MMC phase-leg for medium voltage (13.8 kV) grid,” IEEE Energy Conversion Congress and Exposition (ECCE), 2019, Baltimore, MD, pp. 2001-2006.

10)X. Huang, J. Palmer,S. Ji, L. Zhang, F. Wang, L. Tolbert, W. Giewont, “Design and testing of a modular multilevel converter submodule based on 10 kV SiC MOSFETs,” IEEE Energy Conversion Congress and Exposition (ECCE), 2019, Baltimore, MD, pp. 1926-1933.

11)L. Zhang,S. Ji, X. Huang, J. Palmer, W. Giewont, F. Wang, L. Tolbert, “Multiple-step commutation scheme for avoiding high dv/dt in modular multilevel converter with 10 kV SiC MOSFET,” IEEE Energy Conversion Congress and Exposition (ECCE), 2019, Baltimore, MD, pp. 1968-1973.

12)L. Zhang,S. Ji, S. Gu, X. Huang, J. Palmer, W. Giewont, F. Wang, L. Tolbert, “Designconsiderations ofhigh-voltage-insulationgatedriverpowersupply for 10 kV SiCMOSFET inmedium-voltageapplication,” in IEEE Applied Power Electronics Conference and Exposition (APEC), 2019, Anaheim, CA, pp. 425-430.

13)X. Huang,S. Ji, J. Palmer, L. Zhang, L. Tolbert, F. Wang, “Parasitic capacitor’s impact on switching performance in a 10 kV SiC MOSFET based converter,” IEEE Workshop on Wide Bandgap Power Devices and Applications (WiPDA), 2018, Atlanta, GA, pp. 311-318.

14)X. Huang,S. Ji, J. Sun, S. Zheng, F. Wang, L. Tolbert, M. Laitinen, W. Giewont, “Impact of Body Diode and Anti-parallel J B S Diode on Switching Performance of 3rd Generation 10 kV SiC MOSFET,” IEEE Energy Conversion Congress and Exposition (ECCE), 2018, Portland, OR, pp. 1887-1894.

15)S. Ji, M. Laitinen, X. Huang, J. Sun, W. Giewont, L. Tolbert, F. Wang, “Short circuit characterization of 3rd generation 10 kV SiC MOSFET,” in IEEE Applied Power Electronics Conference and Exposition (APEC), San Antonio, TX, 2018.

16)S. Ji, X. Shi, Z. Zhang, W. Cao, F. Wang, “Benefits of high voltage SiC applications in medium voltage power distribution grids,” in International Conference on Silicon Carbide and Related Materials (ICSCRM), Washington, D.C., 2017.

(1) Professional Society Membership

IEEE Senior Member

Member of the Power Electronics Society

Member of the Industry Applications Society

Member of International Technology Roadmap for Wide Bandgap Semiconductors (ITRW)

Member of China Education Association of Machinery Industry


(2) Editorship in International Journals

Guest Editor,CPSS Transactions on Power Electronics and Applications

Associate Editor,Engineering Reports


(3) Services on International Conference

TPC member and session chair of IEEE ECCE-Asia 2020, Nanjing, China

TPC member and session chair of IEEE Wipda-Asia 2021, Wuhan, China