HVDC and FACTS converters employing SiC power semiconductors. Part 2: SiC-based converter cells

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Project abstract

The project aims at finding solutions for future HVDC and Facts converters using SiC power semiconductor devices. The project consists of two parts, one focusing on the device level research (HV SiC devices and their commutation) and the other part (SiC-based converter cells) on topologies and cell design.

SiC is a wide bandgap material and may be superior to conventional Si semiconductor devices in many aspects. Depending on optimization and device structure, SiC enables higher blocking voltages, faster switching (lower switching losses), and better electric conductivity (reduced conduction losses). SiC has a better thermal conductivity than Si, so higher operation temperatures are possible.

Now that the project is completed, more about its results can be see in the PhD defence video.

Summary of work

In order to transition to renewable energy sources and simultaneously meet the increasing demand for electrical energy, highly flexible and efficient grids are required. High-voltage direct-current (HVDC) transmission and grids are foreseen to be a vital part of the future electricity grid. Voltage source converters (VSCs), interfacing between HVDC and high-voltage alternating current (HVAC) technology, need to comply with grid code, and offer high reliability and cost efficiency. The state-of-the-art VSC topology is the modular multilevel converter (MMC), which offers tailored harmonic performance, modularity, fault handling, redundancy, and low losses.

This project investigates improvements for VSCs enabled by novel silicon carbide (SiC) power semiconductor devices. These devices feature lower losses, higher blocking voltage, and higher maximum operation temperature. However, a co-design of the different hardware levels (i.e., converter, submodule (SM), power device, and semiconductor) is required to unleash their full potential. The thesis features contributions on several of these hardware levels, aiming at improvements regarding defined technical requirements for VSCs.

It has been shown that, on converter level, future ultra-high-voltage (UHV) SiC bipolar devices with blocking voltages of up to 50 kV have the potential for significant reduction of converter complexity, volume, and losses. The increased SM voltage is a challenge for internal fault handling, which can be met by a proposed novel SM feature, the discharge loop.

On SM level, additional improvements are enabled by synergies between power semiconductor device technology and SM topology. A comparative evaluation of a large variety of SM topologies in combination with different SiC power semiconductor device technologies identifies several promising design approaches for future SMs.

An alternative to the state-of-the-art half-bridge and full-bridge SM is the semi-full-bridge, which is investigated intensively. It features lower switch count and lower losses compared to the full-bridge, while offering DC fault handling capability. Another topology, the double-connected double-zero SM, features additional conduction loss reduction in combination with SiC metal-oxide-semiconductor field-effect transistors (MOSFETs), which is enabled by parallel current paths during certain switching states. A SM cluster enhancing this effect is proposed.

Finally, results on the optimization of SiC PiN diodes via different charge carrier lifetime tailoring methods are presented. The target application is a high-voltage high-frequency LCC converter. In the future, such diodes will also be required as anti-parallel diodes for novel UHV bipolar SiC devices, as bootstrap diodes in gate drivers, and as a part of snubber circuits.

Event log

2015. A literature study has been conducted. It covers different converter types (2-level converter, 3-level converter, Modular Multilevel Converter, Alternating Arm Converter, etc.) and a variety of submodule topologies for Modular Multilevel Converters. Additionally, a simulative comparison (including losses, functionality, etc.) with data of currently available (and future) power semiconductor devices will be done.

2016. Literature review completed, and project-focus determined. Lab safety equipment for HV experiments built up. Involvement in experimental setup of “Soft switching converter cells” (with M. Heuvelmans et al). Planning of a HV double pulse test circuit for max. 15 kV devices. A conference article has been presented in 2016, and two more are submitted or under way for 2017.

2017. UHV SiC semiconductor devices (blocking voltages >10 kV) have been the focus of theoretical investigations. A conference paper on their potential for modular multilevel converters has been presented. One problem associated with such high voltages is the stored energy in these converter submodules. Theoretical work has been done on the discharge loop principle, which was presented in a conference publication. Furthermore, there has been an involvement in research on the semi-full-bridge submodule topology (collaboration with Stefanie Heinig) and experimental blocking voltage tests on 15 kV SiC BJT chips (in collaboration with EKT, Kista).

2018. The focus of the investigations for HVDC applications shifted away from UHV semiconductors to the available SiC semiconductor technologies (SiC MOSFET). Experimental work on SiC MOSFET matrix switches is being planned. Experimental investigations on 10 kV bipolar SiC diodes in soft switching applications have been started. A conference publication presented a submodules cluster with low conduction losses, particularly suitable for implementation with SiC MOSFETs.

2019. Preliminary tests were run on simultaneously parallel and series connected SiC MOSFET modules (500 A ,1,2 kV). A simple driver was designed and the switching performance was measured in a double pulse test circuit. An experimental setup (high-voltage high-frequency LCC converter) was finalized and measurements on 10 kV SiC PiN diodes started.

2020. The final year focused on writing publications and the thesis. Experimental work was completed in May and the thesis was defended in November.

Project reference-group

Frans Dijkhuizen,  ABB
Kalle Ilves,  ABB
Jan Svensson,  ABB
Staffan Norrga,  KTH
Hans-Peter Nee,  KTH

Publications by this researcher

See alternatively the researcher's full DiVA list of publications, with options for sorting.
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Auxiliary Power Supplies for High-Power Converter Submodules : State of the Art and Future Prospects
Stefanie Heinig,   Keijo Jacobs,   Kalle Ilves,   Staffan Norrga,   Hans-Peter Nee.
2022,   IEEE transactions on power electronics, vol. 37(6)

Static and Dynamic Performance of Charge-Carrier Lifetime-Tailored High-Voltage SiC p-i-n Diodes With Capacitively Assisted Switching
Keijo Jacobs,   Mietek Bakowski,   Per Ranstad,   Hans-Peter Nee.
2022,   IEEE transactions on power electronics, vol. 37(10)

Localized Lifetime Control of 10 kV 4H-SiC PiN Diodes by MeV Proton Implantation
Zimo Yuan,   Keijo Jacobs,   M. Bakowski,   P. Ranstad,   A. Schöner,   S. Reshanov,   W. Kaplan,   Hans-Peter Nee,   Anders Hallén.
2022,   13th European Conference on Silicon Carbide and Related Materials, ECSCRM 2021, 24 October 2021 through 28 October 2021

Comparative Evaluation of Voltage Source Converters With Silicon Carbide Semiconductor Devices for High-Voltage Direct Current Transmission
Keijo Jacobs,   Stefanie Heinig,   Daniel Johannesson,   Staffan Norrga,   Hans-Peter Nee.
2021,   IEEE transactions on power electronics, vol. 36(8)

Wide-Range Prediction of Ultra-High Voltage SiC IGBT Static Performance Using Calibrated TCAD Model
Daniel Johannesson,   Keijo Jacobs,   Staffan Norrga,   Anders Hallén,   Muhammad Nawaz,   Hans-Peter Nee.
2020,   18th International Conference on Silicon Carbide and Related Materials 2019 (ICSCRM 2019)

Silicon-Carbide-Based High-Voltage Submodules for HVDC Voltage-Source Converters
Keijo Jacobs.
2020,   Thesis (PhD), KTH Royal Institute of Technology, TRITA-EECS-AVL 2020:56

Auxiliary Power Supplies for High-Power Converter Submodules: State-of-the-Art and Future Prospects
Stefanie Heinig,   Keijo Jacobs,   Kalle Ilves,   Staffan Norrga,   Hans-Peter Nee.

Single-Fiber Combined Optical Power and Data Transmission for High-Voltage Applications
Stefanie Heinig,   Keijo Jacobs,   Staffan Norrga,   Hans-Peter Nee.
2020,   The 46th Annual Conference of the IEEE Industrial Electronics Society, IECON 2020, Singapore, October 18-21, 2020

Implications of Capacitor Voltage Imbalance on the Operation of the Semi-Full-Bridge Submodule
Stefanie Heinig,   Keijo Jacobs,   Kalle Ilves,   Luca Bessegato,   Panagiotis Bakas,   Staffan Norrga,   Hans-Peter Nee.
2019,   IEEE transactions on power electronics, vol. 34(10)

Low Loss Submodule Cluster for Modular Multilevel Converters Suitable for Implementation with SiC MOSFETs
Keijo Jacobs,   Stefanie Heinig,   Baris Ciftci,   Staffan Norrga,   Hans-Peter Nee.
2019,   IEEE Energy Conversion Congress and Exposition - IEEE-ECCE 2019, Baltimore, MD, Sept. 29 – Oct. 3, 2019

Reduction of Switching Frequency for the Semi-Full-Bridge Submodule Using Alternative Bypass States
Stefanie Heinig,   Keijo Jacobs,   Kalle Ilves,   Staffan Norrga,   Hans-Peter Nee.
2018,   20th European Conference on Power Electronics and Applications (EPE ECCE Europe), SEP 17-21, 2018, Riga, LATVIA

Dissipation Loop for Shoot-Through Faults in HVDC Converter Cells
Keijo Jacobs,   Hans-Peter Nee,   Staffan Norrga.
2018,   8th International Power Electronics Conference (IPEC-Niigata ECCE Asia) Location: Niigata, JAPAN

15 kV-Class Implantation-Free 4H-SiC BJTs With Record High Current Gain
Arash Salemi,   Hossein Elahipanah,   Keijo Jacobs,   Carl-Mikael Zetterling,   Mikael Östling.
2018,   IEEE Electron Device Letters, vol. 39(1)

Implications of Capacitor Voltage Imbalance on the Operation of the Semi-Full-Bridge Submodule
Stefanie Heinig,   Keijo Jacobs,   Kalle Ilves,   Staffan Norrga,   Hans-Peter Nee.
2017,   2017 19th European Conference on Power Electronics and Applications (EPE'17 ECCE Europe), SEP 11-14, 2017

MMC Converter Cells Employing Ultrahigh-Voltage SiC Bipolar Power Semiconductors
Keijo Jacobs,   Daniel Johannesson,   Staffan Norrga,   Hans-Peter Nee.
2017,   19th European Conference on Power Electronics and Applications (EPE ECCE Europe), SEP 11-14, 2017, Warsaw, Poland

Potential of Ultra-High Voltage Silicon Carbide Semiconductor Devices
Daniel Johannesson,   Muhammad Nawaz,   Keijo Jacobs,   Staffan Norrga,   Hans-Peter Nee.
2016,   4th IEEE Workshop on Wide Bandgap Power Devices and Applications (WiPDA), NOV 07-09, 2016, Fayetteville, AR

Investigation of the Surge Current Capability of the Body Diode of SiC MOSFETs for HVDC Applications
Diane-Perle Sadik,   Stefanie Heinig,   Keijo Jacobs,   Daniel Johannesson,   Jan-Kwon Lim,   Muhammad Nawaz,   Frans Dijkhuizen,   Mietek Bakowski,   Staffan Norrga,   Hans-Peter Nee.
2016,   18th European Conference on Power Electronics and Applications (EPE), SEP 05-09, 2016, GERMANY

Modelling of semiconductor losses of the Modular Multilevel Converter in EMTP
Keijo Jacobs,   Hani Saad,   Sebastien Dennetière.
2016,   17th IEEE Workshop on Control and Modeling for Power Electronics, COMPEL 2016, 27 June 2016 through 30 June 2016

Publication list last updated from DiVA on 2024-01-10 15:20.

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