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Silicon Carbide n-IGBTs: Structure Optimization for Ruggedness Enhancement (2024)
Journal Article
Almpanis, I., Antoniou, M., Evans, P., Empringham, L., Gammon, P., Undrea, F., …Lophitis, N. (2024). Silicon Carbide n-IGBTs: Structure Optimization for Ruggedness Enhancement. IEEE Transactions on Industry Applications, https://doi.org/10.1109/tia.2024.3354870

In recent years, silicon carbide (SiC) based devices are increasingly replacing their silicon counterparts in power conversion applications due to their performance superiority. SiC insulated-gate bipolar transistors are particularly interesting as t... Read More about Silicon Carbide n-IGBTs: Structure Optimization for Ruggedness Enhancement.

10kV+ Rated SiC n-IGBTs: Novel Collector-Side Design Approach Breaking the Trade-Off between dV/dt and Device Efficiency (2023)
Journal Article
Almpanis, I., Evans, P., Antoniou, M., Gammon, P., Empringham, L., Undrea, F., …Lophitis, N. (2023). 10kV+ Rated SiC n-IGBTs: Novel Collector-Side Design Approach Breaking the Trade-Off between dV/dt and Device Efficiency. Key Engineering Materials, 946, 125-133. https://doi.org/10.4028/p-21h5lt

10kV+ rated 4H- Silicon Carbide (SiC) Insulated Gate Bipolar Transistors (IGBTs) have the potential to become the devices of choice in future Medium Voltage (MV) and High Voltage (HV) power converters. However, one significant performance concern of... Read More about 10kV+ Rated SiC n-IGBTs: Novel Collector-Side Design Approach Breaking the Trade-Off between dV/dt and Device Efficiency.

Influence of Emitter Side Design on the Unintentional Turn-on of 10kV+ SiC n-IGBTs (2022)
Conference Proceeding
Almpanis, I., Antoniou, M., Evans, P., Empringham, L., Gammon, P., Udrea, F., …Lophitis, N. (2022). Influence of Emitter Side Design on the Unintentional Turn-on of 10kV+ SiC n-IGBTs. In 2022 IEEE Energy Conversion Congress and Exposition (ECCE). https://doi.org/10.1109/ecce50734.2022.9947492

Silicon Carbide (SiC) N-channel Insulated Gate Bipolar Transistors (n-IGBTs) rated higher than 10kV can improve Medium Voltage and High Voltage power electronics due to the favourable combination of SiC material with the nIGBT device structure. This... Read More about Influence of Emitter Side Design on the Unintentional Turn-on of 10kV+ SiC n-IGBTs.

Short-Circuit Performance Investigation of 10kV+ Rated SiC n-IGBT (2022)
Conference Proceeding
Almpanis, I., Gammon, P., Mawby, P., Evans, P., Empringham, L., Lophitis, N., …Udrea, F. (2022). Short-Circuit Performance Investigation of 10kV+ Rated SiC n-IGBT. In IEEE Workshop on Wide Bandgap Power Devices and Applications in Europe (WiPDA-Europe). https://doi.org/10.1109/WiPDAEurope55971.2022.9936475

This paper presents a comprehensive short-circuit robustness investigation of 4H- Silicon Carbide (SiC) n-type Insulated Gate Bipolar Transistors (nIGBTs) for Medium-Voltage and High- Voltage applications. Numerical electrothermal TCAD simulations ev... Read More about Short-Circuit Performance Investigation of 10kV+ Rated SiC n-IGBT.

Cooling System Sizing using LPTN Analysis and Multiphysics Modelling for an Axial Flux Machine and Integrated Drive (2022)
Conference Proceeding
Jeffrey, A. J., Connor, P. H., Vakil, G., Evans, P., Wheeler, P., & Hart, S. (2022). Cooling System Sizing using LPTN Analysis and Multiphysics Modelling for an Axial Flux Machine and Integrated Drive. . https://doi.org/10.1109/icem51905.2022.9910820

In this paper a Lumped Parameter Thermal Network (LPTN) is proposed for a Yokeless and Segmented Armature (YASA) axial flux permanent magnet (AFPM) machine. A simulation model is used to examine the machine in isolation, with an Integrated Motor Driv... Read More about Cooling System Sizing using LPTN Analysis and Multiphysics Modelling for an Axial Flux Machine and Integrated Drive.

Reduce-Order Analysis and Circuit-Level Cost Function for the Numerical Optimization of Power Electronics Modules (2021)
Conference Proceeding
Cairnie, M., DiMarino, C., Evans, P., & Lophitis, N. (2021). Reduce-Order Analysis and Circuit-Level Cost Function for the Numerical Optimization of Power Electronics Modules. In 2021 IEEE 22nd Workshop on Control and Modelling of Power Electronics (COMPEL). https://doi.org/10.1109/compel52922.2021.9645944

Energy innovation trends such as sustainable grids, and the electrification of the consumer transportation market are accelerating the adoption of medium-voltage (MV) silicon-carbide (SiC) technology. The fast switching times and higher operating tem... Read More about Reduce-Order Analysis and Circuit-Level Cost Function for the Numerical Optimization of Power Electronics Modules.

A GaN-HEMT Compact Model Including Dynamic RDSon Effect for Power Electronics Converters (2021)
Journal Article
Li, K., Evans, P. L., Johnson, C. M., Videt, A., & Idir, N. (2021). A GaN-HEMT Compact Model Including Dynamic RDSon Effect for Power Electronics Converters. Energies, 14(8), Article 2092. https://doi.org/10.3390/en14082092

In order to model GaN-HEMT switching transients and determine power losses, a compact model including dynamic RDSon effect is proposed herein. The model includes mathematical equations to represent device static and capacitance-voltage characteristic... Read More about A GaN-HEMT Compact Model Including Dynamic RDSon Effect for Power Electronics Converters.

Real-Time Thermal Imaging Using Augmented Reality and Accelerated 3D Models (2020)
Conference Proceeding
Jalal, B., Greedy, S., & Evans, P. (2020). Real-Time Thermal Imaging Using Augmented Reality and Accelerated 3D Models. . https://doi.org/10.1109/compel49091.2020.9265658

We present an innovative method to allow real-time visualisation of temperature fields on power electronic circuits using augmented reality. A real-time time-domain simulation incorporating the Block Arnoldi model order reduction techniques is implem... Read More about Real-Time Thermal Imaging Using Augmented Reality and Accelerated 3D Models.

Multi?frequency averaging (MFA) model of a generic electric vehicle powertrain suitable under variable frequency of averaging developed for remote operability (2020)
Journal Article
Sen, S., Evans, P. L., & Johnson, C. M. (2020). Multi?frequency averaging (MFA) model of a generic electric vehicle powertrain suitable under variable frequency of averaging developed for remote operability. IET Electrical Systems in Transportation, 10(3), 268-274. https://doi.org/10.1049/iet-est.2019.0043

© The Institution of Engineering and Technology 2020. Geographically distributed hardware-in-the-loop (HIL) testing has the potential to allow hybrid vehicle powertrain components (battery, motor drive, and engine) to be developed at geographically r... Read More about Multi?frequency averaging (MFA) model of a generic electric vehicle powertrain suitable under variable frequency of averaging developed for remote operability.

Accurate Measurement of Dynamic ON-state Resistance of GaN Devices under Reverse and Forward Conduction in High Frequency Power Converter (2020)
Journal Article
Li, K., Videt, A., Idir, N., Evans, P., & Johnson, M. (2020). Accurate Measurement of Dynamic ON-state Resistance of GaN Devices under Reverse and Forward Conduction in High Frequency Power Converter. IEEE Transactions on Power Electronics, 35(9), 9652-9662. https://doi.org/10.1109/TPEL.2019.2961604

Because of trapped charges in GaN transistor structure, device dynamic ON-state resistance RDSon is increased when it is operated in high frequency switched power converters, in which device is possibly operated by zero voltage switching (ZVS) to red... Read More about Accurate Measurement of Dynamic ON-state Resistance of GaN Devices under Reverse and Forward Conduction in High Frequency Power Converter.

Multi-Frequency Averaging (MFA) Model of Electric-Hybrid Powertrain Suitable for Variable Frequency Operation Applied in Geographically-Distributed Power Hardware-in-the-Loop (GD-PHiL) Simulation (2018)
Conference Proceeding
Sen, S., Evans, P. L., & Johnson, C. M. (2018). Multi-Frequency Averaging (MFA) Model of Electric-Hybrid Powertrain Suitable for Variable Frequency Operation Applied in Geographically-Distributed Power Hardware-in-the-Loop (GD-PHiL) Simulation. In Proceedings - 2018 IEEE Vehicle Power and Propulsion Conference (VPPC) (1-6). https://doi.org/10.1109/VPPC.2018.8604967

© 2018 IEEE Project aims to develop capability for OEMs and suppliers to 'virtually-connect' multiple prototype powertrain components (engine, motor-drive etc.) and engage in real-time system simulation, thereby reducing cost by eliminating co-locati... Read More about Multi-Frequency Averaging (MFA) Model of Electric-Hybrid Powertrain Suitable for Variable Frequency Operation Applied in Geographically-Distributed Power Hardware-in-the-Loop (GD-PHiL) Simulation.

Characterisation and modelling of gallium nitride power semiconductor devices dynamic on-state resistance (2017)
Journal Article
Li, K., Evans, P., & Johnson, M. (2018). Characterisation and modelling of gallium nitride power semiconductor devices dynamic on-state resistance. IEEE Transactions on Power Electronics, 33(6), 5262 - 5273. https://doi.org/10.1109/TPEL.2017.2730260

GaN-HEMTs suffer from trapping effects which increases device ON-state resistance (RDS(on)) above its theoretical value. This increase is a function of the applied DC bias when the device is in its OFF state, and the time which the device is biased f... Read More about Characterisation and modelling of gallium nitride power semiconductor devices dynamic on-state resistance.

SiC/GaN power semiconductor devices: a theoretical comparison and experimental evaluation under different switching conditions (2017)
Journal Article
Li, K., Evans, P., & Johnson, M. (in press). SiC/GaN power semiconductor devices: a theoretical comparison and experimental evaluation under different switching conditions. IET Electrical Systems in Transportation, https://doi.org/10.1049/iet-est.2017.0022

The conduction and switching losses of SiC and GaN power transistors are compared in this paper. Voltage rating of commercial GaN power transistors is less than 650V while that of SiC power transistors is less than 1200V. The paper begins with a theo... Read More about SiC/GaN power semiconductor devices: a theoretical comparison and experimental evaluation under different switching conditions.

Using multi time-scale electro-thermal simulation approach to evaluate SiC-MOSFET power C=converter in virtual prototyping design tool (2017)
Conference Proceeding
Li, K., Evans, P., & Johnson, C. M. (in press). Using multi time-scale electro-thermal simulation approach to evaluate SiC-MOSFET power C=converter in virtual prototyping design tool.

Using virtual prototyping (VP) design tool to eval¬uate power converter electro-thermal performance can help designers to validate prototype in a quick way. However, different system time-scale requires efficient electro-thermal simulation techniques... Read More about Using multi time-scale electro-thermal simulation approach to evaluate SiC-MOSFET power C=converter in virtual prototyping design tool.

SiC and GaN power transistors switching energy evaluation in hard and soft switching conditions (2016)
Conference Proceeding
Li, K., Evans, P., & Johnson, C. M. (2016). SiC and GaN power transistors switching energy evaluation in hard and soft switching conditions.

SiC and GaN power transistors switching energy are compared in this paper. In order to compare switching energy Esw of the same power rating device, a theoretical analysis is given to compare SiC device conduction loss and switching losses change whe... Read More about SiC and GaN power transistors switching energy evaluation in hard and soft switching conditions.

SiC/GaN power semiconductor devices theoretical comparison and experimental evaluation (2016)
Conference Proceeding
Li, K., Evans, P., & Johnson, C. M. (2016). SiC/GaN power semiconductor devices theoretical comparison and experimental evaluation.

SiC and GaN power transistors conduction loss and switching losses are compared in this paper. In order to compare performance of the same power rating device, a theoretical analysis is given to compare SiC device conduction loss and switching losses... Read More about SiC/GaN power semiconductor devices theoretical comparison and experimental evaluation.

Developing power semiconductor device model for virtual prototyping of power electronics systems (2016)
Conference Proceeding
Li, K., Evans, P., & Johnson, C. M. (2016). Developing power semiconductor device model for virtual prototyping of power electronics systems.

Virtual prototyping (VP) is very important for power electronics systems design. A virtual prototyping design tool based on different modelling technology and model order reduction is proposed in the paper. In order to combine circuit electromagnetic... Read More about Developing power semiconductor device model for virtual prototyping of power electronics systems.

GaN-HEMT dynamic ON-state resistance characterisation and modelling (2016)
Conference Proceeding
Li, K., Evans, P., & Johnson, C. M. (2016). GaN-HEMT dynamic ON-state resistance characterisation and modelling.

GaN-HEMTs suffer from trapping effects which might increase device ON-state resistance (RDS(on)) values. Thus, dynamic RDS(on) of a commercial GaN-HEMT is characterized at different bias voltages in the paper by a proposed measurement circuit. Based... Read More about GaN-HEMT dynamic ON-state resistance characterisation and modelling.

Damage Evolution in Al Wire Bonds Subjected to a Junction Temperature Fluctuation of 30K (2016)
Journal Article
Agyakwa, P., Yang, L., Arjmand, E., Evans, P., Corfield, M., & Johnson, C. M. (2016). Damage Evolution in Al Wire Bonds Subjected to a Junction Temperature Fluctuation of 30K. Journal of Electronic Materials, 45, 3659-3672. https://doi.org/10.1007/s11664-016-4519-0

© 2016, The Author(s). Ultrasonically bonded heavy Al wires subjected to a small junction temperature fluctuation under power cycling from 40°C to 70°C were investigated using a non-destructive three-dimensional (3-D) x-ray tomography evaluation appr... Read More about Damage Evolution in Al Wire Bonds Subjected to a Junction Temperature Fluctuation of 30K.

Design Tools for Rapid Multidomain Virtual Prototyping of Power Electronic Systems (2015)
Journal Article
Evans, P. L., Castellazzi, A., & Johnson, C. M. (2016). Design Tools for Rapid Multidomain Virtual Prototyping of Power Electronic Systems. IEEE Transactions on Power Electronics, 31(3), 2443-2455. https://doi.org/10.1109/TPEL.2015.2437793

The need for multidisciplinary virtual prototyping in power electronics has been well established, however, design tools capable of facilitating a rapid iterative virtual design process do not exist. A key challenge in developing such tools is identi... Read More about Design Tools for Rapid Multidomain Virtual Prototyping of Power Electronic Systems.