Impact of Gallium Nitride Switching Devices on High-Frequency Power Electronics Converters

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School of Electrical Engineering | Doctoral thesis (article-based) | Defence date: 2021-09-21
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Date

2021

Department

Sähkötekniikan ja automaation laitos
Department of Electrical Engineering and Automation

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Mcode

Degree programme

Language

en

Pages

92 + app. 112

Series

Aalto University publication series DOCTORAL DISSERTATIONS, 121/2021

Abstract

Power converters for photo-voltaic (PV) grid are one of the main applications of Gallium Nitride (GaN) switching devices. These converters in grid-connected applications are also required to supply reactive power. During the flow of reactive power, switching devices have to conduct in reverse direction. However, these GaN HEMTs suffer from high voltage drop during the reverse conduction. It is very critical to accurately model these additional losses to achieve the optimized performance. HERIC inverter from transformer-less solar inverter family is chosen for this work due to its high efficiency performance and low leakage current. Conduction losses for the inverter including reverse conduction losses are modelled for various existing uni-polar PWM schemes. Results showed that for loads with low power factor, reverse conduction losses constitute the majority of the total conduction losses. Based on these results, a modified uni-polar PWM scheme is introduced to reduce these losses and enhance the efficiency of the inverter. Fast switching of these GaN HEMTs have made it possible to reduce the size of magnetic components and increase the overall power density of the system. However, fast switching transitions in the converter, generate higher electro-magnetic-interference (EMI) noise. To reduce the noise emissions of the converter it is essential to reduce the parasitic elements in the converter. These parasitic elements facilitate the propagation of high-frequency noise, which will require bulkier EMI filters to comply with power quality standards. Hence, in this work a high voltage gain converter with multi-phase coupled inductor, for electric vehicle (EV) applications, is considered as a case study. A comprehensive model of the inductor structure, including parasitic capacitances is presented in this thesis. The values of those parasitic capacitances are computed with the aid of computer aided simulations and by performing impedance measurements on inductor prototype. EMI measurements of the converter verify that by optimizing the parasitic elements, noise emissions of the converter can be reduced. GaN devices are also suitable candidates for switching devices in power converters for modernized, more electric aircrafts (MEA). In addition to improving the performance of converters by the application of these switching devices, it is also very critical to review new converter topologies. Two power factor correction (PFC) topologies, Swiss rectifier and Delta rectifier, are considered for this study due to their low number of high-frequency switches. Detailed simulation models of these rectifiers are developed to choose an appropriate topology for their application as front-end rectifier in an isolated AC-DC power supply. After the selection of the rectifier topology, an isolated DC-DC converter is designed and optimized with the aid of an optimization tool. Practical performance of the converter is also enhanced by the application of GaN devices and by minimizing the parasitic elements in the transformer and printed circuit boards (PCBs).

Description

Defense is held on 21.9.2021 12:15 – 15:15 via remote technology, https://aalto.zoom.us/j/62622110601

Supervising professor

Kyyrä, Jorma, Prof., Aalto University, Department of Electrical Engineering and Automation, Finland

Keywords

WBG, MEA, HERIC, EMC, PFC, EMI, GaN, DC/DC, AC/DC, DC/AC

Other note

Parts

  • [Publication 1]: Bilal Ahmad, Wilmar Martinez, Jorma Kyyrä. Performance analysis of a transformer-less solar inverter with modified PWM. In IEEE 6th International Conference on Renewable Energy Research and Applications (ICRERA), San Diego, CA, pp.1024-1029, Nov 2017.
    DOI: 10.1109/ICRERA.2017.8191213 View at publisher
  • [Publication 2]: Bilal Ahmad, Wilmar Martinez, Jorma Kyyrä. Modified Modulation Signals for GaN-E-HEMTs Based HERIC Inverter to Improve Reverse Conduction Performance. In 20th European Conference on Power Electronics and Applications (EPE’18 ECCE Europe), Riga, 10 Pages, Sep 2018.
    Full text in Acris/Aaltodoc: http://urn.fi/URN:NBN:fi:aalto-201812106203
  • [Publication 3]: Bilal Ahmad, Wilmar Martinez, Jorma Kyyrä. Modified PWM Signals to Reduce Reverse Conduction Losses in GaN Based HERIC Inverter. Submitted to IEEE Access, 9 Pages, April, 2021
  • [Publication 4]: Bilal Ahmad, Wilmar Martinez, Jorma Kyyrä. Efficiency Optimisation of an Interleaved High Step-up Converter. The Journal of Engineering, Volume 2019, Issue 17,pp. 4167-4172, IET.
    Full text in Acris/Aaltodoc: http://urn.fi/URN:NBN:fi:aalto-201909035157
    DOI: 10.1049/joe.2018.8040 View at publisher
  • [Publication 5]: Bilal Ahmad, Wilmar Martinez, Jorma Kyyrä. Common Mode Noise Analysis for a High Step-Up Converter with GaN Devices. In IEEE Energy Conversion Congress and Exposition (ECCE), Portland, OR, pp. 1240-1246, Sep 2018.
    Full text in Acris/Aaltodoc: http://urn.fi/URN:NBN:fi:aalto-201901301470
    DOI: 10.1109/ECCE.2018.8557647 View at publisher
  • [Publication 6]: Bilal Ahmad, Prasad Jayathurathnage, Jorma Kyyrä, Wilmar Martinez. FEA based Model for High-Frequency Design Optimization of a Three-Winding Coupled Inductor for HSU Converters. In 21st European Conference on Power Electronics and Applications (EPE ’19 ECCE Europe), Genova, Italy, 10 Pages, Sep 2019.
    DOI: 10.23919/EPE.2019.8915380 View at publisher
  • [Publication 7]: Bilal Ahmad, Prasad Jayathurathnage, Wilmar Martinez, Jorma Kyyrä. Parameter Extraction Technique for Evaluation of Inductive and Capacitive Elements of Three-Winding Coupled Inductor. Submitted to IEEE Journal of Emerging and Selected Topics in Industrial Electronics, 8 Pages, Feb 2021 IEEE
  • [Publication 8]: Bilal Ahmad, Mikko Routimo, Jorma Kyyrä, Wilmar Martinez. EMI Standard Compliance of Three-Phase Buck Type PFC Rectifier For Application in Aircraft. In IECON 2019 - 45th Annual Conference of the IEEE Industrial Electronics Society, Lisbon, Portugal, pp. 6355-6362, Oct 2019.
    DOI: 10.1109/IECON.2019.8927363 View at publisher
  • [Publication 9]: Bilal Ahmad, Juha Mäkelä, Jorma Kyyrä. Power Supply Design Considerations For 400Hz Aircraft Applications. In European Conference on Power Electronics and Applications (EPE’20 ECCE Europe), 10 Pages, Sep 2020.
    Full text in Acris/Aaltodoc: http://urn.fi/URN:NBN:fi:aalto-2020113020513
    DOI: 10.23919/EPE20ECCEEurope43536.2020.9215784 View at publisher
  • [Publication 10]: Aniket Kulkarni, Bilal Ahmad, Jorma Kyyrä. Role of Parasitics in a Dual Active Bridge DC-DC Converter with Gallium Nitride devices. In European Conference on Power Electronics and Applications (EPE’21 ECCE Europe), 10 Pages, Sep 2021

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https://urn.fi/URN:ISBN:978-952-64-0502-5

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[diss] Sähkötekniikan korkeakoulu / ELEC