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Implementation of a hybrid AC-AC direct power converter with unity voltage transfer (2008)
Journal Article
Wijekoon, T., Klumpner, C., Zanchetta, P., & Wheeler, P. (2008). Implementation of a hybrid AC-AC direct power converter with unity voltage transfer. IEEE Transactions on Power Electronics, 23(4), https://doi.org/10.1109/TPEL.2008.924601

This paper presents a novel hybrid direct power converter (HDPC) which overcomes the two main disadvantages of matrix converters: limited voltage transfer ratio and low immunity to grid disturbance. The proposed converter is formed by integrating a r... Read More about Implementation of a hybrid AC-AC direct power converter with unity voltage transfer.

Hybrid matrix converter topologies: an exploration of benefits (2008)
Conference Proceeding
Klumpner, C., & Pitic, C. (2008). Hybrid matrix converter topologies: an exploration of benefits. In 2008 IEEE Power Electronics Specialists Conference. https://doi.org/10.1109/PESC.2008.4591887

Matrix converters are direct AC/AC power converters that can operate with sinusoidal output/input voltage/currents without the need of passive components to store energy, which means that they are grid friendly and have a great weight/volume reductio... Read More about Hybrid matrix converter topologies: an exploration of benefits.

Structural and electrical characterization of AuPtAlTi ohmic contacts to AlGaN/GaN with varying annealing temperature and Al content (2008)
Journal Article
Fay, M. W., Han, Y., Brown, P. D., Harrison, I., Hilton, K., Munday, A., …Martin, T. (2008). Structural and electrical characterization of AuPtAlTi ohmic contacts to AlGaN/GaN with varying annealing temperature and Al content. Journal of Applied Physics, 103(7), https://doi.org/10.1063/1.2890978

The effect of varying annealing temperature and Al layer thickness on the structural and electrical characteristics of AuPtAlTi/AlGaN/GaN ohmic contact structures has been systematically investigated. The relationship between annealing temperature, A... Read More about Structural and electrical characterization of AuPtAlTi ohmic contacts to AlGaN/GaN with varying annealing temperature and Al content.

Correlation of electrical and structural properties of Au contacts to KOH treated n-GaN (2004)
Book Chapter
Moldovan, G., Harrison, I., Roe, M., & Brown, P. D. (2004). Correlation of electrical and structural properties of Au contacts to KOH treated n-GaN. In S. McVitie, & D. McComb (Eds.), Electron microscopy and analysis 2003: proceedings of the Institute of Physics Electron Microscopy and Analysis Group Conference, University of Oxford, 3-5 September 2003. Institute of Physics Publishing

A correlated current-voltage (I-V), electron beam induced conductivity (EBIC) and X-ray photoelectron spectroscopy (XPS) study of Au contacts to KOH treated n-type GaN is presented. A strong degradation of I-V characteristics occurs following the KO... Read More about Correlation of electrical and structural properties of Au contacts to KOH treated n-GaN.

TEM assessment of As-doped GaN epitaxial layers grown on sapphire (2004)
Book Chapter
Fay, M. W., Harrison, I., Larkins, E. C., Novikov, S. V., Foxon, C., & Brown, P. D. (2004). TEM assessment of As-doped GaN epitaxial layers grown on sapphire. In S. McVitie, & D. McComb (Eds.), Electron Microscopy and Analysis 2003: Proceedings of the Institute of Physics Electron Microscopy and Analysis Group Conference, University of Oxford, 3-5 September 2003 (23-26). Institute of Physics Publishing

TEM investigations of As-doped GaN layers grown by plasma-assisted molecular beam epitaxy on sapphire substrates reveal the presence of extensive regions of cubic stacking disorder within the hexagonal GaN matrix. Electron energy loss spectroscopy su... Read More about TEM assessment of As-doped GaN epitaxial layers grown on sapphire.

A new class of hybrid AC/AC direct power converters
Conference Proceeding
Klumpner, C., Wijekoon, T., & Wheeler, P. (in press). A new class of hybrid AC/AC direct power converters. In Fourtieth IAS Annual Meeting. Conference Record of the 2005 Industry Applications Conference, 2005. https://doi.org/10.1109/IAS.2005.1518793

Variable voltage and variable frequency conversion of electrical energy from an AC source to an AC load is done in traditional power converters via a DC-link where an energy storage element (electrolytic capacitors) is situated. Despite its well-know... Read More about A new class of hybrid AC/AC direct power converters.

A hybrid indirect matrix converter immune to unbalanced voltage supply, with reduced switching losses and improved voltage transfer ratio
Conference Proceeding
Klumpner, C. (in press). A hybrid indirect matrix converter immune to unbalanced voltage supply, with reduced switching losses and improved voltage transfer ratio. In Twenty-First Annual IEEE Applied Power Electronics Conference and Exposition, 2006. APEC '06. https://doi.org/10.1109/APEC.2006.1620528

Achieving a compact and efficient design of power electronic converters is not a straightforward procedure: minimizing the size of the filter requires a higher switching frequency that causes additional switching losses that will require a larger hea... Read More about A hybrid indirect matrix converter immune to unbalanced voltage supply, with reduced switching losses and improved voltage transfer ratio.

A new two-stage voltage source inverter with modulated DC-link voltage and reduced switching losses
Conference Proceeding
Klumpner, C. (in press). A new two-stage voltage source inverter with modulated DC-link voltage and reduced switching losses. In IECON 2006 - 32nd Annual Conference on IEEE Industrial Electronics. https://doi.org/10.1109/IECON.2006.347904

This paper proposes a new DC/AC power converter topology that is obtained by merging a buck type DC/DC converter and a DC/AC three-phase PWM Voltage Source Inverter (VSI) without the need of the passive components (smoothing inductor and capacitance)... Read More about A new two-stage voltage source inverter with modulated DC-link voltage and reduced switching losses.

A new three-level sparse indirect matrix converter
Conference Proceeding
Klumpner, C., Lee, M. Y., & Wheeler, P. (in press). A new three-level sparse indirect matrix converter. In IECON 2006 - 32nd Annual Conference on IEEE Industrial Electronics. https://doi.org/10.1109/IECON.2006.347958

Matrix converters are forced commutated single stage AC/AC direct frequency changers able to achieve sine wave in and out operation by being able to connect any input phase to any output phase via a 3x3 matrix of bi-directional switches. Indirect two... Read More about A new three-level sparse indirect matrix converter.

A new hybrid cycloconverter with smooth output voltage generation capability and accurate control of the circulating current
Conference Proceeding
Klumpner, C., Xu, T., & Clare, J. (in press). A new hybrid cycloconverter with smooth output voltage generation capability and accurate control of the circulating current. In IECON 2006 - 32nd Annual Conference on IEEE Industrial Electronics. https://doi.org/10.1109/IECON.2006.347850

Nowadays, power electronic converters based exclusively on IGBTs deliver excellent load side performance up to megawatt powers in the low voltage range (200-690V) and are steadily gaining performance in the medium voltage range as well. However, the... Read More about A new hybrid cycloconverter with smooth output voltage generation capability and accurate control of the circulating current.

A new three-level indirect matrix converter with reduced number of switches
Conference Proceeding
Klumpner, C., Lee, M. Y., Pitic, C., Wheeler, P., & Zanchetta, P. (in press). A new three-level indirect matrix converter with reduced number of switches. In 2007 IEEE Industry Applications Annual Meeting. https://doi.org/10.1109/07IAS.2007.28

Matrix converters are sine wave in/out forced commutated single-stage AC/AC direct frequency changers using a single bi-directional switch to connect any input to any output. Indirect two-stage matrix converters provide similar input and output perfo... Read More about A new three-level indirect matrix converter with reduced number of switches.

A new single-stage current source inverter for photovoltaic and fuel cell applications using reverse blocking IGBTs
Conference Proceeding
Klumpner, C. (in press). A new single-stage current source inverter for photovoltaic and fuel cell applications using reverse blocking IGBTs. In 2007 IEEE Power Electronics Specialists Conference. https://doi.org/10.1109/PESC.2007.4342251

Renewable energy sources such as photovoltaics (PVs) or fuel cells (FCs) are not fitted for direct power grid connection because they deliver DC voltage and current. This is why a power electronic interface is needed, consisting usually of a current-... Read More about A new single-stage current source inverter for photovoltaic and fuel cell applications using reverse blocking IGBTs.

A two-stage power converter for welding applications with increased efficiency and reduced filtering
Conference Proceeding
Klumpner, C., & Corbridge, M. (in press). A two-stage power converter for welding applications with increased efficiency and reduced filtering. In 2008 IEEE International Symposium on Industrial Electronics. https://doi.org/10.1109/ISIE.2008.4677248

The power supply technology used in welding applications changed dramatically from manually tap-controlled 50Hz bulky transformers which had large leakage inductance to provide stable arc burn to switch-mode fast controlled highfrequency power electr... Read More about A two-stage power converter for welding applications with increased efficiency and reduced filtering.

A more efficient current source inverter with series connected AC capacitors for photovoltaic and fuel cell applications
Conference Proceeding
Klumpner, C., Chonlatee, P., & Wheeler, P. (in press). A more efficient current source inverter with series connected AC capacitors for photovoltaic and fuel cell applications.

Renewable energy sources such as photovoltaics (PVs) or fuel cells (FCs) are not fitted for direct power grid connection because they deliver DC voltage and current. In addition, they also have a high internal resistance/nonlinear V/I dependence, whi... Read More about A more efficient current source inverter with series connected AC capacitors for photovoltaic and fuel cell applications.

Selecting the power electronic interface for a supercapattery based energy storage system
Conference Proceeding
Klumpner, C., Asher, G., & Chen, G. Z. (in press). Selecting the power electronic interface for a supercapattery based energy storage system. In 2009 IEEE Bucharest PowerTech. https://doi.org/10.1109/PTC.2009.5281965

This paper presents the initial investigations in selecting the topology of the power electronic interface for an energy storage system for power levelling applications based on a novel storage device, the supercapattery. The particularities of the s... Read More about Selecting the power electronic interface for a supercapattery based energy storage system.

A current source inverter with series connected AC capacitors for photovoltaic application with grid fault ride through capability
Conference Proceeding
Photong, C., Klumpner, C., & Wheeler, P. (in press). A current source inverter with series connected AC capacitors for photovoltaic application with grid fault ride through capability. In 2009 35th Annual Conference of IEEE Industrial Electronics. https://doi.org/10.1109/IECON.2009.5414954

The current source inverter (CSI) is preferred to interface a renewable source such photovoltaics (PV) to the AC power grid because it can provide smooth current source in the DC side, which fits to the PV behaviour and also steps-up the voltage from... Read More about A current source inverter with series connected AC capacitors for photovoltaic application with grid fault ride through capability.

Efficiency evaluation of a novel supercapattery stack with a power electronic interface for energy storage systems
Conference Proceeding
Kulsangcharoen, P., Klumpner, C., Zhou, X., Peng, C., Chen, G. Z., Rashed, M., & Asher, G. (in press). Efficiency evaluation of a novel supercapattery stack with a power electronic interface for energy storage systems.

The increase of renewable energy generation seen as the only way to ensure clean and sustainable development, is under scrutiny due to its intermittent nature and an insufficient development of com-plementary technologies such as electrical energy st... Read More about Efficiency evaluation of a novel supercapattery stack with a power electronic interface for energy storage systems.

A power electronic controlled dump load with negligible harmonics for accurate loading used in testing small wind turbines
Conference Proceeding
Klumpner, C., Al, B., & Hann, D. B. (in press). A power electronic controlled dump load with negligible harmonics for accurate loading used in testing small wind turbines. In 2010 IEEE International Symposium on Industrial Electronics. https://doi.org/10.1109/ISIE.2010.5637240

Permanent magnet synchronous generators (PMSG) are at the core of small scale wind power generators manufactured by a wide range of manufacturers in different configurations: vertical or horizontal axis blades, with various geometries and aerodynamic... Read More about A power electronic controlled dump load with negligible harmonics for accurate loading used in testing small wind turbines.