Research

PhD research work

• Title : Hybrid Direct AC/AC Power Converters
• Objectives :
  to investigate novel hybrid ac/ac direct power converter structures based on two-stage matrix converter in order to improve the voltage transfer ratio and robustness to the supply voltage disturbances
• Supervisors : Dr. Christian Klumpner and Dr. Patrick Wheeler
• Expected finishing date : October 2006
• Abstract :
  AC/AC Direct Power Converters (DPC) deliver variable frequency variable voltage to a load without using any intermediate energy storage devices. Matrix Converters (MC) offer sinusoidal supply currents, adjustable input displacement power factor irrespective of the type of the load and bidirectional power flow apart from being a DPC. Absence of energy storage devices such as electrolytic capacitors enables the MC to increase its power density and to offer longer life span. Lower immunity to supply voltage disturbances and limited voltage transfer ratio (theoretically 86%) are the main disadvantages of matrix converters. Therefore the research focuses on investigating hybrid structures based on matrix converter topologies in order to improve the voltage transfer ratio and provide higher robustness against supply voltage disturbances.

Publications

• T. Wijekoon, C. Klumpner, P. Wheeler,'Implementation of a Hybrid AC/AC Direct Power Converter with Unity Voltage Transfer', accepted to be presented in the IEEE Applied Power Electronics Conference APEC'06 , March 19-23 2006, Dallas, USA.


• T. Wijekoon, C. Klumpner, P. Zanchetta, P. Wheeler, 'A Predictive Current Controller Scheme for a Hybrid AC/AC Direct Power Converter', accepted to be presented in the IEE Power Electronics, Machines and Drives Conference PEMD'06, April 4-6 2006, Dublin, Ireland.


• T. Wijekoon, C. Klumpner, P. Wheeler, 'Improvement of Output Voltage Capability of a Two Stage Direct Power Converter Under Unbalanced Input Voltages', 11th European Conference on Power Electronics and Applications EPE'05, September 11-14 2005, Dresden, Germany, paper #0597 on CD-Rom.


• C. Klumpner, T. Wijekoon,, P. W. Wheeler, 'A New Class of Hybrid AC/AC Power Converters,', IEEE Industrial Application Society IAS'05, 40th Annual General Meeting, October 2-6 2005 Hong Kong, paper #67p5.


• C. Klumpner, T. Wijekoon, P. W. Wheeler, 'Active Compensation of Unbalanced Supply Voltage for Two-Stage Direct Power Converters Using the Clamp Capacitor', IEEE Power Electronic Specialists Conference PESC'05, 12-16 June 2005, Recife, Brazil.


• C. Klumpner, T. Wijekoon, P. W. Wheeler, 'New Methods for the Active Compensation of Unbalanced Supply Voltages for Two-Stage Direct Power Converters', International Power Electronics Conference IPEC-2005, 4-8 April 2005,Niigata, Japan, paper #0461 on CD-Rom, 2005.


• P.T.B. Wijekoon, R.M.S.Lenagal, C.K. Walgampaya, S.L. Dharmasena, 'Computer Based Fetal Monitoring System", IEE Ninth Annual Conference organized by the IEE Sri Lanka on 28th September 2002.


• P.T.B. Wijekoon, S.G. Abeyratne, "Low cost efficient emergency CFL lighting system", Annual Research sessions 2002, University of Peradeniya, 30th October 2002.