Direct AC-AC grid interface converter for ocean wave energy system

K. M. Tsang, Wai Lok Chan

Research output: Journal article publicationJournal articleAcademic researchpeer-review

5 Citations (Scopus)


Ocean wave energy is very promising. However, existing systems are using rectifying circuits to convert variable voltage and variable frequency output of electric generator into DC voltage and then use grid-tied inverter to connect to the power grid. Such arrangement will not only reduce the overall efficient but also increase the cost of the system. A direct AC-AC converter is a desirable solution. In this paper, a six-switch AC-AC converter has been proposed as a single phase grid-connected interface. New switching scheme has been derived for the converter such that the virtual input AC-DC conversion and the output DC-AC conversion can be decoupled. State-space averaging model and pulse width modulation scheme have been derived for the converter. As the input and the output operations can be decoupled, two independent controllers have been designed to handle the input AC-DC regulation and the output DC-AC regulation. The proposed scheme demands for two separate duty ratios and novel switching scheme has been derived to realize the combined duty ratios in one switching cycle. Power regulation, harmonics elimination and power factor correction control algorithms have also been derived for the converter when it is connected to the supply grid. Experimental results of a small scale model are included to demonstrate the effectiveness of the proposed switching and control schemes. Crown
Original languageEnglish
Pages (from-to)302-311
Number of pages10
JournalEnergy Conversion and Management
Publication statusPublished - 1 Mar 2015


  • Grid-connected converter
  • Ocean wave energy
  • Power conditioning

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Nuclear Energy and Engineering
  • Fuel Technology
  • Energy Engineering and Power Technology


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