A direct AC/AC converter based on current-source converter modules

The research on direct ac/ac conversion in the past twenty years has been following two major directions: 1) improving the performance of the original nine-bidirectional-switch matrix converter topology; 2) using converter topologies composed of unidirectional switches only. In this paper, a direct ac/ac converter topology based on current-source converter modules is proposed. It is shown, through analysis and simulation, that the proposed topology is free of any switching difficulties and gives high-quality sinusoidal waveforms on both sides. Furthermore, with the same number of semiconductor devices as in the original nine-bidirectional-switch matrix converter topology, it is able to perform all aspects of frequency changing, real power flow control, and independent reactive power flow control on both sides. The proposed topology finds applications in electric drive industry, as an ac motor drive, and power system industry, as an asynchronous link. Index Terms--AC/AC converter, CSC, frequency changer, high-quality sinusoidal waveforms, independent reactive power flow control, L-C filter, nine-bidirectional-switch, NPT IGBT, real power flow control, semiconductor devices, SVC, THDs, topology.