Chapter 2.PDF

This chapter aims to give a general description of the basic features of a three phase to three phase matrix converter in terms of performance and of technological issues. This chapter does not require to the reader a special knowledge of the matrix converter technology. It is worth noting that the three phase to three phase configuration is just one of the possible direct AC-AC converter topologies [1], which are not in the scope of the present report. The matrix converter has several advantages over traditional rectifier-inverter type power frequency converters. It provides sinusoidal input and output waveforms, with minimal higher order harmonics and no subharmonics; it has inherent bi-directional energy flow capability; the input power factor can be fully controlled. Last but not least, it has minimal energy storage requirements, which allows to get rid of bulky and lifetimelimited energy-storing capacitors. But the matrix converter has also some disadvantages. First of all it has a maximum inputoutput voltage transfer ratio limited to ≅ 87 % for sinusoidal input and output waveforms. It requires more semiconductor devices than a conventional AC-AC indirect power frequency converter, since no monolithic bi-directional switches exist and consequently discrete unidirectional devices, variously arranged, have to be used for each bi-directional switch. Finally, it is particularly sensitive to the disturbances of the input voltage system [2],[3]. The comments and remarks made in this chapter are somewhere supported by simulation results obtained from a simplified simulation model described in chapter 4.