Dr Pat Wheeler, Dr Jon Clare, Dr Lee Empringham, Mr Maurice Apap and Mr Michael Bland
School of Electrical and Electronic Engineering University of Nottingham, Nottingham, UK Tel. +44 (0) 115 951 5591, Fax. +44 (0) 115 951 5616, email. Pat.Wheeler@Nottingham.ac.uk
SUMMARY Recently there has been considerable interest in the use of matrix converter technology for motor drive applications, with particular interest being shown by Siemens, Rockwell and Yaskawa. This paper gives an introduction to matrix converter technology and investigates the suitability and design of matrix converters for industrial applications. The potential advantages of matrix converter technology are examined and the factors that have so far prevented commercial exploitation of the circuit are discussed. The remaining technical challenges are defined and the work in progress to meet these challenges is highlighted.
1. INTRODUCTION The matrix converter offers an all silicon solution for AC-AC power conversion. The circuit consists o an array of hi-directional switches arranged so that any of the output lines of the f converter can be connected to any of the input lines. Figure 1 shows a typical three-phase to threephase matrix converter, with nine bi-directional switches. The switches allow any input phase to be connected to any output phase. The output waveform is then created using a suitable PWM modulation pattern similar to a normal inverter, except that the input is a three-phase supply instead of a fixed DC voltage. This approach removes the need for the large reactive energy storage components used in conventional inverter based converters. An input line filter is included to circulate the high frequency switching harmonics.
Figure 1 - A three-phase to three-phase matrix converter circuit
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Table 1
The matrix converter has many advantages over traditional topologies. It is inherently bidirectional so can regenerate energy back to the supply.