A novel four-leg matrix converter

There is an increased interest in four-leg converters that can effectively provide the neutral connection in three-phase four-wire systems. This paper introduces a two-stage four-leg matrix converter, which can synthesise any desirable three-phase output line to neutral voltage. Two independent stages performing rectification and inversion are identified. The rectification stage is controlled to exhibit the highest voltage on the dc-rails. A three-dimensional space vector modulation technique is adopted at the inversion stage. Methods to reduce the neutral current and common mode voltage for the new topology are proposed.