Control of buck-boost direct matrix converter with low voltage ride-through capability

This paper proposes a closed loop grid side control of the direct matrix converter with V-connection AC chopper controlled by the classical field orientated control of an induction machine. The presented approach enables ride-through capability during grid voltage sags. Additionally, the reactive grid current can be controlled independently from the active grid current. Thus, this direct converter becomes an attractive topology for distributed energy systems with low mass and high power density requirements. The control performance at machine operation point changes as well as the transient behaviour at symmetrical and unsymmetrical grid failures is discussed.