Matrix Converter-Based Active Distribution Transformer

Abstract

This paper proposes a matrix converter-based active distribution transformer (MC-ADT) with enhanced control functionalities to be used in smart grids (SG). The proposed MC-ADT uses a matrix converter (MC) connected to a transformer inserted in series with the grid, and allows: 1) real-time voltage regulation of the low-voltage side of the MC-ADT, based on an adjustable reference value defined by the SG requirements and bounded by the standard values; 2) capability to regulate the LV grid voltage even in case of sags, voltage rises, and overvoltages in the transformer medium-voltage side; and 3) contribution to power factor correction in the MV side. The MC-ADT grid voltage regulators are synthesized, establishing the MC reference currents. To guarantee the tracking of the MC input and output reference currents, the space vector representation, together with sliding-mode direct control techniques, are used. The obtained experimental and simulation results show that the proposed system is able to regulate the LV grid voltages even for sags and overvoltages up to 20% in the MV side, and contributes to power factor correction in MV, while presenting fast dynamic response, without overshoot and almost zero steady-state error.