Improving micro-grid power quality using three-phase four-wire active power conditioners

In this paper is presented a comparative analysis between two power conditioners connected to a four-wire micro-grid. The first one was developed on a two levels voltage structure and the second one on a three-level voltage NPC structure (Neutral Point Clamped), both controlled by the same strategy. The main objective of the proposed strategy is to limit the disturbance produced by different loads. Another goal is to act as an interface between renewable energy sources and the micro-grid. In this study, about 25% of the power requested by the load comes from the renewable energy sources. The investigated systems have been implemented in Matlab / Simulink, in order to analyze the micro-grid harmonic level, the power factor and the voltage unbalance at the point of common coupling.