Power balance control for a two-stage solar inverter with Low Voltage Ride Through capability

Kampitsis, Georgios, Batzelis, Stratis and Papathanassiou, Stavros A. (2016) Power balance control for a two-stage solar inverter with Low Voltage Ride Through capability. 32nd European Photovoltaic Solar Energy Conference and Exhibition (EU PVSEC 2016), , Munich, Germany. 20 - 24 Jun 2016. (doi:10.4229/EUPVSEC20162016-5CO.15.2).

Record type: Conference or Workshop Item (Paper)

Abstract

The latest grid codes require the renewable energy sources (RES) to provide ancillary services during fault and post fault conditions. More specifically, in case of a short-duration voltage dip, the grid-tied photovoltaic (PV) system should stay connected and support the grid by injecting reactive power. However, meeting these requirements during voltage sags is a challenge for two-stage systems, due to the power imbalance between the dc/dc converter and the inverter, resulting in dc-link voltage excursions and output current overshoots. In this paper, a power balance control scheme is proposed, by which, a successful low voltage ride through (LVRT) and smooth dclink voltage variation are achieved, while the output current is kept within the predefined limits. Two reactive power injection strategies are investigated that exhibit different dynamic response during voltage sags. The effectiveness of the proposed LVRT control is verified though simulations of a 2 kVA solar system.

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Kampitsis - Power balance control for a two-stage solar inverter [accepted] - Accepted Manuscript

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