1. Low-Voltage-Ride-Through Control of a Modular Multilevel Single-Delta Bridge-Cell (SDBC) Inverter for Utility-Scale Photovoltaic Systems.
- Author
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Sochor, Paul, Tan, Nadia Mei Lin, and Akagi, Hirofumi
- Subjects
ELECTRIC inverters ,PHOTOVOLTAIC power generation ,ELECTRIC potential ,ELECTRIC current converters ,ELECTRIC power production - Abstract
This paper presents theoretical and experimental discussions on low-voltage-ride-through operation of a modular multilevel single-delta bridge-cell (SDBC) inverter intended for utility-scale photovoltaic (PV) systems. Modern grid codes require grid-tied inverters to provide dynamic grid support during grid-fault events by injecting reactive current. This paper discusses decoupled positive- and negative-sequence reactive-current control, focusing on asymmetric voltage sags with imbalanced magnitude and phase relationships. The main objective is to present a feedforward control method based on calculation of the zero-sequence current required for achieving power balance during normal and grid-fault conditions. Moreover, this paper demonstrates a practical method that minimizes overcurrent stress in the three inverter clusters by adjusting active power drawn from PV arrays. Experimental results on a three-phase 12.6-kVA system prove that the SDBC inverter is capable of seamlessly operating through asymmetric voltage sags. [ABSTRACT FROM AUTHOR]
- Published
- 2018
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