Grid Connected Photovoltaic Systems with SmartGrid functionality

Abstract

SummaryThis master?s thesis is focused on the design of grid connected PV power stage inverter. This inverter will be used for solar power application in the renewable energy laboratory at NTNU. The designed power stage inverter is a single phased 1kW, 230 V at the output. The DC/AC power stage converter is able to convert the minimum available voltage at the PV array of about 100V DC. The grid connected PV power stage inverter is designed in Multism and implemented in NI labView for simulation and analysis of output voltage and current.To achieve this goal, several literatures will be studied related to the work in this thesis. The choice of the best circuitry topology must be made and important parameters for the power stage inverter should be calculated/estimated. The control strategy for the power stage inverter shall be proposed and the expected desired output shall be analyzed in LabView and compared to the standard one (Grid output).Problem DescriptionAt NTNU a laboratory for renewable energy is under construction. This lab emulates several different renewable energy sources connected together. The power from the PV panels mounted outside on the building will be available for connection in the laboratory. A survey of control structures for the inverter when used as a grid connected PV inverter will be made. Based on this a suitable control will be chosen, which will include methods for grid synchronization, maximum power utilization, anti-islanding and current/voltage control. System models must be developed, which shall form a basis for controller parameter estimation. In the project the instrumentation system for collection of operation information of the PV plant into a database will be designed based on EtherCAT network. The purpose of this database is to collect and archive performance, reliability and operating cost data for this PV based distributed power systems.This thesis focused on the design of the single phase converter power stage. Important parameters for the inverter stage will be proposed. The converter is designed in Multism and implemented in LabView for the control of the output and user interface. The remaining task to accomplish the whole NTNU project in this laboratory will be the proposal of the control system.