Research On Single Phase PV Grid-Connected Inverter

Inverter is the key interface between the PV array and the power grid, which influences a lot on the general performance. The power stage topology, the filter and the control strategy should be designed carefully to maximize the energy fed back to the utility to enhance the stability, reliability and accuracy.First of all, a survey is made on the state-of-the-art developments and applications of the PV power system. Besides, the types and structure of the PV system including the standard for the utility-connected is summarized in this thesis. By detailed comparison with the existing topologies, the configuration and parameter for a 1kW/ 220V interconnected inverter are proposed. The output filter design and some related characteristic analysis are also given.Secondly, some different control strategies for the PV inverter are analyzed, resulting in the instant voltage mode for stand-alone and the instant current mode for interconnected operation, respectively. Modeling and loop parameter design are made along with system simulation by Saber to confirm the control validity.And then, usual MPPT (Maximum Power Point Tracking) algorithms are summarized and compared after analysis of PV array performance. Perturbation and observation method is adopted to realize the MPPT. The corresponding design proceedure and experiments are presented.Finally, according to the results of analysis, an experimental prototype is developed with DSP, and the experiment results are given to verify the theoretical analysis.