Control Of Grid Connection For Residential Wind Power System

Grid-connected inverter plays an important role in distributed resource such as wind power system and so on, which is accepted as being self-evident.It is a significant way to build a Variable speed constant frequency wind power system that by means of a electronic power converter——grid-connected inverter to completely decouple rotor speed of the generator and the frequency of the grid.Systemic discussions about the theory and detailed researches on the realization of single-phase grid-connected inverter in small wind power systems are made in this paper. Usually, these systems shall detect the island and ceased to work after utility failure without exceeding the time limit and only output power when the utility is under a good condition according to the corresponding standards, in which the time limit and power quality demands are always clarified. The dc voltage is usually no more than 400Volt, and inverters are connected to the household utility via appropriate filter circuit. The appropriate control strategy is applied to energize the utility with unit power factor. The voltage of dc bus is set as 360 Volt and LC filter is chosen for this paper.The overall problems of single-phase grid-connected inverter was described, mainly including tracking strategy for sinusoidal current reference, consideration about LC filter parameters, ways to acquire grid phase and anti-islanding strategy in this paper. PI combined with hysteresis regulator is adopted in this paper, and gird phase is achieved by zero crossing detection method, specifically, the crossing from negative to positive of the grid voltage. Firstly, brief introductions are made about the principle of grid-connected inverter system, selection guide for LC filter parameters and mainly used control strategy. Then, simulation result is given for the proposed control strategy using Matlab/Simulink. Further, the corresponding hardware and software are designed to validate the chosen methods with a brief explanation. Finally, under the protection of passive anti-islanding methods, the experiment is made to validate the proposed strategy used in this paper. The experiment result shows that the goal of outputting power with unit power factor is basically achieved on its good aspect, but the power quality needs further improvement. Further analyses and discussions are also given on the problems arising from the experiment.