The Research Of Distributed Power Interconnection Control Strategy

21st century, energy supply is tension, the people focus on how to make more efficient use of the clean energy, in recent years, distributed generation and grid technology has made rapid progress. However, many electricity experts recognized that the form of the large power grid combined with distributed power can be saving energy, improving reliability and flexibility of power system, it is the forward direction of the electric power industry. Therefore, it is an important meaning to research the distributed power grid.First of all, established three kinds of Distributed Power mathematical models and analyze its characteristics and net principle, build up the mathematical model of the photovoltaic power and analysis its output characteristics, research the technology of the maximum power point tracking. Use improved optimization incremental conductance method to solve the problem of the conventional variable step incremental conductance method become invalid under the change of the external environment, verify that this method can accurately and quickly tracking the change of the external conditions, take into account the steady-state accuracy and the tracking speed, the effect is perfect. Secondly, analyze the network theory and control structures based on PI controller, focuses on the performance of the controller, find out the fundamental frequency gain is small and the control effect is insufficient. Introduce quasi-PR controller with formula, ameliorate control algorithm to improve the control effect, make out bode diagram of the closed loop transfer function to valid that the control performance is satisfactory. Finally, establish the model of the single-phase grid-connected inverter system to research grid connection control strategy, set up a control block diagram and analysis the principle of the inverter circuit, the inverter systems use two-loop control strategy and put quasi-PR controller in the inner ring, make use of the simulation experiment to verify this control strategy is correct and feasible, the control effect is good, dynamic response is fast. Inverter output high quality sine wave current to same as the grid voltage frequency and phase, proved that the dual closed-loop control strategy can achieve the purpose of transfer high quality power to the grid.