Research On Grid-Connected Control And Low Voltage Ride Through Of Three-Phase Photovoltaic System

Its unparalleled advantages in the global boom of solar in the development of new energy, has become the hottest in the field of new energy resources. Currently, photovoltaic grid connected power is the most important form of the utilization of solar energy. So, how to improve the efficiency of photovoltaic power generation, and reduce the components of harmonic to feed energy into the grid purer. At the same time, require photovoltaic power plants in the grid voltage dips have the LVRT ability, the question boils down to what kind of control strategy photovoltaic grid-connected inverter.This article is a study of photovoltaic grid-connected inverter in the foundation of the internship of the Anhui Ming He new energy Co.Ltd. First, there is a simple analysis of the research status of photovoltaic power generation and LVRT technology at home and abroad in the current, classify and compare the structure of existing photovoltaic power generation system. Followed by analysis of a typical three-phase photovoltaic grid system works. Secondly, weighted average current control for photovoltaic grid-connected inverter, and Bode plots analysis, come join weighted average current factor controller more beneficial than the current feedback control scheme on low order harmonics filter. Thirdly, investigate a domestic and international basis LVRT control strategy is proposed based on first-order inertial filter positive sequence separation of phase-locked control, adding a first-order inertial filter links to avoid grid voltage drop due to traditional algorithm not the delay time of voltage phase-locked. In this paper, basis theoretical research, Three-phase photovoltaic grid-connectedsystems and positive sequence separation algorithm based first-order inertial filtering simulation, simulation waveforms show that the grid voltage drop, after separating the positive sequence voltage component quickly on the grid voltage phase-locked. Used of5kW PV inverter system module to do experimental research in Anhui Ming He new energy Co.Ltd. The experimental waveform output simulation waveform of this article,close to the standard sine wave, the better system performance proved that adding the weighted average current algorithm. But due to constraints, there is no further experiment technology of LVRT.