| With the topic of clean energy being mentioned again,solar photovoltaic grid-connected power generation systems have attracted much attention.Grid-connected inverter technology is one of the most important.Among them,the resonance problem often accompanies the grid-connected inverter,which will cause the current in the system to be distorted.At the same time,it will cause the instability of the power quality.Resolving the resonance problem is a very crucial link at present.In this paper,the topological structure of LCL filter and dual closed-loop control system are used to filter out the high frequency harmonics of the output voltage of the inverter bridge arm.At the same time,the active damping method is adopted.After the feedback of the capacitor current,the resonance peak is suppressed.Distortion of the current,using a visualization algorithm to select the range of PI parameters.The research work of this paper is as follows:1.This article analyzes L-type,LC-type,LCL-type filters of three different orders,from their basic topology circuit,mathematical model and transfer function for comparative analysis,and application of simulation software Matlab to obtain their respective Bode diagram Through the comparison between the two,the respective filtering characteristics were analyzed.2.Developed the structure of the inverter,the parameters of the LCL filter,the damping method to study the resonance suppression,mathematical modeling and analysis of the double closed-loop control system of the LCL grid-connected inverter,using the frequency domain and time domain performance Constraints,through the visual algorithm to obtain the PI parameter value range.3.The experimental system was designed,and the LCL single-phase and three-phase grid-connected inverter system simulation platform was built using Matlab/Simulink,and the stability of the system and the harmonic content of the output waveform were analyzed.System and control method design feasibility. |
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