Research On Control Strategy Of Photovoltaic Grid-connected Inverter

The globe is experiencing a scarcity of energy supply and demand,as well as environmental deterioration,as a result of the fast expansion of the human economy and society.Because of its limitless qualities and low environmental impact,photovoltaic energy has captured the interest of several academics both domestically and internationally.However,the investment of nonlinear load and numerous power electronic devices has resulted in the injection of numerous harmonics at the common connection point between the photovoltaic grid.connected inverter and the power grid,which significantly lowers the power quality of the distribution network.As a result,one of the main areas of study for distributed generation is how to enhance the grid-connected PV system’s power quality.The current quality of solar power generation is determined by the safe and reliable functioning of grid-connected inverters,and inverter management is primarily determined by the grid-connected current control method.Consequently,the study topic of this work is the grid-connected current control technique of the solar grid-connected inverter.This paper models and analyzes six popular passive damping techniques by comparing inverters with three different topologies,uses the LCL inverter as the system’s topology,chooses filter parameters based on constraints,derives the mathematical model of the LCL inverter using various coordinate systems,decouples the model,and offers a theoretical framework for the investigation of subsequent control strategies.Based on the aforementioned study,a repeated control method based on the concept of internal mold is created for the solar grid-connected inverter.To test the effectiveness of the suggested tactic,the repetitive control theory is combined with PI control,the newly established control mode is established,the stability analysis is conducted,the inherent delay link is studied,the repetitive control theory is combined with PI control,and the newly established control mode is simulated.Analysis of the sliding mode variable structure control’s three qualities(reachability,stability,and invariance)is done in order to address the issue of repeated proportional control’s delayed dynamic reaction.,the inherent jitter problem of variable structure control is found and analyzed in detail,and it is suppressed by improving the approximation law,and then the repetitive control is linked with sliding mode control,and a control strategy weighted by repeated and sliding mode variable structure is proposed to carry out composite control of inverter.Improved dynamic response speed and robustness of the system.The weighted control strategy is then simulated and modeled in Matlab/Simulink,and the suggested control strategy’s steady.state and dynamic simulation analysis is conducted to confirm its performance in harmonic suppression and its resilience.The efficiency of the novel control technique suggested in this research is demonstrated by comparing the simulation results of the three control strategies mentioned above.The control method is then monitored in case of disruption by a change in DC voltage.Experiments are used to confirm the tracking speed and variation of the control system.