Research On Predictive Direct Power Control Of Voltage Type Grid-Connected Inverter Based On Ladrc

Now that the energy crisis has become a major concern of the world,increasing the development and utilization of new energy has become an effective measure to solve the problem.In new energy power generation,photovoltaic grid-connected inverters as the core equipment have always been research hotspots.Based on the analysis of the inverter topology and traditional power control strategies,this subject proposes a linear active disturbance rejection control algorithm for power tracking compensation control in view of the internal uncertainty and external disturbances of the photovoltaic grid-connected system.In this paper,the three-phase voltage grid-connected inverter is taken as the research object,its working process and its topological structure are discussed,and its mathematical model is established.Secondly,the L-type filtering method is adopted as the grid-connected filter and the direct power control method is also adopted.By comparing the control effects of the traditional direct power control strategy and the direct power control strategy using the predictive model,it is found that the latter has the advantages of small static error,fast response and simple structure.Then,a simulation test was built for the prediction system.Analysis and research found that when the system is disturbed,that is,when the system’s line parameters deviate from the actual value,the system will produce static errors.In order to solve the problem of weak robustness of the control system,a second-order linear active disturbance rejection control model was established based on the grid-connected topology of the photovoltaic inverter,and its control parameters were analyzed and tuned.Starting from the frequency domain analysis,based on the closed-loop transfer function and frequency band characteristic curve of the linear active disturbance rejection controller,the tracking estimation ability of the linear extended state observer and the stability of the linear active disturbance rejection control system and the model uncertainty are discussed.The anti-disturbance capability under the natural conditions,the relationship between the control parameters and its dynamic characteristics is found.Then,the second-order linear active disturbance rejection controller is used to improve the robustness of the system.At the same time,the traditional disturbance observer control method is simulated and analyzed,and the performance of the linear active disturbance rejection controller is compared.Finally,a model and a d SPACE hardware-in-the-loop simulation system were built in Matlab/Simulink to simulate the predictive direct power control system using linear active disturbance rejection and the grid-connected operation experiment.The results show that the control strategy can quickly track the grid-connected current and effectively suppress disturbances.It shows the feasibility and practicability of the control strategy studied in this subject.