Improved Linear Active Disturbance Rejection Control of Photovoltaic Grid Connected Inverter Based on Filter Function

Aiming at the problem of noise easily polluting the voltage measurement link of an inverter DC bus in photovoltaic grid, an improved linear active disturbance rejection control technology based on filter function is constructed by combining linear active disturbance rejection control technology with filter. The core of the method is to expand the filtered voltage into a new state variable and use the linear extended state observer to estimate the filtered voltage, which is used as the feedback quantity, to improve the ability of linear active disturbance rejection control technology to suppress high-frequency noise. Then, considering that the output of the system contains noise, the frequency domain characteristics of the improved linear active disturbance rejection control are analyzed theoretically and verified by Bode diagram simulation. Finally, the feasibility and effectiveness of the proposed control strategy are demonstrated by building a simulation platform for grid-connected PV inverter.