Direct Current Bus Voltage Control of Photovoltaic Grid-connected Inverter Based on Improved Linear Active Disturbance Rejection

Traditional strategies for controlling the DC bus voltage of a photovoltaic grid-connected inverter cause large fluctuations in DC bus voltage and affect the stability of the system under various uncertain disturbance factors, such as time-varying disturbances and parameter perturbations. To solve this problem, an improved linear active disturbance rejection control (LADRC) strategy is proposed. First, the active power disturbance and the dual-loop control structure of the photovoltaic grid-connected inverter is described and the DC bus is dynamically modeled, second, the traditional LADRC is designed and, based on the traditional extended state observer (ESO) , the cascade ESO structure is used to improve the disturbance estimation suppression capability, Finally, the anti-disturbance and tracking terms in the cascade ESO are decoupled, which simplifies the controller parameter setting and further improves the anti-disturbance performance of the system. Theoretical analysis, simulation results, and hardware-in-the-loop experiments are used to verify the effectiveness and feasibility of the proposed strategy.