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

抄録

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.