Research on bus voltage control strategy of DC side of wind power grid-connected inverter

In order to improve the anti-disturbance performance of the direct current (DC) bus voltage in wind power grid-connected system, a new double closed-loop structure based on improved linear active disturbance rejection control (LADRC) is proposed. The characteristic of the improved LADRC is that it introduces proportional derivative (PD) control to the gain coefficient of the observation total disturbance signal in the traditional linear extended state observer (LESO). According to the prediction function of differential control, it produces an advanced control effect and improves the disturbance observation ability of LESO. Frequency domain analysis shows that the improved LADRC has better anti-disturbance performance. The improved LADRC is applied to the voltage and current double closed-loop control of wind power grid-connected converter. The simulation results show that the DC bus voltage based on double closed-loop structure with improved LADRC has better anti-disturbance performance when the grid voltage changes suddenly than the double closed-loop structure with LADRC.