风电并网逆变器的改进型线性自抗扰控制

Improved Linear Active Disturbance Rejection Control of Wind Power Grid-connected Inverter

针对并网逆变器控制中传统电压电流双闭环控制策略抗扰能力不足的问题,构造线性自抗扰控制(LADRC)取代电压外环控制。为了提高线性扩张状态观测器(LESO)的观测精度,通过在LESO中引入直流母线电压微分与其观测值之间的误差项,对传统LADRC进行了改进。从频域分析上证明了改进型LADRC的跟踪性能和抗扰性能均优于传统LADRC。仿真结果表明,所提出的改进型LADRC可确保并网逆变器具有更好的稳态与暂态性能,特别是在电网电压跌落和负载突变方面具有优越性。

Aiming at the problem of insufficient anti-disturbance capability of traditional voltage and current double-closed-loop control strategy in grid-connected inverter control,a linear active disturbance rejection control(LADRC)was constructed to replace voltage outer-loop control.In order to improve the observation accuracy of linear extended state observer(LESO),the traditional LADRC was improved by introducing the error term between the DC bus voltage differential and its observation value into LESO.It was proved that the tracking performance and anti-interference performance of the improved LADRC are better than that of the traditional LADRC from the frequency domain analysis.The simulation results show that the improved LADRC can ensure the grid-connected inverter has better steady-state and transient performance,especially,it has advantages in voltage sag fault and sudden load change fault.