双极性直流微电网的改进型高阶滑模自抗扰控制

针对双极性直流微电网中分布式新能源的系统功率波动、负载侧负荷频繁投切等不确定因素所引起母线电压波动问题，以基于风光互补含混合储能的双极性直流微电网为研究对象，提出一种双闭环改进型高阶滑模自抗扰控制策略。首先，依据自抗扰理论将控制系统拟合为一阶系统模型，转化为自抗扰控制系统范式。其次，设计了改进型超螺旋滑模控制器代替传统自抗扰控制中的线性控制器，引入了具有快速收敛性的级联有限时间扩张状态观测器代替线性扩张状态观测器，既能通过高阶滑模控制算法抑制抖振，又能提高对系统集总扰动的估计精度，从而利用非线性控制策略的优势改善系统动态响应过程及抗扰性能。然后，通过Lyapunov理论证明控制系统的稳定性。最后，基于Matlab/Simulink仿真软件以及搭建实验平台对3种不同控制策略进行对比验证，实验表明所提控制能够很好地抵抗扰动和提高系统的暂态性能。

Improved high-order sliding mode active disturbance rejection control for bipolar DC microgrids

There is a problem of bus voltage fluctuation caused by uncertain factors such as power fluctuation of the distributed new energy system and load frequent switching of load side in bipolar DC microgrid. Thus a dual-closed-loop improved high-order sliding mode active disturbance rejection control (ADRC) strategy is proposed for a bipolar hybrid energy storage DC microgrid based on wind-PV complementarity. First, the control system is fitted to a first-order system model and transformed into an ADRC paradigm. Secondly, an improved super torque sliding mode controller is designed to replace the linear controller in the traditional ADRC. A cascade finite time extended state observer (CFT-ESO) with fast convergence is introduced to replace the linear extended state observer. This can not only suppress the chattering using high-order sliding mode control algorithm and but also improve the estimation accuracy of the lumped disturbance of the system, thereby improving the dynamic response process and disturbance rejection performance of the system by taking advantage of thenonlinear control strategy. Then, the stability of the control system is proved by Lyapunov theory. Finally, Matlab/Simulink simulation software and an experimental platform are used to verify three different control strategies. The experiments show that the proposed control can both resist the disturbance well and improve the transient performance of the system.