基于平坦理论的直流微电网双向DC-DC变换器改进滑模自抗扰控制

针对直流微电网系统中分布式电源功率波动、负载频繁投切以及不确定性扰动造成的母线电压波动问题，以直流微电网储能单元双向DC-DC变换器为研究对象，提出了一种基于平坦理论的改进滑模自抗扰控制策略。该方法采用双闭环控制结构，其中，电流内环采用微分平坦控制，提高系统的动态响应速度。在考虑系统抗扰性能和高频噪声影响的基础上，利用增阶滤波扩张状态观测器对外环模型总扰动进行估计。并根据状态量和扰动量估计信息设计了电压外环改进滑模自抗扰控制器，进一步提升系统的鲁棒性能。最后利用Matlab/Simulink软件进行仿真，验证了所提控制策略的有效性及优越性。

Improved sliding mode and active disturbance rejection control based on flatness theory for a bi-directional DC-DC converter in a DC microgrid

There can be bus voltage fluctuation caused by the power fluctuation of the distributed generation, and by the frequent switching of the loads and the uncertainty disturbance in a DC microgrid system. Thus an improved sliding mode and active disturbance rejection control based on flatness theory is proposed with the bi-directional DC-DC converter of a DC microgrid energy storage unit as the research object. The method adopts the double closed-loop control structure, in which the current inner loop adopts differential flatness-based control to improve the dynamic response speed of the system. Considering the system immunity performance and the influence of high-frequency noise, the total disturbance of the outer loop model is estimated using an increased-order filter extended state observer. The improved sliding mode and active disturbance rejection controller of the voltage outer loop is designed based on the estimation information of state and disturbance quantities to further improve the robustness of the system. Finally, the results of simulation built by Matlab/Simulink demonstrate the validity and superiority of the proposed control scheme.

This work is supported by the National Natural Science Foundation of China (No. 51777167).