基于滑模变结构控制的直流微网DC/DC变换器

DC/DC Converter for DC Microgrid Based on Sliding Mode Variable Structure Control

直流微网运行时,如果母线电压变化较大,连接分布式电源和直流母线的DC/DC变换器在工作过程中,占空比会大幅度变化,使DC/DC变换器呈现严重的非线性,输出电压不稳定。针对这一问题,提出一种电压环采用基于比例切换的滑模变结构控制、电流环采用传统PI控制器的双闭环控制方案。仿真结果表明,本控制方案可以有效提高DC/DC变换器的鲁棒性,缩短过渡时间,抑制高频抖振,减小输出电压波动,满足高品质电能要求。

During microgrid running, if the change of bus voltage is very large, the duty cycle will have much more significant change during DC/DC converter connecting distributed source and DC bus running, which leads to serious nonlinear problem and unstable output voltage. To solve the problems, a double-closed-loop scheme composed by sliding mode variable structure control based on proportion switching in voltage loop and traditional PI control in current loop was adopted. Simulation results show that this control scheme can effectively improve the robustness of the converter, shorten the transition process, suppress the high frequency chattering, reduce the output voltage fluctuations, and meet the requirements of high quality performance.