基于高阶全驱动方法的直流微网恒功率负载下DC-DC降压变换器鲁棒控制器

The negative incremental impedance characteristics exhibited by constant power loads (CPLs) in dc microgrids introduce instability in upstream dc–dc buck converters. In this article, a robust control strategy based on high-order fully actuated system approach is proposed for globally stabilizing and regulating the buck converter feeding CPLs. First, a second-order fully actuated model incorporating nonlinear uncertainties from input, load and system parameters disturbances is derived to describe system dynamics. A robust control law is then synthesized from the perspective of second-order system dynamics by compensating for the negative effects introduced by CPLs and reconstructing the desired closed-loop dynamics through first-order state feedback. Second, an uncertainty boundary estimator is designed to enhance system robustness against disturbances without precise measurements of load or input. A simple differential state observer is adopted to avoid the use of noise-sensitive differentiators. The proposed controller not only ensures large signal stability of the system, but also achieves accurate tracking and fast dynamic response within a wide working range. Simulations and experiments are further conducted to validate the effectiveness and superiority of the presented controller.