Large-Signal Stabilization of Power Converters Cascaded Input Filter Using Adaptive Energy Shaping Control

Series connection of input filters with static converters might lead to instability. However, the input filter has rarely taken into account in the stable design of power converters. Indeed, an input LC filter cascaded with a converter can become unstable even if the converter is regulated by a tight controller ensuring its stability alone. This fact is due to the interactions between the filter and the converter. To tackle the instability potential, an adaptive energy shaping control (AESC), which is based on the interconnection and damping assignment passivity-based control (IDA-PBC), is addressed in this article to regulate the cascaded system and achieve the following attractive features: 1) the input filter's dynamics are considered in the control law, so the interactions between the filter and the converter are taken into account during the controller design and 2) the influence between several subsystems, put in cascade, is considered by the proposed method, and the new large-signal stability proof is given accordingly. Simulation and experimental results from a 3.5-kW, 270-200-V buck converter cascaded with an input filter under different load conditions, i.e., constant impedance load (CIL), constant current load (CCL), and constant power load (CPL), are presented to demonstrate the proposed approach.