A Robust Controller With Integrated Plant Dynamics for Constant Power Loads in DC MicroGrid

Abstract

Constant power loads (CPLs) pose a challenge for the control system of power electronic converters due to their negative damping characteristic. In this article, a fast and robust control system is introduced for a buck converter which can robustly feed and stabilize a dc bus with all kinds of loads, especially CPLs. The proposed controller properly takes advantage of the internal converter dynamics and removes the common integrating term used in the literature. In other words, the proposed controller does not increase the order of the control system. As a result, it provides a simple yet robust structure and performance, while at the same time provides a tight converter current-limiting feature. A simple two-step algorithm is presented to summarize the design stage of the controller, which only consists of two parameters. Detailed analyses, simulations, and laboratory-scale experimental results are presented to illustrate the desired performance of the proposed controller. The proposed controller is also compared with a state-of-the-art controller and its better performance is confirmed.