Dynamic Analysis of Multimode Buck–Boost Converter: An LPV System Model Point of View

In dealing with the wide voltage range of energy storage components and fuel cell, multimode buck-boost converter (MBBC) serves as a versatile interfacing circuit with multimode operation capability. In this article, dynamic performance of MBBC is analyzed with consideration of converter operation under multiple modes, and a digital control design method is proposed for fast transient response. The dynamic analysis considers two influence factors, including “transition mode selection” and “close-loop control design.” The influences of different Transition mode have been analyzed with the aid of linear parameter varying system, and a new Transition mode has been proposed for the minimum polytopic working region. In “close-loop control design,” the recovery time has been minimized with guaranteed robust stability. Compared with small-signal design method, the proposed method not only ensures large-signal stability across multiple working modes, but also offers new insight for Transition mode selection which is overlooked in existing MBBC dynamic analysis. The designed controller has been applied for three representative transition modes, including the first proposed “double-buck-clamping” mode and comparatively evaluated with existing small-signal PI design method.