Switching Capacitor Assisted Buck-Boost Converter

Abstract

A switching capacitor assisted buck-boost converter is presented in this paper. This converter is capable of yielding a high buck-boost voltage gain at smaller duty ratios with maximum duty ratio range is up to 0.5. To achieve this, switching capacitor concept is used. Here, the capacitor switching action and interconnection with the inductance is enabled by the H-bridge which is formulated by a pair of controllable switches and diodes. A low-pass filter capacitor is used on the load side to ensure ripple free constant dc-voltage. Firstly, principle of operation is discussed followed by steady-state analysis is established. State-space models are derived to formulate the investigate the proposed converter behavior under dynamic conditions and then to design suitable controller. For concept validation and verification, a 15/48 V, 15/30 W prototype is constructed which is supplied from an input voltage of 24 V. Simulation and experimental results are depicted to demonstrate the proposed converter salient features.