Modeling and Analysis of Buck-Boost Converter for Soft Charging Capacitive Loads

This work explores the modeling and design of small-scale drive circuits for dominantly capacitive loads such as electrostatic actuators (i.e. silicon, piezoelectric, and dielectric elastomer transducers) but is also applicable to other more general capacitor charging applications. A buck-boost converter (which can be used as a first stage to soft charge a second-stage switched capacitor (SC) converter) is designed and optimized to maximize capacitive charging and discharging efficiency with given timing constraints. The model is used to optimize converter operation and component selection. Simulation of the hybrid converter (buck-boost converter and SC converter) are presented. Experimental results of a buck-boost converter prototype are presented to verify the proposed model.