A Dual-input Boost-Buck Converter with Coupled Inductors for TEG Applications

A dual-input Boost-Buck converter with coupled inductors (DIBBCI) is proposed for thermoelectric generator (TEG) power system, where low current ripple under wide input voltage range is required for the converter. The DIBBCI is constructed by cascading two Boost cells with a Buck cell, and the filter inductors of the Buck cell is composed of two inductors, which are inverse-coupled with two filter inductors of Boost cells. Reduced size and power loss of the filter inductors are achieved benefiting from the DC magnetic flux cancellation. A control strategy for free and seamless modes transfer among constant-voltage, constant-current and distributed maximum power point tracking (MPPT) are also proposed. The operational principles, the influence of the coupled inductors and design considerations are analyzed in detail. A 450W prototype is built with experimental results given to verify the analysis.