Design and Analysis of Two-Switch-Based Enhanced Gain Buck–Boost Converters

Abstract

This article presents evolution of two-switch-based enhanced gain buck–boost converter (EGBBC) topologies. All these topologies exhibit quadratic buck–boost voltage transformation ratio together with common ground feature. The basis for these topological evolutions is the cascading of boost followed by restructured ZETA. Direct cascading of boost with ZETA yields a pseudo quadratic conversion ratio and an additional buck stage is mandatory to transform the gain to quadratic buck–boost form. Without adding additional stages and to yet realize the quadratic buck–boost transformation, a modified boost configuration at the front-end together with restructured cascading approach is adopted in the topological evolution. This evolution resulted in three different topologies exhibiting quadratic buck–boost voltage gain named as EGBBC Type-1, Type-2, and Type-3. Exhaustive steady-state and dynamic analysis is presented for Type-1, while brief formulations are listed for Type-2 and 3. Also, a comprehensive review of the reported buck–boost converters is made and compared with EGBBC features. A 10 ∼ 37 W, 15 to 10 V for bucking operation, and 75 V for boosting operation prototype is built for concept validation. A simple two-pole two-zero compensator is adopted for load voltage regulation. Measurement results demonstrate closed-loop system stability, robustness, and voltage regulation both in bucking as well as in boosting operation.