Development of an Improved Input-Parallel Output-Series Buck-Boost Converter and Its Closed-Loop Control

In this article, design and development of a new input-parallel output-series buck-boost converter (IOBBC) is presented, which produces high voltage gain, multiple output voltage, better efficiency, and exhibits lesser ripples in output voltage as well as in source current. IOBBC is based on the parallel-series combination of two different topologies of buck-boost converters (BBCs), where two converters operate in an interleaving state with 180° phase displacement during one complete switching cycle. The proposed converter produces noninverting output voltage unlike the conventional single switch based BBC and will produce wider range of output voltage even with a small change of duty cycle. A closed-loop controlled IOBBC has been fabricated utilizing a generalized optimized Type-III controller that has been designed by ``K-factor” method and particle swarm optimization technique for maintaining overall stability and to produce satisfactory dynamic response of proposed converter. IOBBC exhibits better performance than interleaved buck-boost converter in terms of voltage gain, efficiency, dynamic response, and ripple content in source current and in output voltage.