Decentralized Power Sharing of IPOP Buck Converters

Modular power conversion offers many technical and economic advantages as long as power sharing between modules is maintained. Power sharing through decentralized control (requiring no communication between modules and no central controller) offers the greatest flexibility. A droop-less decentralized control strategy has recently been demonstrated to achieve modular power sharing by incorporating nonlinearity in the integrator term in the control loop. This paper experimentally investigates the application of this control to input-parallel-output-parallel (IPOP) converters with buck output stages. It is found that converters with voltage-source-like characteristics at dc (such as voltage-mode CCM buck converters) require special consideration compared to other converters. The paper also explores the effect of this control on transient response. These features are demonstrated experimentally for voltage-mode and current-mode buck converters, including the effects of module-to-module variability.