Robust Decentralized Voltage Control of DC-DC Converters with Applications to Power Sharing and Ripple Sharing

TL;DR

This paper proposes a robust decentralized control scheme for DC-DC converters that ensures voltage regulation and power sharing, including ripple sharing, using an equivalent single converter model and robust optimal control, without prior load information.

Contribution

It introduces a novel decentralized control architecture for multiple DC-DC converters that simplifies analysis via an equivalent single converter model and addresses ripple sharing and robustness.

Findings

Enhanced voltage regulation performance demonstrated.

Effective power and ripple sharing among sources.

Robust control design improves system resilience.

Abstract

This paper addresses the problem of output voltage regulation for multiple DC-DC converters connected to a grid, and prescribes a robust scheme for sharing power among different sources. Also it develops a method for sharing 120 Hz ripple among DC power sources in a prescribed proportion, which accommodates the different capabilities of DC power sources to sustain the ripple. We present a decentralized control architecture, where a nested (inner-outer) control design is used at every converter. An interesting aspect of the proposed design is that the analysis and design of the entire multi-converter system can be done using an equivalent single converter system, where the multi-converter system inherits the performance and robustness achieved by a design for the single-converter system. Another key aspect of this work is that the voltage regulation problem is addressed as a disturbance-rejection problem, where {\em unknown} load current is viewed as an external signal, and thus, no prior information is required on the nominal loading conditions. The control design is obtained using robust optimal-control framework. Case studies presented show the enhanced performance of prescribed optimal controllers.