Decentralized active disturbance rejection control of power converters serving a time varying load

In this article, the local trajectory tracking control problems -on the part of agents acting on a complex interconnection of nonlinear power converter subsystems- are reformulated as active disturbance rejection control (ADRC) problems. The new approach gives rise to a more effective and practical robust decentralized solution, with virtually no information on local plants interaction dynamics and limited knowledge of each subsystem model. It is shown that when the interconnection effects are viewed as exogenous, unstructured, disturbances, such disturbance can be actively estimated and canceled from each individual subsystem model dynamics, thus facilitating the accomplishment of the individual control objectives in a direct fashion. The case presented deals with two interconnected “Boost” DC-to-DC power converters feeding a time-varying current demand represented by a DC motor with uncertain load torque. Additionally each subsystem is subject to nonlinear uncertainty and strong interaction currents. The designed controller is shown to be robust with respect to interaction, un-modeled nonlinearities, and un-modeled dynamics.

1 Introduction

Decentralized control of interconnected, uncertain, nonlinear systems has been a challenging and important problem over the years. In recent times, the problem has gained renewed interest in the context of Power Electronics thanks to needs in efficient management of Renewable energy-based mini-grids as well as other important applications for DC-to-DC power Converters based low demand ecologically ori-ented, self-sustained, energy systems.