Analysis of decentralized controller for multiple-input converters

This paper studies the close-loop multiple-input converters (MIC) stabilization through a decentralized controller. For an MIC, a multiple-input-multiple-output (MIMO) state-space representation can be derived by the averaging method. Based on the averaged MIMO model, an MIMO small-signal model can be generated. Both conventional method and multivariable frequency analysis are applied to the small-signal model of a multiple-input Single Ended Primary Inductor Converter (MI SEPIC) as a case study, in which the open-loop and closed-loop characteristics are explored. In addition to verifying the nominal stability and nominal performance, this work explores robust stability, and robust performance with the MΔ-structure. Although the analysis is motivated through a decentralized controller, the analysis of robust stability and performance can be extended to general cases. Simulations and experimental results verify the theoretical analysis and demonstrate that the decentralized PI controller is effective to regulate the output of an MIC under uncertainties.