INTERACTION ANALYSIS AND CONTROLLER DESIGN FOR SINGLE- INDUCTOR DOUBLE OUTPUT DC-DC BOOST CONVERTER SYSTEM

Abstract

Single-Inductor Dual-Output (SIDO) DC–DC boost converters have gained significant importance in modern power-electronic applications because of their compact structure, reduced component count, improved power density, and capability of supplying multiple output ports using a common energy-storage element. However, due to the presence of a shared inductor, strong coupling and interaction exist between output channels, thereby making controller design and stable voltage regulation considerably challenging. The interaction between output channels significantly affects transient response, robustness characteristics, disturbance rejection capability, and overall converter performance. In this work, interaction analysis and decentralized controller design of a Single-Inductor Dual-Output DC–DC boost converter are presented. The proposed converter system is mathematically modelled using small-signal state-space analysis and represented in Multiple-Input Multiple-Output (MIMO) form. The interaction characteristics of the converter are investigated using Relative Gain Array (RGA), Dynamic Relative Gain Array (DRGA), Hankel Interaction Index Array (HIIA), singular value analysis and frequency-domain stability analysis. Based on the interaction behaviour, decentralized PID controllers are designed using reference-tracking, disturbance-rejection, and balanced tuning methodologies. Designed controllers are comparatively analyzed through the loop transfer function approach, decoupled channel approach, sensitivity function approach, Nyquist approach, and closed loop frequency response approach. Robustness and stability features of the converter are investigated during different working conditions. The performance of the proposed control schemes is verified by carrying out MATLAB/PSIM simulations. Comparative investigation of transient response, interaction mitigation, and robustness margins is conducted. The findings of the comparative study show that the balanced control scheme exhibits better damping characteristics, reasonable robustness margins, minimization of interaction gain, smooth transient response, and stabilization of output voltage regulation under load changes and tracking of the references.