QFT Based Multi-variable Controller Design For Buck, Boost Based Double-Input DC-DC Converter

In this paper, a quantitative feedback theory (QFT) based robust controller is designed for double-input DC-DC converter. Relative gain array (RGA) based interaction analysis is used for determining the controlling inputs and controlled outputs pairing. A charge-pump based double-input DC-DC converter is used as an example to explain the QFT robust diagonal controller design methodology. Performance specifications are enforced to handle the parametric uncertainties. For stable and reliable power management, two control-loops are adopted. One for current control and another for load voltage regulation. A 60/24 V to 48 V, 100 W 50 kHz double-input converter system is considered to demonstrate the QFT based multi-variable controller design. Effectiveness of diagonal controller pair is investigated through simulations and found that the results are in close agreement with analytical studies.