H∞ loop-shaping of a multi-input dc-dc converter using weight function parameter optimization

Abstract

Designing of controllers for Multi-Input DC-DC Converter (MIDDC) topology is a challenging task due to control loop interactions. Most of the closed loop controllers designed for MIDDC topologies are by considering the interactions measures of the closed loops. In this article a non-isolated MIDDC converter with a compact structure is chosen and designing of robust controller using Loop Shaping Design (HILSD) methodology and is interaction independent. Stabilizing controller design require the selection of the weight function parameters, if the selection of weight function parameters is not chosen properly in designing of controller it may not achieve reasonable compromise between robust performance and robust stability. So, for better the design efficacy of HILSD, a weight function optimization problem is formulated where, Frequency Integral Square Error (FISE) based performance index is used as objective function, however the performance level of the designed controller which regulates MIDDC converter system and success of loop-shaping procedure are used as constraints. Global search algorithm has been used in this work to find the global optimum weight function parameters and these are obtained in MATLAB environment. Effectiveness of MIDDC converter is verified viz. simulation in PSIM environment with HILSD controller for the regulation of load voltage as well as load division by considering a 100 W, 36 V/12 V to 24 V dc power converter.