Improved large signal performance of linear controlled input-series and output-parallel dc-dc converter using genetic algorithm optimization

An input-series and output-parallel (ISOP) connected converter is one of the recently developed multi- module converters. The suitable control scheme for this type of converter necessitates equal voltage sharing for input- series connected modules and output current sharing for the output-parallel connected modules for all operating conditions even with existence of dissimilarity in devices and components used in each module. Such control scheme consisting of several controllers can be implemented using analog controllers. This paper presents a genetic algorithm (GA) which optimizes the parameters of analog controllers for each control loop in the control scheme of an ISOP connected converter. Using GA eliminates the need for tedious and time consuming small signal analysis of multi- module converters. Moreover, because GA chooses the best value for each parameters in different control loops simultaneously it can best consider the interaction among all loops and results in better large signal performance especially in the case of large variations in the parameters or considerable difference among modules of converter.