Input voltage imbalance compensation in peak current mode controled half bridge converters

Abstract

Instability of the input capacitors’ midpoint voltage has been observed to be one of the major obstacles ofimplementing the peak current mode control in symmetric half bridge converters. Slight variation of the voltage balance in input capacitors may cause serious damages to the operation of the half bridge converter leading total failure ofthe operation ofthe power converter. Some methods have been proposed in various papers some of them includes major changes in the power stage which requires specific application oriented design of some of the basic power stage components (ie: transformer) reducing the availability of components for custom designs. This analysis proposes simple but reliable solution to the aforesaid matter without applying any major modification to the power stage of the half bridge converter circuit and its hardware implementation. This discussion will also extend to analyze various instability phenomena’s possible in the peak current controlled half bridge converter applications in power conversion.