A large signal averaged modelling and control of paralleled DC/DC converters with automatic load sharing

This paper presents a unified method for developing power stage transfer functions of paralleled DC/DC converters employing automatic load sharing control. The proposed technique uses large signal averaged models to derive the steady-state and small signal transfer functions, instead of employing small signal modeling technique used widely in literatures. The proposed approach is general and can be applied to any number of paralleled modules. For illustration purpose, this modeling method is applied to two paralleled buck converters with automatic load sharing control, and the corresponding large signal characteristics are analyzed. Moreover, a design methodology for the Current Share (CS) compensator based on the current share loop gain has been presented. Stability and dynamic performance of the CS control are studied. Simulation results of three paralleled Buck converter converting the input DC voltage of 12 V, to 5 V DC at 3x20 A are presented in order to verify the theoretical approach reported in the paper.