Dynamic performance analysis of outer-loop current sharing control for paralleled DC-DC converters

For paralleling DC/DC converters, this paper investigates the fundamental relationship between the outer-loop current sharing control and the voltage regulation control. By using the concept of output impedance, the inherent function of the current sharing control is clarified and its influences on the voltage regulation of paralleling system are revealed. Although there may exist tradeoffs between dynamic current sharing and voltage regulation, it is possible to have good performances on both aspects, as long as the closed-loop output impedances of individual modules are within a certain tolerance range. After that, a design guideline for the current sharing compensator is proposed. The analyses and designs are verified by the simulation and experimental results.