Novel analog adaptive 3-loop average current mode control of parallel DC-DC converters

A new three-loop control scheme for multimodule parallel DC-DC converters with average current mode control (ACC) is presented. The proposed loop adds a high gain robust loop with two controllers to the conventional current and voltage ACC loops, achieving an analog adaptive voltage loop in which the equivalent voltage regulator varies with the changing power stage parameters: number of modules, input voltage, load and component tolerances. The loop improves drastically the disturbance rejection of the control system, i.e. closed loop output impedance and audiosusceptibility, while preserving stability and loop gain crossover frequency to a significant extent.