Title :
Parallel operation of charge-controlled DC-DC converters
Author :
Guerrero, Josep M. ; de Vicuna, Luis Garcia ; Miret, Jaume ; Matas, Jose ; Lopez, Oscar
Author_Institution :
Dep. d´Eng. de Sist. Automatica i Inf. Ind., Univ. Politecnica de Catalunya, Barcelona
Abstract :
In this paper, a charge control applied to parallel-connected DC-DC converters is proposed. Charge control is a kind of current-mode control, in which the integral of the inductor current in the on state of each switching cycle reaches a reference value. This value is the feedback output signal of a pole placement block, which fixes the poles of the output-voltage. Firstly, a charge controller is designed for a single DC-DC converter in order to show the benefits of this technique. Although the controller introduces a nonlinearity, the close-loop system output-voltage is near-linear under some conditions. The controller is studied for two different power distributed schemes: master-slave and democratic approaches. This control technique provides the following performances: tight output voltage regulation, robustness against external disturbances, and uniform distributed current sharing among modules. Besides, a fixed-frequency operation is achieved, being useful for active ripple cancellation methods, as the interleaving technique. On the other hand, the controller response against load current and line voltage step changes within one switching-cycle. The features of the proposed control scheme are verified through simulation results, confirming the theoretical analysis done.
Keywords :
DC-DC power convertors; closed loop systems; control system synthesis; electric current control; feedback; pole assignment; switching convertors; voltage control; active ripple cancellation methods; charge controller; charge controller design; charge-controlled DC-DC converters; close-loop system output-voltage; current-mode control; democratic approach; external disturbances robustness; feedback output signal; fixed-frequency operation; inductor current; interleaving technique; line voltage step changes; load current step changes; master-slave approach; nonlinearity; parallel-connected DC-DC converters; pole placement block; simulation; switching cycle; switching-cycle; tight output voltage regulation; uniform distributed current sharing;
Conference_Titel :
Industrial Electronics, 2002. ISIE 2002. Proceedings of the 2002 IEEE International Symposium on
Print_ISBN :
0-7803-7369-3
DOI :
10.1109/ISIE.2002.1025939