Circuit theory of paralleling switching converters

Abstract

SUMMARYThis paper studies the various paralleling styles for dc-dc switching converters from a circuit theoretic viewpoint. The study begins with a systematic classification of the types of parallel-connected dc-dc converters. In the classification, converters are modeled as current sources or voltage sources. From Kirchhoff's laws, the possible connection styles for paralleling current sources and voltage sources are derived, leading to the identification of three types of configurations for paralleling dc-dc converters. Then, control arrangements are classified according to the presence of current-sharing and voltage-regulation loops. Moreover, detailed operating principles with and without a current-sharing loop for the three basic paralleling connections to obtain both current sharing and voltage regulation are given. Applying smallsignal analysis to the practical circuits, the inherent characteristics of each scheme are expounded. The roles of the current-sharing loop and origins of current-sharing errors are highlighted. Characteristics for all the schemes are obtained in terms of their performances in current sharing and voltage regulation. Finally, an experiment prototype is built to validate the analysis. The results clearly show the properties of the various paralleling schemes.

On/Off Control of Boost PFC Converters to Improve Light-Load Efficiency in Paralleled Power Supply Units for Servers

“…1) Each PSU handles the equal power of P O /2 by the loadshare controllers which are typically located at the output of the dc-dc stages [28]- [31].…”

“…Therefore, v LINK has a low-frequency ripple. From the fact that the instantaneous power flowing into v LINK is equal to the difference between instantaneous input and output powers, the peak-to-peak output-voltage ripple of the conventional scheme Δv LINK_conv and that of the proposed scheme Δv LINK_prop can be calculated as follows [31]:…”

Pulse current generator for driving tubular field emission lamp based on DCM flyback converter

“…Furthermore, the parasitic capacitance C p , which is resulted from the considerable turns in the secondary side, of the flyback transformer is considered in this paper. Besides, the proposed system is operated in DCM to raise the system efficiency 18–25. The sketch waveforms of the proposed pulse generator are shown in Figure 6, where the three operating states are described as follows, respectively.…”

“…Furthermore, the parasitic capacitance C p , which is resulted from the considerable turns in the secondary side, of the flyback transformer is considered in this paper. Besides, the proposed system is operated in DCM to raise the system efficiency [18][19][20][21][22][23][24][25].…”

Foldings and grazings of tori in current controlled interleaved boost converters

“…Power converters have to be connected in parallel whenever power conversion is necessary at a higher value of current than what the devices can carry [1][2][3][4][5][6]. By paralleling converters, the inductor current in each phase is reduced, and hence the size of the inductor can be decreased [1,[7][8][9][10]. This may be necessary in high-current applications like motor drives and battery chargers, and also in situations where the current carrying capacity of the switch is small, as is the case in on-chip power converters.…”