Parallel-connected resonant converter circuit and controlling method thereof

Abstract

The configurations of a parallel-connected resonant converter circuit and a controlling method thereof are provided in the present invention. The proposed circuit includes a plurality of resonant converters, each of which has two input terminals and two output terminals, wherein all the two input terminals of the plurality of resonant converters are electrically series-connected, and all the two output terminals of the plurality of resonant converters are electrically parallel-connected.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a parallel-connected resonant DC / DC converter circuit and a controlling method thereof, which can be employed to realize a current balance among converters when the switching frequencies of all the converters are the same.BACKGROUND OF THE INVENTION[0002]The developing trend of the DC / DC converter is just like that of the most of the power supply products, that is - - - high efficiency. The resonant DC / DC converter is easier to realize the high efficiency due to its feature of soft-switching. However, there are still certain existing drawbacks regarding the resonant DC / DC converter, e.g., the high ac current of the output filter of the series resonant DC / DC converter resulting in the high power loss and the large volume of the output filter.[0003]FIGS. 1(a)-1(d) are schematic circuit diagrams of several kinds of resonant DC / DC converter circuit. FIG. 1(a) shows a series resonant converter which includes a DC power source p...

AI Technical Summary

Benefits of technology

The present invention provides a parallel-connected resonant DC / DC converter circuit and a controlling method that can achieve current balance among the resonant converters when the switching frequencies of all the converters are the same. The circuit includes a plurality of resonant converters, each with two input and output terminals, which are electrically connected in parallel and in series with another. The circuit operates under an interleaved mode and can be controlled to achieve a balance between the specific converter and the remaining converters when the output current flowing through the specific converter reaches a certain ratio to the output current of the remaining converters. The technical effect of the invention is to enable a more efficient and balanced current distribution among the resonant converters, leading to improved performance and reliability of the parallel-connected resonant DC / DC converter circuit.

Problems solved by technology

However, there are still certain existing drawbacks regarding the resonant DC / DC converter, e.g., the high ac current of the output filter of the series resonant DC / DC converter resulting in the high power loss and the large volume of the output filter.

And since iD1 and iD2 have larger ripples, the ac current value of the output filter (output capacitor) Co is large which results in large size of Co and high power loss of the converter.

However, some problems still exist due to the characteristics of the resonant converters.

If the resonant converters are forced to operate in the same frequency, the current balance between the interleaved resonant converters is hard to be realized due to their different characteristics.

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