Bi-directional dc-dc converter

Abstract

The present invention relates to a bi-directional DC-DC converter comprising: a first terminal, a second terminal, a transformer circuit, a first high voltage side coupled to said first terminal, and a second low voltage side coupled to said second terminal; wherein said first high voltage side and said second low voltage side are coupled to each other by means of said transformer circuit, and said first high voltage side comprises a resonant tank circuit coupled between a first bridge circuit of said first high voltage side and a high voltage side of said transformer circuit. Furthermore, the invention also relates to a system comprising at least two such bi-directional DC-DC converters.

What is claimed is: 
     
         1 . A bi-directional DC-DC converter, comprising:
 a first terminal circuit;   a second terminal circuit;   a transformer circuit;   a first high voltage side coupled to the first terminal circuit; and   a second low voltage side coupled to the second terminal circuit;   wherein the first high voltage side and the second low voltage side are coupled to each other via the transformer circuit; and   wherein the first high voltage side comprises a resonant tank circuit coupled between a first bridge circuit of the first high voltage side and a high voltage side of the transformer circuit wherein the resonant tank circuit comprises:   a first branch comprising a first capacitor C r2  and a first inductor L r1  coupled in series;   a second capacitor C r2 ; and   a second inductor L r2 ;   wherein the first branch, the second inductor L r2  and the second capacitor C r2  are coupled to a common node;   wherein the second capacitor C r2  is coupled between the common node and a first terminal of the high voltage side of the transformer circuit; and   wherein the second inductor L r2  is coupled between the common node and a second terminal of the high voltage side of the transformer circuit;   wherein:   a first terminal of the first capacitor C r1  forms a first terminal of the resonant tank circuit;   a second terminal of the first capacitor C r1  is connected to a first terminal of the first inductor L r1 ;   a second terminal of the first inductor L r1  is connected to a first terminal of the second capacitor C r2  and to a first terminal of the second inductor L r2;      a second terminal of the second inductor L r2  forms a third terminal of the resonant tank circuit; and   a second terminal of the second capacitor C r2  forms a second terminal of the resonant tank circuit.   
     
     
         2 . The bi-directional DC-DC converter according to  claim 1 , wherein:
 the first terminal of the resonant tank circuit and the third terminal of the resonant tank circuit are connected to the first bridge circuit; and   the second terminal of the resonant tank circuit and the third terminal of the resonant tank circuit are connected to the high voltage side of the transformer circuit.   
     
     
         3 . The bi-directional DC-DC converter according to  claim 1 , wherein:
 the first bridge circuit is a full bridge and the second low voltage side comprises a further full bridge coupled to a low voltage side of the transformer circuit; or   the first bridge circuit is a half bridge, the second low voltage side comprises a push-pull circuit connected to the low voltage side of the transformer circuit and the transformer circuit comprises on its low voltage side a second winding comprising a center tap; or   the first bridge circuit is a half bridge and the second low voltage side comprises a push-pull circuit with an autotransformer connected to the low voltage side of the transformer circuit.   
     
     
         4 . The bi-directional DC-DC converter according to  claim 1 , further comprising:
 a first filter coupled in parallel with the first bridge circuit.