DC/DC converter for high power DC grids

The present invention relates to a DC/DC converter which comprises a first bridge (Bridge 1) for connection via an inductor (L1) to a first DC power source (V1) and a second bridge (Bridge 2) for connection via an inductor (L2) to a second DC power source (V2). An AC transformer connecting the first and second bridges. The first bridge has a first branch having a pair of bi-directional switches, each including at least one IGBT semiconductor element, connected across the first power source and to a first terminal of the primary winding (Lac1) of the AC transformer, and a second branch having a pair of bi-directional switches, each including at least one IGBT semiconductor element, connected across the first power source and to a second terminal of the primary winding (Lac1) of the AC transformer. The second bridge has a first branch having a pair of bi-directional switches, each including at least one IGBT semiconductor element, connected across the second power source and to a first terminal of the secondary winding (Lac2) of the AC transformer, and a second branch having a pair of bi- directional switches, each including at least one IGBT semiconductor element, connected across the second power source and to a second terminal of the secondary winding (Lac2) of the AC transformer. Control means (100) provides square wave control signals to the semiconductor elements to enable a switching sequence of the semiconductor elements to provide differing current paths according to the type of first power source and second power source and direction of power transfer.