An electric power converter comprising: a first power converter stage configured to transfer power between its first port and second port; a second power converter stage configured to transfer power between its first port and second port; a first transformer which has a first side and a second side; a second transformer which has a first side and a second side; a multi-bridge circuit connected to the second side of said first transformer and the second side of said second transformer, wherein the multi-bridge circuit comprises three bridges and has a direct current terminal; the first power converter stage having its first port connected to the first side of the first transformer; the second power converter stage having its first port connected to the first side of the second transformer; the multi-bridge circuit comprising a first terminal connecting both ends of the second side of the first transformer to the midpoints of a first pair of bridges of the multi-bridge circuit, and a second terminal connecting both ends of the second side of the second transformer to the midpoints of a second pair of bridges of the multi-bridge circuit; and a controller coupled to the multi-bridge circuit, the first power converter stage, and the second power converter stage, wherein the controller is configured to operate the multi-bridge circuit in a parallel mode in which the second sides of the first and second transformers are switched in parallel to at the DC terminal resulting in a first voltage at the DC terminal being equal to both a second voltage on the side of the first transformer and a third voltage on the side of the second transformer; characterised in that: the controller is further configured to operate the multi-bridge circuit in a series mode in which the second sides of the first and second transformers are switched in series to the DC terminal resulting in a fourth voltage at the DC terminal being a summation of a fifth voltage on the second side of the first transformer and a sixth voltage on the second side of the second transformer. a first power converter stage configured to transfer power between its first port and second port; a second power converter stage configured to transfer power between its first port and second port; a first transformer which has a first side and a second side; a second transformer which has a first side and a second side; a multi-bridge circuit connected to the second side of said first transformer and the second side of said second transformer, wherein the multi-bridge circuit comprises three bridges and has a direct current terminal; the first power converter stage having its first port connected to the first side of the first transformer; the second power converter stage having its first port connected to the first side of the second transformer; the multi-bridge circuit comprising a first terminal connecting both ends of the second side of the first transformer to the midpoints of a first pair of bridges of the multi-bridge circuit, and a second terminal connecting both ends of the second side of the second transformer to the midpoints of a second pair of bridges of the multi-bridge circuit; and a controller coupled to the multi-bridge circuit, the first power converter stage, and the second power converter stage, wherein the controller is configured to operate the multi-bridge circuit in a parallel mode in which the second sides of the first and second transformers are switched in parallel to at the DC terminal resulting in a first voltage at the DC terminal being equal to both a second voltage on the side of the first transformer and a third voltage on the side of the second transformer; characterised in that: the controller is further configured to operate the multi-bridge circuit in a series mode in which the second sides of the first and second transformers are switched in series to the DC terminal resulting in a fourth voltage at the DC terminal being a summation of a fifth voltage on the second side of the first transformer and a sixth voltage on the second side of the second transformer.