A power converter, comprising: two three-phase AC inputs, connectable to respective three-phase AC sources (301, 302), each three-phase input comprising three rails, each rail configured to receive phase current of the corresponding three-phase AC source; an AC-DC converter circuit (303, 304) arranged for each of the two three-phase AC inputs each AC-DC converter circuit being configured to rectify a received three-phase current into a DC current; the first, second and third rails of the first AC input are connected to respective first, second and third inputs of a first one of the AC-DC converter circuits, and the first, second and third rails of the second AC input are connected to respective first, second and third inputs of the other one of the AC-DC converter circuits; a transformer connected to the rails of the three-phase AC inputs, the transformer having first, second and third primary windings and first, second and third secondary windings; a DC-link, shared between each of the two AC-DC converter circuits; and a load, connected to the DC-link and able to receive DC current therefrom; characterized in that: the transformer is a polygon autotransformer; a first rail (a 1) of a first of the AC inputs is connected to a first rail (a 2) of a second of the AC inputs by the first primary winding of the transformer and to a third rail (c 2) of the second AC input by the second secondary winding of the transformer, a second rail (b 1) of the first AC input is connected to a second rail (b 2) of the second AC input by the second primary winding of the transformer and to the first rail (a 2) of the second AC input by the third secondary winding of the transformer, and a third rail (c 1) of the first AC input is connected to the second rail (b 2) of the second AC input by the first secondary winding of the transformer and to a third rail of the second AC input by the first primary winding of the transformer; and the power converter further comprises a common mode filter, located within the DC-link, and configured to reduce a circulatory current which, when the power converter is in use, flows from the transformer through one of the AC-DC converter circuits, through the DC-link and through a further of the AC-DC converter circuits back to the transformer. two three-phase AC inputs, connectable to respective three-phase AC sources (301, 302), each three-phase input comprising three rails, each rail configured to receive phase current of the corresponding three-phase AC source; an AC-DC converter circuit (303, 304) arranged for each of the two three-phase AC inputs each AC-DC converter circuit being configured to rectify a received three-phase current into a DC current; the first, second and third rails of the first AC input are connected to respective first, second and third inputs of a first one of the AC-DC converter circuits, and the first, second and third rails of the second AC input are connected to respective first, second and third inputs of the other one of the AC-DC converter circuits; a transformer connected to the rails of the three-phase AC inputs, the transformer having first, second and third primary windings and first, second and third secondary windings; a DC-link, shared between each of the two AC-DC converter circuits; and a load, connected to the DC-link and able to receive DC current therefrom; characterized in that: the transformer is a polygon autotransformer; a first rail (a 1) of a first of the AC inputs is connected to a first rail (a 2) of a second of the AC inputs by the first primary winding of the transformer and to a third rail (c 2) of the second AC input by the second secondary winding of the transformer, a second rail (b 1) of the first AC input is connected to a second rail (b 2) of the second AC input by the second primary winding of the transformer and to the first rail (a 2) of the second AC input by the third secondary winding of the transformer, and a third rail (c 1) of the first AC input is connected to the second rail (b 2) of the second AC input by the first secondary winding of the transformer and to a third rail of the second AC input by the first primary winding of the transformer; and the power converter further comprises a common mode filter, located within the DC-link, and configured to reduce a circulatory current which, when the power converter is in use, flows from the transformer through one of the AC-DC converter circuits, through the DC-link and through a further of the AC-DC converter circuits back to the transformer. the transformer is a polygon autotransformer; a first rail (a 1) of a first of the AC inputs is connected to a first rail (a 2) of a second of the AC inputs by the first primary winding of the transformer and to a third rail (c 2) of the second AC input by the second secondary winding of the transformer, a second rail (b 1) of the first AC input is connected to a second rail (b 2) of the second AC input by the second primary winding of the transformer and to the first rail (a 2) of the second AC input by the third secondary winding of the transformer, and a third rail (c 1) of the first AC input is connected to the second rail (b 2) of the second AC input by the first secondary winding of the transformer and to a third rail of the second AC input by the first primary winding of the transformer; and the power converter further comprises a common mode filter, located within the DC-link, and configured to reduce a circulatory current which, when the power converter is in use, flows from the transformer through one of the AC-DC converter circuits, through the DC-link and through a further of the AC-DC converter circuits back to the transformer.