A DC-DC converter (200; 500; 610, 620; 700) for high voltage direct current (HVDC) power transmission and distribution and for converting a first DC voltage into a second DC voltage or vice versa and comprising: a first phase leg (710, 720) having a first, a second, and a third connection terminal, the first phase leg comprising: a first (201; 501; 611, 621; 721) and a second (202; 502; 612, 622; 722) variable voltage source being arranged for providing a first ( U 1 ( t)) and a second voltage ( U 2 ( t)), respectively, each voltage having an AC voltage component and a DC voltage component, each voltage source having a first pole and a second pole, the first pole of the first voltage source being connected to the first terminal of the phase leg, the second pole of the first voltage source being connected to the first pole of the second voltage source, and the second pole of the second voltage source being connected to the second terminal of the phase leg, wherein the first DC voltage ( U DC1) is provided between the first terminal and the second terminal of the phase leg, and the second DC voltage ( U DC2) is provided between the third terminal and the second terminal of the phase leg, and an alternating current, AC, filter (204; 504; 614, 624; 724) being connected between the first pole of the second voltage source and third terminal of the phase leg, characterized by a first capacitor (203; 503; 613, 623; 723) being connected between the first terminal and the second terminal of the phase leg, and controlling means being arranged for controlling the first and the second voltage source of the first phase leg so as to circulate an AC current ( I AC ( t)) within a circuit comprising the first capacitor, the first voltage source, and the second voltage source, of the first phase leg, to thereby exchange, in use, power between said first and second variable voltage source. a first phase leg (710, 720) having a first, a second, and a third connection terminal, the first phase leg comprising: a first (201; 501; 611, 621; 721) and a second (202; 502; 612, 622; 722) variable voltage source being arranged for providing a first ( U 1 ( t)) and a second voltage ( U 2 ( t)), respectively, each voltage having an AC voltage component and a DC voltage component, each voltage source having a first pole and a second pole, the first pole of the first voltage source being connected to the first terminal of the phase leg, the second pole of the first voltage source being connected to the first pole of the second voltage source, and the second pole of the second voltage source being connected to the second terminal of the phase leg, wherein the first DC voltage ( U DC1) is provided between the first terminal and the second terminal of the phase leg, and the second DC voltage ( U DC2) is provided between the third terminal and the second terminal of the phase leg, and an alternating current, AC, filter (204; 504; 614, 624; 724) being connected between the first pole of the second voltage source and third terminal of the phase leg, a first (201; 501; 611, 621; 721) and a second (202; 502; 612, 622; 722) variable voltage source being arranged for providing a first ( U 1 ( t)) and a second voltage ( U 2 ( t)), respectively, each voltage having an AC voltage component and a DC voltage component, each voltage source having a first pole and a second pole, the first pole of the first voltage source being connected to the first terminal of the phase leg, the second pole of the first voltage source being connected to the first pole of the second voltage source, and the second pole of the second voltage source being connected to the second terminal of the phase leg, wherein the first DC voltage ( U DC1) is provided between the first terminal and the second terminal of the phase leg, and the second DC voltage ( U DC2) is provided between the third terminal and the second terminal of the phase leg, and an alternating current, AC, filter (204; 504; 614, 624; 724) being connected between the first pole of the second voltage source and third terminal of the phase leg, characterized by a first capacitor (203; 503; 613, 623; 723) being connected between the first terminal and the second terminal of the phase leg, and controlling means being arranged for controlling the first and the second voltage source of the first phase leg so as to circulate an AC current ( I AC ( t)) within a circuit comprising the first capacitor, the first voltage source, and the second voltage source, of the first phase leg, to thereby exchange, in use, power between said first and second variable voltage source. a first capacitor (203; 503; 613, 623; 723) being connected between the first terminal and the second terminal of the phase leg, and controlling means being arranged for controlling the first and the second voltage source of the first phase leg so as to circulate an AC current ( I AC ( t)) within a circuit comprising the first capacitor, the first voltage source, and the second voltage source, of the first phase leg, to thereby exchange, in use, power between said first and second variable voltage source.