Energy storage circuit with DC chopper superconducting reactor

A two-quadrant converter, which is actively connected to at least one magnetic memory, comprising:

• a) at least a 1st controllable switching element in a 1st d.c. line being actively connected via the at least one magnetic memory to at least a 2nd controllable switching element in a 2nd d.c. line,
• b) the at least one 2nd controllable switching element having a side, actively connected to the at least one magnetic memory, and being connected via a 3rd valve to a side of the 1st switching element which is not actively connected to the at least one magnetic memory,
• c) the at least one 2nd controllable switching element having another side, not actively connected to the at least one magnetic memory and being connected via a 4th valve to another side of the 1st switching element which is actively connected to the at least one magnetic memory, and
• d) the 3rd and 4th valves being semiconductor valves, wherein
• e) a controllable mechanical switching element is connected in parallel to at least one of the two 3rd and 4th valves.

Method of operating a two-quadrant converter which is actively connected to a magnetic memory, comprising the steps of:

• a) actively connecting at least a 1st controllable switching element in a 1st d.c. line via the at least one magnetic memory to at least a 2nd controllable switching element in a 2nd d.c. line,
• b) connecting a side of the at least one 2nd controllable switching element to the at least one magnetic memory and, via a 3rd valve, to a side of the 1st switching element which is not actively connected to the at least one magnetic memory,
• c) connecting another side of the at least one 2nd controllable switching element to the at least one magnetic memory and, via a 4th valve, to another side of the 1st switching element which is actively connected to the at least one magnetic memory, wherein
• d) the 1st or 2nd controllable switching element includes a controllable mechanical switching element.