A voltage converter for converting a first DC voltage into a second DC voltage and vice versa, the converter including: - first and second DC terminals (16, 18) configured to be electrically connected to a first DC power supply network; - third and fourth DC terminals (20, 22) configured to be electrically connected to a second DC power supply network; - at least one leg extending between the first DC terminal and the second DC terminal, said at least one leg including at least one upper arm and one lower arm electrically connected to each other at a midpoint, each arm comprising a chain of sub-modules including a plurality of sub-modules individually controllable by a control member (T1, T2) specific to each sub-module and each sub-module comprising a capacitor, the control member of each sub-module being able to take at least a first state in which the capacitor is inserted into the chain of sub-modules and a second state in which the capacitor is not inserted into said chain of sub-modules, each chain of sub-modules being able to be modeled by a voltage source able to generate a voltage across it dependent on a number of capacitors placed in series in said chain of sub-modules, each arm comprising an inductance connected in series with the chain of sub-modules of said arm; - a filter module electrically connecting said midpoint of said at least one leg to the third DC terminal, said filter module being configured to limit the circulation of an AC electric current towards said third DC terminal; characterized in that it comprises: - at least one circuit breaker device connected between the midpoint of said at least one leg and the first DC terminal, said circuit breaker device being able to take an open position and a closed position, said circuit breaker device being configured to open when the voltage across the upper arm of said at less than one leg reaches the maximum voltage that can be generated by the chain of sub-modules of said upper arm. - first and second DC terminals (16, 18) configured to be electrically connected to a first DC power supply network; - third and fourth DC terminals (20, 22) configured to be electrically connected to a second DC power supply network; - at least one leg extending between the first DC terminal and the second DC terminal, said at least one leg including at least one upper arm and one lower arm electrically connected to each other at a midpoint, each arm comprising a chain of sub-modules including a plurality of sub-modules individually controllable by a control member (T1, T2) specific to each sub-module and each sub-module comprising a capacitor, the control member of each sub-module being able to take at least a first state in which the capacitor is inserted into the chain of sub-modules and a second state in which the capacitor is not inserted into said chain of sub-modules, each chain of sub-modules being able to be modeled by a voltage source able to generate a voltage across it dependent on a number of capacitors placed in series in said chain of sub-modules, each arm comprising an inductance connected in series with the chain of sub-modules of said arm; - a filter module electrically connecting said midpoint of said at least one leg to the third DC terminal, said filter module being configured to limit the circulation of an AC electric current towards said third DC terminal; - at least one circuit breaker device connected between the midpoint of said at least one leg and the first DC terminal, said circuit breaker device being able to take an open position and a closed position, said circuit breaker device being configured to open when the voltage across the upper arm of said at less than one leg reaches the maximum voltage that can be generated by the chain of sub-modules of said upper arm.