Method for operation of a converter circuit, and apparatus for carrying out the method

An apparatus for operation of a converter circuit having a first and second partial converter systems, the partial converter systems being connected in series to one another via two series-connected inductances, a junction point between the two series-connected inductances forming an output connection, each partial converter system having at least one two-pole switching cell, and each switching cell having two series-connected controllable bidirectional power semiconductor switches with a controlled unidirectional current flow direction, and a capacitive energy store connected in parallel with a series circuit formed by the power semiconductor switches, the apparatus comprising:

• a first control circuit for producing a first control signal for power semiconductor switches in switching cells of a first partial converter system, based on an input received as a voltage oscillation signal across two series-connected inductances and on a first switching function for the power semiconductor switches in switching cells of the first partial converter system;
• a second control circuit for producing a second control signal for power semiconductor switches in switching cells of the second partial converter system based on an input received as the voltage oscillation signal across the two series-connected inductances and on a second switching function for the power semiconductor switches in switching cells of the second partial converter system;
• and
• a first calculation unit for producing the first and second switching functions from a voltage oscillation signal with respect to an input representing a voltage at the output connection and a reference signal.