METHOD FOR BALANCING THE INTERMEDIATE CIRCUIT VOLTAGES IN A SELF-GUIDED, MULTI-LEVEL BLIND CURRENT COMPENSATOR AND SELF-GUIDED, MULTI-LEVEL BLIND CURRENT COMPENSATOR

摘要

The invention relates to a method for balancing the intermediate circuit voltages (udl to udn) in a self-guided, multi-level blind current compensator (1) with a plurality of multi-quadrant rectifiers (2a to 2n) connected in series, wherein each multi-quadrant rectifier (2a to 2n) applies a pulse width modulated voltage that is made up of an equal portion (uvl to uvn) of compensator voltage (uk) imprinting the blind current (ik) and an additional mains-frequency balancing voltage (ub) having selectable amplitude. The sum of all balancing voltages (ub) is thus zero and every balancing voltage (ub) lies in phase or counter-phase to the fundamental oscillation of the blind current (ik), dependent on whether the measured intermediate circuit voltage (udl to udn) of the multi-quadrant rectifier (2a to 2n) is smaller or larger than a reference value (formula (I)) formed from the intermediate circuit voltages (udl to udn). The invention also relates to a multi-level blind current compensator.