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 (u d l to u dn ) 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 (u v l to u vn ) of compensator voltage (u k ) imprinting the blind current (i k ) and an additional mains-frequency balancing voltage (u b ) having selectable amplitude. The sum of all balancing voltages (u b ) is thus zero and every balancing voltage (u b ) lies in phase or counter-phase to the fundamental oscillation of the blind current (i k ), dependent on whether the measured intermediate circuit voltage (u dl to u dn ) of the multi-quadrant rectifier (2a to 2n) is smaller or larger than a reference value (formula (I)) formed from the intermediate circuit voltages (u dl to u dn ). The invention also relates to a multi-level blind current compensator.