SYMMETRIERUNGSEINRICHTUNG FÜR EIN VON EINEM UNSYMMETRISCHEN VERBRAUCHER BELASTETES DREHNETZ

摘要

To balance the unbalanced consumer (4), a self-commutated power converter (5) is connected on the AC voltage side (u, v, w) with transposed phase sequence to the three-phase voltage mains. Its valves (A to F) are automatically resettable and are controlled in such a way that an output current (i1, i2, i3) with a mains-frequency fundamental oscillation is generated whose phase angle and amplitude are controlled in relation to the AC mains voltage (R, S, T) according to the phase angle or amplitude of a negative phase-sequence power system required for balancing. In order to achieve high adjustment speeds at acceptable cost when balancing unbalance changes without the device consuming excessively high reactive currents, a constant direct current (Id) corresponding to the maximum unbalance power which is to be balanced is fed into the power converter (5) from a DC source (10) and the terminals (7, 8) of the power converter (5) on the DC side are interconnected by means of a DC controller (18) disposed in parallel with the power converter valves (A to F) which is controlled with a clock frequency (fg) which is an integral multiple of the mains frequency (fn) of the AC mains voltage. <IMAGE>