Steuerverfahren zum kreisstromlosen Betrieb von Stromrichtern in Umkehrschaltung

摘要

982,988. Converting; control of D.C. motors. BROWN, BOVERI & CO. Ltd. June 27, 1961 [June 29, 1960], No. 23249/61. Headings H2F and H2J. In an arrangement in which a reversible D.C. motor M is fed by two groups of converting elements S1, S2, in anti-parallel or crossconnection so as to supply current in either sense, and in which each group may act as a rectifier or as an inverter for regenerative braking, the operation to reverse the direction of the motor consists in the following steps to that circulatory currents through the element groups are avoided: (a) Group I (say S1) conductive, Group II (S2) cut-off; (b) grid pulses on Group I delayed for maximum inverter operation, Group II still off; (c) current drops to zero; (d) Group II conducts to supply current in reverse sense Group I remaining cut-off. The mechanism for effecting this operation comprises various comparator circuits and gate circuits utilized with measures of the actual current flow J A ist and the desired current flow J A soll . As shown, grid control units GS1, GS2 for the elements S1, S2 each have three inputs. A first input which is the error signal of J A soll and J A ist derived from a comparator V and amplified at R, shifts the phase of the grid pulses normally. A second input WR1 or WR2 independent of R serves to phase shift the pulses to maximum inverter angle and is applied to that element which should not be conducting as determined by the direction of the desired current J A soll A third input Sp1, Sp2 serves to suppress signals completely and render the vessel S1 or S2 non- conducting. These signals Sp1, Sp2 are derived from an arrangement of monostable triggers Ts, Ti, Tu1 Tu2, two " and " gates U 1 , U 2 , and two " or " gates 01, 02, whose operation is disclosed.