Method and device for avoiding switching losses in converters

摘要

The invention relates to a method for avoiding switching losses in converters (2) for producing positive and/or negative voltage pulses from a voltage source (5), in that the power supply to a load (18) is cyclically interrupted and/or commutated. The power is fed back to the voltage source via a feedback device during and/or after the interruption of the power supply to the load (18). During the switching operation for the purpose at least of switching out the load (18), the current present at the load (18) is routed in parallel past the switching device (1) and, in so doing, the switching device (1) is essentially dead (deenergised, free from current). Prior to the opening of a main switch (11, 13), preferably a half- or full-bridge or a three-phase bridge, the current flowing through the load (18) is divided between an auxiliary half-bridge (27) and a feedback circuit, whereupon a capacitor (33) of a resonant circuit (32) between the main switches (11, 13) and the auxiliary half-bridge (27) is charged. The capacitor (33) is charged by a current which is greater than or less than the value of the current taken up by the load (18). The main switch (11) of the half-bridge (10) is opened and thereupon the further main switch (13) of the half-bridge (10) is closed, whereupon the capacitor (33) is charged further. After the capacitor (33) has been recharged, a [lacuna] inductively in the resonant circuit (32) or between the latter and the voltage source (5) ... Original abstract incomplete. <IMAGE>