Circuit for converter (inverter), especially pulse-controlled inverter

摘要

The invention relates to an additional circuit for converters, especially pulse-controlled inverters, having pairs of branches, in which a freewheel diode connected in antiparallel and an RCD network, controlled by an auxiliary switch and acting as a low-loss load-rejecting circuit, are assigned to each branch switch. In order not to detrimentally affect the functioning of the low-loss load-rejecting circuit, it is proposed according to the invention that one clamping circuit (K) having a high-capacitance additional capacitor (CK) be provided per branch pair as an additional RC circuit. The additional capacitor (CK) is connected in parallel with the D.C. source (6) and furthermore has its terminals crossed over via blocking diodes (DK1 and DK2) to the central divider points (11, 12) of the two controlled RCD networks. Effective voltage limitation for the semiconductor branch switches is thereby achieved in the case of pulse-controlled inverter circuits affected by induction. Semiconductor switches having low reverse values can be used, which are less expensive and smaller and cause less power loss. <IMAGE>