Abstract: A method and apparatus for protecting a high-performance power converter. The high-performance power converter comprises a mains power converter, which converts an alternating voltage from a mains power supply into a direct voltage and supplies the direct voltage to an intermediate direct voltage circuit. The intermediate direct voltage circuit is equipped with an intermediate circuit capacitor, and includes a second power converter which converts the direct voltage from the intermediate direct voltage circuit into an alternating voltage, whereby each of the mains power converter and the second power converter is set up as a bridge circuit and each contains a number of IGBTs (Insulated Gate Bipolar Transistors) arranged in pairs in bridge arms.

Abstract: A low-inductance anode-cathode R-C circuit for a gate-turn-off power thyristor, including circuit diodes, capacitors and line connections for connecting the R-C circuit to a power thyristor. By reducing the spray inductances of circuit diodes, capacitors and line connections of the turn-off unloading circuit of a table-shaped power thyristor (Th), which can be designed for loads of 2500 V and 1000 A, its additional breaking current can be increased and the pulse-peak voltage of the first steep rise of the anode-cathode voltage across the power thyristor, occurring when it is switched off, can be reduced. R-C circuit diodes, capacitors and, preferably, also the power thyristor, have the same axial component direction, that is to say they are arranged axially parallel or coaxially with respect to each other in a low-induction R-C circuit arrangement.

Abstract: A voltage converter provided for use in power electronics, particularly as an inverter for generating alternating voltages for vehicle motors. Electric energy is supplied to the converter via direct-voltage connections (2, 3). The desired alternating voltage can be tapped off at an alternating-voltage connection (1). The alternating-voltage connection (1) is connected via at least one of series connected gate turn-off thyristors (Th1, Th2) and via at least one current limiting reactor (L1), which is connected in series with the gate turn-off thyristors to respective of the positive and negative direct-voltage connection (2, 3). Each gate turn-off thyristor is provided with a turn-off relief circuit (5). In parallel with the current limiting reactor, a reactor free-wheeling diode (D1) is connected in series with a reactor free-wheeling resistor (R1) in a free-wheeling branch.