Method and apparatus for detecting a short circuit of a semiconductor switching element in an inverter for energizing an electric drive in an electric or hybrid vehicle; inverter having such a device

The invention relates to a method for detecting a short circuit of semiconductor switching elements in an inverter which is designed to operate an electric drive in an electric or hybrid vehicle and which comprises a plurality of semiconductor switching elements, the semiconductor switching elements forming a high side and a low side, the high side and the low side each comprise one or more semiconductor switching elements connected in parallel, the high side and the low side being connected in parallel with an intermediate loop capacitor of the inverter, the method comprising the following steps (101-106): measuring an intermediate loop voltage occurring at the intermediate loop capacitor; determining an intermediate loop capacitance of the intermediate loop capacitor; determining the short-circuit resistance of the inverter; specifying a time constant from the intermediate loop capacitance and the short-circuit resistance, preferably by multiplying the intermediate loop capacitance by the short-circuit resi