Patent ID: 8786226

Claim:
A method for operating a drive unit having an electric machine, comprising: operating the electric machine in a normal operating mode with current supplied by an inverter on at least two phases, wherein selected phase voltages for the electric machine are set on the at least two phases, wherein at least two switches including a high-side switch and a low-side switch are allocated to each phase; and wherein in the normal operating mode, a transformation is carried out from rotor-fixed manipulated variables to stator-fixed manipulated variables, and wherein at least one of (i) the stator-fixed manipulated variables include the phase voltages, and (ii) the manipulated variables are limited to a predefined maximum magnitude; and wherein after an occurrence of an error of the inverter, operating the inverter in at least one emergency operating mode for further operation of the electric machine; wherein if the error of the inverter relates to a short-circuit between two phases, a second emergency operating mode is implemented.