Patent ID: 8878542

Claim:
A method for dealing with faults in an electrical drive system ( 30 ) having an electrical machine ( 11 ) and a pulse-controlled inverter ( 5 ) which has a first and a second supply connection ( 5 a , 5 b ), said method comprising the steps of: detecting a first fault in the electrical drive system ( 30 ); driving, based on the first fault, the pulse-controlled inverter ( 5 ) to set a circuit state, wherein the circuit state is a free-running mode ( 22 ); if the detected first fault is still present in the electrical drive system ( 30 ) after a predetermined amount of time, driving the pulse-controlled inverter ( 5 ) to set a first short circuit state, selected based on the type of detected first fault, with the short circuit states ( 23 , 24 ) comprising a short circuit ( 23 ) between the power connections ( 10 a , 10 b , 10 c ) of the electrical machine ( 11 ) and the first supply connection ( 5 b ), and a short circuit ( 24 ) between the power connections ( 10 a , 10 b , 10 c ) of the electrical machine ( 11 ) and the second supply connection ( 5 a ); detecting a second fault in the electrical drive system ( 30 ), this second fault occurring in addition to the first fault; selecting a second short circuit state of the short circuit states ( 23 , 24 ) of the pulse-controlled inverter ( 5 ) according to the detected second fault; and driving the pulse-controlled inverter ( 5 ) to change from the first short circuit state to the second short circuit state.