Patent ID: 8766477

Claim:
A drive system for a facility having an alternating-current isolated network, comprising a three-phase drive machine, operatable both as a motor and as a generator; a converter including a direct-current intermediate circuit including an intermediate circuit voltage, the converter including a network-side current converter and a machine-side current converter, the network-side current converter being connectable on an input side to the alternating-current isolated network and being connected on an output side to the direct-current intermediate circuit, and a motor-side current converter being connected on an input side to the direct-current intermediate circuit and on an output side to the three-phase drive machine, the three-phase drive machine being capable drawing electrical energy from the alternating-current isolated network in motor operation via the converter and being capable of generating electrical energy in generator operation and outputting said electrical energy to the intermediate circuit via the motor-side current converter; and an energy absorbing device arranged in the intermediate circuit and comprising at least one energy absorber which includes at least one ohmic resistor, to absorb at least a part of the electrical energy which the three-phase drive machine generates in generator operation and outputs via the motor-side current converter to the intermediate circuit, the at least one energy absorber being activatable by the energy absorbing device at least as a function of the polarity of the intermediate circuit voltage, wherein, in order to activate the at least one energy absorber, the energy absorbing device includes a diode which is connected in series with the energy absorber and is polarized in such a way that it is conductive with a polarity of the intermediate circuit voltage present during generator operation and blocks with a polarity of the intermediate circuit voltage present during motor operation.