Drive device and method for operating an electrical machine

A drive device for driving an electrical machine having a rotor winding and a stator winding, comprising a regulator connectable to the rotor winding and arranged to drive the rotor winding, the regulator comprising a plurality of switches including a highside switch and a de-energizing switch,

• wherein the highside switch is arranged such that a first terminal of the rotor winding can be connected via the the highside switch to a positive supply terminal of the drive device,
• wherein a semiconductor component is arranged in such a way that the first terminal of the rotor winding can be connected via the semiconductor component to a negative supply terminal of the drive device,
• the de-energizing switch being arranged in such a way that a second terminal of the rotor winding can be connected via the de-energizing switch to the negative supply terminal of the drive device,
• wherein the semiconductor component and the de-excitation switch are arranged and set up such that, when in normal operation the semiconductor component is conductive and the de-excitation switch is opened for de-excitation, a de-excitation circuit is formed via which the rotor winding is de-excited,
• wherein the drive device is arranged to enter a safe state in the presence of at least one fault by disconnecting the rotor winding from the positive supply terminal and/or, with the rotor winding connected, de-energizing the rotor winding,
• the drive device comprising at least one of:
• a) at least one of the plurality of switches of the regulator is designed redundantly,
• b) the regulator has a plurality of measuring points, in particular measuring resistors, which are each provided between the second terminal of the rotor winding and the negative supply terminal of the drive device, and having a plurality of overcurrent measuring devices which are each set up to detect a current in the exciter winding at a respective one of the measuring points and, at least when a predetermined threshold value of the measured current is exceeded, to cause the exciter winding to assume the safe state, or
• c) the drive device comprises a plurality of overvoltage measuring devices, each of which is arranged to measure a voltage and, at least when the measured voltage exceeds a predetermined threshold value, to cause the voltage to enter the safe state.