Rotor, externally excited synchronous machine and motor vehicle

An externally excited synchronous machine, comprising:

• a rotor including:
• a rotor winding;
• a secondary coil;
• and
• a power converter circuit comprising a first secondary coil contact, a second secondary coil contact, a first rotor winding contact, and a second rotor winding contact, the first secondary coil contact and the second secondary coil contact each electrically connected to the secondary coil, the first rotor winding contact and the second rotor winding contact each electrically connected to the rotor winding, the power converter circuit configured, in a first operating mode, to convert an alternating voltage induced in the secondary coil and supplied via secondary coil terminals into a direct voltage and to apply the direct voltage to the rotor winding via rotor winding terminals such that a rotor magnetic field is established and/or maintained,
• wherein the first secondary coil contact and the second secondary coil contact are each connected to the first rotor winding contact via a first line branch of at least one first line branch and to the second rotor winding contact via a second line branch of at least one second line branch,
• wherein each first line branch and each second line branch includes a first switching device and a second switching device, each first switching device and a respective second switching device are connected in series with one another between one secondary coil contact of the first and second secondary coil contacts and one rotor winding contact of the first and second rotor winding contacts,
• wherein each of the first and second switching devices includes a semiconductor switch, each semiconductor switch including an intrinsic diode and/or is connected in parallel to a diode, and
• wherein the intrinsic diode of the first switching device and/or the diode connected in parallel to the first switching device and the intrinsic diode of the second switching device and/or the diode connected in parallel to the second switching device of a respective line branch of the first and second line branches have mutually opposite forward directions;
• a stator on which the rotor is rotatably mounted;
• and
• an energizing device configured to apply an alternating current to a primary coil of the stator, whereby the alternating voltage is induced in the secondary coil of the rotor.

A motor vehicle comprising:

• an externally excited synchronous machine including:
• a rotor including:
• a rotor winding;
• a secondary coil;
• and
• a power converter circuit comprising a first secondary coil contact, a second secondary coil contact, a first rotor winding contact, and a second rotor winding contact, the first secondary coil contact and the second secondary coil contact each electrically connected to the secondary coil, the first rotor winding contact and the second rotor winding contact each electrically connected to the rotor winding, the power converter circuit configured, in a first operating mode, to convert an alternating voltage induced in the secondary coil and supplied via secondary coil terminals into a direct voltage and to apply the direct voltage to the rotor winding via rotor winding terminals such that a rotor magnetic field is established and/or maintained,
• wherein the first secondary coil contact and the second secondary coil contact are each connected to the first rotor winding contact via a first line branch of at least one first line branch and to the second rotor winding contact via a second line branch of at least one second line branch,
• wherein each first line branch and each second line branch includes a first switching device and a second switching device, each first switching device and a respective second switching device are connected in series with one another between one secondary coil contact of the first and second secondary coil contacts and one rotor winding contact of the first and second rotor winding contacts,
• wherein each of the first and second switching devices includes a semiconductor switch, each semiconductor switch including an intrinsic diode and/or is connected in parallel to a diode, and
• wherein the intrinsic diode of the first switching device and/or the diode connected in parallel to the first switching device and the intrinsic diode of the second switching device and/or the diode connected in parallel to the second switching device of a respective line branch of the first and second line branches have mutually opposite forward directions;
• a stator on which the rotor is rotatably mounted;
• and
• an energizing device configured to apply an alternating current to a primary coil of the stator, whereby the alternating voltage is induced in the secondary coil of the rotor.