Rotor of an electrical asynchronous machine and method for determining the rotational position of the rotor

An electrical asynchronous machine, comprising:

• a rotor including:
• a rotor shaft which extends along an axis of rotation;
• a rotor laminated core which is directly or indirectly connected to the rotor shaft, wherein the rotor laminated core comprises a plurality of individual sheets which are each oriented perpendicular to the axis of rotation and abut on one another in parallel in a direction of the axis of rotation;
• a plurality of rotor bars which extend in the direction of the axis of rotation and are distributed in a circumferential direction about the axis of rotation, wherein each rotor bar is arranged in a rotor slot which penetrates the rotor laminated core in the direction of the axis of rotation;
• and
• at least one short-circuit ring which connects all rotor bars to one another in an electrically conductive manner,
• wherein the plurality of rotor bars comprises at least three different rotor bars, including at least one first rotor bar having a first width, at least one second rotor bar having a second width and at least one third rotor bar having a third width, wherein each width is defined as the maximum extension of the respective rotor bar in the circumferential direction about the axis of rotation, and wherein the first width, the second width and the third width each differ from one another;
• a stator which has a stator laminated core, wherein the stator laminated core comprises a plurality of individual sheets, which are each oriented perpendicular to the axis of rotation and abut on one another in parallel in the direction of the axis of rotation, and wherein the stator has a plurality of stator windings which are arranged at least in sections in the stator laminated core, wherein the rotor is mounted in the stator so as to be rotatable about the axis of rotation;
• and
• a power electronics which is electrically connected to the stator windings and is configured to apply alternating voltages to the stator windings as required,
• wherein, when alternating voltages are applied to the stator windings by the power electronics, a current flow is established in the rotor bars of the rotor according to an impedance which is distributed asymmetrically in the circumferential direction about the axis of rotation, wherein the impedance of the rotor at a circumferential position about the axis of rotation at which the at least three different rotor bars are arranged differs from the impedance of the rotor at a circumferential position of the axis of rotation where none of the at least three different rotor bars are arranged.

A method for determining a rotational position of a rotor of an electrical asynchronous machine, the electrical asynchronous machine comprising:

• the rotor, the rotor including:
• a rotor shaft which extends along an axis of rotation;
• a rotor laminated core which is directly or indirectly connected to the rotor shaft, wherein the rotor laminated core comprises a plurality of individual sheets which are each oriented perpendicular to the axis of rotation and abut on one another in parallel in a direction of the axis of rotation;
• a plurality of rotor bars which extend in the direction of the axis of rotation and are distributed in a circumferential direction about the axis of rotation, wherein each rotor bar is arranged in a rotor slot which penetrates the rotor laminated core in the direction of the axis of rotation;
• and
• at least one short-circuit ring which connects all rotor bars to one another in an electrically conductive manner,
• wherein the plurality of rotor bars comprises at least three different rotor bars, including at least one first rotor bar having a first width, at least one second rotor bar having a second width and at least one third rotor bar having a third width, wherein each width is defined as the maximum extension of the respective rotor bar in the circumferential direction about the axis of rotation, and wherein the first width, the second width and the third width each differ from one another;
• a stator which has a stator laminated core, wherein the stator laminated core comprises a plurality of individual sheets, which are each oriented perpendicular to the axis of rotation and abut on one another in parallel in the direction of the axis of rotation, and wherein the stator has a plurality of stator windings which are arranged at least in sections in the stator laminated core, wherein the rotor is mounted in the stator so as to be rotatable about the axis of rotation;
• and
• a power electronics which is electrically connected to the stator windings and is configured to apply alternating voltages to the stator windings as required, and
• wherein the method comprises:
• generating a measuring signal by a signal generating unit and transmitting the measuring signal to the stator windings, the measuring signal being formed by a voltage signal,
• transmitting a response signal from the stator windings to a measuring unit, the response signal being formed by a current signal, and
• determining the rotational position of the rotor by the measuring unit from the response signal.