Method for controlling an electrical machine, and control system

Abstract

The invention relates to a method for controlling a multi-phase electrical machine (2) comprising a stator (20) and a rotor (21), comprising the steps: identifying (S1) a short-circuit (K) in a turn of a winding (201) of the electrical machine (2) and at least one parameter describing the short-circuit (K) in the turn; setting (S2) an angle (η) of a current vector to the positive q-axis in the dq coordinate system of the rotor (21), having a negative d portion and a q portion which does not equal zero, on the basis of the at least one parameter describing the short-circuit (K) in the turn; and controlling (S3) the electrical machine (2) according to the set angle (η).

Description

[0001] Method for controlling an electrical machine and control system

[0002] Description

[0003] The present disclosure relates in particular to a method for controlling an electrical machine, to a control system, to an electrical machine with such a control system and to a computer-readable storage medium.

[0004] Vehicles, especially aircraft, are powered in a wide variety of ways. Internal combustion engines, such as piston engines or gas turbine engines, enable long ranges and high speeds. Drives with one or more electric motors, on the other hand, enable the use of sustainably generated energy and are sometimes particularly low-maintenance and quiet. Advances in battery and fuel cell technology are opening up ever-expanding areas of application for electric drives.

[0005] In an electric motor of an electric drive, windings can be wound around the teeth of a stator, for example. By applying a three-phase alternating voltage to the windings, magnetic fields are built up which cause a permanent magnet rotor, for example, to move relative to the stator. If a short circuit occurs between adjacent turns of one of the windings due to aging processes, vibrations or external influences, the magnetic fields of the rotating rotor can induce very large electrical currents in the short-circuited winding loop as a result of the rotation of the rotor. These currents can lead to strong local heating and, in the worst case, to thermal destruction of the electric motor. This is particularly relevant, not only but in particular, for aircraft which, for example, use permanent magnet induction motors.Therefore, electric motors are typically designed to withstand several times the thermal load encountered during normal operation, until the rotor comes to a standstill, e.g., by adjusting the rotor blades and / or applying a brake. However, such measures, in turn, result in increased weight and a complex structure, thus increasing energy consumption and reducing range. Furthermore, the failure of one electric motor usually results in a loss of a large portion of the drive power, so a larger number of electric motors is usually provided, e.g., 4, 6, or 8 electric motors.

[0006] In "Detection and Compensation of Interturn Short Circuit in Interior Permanent Magnet Synchronous Machines Under Two-Level Voltage Source Inverter Limitations," IEEE Transactions on Industry Applications, Vol. 58, No. 6, November / December 2022, PC Palavicino describes various aspects of the problem described and the setting of a d-axis current to compensate for the magnetic flux resulting from rotor rotation. However, the solution described therein has only limited practical application.

[0007] The object of the present invention is to improve the reliability of an electrical machine.

[0008] According to one aspect, a method for controlling a multi-phase (e.g., three-phase) electrical machine having a stator and a rotor is provided. The method comprises: detecting a turn-to-turn short circuit of a winding of the electrical machine and at least one parameter describing the turn-to-turn short circuit; setting an angle of the current vector (relative to the positive q-axis) in the dq coordinate system of the rotor with a negative d-component and a non-zero q-component based on the at least one parameter describing the turn-to-turn short circuit; and controlling the electrical machine according to the set angle of the current vector (relative to the positive q-axis).

[0009] By dynamically adjusting the angle of the current vector to the positive q-axis, and thus the ratio of the d and q components in the rotor's dq coordinate system, to the occurring error, it is possible to minimize the remaining currents through the short-circuited conductor loop. This can reduce the thermal load even in the event of a short circuit. As a result, the electrical machine, such as an electric motor, can be designed particularly simply and with a reduced overall weight.

[0010] As is well known, a multi-phase system is described by a number of n coordinates. For example, a three-phase system is described by three coordinates U, V and W, each offset by an angle of 120°. The currents flowing through the windings corresponding to these n (e.g. three) coordinates in a symmetrical multi-phase system (e.g. three-phase system) add up to 0. Using a dq transformation, the dq coordinate system rotates with the rotor, with axes d and q at right angles to one another. In this way, it is possible to describe the rotating field at a constant speed using the two time-constant quantities d and q. The value d represents the magnetic flux density of the magnetic excitation in the rotor. The value q describes the torque generated by the rotor. Changes over time (e.g. in speed and / or torque) result in changes over time in the d component and / or the q component.An advantage of the dq transformation is that rotating field machines can be controlled with a PI controller.

[0011] By adjusting the angle of the current vector to the positive q-axis with a negative d-component, the magnetic flux generated by the rotor excitation is compensated. By setting a non-zero q-component, torque can still be generated despite the short circuit.

[0012] Optionally, the angle of the current vector to the positive q-axis can be set within a predetermined angular range, e.g., within the range of 30° to 85°, particularly within the range of 40° to 80°. It has been shown that, depending on the application, the greatest reduction in the current in the short-circuited conductor loop is possible in certain, pre-determined ranges, e.g., within the ranges mentioned, in most cases of interturn short circuits. For example, a negative, non-zero q-component can be specified.

[0013] The electrical machine may comprise several (e.g., 2, 3, or 4) electrically isolated winding systems (which may also be referred to as lanes). Each of the winding systems may have windings for n (e.g., three) electrical phases. When the interturn short circuit is detected, it is possible to detect in which of the winding systems the interturn short circuit has occurred. It may be provided that, when controlling the electrical machine, (in particular, only) the winding system with the interturn short circuit is controlled according to the set angle. This allows the remaining winding systems to continue operating at full or nearly full power.

[0014] The angle of the current vector to the positive q-axis is optionally adjusted based on the electrical currents (and thus magnetic fields) of the winding systems in which the interturn short circuit did not occur. Since the individual winding systems influence each other, the currents in the other winding systems can also induce currents in the shorted conductor loop, and vice versa. For example, the defective winding can be energized in such a way that the induction by the other winding systems is at least partially compensated.

[0015] The at least one parameter describing the interturn short circuit can comprise a characteristic, e.g., a location of the interturn short circuit within a winding, for example, in the form of an identification, e.g., a number, of a turn. For each possible location of an interturn short circuit, a corresponding angle of the current vector to the positive q-axis (or a dependence of the angle on one or more other parameters) can be stored. This is based on the realization that the optimal angle of the current vector to the positive q-axis can vary greatly for different locations. Thus, an individually optimized angle can be set for each possible location of the interturn short circuit.

[0016] Optionally, the characteristic, e.g., the location of the interturn short circuit, is determined using at least one sensor, e.g., one or more Hall sensors, one or more coils, or the like. Furthermore, operating parameters of an inverter supplying current to the winding can be evaluated.

[0017] The angle of the current vector to the positive q-axis can be adjusted using a look-up table. This allows for simple and particularly fast response.

[0018] The at least one parameter describing the interturn short circuit can include a residual resistance of the interturn short circuit. Depending on whether the short circuit has a resistance of almost 0 or, for example, 10 mΩ, the optimal angle of the current vector to the positive q-axis can vary considerably.

[0019] For example, in the step of adjusting the angle of the current vector to the positive q-axis, a smaller angle is set for a larger residual resistance than for a smaller residual resistance. This allows particularly suitable angles to be determined.

[0020] Optionally, the residual resistance of the interturn short circuit is determined, e.g., measured, using at least one sensor. For example, voltages are measured at several points. A change in the voltage drop resulting from an interturn short circuit can be used, for example, to determine the residual resistance using a current known from the inverter.

[0021] According to one aspect, a method is provided for controlling a multi-phase, e.g., three-phase, electrical machine having a stator and a rotor, in particular for flux compensation in the event of a turn-to-turn short circuit. The method can be carried out according to any embodiment described above. The method comprises detecting a turn-to-turn short circuit of a winding of the electrical machine and at least one parameter describing the turn-to-turn short circuit; setting a negative d-component and / or a non-zero q-component in the dq coordinate system of the rotor based on the at least one parameter describing the turn-to-turn short circuit; and controlling the electrical machine according to the set d- and q-components in the dq coordinate system. With regard to the advantages, reference is made to the above information.

[0022] According to one aspect, a control system for controlling a multi-phase, e.g. three-phase, electrical machine having a stator and a rotor is provided, wherein the control system is configured to carry out the method according to any aspect described herein in any configuration described herein.

[0023] According to one aspect, an electric machine is provided. The electric machine comprises the control system according to any embodiment described herein. The electric machine further comprises a stator and a rotor rotatable relative to the stator. The stator is arranged, for example, in a rotationally fixed manner with respect to a bearing supporting the electric machine.

[0024] The electrical machine may comprise a plurality of electrically separated winding systems, each of the winding systems having windings for n, e.g. three, electrical phases.

[0025] According to one aspect, a vehicle, in particular an aircraft, is provided, comprising the electric machine according to any embodiment described herein, in particular for driving a thrust-generating device, e.g., a propeller. The vehicle, in particular an aircraft, comprises, for example, a rotor unit drivable by the electric machine. The advantages of the electric machine described herein and its control system are particularly evident in a vehicle, in particular in an aircraft.

[0026] According to one aspect, a computer-readable storage medium is provided, comprising instructions that, when executed by a processor arrangement (e.g., of the control system), cause the processor arrangement (and / or the control system) to perform the method according to any aspect described herein in any configuration described herein.

[0027] Embodiments will now be described by way of example with reference to the figures, in which:

[0028] Figure 1 an aircraft in the form of an airplane with an electric

[0029] engine and a propeller driven by it;

[0030] Figure 2 is a schematic sectional view of a basic

[0031] Construction of a permanent magnet, multi-phase, here exemplified three-phase electrical machine as an internal rotor;

[0032] Figure 3 is a dq diagram showing an example angle of the

[0033] current vector to the positive q-axis with a q-component other than zero;

[0034] Figure 4 is a schematic sectional view of a tooth of a stator of the electrical machine according to Figure 2 with a winding short circuit between two adjacent windings;

[0035] Figures 5 to 7 are diagrams in which relative current intensities are plotted as a function of a set angle of the current vector to the positive q-axis in the case of the winding short circuit according to Figure 4;

[0036] Figure 8 is a schematic sectional view of a tooth of a stator of the electrical machine according to Figure 2 with a winding short circuit between two other adjacent windings than in Figure 4;

[0037] Figures 9 to 11 are diagrams in which relative current intensities are plotted as a function of a set angle of the current vector to the positive q-axis in the case of the winding short circuit according to Figure 8; and

[0038] Figure 12 shows a method for controlling a multi-phase, here exemplary three-phase electrical machine.

[0039] Figure 1 shows an aircraft 3 in the form of an electrically powered airplane. The aircraft 3 comprises a rotor unit 30, here in the form of a propeller, with several rotor blades 300, which is driven by an electric motor 2. The exemplary aircraft 3 comprises a fuselage 31 and wings 32.

[0040] The aircraft 3 further comprises an energy source, here in the form of an electric battery system 33. Alternatively or additionally, the aircraft 3 can comprise a fuel cell and / or a generator. The electric machine 2 is supplied with energy by the energy source, wherein the energy source is electrically connected to an inverter system 22, which in turn supplies the electrical energy to the electric machine.

[0041] Furthermore, the electric machine of the aircraft 3 comprises a control system 1 which controls the inverter system 22 and thus the electric machine 2.

[0042] Figure 2 shows a schematic sectional view of the rotating electric machine 2 of the aircraft 3, which here is designed as a permanent magnet synchronous machine. Figure 2 shows that the electric machine 2 is designed as an internal rotor. The electric machine 2 comprises a stator 20, which has an opening (not designated), in particular a through-opening, in which a rotor 21 is rotatably mounted.

[0043] The stator 20 comprises a body, here in the form of a laminated core, to which teeth 203 are fixed, which can also be referred to as stator teeth. The teeth 203 are aligned with an air gap L between the body 10 of the stator 21 and the rotor 21. The teeth 203 protrude radially from the body, in this case radially inward.

[0044] The stator 20 has several winding systems 200A-200D. The winding systems 200A-200D are electrically separated from each other. Each of the winding systems 200A-200D has windings 201 for three electrical phases U, V, and W. The individual winding systems 200A-200D are only shown schematically here for simplified representation. Electrical conductors of the winding systems 200A-200D are wound around the teeth 203 of the stator 20 in the form of windings 201.

[0045] Each of the winding systems 200A-200D is designed for three-phase operation, i.e., it is connected to a three-phase alternating voltage with phases U, V, and W. During normal operation of the electrical machine 2, the winding systems 200A-200D are accordingly supplied with the alternating voltage.

[0046] In this case, the rotor 21 is designed, for example, as a salient-pole rotor, which includes permanent magnets to provide the magnetic flux. In the present embodiment, the rotor 21 has precisely one magnetic north pole N and one magnetic south pole S. In alternative embodiments, more magnetic poles can also be provided alternating in the circumferential direction transverse to a rotational axis of the rotor 21 (relative to the stator 20).

[0047] The rotor 21 is rotatably mounted. During normal operation, the three-phase alternating voltage, whose phases U, V, and W are each phase-shifted by 120°, generates a rotating magnetic field that interacts with the permanently excited magnetic field provided by the rotor 21, so that, during motor operation, a corresponding rotational movement of the rotor 21 relative to the stator 20 can be induced. In the present case, the electric machine 2 serves as the drive motor for the rotor unit 30 of the aircraft 3. Figure 2 schematically shows the sections of the winding systems 200A-200D assigned to the respective phases U, V, and W.

[0048] Each of the winding systems 200A-200D of the electrical machine 2 is connected to a three-phase inverter 220 of the inverter system 22. The respective inverter 220 provides the electrical alternating voltage with the three phases U, V, W for the corresponding winding system 200A-200D. The inverters 220 draw the electrical energy required for proper operation from the energy source connected to the inverter system 22, here in the form of the battery system 33. Each of the inverters 220 has assigned inverter units for providing the phases U, V, W. Each inverter unit has a half-bridge circuit. The respective half-bridge circuit has a series connection of two electronic switching elements (e.g., transistors) that are connected to an intermediate circuit DC voltage of the inverter 220.The electronic switching elements are operated in a clock mode, which, for example, provides clock patterns similar to a PWM signal. The corresponding phases U, V, and W of the three-phase alternating voltage are then available at a respective center tap of the half-bridge circuits. The inductance of the windings 201 provides appropriate filtering, so that a corresponding alternating current is generated for each of the phases U, V, and W, which, with appropriate control of the inverter units, can be nearly sinusoidal.

[0049] The individual 220 inverters are independent of each other. If one of the 200A-200D winding systems or one of the 220 inverters fails, the other 200A-200D inverters and 200A-200D winding systems can continue to operate.

[0050] The control system 1 is communicatively connected to the inverter system 22. The control system 1 controls the inverters 220 of the inverter system 22. In this case, the control is carried out using the rotor-fixed dq coordinate system.

[0051] In the event of an interturn short circuit, in which adjacent turns within a winding 201 are short-circuited to one another, e.g., due to defective insulation, a very large current can be induced in the short-circuited conductor loop by the rotor 21, which continues to rotate (at least for a certain period of time), even when the current supply to the affected winding system 200A-200D is switched off. This could lead to high thermal stress and thus to consequential damage. To compensate for the magnetic flux caused by the rotor 21, the control system 1 is configured to detect an interturn short circuit in a winding 201 of the electrical machine 2. Furthermore, the control system 1 is configured to detect at least one parameter describing the interturn short circuit.Furthermore, the control system 1 is configured to set a negative d-component and / or a q-component non-zero in the dq coordinate system of the rotor 21 based on the at least one parameter describing the inter-turn short circuit in response to the detection of the inter-turn short circuit. In particular, the control system of the described example is configured to set an angle q of the current vector to the positive q-axis in the dq coordinate system of the rotor 21 with a negative d-component and a q-component non-zero based on the at least one parameter describing the inter-turn short circuit. Furthermore, the control system 1 is configured to control the electric machine 2, in particular by controlling the inverters 220, according to the set angle q.

[0052] In this way, the magnetic flux caused by the rotating rotor 21 can be compensated so that only a significantly lower current flows in the short-circuited conductor loop.

[0053] The control system comprises a processor arrangement 11 and a storage medium 10 on which instructions are stored which, when executed by the processor arrangement 11, cause the processor arrangement 11 and the control system 1 to carry out a corresponding method.

[0054] Figure 3 illustrates the dq coordinate system. It shows a current vector I, which has both a positive q-component, non-zero, and a negative d-component, non-zero. The magnitude of these two components determines the angle q, which corresponds to the angle of the current vector I to the positive q-axis. The precise adjustment of this angle q of the current vector to the positive q-axis for controlling the inverter 220 allows for particularly effective flux compensation, as will be explained in more detail below.

[0055] Figure 4 shows a section of the stator 20 with one of the teeth 203. A winding 201 is wound around the tooth 203. The winding 201 here, for example, comprises only one conductor from one of the winding systems 200A-200D, specifically from one phase, but can alternatively also comprise conductors from several of the winding systems 200A-200D. The winding 201 comprises a plurality of turns, including several intact turns 202A. However, between two further turns 202B, 202C, there is a turn-to-turn short circuit K. Due to the turn-to-turn short circuit K, the turns 202B, 202C are short-circuited to one another. This creates a closed loop of the conductor forming the turns 202B, 202C.

[0056] In the example of Figure 4, the winding short circuit K is formed adjacent to an end of the tooth 203 facing the rotor 21.

[0057] Figure 5 shows the current IITSC induced in the short-circuited conductor loop as a result of the rotation of the rotor 21 (normalized to the nominal current of the winding Inom during normal operation of the electric machine 2) versus the angle q of the current vector to the positive q-axis from 0 to 90 degrees. The abbreviation ITSC stands for "Inter-Turn Short Circuit." Figure 5 shows four different curves, of which the two upper ones are shown separately in Figure 6 for improved clarity, and the two lower ones are also shown separately in Figure 7. All four curves are the result of simulations and illustrate the dependence of the optimal angle q on a parameter describing the interturn short circuit K, namely the residual resistance of the interturn short circuit K.

[0058] The two curves shown at the top in Figure 5 and separately in Figure 6 correspond to a perfect interturn short circuit K at the location illustrated in Figure 4, which has a residual resistance of 0 0. The two lower curves shown separately in Figure 7 correspond to a interturn short circuit K at the location illustrated in Figure 4, which has a residual resistance of 10 mO.

[0059] It is clear that a lower residual resistance leads, as expected, to a larger induced current IITSC. However, what is remarkable is the strong dependence of the induced currents IITSC on the angle q of the current vector to the positive q-axis. All of the curves exhibit a minimum at which the induced current IITSC is at a minimum at a corresponding angle q. This angle q, corresponding to the minimum induced current IITSC, can be referred to as the optimal angle q of the current vector to the positive q-axis because it allows the best reduction of the current in the short-circuited conductor loop. For the two upper curves in Figure 5 (better visible in Figure 6), the optimal angle q is in the range of 80°. In contrast, the optimal angle q for the two lower curves in Figure 5 (better visible in Figure 7) is between 40° and 50°.Therefore, the control system 1 is designed to set a smaller angle q for a larger residual resistance than for a smaller residual resistance.

[0060] The top curve in Figure 5, at 50°, corresponds to a current intensity Imitigation through winding 203 with the interturn short circuit K, used to compensate for the rotor flux, with a magnitude equal to the nominal current. A greater reduction in the current in the short-circuited conductor loop allows for a larger current intensity, as illustrated by the second curve from the top, at 50°. This corresponds to a current intensity Imitigation through winding 203 with the interturn short circuit K, used to compensate for the rotor flux, with a magnitude twice the nominal current.The two lower curves in Figure 5 also correspond to a current intensity Imitigation used to compensate the rotor flux through the winding 203 with the turn-to-turn short-circuit K with an amount equal to the nominal current (top) and a current intensity Imitigation used to compensate the rotor flux through the winding 203 with the turn-to-turn short-circuit K with an amount of twice the nominal current (bottom).

[0061] Thus, by measuring the residual resistance by the control system 1, e.g. by means of at least one sensor 12A, 12B (see Figure 2, e.g. in the manner already described) and / or based on operating data of the corresponding inverter 220, the optimal angle q of the current vector to the positive q-axis can be determined and set based on the known dependence thereon.

[0062] Alternatively or additionally, the current intensity imitation that can be used to compensate the rotor flux can also be used to determine the optimal angle q of the current vector to the positive part of the q-axis. Figures 5 to 7 show four different possible cases merely as examples. The control system 1 can store considerably more values ​​for possible residual resistances and / or usable current intensities. Optionally, the control system 1 comprises a look-up table in which the control system 1 specifies an optimal angle q for each set of values ​​(e.g. residual resistance, usable current intensity and / or location). Optionally, the control system 1 can interpolate between the respective angle q if the current value lies between two values.

[0063] Figure 8 shows the section of the stator 20 corresponding to Figure 4, although here the interturn short circuit K has occurred at a different location, namely between a turn 202D and a turn 202E. The turns 202D and 202E are arranged adjacent to an end of the tooth 203 facing away from the rotor 21. Figures 9 to 11 again correspond to Figures 5 to 7, but were calculated for the location shown in Figure 8. Comparing Figures 5 to 7 with Figures 9 to 11 reveals significant differences in the minima of the curves and thus the respective optimal angles q. These are located at larger values ​​of the angle q.

[0064] The at least one parameter describing the interturn short circuit K thus also includes the location of the interturn short circuit K within the winding 201. The location of the interturn short circuit K is determined, for example, by means of at least one sensor 12A, 12B (see Figure 2, e.g., in the manner already described) and / or based on operating data of the corresponding inverter 220. Once the location has been determined, the control system 1 can determine and set the optimal angle q for this location (and optionally the measured residual resistance and / or the determined current intensity Imitigation that can be used to compensate for the rotor flux). The angle q is set, for example, in the range from 30° to 85°, in particular in the range from 40° to 80°. The aforementioned look-up table can also include the location. Alternatively or additionally, the control system 1 can include a machine learning model.This can be trained with training data according to Figures 5-7 and 9-11 and thus output the optimal angle q for input measured values ​​(e.g., with respect to residual resistance and / or location). Furthermore, a stator flux can also be measured and minimized by control system 1.

[0065] This allows for the determination and adjustment of an angle q of the current vector to the positive q-axis that is specifically optimized for the fault encountered. Optionally, the angle q can be dynamically adjusted, particularly during flux compensation, and continuously updated, as the residual resistance, for example, can change over time.

[0066] When detecting the interturn short circuit K, the control system 1 further detects in which of the winding systems 200A-200D the interturn short circuit K occurred. When controlling the electric machine 2, the winding system 200A-200D with the interturn short circuit K is controlled according to the set angle q. Optionally, the angle q is set based on the electrical currents of the winding systems 200A-200D in which the interturn short circuit K did not occur.

[0067] Figure 12 shows a method for controlling a three-phase electrical machine 2 with a stator 20 and a rotor 21, namely for compensating a current induced in the event of a winding short circuit. The method comprises the following steps:

[0068] Step S1: Detecting a winding short circuit K of a winding 201 of the electrical machine 2 and at least one parameter describing the winding short circuit K.

[0069] Step S2: Setting an angle q of the current vector to the positive q-axis in the dq coordinate system of the rotor 21 with a negative d-component and a q-component other than zero based on the at least one parameter describing the winding short circuit K, and / or setting S2 a negative d-component and / or a q-component other than zero in the dq coordinate system of the rotor 21 based on the at least one parameter describing the winding short circuit K.

[0070] Step S3: Controlling the electric machine 2 according to the set angle q (and / or according to the set d-component and / or the set q-component in the dq coordinate system).

[0071] The described field-oriented control thus allows a particularly effective compensation of the induced current in the event of a fault and thus an increased reliability.

[0072] It should be understood that the invention is not limited to the embodiments described above, and various modifications and improvements may be made without departing from the concepts described herein. Any of the features may be used separately or in combination with any other features, provided they are not mutually exclusive, and the disclosure extends to and encompasses all combinations and subcombinations of one or more of the features described herein.

[0073] List of reference symbols

[0074] 1 control system

[0075] 10 Storage medium

[0076] 11 Processor arrangement

[0077] 12A, 12B Sensor

[0078] 2 electric machine

[0079] 20 Stator

[0080] 200A-200D winding system

[0081] 201 Winding

[0082] 202A-202E winding

[0083] 203 tooth

[0084] 21 Rotor

[0085] 22 Inverter system

[0086] 220 inverters

[0087] 3 aircraft

[0088] 30 Rotor unit

[0089] 300 rotor blades

[0090] 31 hull

[0091] 32 wings

[0092] 33 Battery system

[0093] K Interturn short circuit

[0094] L Air gap

[0095] N North Pole

[0096] S South Pole

[0097] U, V, W Phase q Angle of the current vector to the positive q-axis

Claims

Claims 1. A method for controlling a multi-phase electrical machine (2) having a stator (20) and a rotor (21), the method comprising: Detecting (S1) a turn-to-turn short circuit (K) of a winding (201) of the electrical machine (2) and at least one parameter describing the turn-to-turn short circuit (K); Setting (S2) an angle (q) of a current vector to the positive q-axis in the dq coordinate system of the rotor (21) with a negative d-component and a q-component other than zero based on the at least one parameter describing the winding short circuit (K); and Controlling (S3) the electrical machine (2) according to the set angle (n).

2. Method according to claim 1, wherein the angle (q) is set in a predetermined range, in particular in the range from 30° to 85°, in particular in the range from 40° to 80°.

3. The method according to claim 1 or 2, wherein the electrical machine (2) comprises a plurality of electrically separated winding systems (200A-200D) and each of the winding systems (200A-200D) has windings (201) for a plurality of, in particular three, electrical phases (U, V, W), wherein when the winding short circuit (K) is detected, it is detected in which of the winding systems (200A-200D) the winding short circuit (K) has occurred, and wherein when the electrical machine (2) is controlled, the winding system (200A-200D) with the winding short circuit (K) is controlled according to the set angle (q).

4. The method according to claim 3, wherein the angle (q) is set based on electrical currents of the winding systems (200A-200D) in which the turn short circuit (K) has not occurred.

5. Method according to one of the preceding claims, wherein the at least one parameter describing the winding short circuit (K) is a location of the Turn-to-turn short circuit (K) within a winding (201).

6. Method according to one of the preceding claims, wherein a characteristic of the winding short circuit (K) is determined by means of at least one sensor (12A, 12B).

7. Method according to one of the preceding claims, wherein the angle (q) is set using a look-up table.

8. Method according to one of the preceding claims, wherein the at least one parameter describing the winding short circuit (K) comprises a residual resistance of the winding short circuit (K).

9. The method according to claim 8, wherein in the step of adjusting the angle (q), a smaller angle (q) is adjusted for a larger residual resistance than for a smaller residual resistance.

10. Method according to claim 8 or 9, wherein the residual resistance of the winding short circuit (K) is measured by means of at least one sensor (12A, 12B).

11. A method for controlling a multi-phase electrical machine (2) having a stator (20) and a rotor (21), the method comprising: Detecting (S1) a winding short circuit (K) of a winding (201) of the electrical machine (2) and at least one parameter describing the winding short circuit (K); Setting (S2) a negative d-component and / or a q-component other than zero in the dq coordinate system of the rotor (21) based on the at least one parameter describing the winding short circuit (K); and Controlling (S3) the electrical machine (2) according to the set d-component and / or the set q-component in the dq-coordinate system.

12. Control system (1) for controlling a multi-phase electrical machine (2) with a stator (20) and a rotor (21), wherein the control system (22) is designed to carry out the method according to one of the preceding claims.

13. Electrical machine (2) comprising a stator (20), a rotor (21) and the control system (1) according to claim 12.

14. Electrical machine (2) according to claim 13, comprising a plurality of electrically separated winding systems (200A-200D), wherein each of the winding systems (200A-200D) has respective windings (201) for a plurality of electrical phases (U, V, W).

15. Aircraft (3) comprising the electric machine (2) according to claim 13 or 14 and a rotor unit (30) drivable by the electric machine (2).

16. A computer-readable storage medium (10) comprising instructions which, when executed by a processor arrangement (11), cause the processor arrangement (11) to perform the method according to any one of claims 1 to 11.

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