METHOD AND DEVICE FOR REGULATING AN ELECTRIC MACHINE

Abstract

The invention relates to a method (400) for regulating an electric machine (190) comprising a harmonic regulator (100), wherein the harmonic regulator comprises an input transformer (110), a regulator (120), and an output transformer(130). The method has the steps of: ascertaining (410) a feedback variable (Idq); transforming (420) the feedback variable (Idq); ascertaining (430) a regulating deviation; ascertaining (440) an equalization variable (UHrmc*); back-transforming (450) the equalization variable (UHrmc*); and energizing (480) at least one winding of the electric machine (190) on the basis of the actuating variable (UdqHrmc*).

Description

[0001] Description

[0002] title

[0003] Method and device for controlling an electric machine

[0004] The invention relates to a method and a device for controlling an electric machine. Furthermore, the invention relates to an electric drive system with a corresponding device and a vehicle with an electric drive system, as well as a computer program and a computer-readable storage medium.

[0005] State of the art

[0006] German patent application DE 2017 102 03691 A1 discloses a control system for an electric machine in which a disturbance variable is simultaneously compensated and a setpoint is set. For the operation of an electric machine, a phase current is set as the setpoint. The phase current is preferably set as a sinusoidal fundamental wave. During operation of the electric machine, the phase current causes the output of a uniform average torque. Due to non-ideally sinusoidal magnetic fields, winding arrangements, slotting, tooth geometry, saturation effects, and / or other effects, harmonic overtones of the torque are generated in addition to the uniform average torque. Such effects lead to force waves between the rotor and stator, which, at characteristic orders, act on the stator teeth as tangential and radial tooth forces.Due to the mechanical transmission behavior of the electric machine, these forces become perceptible as vibrations in the machine, the machine housing, and coupled components, and thus as structure-borne and airborne noise or surface vibrations. The harmonic harmonics of the torque also cause harmonics of the electric machine's electrical frequency to appear on the phase current as disturbances. To minimize these disturbances, specific harmonics are introduced and superimposed onto the regulated and predetermined phase current.

[0007] There is a need for alternative methods and devices for regulating an electrical machine, with which the harmonics can be controlled as robustly, stably, dynamically and flexibly as possible to take relevant frequency components into account.

[0008] Disclosure of the invention

[0009] A method for controlling an electric machine with a harmonic controller is provided, wherein the harmonic controller comprises an input transformation, a controller, and an output transformation. The method comprises the following steps:

[0010] Determining a feedback variable, wherein the feedback variable comprises an actual value of a harmonic of a given frequency in a field-oriented system;

[0011] Transforming the feedback signal to a constant feedback signal in a harmonic-oriented system using the input transformation;

[0012] Determining a control deviation as the difference between a predefined equalization variable and the equalization feedback variable in the harmonic-oriented system; determining a control variable using the controller as a function of the control deviation;

[0013] Inverse transformation of the input variable into a manipulated variable in the field-oriented system using the output transformation;

[0014] Energizing at least one winding of the electrical machine depending on the manipulated variable.

[0015] Field-oriented control systems are widely used to regulate electrical machines. In these systems, the alternating quantities of the phase currents to be regulated in the time domain, preferably sinusoidal, also called fundamental frequencies, are transformed mathematically into a coordinate system that rotates at the frequency of the alternating quantities. The frequency of the alternating quantities also determines the frequency of the magnetic field in the machine, so this coordinate system rotating at the frequency of the alternating quantities is also called a field-oriented system. In steady-state operation of the electrical machine, the alternating quantities in the time domain become equivalent quantities in the field-oriented system, which can be controlled using standard control engineering methods. The field-oriented system is also called a d / q coordinate system. Its d-axis points in the direction of the rotor flux, and the q-axis is perpendicular to the d-axis.A sinusoidal phase current is represented as a stator current vector, characterized by its length and direction. This current vector rotates synchronously with the rotating stator or rotor flux of the electrical machine. In the d / q coordinate system, the current vector can be represented, according to its length and direction, by two mutually perpendicular components, Id and Iq, which are equal in magnitude in the steady state.

[0016] To control an electrical machine that can be connected to or is connected to the harmonic controller, a feedback signal from the electrical machine is acquired in the field-oriented system. This feedback signal comprises a harmonic superimposed on the phase current through the electrical machine. In the field-oriented system, the phase current is constant, whereas the harmonic is alternating. Therefore, to control the harmonic, a further mathematical transformation is performed, similar to the transformation from the time domain to the field-oriented domain, using a harmonic frequency from the field-oriented system to a harmonic-oriented system. For this purpose, the feedback signal is transformed into a constant feedback signal in the harmonic-oriented system by means of an input transformation.Quantities represented as alternating quantities in the field-oriented system are represented as equal quantities in the harmonic-oriented system during steady-state operation of the electrical machine. These can be controlled using standard control engineering methods. Accordingly, a control deviation is determined as the difference between a predefined computational variable and the feedback variable in the harmonic-oriented system. A control variable is then calculated as a function of the control deviation. This control variable, representing an equal quantity in the harmonic-oriented system, is transformed back into a manipulated variable in the field-oriented system for further use in the field-oriented control of the electrical machine via the output transformation. In the field-oriented system, the manipulated variable comprises an alternating quantity, a harmonic.Finally, the procedure includes a step to energize the electrical machine depending on the manipulated variable.

[0017] Advantageously, a method for an effective harmonic controller is provided.

[0018] The formulation that a control loop variable includes a harmonic or a fundamental frequency means, within the scope of this application, that a control loop variable characterizes or describes at least one harmonic or fundamental frequency, whereby the respective control loop variable may also include further signal components, for example, a fundamental frequency and one or more harmonics, as well as any additional disturbances.

[0019] For the control of electrical machines, target phase currents are commonly specified based on determined actual phase currents, depending on a torque specification, with phase voltages being set as manipulated variables. Consequently, preferably within the scope of this application, the feedback variable (Idq), the DC feedback variable (IHrmc), the DC control variable (IH-rmc*), the machine feedback variable (labe), or the predefinable DC control variable (Idq*) each comprise a current value, and / or the DC control variable (UHrmc*), the manipulated variable (UdqHrmc*), the DC control variable, or the machine manipulated variable (Uabc*) each comprise a voltage value.

[0020] In another embodiment of the invention, the feedback variable in the field-oriented system comprises a harmonic with a positive frequency with a first amplitude and a first phase of a k-th order of an electrical frequency of the electrical machine and / or a harmonic with a negative frequency with a second amplitude and a second phase of the k-th order of an electrical frequency of the electrical machine.

[0021] The feedback variable in the field-oriented system comprises at least one harmonic. With respect to the electrical frequency of the electrical machine, the harmonic(s) have a positive and / or negative frequency of the kth order, with a respective amplitude and phase. One order that represents a relevant disturbance variable, since its amplitudes are particularly large, is, for example, the 6th order, preferably in both the positive and negative directions. For example, with an electrical frequency of the electrical machine, i.e., the fundamental frequency, of 450 Hz in the time domain, the frequency of the 6th order is 450 Hz + 450 Hz * 6 = 3150 Hz, and in the negative direction, it is 450 Hz - 6 * 450 Hz = -2250 Hz. In the field-oriented system, whose coordinate system rotates with the electrical frequency of the electrical machine, the electrical frequency of the electrical machine is mapped to 0Hz, resulting in the frequencies +2700Hz and -2700Hz for the harmonics + / - 6.Order. Depending on the magnitude of the amplitudes and the phase angle, force waves arise between the rotor and stator of the electric machine. These act as tangential and radial tooth forces on the stator teeth and cause the harmonic overtones of the torque. The more relevant orders of the feedback variables are considered for the control system, the more effectively the disturbances are corrected.

[0022] Advantageously, a feedback variable is provided for effective harmonic control.

[0023] In another embodiment of the invention, the feedback variable is transformed as a function of a determined current rotor angle of the electric machine and comprises a rotation with a rotation angle corresponding to k times the current rotor angle. The rotation is performed in a positive and / or negative direction.

[0024] The transformation from the field-oriented system to the harmonic-oriented system involves a rotation using a rotation matrix or rotation matrix.

[0025] An alternating quantity in the field-oriented system thus becomes a constant quantity in the harmonic-oriented system. For this purpose, the feedback variable is rotated by an angle corresponding to k times the current rotor angle; that is, in the case of the transformation of the 6th-order harmonic of the electrical frequency, by 6 times the current rotor angle. For the kth-order harmonics in the positive direction, the rotation is in the positive direction; for the kth-order harmonics in the negative direction, the rotation is in the negative direction. The resulting constant quantities in the harmonic-oriented system can be characterized or described using complex numbers or as complex parameters, e.g., as iPosReal, iPosImag, or as iNegReal and iNeglmag.

[0026] Besides rotation, other transformations can also be used. For example, the complex components iDSin and IDCos can be calculated by multiplying the d-current with the sine function (depending on the k-fold rotor angle) and with the cosine function, and the complex components iQSin and IQCos can be calculated by multiplying the q-current with the sine function and with the cosine function (also called frequency mixing or heterodyning).

[0027] Another alternative description can be complex harmonics with amplitude and phase of the d-current and q-current respectively.

[0028] The proportions can also be represented as an ellipse with height, width, rotation and phase by superimposing two counter-rotating pointers with different amplitudes and phases, preferably for particularly efficient calibration.

[0029] Advantageously, transformations are provided to supply equal-sized signals, enabling effective harmonic control.

[0030] In another embodiment of the invention, the predefinable equalization parameter of the harmonic-oriented system comprises a setpoint in the harmonic-oriented system for generating a harmonic on a sinusoidal phase current for energizing at least one winding of the electrical machine.

[0031] The equalization variable is a setpoint for generating a harmonic of a predefined frequency or k-th order of the electrical frequency of the electric machine. This harmonic is superimposed on the sinusoidal phase current or the fundamental frequency used to power the electric machine. This setpoint is specified analytically or using a characteristic map, particularly as a function of a torque specification, a (phase) current setpoint, an actual current value, or a determined phase current. For use in the harmonic controller in a harmonic-oriented system, it is already appropriately transformed before being specified.

[0032] Advantageously, a reference value is provided for effective harmonic control.

[0033] In another embodiment of the invention, the control variable is determined by means of the controller as a function of the control deviation by means of a control system with a PI or I controller, an inverse static or dynamic model and a PI or I controller or a controller with an inverse static or dynamic model.

[0034] When using a PI or I controller, separate controllers are used for each harmonic current component, for example iPosReal, iPosimag, iNegReal and / or iNeglmag.

[0035] When using an inverse static or dynamic model and a PI or I controller, control deviations or current deviations are converted into voltage deviations using the inverse model. Subsequently, separate PI or I controllers are used for each harmonic voltage component, such as uPos-Real, uPosimag, uNegReal, and / or uNeglmag. The model is calculated from a d / q model or field-oriented model of the electrical machine. The model can be static or also incorporate dynamic components. Control with a model that considers dynamic components is more accurate and allows for higher controller dynamics.

[0036] When using a controller with an inverse model (known as an IMC controller (internal model control) or CVD controller (complex vector design)), the inverse controller corresponds to the inverse model of the controlled system multiplied by an integrator. For a closed-loop control system T, the following applies:

[0037] GK

[0038] T = -

[0039] 1 + GK

[0040] The variables represent the following quantities:

[0041] G: Machine model K: Controller model T: Closed control loop b w : Bandwidth s: Laplace

[0042] The individual components, e.g., iPosReal, iPosImag, iNegReal, and iNeglmag, are no longer controlled separately. Only the cutoff frequency of the desired low-pass behavior of the closed-loop control system is specified.

[0043] Since this controller results in a low-pass filter behavior in the closed control loop, adding another low-pass filter to the loop is not advisable. Even with this variant, a control model that incorporates dynamic components is more accurate.

[0044] Advantageously, different controllers are provided for effective harmonic control.

[0045] In another embodiment of the invention, the feedback variable is inverted as a function of a determined current rotor angle of the electric machine. The inverted transformation comprises a rotation with an angle of rotation corresponding to k times the current rotor angle. The inverted transformation includes a rotation in the positive and / or negative direction opposite to the rotation of the feedback variable by means of the input transformation.

[0046] The transformation from the harmonic-oriented system to the field-oriented system involves a rotation using a rotation matrix or rotation matrix.

[0047] A constant quantity in the harmonic-oriented system is thus transformed into an alternating quantity in the field-oriented system. For this purpose, the control variable is rotated by an angle corresponding to k times the current rotor angle; that is, in the case of the transformation of the 6th-order harmonic of the electrical frequency, by 6 times the current rotor angle. For the kth-order harmonics in the positive direction, the rotation is in the positive direction; for the kth-order harmonics in the negative direction, the rotation is in the negative direction. Preferably, for rotations in both negative and positive directions, the resulting alternating quantities in the field-oriented system are added together to form the control variable.

[0048] In addition to rotation, other transformations, as described above, can also be used.

[0049] Advantageously, back-transformations are provided to supply alternating quantities that can be further used for effective fundamental frequency control.

[0050] In another embodiment of the method for controlling an electric machine, it further comprises a fundamental frequency controller, wherein the fundamental frequency controller includes a fundamental frequency input transformation, a fundamental frequency controller, and a fundamental frequency output transformation. The method further comprises the following steps: determining a machine feedback variable, wherein the machine feedback variable comprises an actual value of the electric machine;

[0051] Transforming the machine feedback variable to the feedback variable in the field-oriented system using the gateway input transformation; determining the gateway control deviation as the difference between a predefined gateway equalization variable and the feedback variable in the field-oriented system; determining a gateway equalization variable using the gateway controller as a function of the gateway control deviation;

[0052] Superimposing the GW equalization variable with the manipulated variable;

[0053] The output of the superposition is transformed back into a machine control variable using the GW output transformation, and at least one winding of the electric machine is energized depending on the machine control variable. In addition to harmonic control, the control system includes fundamental frequency control. The fundamental frequency control regulates the alternating quantities of the phase currents, preferably sinusoidal, to be regulated in the time domain. To control an electric machine that can be connected to or is connected to the fundamental frequency controller, a machine feedback variable, an actual value, from the electric machine is acquired in the time domain. The machine feedback variables are preferably the phase currents of an electric machine. This machine feedback variable comprises the phase current as the fundamental frequency and, as disturbances, harmonics that are superimposed on the phase current through the electric machine.In the time domain, the phase current is an alternating quantity superimposed with other alternating quantities of harmonics. To control the fundamental wave, a transformation from the time domain to the field-oriented domain is performed. For this purpose, the machine feedback variable is transformed to the feedback variable in the field-oriented system by means of a GW input transformation. Preferably, within the scope of this application, "GW" denotes the control steps and transformations used for controlling the fundamental wave. In steady-state operation of the electrical machine, alternating quantities in the time domain result in equivalent quantities in the field-oriented system. These can be controlled using the usual methods of control engineering. Accordingly, a GW control deviation is determined as the difference between a predefined GW equalization variable and the feedback variable in the field-oriented system.A harmonic controller determines a harmonic equalization variable as a function of the harmonic control deviation. The manipulated variable, as the output signal of the harmonic controller, is superimposed or added to the harmonic equalization variable in the field-oriented system. This superposition output in the field-oriented system is then back-transformed into a machine manipulated variable in the time domain using the harmonic output transformation. In the time domain, the machine manipulated variable comprises an AC quantity, a fundamental frequency, and at least one further superimposed AC quantity, a harmonic. Finally, the method includes a step for energizing the electric machine as a function of the machine manipulated variable.

[0054] Advantageously, a method for an effective fundamental and harmonic controller is provided. In another embodiment of the invention, the predefinable harmonic equalization variable of the field-oriented system comprises a setpoint for generating the fundamental frequency of a sinusoidal phase current for energizing at least one winding of the electrical machine.

[0055] The fundamental wave comparator is a setpoint for generating a fundamental wave with the electrical frequency of the electric machine for powering the electric machine. This setpoint is specified analytically or by means of a characteristic map, in particular as a function of a torque specification, a (phase) current setpoint, or an actual current value, preferably a determined phase current. For use in the fundamental wave controller in the field-oriented system, it is already appropriately transformed before being specified.

[0056] Advantageously, a GW equalization parameter is provided for effective fundamental frequency control.

[0057] Furthermore, the invention relates to a computer program which includes instructions which, when executed by a computer, cause it to perform the steps of the method described so far.

[0058] Furthermore, the invention relates to a computer-readable storage medium comprising instructions which, when executed by a computer, cause it to perform the steps of the method described so far.

[0059] Furthermore, the invention relates to a device for controlling an electric machine, comprising a computing unit and a harmonic controller, wherein the harmonic controller includes an input transformation, a controller, and an output transformation. The device is configured to perform the steps of the described method.

[0060] Advantageously, a device for effective harmonic control of an electric machine is provided. In another embodiment of the invention, the device comprises a fundamental frequency controller, wherein the fundamental frequency controller includes a harmonic input transformation, a harmonic controller, and a harmonic output transformation. The device is configured to perform the steps of the described method.

[0061] Advantageously, a device for effective, combined fundamental and harmonic control of an electric machine is provided.

[0062] Furthermore, the invention relates to an electric drive system comprising an electric machine and a described device. Such an electric drive system serves, for example, to drive an electric vehicle. The method and the device enable optimized operation of the drive train.

[0063] Furthermore, the invention relates to a vehicle with a described drive system. Advantageously, a vehicle is thus provided which includes a device with which an electric machine is effectively controlled.

[0064] It is understood that the features, properties and advantages of the method according to the invention apply accordingly to the device or drive system and the vehicle and vice versa.

[0065] Further features and advantages of embodiments of the invention will become apparent from the following description with reference to the accompanying drawings.

[0066] Brief description of the drawing

[0067] The invention will be explained in more detail below using some figures, including:

[0068] Figure 1 shows a schematic control structure of a harmonic controller. Figure 2 shows a schematic control structure for controlling an electrical machine. Figure 3 shows a schematic flowchart for a method for controlling an electrical machine.

[0069] Figure 4 shows a schematic representation of a device for controlling an electric machine.

[0070] Figure 5 shows a schematic representation of a vehicle with an electric drive system.

[0071] Embodiments of the invention

[0072] Figure 1 shows a schematic control structure of a harmonic controller 100, which comprises an input transformation 110, a controller 120, and an output transformation 130. A determined feedback variable Idq in a field-oriented system is transformed by the input transformation 110 into a DC feedback variable IHrmc in a harmonic-oriented system. A determined difference between a predefined DC feedback variable IHrmc* and the DC feedback variable IHrmc in the harmonic-oriented system is fed to the controller 120 as a control deviation and input variable. The controller 120 determines a DC output variable UHrmc* as a function of the control deviation. This DC output variable UHrmc* in the harmonic-oriented system is transformed by the output transformation 130 into a manipulated variable UdqHrmc* in the field-oriented system.Beforehand, at least one winding of an electrical machine 190 is energized depending on the control variable UdqHrmc*.

[0073] Figure 2 shows a schematic control structure for controlling an electric machine 190. The electric machine 190 is depicted as a unit consisting of an inverter 192 and an electric motor 194. The fundamental frequency controller 200 comprises a fundamental frequency input transform 210, a fundamental frequency controller 220, and a fundamental frequency output transform 230. A machine feedback variable labe of the electric machine is determined in the time domain and fed to the fundamental frequency input transform 210. The machine feedback variable labe is transformed into the feedback variable Idq in the field-oriented system by means of the fundamental frequency input transform 210. A fundamental frequency control deviation is determined as the difference between a predefined fundamental frequency control variable Idq* and the feedback variable (Idq) in the field-oriented system. A fundamental frequency control input variable is determined by means of the fundamental frequency control deviation using the fundamental frequency controller 220.As shown in Figure 1, the manipulated variable UdqHrmc* is determined in parallel using the harmonic controller 100. The ground wave equalization variable is superimposed on the manipulated variable UdqHrmc*. The output variable of the superposition in the field-oriented system is transformed into a machine manipulated variable Uabc* in the time domain by means of the ground wave output transformation 230. The machine manipulated variable Uabc*, preferably a phase voltage, is provided to the electric machine 190 for energizing at least one winding. The phase voltage is generated by means of the inverter 192 and applied to at least one winding of the electric motor 194.

[0074] Figure 3 shows a schematic flowchart for a method 400 for controlling an electric machine 190. The method begins with step 401. Preferably, in step 402, a machine feedback variable labe of the electric machine is determined in the time domain. Preferably, in step 404, this machine feedback variable labe is transformed into the field-oriented system by means of the feedback input transformation 210 to the feedback variable Idq. Preferably, in step 406, a feedback control deviation is determined as the difference between a predefinable feedback equalization variable Idq* and the feedback variable (Idq) in the field-oriented system. Preferably, in step 408, a feedback equalization variable is determined as a function of the feedback control deviation by means of the feedback controller 220.

[0075] In step 410, a feedback variable Idq is determined and, in step 420, transformed into a DC feedback variable IHrmc in a harmonic-oriented system using input transformation 110. In step 430, the difference between a predefined DC control variable IHrmc* and the DC feedback variable IHrmc is fed to the controller 120 as the control deviation and input variable. In step 440, a DC control variable UHrmc* is determined by the controller as a function of the control deviation. In step 450, this DC control variable UHrmc* in the harmonic-oriented system is transformed into a manipulated variable UdqHrmc* in the field-oriented system using output transformation. Preferably, in step 480, at least one winding of an electrical machine 190 is energized as a function of the manipulated variable UdqHrmc*.

[0076] Preferably, in step 460, the gate control variable is superimposed with the manipulated variable UdqHrmc*. Preferably, in step 470, the output variable of the superposition in the field-oriented system is transformed into a machine manipulated variable Uabc* in the time domain using the gate control output transformation 230. Preferably, in step 480, at least one winding of the electrical machine 190 is energized depending on the machine manipulated variable Uabc*. The method ends with step 490.

[0077] Figure 4 shows a schematic representation of a device 300 for controlling an electric machine 190. The electric machine 190 is depicted as a unit consisting of an inverter 192 and an electric motor 194. The device 300 comprises a harmonic controller 100 and a processing unit 310 for controlling and implementing the structure of the harmonic controller 100. The device preferably includes a fundamental frequency controller 200, which is also controlled and implemented by means of the processing unit 310. The device is configured to perform the process steps described above and thus to operate and control the electric machine 190.

[0078] Figure 5 shows a schematic representation of a vehicle 600, which includes an electric drive system 500. The drive system 500 comprises the electric machine 190, which includes an inverter 192 and an electric motor 194, and a device 300 for controlling the electric machine, as described in Figure 4. Preferably, the electric drive system includes a battery for supplying the electric drive system 500 with electrical energy.

Claims

Claims:

1. Method (400) for controlling an electrical machine (190) with a harmonic controller (100), wherein the harmonic controller comprises an input transformation (110), a controller (120) and an output transformation (130), comprising the steps: Determine (410) a feedback variable (Idq) wherein the feedback variable comprises an actual value of a harmonic of a given frequency in a field-oriented system; Transforming (420) the feedback variable (Idq) by means of the input transformation (110) to a constant feedback variable (IHrmc) in a harmonic-oriented system; Determine (430) a control deviation as the difference between a predefinable control variable (IHrmc*) and the control feedback variable (IHrmc) in the wave-oriented system; Determine (440) a constant value (UHrmc*) using the controller (120) as a function of the control deviation; Inverse transformation (450) of the rectifying variable (UHrmc*) by means of the output transformation to a manipulated variable (UdqHrmc*) in the field-oriented system; energizing (480) at least one winding of the electrical machine (190) depending on the manipulated variable (UdqHrmc*).

2. Method according to claim 1, wherein the feedback variable (Idq) in the field-oriented system comprises a harmonic with a positive frequency having a first amplitude and a first phase of a k-th order of an electrical frequency of the electrical machine (190) and / or a harmonic with a negative frequency having a second amplitude and a second phase of the k-th order of an electrical frequency of the electrical machine (190).

3. Method according to claim 2, wherein the transformation (420) of the feedback variable (Idq) is carried out as a function of a determined current rotor angle (w) of the electric machine (190) and the transformation (420) comprises a rotation with a rotation angle corresponding to k times the current rotor angle (w), and the rotation (420) is carried out in a positive direction and / or a negative direction.

4. Method according to one of the preceding claims, wherein the predefinable equalization variable (IHrmc*) of the harmonic-oriented system comprises a setpoint variable in the harmonic-oriented system, for generating a harmonic on a sinusoidal phase current for energizing at least one winding of the electrical machine (190).

5. Method according to one of the preceding claims, wherein the determination (440) of the equalization variable (UHrmc*) by means of the controller (120) as a function of the control deviation is carried out by means of a control, comprising: a PI or I controller, an inverse static or dynamic model and a PI or I controller or a controller with an inverse static or dynamic model.

6. Method according to claim 1, wherein the inverse transformation (450) of the rectifying variable (UHrmc*) is performed as a function of a determined current rotor angle (w) of the electric machine (190) and the inverse transformation (450) comprises a rotation with a rotation angle corresponding to k times the current rotor angle (w), and the inverse transformation (450) comprises a rotation in the positive and / or negative opposite direction to the rotation of the feedback variable (Idq) by means of the input transformation (110).

7. Method according to claim 1, comprising a fundamental frequency controller (200), wherein the fundamental frequency controller comprises a fundamental frequency input transformation (210), a fundamental frequency controller (220) and a fundamental frequency output transformation (230), with the following steps: Determine (402) a machine feedback variable (labe), wherein the machine feedback variable includes an actual value of the electrical machine; Transforming (404) the machine feedback variable (labe) using the GW input transformation (210) to the feedback variable (Idq) in the field-oriented system; Determine (406) the GW control deviation as the difference between a predefinable GW equalization variable (Idq*) and the feedback variable (Idq) in the field-oriented system; Determining (408) a GW equalization variable using the GW controller (220) as a function of the GW control deviation; Superimposing (460) the GW equalization variable with the manipulated variable (UdqHrmc*); inversely transforming (470) the output variable of the superposition by means of the GW output transformation (230) to a machine manipulated variable (Uabc*), and energizing (480) at least one winding of the electrical machine (190) depending on the machine manipulated variable (Uabc*).

8. Method according to claim 7, wherein the predefinable GW equalization parameter (Idq*) of the field-oriented system comprises a setpoint for generating the fundamental wave of a sinusoidal phase current for energizing at least one winding of the electrical machine (190).

9. Computer program comprising instructions which, when the program is executed by a computer, cause it to execute the method / steps of the method (400) according to claims 1 to 8.

10. Computer-readable storage medium comprising instructions which, when executed by a computer, cause the computer to execute the method / steps of the method (400) according to claims 1 to 8.

11. Device (300) for controlling an electric machine (190), comprising a computing unit (310) and a harmonic controller (100), wherein the harmonic controller includes an input transformation (110), a controller (120) and an output transformation (130), wherein the device is configured to perform the steps of the method according to any one of claims 1-6.

12. Device (300) according to claim 11, comprising a fundamental frequency controller (200), wherein the fundamental frequency controller comprises a fundamental frequency input transformation (210), a fundamental frequency controller (220) and a fundamental frequency output transformation (230), wherein the device is configured to perform the steps of the method according to any one of claims 7-8.

13. Electric drive system (500) comprising an electric machine (190) and a device (300) according to any one of claims 11 to 12.

14. Vehicle (600) comprising an electric drive system (500) according to claim 13.