METHOD FOR CONTROLLING A GENERATOR OF A WIND TURBINE

Abstract

Provided is a method for controlling, by means of field-oriented closed-loop control, an active rectifier which is electrically connected to a stator of a generator of a wind turbine. The generator has a rotor which is mounted so as to be rotatable about the stator and comprises the steps of determining a mechanical position of the rotor with respect to the stator, predefining DC components of rotor-fixed d and q coordinates for at least one 3-phase stator current, determining an AC component for the q coordinate at least as a function of the mechanical position of the rotor, modulating the determined AC component of the q coordinate onto the predefined DC component of the q coordinate, so that a modulated q coordinate is produced which has a DC component and an AC component, and controlling the active rectifier at least as a function of the modulated q coordinate and preferably as a function of the d coordinate.

Claims

1. A method for controlling, using field-orientated closed-loop control, an active rectifier electrically connected to a stator of a generator of a wind turbine, the stator having a rotational axis about which the rotor is mounted, comprising: determining a mechanical position of the rotor with respect to the stator; predefining directed current (DC) components of rotor-fixed d− and q coordinates for at least one three-phase stator current; determining an alternating current (AC) component for the q coordinate and/or the d coordinate at least based on the mechanical position of the rotor; modulating and/or adding: the determined AC component of the q coordinate to the predefined DC component of the q coordinate to obtain a q coordinate having DC and AC components, and/or the determined AC component of the d coordinate to the predefined DC component of the d coordinate to obtain a d coordinate having DC and AC components, and controlling the active rectifier at least based on the obtained q coordinate and/or the obtained d coordinate.

2. The method as claimed in claim 1, comprising: determining the AC component for the q coordinate and/or the d coordinate based on a working characteristic curve of the generator.

3. The method as claimed in claim 1, comprising: acquiring an electrical angle as a function of the mechanical position of the rotor and the number of pole pairs of the generator; and controlling the active rectifier based on the electrical angle.

4. The method as claimed in claim 1, wherein the generator includes a first three-phase winding system and a second three-phase winding system, the first three-phase winding system is controlled based on a first electrical angle, and the second three-phase winding system is controlled based on a second electrical angle, and the second electrical angle is different from the first electrical angle and is phase-shifted with respect to the first electrical angle.

5. The method as claimed in claim 4, wherein—the modulation and/or the addition is performed using an n-th harmonic electrical oscillation to minimize an m-th harmonic; mechanical oscillation of the generator, wherein n=m/2.

6. The method as claimed in claim 3, comprising: phase shifting the AC component of the q coordinate and/or the AC component of the d coordinate by a predetermined phase, and/or phase shifting the electrical angle by a predetermined phase angle.

7. The method as claimed in claim 1, wherein: the active rectifier includes a first three-phase circuit and a second 3-phase circuit, the first three-phase circuit is associated with a first electrical stator, and the second three-phase circuit is associated with a second electrical stator.

8. The method as claimed in claim 1, comprising: controlling the active rectifier using abc coordinates that are back-transformed from the obtained q coordinate and/or the obtained d coordinate, the abc coordinates including at least one a coordinate that causes additional rotating fields to be produced.

9. A controller for a wind turbine having at least one generator including a stator with a rotational axis about which a rotor is mounted, and the stator being electrically connected to an active rectifier actuated using an actuator, the controller comprising: a position circuit configured to determine a mechanical position of the rotor with respect to the stator and output an electrical position signal, a transformation circuit configured to predefine DC components of rotor fixed d and q coordinates for at least one three-phase stator current, and a damping circuit configured to modulate and/or add at least one AC component to a q coordinate and/or modulate and/or add at least one DC component to a d component, wherein: the AC component is determined based on the electrical position signal and/or the DC component is determined based on the electrical position signal, and the damping circuit is connected to the transformation circuit, at least one modulated q coordinate is generated which has the DC component and the AC component and is output to the actuator made available for the actuator, and/or at least one changed d coordinate is generated which has the DC component and the AC component and is output to the actuator.

10. The controller as claimed in claim 9, wherein the damping circuit has a multiplier configured to operate on the electrical position signal and generate a changed electrical position signal.

11. The controller as claimed in claim 10, wherein the damping circuit is configured to add an offset to the changed electrical position signal based on a working characteristic curve of the wind turbine to generate an offset electrical position signal.

12. The controller according to claim 11, wherein the damping circuit is configured to generate a sinusoidal signal based on the offset electrical position signal and output a changing electrical position signal.

13. The controller according to claim 12, wherein the damping circuit includes an amplitude modification circuit configured to operate on the changing electrical position signal and based on a working characteristic curve of the wind turbine to produce the AC component.

14. The controller as claimed in claim 9, further comprising: a phase shifter configured to shift the electrical position signal by a predetermined absolute value and output the phase-shifted electrical position signal to the actuator.

15. The controller according to claim 9, further comprising: a phase shifting circuit configured to shift the at least one modulated q coordinate by a predetermined absolute value and generate a first modulated q coordinate for a first three-phase stator current of a first three-phase winding system of the wind turbine and a second modulated q coordinate for a second three-phase stator current of a second three-phase winding system of the wind turbine, and/or a phase shifting circuit configured to multiply the at least one changed d coordinate by a predetermined absolute value and generate a first changed d coordinate for the first three-phase stator current of the first three-phase winding system of the wind turbine and a second changed d coordinate for the second three-phase stator current of the second three-phase winding system of the wind turbine.

16. A control system of the wind turbine, comprising the controller as claimed in claim 9.

17. (canceled)

18. A wind turbine, comprising: a generator including a stator with a rotational axis and a rotor mounted about the rotational axis, wherein the stator is electrically connected to an active rectifier, and an actuator for the active rectifier, wherein the generator includes two stators that are phase shifted by 30° and each connected to a three-phase module of the active rectifier, and the actuation unit is configured to: perform a first reverse transformation of a first modulated q coordinate and d coordinate and of a first electrical position signal for the first three-phase module of the active rectifier, and perform a second reverse transformation of a second modulated q coordinate and of the d coordinate and of a second electrical position signal for the second three-phase module of the active rectifier, wherein—the second modulated q coordinate is phase shifted by 180° with respect to the first modulated q coordinate, and the second electrical position signal is phase shifted by 30° with respect to the first electrical position signal, and/or the actuation unit is configured to: perform a first reverse transformation of a first changed d coordinate and of a q coordinate and of a first electrical position signal for the first three-phase module of the active rectifier, and a second reverse transformation of a second changed d coordinate and of the d coordinate and of a second electrical position signal for the second three-phase module of the active rectifier, wherein—the second changed d coordinate is phase shifted by 180° with respect to the first changed d coordinate, and—the second electrical position signal is phase shifted by 30° with respect to the first electrical position signal.

19. The method as claimed in claim 2, comprising: obtaining an amplitude and an offset for the AC component from the working characteristic curve.

20. The method as claimed in claim 8, wherein the additional rotating fields are produced in a radial direction in an air gap of the generator with the 5.sup.th and/or 7.sup.th harmonic of an electrical frequency.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0122] The present invention will now be explained in more detail below by way of example on the basis of exemplary embodiments and with reference to the accompanying figures, of which:

[0123] FIG. 1 shows a schematic view of a wind turbine according to an embodiment,

[0124] FIG. 2 shows a schematic sequence of a method according to an embodiment,

[0125] FIG. 3 shows a schematic design of a control unit of a wind turbine according to an embodiment,

[0126] FIG. 4 shows a schematic sequence of a further method according to an embodiment,

[0127] FIG. 5 shows a schematic design of a further control unit of a wind turbine according to an embodiment,

[0128] FIG. 6 shows a schematic design of an alternative control unit of a wind turbine according to an embodiment, and

[0129] FIG. 7 shows a schematic design of a further alternative control unit of a wind turbine according to an embodiment.

DETAILED DESCRIPTION

[0130] FIG. 1 shows a schematic view of a wind turbine 100.

[0131] The wind turbine 100 has for this purpose a tower 102 and a nacelle 104. An aerodynamic rotor 106 with three rotor blades 108 and a spinner 110 are arranged on the nacelle 104. The rotor 106 is made to rotate by the wind during operation and as a result drives a generator in the nacelle 104.

[0132] In order to operate the wind turbine, a control unit (controller) as described above or below and an actuation unit as described above or below are also provided.

[0133] The generator additionally comprises a stator with a rotational axis, and a rotor which rotates around this rotational axis, preferably is an internal rotor, wherein the stator is electrically connected to an active rectifier which can be actuated by an actuation unit (actuator).

[0134] The stator has in this context two electrical winding systems which are phase shifted by 30° and are each connected to a 3-phase module (circuit) of the active rectifier. The generator is therefore of a 6-phase design.

[0135] Furthermore, the actuation unit is configured to carry out a first reverse transformation of a first modulated q coordinate and of a d coordinate and of a first electrical position signal for the first 3-phase module (circuit) of the active rectifier and a second reverse transformation of a second modulated q coordinate and of the d coordinate and of a second electrical position signal for the second 3-phase module (circuit) of the active rectifier, wherein the second modulated q coordinate is phase shifted by 180° with respect to the first modulated q coordinate, and the second electrical position signal is phase shifted by 30° with respect to the first electrical position signal.

[0136] FIG. 2 shows a schematic sequence of a method according to an embodiment 200.

[0137] In a first step, a mechanical position of the rotor with respect to the stator is determined. This is preferably carried out by means of a mechanical angle φ.sub.mech. The mechanical angle can be determined, for example, by means of a position sensing means (position sensor). This is indicated by block 210.

[0138] Then, the mechanical angle φ.sub.mech is converted into an electrical angle φ.sub.elec. This can also be done by means of the position sensing means and as a function of the mechanical position and the number of pole pairs of the generator. This is indicated by the block 220.

[0139] In addition, an AC component q˜ is determined as a function of the mechanical position of the rotor, in particular as a function of the electrical angle φ.sub.elec. This is indicated by block 230.

[0140] Furthermore, DC components are predefined for the rotor-fixed d coordinate d− and q coordinate q− for the two 3-phase stator currents, for example, by means of a d/q transformation. This is indicated by block 240.

[0141] Then, the determined AC component q˜ is modulated onto the predefined DC component of the q coordinate q− so that a modulated q coordinate q′ is generated which has a DC component q− and an AC component q˜. This is indicated by block 250.

[0142] The active rectifier itself is then controlled as a function of the modulated q coordinate q′ and the d coordinate d−. This can be done, for example, by means of a reverse transformation of the coordinate d− and q′ into 3-phase coordinates a, b, c. This is indicated by the block 260.

[0143] In one preferred embodiment, the active rectifier is additionally controlled as a function of the electrical angle φ.sub.elec.

[0144] FIG. 3 shows a schematic design of a control unit (controller) of a wind turbine according to an embodiment 300. In particular, FIG. 3 shows a structure of such a control unit.

[0145] The wind turbine comprises a generator 310. The generator comprises a mechanical stator 312 and a mechanical rotor 314. The generator 310 is embodied here as an internal rotor, i.e., the rotor 314 is arranged within the stator 312.

[0146] The mechanical stator 312 has two 3-phase winding systems which are electrically connected to an active rectifier and preferably phase shifted by 30°.

[0147] The generator 310 is therefore also embodied with 6 phases.

[0148] The actuation of the active rectifier or of the electrical phase of the wind turbine is carried by means of the actuation unit (actuator) 320.

[0149] This control unit 320 itself is configured here to carry out a first reverse transformation a.sub.1, b.sub.1, c.sub.1 of a first modulated q coordinate I.sub.q1′ and a d coordinate d− and of a first electrical position signal φ.sub.elec1 for the first 3-phase module of the active rectifier and a second reverse transformation a.sub.2, b.sub.2, c.sub.2 of a second modulated q coordinate I.sub.q2′ and of the d coordinate d− and of a second electrical position signal φ.sub.elec2 for the second 3-phase module of the active rectifier, wherein the second modulated q coordinate I.sub.q2′ is phase shifted by 180° with respect to the first modulated q coordinate I.sub.q, and the second electrical signal φ.sub.elec2 is phase shifted by 30° with respect to the first electrical position signal φ.sub.elec1.

[0150] In order to carry out the method, a position module (circuit) 330 is also proposed which is configured to output an electrical position signal φ.sub.elec from a mechanical position φ.sub.mech of the rotor 314 with respect to the stator 312.

[0151] In addition, the control unit (controller) 300 comprises a transformation module (circuit) 340 which is configured to predefine DC components for rotor-fixed d coordinates d− and q coordinates q−, in particular for the two 3-phase stator currents of the generator 310.

[0152] Furthermore, the control unit 300 comprises a damping module (circuit) 350 for modulating at least one AC component q˜ onto a q coordinate q−, wherein the AC component q˜ is determined as a function of the electrical position signal φ.sub.elec, and the damping module 350 is connected to the transformation module 340 in such a way that a modulated q coordinate q′ is generated which has a DC component q− and an AC component q˜ which is made available for the actuation unit.

[0153] The damping module 350 itself comprises for this purpose a multiplication means (multiplier) 352 which acts on the electrical position signal φ.sub.elec in order to make available a changed electrical position signal φ1. For this purpose, the electrical position signal φ.sub.elec is multiplied by the factor 6 in order to address the operational oscillation of the generator 310 of the 12.sup.th harmonic, that is to say that which corresponds to 12 times the electrical frequency of the generator 310.

[0154] Furthermore, the damping module 350 comprises an offset 354 which acts on the changed electrical position signal φ1 of a working characteristic curve AP of the wind turbine by means of an addition to the electrical position signal, in order to make available an offset electrical position signal φ2.

[0155] In addition, the damping module 350 also has a trigonometric function sin which makes available an essentially sinusoidal signal as a function of the offset electrical position signal φ2. This signal can also be referred to as a changing electrical position signal φ3.

[0156] The damping module 350 also has an amplitude modification means (amplifier or modulator) 356 which acts on the changing electrical position signal φ3 as a function of a working characteristic curve AP of the wind turbine, in order to make available the AC component q˜.

[0157] Furthermore, the control unit 300 comprises a phase shifting module (circuit) 360 and a phase shifter 370, in order to make available the AC component q˜ for the two phase shifted electrical stators 316, 318.

[0158] The phase shifting module 360 is configured for this purpose to shift the modulated q coordinate q˜ by a predetermined absolute value of 180 in its phase, in order to make available a first modulated q coordinate q.sub.1′ for the first 3-phase stator current of the first, 3-phase winding system of the stator 316 and a second modulated q coordinate q.sub.2′ for the second 3-phase stator current of the second, 3-phase winding system of the stator 318, wherein the first winding system 316 and the second winding system 318 are phase shifted by 30°.

[0159] For this purpose, the phase shifter 370 is configured to shift the electrical position signal φ.sub.elec by a predetermined absolute value, in particular buy 30°, in its phase and to make it available at the actuation unit 320.

[0160] The actuation unit 320 itself then transforms back the variables I.sub.q1′, φ.sub.elec1, I.sub.d− to form the 3-phase coordinates a.sub.1, b.sub.1, c.sub.1 and the variables I.sub.q2′, φ.sub.elec2 and I.sub.d− to form the 3-phase coordinates a.sub.2, b.sub.2, c.sub.2.

[0161] The field-oriented closed-loop control is therefore used to control the active rectifier.

[0162] This permits the stator currents to be predefined in rotor-fixed d/q coordinates.

[0163] The currents ld− and lq− are therefore essentially equivalent variables.

[0164] In addition, a 6-phase generator 310 is proposed with 2 3-phase current systems which are offset by 30°, wherein each system has individual d/q transformations.

[0165] For the purpose of control, the variables l.sub.d1′, l.sub.q1′ are then available for the one system 316, and l.sub.d2′ and l.sub.q2′ for the other system which is offset by 30°.

[0166] It is therefore proposed to modulate the torque-forming components of the currents, specifically in such a way that the operational oscillations which occur with a frequency 12*f_el are therefore minimized.

[0167] The core point here is that the currents l.sub.q1′ and l.sub.q2′ are not modulated identically to the frequency of the 12.sup.th harmonic but rather to modulate the currents of the two partial systems with the frequency of the 6.sup.th harmonic. The phase shift of the modulation is 180°.

[0168] This can bring about stabilization of the torque and compensation of the slot cogging torque.

[0169] FIG. 4 shows a schematic sequence of a further method according to an embodiment 400.

[0170] In a first step, a mechanical position of the rotor is determined with respect to the stator. This is preferably done by means of a mechanical angle φmech. The mechanical angle can be determined, for example, by a position sensing means. This is indicated by block 410.

[0171] The mechanical angle φmech is then converted into an electrical angle φelec. This can also be done by the position sensing means and as a function of the mechanical position and the number of pole pairs of the generator. This is indicated by block 420.

[0172] In addition, an AC component d˜ is determined as a function of the mechanical position of the rotor, in particular as a function of the electrical angle φelec. This is indicated by block 430.

[0173] Furthermore, DC components for the rotor-fixed d coordinates d− and q coordinates q− are predefined for the two 3-phase stator currents, for example, by means of a d/q transformation. This is indicated by block 440.

[0174] Then, the determined AC component d is modulated or added onto the predefined DC component of the d coordinate d−, so that a changed or modulated d coordinate d′, which has a DC component d− and an AC component d˜, is generated. This is indicated by block 450.

[0175] The active rectifier itself is then controlled as a function of the changed or modulated d coordinate d′ and the q coordinate q−. This can be done, for example, by means of a reverse transformation of the coordinate d− and q′ into 3-phase coordinates a, b, c. This is indicated by block 460.

[0176] This procedure can also be described, for example, on the basis of the following equations:

[00001]$i_{q.Math..Math.1}=i_{q.Math..Math.11}$$i_{d.Math..Math.1}=i_{d.Math..Math.11}+i_{d.Math..Math.6}.Math.\sin \left(6.Math.\beta +{\varphi }_{d.Math..Math.6}\right)$$i_{q.Math..Math.2}=i_{q.Math..Math.11}$$i_{d.Math..Math.2}=i_{d.Math..Math.11}-i_{d.Math..Math.6}.Math.\sin \left(6.Math.\beta +{\varphi }_{d.Math..Math.6}\right)$$i_{a.Math..Math.1}=i_{q.Math..Math.11}.Math.\cos .Math..Math.\beta +i_{d.Math..Math.11}.Math.\sin .Math..Math.\beta +\frac{i_{d.Math..Math.6}}{2}.Math.\cos \left(5.Math.\beta +{\varphi }_{d.Math..Math.6}\right)-\frac{i_{d.Math..Math.6}}{2}.Math.\cos \left(7.Math.\beta +{\varphi }_{d.Math..Math.6}\right)$$i_{a.Math..Math.2}=i_{q.Math..Math.11}.Math.\cos \left(\beta -\frac{\pi }{6}\right)+i_{d.Math..Math.11}.Math.\sin \left(\beta -\frac{\pi }{6}\right)-\frac{i_{d.Math..Math.6}}{2}.Math.\cos \left(5.Math.\beta +\frac{\pi }{6}+{\varphi }_{d.Math..Math.6}\right)+\frac{i_{d.Math..Math.6}}{2}.Math.\cos \left(7.Math.\beta -\frac{\pi }{6}+{\varphi }_{d.Math..Math.6}\right)$

wherein this modulation is selective for the 12.sup.th harmonic.

[0177] In one preferred embodiment, the active rectifier is additionally controlled as a function of the electrical angle φelec.

[0178] FIG. 5 shows a schematic design of a further control unit of a wind turbine according to an embodiment 500. In particular, FIG. 5 shows a structure of such a control unit.

[0179] The wind turbine comprises a generator 510. The generator comprises a mechanical stator 512 and a mechanical rotor 514. The generator 510 is embodied here as an internal rotor, i.e., the rotor 514 is arranged within the stator 512.

[0180] The mechanical stator 512 has two 3-phase winding systems which are electrically connected to an active rectifier and preferably phase shifted by 30°.

[0181] The generator 510 is therefore also embodied with 6 phases.

[0182] The active rectifier or the electrical phase of the wind turbine is actuated by means of the actuation unit 520.

[0183] This control unit 520 itself is configured here to carry out a first reverse transformation a1, b1, c1 of a first changed or modulated d coordinate Id1′ and of a q coordinate q- and of a first electrical position signal φelec1 for the first 3-phase module of the active rectifier and a second reverse transformation a2, b2, c2 of a second changed or modulated d coordinate Id2′ and of the q coordinate q− and of a second electrical position signal φelec2 for the second 3-phase module of the active rectifier, wherein the second changed or modulated d coordinate Id2′ is phase shifted by 180° with respect to the first changed or modulated d coordinate Id1′, and the second electrical position signal φelec2 is phase shifted by 30° with respect to the first electrical position signal φelec1.

[0184] In order to carry out the method, a position module (circuit) 530 is also provided which is configured to output an electrical position signal φelec from a mechanical position φmech of the rotor 514 with respect to the stator 512.

[0185] In addition, the control unit 300 comprises a transformation module (circuit) 540 which is configured to predefine DC components for rotor-fixed d coordinates d−, and q coordinates q−, in particular for the two 3-phase stator currents of the generator 510.

[0186] Furthermore, the control unit 500 comprises a damping module (circuit) 550 for modulating and/or adding at least one DC component d˜ to a d coordinate d−, wherein the DC component d˜ is determined as a function of the electrical position signal φelec, and the damping module 550 is connected to the transformation module 540 in such a way that a changed or modulated d coordinate d′ is generated which has a DC component d− and an AC component d˜ and which is made available for the actuation unit.

[0187] The damping module 550 itself comprises for this purpose a multiplication means (multiplier) 552 which acts on the electrical position signal φelec, in order to make available a changed electrical position signal φ1. For this purpose, the electrical position signal φelec is multiplied by the factor 6, in order to address the operational oscillation of the generator 510 of the 12.sup.th harmonic, that is to say that which corresponds to 12 times the electrical frequency of the generator 510.

[0188] Furthermore, the damping module 550 comprises an offset 554 which acts on the changed electrical position signal φ1 as a function of a working characteristic curve AP of the wind turbine by means of addition to the electrical position signal, in order to make available an offset electrical position signal φ2.

[0189] In addition, the damping module 550 also comprises a trigonometric function sin which makes available an essentially sinusoidal signal as a function of the offset electrical position signal φ2. This signal can also be referred to as a changing electrical position signal φ3.

[0190] The damping module 550 also has an amplitude modification means 556 which acts on the changing electrical position signal φ3 as a function of a working characteristic curve AP of the wind turbine, in order to make available the AC component d˜.

[0191] Furthermore, the control unit 500 comprises a phase shifting module 560 and a phase shifter 570 in order to make available the AC component d˜ for the two phase shifted electrical stators 516, 518.

[0192] The phase shifting module 560 is for this purpose configured to shift the changed or modulated d coordinate d˜ by a predetermined absolute value of 180° in its phase, in order to make available a first changed or modulated d coordinate d1′ for the first 3-phase stator current of the first, 3-phase winding system of the stator 516 and a second changed or modulated d coordinate d2′ for the second 3-phase stator current of the second, 3-phase winding system of the stator 518, wherein the first winding system 516 and the second winding system 518 are phase shifted by 30°.

[0193] For this purpose, the phase shifter 570 is configured to shift the electrical position signal φelec by a predetermined absolute value, in particular by 30°, in its phase, and to make it available at the actuation unit 520.

[0194] The actuation unit 320 itself then transforms back the variables Id1′, φelec1, Iq− to form the 3-phase coordinates a1, b1, c1 and the variables Id2′, φelec2 and Iq− to form the 3-phase coordinates a2, b2, c2.

[0195] A field-oriented, closed-loop control is then used to control the active rectifier.

[0196] This permits the stator currents to be predefined in rotor-fixed d/q coordinates.

[0197] The currents ld− and lq− are therefore essentially equivalent variables.

[0198] In addition, a 6-phase generator 510 is proposed with 2 3-phase current systems which are offset by 30°, wherein each system has individual d/q transformations.

[0199] For the purpose of control, the variables lq−, ld1′ are then available for the one system 516 and lq− and ld2′ for the other system which is offset by 30°.

[0200] It is therefore proposed to change or modulate the torque-forming components of the currents, specifically in such a way that the operational oscillations which occur are therefore minimized with a frequency 12*f_el.

[0201] The core point here is that the currents ld1′ and ld2′ are not changed or modulated identically to the frequency of the 12.sup.th harmonic but rather to change or to modulate the currents of the two partial systems with the frequency of the 6.sup.1 harmonic. The phase shift of the modulation is 180 here.

[0202] The result is the generation of additional rotating 3-phase current fields in the radial direction in the air gap of the generator with the electrical frequency of the 5.sup.th and 7.sup.th harmonics, which ultimately affects the 12.sup.th harmonic of the magnetic radial pulses which are present.

[0203] As a result, the sound emissions of the generator can be significantly minimized.

[0204] FIG. 6 shows a schematic design of an alternative control unit of a wind turbine according to an embodiment.

[0205] In particular, FIG. 6 shows an alternative configuration to the control unit shown in FIG. 3.

[0206] In this context, in particular the variables of the d component, that is to say Id1′ and Id2′, are also made available by a method as described above.

[0207] The control unit 500 is therefore configured to carry out both methods as described above and in particular to make available both a modulated d component and a modulated q component.

[0208] FIG. 7 shows a schematic design of a further alternative control unit of a wind turbine according to an embodiment.

[0209] In particular, FIG. 7 shows an alternative configuration to the control unit shown in FIG. 5.

[0210] In this context, in particular the variables of the q component, that is to say Iq1′ and Iq2′, are also made available by a method as described above.

[0211] The control unit 500 is therefore configured to carry out both methods as described above and, in particular, to make available both a modulated d component and a modulated q component.

[0212] FIGS. 6 and 7 therefore show, in particular, a common use of the methods as described above, by means of a control unit which is configured, in particular, to carry out the methods shown in FIGS. 2 and 4.