Methods for controlling power electronics of an electric drive, control unit, and electric drive.

Abstract

The present invention relates to a method for controlling a power electronic device for an electric drive to control the torque of the rotor of an electric rotating machine, preferably an electric traction drive of a vehicle, wherein the method comprises at least the following steps: - presetting a theoretical torque to a control unit; - determining, based on direct self-regulation, at least one switching time point of a pulse width modulation unit for the control unit, depending on the theoretical stator flux of the stator of the electric rotating machine, which depends on the preset theoretical torque and the actual stator flux of the stator; - controlling the power electronic device via the pulse width modulation unit of the control unit corresponding to at least one calculated switching time point to control the torque of the rotor of the electric rotating machine to the theoretical torque.

Description

Technical Field

[0001] The present invention relates to a method for controlling a power electronic device, a control unit for an electric drive, and an electric drive. Background Technology

[0002] Motor vehicles are an important means of transportation for many people. In particular, the share of vehicles equipped with electric traction motors continues to increase. In electric vehicles, energy is stored in a battery system and supplied from the battery to the electric traction motor as needed to propel the vehicle. The electrical energy stored in the battery system, and especially the current generated therefrom, can be converted using a converter. For example, the DC power, DC current, or DC voltage of the battery system can be converted into AC power, AC current, or AC voltage using a converter. This current flow creates a rotational field in the stator coils of the electric motor, which rotates the rotor of the electric motor to drive the wheels of the electric vehicle.

[0003] The converter particularly incorporates power electronic components, such as power electronic switches, for example, insulated-gate bipolar transistors. The converter or power electronic components can be manipulated by control signals from control devices, particularly regulators and / or control devices, to rotate the rotor of an electric motor in order to drive the wheels of an electric vehicle.

[0004] Conventional current regulator-based regulation methods, such as field-oriented current regulation (FOC), use voltage as a regulation parameter and disadvantageously require, for example, minimal regulation parameter storage for stable operation. Furthermore, direct torque regulation (DTC) methods are unsuitably hampered by poor torque dynamics and stability issues with voltage limits. Model predictive regulation (MPC) requires solving complex mathematical optimization problems at each commissioning step, which disadvantageously cannot be handled in hard real-time by commercially available regulation platforms. The depletion of the power or torque potential of electric drives or their motors is therefore only feasible with these regulation methods, especially those based on digital regulation systems.

[0005] DE 11 2004 001 141 T5 discloses a control device for an electric motor. Summary of the Invention

[0006] The objective of this invention is to overcome, at least in part, the disadvantages described above. In particular, the objective of this invention is to operate electric drives or electric converters particularly efficiently, particularly simply, and with particularly high efficiency. Furthermore, the objective of this invention is particularly advantageous to operate electric rotary machines with electric drives in a range of flux reduction, and preferably particularly advantageously in locked operation.

[0007] The foregoing task is to provide a method for controlling the torque of the rotor of an electric drive, preferably an electric traction drive of a vehicle, via power electronics for manipulating an electric drive, and a control unit for an electric drive, preferably an electric traction drive of a vehicle, wherein the control unit is configured to perform the foregoing method and an electric drive solution. Herein, the features and details described in conjunction with the method according to the invention are equally applicable to the features and details described in conjunction with the control unit and / or electric drive according to the invention, and vice versa, so that the disclosures regarding the various aspects of the invention are always mutually referential.

[0008] According to a first aspect, the present invention discloses a method for operating power electronics for an electric drive, for controlling the torque of the rotor of an electric rotating machine, preferably an electric traction drive for a vehicle, wherein the electric rotating machine is particularly in a flux reduction range. The method according to the invention includes, as at least one step, presetting a theoretical torque to a control unit. Furthermore, as another step, the method includes determining at least one switching time point for a pulse width modulation unit for the control unit based on direct self-regulation, by means of the control unit, at least depending on the theoretical stator flux of the stator of the electric rotating machine, which depends on the preset theoretical torque and on the actual stator flux. Additionally, as a step, the method includes operating the power electronics via the pulse width modulation unit of the control unit corresponding to at least one calculated switching time point, for controlling the rotor torque of the electric rotating machine to the theoretical torque.

[0009] Provided it is technically meaningful, the method steps described above and below may be implemented individually, together, once, multiple times, in parallel in time, and / or sequentially in any order.

[0010] In particular, the method according to the invention is applicable to electric rotary machines operating in the flux reduction range.

[0011] Power electronic devices include, in particular, at least one power electronic switch, such as, for example, an insulated-gate bipolar transistor. Furthermore, electric rotating machines, especially three-phase rotating machines, are also included.

[0012] Electric drives, especially electric traction drives. Furthermore, electric drives are particularly used in vehicles, preferably motor vehicles, and most preferably automobiles such as cars or trucks.

[0013] Furthermore, controlling the torque of the rotor of the electric rotary machine driven by the electric actuator, especially adjusting the torque of the rotor of the electric rotary machine driven by the electric actuator.

[0014] The electric rotary machine particularly has an armature adjustment range as a first speed range and a flux reduction range as a second speed range, wherein preferably the second speed range has a higher speed than the first speed range. The flux reduction range is particularly the speed range of the electric rotary machine or its rotor, wherein the stator flux of the electric rotary machine is reduced, especially with respect to the armature adjustment range. In the flux reduction range, the intermediate circuit voltage of the electric actuator can no longer be increased, wherein an increase in the speed of the electric rotary machine or its rotor leads to a reduction in the stator flux of the electric rotary machine.

[0015] The preset theoretical torque is achieved, in particular, through an external control device. Preferably, the preset theoretical torque is achieved through an external control device of the vehicle, such as a control unit.

[0016] The switching time point for the pulse width modulation unit is determined, particularly through a direct self-regulation unit of the control unit, where the determination is based on direct self-regulation. Furthermore, determining the switching time point can be understood as calculation, preferably by means of an algorithm. Specifically, the direct self-regulation unit compares the theoretical stator flux with the actual stator flux to determine or calculate the switching time point for the pulse width modulation unit. Furthermore, determining the at least one switching time point can be understood, in particular, as determining multiple switching time points for the pulse width modulation unit. Moreover, determining the switching time point may, in particular, depend at least additionally on the electrical parameters of the electric actuator, such as, for example, current and / or voltage and / or electrical frequency, and / or on the mechanical parameters of the electric actuator, such as, for example, rotor position and / or rotor speed. The electric actuator may include at least one or more sensors for acquiring the electrical parameters of the electric actuator, and / or at least one or more sensors for acquiring the mechanical parameters of the electric actuator.

[0017] In particular, in direct self-regulation, the stator flux space vector of the electric rotary machine is guided on a trajectory by means of a voltage space vector (Spannungsraumzeigern), wherein the voltage space vector is connected to the stator flux space vector set in the electric rotary machine. In direct self-regulation, the transition between voltage space vectors of the stator flux space vector is determined in particular. According to the invention, the determination, and especially the calculation, of at least one switching time point for the pulse width modulation unit based on direct self-regulation is particularly carried out in such a way that the stator flux space vector of the electric rotary machine is guided with amplitude on a trajectory, especially a hexagonal trajectory, for determining, and especially calculating, at least one switching time point for the pulse width modulation unit. The amplitude of the trajectory, especially the hexagonal trajectory, is given in particular by the theoretical stator flux.

[0018] Advantageously, the hysteresis regulator that operates continuously in time using the method according to the invention can be replaced by pulse width modulation, which determines the switching time point according to the invention. Furthermore, this allows for a simple, discontinuous implementation of direct self-regulation with particularly high regulation power on a simple microcontroller. Moreover, the power or torque potential of the electric drive, or the electric rotating machine particularly in the flux reduction range, is particularly well exhausted. Thus, the electric drive or electric converter according to the invention can operate particularly efficiently, particularly simply, and with particularly high efficiency. Furthermore, the electric rotating machine according to the invention can operate or regulate in locked operation, particularly advantageously and preferably particularly advantageously, in the flux reduction range.

[0019] Advantageously, in the method according to the invention, the switching time point is determined independently of a time-continuously operating hysteresis regulator. This makes controlling the torque of the rotor of the electric rotary machine (especially in the flux reduction range) particularly advantageous. Preferably, the determination of the switching time point is performed without a time-continuously operating hysteresis regulator. In other words, the control unit, in particular, does not have a time-continuously operating hysteresis regulator for determining the switching time point for the pulse width modulation unit.

[0020] Advantageously, in the method according to the invention, the actual stator flux of the stator used to determine the switching time point is determined by means of flux prediction, preferably by means of an algorithm. Thus, controlling the torque of the rotor of the electric rotating machine (especially in the flux reduction range) of the electric actuator can be particularly advantageous. The actual stator flux of the stator is determined by means of flux prediction, especially by estimating the actual stator flux, preferably by means of an algorithm. Preferably, the flux prediction of the actual stator flux is performed by a flux prediction unit of the control unit. The determination or calculation of the switching time point is particularly carried out such that the determined switching time point substantially coincides with the switching time point of the hysteresis regulator that is time-continuous within the pulse width modulation interval. The flux prediction or flux prediction unit can determine, preferably estimate, the actual stator flux of the electric actuator's stator, particularly based at least on the electrical parameters of the electric actuator, such as, for example, current and / or voltage and / or electrical frequency, and / or on the mechanical parameters of the electric actuator, such as, for example, the rotor position and / or rotor speed of the rotor.

[0021] Particularly advantageously, in the method according to the invention, the theoretical stator flux can be determined based on both the theoretical load angle and the actual load angle of the electric rotating machine, wherein the actual load angle is determined, in particular, by means of flux prediction of the electric rotating machine. Thus, controlling the torque of the rotor of the electric rotating machine (especially in the flux reduction range) is particularly advantageous. The load angle is particularly the angle between the stator flux of the stator and the rotor flux of the rotor of the electric rotating machine. Determining the theoretical stator flux, in particular, based on both the theoretical load angle and the actual load angle of the electric rotating machine, is preferably done by means of an algorithm. In particular, the theoretical stator flux is determined by a load angle adjustment unit. Furthermore, the flux prediction of the actual load angle is preferably performed by a flux prediction unit of the control unit. The flux prediction or flux prediction unit can determine, preferably estimate, the actual load angle of the electric driving machine, particularly based at least on electrical parameters of the electric driving machine, such as, for example, current and / or voltage and / or electrical frequency, and / or on mechanical parameters of the electric driving machine, such as, for example, rotor position and / or rotor angle.

[0022] According to another preferred embodiment, in the method according to the invention, the actual load angle of the electric rotary machine can be adjusted to the theoretical load angle by means of the theoretical stator flux as an adjustment parameter. Thus, determining the switching time point for the pulse width modulation unit can be particularly advantageous, wherein the determination is based on direct self-regulation. Preferably, the actual load angle of the electric rotary machine is adjusted to the theoretical load angle in a closed adjustment loop by means of the theoretical stator flux as an adjustment parameter.

[0023] Advantageously, in the method according to the invention, the theoretical load angle of the electric rotating machine depends on a preset theoretical torque and is determined based on the theoretical stator flux. Therefore, controlling the rotor torque of the electric rotating machine (especially in the flux reduction range) is particularly advantageous. The theoretical load angle is determined, in particular, by means of an algorithm, depending on the preset theoretical torque and the theoretical stator flux. Specifically, the theoretical load angle is determined by a load angle reference unit. Preferably, the theoretical load angle of the electric rotating machine depends on the preset theoretical torque and the theoretical stator flux based on a pre-calculated characteristic curve of the electric drive or the electric rotating machine, especially a pre-calculated stator flux-torque-load angle characteristic curve. The pre-calculated characteristic curve can be stored in the memory of the control unit. Furthermore, the maximum permissible stator flux for the direct self-adjusting unit and / or for the load angle adjustment unit is additionally determined, particularly by the load angle reference unit, wherein the maximum permissible stator flux is determined based on the pre-calculated characteristic curve. Therefore, controlling the rotor torque of the electric rotating machine (especially in the flux reduction range) is particularly advantageous.

[0024] Advantageously, in the method according to the invention, the theoretical stator flux can be determined by a preset theoretical torque limit to the maximum permissible stator flux. The maximum permissible stator flux is particularly used for limiting the adjustment parameters of the load angle adjustment unit. The maximum permissible stator flux is thus particularly used for limiting the armature adjustment range, wherein preferably the maximum permissible stator flux is not exceeded. Advantageously, this ensures reliable and / or efficient operation of the electric drive, especially within the flux reduction range of the electric rotating machine.

[0025] Particularly advantageously, in the method according to the invention, a preset theoretical torque can be set at a maximum adjustable theoretical torque when the preset theoretical torque is unattainable due to the state parameters of the electric actuator. Thus, controlling the torque of the rotor of the electric rotating machine (especially in the flux reduction range) is particularly advantageous. In particular, the theoretical torque is limited to the maximum adjustable theoretical torque when, for example, the preset theoretical torque via an external control device, is outside the maximum adjustable theoretical torque value due to the state parameters of the electric actuator. The state parameters of the electric actuator are, in particular, the electrical parameters of the electric actuator, such as, for example, the current and / or voltage of the electric actuator, preferably the intermediate circuit voltage.

[0026] According to another preferred embodiment, the method according to the invention allows the power electronics to be controlled by a control unit so that the electric rotary machine operates with locked timing. This keeps the switching frequency of the power electronics particularly low, and is especially advantageous for controlling the torque of the rotor of the electric rotary machine (particularly in the flux reduction range). Locked timing can also be understood, in particular, as fundamental frequency timing or six-step operation.

[0027] According to a second aspect, the present invention discloses a control unit for an electric drive, preferably for an electric traction drive of a vehicle, wherein the control unit is configured to perform the method according to the invention.

[0028] The control unit particularly includes a load angle reference unit and / or a load angle adjustment unit and / or a direct self-adjustment unit and / or a pulse width modulation unit and / or a flux prediction unit and / or power electronics, wherein the control unit particularly constitutes an electric converter for an electric drive. Preferably, the control unit, which includes a load angle reference unit, a load angle adjustment unit, a direct self-adjustment unit, a pulse width modulation unit, a flux prediction unit, and power electronics, constitutes an electric converter for an electric drive.

[0029] In particular, the theoretical load angle is determined by the load angle reference unit from the theoretical stator flux determined by the load angle adjustment unit and the preset theoretical torque, wherein preferably the theoretical load angle and the maximum permissible stator flux are determined.

[0030] Furthermore, the theoretical stator flux can be determined from the theoretical load angle and the actual load angle determined by the load angle reference unit through the load angle adjustment unit, wherein the actual load angle is determined by the flux prediction unit, wherein the maximum permissible stator flux determined by the load angle reference unit is taken into consideration in determining the theoretical stator flux.

[0031] In particular, one or more switching time points for the pulse width modulation unit can be determined, preferably calculated, from the theoretical stator flux determined by the load angle adjustment unit and the actual stator flux determined by the magnetic flux prediction unit through the direct self-adjustment unit.

[0032] In particular, according to the present invention, the at least one switching time point and / or theoretical stator flux and / or actual stator flux and / or maximum permissible stator flux and / or theoretical load angle and / or actual load angle are determined or calculated by a corresponding algorithm.

[0033] The method according to the invention, and especially the algorithm of the method according to the invention, is implemented, at least in part, in a control unit using software technology. The control unit therefore particularly has a computer equipped with a processor for at least partially implementing the method according to the invention. Furthermore, the computer may additionally have memory. The computer is preferably a microcontroller.

[0034] The control unit according to the second aspect of the invention therefore has the same advantages as it has already described for the method according to the first aspect of the invention.

[0035] According to a third aspect, the present invention discloses an electric drive, particularly an electric traction drive for vehicles, wherein the electric drive has an electric rotating machine with a stator and a rotor. Furthermore, the electric drive includes power electronics and a control unit according to the invention for operating the power electronics, for controlling the torque of the rotor of the electric rotating machine.

[0036] The electric drive according to the third aspect of the invention thus has the same advantages as it has been described for the method according to the first aspect of the invention or the control unit according to the second aspect of the invention. Attached Figure Description

[0037] Further improvements to the invention derive from the subsequent description of some embodiments thereof, which are schematically illustrated in the accompanying drawings. All features and / or advantages derived from the claims, description, or drawings, along with structural details, spatial arrangements, and method steps, may be important to the invention not only in themselves but also in different combinations. It should be noted that the drawings are merely descriptive and should not be construed as limiting the invention in any way.

[0038] in:

[0039] Figure 1 An embodiment of the electric actuator according to the invention is illustrated schematically.

[0040] Figure 2 An embodiment of the control unit according to the present invention is illustrated schematically, and

[0041] Figure 3 An embodiment of the method according to the present invention is shown.

[0042] In the following figures, the same reference numerals are used for the same technical features even in different embodiments. Detailed Implementation

[0043] Figure 1 An embodiment of an electric drive 100 according to the invention, particularly an electric traction drive for vehicles, is schematically shown, wherein the electric drive 100 has an electric rotating machine 90 with a stator 92 and a rotor 94. Furthermore, the electric drive 100 has a power electronics 80 and a control unit 20 constructed according to the invention for operating the power electronics 80, for controlling the torque of the rotor 94 of the electric rotating machine 90. The control unit 20 particularly includes a load angle reference unit 30 and / or a load angle adjustment unit 40 and / or a direct self-adjustment unit 50 and / or a pulse width modulation unit 60 and / or a flux prediction unit 70 and / or the power electronics 80, wherein the control unit 20 particularly constructs an electric converter. The control unit 20, particularly through an external control device (not shown), presets a theoretical torque T*, to which the rotor 94 of the electric rotating machine 90 (especially in the flux reduction range of the electric rotating machine 90) should be adjusted. Furthermore, in Figure 1 In this process, the power electronics 80 is additionally electrically connected to the vehicle's external electrical power source 110, such as, for example, the vehicle's battery system, to supply electrical energy to the electric rotary machine 90. Specifically, the switching time point t is determined. swt, abc This may at least additionally depend on the electrical parameters of the electric drive 100, such as, for example, current and / or voltage and / or electrical frequency, and / or on the mechanical parameters of the electric drive 100, such as, for example, the rotor position and / or rotor speed of the rotor 94. The electric drive 100 may therefore include, in particular, at least one or more sensors for acquiring the electrical parameters of the electric drive 100 and / or at least one or more sensors for acquiring the mechanical parameters of the electric drive 100. Figure 1 The example presents, by way of example, at least one sensor additionally acquires the electrical parameters of the rotor 94 and / or at least one sensor acquires the mechanical parameters of the rotor 94, and transmits them to the control unit 20 or to the load angle reference unit 30 and / or the load angle adjustment unit 40 and / or the direct self-adjustment unit 50 and / or the pulse width modulation unit 60 and / or the magnetic flux prediction unit 70. Furthermore, in Figure 1 The example presents, by way of example, at least one additional sensor acquires electrical parameters of at least one circuit for electrically connecting the power electronics 80 and the electric rotary machine 90, and transmits them to the control unit 20 or to the load angle reference unit 30 and / or the load angle adjustment unit 40 and / or the direct self-adjustment unit 50 and / or the pulse width modulation unit 60 and / or the magnetic flux prediction unit 70.

[0044] Figure 2 An embodiment of a control unit 20 according to the invention for an electric drive 100, preferably for an electric traction drive of a vehicle, is schematically illustrated. The control unit 20 is configured to execute a method according to the invention for manipulating the power electronics 80 of the electric drive 100 to control the torque of the rotor 94 of the electric rotary machine 90 of the electric drive 100. In this embodiment, the control unit 20 includes a load angle reference unit 30, a load angle adjustment unit 40, and a direct self-adjustment unit 50. Additionally, the control unit 20 may include a flux prediction unit 70 and / or a pulse width modulation unit 60 and / or the power electronics 80. The theoretical load angle δ* and the maximum permissible stator flux ψ* are determined from the theoretical stator flux ψ* determined by the load angle adjustment unit 40 and the preset theoretical torque T* by the load angle reference unit 30. MTPC Furthermore, the load angle adjustment unit 40 uses the theoretical load angle δ* and the actual load angle δ* determined by the load angle reference unit 30 to adjust the load angle. est (especially the actual load angle δ) est The theoretical stator flux ψ* is determined by the flux prediction unit 70, wherein the maximum permissible stator flux ψ* is determined, in particular, by the load angle reference unit 30. MTPC Consideration is given to determining the theoretical stator flux ψ*. Additionally, the theoretical stator flux ψ* determined by the load angle adjustment unit 40 is obtained via the direct self-adjustment unit 50, and the actual stator flux ψ* is determined by the flux prediction unit 70. L-L,est Determine, and preferably calculate, one or more switching time points t for the pulse width modulation unit 60. swt, abc .

[0045] Figure 3 An embodiment of the method according to the invention is schematically illustrated for controlling the power electronics 80 of the electric drive 100 to control the torque of the rotor 94 of the electric rotating machine 90 of the electric drive 100. The method according to the invention, as a first step, includes presetting a theoretical torque T* 320 to the control unit 20. As another step, the method includes direct self-regulation via the control unit 20, depending at least on the theoretical stator flux ψ* of the stator 92 of the electric rotating machine, which depends on the preset theoretical torque T* and on the actual stator flux ψ of the stator 92.L-L,est Determine at least one switching time point t for the pulse width modulation unit 60 of the control unit 20. swt, abc In particular, a hysteresis regulator that operates independently of time is used to determine the 322 switching time point t. swt, abc Furthermore, especially regarding the determination of the 322 switching time point t swt, abc Additional actual stator flux ψ L-L,est It can be determined by means of magnetic flux prediction. In addition, it can also depend, in particular, on the theoretical load angle δ* of the electric rotating machine 90 and on the actual load angle δ of the electric rotating machine 90. est Determine the theoretical stator flux ψ*, wherein the actual load angle δ of the electric rotary machine is preferably 90°. est The theoretical stator flux ψ* is used as an adjustment parameter to adjust to the theoretical load angle δ*. In the method according to the invention, it is also conceivable that the theoretical load angle δ* of the additional electric rotary machine 90 depends on a preset theoretical torque T* and is determined by the theoretical stator flux ψ*. Furthermore, the theoretical stator flux ψ* can be additionally limited to the maximum permissible stator flux ψ*, particularly depending on the preset theoretical torque T*. MTPC Above. Similarly, in the method according to the invention, the preset theoretical torque T* can be additionally set to the maximum adjustable theoretical torque T*. max When the preset theoretical torque T* is unattainable due to the state parameters of the electric drive 100. Furthermore, the method includes, as another step, a switching time point t corresponding to at least one calculated value. swt, abc The pulse width modulation unit 60 of the control unit 20 controls the 324 power electronic devices 80 to control the torque of the rotor 94 of the electric rotary machine 90 to the theoretical torque T*. Furthermore, the 324 power electronic devices 80 can also be controlled, particularly by the control unit 20, to allow the electric rotary machine 90 to operate with locked timing.

[0046] Reference Symbol List

[0047] 20 Control Units

[0048] 30 Load Angle Reference Unit

[0049] 40 Load Angle Adjustment Unit

[0050] 50 Direct Self-Regulation Units

[0051] 60 Pulse Width Modulation Unit

[0052] 70 Magnetic Flux Prediction Units

[0053] 80 Power Electronic Devices

[0054] 90 Electric Rotary Machine

[0055] 92 stator

[0056] 94 Rotor

[0057] 100 Electric Drive

[0058] 110 External electrical energy

[0059] t swt, abc Switch time points (multiple)

[0060] ψ* Theoretical stator flux

[0061] ψ L-L,est Actual stator flux

[0062] ψ MTPC Maximum permissible stator flux

[0063] δ* Theoretical load angle

[0064] δ est Actual load angle

[0065] T* Theoretical Torque

[0066] T* max Maximum adjustable theoretical torque

[0067] 320 Preset theoretical torque

[0068] 322 Determine the switching time point

[0069] 324 Control power electronics

Claims

1. A method for controlling a power electronic device (80) of an electric drive (100) to control the torque of the rotor (94) of an electric rotary machine (90) of the electric drive (100), wherein, The method comprises at least the following steps: - The theoretical torque (T*) is preset (320) at the control unit (20). - Based on direct self-regulation, the control unit (20) depends at least on the theoretical stator flux (ψ*) of the stator (92) of the electric rotary machine (90) which depends on a preset theoretical torque (T*) and the actual stator flux (ψ) of the stator (92). L-L,est ), determine (322) at least one switching time point (t) for the pulse width modulation unit (60) of the control unit (20). swt, abc ), - The pulse width modulation unit (60) of the control unit (20) corresponds to at least one calculated switching time point (t). swt, abc The power electronics (80) is controlled (324) to control the torque of the rotor (94) of the electric rotary machine (90) to the theoretical torque (T*). The theoretical stator flux (ψ*) depends on the theoretical load angle (δ*) of the electric rotary machine (90) and also depends on the actual load angle (δ) of the electric rotary machine (90). est )Sure.

2. The method according to claim 1, characterized in that, The electric drive (100) is the electric traction drive of the vehicle.

3. The method according to claim 1, characterized in that, The electric rotary machine (90) is in the range of reduced flux.

4. The method according to claim 1, characterized in that, The switching time point (t) is determined by a hysteresis controller that operates independently of time (322). swt, abc ).

5. The method according to any one of claims 1-4, characterized in that, The actual stator flux (ψ) of the stator (92) L-L,est In order to determine the switching time point (t) mentioned in (322) swt, abc It is determined by using magnetic flux prediction.

6. The method according to any one of claims 1-4, characterized in that, The actual load angle (δ) est The magnetic flux is determined by means of the electric rotating machine (90).

7. The method according to claim 6, characterized in that, The actual load angle (δ) of the electric rotary machine (90) est The theoretical stator flux (ψ*) is adjusted to the theoretical load angle (δ*) by means of the theoretical stator flux (ψ*).

8. The method according to claim 6, characterized in that, The theoretical load angle (δ*) of the electric rotary machine (90) depends on the preset theoretical torque (T*) and is determined by the theoretical stator flux (ψ*).

9. The method according to any one of claims 1-4, characterized in that, The theoretical stator flux (ψ*) depends on the preset theoretical torque (T*) and is limited to the maximum permissible stator flux (ψ). MTPC )superior.

10. The method according to any one of claims 1-4, characterized in that, When the preset theoretical torque (T*) is unattainable due to the state parameters of the electric drive (100), the preset theoretical torque (T*) is set to the maximum adjustable theoretical torque (T*). max )superior.

11. The method according to any one of claims 1-4, characterized in that, The power electronics (80) is controlled (324) by the control unit (20) so that the electric rotary machine (90) operates with locked timing, wherein locked timing can be understood as base frequency timing or six-step operation.

12. A control unit (20) for an electric drive (100), wherein the control unit (20) is configured to perform the method according to any one of claims 1-11.

13. The control unit (20) according to claim 12, characterized in that, The electric drive (100) is the electric traction drive of the vehicle.

14. An electric drive (100), wherein the electric drive (100) has: - An electric rotary machine (90) with a stator (92) and a rotor (94), - Power electronic devices (80), - A control unit (20) for manipulating a power electronics device (80) to control the torque of the rotor (94) of an electric rotary machine (90), wherein the control unit (20) is designed according to claim 12 or 13.

15. The electric drive (100) according to claim 14, characterized in that, The electric drive (100) is an electric traction drive for a vehicle.

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