METHOD AND DEVICE FOR REGULATING AN ELECTRIC MACHINE

Description

[0001] 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. State of the art

[0002] Patent applications US 2015 / 127202 A1, US 2002 / 097015 A1, and US 2006 / 038531 A1 disclose methods and devices for controlling an electric machine. Patent application DE 2017 102 036 91 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 also generated in addition to the uniform average torque.Such effects lead to force waves between the rotor and stator, which, in 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 overtones 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 preset, which are then superimposed on the preset phase current.

[0003] There is a need for alternative methods and devices for controlling 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. Disclosure of the invention

[0004] The invention is defined by the features of the independent claims.

[0005] A method for controlling an electric machine with at least one first filter and at least one second filter is provided. The method comprises the following steps: Determining a feedback variable, wherein the feedback variable comprises an actual value of a fundamental wave and a harmonic of a predetermined frequency in a field-oriented system; filtering a predefinable feedback equalization variable using the first filter; determining the filtered feedback variable without fundamental wave component as the difference between the feedback variable and the filtered feedback equalization variable; filtering the filtered feedback variable without fundamental wave component using at least one second filter; determining the filtered feedback variable without harmonic component as the sum of the output variable of the at least one second filter and the filtered feedback equalization variable; energizing at least one winding of the electrical machine depending on the filtered feedback variable without harmonic component.

[0006] 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 result in DC 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 electric machine. In the d / q coordinate system, the current vector can be represented by two mutually perpendicular components, Id and Iq, which are DC quantities in the steady state.

[0007] To control an electric machine that can be connected to or linked to the harmonic controller, a feedback signal from the electric machine is acquired in the field-oriented system. This feedback signal comprises a fundamental frequency and a superimposed harmonic. In the field-oriented system, the phase current is a DC quantity, whereas the harmonic is an AC quantity. A predefined harmonic equalization signal is filtered by the first filter. Preferably, the filtered harmonic equalization signal corresponds to a modeled fundamental frequency component from the closed-loop control system of the field-oriented control. Furthermore, a filtered feedback signal without a fundamental frequency component is determined as the difference between the feedback signal and the filtered harmonic equalization signal. The filtered feedback signal without a fundamental frequency component is then filtered by at least one second filter.By adding the output of at least one second filter and the filtered feedback control signal, a filtered feedback signal without harmonic content is determined. Subsequently, at least one winding of the electrical machine is energized depending on the feedback signal without harmonic content.

[0008] Advantageously, the feedback variable without harmonic content for the fundamental frequency controller, which is preferably based on a measured current or phase current of the electrical machine, exhibits no or only negligible harmonic content. Consequently, a method for the effective determination of a filtered feedback variable without harmonic content for a fundamental frequency controller is provided.

[0009] The formulation that a control loop variable includes a harmonic or 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 fundamental frequency and one or more harmonics, as well as any additional disturbances present.

[0010] For the control of electrical machines, target phase currents are commonly specified based on measured 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 (IHrmc*), the machine feedback variable (labc), 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.

[0011] Preferably, the feedback variable in the field-oriented system comprises a fundamental wave and 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 a k-th order of an electrical frequency of the electrical machine.

[0012] The feedback variable in the field-oriented system comprises at least one fundamental frequency and 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 electric machine, the electrical frequency of the electric machine is mapped to 0 Hz, resulting in frequencies of +2700 Hz and -2700 Hz for the harmonics of the 6th order. Depending on the magnitude of the amplitudes and the phase angle, force waves arise between the rotor and stator of the electric machine, acting as tangential and radial tooth forces on the stator teeth and causing 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 compensated.

[0013] In another embodiment of the invention, the predefinable GW equalization variable 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.

[0014] 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 a fundamental wave controller in a field-oriented system, it is already appropriately transformed before being specified.

[0015] Advantageously, a GW equalization parameter is provided to determine a feedback parameter without harmonic content for a fundamental frequency controller.

[0016] In another embodiment of the invention, filtering the filtered feedback variable without fundamental wave component by means of at least a second filter includes notch filtering of the filtered feedback variable without fundamental wave component.

[0017] Notch filters are used to selectively remove harmonic components of the difference between the feedback signal and the filtered feedback equalization signal. Preferably, several notch filters are applied sequentially or cascaded to filter harmonic components of positive and negative frequencies and / or different orders. Preferably, the coefficients of the notch filters are multiplied to provide a filter with multiple stopbands. Ideally, the notch filters are implemented digitally as IIR filters.

[0018] Advantageously, an effective method for removing the harmonic component of predefined harmonic orders is provided for the filtered feedback variable without harmonic content.

[0019] In another embodiment of the invention, filtering the predefinable GW equalization quantity by means of the first filter includes a low-pass filtering of the GW equalization quantity.

[0020] Advantageously, an effective method for removing the fundamental wave component of the GW equalization quantity is provided based on the GW equalization quantity.

[0021] In another embodiment of the invention, the filter time constant of the filter corresponds to the bandwidth of the field-oriented system or the bandwidth of the closed field-oriented control loop.

[0022] The filter time constant is set to be equal to or dependent on the settling time of the closed-loop control system of the field-oriented control.

[0023] Advantageously, a way is provided to model the course of the GW equalization variable based on the GW equalization variable.

[0024] 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; 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 the specified gateway equalization variable and the filtered feedback variable without harmonic content in the field-oriented system; determining a gateway equalization variable using the gateway controller as a function of the gateway control deviation; transforming the gateway equalization variable back to a machine control variable using the gateway output transformation; and energizing at least one winding of the electrical machine as a function of the machine control variable.

[0025] Fundamental wave control is used to regulate the alternating quantities of the phase currents, preferably sinusoidal, which are to be controlled in the time domain. To control an electric machine that can be connected to or linked with the fundamental wave 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 with superimposed disturbances from an electric machine. This machine feedback variable comprises the phase current as the fundamental wave 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 further 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 fundamental wave input transformation.Preferably, "GW" in this application denotes the control steps and transformations used for controlling the fundamental frequency. During steady-state operation of the electric machine, alternating quantities in the time domain result in DC quantities in the field-oriented system. These can be controlled using standard control engineering methods. Accordingly, a GW control deviation is determined as the difference between the specified GW equalization variable and the filtered feedback variable without harmonic content in the field-oriented system. A GW equalization variable is determined as a function of the GW control deviation using a GW controller. The GW equalization variable in the field-oriented system is then transformed back into a machine control variable in the time domain by means of the GW output transformation for further use in controlling or energizing the electric machine in the time domain.In the time domain, the machine control variable comprises an alternating quantity, a fundamental wave. Finally, the method includes a step for energizing the electrical machine depending on the machine control variable.

[0026] Advantageously, a method for an effective fundamental frequency controller is provided.

[0027] In another embodiment of the method for controlling an electric machine, it further comprises a harmonic controller, wherein the harmonic controller includes an input transformation, a controller, and an output transformation. The method has the following additional steps: Transforming the filtered feedback variable without fundamental wave component into a real-time feedback variable in a harmonic-oriented system using the input transformation; determining a control deviation as the difference between a predefined real-time feedback variable and the real-time feedback variable in the harmonic-oriented system; determining a real-time control variable using the controller as a function of the control deviation; inverting the real-time control variable into a manipulated variable in the field-oriented system using the output transformation; superimposing the real-time control variable with the manipulated variable, whereby in the step of inverting the real-time control variable into a machine manipulated variable using the real-time control output transformation, the output value of the superposition of the real-time control variable with the manipulated variable is inverted to the machine manipulated variable.

[0028] A predefined feedback control variable is filtered using the first filter. Preferably, the filtered feedback control variable corresponds to a modeled fundamental frequency component of the closed-loop field-oriented control system. A filtered feedback variable without a fundamental frequency component is determined as the difference between the feedback variable and the filtered feedback control variable. To use this feedback variable without a fundamental frequency component in a harmonic controller, the feedback variable without a fundamental frequency component is transformed into a feedback variable in a harmonic-oriented system using the input transformation.

[0029] To control a harmonic in a harmonic controller, a mathematical transformation similar to the transformation from the time domain to the field-oriented domain is performed via an input transformation. This transformation involves converting the harmonic frequency from the field-oriented system to a harmonic-oriented system. For this purpose, the feedback signal, excluding the fundamental frequency component, is transformed into a DC feedback signal in the harmonic-oriented system using an input transformation. Quantities represented as AC quantities in the field-oriented system are represented as DC quantities in the harmonic-oriented system during steady-state operation of the electrical machine. These can be controlled using standard control engineering techniques.

[0030] The transformation from the field-oriented system to the harmonic-oriented system involves a rotation using a rotation matrix. An alternating quantity in the field-oriented system thus becomes a direct 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, for 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 direct quantities in the harmonic-oriented system can be characterized or described using complex numbers or as complex parameters, e.g., as iPosReal, iPoslmag, or as iNegReal and iNeglmag.

[0031] 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).

[0032] Another alternative description can be complex harmonics with amplitude and phase of the d-current and q-current respectively.

[0033] The proportions can also be represented as an ellipse with height, width, rotation and phase by superimposing two counter-rotating pointers with different amplitude and phase, preferably for particularly efficient calibration.

[0034] Furthermore, 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 computational variable, as a DC variable 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 AC quantity, a harmonic.

[0035] Preferably, 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.

[0036] 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 energize 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 pre-transformed accordingly.

[0037] Preferably, the inverse transformation of the feedback variable is performed as a function of a determined current rotor angle of the electric machine. The inverse transformation includes a rotation with an angle of rotation equal to k times the current rotor angle. The inverse transformation includes a rotation in the positive and / or negative opposite direction to the rotation of the feedback variable by means of the input transformation. The transformation from the harmonic-oriented system to the field-oriented system includes a rotation using a rotation matrix. A DC quantity in the harmonic-oriented system thus becomes an AC quantity in the field-oriented system. For this purpose, the feedback variable is rotated with an angle of rotation equal to k times the current rotor angle; that is, in the case of the transformation of the 6th-order harmonic of the electrical frequency, with 6 times the current rotor angle.For the k-th order harmonics in the positive direction, the rotation is in the positive direction; for the k-th order harmonics in the negative direction, the rotation is in the negative direction. This results in alternating quantities in the field-oriented system. Preferably, when rotating in both the negative and positive directions, the resulting alternating quantities in the field-oriented system are added together to form the manipulated variable.

[0038] Furthermore, the manipulated variable, as the output signal of the harmonic controller, is superimposed or added to the GW equalizer variable in the field-oriented system.

[0039] This output variable from the superposition in the field-oriented system is transformed back into a machine control variable in the time domain using the GW output transformation for further use in controlling or energizing the electric machine in the time domain. In the time domain, the machine control 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 depending on the machine control variable.

[0040] Advantageously, a method for an effective fundamental and harmonic controller is provided.

[0041] 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.

[0042] 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.

[0043] Furthermore, the invention relates to a device for controlling an electric machine with a computing unit and at least one first filter and one second filter. The device is configured to perform the steps of the described method.

[0044] Advantageously, a device is provided for the effective determination of a filtered feedback variable without harmonic content for a fundamental frequency controller.

[0045] In another embodiment of the invention, the device 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 device is configured to perform the steps of the described method.

[0046] Advantageously, a device for effective harmonic control of an electric machine is provided.

[0047] In another embodiment of the invention, the device comprises 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.

[0048] Advantageously, a device for effective, combined fundamental and harmonic control of an electric machine is provided.

[0049] 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 power an electric vehicle. The method and the device enable optimized operation of the drive train.

[0050] 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.

[0051] 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.

[0052] Further features and advantages of embodiments of the invention will become apparent from the following description with reference to the accompanying drawings. Brief description of the drawing

[0053] The invention will be explained in more detail below using some figures, including: Figure 1 a schematic control structure for controlling an electrical machine Figure 2 a schematic control structure for controlling an electric machine with a harmonic controller Figure 3 a schematic control structure of a harmonic controller Figure 4 A schematically represented flowchart for a method for controlling an electrical machine. Figure 5 a schematically depicted device for controlling an electric machine Figure 6 a schematically represented vehicle with an electric drive system Embodiments of the invention

[0054] The Figure 1Figure 1 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 transformation 210, a fundamental frequency controller 220, and a fundamental frequency output transformation 230. The control structure further includes a first filter 140 and a second filter 142 and 144. A machine feedback variable labc of the electric machine is determined in the time domain and fed to the fundamental frequency input transformation 210. The machine feedback variable labc is transformed into the field-oriented system by means of the fundamental frequency input transformation 210 to the feedback variable Idq. A predefined fundamental frequency equalization variable Idq* is filtered by means of the first filter 140.A filtered feedback variable without fundamental frequency component, IdqWoFunda, is determined as the difference between the feedback variable Idq and the filtered feedback equalization variable Idq*. This filtered feedback variable is further filtered by at least one second filter 142, 144. The filtered feedback variable without harmonic component, IdqFunda, is calculated as the sum of the output of the at least one second filter 142, 144 and the filtered feedback equalization variable Idq*. The feedback control deviation is determined as the difference between the specified feedback equalization variable Idq* and the filtered feedback variable without harmonic component IdqFunda in the field-oriented system. Depending on the feedback control deviation, a feedback equalization variable is determined using the feedback controller 220. The GW equalization variable is transformed into a machine control variable Uabc* in the time domain by means of the GW output transformation 230.The machine control variable Uabc*, preferably a phase voltage, is provided to supply current to at least one winding of the electric machine 190. The phase voltage is generated by the inverter 192 and applied to at least one winding of the electric motor 194.

[0055] The Figure 2 shows a schematic control structure for controlling an electric machine with a harmonic controller 100. In contrast to the Figure 1The harmonic controller determines the manipulated variable UdqHrmc* as a function of the filtered feedback variable without fundamental frequency component IdqWoFunda. In this case, the parallel-determined harmonic equalization variable is superimposed on the manipulated variable UdqHrmc*. The output of the superposition in the field-oriented system is transformed into a machine manipulated variable Uabc* in the time domain by means of the harmonic output transformation 230. The machine manipulated variable Uabc*, preferably a phase voltage, is provided to the electric machine 190 to energize at least one winding. The phase voltage is generated by the inverter 192 and applied to at least one winding of the electric motor 194.

[0056] The Figure 3Figure 1 shows a schematic control structure of a harmonic controller 100 with a filter 140. The harmonic controller 100 comprises an input transformation 110. A predefined harmonic equalization variable Idq* is filtered by the filter 140, preferably using a low-pass filter. A feedback variable Idq is then determined in a field-oriented system. The filtered feedback variable without the fundamental component, IdqWoFunda, is calculated as the difference between the feedback variable Idq and the filtered harmonic equalization variable Idq*. This filtered feedback variable without the fundamental component, IdqWoFunda, is transformed by the input transformation 110 into a harmonic-oriented feedback variable IHrmc. The harmonic controller 100 further comprises a controller 120 and an output transformation 130.A calculated difference between a predefined computational variable IHrmc* and the feedback variable IHrmc in the harmonic-oriented system is fed to the controller 120 as a control deviation and input variable. Using the controller 120, a computational variable UHrmc* is determined as a function of the control deviation. This computational variable UHrmc* is transformed in the harmonic-oriented system to a manipulated variable UdqHrmc* in the field-oriented system by means of the output transformation. Preferably, at least one winding of an electric machine 190 is energized as a function of the manipulated variable UdqHrmc*.

[0057] The Figure 4Figure 400 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 labc of the electric machine is determined in the time domain. Preferably, in step 404, this machine feedback variable labc is transformed into the field-oriented system by means of the gate gateway input transformation 210.

[0058] In step 410, a feedback variable Idq is determined. In step 412, a predefined feedback equalization variable Idq* is filtered using the first filter 140. In step 414, the filtered feedback variable without fundamental frequency component IdqWoFunda is determined as the difference between the feedback variable Idq and the filtered feedback equalization variable Idq*. In step 416, the filtered feedback variable without fundamental frequency component IdqWoFunda is filtered using at least one second filter 142, 144. In step 418, a filtered feedback variable without harmonic component IdqFunda is determined as the sum of the output variable of the at least one second filter 142, 144 and the filtered feedback equalization variable Idq*. Preferably, in step 480 at least one winding of the electrical machine 190 is energized depending on the filtered feedback variable without harmonic content Idq Funda.

[0059] Preferably, in step 420, the filtered feedback variable without fundamental component IdqWoFunda is transformed by input transformation 110 into a real-time feedback variable IHrmc in a harmonic-oriented system. In step 430, the difference between a predefined real-time feedback variable IHrmc* and the real-time feedback variable IHrmc is fed to the controller 120 as the control deviation and input variable. In step 440, the controller determines a real-time control variable UHrmc* as a function of the control deviation. In step 450, this real-time control variable UHrmc* in the harmonic-oriented system is transformed by output transformation into a manipulated variable UdqHrmc* in the field-oriented system. Preferably, in step 452, a real-time control deviation is determined as the difference between the predefined real-time feedback variable Idq* and the filtered feedback variable without harmonic component IdqFunda in the field-oriented system.Preferably, in step 454, a gate control variable is determined using the gate controller 220, depending on the gate control deviation. Preferably, in step 460, the gate control variable is superimposed with the manipulated variable UdqHrmc*. Preferably, in step 470, the output of the superposition is transformed into a machine manipulated variable Uabc* in the time domain using the gate output transformation 230 in the field-oriented system. Preferably, in step 480, at least one winding of the electric machine 190 is energized depending on the machine manipulated variable Uabc*. The method ends with step 490.

[0060] The Figure 5Figure 1 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.

[0061] The Figure 6Figure 1 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 shown in Figure 2. Figure 5 described. Preferably, the electric drive system comprises a battery for supplying the electric drive system 500 with electrical energy.

Claims

1. Method (400) for controlling an electric machine (190) with a fundamental controller (200), wherein the fundamental controller (200) comprises at least one first filter (140) and at least one second filter (142, 144), having the steps of: ascertaining (410) a feedback variable (Idq) of the electric machine, wherein the feedback variable comprises an actual variable of a fundamental and of a harmonic of a specified frequency in a field-oriented system; filtering (412) a specifiable fundamental DC reference variable (Idq*) by means of the first filter (140); ascertaining (414) a filtered feedback variable without a fundamental component (IdqWoFunda) as the difference between the feedback variable (Idq) and the filtered fundamental DC reference variable (Idq*); filtering (416) the filtered feedback variable without a fundamental component (IdqWoFunda) by means of at least one second filter (142, 144); ascertaining (418) a filtered feedback variable without a harmonic component (IdqFunda) as the addition of the output variable of the at least one second filter (142, 144) and the filtered fundamental DC reference variable (Idq*); energizing (480) at least one winding of the electric machine (190) as a function of the filtered feedback variable without a harmonic component (IdqFunda), characterized in that the filtered feedback variable without a harmonic component is provided for the fundamental controller.

2. Method according to Claim 1, wherein the specifiable fundamental DC reference variable (Idq*) of the field-oriented system comprises a target variable for generating the fundamental of a sinusoidal phase current for energizing at least one winding of the electric machine (190).

3. Method according to either of the preceding claims, wherein filtering (416) the filtered feedback variable without a fundamental component (IdqWoFunda) by means of at least one second filter (142, 144) comprises notch filtering the filtered feedback variable without a fundamental component (IdqWoFunda).

4. Method according to one of the preceding claims, wherein filtering the specifiable fundamental DC reference variable (Idq*) by means of the first filter (140) comprises low-pass filtering the fundamental DC reference variable (Idq*).

5. Method according to Claim 1 or 2, wherein the filter time constant of the filter (140) corresponds to the bandwidth of the field-oriented system.

6. Method according to one of the preceding claims, with the fundamental controller (200), wherein the fundamental controller comprises a fundamental input transformer (210), a fundamental controller (220) and a fundamental output transformer (230), having the steps of: ascertaining (402) a machine feedback variable (labc), wherein the machine feedback variable comprises an actual variable of the electric machine; transforming (404) the machine feedback variable (labc) by means of the fundamental input transformer (210) to form a feedback variable (Idq) in the field-oriented system; ascertaining (452) a fundamental control deviation as the difference between a specified fundamental DC reference variable (Idq*) and a filtered feedback variable without a harmonic component (IdqFunda) in the field-oriented system; ascertaining (454) a fundamental DC manipulated variable by means of the fundamental controller (220) as a function of the fundamental control deviation; back-transforming (470) the fundamental DC manipulated variable by means of the fundamental output transformer (230) to form a machine manipulated variable (Uabc*), and energizing (480) at least one winding of the electric machine (190) as a function of the machine manipulated variable (Uabc*).

7. Method (400) according to Claim 6 with a harmonic controller (100), wherein the harmonic controller comprises an input transformer (110), a controller (120) and an output transformer (130), having the steps of: transforming (420) the filtered feedback variable without a fundamental component (IdqWoFunda) by means of the input transformer to form a DC feedback variable (IHrmc) in a harmonic-oriented system; ascertaining (430) the control deviation as the difference between a specifiable DC reference variable (IHrmc*) and the DC feedback variable (IHrmc) in the harmonic-oriented system; ascertaining (440) a DC manipulated variable (UHrmc*) by means of the controller (120) as a function of the control deviation; back-transforming (450) the DC manipulated variable (UHrmc*) by means of the output transformer to form a manipulated variable (UdqHrmc*) in the field-oriented system; superimposing (460) the fundamental DC manipulated variable with the manipulated variable (UdqHrmc*), wherein, in the step of back-transforming (470) by means of the fundamental output transformer (230) to form a machine manipulated variable (Uabc*), the output value of the superimposition (460) of the fundamental DC manipulated variable with the manipulated variable (UdqHrmc*) is back-transformed to form the machine manipulated variable (Uabc*).

8. Computer program, comprising instructions, which, when the program is executed by a device according to Claim 10, cause the latter to carry out the method / the steps of the method according to Claims 1 to 7.

9. Computer-readable storage medium, comprising instructions, which, when executed by a device according to Claim 10, cause the latter to carry out the method / the steps of the method according to Claims 1 to 7.

10. Device (300) for controlling an electric machine (190) with a fundamental controller (200), with a computing unit (310) and at least one first filter (140) and one second filter (142, 144), wherein the device is configured to carry out the steps of the method according to Claims 1 to 5.

11. Device (300) according to Claim 10, wherein the fundamental controller comprises a fundamental input transformer (210), a fundamental controller (220) and a fundamental output transformer (230), wherein the device is configured to carry out the steps of the method according to Claim 6.

12. Device (300) according to Claim 11, with a harmonic controller (100), wherein the harmonic controller comprises an input transformer (110), a controller (120) and an output transformer (130), wherein the device is configured to carry out the steps of the method according to Claim 7.

13. Electric drive system (500) with an electric machine (190) and a device (300) according to one of Claims 10 to 12.

14. Vehicle (600) with an electric drive system (500) according to Claim 13.