Control device, method, computer program product, electric machine and electric shaft drive train for compensating for excitation order acting on electric machine during operation of electric machine

Abstract

The invention relates to a control device (1) for compensating for an excitation order acting on an electric machine (2) during operation thereof by means of a current shaping device (3) for introducing a harmonic component into a current provided for powering the electric machine (2), in order to reduce vibrations in and / or on a stator (4) and / or on a rotor (14) of an electric machine (2), the current shaping device (3) comprises a current shaping calculation module (5) and a current shaping controller (7), which is provided in addition to a main current controller (6) that supplies the electric machine (2), the current shaping calculation module (5) has a first signal input (8) to which at least a first input signal (9) is applied during operation of the electric machine (2), and the current shaping calculation module (5) has a signal output (10) to which a first target variable signal (11) determined by the current shaping calculation module (5) on the basis of the input signal (9) is applied, the first target variable signal is transmitted to a current shaping controller (7) for current rectification.

Description

TECHNICAL FIELD

[0001] The present invention relates to a control device for compensating for excitation orders acting on an electric machine during operation of the electric machine by means of a current shaping device for introducing harmonic components into a current provided for powering the electric machine, in particular in order to reduce vibrations in and / or at a stator and / or a rotor of the electric machine. The present invention further relates to a method for compensating for excitation orders acting on an electric machine during operation of the electric machine, a computer program product, an electric machine and an electric axle drive train. BACKGROUND

[0002] DE 10 2014 007 502 A1 discloses a method for noise modulation of an electric motor, wherein the electric motor is a three-phase synchronous motor driven by means of a motor control unit using vector control, wherein actual values of the rotating current components id and iq are obtained in the controlled system, wherein id corresponds to the magnetization current of the synchronous motor and iq corresponds to the torque forming current of the synchronous motor, and wherein the actual values are compared to specified reference variables (iq_target, id_target). The difference between the actual values and the reference variables is converted via a first controller and a first transformation stage into a controlled variable in the form of a duty cycle for a PWM generator in order to adjust the actual values (iq, id) to the reference variables (iq_target, id_target). In addition, the current component (id) forming the magnetization current is adjusted to a desired acoustic state by means of an acoustic controller depending on an acoustic state which has been measured by a measuring device and forwarded to the motor control unit by means of a signal output.

[0003] Furthermore, DE 10 2009 000 928 A1 describes a method for reducing torque ripple in an electric motor. The method includes receiving a torque command and determining a cancellation current command based on the torque command. The method further includes generating a harmonic cancellation command based on the cancellation current command, wherein the harmonic cancellation command compensates for a phase shift and a damping caused by a current-regulated control module, and wherein the current-regulated control module is coupled to an inverter coupled to the electric motor. The method further includes providing the harmonic cancellation command to the current-regulated control module, wherein the current-regulated control module is configured to control the inverter in response to the harmonic cancellation command and the torque command. SUMMARY

[0004] It is an object of the present invention to provide an improved control device and an improved method for compensating for excitation orders acting on an electric machine during operation of the electric machine. It is a further object of the present invention to realize an optimized computer program product, an optimized electric machine and an optimized electric axle drive train.

[0005] This object is achieved by a control device for compensating for excitation orders acting on an electric machine during operation of the electric machine by means of a current shaping device for introducing harmonic components into a current provided for powering the electric machine, in particular in order to reduce vibrations in and / or at a stator and / or a rotor of the electric machine, wherein the current shaping device comprises a current shaping calculation module and a current shaping controller which is provided in addition to a main current controller for powering the electric machine, and the current shaping calculation module has a first signal input at which at least a first input signal is applied during operation of the electric machine and has a signal output at which a first target variable signal determined by the current shaping control module on the basis of the input signal is applied, which first target variable signal is transmitted to the current shaping controller for current shaping.

[0006] The following control device according to the invention provides various technical advantages which contribute to improved performance, smooth operation and service life of the electric machine and to a reduction of undesired side effects: The control device is for compensating for excitation orders in the operation of an electric machine by means of a current shaping device for introducing harmonic components into a current provided for powering the electric machine.

[0007] By selectively introducing harmonic components into the current for powering the electric machine, the control device can contribute to a reduction of variations in the rotational speed of the stator and / or rotor and associated vibrations. This results in lower surface speeds on the housing of the electric machine, which reduces wear and fatigue of the material. Lower surface speeds can also contribute to a reduction of the noise emissions of the electric machine.

[0008] Structural-borne noise is caused by mechanical vibrations in the electric machine and can lead to undesired noise. The control device introduces harmonic components into the current so that these vibrations can be specifically controlled and minimized. This reduces structural-borne noise and improves the acoustic environment.

[0009] Electric machines are often integrated into systems which comprise gearboxes and other mechanical components. Excitation orders acting on these components can lead to undesired acoustic anomalies, increased wear and premature failure. The use of a current shaping device to compensate for excitation orders can also contribute to a reduction of vibrations in the gearboxes connected to the electric machine.

[0010] In addition to gearboxes, other components connected to the electric machine can also be affected by excitation orders. This can also lead to undesired vibrations and damage at the other components. The control device can therefore also contribute to minimizing these vibrations in the connected components, which increases the efficiency and service life of the entire system.

[0011] For the purposes of these applications, the term "vibrations" also includes torque fluctuations of the electric machine.

[0012] A further advantage of the control device according to the present application is an improved utilization of the voltage limits. The acoustic improvement achieved by reducing the rotor / stator excitation also prevents or at least reduces significant longitudinal vibrations and humming by reducing the torque ripple.

[0013] The control device is particularly suitable for multiphase electric machines. In this context, the control device can preferably be used with permanent magnet machines, induction machines or reluctance machines.

[0014] According to an advantageous embodiment of the present application, the first input signal can represent a controlled variable, which is fed to the main current controller and comprises the currents Id_target and Iq_target.

[0015] The currents Id_target and Iq_target are terms from the theory of electric machines, particularly for three-phase electric machines such as synchronous machines or asynchronous machines. They are used to analyze the phase currents in complex AC systems and to understand power control and electrical behavior. The Id current is also called direct-axis current, which is the component of current flowing along the main axis of the magnetic field of the electric machine. The Id current produces a magnetic field in the same direction as the magnetic field of the electric machine. The Id current is responsible for the reluctance torque together with the Iq current. The Id current is also used for field weakening in permanent magnet synchronous machines.

[0016] The Iq current is also called quadrature-axis current, which is the component of current flowing perpendicular to the main axis of the electric machine. This current component produces a magnetic field perpendicular to the main magnetic field of the electric machine. By controlling the Iq current, it is possible to control the electric machine to produce the desired torque. The Id current and the Iq current together produce the resulting magnetic field in the electric machine, which rotates with the rotor movement. This control of the magnetic field makes it possible to control the torque and the power factor control of the electric machine. Controlling and regulating these currents is essential for the power control, efficiency and stability of the electric machine.

[0017] The first input signal, representing the controlled variables, is fed to the main current controller and includes the currents Id_target and Iq_target. Its substantial advantage lies in the precise and efficient control of the motor. Using Id_target and Iq_target as controlled variables allows the main current controller to precisely regulate the currents Id and Iq in the motor to the desired values. This results in precise control of motor parameters or motor states such as torque, power factor, and excitation. Using Id_target and Iq_target also allows for optimization of the motor's dynamic characteristics. This is particularly important in applications requiring rapid changes in torque or power, such as electric drives for motor vehicles. The motor can respond more quickly to changes in the controlled variables, improving controllability. Precise control of Id and Iq also helps minimize unwanted vibrations, structurally transmitted noise, and other destructive phenomena in the motor. This contributes to improved overall motor performance and operating behavior.

[0018] More preferably, the current shaping calculation module includes a second signal input at which a second input signal is applied during motor operation, wherein the second input signal specifically represents the rotational speed of the motor rotor and / or the operating temperature of the motor and / or the intermediate circuit voltage and / or the switching frequency, and the target variable signal to the current shaping controller is a function of the rotational speed of the motor rotor and / or the operating temperature of the motor and / or the intermediate circuit voltage and / or the switching frequency, thereby enabling the control device to obtain extended capabilities for adjusting and optimizing motor performance.

[0019] By incorporating the motor's rotor speed and / or operating temperature into the control loop, the current shaping controller can adjust the control of currents Id and Iq in real time to align with current operating conditions. This is particularly important because the motor's performance requirements and behavior can change during operation. Therefore, the motor can operate more efficiently and safely.

[0020] Monitoring operating temperature helps prevent motor overheating and thermal damage. If the temperature limit is reached, the current shaping controller can correspondingly reduce the power supply to protect the motor from damage. Operating temperature is also a factor for the amplitude / phase of the controlled variable, as magnetic systems can also exhibit temperature dependence. Therefore, the application of the fundamental and harmonic currents can also be adjusted according to the magnet temperature and the correspondingly changing magnetic behavior.

[0021] Taking the rotor's rotational speed into account allows the current shaping controller to control the motor so that it produces its maximum torque at different speeds. This is particularly important in automotive applications where rotor speeds can vary significantly.

[0022] According to a further preferred improvement of the invention, the target variable signal can represent amplitude and / or phase angle and / or order. Using amplitude as part of the target variable signal allows the desired power or torque of the motor to be adjusted based on the requirements of the application. This is particularly useful in applications requiring variable power output, such as those with variable loads. The phase angle of the target variable signal can be used to control the time-sequential displacement between currents Id and Iq. This enables precise control of the motor's behavior and can be useful in applications such as power factor correction and phase control. Setting the order of the target variable signal can be used to adjust the desired frequency or desired behavior of the current shaping. This is particularly important in applications with variable frequencies and harmonics. One or more harmonic components of different orders can also be applied simultaneously. The harmonic component of one of the several orders to be applied is then described by the "order" parameter, the associated amplitude in the d and / or q directions, and the phase in the d and / or q directions. Of course, different orders can also coexist, and these orders are represented accordingly by amplitude and phase.

[0023] It can also be advantageous if a set of order-dependent variables, namely amplitude (A) and phase (P), are transmitted simultaneously in both the d and q directions for different orders (n). A set of order-dependent amplitudes refers to an ordered set of amplitude values ​​specific to the d direction (Ad) and the q direction (Aq). These amplitudes can depend on the order (n), meaning that different amplitude values ​​can exist for different orders. Similar to amplitudes, there can also be an ordered set of phase values ​​that also depend on the order (n). Separate phase values ​​exist for the d direction (Pd) and the q direction (Pq). Amplitude and phase values ​​are transmitted not only for a single order but also for different orders (n) in both directions (d and q). This enables comprehensive control of signal parameters of different orders and thus very precise closed-loop or open-loop control of the motor.

[0024] Furthermore, according to an equally advantageous embodiment of the invention, the target variable signal can be determined based on the input signal, using lookup tables and / or analytical formulas stored in the current shaping calculation module. By using lookup tables and / or analytical formulas, the target variable signal can be precisely tailored to the specific requirements of the application. This allows for precise control of the motor's current shaping and other parameters to achieve the desired performance and behavior. The use of stored lookup tables and / or analytical formulas enables real-time adjustment of the target variable signal in response to constantly changing operating conditions. This is particularly useful in dynamic environments where the demands on the motor may vary. The use of analytical formulas can help make the calculation of the target variable signal more efficient, especially in cases of rapid changes or complex calculations. The lookup table allows for quick retrieval of pre-calculated values, which reduces processing time.

[0025] The object of the present invention is also achieved by the following method: the method is used to compensate for the excitation order acting on the motor during motor operation by means of a current shaping device, the current shaping device being used to introduce harmonic components into the current supplied to the motor, the method being particularly for reducing vibration in and / or at the stator and / or rotor of the motor, wherein the current shaping device includes: a current shaping calculation module and a current shaping controller, the current shaping controller being provided in addition to the main current controller for supplying power to the motor, and the current shaping calculation module having a first signal input, at least a first input signal being applied at the first signal input during motor operation, and the current shaping calculation module having a signal output, at which a first target variable signal determined by the current shaping control module based on the input signal is applied, the first target variable signal being transmitted to the current shaping controller for current shaping.

[0026] Furthermore, the object of the present invention can be achieved by a computer program product stored on a machine-readable medium or a computer data signal embodied by electromagnetic waves, having computer program code suitable for performing the method according to claim 6.

[0027] Furthermore, the object of the present invention can be achieved by an electric motor, particularly an electric motor for a drivetrain of a motor vehicle, the electric motor comprising: a motor housing; and a control unit for supplying power to the electric motor, wherein the control unit comprises a control device according to any one of claims 1 to 5.

[0028] It is also advantageous to further improve the invention so that the motor is designed as an axial flux motor or a radial flux motor.

[0029] Finally, the object of the present invention can also be achieved by an electric shaft drive system for a motor vehicle, which includes a motor having a motor housing and a transmission device coupled to the motor and housed in the transmission device housing, wherein the motor has a control unit that includes a control device according to any one of claims 1 to 5. Attached Figure Description

[0030] The invention will now be described in more detail with reference to the accompanying drawings without limiting the overall concept of the invention.

[0031] In the attached diagram: Figure 1 A schematic block diagram of the control device is shown. Figure 2 A schematic representation of a motor vehicle with an electric shaft drive system is shown. Detailed Implementation

[0032] Figure 1 A control device 1 is shown for compensating the excitation order acting on the motor 2 during operation by means of a current shaping device 3, which is used to introduce harmonic components into the current supplied to power the motor 2. In particular, the control device 1 is designed to reduce vibrations in and / or at the stator 4 and / or rotor 14 of the motor 2, as described in more detail below.

[0033] The current shaping device 3 includes a current shaping calculation module 5 and a current shaping controller 7, which is provided in addition to the main current controller 6 used to power the motor 2. For the three-phase power supply of the motor 2, the main current controller 6 is connected to the power electronics unit 15. A current sensor 13 is arranged between the power electronics unit 15 and the motor 2. This current sensor measures the corresponding currents I_U, I_V, and I_W, and feeds these currents back to the main current controller 6 as measured values. Furthermore, the rotational speed and / or rotor position of the motor 2's rotor 14 are fed back to the main current controller 6 by a rotation angle sensor 12.

[0034] The control device 1 also has a current calculation module 16, which calculates the current Id_target and Iq_target based on the setting of the rotational speed of the rotor 14, the target setting of the required torque of the motor 2, and the operating temperature of the motor 2, and transmits these currents to the current shaping calculation module 5 and the main current controller 6.

[0035] The current shaping calculation module 5 has a first signal input 8, at which at least a first input signal 9 is applied during operation of the motor 2. The current shaping calculation module 5 also has a signal output 10, at which a first target variable signal 11, determined by the current shaping calculation module 5 based on the input signal 9, is applied. This first target variable signal is transmitted to the current shaping controller 7 for current shaping purposes. In this respect, the first input signal 9 represents a controlled variable fed to the main current controller 6 and includes currents Id_target and Iq_target.

[0036] Figure 1 It is also clearly shown that the target variable signal 11 represents the amplitude, phase angle, and order. The target variable signal 11 is determined based on the input signal 9, using a lookup table and / or analysis formula stored in the current shaping calculation module 5.

[0037] The current shaping calculation module 5 also includes a second signal input 17, at which a second input signal 18 is applied during motor 2 operation. The second input signal 18 represents the rotational speed of the rotor 14 of the motor 2 and / or the operating temperature of the motor 2. A DC intermediate circuit voltage 19 can also be applied to the current shaping calculation module 5 as an additional second input signal 18. Similarly, a switching frequency 26 can be applied to the current shaping calculation module 5 as another additional input signal 18. The switching frequency 26 is the PWM / switching frequency of a power output stage, such as a B6 bridge, at which the power output stage converts DC voltage to AC voltage. Sometimes, the switching frequency 26 is also referred to as the modulation frequency.

[0038] The target variable signal 11 to the current shaping controller 7 is a function of the target variable signals "Idtarget" and "Iq target" (9) to the main current controller, and is a function of the rotational speed of the rotor 14 of the motor 2 and / or the operating temperature of the motor. When calculating the target variable signal 11, the intermediate circuit voltage 19 and / or the switching frequency 26 may also be considered. This function is provided or calculated by the current shaping calculation module 5. For example, the amplitude, phase angle, and / or order of the target variable signal 11 can then be provided as a function of the operating temperature and / or rotational speed.

[0039] based on Figure 1 The following provides a more detailed explanation of how the current shaping controller 7 interacts with the main current controller 6. The outputs of both the main current controller 6 and the current shaping controller 7 are voltages. The output voltage of the current shaping controller 7 for the nth order is designated as "Uq n" or "Ud n". For the main current controller 6, these output voltages are designated as "Ud target" and "Uq target", respectively. These target voltages are summed in the dq plane and transmitted to the power electronics unit 15 via an inverse Clark-Parker transform. Therefore, the target phase voltages are provided from the inverse Clark-Parker transform known in the art. Depending on the modulation method and the PWM / switching frequency, these target phase voltages are converted by the modulator into the switching time of the output stage.

[0040] Control device 1 also includes pulse width modulation (PWM), which is not in Figure 1As explicitly shown, the PWM function involves generating a digital signal at a constant frequency, where the ratio between the time the signal is high (logic "1") and the time it is low (logic "0") varies. This ratio is called the duty cycle. By changing the duty cycle, the PWM controller can control the average power or signal level of the connected device—in this example, power electronics unit 15 or motor 2. A higher duty cycle results in higher average power, while a lower duty cycle results in lower average power. This allows for precise control of devices with variable power or variable voltage, such as power electronics unit 15 or motor 2 in this example, depending on whether the pulse width modulation is implemented in the main current controller 6 or power electronics unit 15.

[0041] Therefore, in the application of the control device 1 shown, pulse width modulation can be used to control the speed and torque of the motor 2 by controlling the power supply in the form of pulsating voltage pulses. In the power electronics unit 15, pulse width modulation can also be used to control the output of the inverter that converts direct current to alternating current.

[0042] Therefore, in the exemplary embodiment shown, the type of pulse width modulation (PWM) depends on whether it is integrated into the power electronics unit 15 or the main current controller 6. When the PWM is integrated into the main current controller 6, six binary signals are sent to the power electronics unit 15. Otherwise, if the pulse width modulation is integrated into the power electronics unit 15, three voltages U_U, U_V, and U_W are used, and these three voltages are compared with the available intermediate circuit voltage 19. These three voltages are derived from the inverse Clark-Parker transform mentioned above.

[0043] If pulse width modulation occurs in the main current controller 6, this means that after the inverse Clark-Parker transformation is performed in the main current controller 6, the duty cycles of the three phases are also calculated, and these duty cycles are transmitted to the power electronics unit 15. The duty cycles are specified according to Duty_U, Duty_V, and Duty_W of the three connections.

[0044] The motor 2, specifically designed for the drivetrain of the motor vehicle 20, includes a motor housing 21 in which a stator 4 and a rotor 14 are housed. Furthermore, the motor 2 has a control unit 22 for supplying power to the motor 2, wherein the control unit 22 includes a control device 1 and a power electronics unit 15. Figure 1 In the embodiment shown, motor 2 is designed as a radial flux motor.

[0045] Figure 2An electric shaft drive system 23 of a motor vehicle 20 is shown. This electric shaft drive system includes a motor 2 having a motor housing 21 and a transmission device 24 coupled to the motor 2 and housed within a transmission device housing 25. The motor 2 has a control unit 22, which is as follows: Figure 1 The control device 1 described herein.

[0046] This invention is not limited to the embodiments shown in the accompanying drawings. Therefore, the above description should not be considered limiting but rather illustrative. The appended claims should be understood to indicate the presence of the stated features in at least one embodiment of the invention. This does not exclude the presence of other features. Where the claims and the above description define "first" and "second" features, this designation is used to distinguish between two features of the same type, without limiting the order of priority.

[0047] List of reference numerals 1. Control device 2 motors 3 Current Shaping Device 4. Stator 5 Current Shaping Calculation Module 6. Main Current Controller 7 Current Shaping Controller 8. Signal Input 9 Input Signals 10 Signal Output 11 Target Variable Signal 12 Rotation Angle Sensor 13 Current Sensor 14 Rotors 15 Power Electronics Unit 16 Current Calculation Module 17 Signal Input 18 Input Signals 19. Intermediate circuit voltage 20 Motor vehicles 21 Motor housing 22 Control Unit 23 Shaft Drive System 24 Transmission device 25 Transmission device housing 26 Switching frequency

Claims

1. A control device (1) for compensating the excitation order of a motor (2) during operation by means of a current shaping device (3), the current shaping device being used to introduce harmonic components into the current supplied to the motor (2), the control device being particularly for reducing vibrations in and / or at the stator (4) and / or rotor (14) of the motor (2), Its features are, The current shaping device (3) includes: a current shaping calculation module (5) and A current shaping controller (7) is provided in addition to the main current controller (6) used to power the motor (2). Furthermore, the current shaping calculation module (5) has a first signal input (8), at which at least a first input signal (9) is applied during the operation of the motor (2), and the current shaping calculation module (5) has a signal output (10), at which a first target variable signal (11) determined by the current shaping calculation module (5) based on the input signal (9) is applied, and the first target variable signal is transmitted to the current shaping controller (7) for current shaping.

2. The control device (1) according to claim 1. Its features are, The first input signal (9) represents a controlled variable that is fed to the main current controller (6) and includes currents Id_target and Iq_target.

3. The control device (1) according to claim 1 or 2. Its features are, The current shaping calculation module (5) includes a second signal input (17), at which a second input signal (18) is applied during operation of the motor (2), wherein the second input signal (18) specifically represents the rotational speed of the rotor (14) of the motor (2) and / or the operating temperature of the motor (2) and / or the intermediate circuit voltage (19) and / or the switching frequency (26), and The target variable signal (11) to the current shaping controller (7) is a function of the rotational speed of the rotor (14) of the motor (2) and / or the operating temperature of the motor and / or the intermediate circuit voltage (19) and / or the switching frequency (26).

4. The control device (1) according to any one of the preceding claims. Its features are, The target variable signal (11) represents the amplitude and / or the phase angle and / or order.

5. The control device (1) according to any one of the preceding claims. Its features are, The target variable signal (11) is determined based on the input signal (9) by means of a lookup table and / or analysis formula stored in the current shaping calculation module (5).

6. A method for compensating the excitation order of a motor (2) during operation by means of a current shaping device (3), the current shaping device being used to introduce harmonic components into the current supplied to power the motor (2), the method being particularly for reducing vibrations in and / or at the stator (4) and / or rotor (14) of the motor (2), wherein The current shaping device (3) includes: Current shaping calculation module (5) and A current shaping controller (7) is provided in addition to the main current controller (6) used to power the motor (2). Furthermore, the current shaping calculation module (5) has a first signal input (8), at which at least a first input signal (9) is applied during the operation of the motor (2), and the current shaping calculation module (5) has a signal output (10), at which a first target variable signal (11) determined by the current shaping calculation module (5) based on the input signal (9) is applied, and the first target variable signal is transmitted to the current shaping controller (7) for current shaping.

7. A computer program product or a computer data signal embodied by electromagnetic waves stored on a machine-readable medium, having computer program code suitable for performing the method according to claim 6.

8. An electric motor (2), particularly an electric motor for a drivetrain of a motor vehicle (20), said electric motor comprising: Motor housing (21); and control unit (22) for supplying power to the motor (2), Its features are, The control unit (22) includes the control device (1) according to any one of claims 1 to 5.

9. The motor (2) according to claim 8. Its features are, The motor (2) is designed as an axial flux motor or a radial flux motor.

10. An electric shaft drive system (23) for a motor vehicle (20), the electric shaft drive system comprising a motor (2) having a motor housing (21) and a transmission device (24), the transmission device being coupled to the motor (2) and housed in the transmission device housing (25), Its features are, The motor (2) has a control unit (22), which includes a control device (1) according to any one of claims 1 to 5.

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