Control device, method for compensating for orders of excitation that act on an electric machine during its operation, computer program product, electric machine, and electric axle drivetrain

Abstract

The invention relates to a control device (1) for compensating for orders of excitation that act on an electric machine (2) during its operation by means of a current-shaping apparatus (3) for introducing harmonic components into the current provided for energization of the electric machine (2), in particular in order for reducing vibrations in and / or at a stator (4) and / or a rotor (14) of the electric machine (2), wherein the current-shaping apparatus (3) comprises a current-shaping calculation module (5) and a current-shaping controller (7) that is provided in addition to a main current controller (6) for energization of the electric machine (2), and 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 electric machine (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 control module (5) on the basis of the input signal (9) is applied, said first target variable signal being transmitted to the current-shaping controller (7) for current-shaping purposes.

Description

[0001] Reqlunqsvorrichtunq, method for compensating excitation orders acting on an electrical machine during its operation, computer program product, electrical machine and electric axle drive train

[0002] The present invention relates to a control device for compensating excitation orders acting on an electrical machine during its operation by means of a current-shaping device for introducing harmonics into the current provided to power the electrical machine, in particular for reducing vibrations in and / or on a stator and / or rotor of the electrical machine. The invention further relates to a method for compensating excitation orders acting on an electrical machine during its operation, a computer program product, an electrical machine, and an electric axle drive train.

[0003] DE 10 2014 007 502 A1 discloses a method for noise modulation of an electric motor. The electric motor is a three-phase synchronous motor driven by a motor control unit using vector control. Actual values ​​for the rotated current components id and iq are obtained in a controlled system, where id corresponds to the magnetizing current and iq to the torque-generating current of the synchronous motor. The actual values ​​are compared with predetermined reference variables (iq_soll, id_soll). The differences between the actual values ​​and the reference variables are converted into manipulated variables via a first controller and a first transformation stage in a duty cycle for a PWM generator in order to regulate the actual values ​​(iq, id) to the reference variables (iq_soll, id_soll).In addition, the current component (id) forming the magnetizing current is adapted to a desired acoustic state by means of an acoustic controller as a function of an acoustic state measured by a measuring device and transmitted to the engine control unit by means of a signal output.

[0004] Furthermore, DE 10 2009 000 928 A1 describes a method for reducing the

[0005] 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 phase shift and damping introduced by the 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.

[0006] The object of the invention is to provide an improved control device and an improved method for compensating for excitation orders acting on an electrical machine during its operation. Furthermore, the object of the invention is to implement an optimized computer program product, an optimized electrical machine, and an optimized electric axle drive train.

[0007] This object is achieved by a control device for compensating for excitation orders acting on an electrical machine during its operation by means of a current shaping device for introducing harmonics into the current provided for energizing the electrical machine, in particular for reducing vibrations in and / or on a stator and / or rotor of the electrical machine, wherein the current shaping device comprises a current shape calculation module and a current shape controller present in addition to a main current controller for energizing the electrical machine, and the current shape calculation module has a first signal input to which at least one first input signal is applied during operation of the electrical machine, and the current shape calculation module has a signal output to which a first setpoint signal determined by the current shape calculation module on the basis of the input signal is applied,which is transferred to the current-shaping controller for current shaping. The control device according to the invention for compensating excitation orders during the operation of an electrical machine with a current-shaping device for introducing harmonics into the current used to power the machine offers various technical advantages that contribute to improving the performance, smoothness, and service life of the machine, as well as reducing undesirable side effects.

[0008] By selectively introducing harmonics into the current supplying the machine, the control device can help reduce the variation in rotational speed and the associated vibrations of the stator and / or rotor. This results in a lower surface speed on the machine housing, which reduces wear and fatigue of the materials. A lower surface speed can also help reduce the machine's noise emissions.

[0009] Structure-borne noise is caused by mechanical vibrations in the machine and can lead to unwanted noise. By introducing harmonics into the current, the control device can specifically control and minimize these vibrations. This reduces structure-borne noise, improving the acoustic environment.

[0010] Electrical machines are often integrated into systems that include gearboxes and other mechanical components. The impact of excitation orders on these components can lead to unwanted acoustic disturbances, increased wear, and premature failure. Using current-shaping equipment to compensate for excitation orders can also help reduce vibrations in a gearbox connected to the electrical machine.

[0011] In addition to a gearbox, other components connected to the electrical machine can also be affected by excitation orders. This can also lead to unwanted vibrations and damage there. The control device can therefore also help minimize these vibrations in connected components, increasing the efficiency and service life of the entire system.

[0012] For the purposes of these applications, the term vibrations also includes torque fluctuations of the electrical machine.

[0013] Further advantages of the control device according to the invention include better utilization of the voltage limit. The acoustic improvement achieved by reducing rotor / stator excitation also allows noticeable longitudinal vibrations and hum to be avoided or at least reduced by reducing torque ripple.

[0014] The control device is particularly suitable for multi-phase electrical machines. In this context, the control device can preferably be used with permanent magnet machines, induction machines, or reluctance machines.

[0015] According to an advantageous embodiment of the invention, it can be provided that the first input signal represents a manipulated variable passed to the main current controller and comprising the currents ld_target and lq_target.

[0016] The currents ld_target and lq_target are terms from the theory of electrical machines, particularly in three-phase machines such as synchronous or asynchronous machines. They are used to analyze the phase currents in complex AC systems and to understand the power control and behavior of the machine. The Id current, also known as the direct-axis current, is the portion of the current flowing along the principal axis of the machine's magnetic field. The Id current generates a magnetic field that is aligned with the machine's magnetic field. Together with the Iq current, the Id current is responsible for the reluctance torque. It also serves to weaken the field in a permanent magnet synchronous machine.

[0017] The Iq current, also known as quadrature axis current, is the portion of the current flowing perpendicular to the main axis of the machine. This current portion creates a magnetic field perpendicular to the main magnetic field of the machine. By controlling the Iq current, the machine can be controlled to produce the desired torque. Together, the Id and Iq currents create the resulting magnetic field in the machine, which rotates with the rotor motion. This control of the magnetic fields makes it possible to control torque and power factor in electrical machines. Controlling and adjusting these currents is critical for power control, efficiency, and stability of the electrical machine.

[0018] A key advantage of using the first input signal as a manipulated variable supplied to the main current controller and comprising the currents ld_target and lq_target is the precise and efficient control of the electric machine. Using ld_target and lq_target as manipulated variables allows the main current controller to precisely adjust the currents Id and Iq in the machine to the desired values. This results in precise control of machine parameters or machine states such as torque, power factor, and excitation. Using ld_target and lq_target also enables the machine's dynamics to be optimized. This is particularly important in applications requiring rapid changes in torque or power, such as electric drives for automotive applications. The machine can respond more quickly to changes in the manipulated variables, improving controllability.Precise control of Id and Iq can also help minimize unwanted vibrations, structure-borne noise, and other disturbing phenomena within the machine. This contributes to improving the overall performance and operating behavior of the machine.

[0019] It is further preferred that the current waveform calculation module comprises a second signal input to which a second input signal is applied during operation of the electrical machine, wherein the second input signal represents in particular the rotational speed of the rotor of the electrical machine and / or an operating temperature of the electrical machine and / or an intermediate circuit voltage and / or a switching frequency, and the setpoint signal to the current waveform controller is a function of the rotational speed of the rotor and / or the operating temperature of the electrical machine and / or the intermediate circuit voltage 19 and / or the switching frequency, whereby the control device can obtain an expanded capability for adapting and optimizing the machine performance.

[0020] By incorporating the rotor's rotational speed and / or the operating temperature of the electric machine as part of the control loop, the current shape controller can adapt the control of the currents Id and Iq in real time to the current operating conditions. This is particularly important because the power requirements and behavior of the machine can change during operation. This allows the machine to operate more efficiently and safely.

[0021] Monitoring the operating temperature can help prevent overheating and thermal damage to the electrical machine. If temperature limits are reached, the current regulator can reduce the current supply accordingly to protect the machine from damage. The operating temperature is also a factor in the amplitude / phase of the controlled variable, as the magnetic system can also exhibit temperature dependence. Therefore, the impression of the fundamental current and harmonics can also be shaped depending on the magnet temperature and the correspondingly changing magnetic behavior.

[0022] Taking the rotor's rotational speed into account allows the current regulator to control the motor so that it produces its maximum torque at different speeds. This is particularly important in automotive applications, where the rotor speed can vary significantly.

[0023] According to a further preferred development of the invention, it can also be provided that the setpoint signal represents an amplitude and / or a phase angle and / or an order. The use of an amplitude as part of the setpoint signal makes it possible to adjust the desired power or torque of the machine depending on the requirements of the application. This is particularly useful in situations where variable power outputs are needed, such as in applications with variable loads. The phase angle in the setpoint signal can be used to control the time shift between the currents Id and Iq. This enables precise control over the behavior of the machine and can be useful in applications such as power factor correction and phase control.The order specified in the setpoint signal can be used to set the desired frequency or the desired current shaping behavior. This is particularly important in applications with variable frequencies and harmonics. Harmonics of one or more orders can also be impressed simultaneously. The harmonic of one of several orders to be impressed is then described by the "order" parameter, the associated amplitude in the d and / or q direction, and the phase in the d and / or q direction. It is of course also possible for different orders to exist simultaneously, and for these to be represented accordingly by amplitudes and phases.

[0024] It can also be advantageous if a set of order-dependent quantities, namely amplitude (A) and phase (P), is transmitted in both the d-direction and the q-direction simultaneously for different orders (n). A set of order-dependent amplitudes refers to an ordered group of amplitude values ​​that are specific to the d-direction (Ad) and the q-direction (Aq). These amplitudes can be order-dependent (n), meaning that there can be different amplitude values ​​for different orders. Similar to amplitudes, there can also be an ordered group of phase values ​​that are also order-dependent (n). There are separate phase values ​​for the d-direction (Pd) and the q-direction (Pq). The amplitude and phase values ​​are transmitted not only for a single order, but for different orders (n) in both directions (d and q).This enables detailed control over the signal parameters in different orders and thus very precise regulation or control of the electrical machine.

[0025] Furthermore, according to a likewise advantageous embodiment of the invention, it can be provided that the setpoint signal is determined on the basis of the input signal using look-up tables and / or analytical formulas stored in the current waveform calculation module. By using look-up tables and / or analytical formulas, the setpoint signal can be adapted very precisely to the specific requirements of the application. This makes it possible to precisely control the current waveform and other parameters of the machine in order to achieve the desired performance and behavior. The use of stored look-up tables and / or analytical formulas makes it possible to adapt the setpoint signal in real time to respond to changing operating conditions. This is particularly useful in dynamic environments where the demands on the machine can vary.The use of analytical formulas can help make the calculation of the setpoint signal more efficient, especially for rapid changes or complex calculations. Look-up tables enable quick querying of pre-calculated values, reducing processing time.

[0026] The object of the invention is further achieved by a method for compensating for excitation orders acting on an electrical machine during its operation by means of a current shaping device for introducing harmonics into the current provided for energizing the electrical machine, in particular for reducing vibrations in and / or on a stator and / or a rotor of the electrical machine, wherein the current shaping device comprises a current shape calculation module and a current shape controller present in addition to a main current controller for energizing the electrical machine, and the current shape calculation module has a first signal input to which at least one first input signal is applied during operation of the electrical machine, and the current shape calculation module has a signal output to which a first setpoint signal determined by the current shape calculation module on the basis of the input signal is applied,which is passed to the current shape controller for current shaping.

[0027] Furthermore, the object of the invention can also be achieved by a computer program product stored on a machine-readable carrier, or computer data signal embodied by an electromagnetic wave, with a computer program code suitable for carrying out a method according to claim 6.

[0028] Furthermore, the object of the invention can be achieved by an electric machine, in particular for a drive train of a motor vehicle, comprising a motor housing and a control unit for supplying current to the electric machine, wherein the control unit comprises a control device according to one of claims 1-5.

[0029] It may also be advantageous to further develop the invention in such a way that the electrical machine is designed as an axial flux machine or radial flux machine.

[0030] Finally, the object of the invention can also be achieved by an electric axle drive train of a motor vehicle, comprising an electric machine with a motor housing and a transmission arrangement coupled to the electric machine, which is accommodated in a transmission housing, wherein the electric machine has a control unit which comprises a control device according to one of claims 1-5.

[0031] The invention will be explained in more detail below with reference to figures without limiting the general inventive concept.

[0032] It shows:

[0033] Figure 1 is a schematic block diagram of the control device,

[0034] Figure 2 shows a motor vehicle with an electric axle drive train in a schematic representation.

[0035] Figure 1 shows a control device 1 for compensating for excitation orders acting on an electrical machine 2 during its operation by means of a current-shaping device 3 for introducing harmonics into the current provided to energize the electrical machine 2. In particular, the control device 1 is designed to reduce vibrations in and / or on a stator 4 and / or rotor 14 of the electrical machine 2, which will be explained in more detail below.

[0036] The current shaping device 3 comprises a current waveform calculation module 5 and a current waveform regulator 7, which is present in addition to a main current regulator 6 for supplying current to the electrical machine 2. For the three-phase supply of current to the electrical machine 2, the main current regulator 6 is connected to power electronics 15. A current sensor 13 is arranged between the power electronics 15 and the electrical machine 2, which current sensor 13 measures the corresponding currents l_U, l_V, l_W and feeds them back as measured values ​​to the main current regulator 6. Furthermore, the rotational speed and / or the rotor position of the rotor 14 of the electrical machine 2 is fed back to the main current regulator 6 by the rotation angle sensor 12.

[0037] The control device 1 further comprises the current calculation module 16, which calculates the currents ld_target and lq_target from the specification of a rotational speed of the rotor 14, a target specification regarding the required torque of the electric machine 2 and the operating temperature of the electric machine 2 and transfers these to the current shape calculation module 5 and the main current controller 6.

[0038] The current waveform calculation module 5 has a first signal input 8, to which at least one first input signal 9 is applied during operation of the electric machine 2. The current waveform calculation module 5 further has a signal output 10, to which a first setpoint signal 11 is applied, determined by the current waveform calculation module 5 based on the input signal 9, which is transferred to the current waveform controller 7 for current shaping. The first input signal 9 represents a manipulated variable passed to the main current controller 6 and comprising the currents ld_target and lq_target.

[0039] Figure 1 also clearly shows that the setpoint signal 11 represents an amplitude, a phase angle, and an order. The setpoint signal 11 is determined based on the input signal 9 using look-up tables and / or analytical formulas stored in the current waveform calculation module 5.

[0040] The current waveform calculation module 5 further comprises a second signal input 17, to which a second input signal 18 is applied during operation of the electric machine 2, wherein the second input signal 18 represents the rotational speed of the rotor 14 of the electric machine 2 and / or an operating temperature of the electric machine 2. It is also possible for the DC intermediate circuit voltage 19 to be applied to the current waveform calculation module 5 as an additional second input signal 18. Likewise, the switching frequency 26 can be applied to the current waveform calculation module 5 as a further additional input signal 18. The switching frequency 26 is the PWM / switching frequency of the power output stage, for example, a B6 bridge, which converts the DC voltage into an AC voltage at this frequency. The switching frequency 26 is occasionally also referred to as the modulation frequency.

[0041] The setpoint signal 11 to the current waveform controller 7 is a function of the setpoint signals "Id target" and "Iq target" (9) to the main current controller and a function of the rotational speed of the rotor 14 and / or the operating temperature of the electric machine 2. The intermediate circuit voltage 19 and / or the switching frequency 26 can also be additionally taken into account when calculating the setpoint signal 11. This function is provided or calculated by the current waveform calculation module 5. For example, an amplitude, a phase angle, and / or an order of the setpoint signal 11 can then be provided as a function of the operating temperature and / or the rotational speed.

[0042] Figure 1 explains in more detail below how the current waveform controller 7 interacts with the main current controller 6. The outputs of the main current controller 6 and those of the current waveform controller 7 are voltages. The output voltages of the current waveform controller 7 are designated "Uq n" and "Ud n" for the nth order. For the main current controller 6, these are designated "Ud target" and "Uq target" respectively. These target voltages are added in the dq plane and transferred to the power electronics 15 via an inverse Clarke-Park transformation. The inverse Clarke-Park transformation, known from the prior art, thus provides the target phase voltages. These are converted into switching times of the output stage by the modulator depending on the modulation method and the PWM / switching frequency.

[0043] The control device 1 also features pulse width modulation (PWM), which, however, is not explicitly shown in Figure 1. The PWM function consists in generating a digital signal with a constant frequency, whereby the ratio between the time the signal is at a high level (logical "1") and the time it is at a low level (logical "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 to the connected device, in this case, the power electronics 15 or the electric machine 2. A higher duty cycle results in a higher average power, while a lower duty cycle results in a lower average power.This enables the precise control of devices with variable power or variable voltage, such as the power electronics 15 or the electric machine 2 in the present case, depending on whether the pulse width modulation is implemented in the main current controller 6 or the power electronics 15.

[0044] In the illustrated application of the control device 1, pulse-width modulation can thus be used to control the speed and torque of the electric machine 2 by controlling the power supply in the form of pulsating voltage pulses. In the power electronics 15, pulse-width modulation can also be used to control the output of inverters that convert direct current to alternating current.

[0045] The type of pulse width modulation (PWM) in the illustrated embodiment depends on whether it is integrated in the power electronics 15 or in the main current regulator 6. If the PWM is included in the main current regulator 6, six binary signals are sent to the power electronics 15. Otherwise—i.e., if the pulse width modulation is implemented in the power electronics 15—the three voltages U_U, U_V, and U_W are used and compared with the available intermediate circuit voltage 19. These three voltages originate from the aforementioned inverse Clarke-Park transformation.

[0046] If the pulse width modulation occurs in the main current controller 6, this means that after the inverse Clarke-Park transformation in the main current controller 6, the duty cycles for the three phases are also calculated and passed to the power electronics 15. The duty cycles are designated as Duty_U, Duty_V, and Duty_W according to the three connecting lines.

[0047] The electric machine 2, which is designed in particular for a drive train of a motor vehicle 20, comprises a motor housing 21 in which the stator 4 and the rotor 14 are accommodated. Furthermore, the electric machine 2 has a control unit 22 for supplying current to the electric machine 2, wherein the control unit 22 comprises the control device 1 and the power electronics 15. In the embodiment shown in Fig. 1, the electric machine 2 is designed as a radial flux machine.

[0048] Figure 2 shows an electric axle drive train 23 of a motor vehicle 20 comprising an electric machine 2 with a motor housing 21 and a transmission arrangement 24 coupled to the electric machine 2, which is accommodated in a transmission housing 25. The electric machine 2 has a control unit 22, which includes a control device 1 as outlined in Fig. 1.

[0049] The invention is not limited to the embodiments illustrated in the figures. The above description is therefore not to be considered restrictive, but rather explanatory. The following claims are to be understood as meaning that a stated feature is present in at least one embodiment of the invention. This does not exclude the presence of further features. Where the claims and the above description define 'first' and 'second' features, this designation serves to distinguish between two similar features without establishing a priority. List of reference symbols

[0050] 1 control device

[0051] 2 electric machine

[0052] 3 Current shaping device

[0053] 4 Stator

[0054] 5 Current waveform calculation module

[0055] 6 main current regulators

[0056] 7 current shape regulators

[0057] 8 Signal input

[0058] 9 Input signal

[0059] 10 Signal output

[0060] 11 Setpoint signal

[0061] 12 Angle sensor

[0062] 13 current sensors

[0063] 14 Rotor

[0064] 15 Power electronics

[0065] 16 Power calculation module

[0066] 17 Signal input

[0067] 18 Input signal

[0068] 19 DC link voltage

[0069] 20 motor vehicles

[0070] 21 Engine housing

[0071] 22 Control unit

[0072] 23 Axle drive train

[0073] 24 Gear arrangement

[0074] 25 Gearbox housing

[0075] 26 Switching frequency

Claims

Claims 1. Control device (1) for compensating for excitation orders acting on an electrical machine (2) during its operation by means of a current shaping device (3) for introducing harmonics into the current provided for energizing the electrical machine (2), in particular for reducing vibrations in and / or on a stator (4) and / or rotor (14) of the electrical machine (2), characterized in that the current shaping device (3) comprises a current shape calculation module (5) and a current shape controller (7) present in addition to a main current controller (6) for energizing the electrical machine (2), and the current shape calculation module (5) has a first signal input (8) to which at least one first input signal (9) is applied during operation of the electrical machine (2), and the current shape calculation module (5) has a signal output (10),to which a first setpoint signal (11) determined by the current shape calculation module (5) on the basis of the input signal (9) is applied, which is passed to the current shape controller (7) for current shaping., 2. Control device (1) according to claim 1, characterized in that the first input signal (9) represents a manipulated variable passed to the main current controller (6) and comprising the currents ld_target and lq_target.

3. Control device (1) according to claim 1 or 2, characterized in that the current waveform calculation module (5) comprises a second signal input (17) to which a second input signal (18) is applied during operation of the electrical machine (2), wherein the second input signal (18) represents in particular the rotational speed of the rotor (14) of the electrical machine (2) and / or an operating temperature of the electrical machine (2) and / or an intermediate circuit voltage (19) and / or a switching frequency (26) and the setpoint signal (11) to the current waveform controller (7) is a function of the rotational speed of the rotor (14) and / or the operating temperature of the electrical machine (2) and / or the intermediate circuit voltage (19) and / or the switching frequency (26).

4. Control device (1) according to one of the preceding claims, characterized in that the setpoint signal (11) represents an amplitude and / or a phase angle and / or an order.

5. Control device (1) according to one of the preceding claims, characterized in that the setpoint signal (11) is determined on the basis of the input signal (9) by means of look-up tables and / or analytical formulas stored in the current shape calculation module (5).

6. Method for compensating excitation orders acting on an electrical machine (2) during its operation by means of a current shaping device (3) for introducing harmonics into the current provided for energising the electrical machine (2), in particular for reducing vibrations in and / or on a stator (4) and / or a rotor (14) of the electrical machine (2), wherein the current shaping device (3) comprises a current shape calculation module (5) and a current shape controller (7) which is present in addition to a main current controller (6) for supplying current to the electrical machine (2), and the current shape calculation module (5) has a first signal input (8) to which at least one first input signal (9) is applied during operation of the electrical machine (2), and the current shape calculation module (5) has a signal output (10) to which a first setpoint signal (11) is applied, which is determined by the current shape calculation module (5) on the basis of the input signal (9), and which is transferred to the current shape controller (7) for current shaping.

7. A computer program product stored on a machine-readable medium or a computer data signal embodied by an electromagnetic wave, comprising a computer program code suitable for carrying out a method according to claim 6.

8. Electrical machine (2), in particular for a drive train of a motor vehicle (20), comprising a motor housing (21) and a control unit (22) for supplying current to the electrical machine (2), characterized in that the control unit (22) comprises a control device (1) according to one of claims 1-5.

9. Electrical machine (2) according to claim 8, characterized in that the electrical machine (2) is designed as an axial flux machine or radial flux machine.

10. Electric axle drive train (23) of a motor vehicle (20) comprising an electric machine (2) with a motor housing (21) and a transmission arrangement (24) coupled to the electric machine (2) and accommodated in a transmission housing (25), characterized in that the electric machine (2) has a control unit (22) which comprises a control device (1) according to one of claims 1-5.

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