Method for calibrating a sound generated by a vibration generator when actuating an electric machine, and power electronics of the electric machine

Abstract

The present invention relates to a method for calibrating a sound generated by a vibration generator (1) when an electric machine (EM) is activated with a phase current having an id-current component (id) and an iq-current component (iq) which are adjusted by a current controller (2), wherein the magnitudes of the id-current component (id) and the iq-current component (iq) are varied in order to generate the sound, the generated sound being evaluated with respect to a wattage applied in each case in relation to the generated acoustic power, and wherein a distribution ratio of the modified current components (id / iq) in the phase current is stored to allow the generation of a sound having maximum acoustic power at the lowest possible wattage. The invention further relates to a method for activating an electric machine (EM) and to power electronics of the electric machine (EM).

Description

[0001] ZF Friedrichshafen AG 215119-DE-NP Friedrichshafen 2025-02-05

[0002] Method for calibrating a tone generated by a vibration oscillator when controlling an electric machine and power electronics of the electric machine

[0003] The present invention relates to a method for calibrating a tone generated by a vibration generator when driving an electric machine with a phase current having an id current component and an adapted iq current component adjusted by a current controller. Furthermore, the invention relates to a method for driving an electric machine with a phase current having values ​​of an id current component and an iq current component adjusted by a current controller, wherein a vibration is superimposed on the phase current to generate a predetermined tone. The invention also relates to power electronics of an electric machine for carrying out a method for driving the electric machine.

[0004] In automotive engineering, it is well known that electric machines are used to propel vehicles. For example, a three-phase AC motor can be used as an electric machine with field-oriented control, which typically employs a Clarke-Park transformation. In this transformation, the three phase currents U, V, and W of the AC motor are converted into a two-dimensional coordinate system with id and iq current components. This coordinate system rotates with the rotor of the AC motor and therefore exhibits constant values ​​over time. In a process called "current shaping" to achieve improved smooth running and acoustics of the AC motor, an oscillation is introduced into the iq current component, which is out of phase with the oscillations generated by the machine topology.This method can also be used to deliberately generate acoustic anomalies in the form of tones and noises. For example, it is known from publication DE 102017 101 303 A1 that the iq current component is used to introduce a vibration.

[0005] It has been shown that the acoustics of vehicles powered by three-phase motors represent an area for development that requires improvement. ZF Friedrichshafen AG 215119-DE-NP Friedrichshafen 2025-02-05

[0006] The aim is to minimize background noise or to generate tones or sounds to provide acoustic warning signals or feedback to the driver or pedestrians. For this purpose, the control of the three-phase motor can be used to generate a specific tone, sound, or noise. However, it has been shown that the achievable amplitude of the vibration is limited by the available voltage level when controlling the three-phase motor.

[0007] The present invention is based on the objective of proposing a method for calibrating a generated tone and a method for controlling an electric machine as well as power electronics for an electric machine, which determine and / or use optimal conditioning parameters for generating the tone.

[0008] This problem is solved according to the invention by the features of claim 1, 5, or 6. Advantageous and claimed embodiments are described in the respective dependent claims, the description, and the drawings.

[0009] The problem underlying the invention is solved by a method for calibrating a tone generated by a vibration generator in the control of an electric machine with a phase current having an id current component and an adapted iq current component adjusted by a current controller. The values ​​of the id current component and the iq current component for generating the tone are varied, wherein the generated tone is evaluated with respect to the generated acoustic power at a given electrical power input, and wherein a distribution ratio of the changed current components is stored for the phase current for generating a tone with maximum acoustic power at minimum electrical power input.

[0010] In this way, the proposed method optimizes the generation of tone or sound, making it significantly more energy-efficient and acoustically effective. As part of the acoustic calibration, an operating point optimization is performed. ZF Friedrichshafen AG 215119-DE-NP Friedrichshafen 2025-02-05

[0011] the current shaping conditioning with regard to the maximum achievable sound pressure level or acceleration level.

[0012] Within the framework of the proposed method, a characteristic map is determined from the stored percentage distribution values ​​of the modified id current components and iq current components. In this way, the frequency generation of the applied oscillation is controlled in such a way that the generated tone achieves maximum efficiency in terms of the ratio of electrical power input to acoustic power output.

[0013] After the optimal operating point for generating a maximum tone has been determined, the procedure involves further calibration to determine an optimal phase angle for the oscillation imprinted on the phase current by varying the phase angle of the imprinted oscillation in such a way that an increase in amplitude due to the imprinted oscillation in the peak value range of the generated phase current is prevented or minimized.

[0014] In a specific implementation of the proposed method, the values ​​of the id current component and the iq current component, which are adjusted by a current controller, are changed to generate a test tone by varying the values ​​of the id current component and the iq current component, and the respective generated tone or...

[0015] Sound is recorded and evaluated with regard to the generated acoustic power and the electrical power input. Subsequently, a percentage distribution value of the changed current components is stored for a tone with maximum acoustic power at minimum electrical power input. Then, peak value ranges of the phase current are recorded, and the phase angle of the applied oscillation is modified such that a phase angle at maximum acoustic power and minimum electrical voltage is recorded.

[0016] The problem underlying the invention is also achieved by a method for controlling an electric machine with a phase current having values ​​of an id current component and an iq current component adapted by a current controller. ZF Friedrichshafen AG 215119-DE-NP Friedrichshafen 2025-02-05

[0017] solved, wherein a phase current is imprinted with a vibration generated by a vibration generator to produce a predetermined tone, and wherein the values ​​of the modified id current component (id) and the modified iq current component (i) stored in the prescribed calibration procedure q ) and / or the altered phase angle of the applied oscillation. This results in the advantages already described and further ones.

[0018] The problem underlying the invention is also solved by a power electronics unit of an electric machine for carrying out the aforementioned method for controlling the electric machine. It is particularly advantageous if the power electronics unit includes a module for carrying out the aforementioned method for calibrating the generated tone or sound, or if such a module is integrated into the power electronics unit. This results in the advantages already described and further advantages.

[0019] The present invention will be further explained below with reference to the drawings.

[0020] They show:

[0021] Figure 1 shows a schematic view of a method according to the invention for controlling an electric machine using indicated power electronics; and

[0022] Figure 2 shows a flowchart of a possible embodiment of a method according to the invention for calibrating a generated tone when controlling the electric machine EM.

[0023] Figures 1 and 2 illustrate a method for calibrating a generated tone when controlling an electric machine EM designed as a three-phase motor. ZF Friedrichshafen AG 215119-DE-NP Friedrichshafen 2025-02-05

[0024] In motor vehicles powered by three-phase motors, acoustics represent a key area of ​​development. Figure 1 schematically illustrates a method for controlling a three-phase motor using power electronics. Based on the acquisition of the id and iq-lst current components during control, a suitable controller type, e.g., a PI controller 4 for the d-axis and a PI controller 5 for the q-axis, adjusts the respective current components so that they approximate the setpoints from the id and iq tables. Due to the necessary transformations in the field-oriented control, the id and iq current components always exhibit time-constant values. Superimposed vibration generators 1 utilize various controlled or regulated methods to induce vibrations in the iq or id current downstream of the actual current controller 2 for the operation of the three-phase motor.This results in a changed current waveform in the control of the three-phase motor. The id and iq current waveforms are therefore no longer constant over time. This allows, for example, more consistent operation of this phase current waveform or, if desired, the encoded frequencies or tones to be audibly reproduced.

[0025] The present invention relates explicitly to the imprinting of a vibration in order to convert it into a tone or sound, such as structure-borne or airborne sound. A method is employed, illustrated in Figure 2, in which a characteristic map is determined, allowing the frequency generation to be pre-controlled in such a way that the generated tone or sound achieves maximum efficiency with respect to the electrical power input and the acoustic power output. This determination is initially carried out empirically but can also be modeled using suitable behavioral models.

[0026] For this purpose, a test tone is generated, as indicated by process step I. Synchronously with the generated test tone, which has a frequency and amplitude, the sound produced by the three-phase motor is evaluated. In a second process step II, a percentage imprint is applied to the id / iq axis regions by changing the id and iq current components. In a third process step III, the percentage distribution of the imprinted vibration on the id and iq current axes is iteratively varied. This distribution ZF Friedrichshafen AG 215119-DE-NP Friedrichshafen 2025-02-05

[0027] The current can assume any value between 100% iq and 100% id. In a fourth process step (IV), the generated tone or sound is recorded and evaluated. In a fifth process step (V), the percentage distribution value id / iq at which the maximum sound or tone is generated is stored. In a sixth process step (VI), a pre-feedback or phase angle of the impressed oscillation relative to the fundamental current wave is iteratively varied. This is intended, in particular, to avoid amplitude amplification in the peak value range of the generated phase currents in order to create voltage reserves in the modulator. For this purpose, in a seventh process step (VII), the peak value of the phase current is first recorded. Here, the phase angle is varied and compared with the peak value of the fundamental oscillation in the time domain. The amplification of the peak value compared to the deactivated oscillation imprinting should be as small as possible.Finally, in an eighth process step (VIII), the determined phase angle at maximum sound and minimum voltage overlay is stored. ZF Friedrichshafen AG 215119-DE-NP Friedrichshafen 2025-02-05.

[0028] Reference mark

[0029] 1 vibration generator

[0030] 2 current regulators of the power electronics

[0031] 3 electric machine

[0032] 4 PI controllers for the d-axis

[0033] 5 PI controllers for the q-axis

[0034] fsoii Setpoint of the frequency of the superimposed oscillation Asoii Setpoint of the amplitude of the superimposed oscillation id id current component

[0035] i q iq power share

[0036] id, son Setpoint of the id current component

[0037] iq.soii setpoint of the iq current component

[0038] id is the actual value of the id current component.

[0039] iq st actual value of the iq current component

[0040] Ad adjusted value of the id current component

[0041] A q adjusted value of the iq current component

[0042] id / iq percentage distribution value of the id and iq current shares

Claims

ZF Friedrichshafen AG 215119-DE-NP Friedrichshafen 2025-02-05 Patent claims 1. Method for calibrating a tone generated by a vibration generator (1) when driving an electric machine (EM) with a phase current with an id current component (id) and an adapted iq current component (i) adjusted by a current controller (2). q ), characterized in that the values ​​of the id current component (id) and the iq current component (i q ) to generate the tone, that the generated tone is evaluated with respect to the generated acoustic power in relation to the electrical power used, and that a distribution ratio of the changed current components (id / iq) in the phase current for generating a tone with maximum acoustic power at minimum electrical power used is stored.

2. Method according to claim 1, characterized in that the stored percentage distribution values ​​of the modified id current components (id) and iq current components (i) are used to calculate q ) a characteristic map is determined.

3. Method according to claim 1 or 2, characterized in that a phase angle of an oscillation imposed on the phase current for controlling the electrical machine (EM) is varied in such a way that an increase in amplitude due to the imposed oscillation in the peak value range of the generated phase current is prevented.

4. Method according to one of the preceding claims, characterized in that, to generate a test tone, the values ​​of the id current component (id) and the iq current component (i) adapted by a current controller (2) are used. q ) are changed so that the values ​​of the id current component (id) and the iq current component (i) q) are varied and the respective generated tone is recorded and evaluated with regard to the generated acoustic power and the respective electrical power input, that a percentage distribution value (id / iq) of the changed current components is stored for a tone with maximum acoustic power at minimum electrical power input, and that peak value ranges of the phase current are recorded and the phase angle of the applied oscillation is changed such that aZF Friedrichshafen AG 215119-DE-NP Friedrichshafen 2025-02-05 The phase angle is stored at maximum acoustic power and minimum electrical voltage surcharge.

5. Method for controlling an electric machine (EM) with a phase current with values ​​of an id current component (id) and an iq current component (i) adapted by a current controller (2). q), wherein a vibration generated by a vibration generator (1) is superimposed on the phase current to generate a predetermined tone, characterized in that the values ​​of a modified id current component (id) and a modified iq current component (i) stored in the calibration method according to one of claims 1 to 4 q ) and / or a changed phase angle of the imposed oscillation.

6. Power electronics of an electric machine (EM) for carrying out a method for controlling the electric machine (EM) according to claim 5.

7. Power electronics according to claim 6, characterized in that a module for carrying out a method according to one of claims 1 to 4 is integrated.

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