DEVICE FOR DAMPING MECHANICAL VIBRATIONS IN ELECTRICAL CONDITIONERS CARRYING MODULATED CURVES

Description

Area

[0001] The invention relates to the damping of mechanical vibrations in electrical cables, in particular electrical supply lines to drive components of electric and hybrid vehicles. background

[0002] Electrical currents in drive components of electric and hybrid vehicles, such as motors and batteries, are typically controlled by power electronics. This typically involves modulated, e.g., pulsed control, such as pulse-width modulation, to minimize electrical losses while still achieving good power control.

[0003] The power converted into drive components of electric and hybrid vehicles is often in the high double-digit or even triple-digit kilowatt range, so that even at high voltages of 400 V or even 800 V, currents of over 100 A still flow. These currents generate a magnetic field in electrical cables, which in turn creates a force acting on them. High modulated, particularly pulsed currents generate a magnetic field generated at the frequency of the modulation, with a correspondingly acting force. Electrical cables in electric and hybrid vehicles are laid in or along body parts and fixed there at specific intervals. A force acting on the electrical cable can move it, particularly between the fixing points. A pulse-like force can therefore move the electrical cable in a pulse-like manner.If the electrical currents flowing through the cable have a corresponding frequency, airborne and / or structure-borne sound can cause vibrations in the frequency range that can be acoustically perceived by humans.

[0004] US 5,427,102 A1 discloses active noise suppression in a magnetic resonance imaging (MRI) device. In the MRI device, pulsating currents in a gradient magnetic field coil create vibrations caused by magnetic forces, producing loud noises that are unpleasant for the patient being examined. To suppress or reduce the noise, an acoustic signal is generated with a sound generator, or the gradient magnetic field coil is set into vibrations that counteract the noise-generating vibrations of the gradient magnetic field coil.

[0005] US 2021 / 0082388 A1 discloses a device and method for noise suppression in a vehicle. For this purpose, interior loudspeakers are provided inside the vehicle. These loudspeakers generate an acoustic field, thereby suppressing noise in the interior. Furthermore, actuators ("shakers") are provided that generate vibrations that prevent or at least reduce vibration-acoustic effects.

[0006] Based on this, the present invention has the object of creating a device and a method for damping oscillations in electrical conductors through which modulated currents flow. Summary of the invention

[0007] This object is achieved by the device specified in claim 1 and the method specified in claim 6. Advantageous embodiments and further developments are described in the respective dependent claims.

[0008] A device according to claim 1 according to a first aspect of the invention comprises at least one sound or vibration sensor directed towards the line or attached to the line, at least one actuator connected to the line, and a control circuit. The control circuit can have a microprocessor, volatile and non-volatile memory connected thereto, one or more microphone inputs connected to sound or vibration sensors, and one or more control outputs connected to actuators. Signals representing sound or vibrations generated by the at least one sound or vibration sensor are supplied to the control circuit via respective signal lines. The control circuit controls the at least one actuator via respective control lines such that it counteracts the vibration of the line.

[0009] The at least one actuator can, for example, comprise an electromagnetic or piezoelectric drive, which is controlled by the control circuit in such a way that it generates a force that counteracts the force generated by the current flow. The at least one actuator is preferably mounted on a structure on or in which the cable is laid in such a way that vibrations originating from the actuator or introduced into the structure are only transmitted in a damped manner or are first eliminated. The actuator can, for example, be mounted in an elastically damping element.

[0010] According to the invention, the at least one sound or vibration sensor enables spatial resolution of the vibration amplitude along at least a portion of the line. The control circuit is configured to control the at least one actuator such that the maximum vibration amplitude is reduced at a location along the portion of the line detected by the sound or vibration sensor. The actuator is controlled by the control circuit such that the reduction in the vibration of the line does not necessarily occur at the location where the actuator acts on the line.Rather, the actuator itself can introduce a vibration into the cable, which, through destructive interference, disrupts a vibration generated by the current flowing in the cable, thus resulting in an overall smaller vibration amplitude, or it can create a shift in the frequency of the vibration, which is perceived as less disturbing or is dampened by other design measures. This design takes into account the fact that an actuator cannot always be installed at a point on the cable that is particularly susceptible to vibration.

[0011] According to the invention, the sound or vibration sensor is an optical microphone. Optical microphones can detect changes in the optical refractive index within a vibrating medium, which are caused by local density changes generated by vibrations. Depending on the medium, the largest amplitude can also be localized along the measurement path, e.g., in an optical fiber using time-domain reflectometry (TDR).

[0012] In one or more embodiments, a signal is supplied to the control circuit that represents information about the modulation, e.g., the pulse frequency, the pulse duration, and the current intensity of the electrical current flowing in the line. Such a signal can be transmitted, for example, by a control device that regulates the current in the line. The control circuit uses this information to excite the at least one actuator with a frequency and / or phase that counteracts the vibration induced by the current. In these embodiments, the requirements for the sound or vibration sensor with regard to sensitivity or frequency resolution can be lower.Furthermore, in these embodiments the control circuit can control the at least one actuator with a frequency sweep during a learning phase, i.e. with an alternating signal whose frequency continuously runs through a predetermined range, and can use the at least one sound or vibration sensor to record the amplitude and frequency of the acoustically perceptible sound caused by the vibrations in the line. In this case, a correlation can be established between the amplitude of the perceptible sound and the underlying current in the line. In this way, even without a precise measurement, the at least one actuator can be controlled with a suitable control signal as soon as a current is applied to the line. Measurements of the sound or the vibrations in the line can then be used to detect changes in the vibrations in the line with otherwise identical currents, identical modulation, etc., as can occur, for example, in the case ofcaused by temperature- or aging-related changes in the materials or dirt deposits on the cable. Based on these measurements, the correlation can then be adjusted or expanded, for example, to include temperature. Thus, using information from a thermometer, e.g., an outside thermometer in a motor vehicle, and the signal transmitted by the control device, a suitable control signal for at least one actuator can be used right at the start of use.

[0013] The device can be used in particular in electric and hybrid vehicles to dampen vibrations in electrical cables caused by the drive control.

[0014] A method according to claim 6 according to a second aspect of the invention comprises detecting, in a control circuit, vibrations of a line through which a modulated electrical current flows using at least one sound or vibration sensor. Based on the detected vibrations of the line, the control circuit generates and outputs control signals for at least one actuator with the aim of damping the vibrations of the line. The method can be executed continuously in a closed control loop.

[0015] In one or more embodiments of the method, the control circuit receives a signal that provides information about a current intensity and a modulation of the current flowing in the line. Based on this information, the control circuit selects a control signal for the at least one actuator from a correlation table and outputs it. This can also be repeated in a continuous control loop.

[0016] In one or more embodiments, the method comprises, in a learning phase, receiving a signal that provides information about a current intensity and a modulation of the current flowing in the line. The control circuit applies a frequency sweep to at least one actuator and detects the oscillations of the line. The frequency sweep and the detection of the oscillation are repeated, if necessary, with a modified amplitude of the control signal. From the characteristic map thus obtained, a control signal is determined that maximally dampens the oscillations of the line, and the determined signal is stored in a correlation table together with the associated current in the line and its modulation.

[0017] A computer program product according to a further aspect of the invention contains program instructions which, when executed by a processor of a control circuit connected to at least one sound or vibration sensor and at least one actuator, cause the control circuit to carry out one or more embodiments and further developments of the method described above.

[0018] The computer program product can be stored on a computer-readable medium or data carrier. The medium or data carrier can be physically embodied, e.g., as a hard drive, CD, DVD, flash memory, or the like, but the medium or data carrier can also comprise a modulated electrical, electromagnetic, or optical signal that can be received by a computer via a corresponding receiver and stored in the computer's memory. Short description of the drawing

[0019] The invention will be explained in more detail below using an exemplary embodiment with reference to the accompanying figures. All figures are purely schematic and not to scale. They show: Fig. 1 is a schematic representation of an exemplary device for damping oscillations in electrical lines through which modulated currents flow, Fig. 2 is a flow diagram of an embodiment of the method according to the invention, and Fig. 3 is an exemplary block diagram of a control circuit configured to carry out one or more aspects of the method according to the invention.

[0020] Identical or similar elements may be provided with identical or similar reference numerals in the figures. Example

[0021] Figure 1shows a schematic representation of an exemplary device 100 for damping oscillations in electrical lines 10 through which modulated currents flow. In the Figure 1In the example shown, the line 10 is connected to a structure not shown in the figure at two fixing points 106. Between the fixing points 106, the line can change its position, in particular oscillate transversely to its longitudinal extent. A modulated current flows through the line 10, indicated in the figure by the square wave. The modulated current leads to electromagnetic forces that act on the line and can cause it to oscillate. Depending on the frequency and strength of the modulated current, the line 10 can oscillate more or less strongly between the fixing points 106, generating an audible sound. It is also possible for the line to strike the structure at the frequency of the oscillation.The device 100, formed in the figure by the components arranged within the dashed border, comprises at least one sound or vibration sensor 102, which records vibrations or sound emanating from a line 10 and applies a corresponding signal to a control circuit 200. The control circuit 200 analyzes the signal(s) applied by the one or more sound or vibration sensors and applies a control signal to one or more actuators 104, each of which exerts a corresponding force acting on the line 10, counteracting the vibration of the line 10. The control circuit 200 is also supplied with a signal S, which is output by a control device (not shown in the figure) that modulates the current through the line 10 and transmits information about the current intensity and the modulation of the current.

[0022] Figure 2shows a flowchart of an embodiment of the method 300 according to the invention. In step 302, vibrations of the line 10 are detected using at least one sound or vibration sensor. In step 304, control signals for at least one actuator 104 are generated, which are output in step 306.

[0023] Additionally, in an optional step 308, a signal S can be received, which provides information about a current intensity and a modulation of the current flowing in line 10. Based on the signal S, control signals for at least one actuator are selected from a correlation table in step 310 and additionally used as the basis for the generation in step 304. This allows a suitable control signal to be applied to at least one actuator as early as the beginning of the modulated current flow, so that the line's oscillation can be damped more quickly. Continuous control can still be performed.

[0024] The correlation table can be populated with data during a learning phase. For this purpose, starting from step 308, a frequency sweep can be applied to at least one actuator in step 312, while vibrations of the line are detected in step 314. The frequency sweep can be repeated with a modified amplitude of the control signal of the at least one actuator. In step 316, a control signal is determined from the previously generated characteristic map, which maximally dampens the vibrations of line 10. This control signal is stored in the correlation table in step 318 and is available for selection in step 310.

[0025] Figure 3shows an exemplary block diagram of a control circuit 200 configured to carry out one or more aspects of the method according to the invention. Control circuit 200 includes, in addition to a microprocessor 202, volatile and non-volatile memory 204 and 206, respectively, at least one control output 208, at least one microphone input 210, and optionally at least one signal input 212. The components of control circuit 200 are communicatively connected to one another via one or more data connections or buses 214. Non-volatile memory 206 contains computer program instructions which, when executed by microprocessor 202, configure control circuit 200 of device 100 to carry out method 300 according to the invention. List of reference symbols

[0026] 10 Line 214 Data connection / bus 100 device 300 Proceedings 102 Sound / vibration sensors 302 Capture 304 Generate 104 Actuator 306 Spend 106 Fixation point 308 Received 200 Control circuit 310 Choose 202 microprocessor 312 Invest 204 volatile memory 314 Capture 206 non-volatile memory 316 Determine 208 Control output 318 Save 210 Microphone input S signal 212 Signal input

Claims

1. A device (100) for damping mechanical vibrations in electric lines (10) through which modulated currents flow comprising at least one sound or vibration sensor (102) aligned towards line (10) or fastened to the line, at least one actuator (104) connected to the line and a control circuit (106), to which signals representing sound or vibrations generated by the at least one sound or vibration sensor (102) are fed via respective signal lines (108), and which actuates the at least one actuator (104) via respective control lines (110) so that said actuator counteracts the vibration of the line (10), characterized in that the at least one sound or vibration sensor (102) comprises an optical microphone, which enables a local resolution of the vibration amplitude along at least one part of the line (10), and that the control circuit (106) is set up to actuate the at least one actuator (104) so that the maximum vibration amplitude is reduced.

2. The device (100) according to claim 1, wherein the at least one actuator (104) has an electromagnetic or piezoelectric drive.

3. The device (100) according to claim 1 or 2, wherein the at least one actuator (104) is attached to a structure, on or in which the line is laid, so that vibrations emanating from the actuator (104) or introduced into the latter are only introduced into the structure in damped form or are extinguished beforehand.

4. The device (100) according to any one of the preceding claims, wherein a signal is fed to the control circuit (106, which represents information about the pulse frequency, the pulse duration and / or the current strength of the electric current flowing in the line (10), and wherein the control circuit (106) is set up to excite a respective actuator (104) with a frequency and / or phase on the basis of the signal, which counteracts the vibration caused by the current.

5. The device (100) according to claim 4, wherein the control circuit (106) is set up to actuate the at least one actuator (104) in a learning phase with a frequency sweep, and to form a correlation from the signal representing information about the current flowing in the line (10) and the amplitude and frequency of the vibration of the line (10) recorded by the at least one sound or vibration sensor (102), which for a certain pulse frequency, amplitude and / or pulse duration contains an actuation signal for the at least one actuator (104), which causes a damping of the vibration of the line (10).

6. A method (300) for damping vibrations in electric lines (10) through which modulated currents flow by means of a device (100) according to any one claims 1 to 5, comprising: - locally resolved detection (302) of vibrations of the line (10) by means of at least one sound or vibration sensor (102), - generating (304) control signals for at least one actuator (104), and - outputting (306) the control signals.

7. The method (300) according to claim 6, also comprising: - receiving (308) a signal (S), which provides information about a current strength and a modulation of the current flowing in the line (10), - selecting (310) control signals for at lest one actuator (104) from a correlation table, - generating (304) control signals for at least one actuator (104), and - outputting (306) the control signals.

8. The method (300) according to claim 6 or 7, also comprising, in a learning phase: - receiving (308) a signal (S), which provides information about a current strength and a modulation of the current flowing in the line (10), - applying (312) a frequency sweep to at least one actuator (104), - detecting (314) vibrations of line (10) by means of the at least one sound or vibration sensor (102), - repeating the frequency sweep with a changed amplitude of the control signal of the at least one actuator, - determining (316) a control signal, in which the vibrations of line (10) are maximally damped, and - saving (318) the control signal and the current strength and modulation of the current in a correlation table.

9. A computer program product comprising program instructions which, when the program is executed by a microprocessor (202) of a control circuit (200) of a device (100) according to any one of claims 1 to 5, cause the method according to one or more of claims 6 to 8 to be executed.

10. A computer-readable medium, on which the computer program product according to claim 9 is saved.

11. An electric or hybrid vehicle with a device according to any one of claims 1 to 5.