Method and arrangement for reducing electromagnetic radiation emanating from an electrical line

Abstract

The invention relates to a method for reducing electromagnetic radiation emanating from an electrical line (14), wherein the electrical line (14) is supplied by at least one first electrical supply line (10) and at least one second electrical supply line (12), comprising at least measuring the currents (50, 52) flowing in the first supply line (10) and in the second supply line (12) using current sensors (20, 22); determining high-frequency current components (60, 62) of the currents (50, 52) of the first and the second supply lines (10, 12); summing the high-frequency current components (60, 62) in an adder (30); supplying an output signal (32) of the adder (30) to a first input (42) of an amplifier (40);Determining a compensation current (56) in the amplifier (40) for a current (54) in the line (14) that keeps the current (54) in the line (14) free of the high-frequency current components (60, 62). The invention further relates to an arrangement (100) for reducing electromagnetic radiation emanating from an electrical line (14).

Description

[0001] The invention relates to a method and an arrangement for reducing electromagnetic radiation emanating from an electrical conductor.

[0002] To achieve electromagnetic compatibility (EMC) standards for power supply lines in a vehicle's passenger compartment, cable harnesses are typically routed within the vehicle to maintain a sufficient distance from the occupants. Alternatively or additionally, costly and complex measures such as ferromagnetic shielding plates or highly permeable films are necessary to reduce the electromagnetic radiation emitted by the cable harnesses. Routing the cable harnesses into the vehicle's underbody to ensure sufficient distance is virtually impossible in later prototype phases due to the complexity involved. Optimizing the electrical components is also difficult and time-consuming to implement.

[0003] From DE 10 2014 205 845 A1, a control device for controlling an electric motor is known, comprising a converter designed to receive a setpoint and output a control variable based on the received setpoint, an output device designed to convert an electrical voltage provided in the electrical network into another voltage, a measuring device designed to acquire measured values ​​in the electrical network, and a detector device designed to detect an interference signal based on the acquired measured values ​​and to output a compensation signal based on the detected interference signal, wherein the output device is designed to convert the electrical voltage in the electrical network into another voltage using the control variable output by the converter and the compensation signal output by the detector device.

[0004] From DE 10 2016 110 596 A1, an active interference suppression device for reducing the interference effect of an interference source at a single interference sink is known, comprising a sensor configured to detect an interference quantity from an interference source of at least one electrical line, the interference to be reduced at an interference sink; a compensation device for generating a compensation quantity, comprising an amplifier configured to adjust the amplitude of the interference quantity detected by the sensor with respect to the interference effect of the interference quantity at the interference sink, so that the interference effect at the interference sink is reduced; and / or a phase shifter configured to adjust the phase of the interference quantity detected by the sensor with respect to the interference effect of the interference quantity at the interference sink, so that the interference effect at the interference sink is reduced.wherein the compensation quantity comprises the disturbance quantity adapted by the amplifier and the disturbance quantity adapted by the phase shifter, and a coupling device configured to couple the compensation quantity into the at least one line and / or the disturbance sink.

[0005] From DE 199 40 284 C1, a device for compensating an electric and / or magnetic field generated by electrical disturbances acting in one or more electrical interference conductors is known, comprising one or more electrical compensation conductors arranged along the interference conductor(s) and connected to a compensation circuit. The compensation circuit includes means for detecting the disturbances acting in the interference conductor(s) and switching means for generating compensation quantities acting in the compensation conductor(s) depending on the detected disturbances.

[0006] From DE 10 2016 205 338 A1, a circuit arrangement is known comprising a control device, an electrical load, and an electrical supply line via which the control device is connected to the load for transmitting electrical power, wherein the control device is configured to generate an electrical supply voltage provided in the supply line for controlling the transmitted electrical power and thereby to set a temporal profile of the supply voltage, wherein an electrical compensation line is arranged next to the supply line, wherein a first, device-side line end is connected to the control device and a second, load-side line end is open to the load, and wherein the control device has a mirror circuit which is configured toto generate in the compensation line a voltage profile that mirrors the time profile of the supply voltage in such a way that the sum of the profile of the supply voltage in the supply line and the voltage profile in the compensation line lies within a predetermined tolerance interval and, in particular, is constant.

[0007] From EP 2 787 619 A1, a device for electromagnetic interference (EMI) filtering is known, comprising a noise detection circuit for receiving EMI noise occurring at a noise source, an active feedforward circuit that is operationally coupled to the noise detection circuit to generate a noise suppression signal based on EMI noise received by the noise detection circuit, and a filter that is operationally coupled to the active feedforward circuit and the noise source and is adapted to receive the EMI noise occurring at the noise source and the noise suppression signal from the active feedforward circuit, wherein the filter suppresses received EMI noise based on the received noise suppression signal in order to reduce the EMI noise at a consumer.

[0008] One object of the invention is to provide an efficient method for reducing electromagnetic radiation emanating from an electrical conductor.

[0009] Another object of the invention is to create an arrangement for reducing electromagnetic radiation emanating from an electrical conductor using such an efficient method.

[0010] The aforementioned tasks are solved using the characteristics of independent claims.

[0011] Favorable embodiments and advantages of the invention will become apparent from the further claims, the description and the drawing.

[0012] According to one aspect of the invention, a method for reducing electromagnetic radiation emanating from an electrical line is proposed, wherein the electrical line is supplied by at least one first electrical supply line and at least one second electrical supply line, wherein the line is coupled to the at least one first and the at least one second supply line at a node, comprising at least: Measuring the currents flowing in the first and second supply lines using current sensors; determining high-frequency current components of the currents in the first and second supply lines; summing the high-frequency current components in an adder; feeding an output signal of the adder to a first input of an amplifier; determining a compensation current in the amplifier for a current in the line, which keeps the current in the line free of the high-frequency current components of the first and second supply lines; applying the compensation current flowing from the node via the amplifier to the current storage device to a current storage device coupled to an output of the amplifier.

[0013] The proposed method actively reduces electromagnetic radiation emanating from wiring harnesses into the passenger compartment of a vehicle. It proposes using current sensors to measure high-frequency current components in the power supply lines and actively filtering these out with a fast amplifier. This improves the electromagnetic compatibility (EMC) in the vehicle's interior.

[0014] This method allows the EMC-relevant frequencies to be filtered out. The current flowing in the combined line of the two supply lines then contains a current in which these frequencies are filtered out.

[0015] The supply lines and the cable can be either individual lines or entire cable harnesses.

[0016] According to the proposed method, the currents of the two supply lines are first determined. Current sensors measure the relevant high-frequency components of the currents. Direct current components are filtered out.

[0017] The high-frequency current components from the current sensors are fed to the adder. The adder sums these up.

[0018] The output signal of the adder, i.e., the sum of the high-frequency components from the current sensors, is fed to the amplifier as an input signal. From this, the compensation current is calculated, which must flow from the node of the supply lines to the line in order to perform the active filtering.

[0019] The energy storage device is supplied with this compensation current via the amplifier.

[0020] The proposed method can be advantageously carried out for cable harnesses in the low voltage range, e.g. 12V, 48V or a maximum of 60V.

[0021] According to an advantageous embodiment of the method, the currents flowing in the first and second supply lines can be measured using current shunts, each coupled to two analog-to-digital inputs of a microcontroller, or using inductive current sensors. In particular, an analog bandwidth of at least 10 Hz to 4 MHz can be used. For this purpose, an analog-to-digital input of a microcontroller with a clock frequency of at least 4 MHz can be used. Examples of inductive current sensors include Rogowski coils, current transformers, and inductors.

[0022] According to an advantageous embodiment of the method, the summation of the high-frequency current components and / or the determination of the adder's output signal and / or the determination of the compensation current can be performed as program code in a microcontroller. The adder and amplifier can thus be advantageously designed as components of a microcontroller whose functions are implemented as program code.

[0023] Alternatively, the summation of the high-frequency current components and / or the determination of the adder's output signal and / or the determination of the compensation current can be performed in an analog circuit. This method advantageously allows for high bandwidths.

[0024] According to an advantageous embodiment of the method, the current measurement, and / or the summation of the high-frequency current components, and / or the determination of the compensation current can be performed in an ASIC. This allows for application-specific and cost-optimized design of the components required for the method.

[0025] According to an advantageous embodiment of the method, a power semiconductor, in particular a MOSFET, or a DC / DC converter can be used as the amplifier. In particular, the switching frequency of the amplifier can be at least ten times higher than the highest frequency to be filtered. This allows for effective filtering of the high-frequency current components, resulting in reduced currents in the frequency range relevant for EMC (electromagnetic compatibility) within the cable harness to be filtered.

[0026] According to an advantageous embodiment of the method, a supercapacitor or a battery can be used as the energy storage device. Supercapacitors, also known as supercaps, can be charged and discharged with very high currents in a short time and are therefore well suited for energy storage in the high-frequency range. The compensation current that charges the energy storage device is an alternating current in the range of 10 Hz to 400 kHz.

[0027] According to an advantageous embodiment of the method, the compensation current can be a negative sum of the currents flowing in the first supply line and the second supply line. The conversion to determine the compensation current takes place in the amplifier. The aim of the compensation is to ensure that the resulting current in the line to be filtered contains as few current components as possible in the frequency range of 10 Hz to 400 kHz and thus does not generate any EMC-relevant magnetic fields.

[0028] According to an advantageous embodiment of the method, an alternating current, particularly in a frequency range between 10 Hz and 400 kHz, can be used as the compensation current. This allows the current through the line to be filtered to be effectively filtered, so that the current no longer contains any high-frequency components.

[0029] According to an advantageous embodiment of the method, the energy storage device can be discharged, at least temporarily, via the amplifier using direct current. The compensation current is an alternating current in the range of 10 Hz to 400 kHz. Therefore, the energy storage device does not typically reach full charge. If necessary, however, the energy storage device can be selectively discharged via direct current, for example, using an additional function of the DC / DC converter employed as an amplifier.

[0030] According to a further aspect of the invention, an arrangement for reducing electromagnetic radiation emanating from an electrical conductor is proposed using such a method, wherein the electrical conductor is supplied by at least one first electrical supply line and at least one second electrical supply line, wherein the conductor is coupled to the at least one first and the at least one second supply line at a node, comprising at least current sensors arranged in the first supply line and in the second supply line for determining high-frequency current components of the currents of the first and the second supply line, an adder coupled to the current sensors for summing the high-frequency current components, and an amplifier whose input is coupled to an output of the adder, which is configured as follows:to determine a compensation current for a current in the line, which keeps the current in the line free from the high-frequency current components of the first and second supply lines, as well as a current storage device which is coupled to an output of the amplifier.

[0031] The proposed arrangement serves to actively reduce electromagnetic radiation emanating from wiring harnesses into the passenger compartment of a vehicle. It is proposed to use current sensors to measure high-frequency current components in the supply lines and to actively filter these out using a fast amplifier. This improves the electromagnetic compatibility (EMC) in the vehicle's interior.

[0032] This arrangement allows the EMC-relevant frequencies to be filtered out. The current flowing in the combined conductor of the two supply lines then carries these filtered-out frequencies.

[0033] The supply lines and the cable can be either individual lines or entire cable harnesses.

[0034] In the proposed setup, the currents of the two supply lines are first determined. Current sensors measure the relevant high-frequency components of the currents. Direct current components are filtered out.

[0035] The high-frequency current components from the current sensors are fed to the adder. The adder sums these up.

[0036] The output signal of the adder, i.e., the sum of the high-frequency components from the current sensors, is fed to the amplifier as an input signal. From this, the compensation current is calculated, which must flow from the node of the supply lines to the line in order to perform the active filtering.

[0037] The energy storage device is supplied with this compensation current via the amplifier.

[0038] The proposed arrangement can be advantageously used for cable harnesses in the low voltage range, e.g. 12V, 48V or a maximum of 60V.

[0039] Advantageously, current sensors for measuring the currents flowing in the first and second supply lines can be current shunts, each coupled to two analog-to-digital inputs of a microcontroller, or inductive current sensors. In particular, an analog bandwidth of at least 10 Hz to 4 MHz can be used. For this purpose, an analog-to-digital input of a microcontroller with a clock frequency of at least 4 MHz can be used. Examples of inductive current sensors include Rogowski coils, current transformers, and inductors.

[0040] Adders and amplifiers can be advantageously integrated into a microcontroller whose functions are implemented as program code. Conveniently, the summing of the high-frequency current components, the determination of the adder's output signal, and / or the determination of the compensation current can thus be performed as program code within the microcontroller.

[0041] Alternatively, adders and amplifiers can also be implemented as analog circuits. This allows for the advantageous achievement of high bandwidths.

[0042] Adders and amplifiers can be advantageously implemented as ASICs. Current measurement, and / or summation of the high-frequency current components, and / or determination of the compensation current can all be performed within the ASIC. This allows for application-specific and cost-optimized design of the components required for the process.

[0043] Advantageously, the amplifier can be a power semiconductor, particularly a MOSFET, or a DC / DC converter. In particular, the amplifier's switching frequency can be at least ten times higher than the highest frequency to be filtered. This allows for effective filtering of the high-frequency current components, resulting in reduced currents in the filtered cable harness within the frequency range relevant for EMC (electromagnetic compatibility).

[0044] A supercapacitor or a battery can be advantageously used as the energy storage device. Supercapacitors, also known as supercaps, can be charged and discharged with very high currents in a short time and are therefore well-suited for energy storage in the high-frequency range. The compensation current that charges the energy storage device is an alternating current in the range of 10 Hz to 400 kHz.

[0045] Advantageously, the compensation current can be a negative sum of the currents flowing in the first and second supply lines. The conversion to determine the compensation current takes place in the amplifier. The goal of the compensation is to ensure that the resulting current in the line to be filtered contains as few current components as possible in the frequency range of 10 Hz to 400 kHz, and thus does not generate any EMC-relevant magnetic fields.

[0046] Advantageously, the compensation current can be an alternating current, particularly in a frequency range between 10 Hz and 400 kHz. This allows the current to be effectively filtered through the line to be filtered, so that the current no longer contains high-frequency components.

[0047] Advantageously, the energy storage device can be designed to be discharged, at least temporarily, via the amplifier using direct current. The compensation current is an alternating current in the range of 10 Hz to 400 kHz. Therefore, the energy storage device does not typically reach full capacity. If necessary, however, the energy storage device can be selectively discharged via direct current, for example, using an additional function of the DC / DC converter employed as an amplifier.

[0048] Further advantages will become apparent from the following description of the drawing. The drawing illustrates an embodiment of the invention. The drawing, the description, and the claims contain numerous features in combination. A person skilled in the art will expediently consider the features individually and combine them into meaningful further combinations.

[0049] This shows: Fig. 1 An arrangement for carrying out the method for reducing electromagnetic radiation emanating from an electrical conductor according to an embodiment of the invention.

[0050] In the figures, identical or similar components are numbered with the same reference symbols. The figures merely show examples and are not to be understood as limiting.

[0051] Fig. Figure 1 shows an arrangement 100 for carrying out the method for reducing electromagnetic radiation emanating from an electrical line 14 according to an embodiment of the invention.

[0052] The electrical line 14 is supplied by at least one first electrical supply line 10 and at least one second electrical supply line 12. The line 14 is coupled to the at least one first and the at least one second supply line 10, 12 at a node 16. The currents 50, 52 of the two supply lines 10, 12 are split at the node 16 into the current 54 in line 14 and the current 56, which flows via a amplifier 40.

[0053] Supply lines 10, 12 and line 14 can be either individual lines or entire cable harness sections.

[0054] The arrangement 100 has current sensors 20 and 22 in the supply lines 10 and 12, respectively, which are coupled to an adder 30. The output 32 of the adder 30 goes to an input 41 of the amplifier 40. A second input 42 of the amplifier 40 is coupled to node 16.

[0055] One output 43 of the amplifier 40 is connected to ground. Another output 44 is coupled to a power storage device 46, the other pole of which is also connected to ground.

[0056] According to the proposed procedure, the currents 50, 52 flowing in the first supply line 10 and in the second supply line 12 are measured by means of the current sensors 20, 22.

[0057] High-frequency current components 60, 62 of the currents 50, 52 of the first and second supply lines 10, 12 are determined and summed in the adder 30.

[0058] The output signal 32 of the adder 30 is fed to the first input 41 of the amplifier 40, which thereby determines a compensation current 56 for the current 54 in the line 14, which keeps the current 54 in the line 14 free from the high-frequency current components 60, 62 of the first and the second supply lines 10, 12.

[0059] The power storage device 46 is then supplied with the compensation current 56 flowing from the node 16 via the amplifier 40 to the power storage device 46.

[0060] In this way, the current 54 flowing in line 14 can be filtered out from the high-frequency current components 60, 62.

[0061] As compensation current 56, an alternating current, especially in a frequency range between 10 Hz and 400 kHz, can be used to meet the EMC-relevant requirements.

[0062] The currents 50, 52 flowing in the first supply line 10 and the second supply line 12 can be measured, for example, using current shunts coupled to two analog-to-digital inputs of a microcontroller, or using inductive current sensors. An analog bandwidth of at least 10 Hz to 4 MHz can be advantageously used for this purpose. An analog-to-digital input of a microcontroller with a clock frequency of at least 4 MHz can be used for this. Rogowski coils, current transformers, and inductors, for example, can be used as inductive current sensors 20, 22.

[0063] For example, a power semiconductor, in particular a MOSFET, or preferably a DC / DC converter, can be used as the amplifier 40. In this way, the compensation current 56 can be fed into the current storage device 46 by voltage conversion, so that the cable harness 14 to be filtered exhibits reduced currents 54 in the frequency range relevant for EMC.

[0064] The amplifier 40, especially the DC / DC converter, can advantageously be at least ten times faster than the highest frequency to be filtered.

[0065] The energy storage device 46 can be, for example, a supercapacitor or a battery. If the energy storage device 46 is fully charged, it can be discharged, at least temporarily, via the amplifier 40 using direct current.

[0066] Advantageously, the compensation current 56 can be chosen to be a negative sum of the currents 50 and 52 flowing in the first supply line 10 and the second supply line 12, respectively. The conversion to determine the compensation current 56 takes place in the amplifier 40. The aim of the compensation is that the resulting current 54 in the line 14 to be filtered contains as few current components as possible in the frequency range of 10 Hz to 400 kHz and thus does not generate any EMC-relevant magnetic fields.

[0067] The addition, corrections, and calculation of the required output signal as compensation current 56 can, for example, be performed as program code in a microcontroller. Alternatively, the functions can also be implemented entirely analogously, which is more complex and less flexible. With an application-specific and cost-optimized design, current measurement, addition, and calculation of the compensation current can also be performed in an ASIC. Reference symbol list 10 first supply line 12 second supply line 14 Management 16 knots 20 Current sensor 22 Current sensor 30 Adders Exit 31 32 Output signal 40 amplifiers Entrance 41 42 Entrance Exit 43 44 Exit 46 Energy storage 50 Electricity in the first supply line 52 Electricity in the second supply line 54 Current in the line 56 Compensation current 60 high-frequency current component 62 high-frequency current component 100 arrangement

Claims

[1] Method for reducing electromagnetic radiation emanating from an electrical line (14), wherein the electrical line (14) is supplied by at least one first electrical supply line (10) and at least one second electrical supply line (12), wherein the line (14) is coupled to the at least one first and the at least one second supply line (10, 12) at a node (16), comprising at least Measuring the currents (50, 52) flowing in the first supply line (10) and in the second supply line (12) using current sensors (20, 22); Determining high-frequency current components (60, 62) of the currents (50, 52) of the first and second supply lines (10, 12); Summing the high-frequency current components (60, 62) in an adder (30); supplying an output signal (32) of the adder (30) to a first input (42) of an amplifier (40); Determining a compensation current (56) in the amplifier (40) for a current (54) in the line (14) which keeps the current (54) in the line (14) free from the high-frequency current components (60, 62) of the first and second supply lines (10, 12); Applying the compensation current (56) flowing from the node (16) via the amplifier (40) to the power storage device (46) coupled to an output (44) of the amplifier (40). [2] Method according to claim 1, wherein the currents (50, 52) flowing in the first supply line (10) and in the second supply line (12) are measured by means of current shunts which are coupled to two analog-digital inputs of a microcontroller or by means of inductive current sensors, in particular wherein an analog bandwidth of at least 10 Hz to 4 MHz is used. [3] Method according to claim 1 or 2, wherein the summation of the high-frequency current components (60, 62) and / or the determination of the output signal (32) of the adder (30) and / or the determination of the compensation current (56) is performed as program code in a microcontroller or in an analog circuit. [4] Method according to one of the preceding claims, wherein the current measurement, and / or the summation of the high-frequency current components (60, 62) and / or the determination of the compensation current (56) is carried out in an ASIC. [5] Method according to one of the preceding claims, wherein a power semiconductor, in particular a MOSFET, or a DC / DC converter is used as the amplifier (40), in particular wherein a switching frequency of the amplifier (40) is at least ten times higher than a highest frequency to be filtered. [6] Method according to one of the preceding claims, wherein a supercapacitor or a battery is used as the energy storage device (46). [7] Method according to one of the preceding claims, wherein the compensation current (56) is selected to be a negative sum of the currents (50, 52) flowing in the first supply line (10) and in the second supply line (12). [8] Method according to one of the preceding claims, wherein the compensation current (56) is an alternating current, in particular in a frequency range between 10 Hz and 400 kHz. [9] Method according to one of the preceding claims, wherein the energy storage device (46) is discharged via the amplifier (40) by direct current, at least temporarily. [10] Arrangement (100) for reducing electromagnetic radiation emanating from an electrical line (14) using a method according to one of the preceding claims, wherein the electrical line (14) is supplied by at least one first electrical supply line (10) and at least one second electrical supply line (12), wherein the line (14) is coupled to the at least one first and the at least one second supply line (10, 12) at a node (16), at least comprising Current sensors (20, 22) arranged in the first supply line (10) and in the second supply line (12) for determining high-frequency current components (60, 62) of the currents (50, 52) of the first and second supply lines (10, 12), an adder (30) coupled to the current sensors (20, 22) for summing the high-frequency current components (60, 62), an amplifier (40) whose input (41) is coupled to an output (31) of the adder (30), which is configured to determine a compensation current (56) for a current (54) in the line (14) that keeps the current (54) in the line (14) free from the high-frequency current components (60, 62) of the first and second supply lines (10, 12), a power storage device (46) which is coupled to an output (44) of the amplifier (40).

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