Magnetic Field Cancellation System

Abstract

A method and system for use in reducing magnetic fields generated by an electrical system includes determining one or more current-carrying loops in electrical wiring of an electrical system, providing a parallel wire loop to at least one of the one or more current-carrying loops generally overlapping a physical path of the at least one current-carrying loop, connecting the parallel wire loops to a power system having at least one sensor, operating the at least one current sensor to provide sensed data indicative of a current passing through the at least one current-carrying loop, and operating the power system based on the sensed data to transmit a current through the parallel wire loop in a direction opposite to the current passing through the at least one current-carrying loop, thereby eliminating a magnetic field generated by the current passing through the current-carrying loop.

Description

[Technical field]

[0001] SYSTEMS AND METHODS FOR CANCELLING MAGNETIC FIELD This disclosure relates to systems and methods for cancelling magnetic fields in selected areas, and more particularly to cancelling magnetic fields in the vicinity of electrical systems such as hybrid and electric vehicles. [Background technology]

[0002] Electromagnetic radiation and electromagnetic fields in general surrounding the human environment are increasing with the use of electrical appliances. In various situations and applications, the ability to neutralize or significantly reduce the electromagnetic fields (EMF) and electromagnetic radiation in a specific area may be required. A particular such situation concerns electric and hybrid vehicles. Such electric and hybrid vehicles utilize electric currents to run the motors and other systems, while the occupants may spend a significant amount of time inside the vehicle exposed to electromagnetic waves.

[0003] Medical studies have shown that low frequency electromagnetic radiation is believed to cause long term adverse health effects. In the case of electric cars and other motorized vehicles, it may be desirable to reduce the radiation of electromagnetic fields in the area of ​​the passenger seats. Summary of the Invention

[0004] Electrical systems commonly employ the transmission of electric current from a source to a consumer or load. Electric current is typically transmitted through wires that extend into space between the source and the load. The flow of current in such a wire generates a magnetic field, based on Ampere's circular law, whose differential equation is ∇×B=μ0J, where B is the magnetic field, ∇× is the curl differential operator, μ0 is the permeability of free space, and J is the density of the electric current.

[0005] To properly transfer electricity, the transmission line between the power source and the load creates a closed circuit. A transmission line / power line has two or more separate wires / wires, each connected to the positive and negative (or phase and zero) contacts of the power source, to transfer the current to the load and back to the power source. Thus, although the electrical connection between the power source and the load may also include a positive and negative potential or a phase and zero / ground connection, this specification utilizes at least a pair of electrical wires as the power and zero wires. Furthermore, as will be described in more detail below, in some configurations, only a single power wire may be used to transfer the potential to the load. In these configurations, the load is typically connected to a valid ground contact, providing a "zero" wire that passes through a conductive element, such as a chassis component of a vehicle.

[0006] To avoid the generation of magnetic fields, the wires of a pair are typically twisted between them along a path between the physical location of the power source and the location of the load. However, physical and mechanical constraints in the wire arrangement and / or electrical connection of the load may cause the twisted wires of the pair to separate at certain points, resulting in different (e.g., positive and negative) wires following different paths. This results in an effective current-carrying loop that extends from the branch of the twisted pair of wires along the positive wire portion through the current path in the load to the respective connection point of the load, and from the respective second connection point of the load through the negative wire portion to the branch of the twisted pair of wires. The transmission of current through such a loop arrangement may generate magnetic fields and, depending on the frequency of the AC component of the current, may generate electromagnetic radiation.

[0007] The present disclosure provides a technique for eliminating or at least significantly reducing a magnetic field in a selected region. The technique utilizes determining or providing data regarding the arrangement of wires carrying current between one or more power sources and one or more loads or power consumers. Determining the arrangement of one or more current carrying coils / loops formed by the arrangement of wires that creates the current flowing in an effectively closed loop-like path. Providing one or more cancellation units formed by current carrying loops, an amplifier module, and a sensor module that cancel the magnetic field generated by the current passing through the effectively closed loop-like path. Providing current carrying coils / loops along paths corresponding to each effectively closed loop-like path of wires and utilizing the sensor module to provide data regarding the current carrying in each effectively closed loop-like path. Thus, the current flowing in the current carrying coils will be in the opposite direction to the current flowing in each effectively closed loop-like path, generating an opposing magnetic field that effectively cancels or at least significantly reduces the magnetic field generated by the electrical system.

[0008] Thus, according to a broad aspect, the present disclosure provides a method for use in reducing a magnetic field generated by an electrical system, the method comprising: determining one or more current-carrying loops in electrical wiring of an electrical system; providing a parallel wire loop for at least one of the one or more current-carrying loops that generally overlaps a physical path of the at least one current-carrying loop; connecting the parallel wire loops to a power system having at least one current sensor; activating the at least one current sensor to provide sensed data indicative of a current passing through the at least one current carrying loop; Equipped with Utilizing the sensing data, the power supply system is operated to deliver a current to the parallel wire loops, the current being opposite in direction to the current passing through the at least one current-carrying loop, thereby eliminating, or at least significantly reducing, a magnetic field generated by the current passing through the at least one current-carrying loop.

[0009] According to some embodiments, transmitting current in the parallel wire loops comprises providing a current equal (up to an acceptable measurement variation) to the current passing in the at least one current-carrying loop, and further, the phase / direction of the current transmitting through the parallel wire loops is 180 degrees (i.e., opposite direction) with respect to the current sensed in at least one or more current-carrying loops with an acceptable measurement variation.

[0010] According to some embodiments, utilizing the sensing data may comprise determining an AC component of a current passing through the at least one current-carrying loop and generating a current that is in anti-phase and similar amplitude to the AC component traveling in the parallel wire loops.

[0011] According to some embodiments, the electrical system may comprise an electric vehicle or an electric hybrid vehicle.

[0012] According to another broad aspect, the present disclosure provides a system for use in conjunction with an electrical system having one or more current carrying loops, the system comprising: A control unit; a conductive wire loop disposed parallel to and generally coinciding with the physical path of at least one of the one or more current-carrying loops; a current sensor arranged to determine sensed data of a current passing through the one or more current carrying loops and to communicate the sensed data to the controller; Equipped with The control unit is configured to transmit a counterbalancing current through the conductive wire loops, the counterbalancing current having an opposite direction to the current passing through at least one of the one or more current-carrying loops, thereby eliminating or at least significantly reducing a magnetic field generated by the current passing through the at least one current-carrying loop.

[0013] According to some embodiments, the controller may comprise a selected frequency filter arranged to filter the sensed data to provide filtered data indicative of selected frequency components of current flowing in at least one of the one or more current carrying loops, the controller being operated to convey a current corresponding to and in an opposite direction to the frequency components of the sensed data.

[0014] According to some embodiments, the control unit may comprise a high pass filter to filter the sensed data to provide filtered data indicative of an AC component, and the control unit is operated to deliver a current corresponding to and in the opposite direction to the AC component of the sensed data.

[0015] According to some embodiments, the frequency filter may be a bandpass filter arranged to transmit sensed data within one or more selected frequency ranges. This arrangement may also be used to provide a counter field for selected frequency ranges of a magnetic field.

[0016] According to some embodiments, the current sensor may be configured as a current clamp sensor having a phase shift less than a predetermined threshold. In some embodiments, the current sensor may be a field probe positioned to sense a magnetic field. The field probe may be positioned near one or more current carrying wires of the current carrying loop and provide sensed data indicative of current flow in the current carrying wires.

[0017] According to some embodiments, the one or more current carrying loops comprise a loop portion that passes through an electrical element of the electrical system.

[0018] According to some embodiments, the electrical system is an electric vehicle or a hybrid vehicle.

[0019] According to some embodiments, the portion of the one or more current carrying loops comprises one or more portions of a vehicle body.

[0020] According to some embodiments, the system may further comprise a differential current sensor providing differential sensing data to the controller indicative of a difference between a current conveying through each current carrying loop combined with a current conveying through the conductive wire loop, the controller being arranged to adjust the offset currents to reduce the differential sensing data.

[0021] According to yet another broad aspect, the present disclosure provides a system for use in conjunction with an electric or hybrid vehicle, the system comprising an electrical wiring arrangement having one or more current carrying loops, the system comprising: A control unit; a conductive loop disposed along at least one of the one or more current-carrying loops and generally coinciding with the physical path thereof; a current sensor positioned to determine sensed data of a current passing through at least one of the one or more current carrying loops and to communicate the sensed data to the controller; Equipped with The control unit is positioned to transmit a cancellation current through the conductive wire loops, the cancellation current having an opposite direction to the current passing through at least one of the one or more current-carrying loops, thereby eliminating or at least significantly reducing a magnetic field generated by the current passing through the at least one current-carrying loop.

[0022] According to some embodiments, the selection of one or more energized loops may be based on the proximity of the energized loop to the vehicle occupant space and / or the strength of magnetic or electromagnetic radiation generated by the energized loop and radiated into the vehicle occupant space.

[0023] For a better understanding of the subject matter disclosed herein, there is illustrated how it may be put into practice, and embodiments are described by way of non-limiting examples only with reference to the accompanying figures. [Brief description of the drawings]

[0024] [Figure 1A] 1A and 1B show an electrical system utilizing electrical elements and one or more current carrying loops, where FIG. 1A shows the system: [Figure 1B] FIG. 1B illustrates a configuration of a magnetic field cancellation system according to some embodiments of the present disclosure. [Diagram 2] FIG. 2 illustrates a configuration of a magnetic field cancellation system according to some embodiments of the present disclosure. [Diagram 3] FIG. 3 illustrates a configuration of a magnetic field cancellation system arranged to optimize output current, according to some embodiments of the present disclosure. [Figure 4] FIG. 4 is a flow chart diagram illustrating a magnetic field cancellation approach according to some embodiments of the present disclosure. [Diagram 5] FIG. 5 shows experimentally measured magnetic fields in a parked vehicle at shutdown and startup of a system according to the present disclosure. [Figure 6] FIG. 6 shows the experimentally measured magnetic field in a vehicle operating at low speed, at shutdown and startup of a system according to the present disclosure. [Figure 7] FIG. 7 shows experimentally measured magnetic fields in a vehicle driving in a city street, with a system according to the present disclosure at shutdown and startup. [Figure 8] FIG. 8 shows experimentally measured magnetic fields in a vehicle driving on an intercity road, with the system according to the present disclosure at shutdown and startup. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] As described below, the present disclosure provides systems and techniques for canceling magnetic fields generated within an electrical system. Referring to FIG 1A, a schematic of a system 100 generally uses electrical power to operate one or more loads 130A and 130B. Power is provided from a power source 120 (e.g., a battery pack / array) and transferred to the load 130 through lines 122, 124, 126, 128, and / or a ground contact G. FIG 1B illustrates the system 100 with the addition of a magnetic field cancellation system 200 according to some embodiments of the present disclosure.

[0026] As shown in FIG. 1A, power is transferred from source 120 to loads 130A and 130B using electrical current carrying transmission lines. For example, transmission line 122 may be comprised of a pair of twisted cables that transmit electrical current to source 120 and from source 120 to load 130A. In various circumstances, as a result of mechanical or electrical constraints, twisted cable 122 may split into first cable 126 and second cable 128 toward first and second or positive and negative contacts at load 130A. In this regard, depending on the electrical signaling scheme used by system 100, first cable 126 and second cable 128 may have various designations, such as positive / negative, phase / zero, etc. In general, regardless of the particular electrical signaling scheme, electrical current that travels through one of the cables to the load travels back through the other cable to source 120.

[0027] It should be noted that the power source 120 may be a DC or AC power source. For example, in a typical electric or hybrid vehicle, the power source 120 comprises one or more battery arrangements providing DC power. However, depending on the power consumption configuration and / or through the use of rectification circuitry, the output power may generally have an AC component.

[0028] The current path formed by the first cable 126 and the second cable 128 creates an effective current-carrying loop (CCL), with current being transferred in the loop CCL1 to the circuit of the load 130 A. The current flowing in the loop generates a magnetic field according to the magnitude and frequency variation of the current.

[0029] 1A shows another example, having a single power line 124 extending between the power source 120 and the load device 130B. In such a configuration, the load device 130B and the power source 120 are further connected to a common ground contact G, thereby completing an electrical circuit. The common ground may be, for example, the frame or chassis of the system 100. As a result, current is transferred through the power line 124 and the common ground contact G, creating a current-carrying loop CCL2.

[0030] It should be noted that in this connection, current carrying loop CCL1 and current carrying loop CCL2 are both shown simply to illustrate the major types of current loops found in electrical systems. It should also be noted that while power source 120 is shown here as a single power source, in a typical system, different CCLs may be connected to one or more different power sources to correspond with different loads and provide selected but not particularly similar output voltage and current characteristics. It should also be understood that CCLs may be configured anywhere along a conductive line and may relate to the distance between the separate electrical contacts at power source 120 and the electrical contacts at load 130, and / or other configurations where the electrical lines are spatially separated to create current loops.

[0031] The flow of current in the loop pattern reinforces the magnetic field generated by the moving charge. In general, direct current generates a static magnetic field, while an alternating current component generates fluctuations in the magnetic field and is associated with electromagnetic radiation having a frequency corresponding to the frequency of the alternating current. To eliminate or at least significantly reduce the magnetic field and / or electromagnetic radiation in a selected area near the electrical system 100, the present disclosure provides a system and method that utilizes one or more parallel wire loops. The one or more parallel wire loops are arranged to overlap one or more CCLs identified in the electrical system 100. More specifically, the one or more parallel wire loops may be arranged to align with the conductors of one or more CCLs to spatially coincide with the respective CCLs. The current transfer in the parallel wire loops is determined to be opposite in direction and preferably close in amplitude to the current flowing through the respective CCLs to effectively cancel the magnetic field generated by the current flowing through the CCLs. As shown in FIG. 1B, additional parallel wire loops 530a and 530b are arranged to generally overlap the current paths of CCL1 and CCL2. In other words, the parallel wire loops 530a and 530b are positioned to spatially coincide with the physical path of each CCL, so that the CCL and each parallel wire loop 530 act as a common source of a magnetic field.

[0032] As shown in FIG. 1B, the parallel wire loops 530a and 530b are arranged to overlap the current paths that define the current carrying loops CCL1 and CCL2. The parallel wire loops 530a and 530b are connected to an electrical control system 200 having at least an amplifier 510 and a sensor 520. The system 200 may include a controller 500 that enables appropriate system operation and control. For simplicity of illustration, the system 200 is illustrated as being connected to only the parallel wire loop 530a. However, it should be understood that the parallel wire loop 530b is also connected to a corresponding system 200, either the same or a separate control system. Furthermore, it should be understood that each parallel wire loop 530 and each control system 200 is associated with one or more sensors 520 and arranged to sense the current in a selected transmission line that supplies a corresponding CCL.

[0033] The current sensor 520 is positioned to provide sensed data indicative of the current transmitted in one or more current carrying lines feeding the respective current carrying loops. In general, the current sensor 520 may be any type of current sensing device capable of generating real-time data about the current passing through the respective current carrying line / wires, such as a clamp sensor. In some configurations, the current sensor 520 may be replaced by a field probe positioned to determine the magnetic field at a selected location near the current carrying line. Preferably, to enable cancellation of high frequency electromagnetic fields, the sensor 520 is a current sensor configured to generate sensed data indicative of the current and the fluctuations in the current. The sensor may be a wideband sensor having a known frequency response function, such as a flat phase response function. Alternatively, the controller 500 may be connected to compensate for fluctuations in the frequency response function of the sensor 520, for example when the response function is unknown. This may be used to provide accurate phase of the sensed data indicative of the fluctuations in the alternating current and enable cancellation of the electromagnetic fields generated by the fluctuating current. In some configurations, the current sensor 520 may have a phase difference at one or more selected frequency ranges below a predetermined threshold. This configuration allows for the selection of a current sensor based on the frequency range in which the electrical system 100 operates, where the range of frequencies of the electromagnetic fields generated by each CCL are cancelled out. The current sensor 520 may be a transducer suitable for measuring alternating currents such as fast transient currents, pulsed currents in a power supply, or sinusoidal currents in a power line in one or more selected frequency ranges. For example, the current sensor 520 may be a Rogowski coil current probe or other suitable current probe.

[0034] The sensor 520 is configured to provide current sensing data to the amplifier unit 510. The amplifier 510 is configured to receive the current sensing data and transmit a corresponding current to the connected parallel wire loops 530. The electrical connections between the amplifier 510, the parallel wire loops 530, and the sensor 520 are configured to provide an output current from the amplifier 510 in a direction opposite to the sensed current flowing in the respective CCL. Furthermore, the amplitude of the current transmitting through the parallel wire loops 530 is largely similar to the amplitude of the sensed current in the respective CCL. More specifically, considering that the sensor 520 provides sensed data indicative of a current I(t), the amplifier 510 is controlled to provide an output cancellation current -kI(t), where k is less than or equal to 1. With this configuration, the parallel wire loops 530 are controlled to generate electromagnetic fields of equal magnitude and opposite direction to the electromagnetic fields generated by the respective CCLs, effectively canceling the electromagnetic fields generated by the CCLs. Thus, the amplifier 510 may provide an output signal with a phase relationship selected according to its frequency response function and known by inputting the sensed data of the detected current. The phase relationship is preferably flat and may be similar or opposite to the output signal. As shown above, the frequency domain of the frequency response function may be selected according to the frequency domain of the current fluctuations in the system 100, thereby allowing for effective cancellation of the electromagnetic fields generated by each CCL. In general, the amplifier 510 may be a two-stage amplifier or more, with a variable gain amplifier stage and a power amplifier stage. Control of the variable gain amplifier allows adjustment of the amplifier parameter k to provide k~l, for example to reduce the function |k-1|.

[0035] An exemplary configuration of a magnetic field cancellation system 200 in some embodiments of the present disclosure is shown in FIG. 2. As shown, the system includes a current sensor 520 and an amplifier 510 arranged to sense the current in one or more wires 122 / 124 feeding a selected current loop. The system 200 may also include a controller 500 that provides processing and a user interface for operating the system. The amplifier 510 may be a two-stage amplifier, including a first variable gain amplifier 512 with a known phase difference in a selected frequency range, and a power amplifier stage 516. In some configurations, the amplifier unit 510 may also include a phase compensation circuit 514 and be configured to align the amplified signal to the phase of the current measured by the sensor 520 according to the known phase difference of the variable gain amplifier 512. The power amplifier stage 516 provides an output current, generally similar in magnitude and opposite in phase to the current measured by the sensor 520. The output current is directed to flow through parallel wire loops 530, which are positioned to sufficiently overlap selected CCLs in the system, as described herein, thereby canceling the magnetic fields generated by the CCLs.

[0036] For example, the amplifier device 510 may be selected according to one or more requirements. The first requirement is based on phase difference. Thus, the amplifier should be capable of operating with a predetermined, and preferably zero, phase difference. The amplifier 510 may be selected to have one or more electrical requirements, as shown in Table 1.

[0037] [Table 1]

[0038] In general, the amplifier may operate over a range of amplification that allows for input voltages of 1-50 mVrms, output currents of 0.1-5 Arms, total harmonic distortion of less than 5%, and phase differences of less than 1 degree over a selected frequency range. Amplifier 510 may have under-voltage protection and may be configured with two supply lines with internal summing.

[0039] However, the presence of static magnetic fields is generally undesirable, and the cancellation of such static magnetic fields is generally of less concern than fluctuating magnetic or electromagnetic fields, generally due to the potential adverse health effects known to be associated with fluctuating electromagnetic fields. To this end, the assessment of the CCL may be determined according to the amplitude and frequency of the fluctuations in the current. Furthermore, the sensing data and amplifier may be configured to provide parallel wire loops, with a current pattern that eliminates the AC component of the current in the CCL, eliminating or at least significantly reducing the electromagnetic field generated by the CCL. In some configurations, the sensor 520 is configured to provide sensing data indicative of the AC component of the current in a frequency range of 10 Hz to 5 kHz. In this manner, the amplifier 510 may be configured to operate in a selected frequency range and take into account possible phase differences in the selected frequency range.

[0040] The control to cancel the magnetic field generated by the AC component of the current allows for energy savings since it eliminates the need to transmit high DC currents to counter the DC component of the current loop. For this purpose, the amplifier 510 may transmit AC components in a selected frequency range (e.g., above a selected threshold) in conjunction with a high-pass filter applied to remove the DC component from the sensed data. This configuration is used to reduce the components of the electromagnetic field that exceed the slowly varying magnetic field, thereby operating with reduced energy and reduced current transmission in the parallel wire loop. Furthermore, as will be explained in more detail below, the power required to cancel the magnetic field using this technique is related to the current used, which is multiplied by the load of the parallel wire loop 530. Appropriate selection of the parameters of the loop 530, such as resistance and inductance, can reduce the control power of the system.

[0041] Furthermore, in some embodiments, the amplifier 510 may be associated with a bandpass filter adapted to filter selected frequency ranges from the sensed signal, allowing transmission of alternating current components in selected frequency bands to cancel selected frequency bands of magnetic fields. In some additional configurations, the amplifier 510 may be associated with a lowpass filter, which may be used to cancel stronger low frequency magnetic fields than others.

[0042] As indicated above, the current cancellation system 200 according to the present disclosure may also include a controller 500. The controller 500 may generally include a processor, memory, and user interface module and may be configured to provide control functions to the system 200. As such, the controller 500 may include a processor and memory circuitry (PMC) and be operatively connected to hardware based I / O interfaces that control the operation of the sensor 520 and the amplifier 510. The controller 500 may be configured to provide the processing necessary to operate the system 200 and may include, in more detail herein, a processor (not shown separately) and a memory (not shown separately). The processor of the controller 500 may be configured to execute a number of functional modules in accordance with computer readable instructions embodied in a non-transitory computer readable memory included within the controller 500. Such functional modules are described hereinafter as being included within the controller 500.

[0043] In some embodiments, sensed data collected by the current sensor 520 may be transmitted to the controller 500 for processing and determining the pattern of the current transmitted by the amplifier 510 through the parallel wire loop 530. Such processing may be used in configurations where the current delivered to the load follows a selected pattern, and thus parameters of the current may be predicted. In other configurations where the pattern of the current may vary without a clearly predictable pattern, an analog style of control may be preferred. In analog style control, the sensed current signal is amplified and transmitted in antiphase through the parallel wire loop 530.

[0044] The electrical system 100 may be any system that generally uses electrical power for operation. In some embodiments of the present disclosure, the system 100 may be a vehicle, such as an electric or hybrid vehicle. In such vehicles, occupants may spend extended periods of time inside the vehicle and may generally be exposed to high magnetic and electromagnetic fields generated by the vehicle's electrical system. The present approach uses currents in one or more parallel wire loops placed at selected locations to cancel or at least significantly reduce the electromagnetic fields exerted on occupants inside the vehicle.

[0045] A further example is shown in FIG. 3, which depicts a system 200 for magnetic field cancellation. The system 200 is illustrated having a parallel wire loop 530 and is arranged to overlap a CCL (marked with a dashed line) extending between the power source 120 and the load 130. The system 200 utilizes a current sensor 520 arranged to provide data of the current feeding the CCL (the sensor may be arranged along the CCL or along the wire feeding the CCL as illustrated above). The current sensor provides the current data to an integrator 511, which is configured to control a variable gain amplifier 512 (or provides the current data directly to the amplifier 512). When the output current is delivered by the power amplifier stage 516, the controller may operate to adjust the gain for optimized magnetic field cancellation. To this end, an additional current sensor 522 may be arranged to measure the total current delivered through the CCL and the parallel wire loop 530 and provide the current data to the controller 500. Thus, controller 500 is configured to adjust the gain and phase levels to reduce the current sensed by sensor 522 and coupled into the currents in CCL and loop 530. Sensor 522 is thus configured to provide differential sensing data indicative of the difference in currents conducted through CCL and each loop 530. This configuration provides a simple feedback system for accurate magnetic field cancellation by providing opposing currents in overlapping loops.

[0046] In this regard, the present disclosure provides a method for use in reducing magnetic and electromagnetic fields generated by an electrical system in a selected area. Please refer to FIG. 4, which shows a flow chart illustrating the operation of the method of the present disclosure. As shown, the method includes determining one or more current carrying loops in the conductive lines of the system. This may include examining 4010 the conductive lines in the system and determining 4020 one or more CCLs. As a typical electrical system may have many electrical components (loads) and thus many CCLs, the method may include determining 4030 an EMF score for the CCLs. This may include determining a selected set of parameters related to the current and magnetic field generated by each CCL. For example, the score may include parameters such as the magnitude of the current, the amplitude and frequency of typical current fluctuations (AC component) transmitted to each CCL, the magnetic field and electromagnetic field pattern generated by the CCL, and the spatial area affected by the field radiation by the CCL. As is known, the magnitude of the DC component determines the magnitude of the static magnetic field generated by the CCL. The amplitude and frequency of the current fluctuations (AC component) determine the frequency and magnitude of the electromagnetic field generated by the CCL. Preferably, a larger amplitude of the AC component may receive a higher score. The scoring may be used to determine which CCLs generate stronger magnetic fields and thus should be treated with parallel wire loops in accordance with the present disclosure. However, depending on the predetermined number of CCLs to treat, the number of parallel wire loops is selected 4040 according to the number of CCLs in the system selected for cancellation.

[0047] As described above, for each selected CCL, the technique includes providing 4050 a respective parallel wire loop. The parallel wire loops are aligned 4060 to spatially overlap / coincide with the respective CCL. In this regard, the CCL may be configured directly on the conductive line, such as CCL1 in FIG. 1A. However, some CCLs may include a chassis portion, such as CCL2 in FIG. 1A. In this case, the parallel wire loops may be generally aligned to overlap an approximation of the shortest path of current transfer through the chassis.

[0048] For each parallel wire loop, the technique involves using a corresponding sensor 4070 to determine sensed data of the current passing through each CCL. The sensors may be placed at any convenient location along the conductive lines feeding each CCL. The sensed data is collected and used to generate currents of opposite phase and preferably similar amplitude, which are propagated 4080 through the parallel wire loops. The opposing currents propagating through the parallel wire loops generate electromagnetic fields that are in the opposite direction to the electromagnetic field generated by each CCL, thus reducing and preferably canceling the overall electromagnetic field.

[0049] It should be noted that the currents transmitted through the parallel wire loops are as close as possible, and preferably equal, in magnitude to those transmitted through each CCL. However, the power transmitted through the parallel wire loops may be very small, since this current is not used to operate one or more load devices as the current transmitted through the CCL. More specifically, the system 200 described herein may be optimized for a selected power consumption, which is a measurable parameter for magnetic field cancellation and is related to the current flowing through each loop 530, while the voltage supplied to transmit such current may be selected according to the resistance of the loop 530 so as not to exceed a selected power threshold. More specifically, the approach is such that, due to the transmission of current through the parallel wire loops 530, the parallel wire loops 530 do not need to create a force, but rather a magnetic field. Thus, the power consumption of the system is approximately balanced by the current generated times the load through the parallel wire loops 530. The load of loop 530 may be chosen to be very small (eg, just the resistance and inductance of the coil), thereby reducing power consumption.

[0050] In general, the effective cancellation of the electromagnetic fields generated by the CCLs in the electrical system 100 is determined not only by the spatial overlap between the CCLs and each parallel wire loop, but also by the relationship between the currents passing through the CCLs and the respective cancellation currents. Thus, the present approach may depend on the spatial overlap between the parallel wire loops and each CCL. Generally, using standard approaches and considering the complexity of the CCL paths, a 10-25% variation in the overlap can be tolerated to reduce the generation of the electromagnetic fields. Generally, the parallel wire loops are configured to spatially coincide with the physical paths of the CCLs, tolerating acceptable variations due to physical limitations. Furthermore, while precise overlap between the parallel wire loops and each CCL provides optimized cancellation of the magnetic fields, any variation in the overlap can result in reduced cancellation of the magnetic fields. The acceptable overlap is generally sufficient to reduce the magnetic fields to World Health Organization acceptable levels. Additionally, in typical electrical systems such as electric or hybrid vehicles, load devices that draw high current are typically connected using a pair of conductive wires, resulting in a configuration associated with CCL2 rather than CCL1 in FIG. 1B, with the current being transmitted in part through the chassis of system 100. This arrangement allows for improved overlap and increased electromagnetic field cancellation efficiency.

[0051] The method was tested using a commercially available electric vehicle, the Hyundai Ioniq. The vehicle has two main electrical systems: a low voltage (e.g., 12V) electrical wiring with earth connection through the vehicle chassis, and a high voltage electrical wiring that connects the battery and is isolated between the positive and negative plugs to generate the CCL. The magnetic field inside the vehicle passenger compartment was measured using a magnetic field measuring device (e.g., Tenmars TM-192\D 3-axis magnetometer) while the vehicle was driving and stationary, when the aforementioned magnetic field cancellation system was turned off and on. Figures 5 to 8 show the magnetic field measurements during different vehicle operating conditions. Figure 5 shows a comparison of the magnetic field measurements when the vehicle was stationary, Figure 6 shows a comparison of the magnetic field measured during low speed driving of the vehicle, Figure 7 shows a comparison of the magnetic field measured during urban driving in the city, and Figure 8 shows the magnetic field measured during interurban driving. To provide magnetic field cancellation, two parallel wire loops were placed in the vehicle. The first loop was placed to overlap the CCL formed by the split of the twisted pair of wires transmitting electricity from the high voltage battery to the voltage converter in the vehicle. The first loop corresponds generally to the parallel wire loop 530a shown in FIG. 1B. The second loop extends to overlap the CCL connecting the low voltage battery device and the voltage converter of the vehicle. The second loop corresponds generally to the parallel wire loop 530b shown in FIG. 1B. As described above, the second loop has a path for the current to transmit through the chassis portion of the vehicle.

[0052] In more detail, Figure 5 shows the magnetic field measured at the rear seat of a car when the car is started and in park gear. As shown, when the magnetic field cancellation system MFC described above is off (MFC OFF), the magnetic field at the passenger seat is measured at 20-25 mG. The magnetic field measured with the system on (MFC ON) is seen to be in the range of 2.5-7 mG, and most often in the range of 2.5-3 mG. Figure 6 shows similar results measured during low speed driving when the car is driven using the electric motor. The measured magnetic field was reduced from 20-25 mG to about 4 mG by operation of the present technique.

[0053] In Figures 7 and 8, the magnetic field was measured during driving in real lie environments. Figure 7 shows measurements taken during city driving, where the magnetic field was reduced from a range of 20-25mG, with a peak of 25-30mG, to about 4mG, with a peak of 7-8mG. Figure 8 shows the magnetic field measured during interurban and highway driving. As shown, while driving at a relatively high speed, the magnetic field was measured at 15-23mG, with a peak of about 27mG, with the system off. When the system was turned on, it provided a reduction in the magnetic field to about 5-7mG. This situation may be different in electric vehicles that rely only on electric motors, keeping in mind that some electric motors operate with currents of varying frequency, so an increased frequency will rotate the motor at a faster speed, resulting in a higher vehicle speed.

[0054] In general, magnetic field measurements by devices provide measurements of the magnetic field over time. Results show that the magnitude of the magnetic field vector is related, which is determined based on the field magnitude measured in three orthogonal axes over time. Magnetic field instruments operate on an impulse response and provide bandpass filters ranging from a few Hz to a few kHz. The measured magnetic field is therefore related to an alternating component (e.g. frequencies above 0 Hz).

[0055] The present disclosure therefore provides a system and method suitable for eliminating or at least significantly reducing magnetic fields generated by currents in the system, the method being particularly applicable to operation in electric or hybrid vehicles, reducing magnetic and electromagnetic fields in the area of ​​the vehicle's passenger seats. As indicated above, the method is based on the inventors' understanding of the arrangement of current-carrying loops in an electrical system, and the role of such current-carrying loops in generating magnetic fields in the vicinity of the system.

Claims

1. 1. A method for use in reducing a magnetic field generated by an electrical system, comprising: determining one or more current-carrying loops in electrical wiring of the electrical system; providing at least one of the one or more current-carrying loops with a parallel wire loop that generally overlaps a physical path of the at least one current-carrying loop; connecting the parallel wire loops to a power system having at least one current sensor; operating the at least one current sensor to provide sensed data indicative of a current passing through the at least one current carrying loop; utilizing the sensed data to operate the power supply system to transmit a current through the parallel wire loops, the current flowing in an opposite direction to a current flowing through the at least one current carrying loop; thereby eliminating or at least significantly reducing a magnetic field generated by a current passing through the at least one current carrying loop; method.

2. the current traveling through the parallel wire loops is equal to the current passing through the at least one current carrying loop; The method of claim 1.

3. The use of the detection data includes: determining an AC component of a current passing through the at least one current-carrying loop; generating and transmitting currents in opposite phase and similar amplitude to the AC component through the parallel wire loops; The method according to claim 1 or 2.

4. The electrical system includes an electric vehicle or a hybrid vehicle.

4. The method according to any one of claims 1 to 3.

5. 1. A system for cooperating with an electrical system having one or more current carrying loops, comprising: A control unit; a conductive wire loop disposed along at least one of the one or more current-carrying loops and generally coinciding with a physical path thereof; a current sensor arranged to determine sensed data of a current passing through the at least one of the one or more current carrying loops and to communicate the sensed data to the controller; Equipped with the control unit is configured to transmit a counterbalancing current through the conductive line loop, the counterbalancing current having an opposite direction to a current passing through the at least one of the one or more current carrying loops, thereby eliminating or at least significantly reducing a magnetic field generated by the current passing through the at least one. system.

6. The control unit is a frequency filter configured to process the sensed data to provide filtered data indicative of selected frequency components of current flowing through the at least one of the one or more current carrying loops; the control unit is operated to transmit a current that corresponds to and is opposite to the frequency components of the sensed data. The system of claim 5.

7. the frequency filter being a high pass filter configured to filter the sensed data and provide AC component filtered data. The system of claim 6.

8. the frequency filter being a bandpass filter configured to allow transmission of a selected frequency range; The system of claim 6.

9. The current sensor is configured as a current clamp sensor having a phase difference less than a predetermined threshold. A system according to any one of claims 5 to 8.

10. the current sensor being configured as a field probe positioned to sense a magnetic field in the vicinity of one or more wires of the current carrying loop; A system according to any one of claims 5 to 8.

11. the at least one current carrying loop includes a loop portion passing through an electrical element of the electrical system. A system according to any one of claims 5 to 10.

12. The system is an electric vehicle or a hybrid vehicle. A system according to any one of claims 5 to 11.

13. the portion of the at least one current carrying loop comprises one or more portions of a vehicle body; The system of claim 12.

14. Further comprising a differential current sensor; providing the control unit with difference detection data indicating a difference between the current of the conductive wire loop and the collective current of each current-carrying loop; The control unit is configured to adjust the offset current to reduce the difference detection data. A system according to any one of claims 5 to 13.

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