Fluxgate current sensor
The fluxgate current sensor system addresses the challenge of measuring DC and AC currents by using a classification model to differentiate and adjust calculation windows, enhancing accuracy and interference resistance in electric vehicles and energy storage systems.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- HONEYWELL INTERNATIONAL INC
- Filing Date
- 2025-10-16
- Publication Date
- 2026-05-19
AI Technical Summary
Existing current sensors face challenges in accurately measuring both direct current (DC) and alternating current (AC) in complex applications such as electric vehicles and energy storage systems, requiring robust sensing that can distinguish and measure both types of currents effectively.
A fluxgate current sensor system that includes a magnetic core, coil, oscillator circuit, sampling resistor, amplifier, and controller, which uses a classification model to determine operating conditions and select appropriate calculation windows based on signal characteristics to accurately measure DC or AC currents, employing a rule-based model to differentiate between DC and AC signals and adjust calculation windows accordingly.
The system provides precise measurement of both DC and AC currents by improving interference immunity and accuracy, ensuring reliable current sensing in diverse applications.
Smart Images
Figure 2026082704000001_ABST
Abstract
Description
[Technical Field]
[0001] This disclosure relates to current sensors, and more particularly to fluxgate current sensor measurements. Several exemplary embodiments relate to fluxgate current sensors under alternating current operation. [Background technology]
[0002] The applicant recognizes the numerous technical challenges and difficulties associated with current sensor measurement. Through efforts, ingenuity, and innovation, the applicant has addressed many of these identified problems by developing the embodiments of the present disclosure, which are described in detail below. [Overview of the project]
[0003] The various embodiments described herein relate to current sensors, and more particularly to fluxgate current sensor measurements. Some exemplary embodiments relate to fluxgate current sensors under alternating current (AC) operation.
[0004] According to one aspect of the present disclosure, a method for measuring current using a fluxgate sensor is provided. In some embodiments, the method includes: receiving a fluxgate signal corresponding to a primary current, wherein the fluxgate signal comprises at least two plateau periods, each plateau period defining a plurality of candidate calculation windows; generating an operating condition classification based on the signal characteristic set by applying the signal characteristic set to a classification model, wherein the operating condition classification is one of (i) an AC operating condition indicating an AC primary current, or (ii) a DC operating condition indicating a DC primary current; selecting a calculation window from a plurality of calculation windows based on the operating condition classification, wherein the plurality of calculation windows comprises a first calculation window and a second calculation window; and generating a predicted current value for the primary current by applying sampled current values in the selected calculation window to a prediction model for each of at least two plateau periods, wherein generating the predicted current value includes generating an average of the sampled current values.
[0005] In some embodiments, the fluxgate signal is received from the fluxgate excitation and sampling module.
[0006] In some embodiments, the method further includes generating a set of signal characteristics based on a flux-gated signal by performing an analysis on the flux-gated signal.
[0007] In some embodiments, the signal characteristics set includes (i) peak signal data, (ii) signal dispersion data, and (iii) cycle data.
[0008] In some embodiments, generating an operating condition classification includes determining whether (i) the peak signal data meets the peak threshold, (ii) the variance data meets the variance threshold, and (iii) the cycle data meets the cycle threshold.
[0009] In some embodiments, generating an operating condition classification further includes generating the operating condition classification as a DC operating condition classification in response to determining that (i) the peak signal data does not meet the peak threshold and (ii) the variance data does not meet the variance threshold.
[0010] In some embodiments, generating an operating condition classification further includes generating the operating condition classification as an AC operating condition classification in response to determining that (i) peak signal data satisfies a peak threshold, or (ii) variance data satisfies a variance threshold.
[0011] In some embodiments, the classification model is a rule-based model that includes multiple rules, and generating an operating condition classification involves comparing a set of signal characteristics with one or more thresholds.
[0012] In some embodiments, selecting a calculation window from a plurality of calculation windows based on an operating condition classification includes selecting a first calculation window in response to a DC operating condition classification, wherein the first calculation window has a length shorter than the length of each of at least two plateau periods.
[0013] In some embodiments, selecting a calculation window from a plurality of calculation windows based on an operating condition classification includes selecting a second calculation window in response to an AC operating condition classification. [Brief explanation of the drawing]
[0014] The description of the illustrated embodiments can be read in conjunction with the accompanying figures. Unless otherwise noted, it should be understood that for the sake of simplification and clarity, the elements shown in the figures are not necessarily drawn to scale. For example, unless otherwise noted, the dimensions of some elements may be exaggerated relative to others. Embodiments incorporating the teachings of this disclosure are shown and described in relation to the figures presented herein. [Figure 1]A block diagram of an exemplary fluxgate current sensor according to at least one embodiment of the present disclosure is provided. [Figure 2] The present disclosure provides an exemplary flux-gated signal waveform of a primary current according to at least one exemplary embodiment. [Figure 3] An exemplary flux-gated signal waveform comparison plot is provided according to at least one exemplary embodiment of the present disclosure. [Figure 4] A flowchart illustrating the operation of an exemplary method for measuring current using a fluxgate current sensor, according to at least one embodiment of the present disclosure, is provided. [Figure 5] The present disclosure provides exemplary flux-gate signals having different frequencies according to at least one exemplary embodiment. [Modes for carrying out the invention]
[0015] Next, some embodiments of this disclosure will be described in more detail below with reference to the accompanying drawings, which show some, but not all, embodiments of this disclosure. In fact, these disclosures may be embodied in many different forms and should not be construed as being limited to the embodiments described herein, but rather these embodiments are provided so that this disclosure may satisfy applicable legal requirements. Similar figures refer to similar elements throughout.
[0016] Terms such as “calculate,” “determine,” “generate,” and / or similar words are used interchangeably in this specification to refer to the creation, modification, or identification of data. Furthermore, “based on,” “partially based on,” “at least based on,” “based on,” and / or similar words are used interchangeably in this specification in an open-ended manner to indicate that the data is based only on the referenced element, or not to indicate that it is based only on the referenced element unless otherwise indicated. Similar numbers refer to similar elements throughout.
[0017] As used herein, terms such as "front", "rear", "top", etc. are used for illustrative purposes to describe the relative position of a particular component or a part of a component in the embodiments provided below. Further, as will be apparent to those skilled in the art from the perspective of the present disclosure, the terms "substantially" and "approximately" indicate that the referenced element or related description is within the accuracy of applicable engineering tolerances.
[0018] As used herein, the term "comprising" means including but not limited to and should be construed as typically used in the patent context. The use of broader terms such as "comprises", "includes", and "having" should be understood to support narrower terms such as "consisting of", "consisting essentially of", and "comprised substantially of".
[0019] Phrases such as "in one embodiment", "according to one embodiment", and similar phrases generally mean that the particular feature, structure, or characteristic following such phrases may be included in at least one embodiment of the present disclosure and may be included in more than one embodiment of the present disclosure (importantly, such phrases do not necessarily refer to the same embodiment).
[0020] As used herein, the word "example" or "exemplary" means "serving as an example, instance, or illustration". Any embodiment described herein as "exemplary" should not necessarily be construed as more preferred or advantageous than other embodiments.
[0021] When this specification states that a component or feature "may include / have", "can include / have", "may include / have", "should include / have", "will include / have", "preferably includes / has", "optionally includes / has", "typically includes / has", "optionally includes / has", "for example includes / has", "in many cases, includes / has" or "may include / have" (or other such words), a particular component or feature need not be included or have the feature. Such a component or feature may optionally be included in some embodiments or may be excluded.
[0022] As used herein, the term "or" is used in both an alternative and a conjunctive sense unless otherwise indicated. The terms "illustrative" and "exemplary" are used as examples without indication of a quality level. Terms such as "calculate", "determine", "generate", and / or similar words are used interchangeably herein to refer to the creation, modification, or identification of data. Further, "based on", "partially based on", "at least based on", "based upon", and / or similar words are used interchangeably herein in an open-ended manner such that, unless otherwise indicated as being based only on the referenced element or elements, it is not shown to be so based. Like numerals refer to like elements throughout.
[0023] Fluxgate is a current sensing technology that can be used in a variety of current measurement applications, including current measurement in electric vehicles (EVs) and energy storage systems (ESS). Fluxgate current sensors can be used to measure direct current (DC) and / or alternating current (AC). For example, many applications may include DC primary current and AC primary current that need to be measured. For example, many electric vehicles include DC primary current such as DC charging and discharging, as well as AC primary current such as PTC, charging AC harmonics, and / or others. Such complex application scenarios may require, for example, a battery pack current sensor (e.g., in an electric vehicle or other device / system) to accurately detect not only the DC current but also the AC primary current. Therefore, there is a need for robust current sensing that can accurately measure both DC primary current and AC primary current.
[0024] Figure 1 is a block diagram of an exemplary fluxgate current sensor 100 according to at least one embodiment of the present disclosure. As shown in Figure 1, the fluxgate current sensor 100 comprises a magnetic core 104, a coil 106, a fluxgate oscillator circuit 108, a sampling resistor 110, an amplifier 112, an analog-to-digital converter (ADC) 114, and a controller 116. In some embodiments, the fluxgate oscillator circuit 108, the sampling resistor 110, the amplifier 112, and / or the ADC 114 may collectively define the fluxgate excitation and sampling module of the fluxgate current sensor 100. For example, the fluxgate excitation and sampling module of the fluxgate current sensor 100 may include the fluxgate oscillator circuit 108, the sampling resistor 110, the amplifier 112, and / or the ADC 114.
[0025] The magnetic core 104 may be circular, for example, a circular toroid as illustrated. The coil 106 is wound around the magnetic core 104 and includes two ends 122 connected to the fluxgate oscillator circuit 108. The fluxgate oscillator circuit 108 is also connected to a sampling resistor 110. In this regard, the coil 106 is connected to the sampling resistor 110. In some embodiments, as shown in Figure 1, the coil 106 is connected in series with the sampling resistor. The sampling resistor 110 may be, for example, a low-resistance resistor connected in series with the fluxgate oscillator circuit 108. The fluxgate oscillator circuit 108 circulates the coil 106 (for example, in forward and reverse directions) to generate an excitation signal on the coil 106, thereby generating an excitation current, such as a periodic signal, within the coil 106.
[0026] In some embodiments, the fluxgate oscillator circuit 108 includes an H-bridge circuit configured to generate a periodic excitation signal. The characteristics of the excitation signal, such as the oscillation period and platform amplitude, may be influenced by the voltage from the power supply 118 (e.g., the drive voltage), the magnitude of the primary current 124, and / or the inductance of the coil 106.
[0027] In various embodiments, an excitation signal on coil 106 (e.g., corresponding to an excitation current on coil 106) is sampled, and the sampled excitation signal is processed (e.g., signal processing) to measure the current value of the primary current 124. In various embodiments, sampling and processing the excitation signal includes sampling and processing a voltage signal 120 of a sampling resistor 110. For example, the voltage signal 120 of the sampling resistor 110 may correspond to an excitation signal. As described above, in some embodiments, the sampling resistor 110 is connected in series with the sampling resistor 110, and therefore the current flowing through the sampling resistor 110 is the same as the current flowing through coil 106. In this regard, in some embodiments, the fluxgate current sensor 100 detects the voltage signal 120 of the sampling resistor 110 (e.g., based on the characteristics of the easily saturating inductance) and processes the voltage signal 120 to determine the current value of the primary current 124. The sampled signal may be referred to herein as the fluxgate signal.
[0028] In various embodiments, the amplifier 112 is configured to amplify the voltage signal 120 of the sampling resistor 110. For example, processing the excitation signal may include the amplifier 112 receiving the voltage signal 120 and outputting the amplified voltage signal 120 (referred to herein interchangeably as the fluxgate signal) to the controller 116. As shown in Figure 1, the amplifier 112 may output the amplified voltage signal 120 to the controller 116 through the ADC 114. In some embodiments, the controller 116 is configured to calculate the current value of the primary current 124 (e.g., the current to be measured). In some embodiments, the controller 116 is a microcontroller.
[0029] In some embodiments, the controller 116 includes a processor, memory, input / output circuits, and / or communication circuits to perform and carry out another operation described herein with respect to the fluxgate current sensor 100. For example, the controller 116 may include a set of circuits, which may include a processor, memory, input / output circuits, and / or communication circuits. For example, the controller 116 may include a processor configured to process the signal output by the ADC 114, including calculating the current value of the primary current 124. In some embodiments, the memory is configured to store software and / or firmware, which, together with the processor and other circuits, is configured to process the signal output by the ADC 114, including calculating the current value of the primary current 124, by providing instructions such as computer instructions or computer code. In some embodiments, the controller 116 may communicate with other devices using communication circuits. For example, the communication circuit includes one or more communication components that enable communication between the fluxgate current sensor 100 (e.g., its controller 116) and other devices. As a non-limiting example, one or more communication components may include a controller area network (CAN) bus that enables communication between the fluxgate current sensor 100 (e.g., its controller 116) and other devices. The controller 116 may include a CAN bus (e.g., including CAN Low and / or CAN High) that enables communication with other devices.
[0030] In some embodiments, the term "circuit" includes hardware, and in some embodiments, it includes software for configuring the hardware. For example, in some embodiments, a circuit includes processing circuits, storage media, network interfaces, input / output devices, etc. Alternatively or additionally, in some embodiments, other elements of the controller 116 provide or complement the functionality of another particular set of circuits. For example, in some embodiments, a processor provides processing functionality to one of the set of circuits, memory provides storage functionality to one of the set of circuits, communication circuits provide network interface functionality to one of the set of circuits, and so on.
[0031] In some embodiments, the controller 116 may be embodied as one or more complex programmable logic devices (CPLDs), microprocessors, multicore processors, coprocessing entities, application-specific instruction-set processors (ASIPs), and / or microcontrollers. In some embodiments, the controller 116 may be embodied as integrated circuits, application-specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), programmable logic arrays (PLAs), hardware accelerators, digital circuits, and the like.
[0032] In some embodiments, the fluxgate current sensor 100 and / or a portion thereof may be embodied by one or more systems and / or devices.
[0033] Figure 2 provides an exemplary fluxgate signal waveform 200 of a current to be measured according to at least one exemplary embodiment of the present disclosure. Specifically, Figure 2 provides an exemplary acquisition period of a fluxgate signal (e.g., reflecting an excitation current on coil 106) generated by a fluxgate oscillator circuit 108. The fluxgate signal waveform 200 (e.g., the acquisition period of the fluxgate signal) may include a saturation-unsaturation region (e.g., at least one saturation and unsaturation region) and a plateau period. As shown in Figure 2, in some embodiments, the fluxgate signal waveform 200 includes at least three saturation-unsaturation regions 204A-C (e.g., unstable regions) and at least two plateau periods 210A, 210B. For example, the acquisition period of the fluxgate signal represented by the fluxgate signal waveform may include a first saturation-unsaturation region 204A, a second saturation-unsaturation region 204B, and a third saturation-unsaturation region 204C. Additionally, the fluxgate signal waveform 200 (for example, the acquisition period of the fluxgate signal represented therein) may include a first plateau period 210A and a second plateau period 210B. In some examples, the amplitudes of the first plateau period 210A and / or the second plateau period 210B may vary.
[0034] In some embodiments, the plateau period (e.g., plateau periods 210A, 210B) is the region between two consecutive saturated-unsaturated regions (e.g., between 204A and 204B, and between 204B and 204C). The plateau period may have a predetermined length. In some embodiments, the length of the plateau period may reflect a region within the acquisition period of a substantially stable flux-gate signal.
[0035] Figure 3 provides an exemplary fluxgate signal waveform comparison plot 300 according to at least one exemplary embodiment of the present disclosure. Specifically, Figure 3 shows an exemplary fluxgate signal waveform 300A of the DC current type and an exemplary fluxgate signal waveform 300B of the AC current type. Such a fluxgate signal waveform 300A may be referred to herein as the DC fluxgate signal waveform 300A. The fluxgate signal waveform 300A represents the acquisition period of a first fluxgate signal corresponding to a DC current, and the fluxgate signal waveform 300B represents the acquisition period of a second fluxgate signal corresponding to an AC current. Such a fluxgate signal waveform 300B may be referred to herein as the AC fluxgate signal waveform 300B.
[0036] In some embodiments, the plateau period defines multiple calculation windows (e.g., multiple candidate calculation windows). In some embodiments, the multiple calculation windows include a first calculation window, such as a first calculation window 330A, and a second calculation window 330B. In some embodiments, as shown in Figure 3, the first calculation window 330A has a length shorter than the length of the plateau period, and the second calculation window 330B has a length substantially equal to the length of the plateau period. In this regard, the first calculation window 330A has a length shorter than the length of the second calculation window.
[0037] In some embodiments, the controller 116 is configured to determine the operating conditions associated with the fluxgate current sensor 100 and to select a calculation window from a plurality of calculation windows based on the operating conditions. In some embodiments, the operating conditions refer to the primary current signal type of the current being measured (e.g., DC primary current or AC primary current). For example, a DC operating condition may indicate a DC primary current signal, and an AC operating condition may indicate an AC primary current signal.
[0038] In some embodiments, the controller 116 is configured to select a first calculation window in response to determining that a signal is an interference signal. In some embodiments, the controller 116 is configured to select a first calculation window in response to determining that the operating conditions are DC operating conditions, and to select a second calculation window in response to determining that the operating conditions are AC operating conditions. For example, the fluxgate signal (e.g., its sampling value) may change minimally during the plateau periods 210A, 210B of the DC fluxgate signal waveform 300A such that the length of the calculation window has little to no significant effect on the calculated current value when the primary current signal is a DC primary current. For example, during the plateau periods 210A, 210B of the DC fluxgate signal waveform 300A, the interference signal may be coupled to the saturated-unsaturated region 204A~C (e.g., indicating an unstable region). Furthermore, interference immunity may be improved for DC operating conditions with a short calculation window without affecting the accuracy of the calculated current value (e.g., the calculated value of the primary current).
[0039] On the other hand, the fluxgate signal can change significantly during the plateau periods 210A and 210B of the AC fluxgate signal waveform 300B, and as a result, the calculation window has a significant impact on the calculated current value. For example, a calculation window that excludes region 320 within the plateau period may result in an inaccurate calculated current value. For instance, the average of the signal in region 320 is not included in the calculated current value, and therefore, signal fluctuations in region 320 are not reflected in the calculated current value, affecting the accuracy of the calculated current value.
[0040] In some embodiments, the controller 116 uses a classification model and also based on a set of signal characteristics to determine the operating condition classification. In some embodiments, the classification model is a rule-based model. For example, in some embodiments, the classification model includes a set of rules. Each rule may include one or more rule conditions, which are at least partially defined by one or more characteristics of the fluxgate signal within a plateau period (and / or associated platform period) and a corresponding threshold.
[0041] In some embodiments, the controller 116 generates a signal characteristics set by performing an analysis on the fluxgate signal. In some embodiments, performing an analysis on the fluxgate signal includes extracting data from the fluxgate signal and analyzing and / or processing the extracted data. In some embodiments, the fluxgate signal and / or the extracted data may be applied to one or more analysis models to generate a signal characteristics set. In some embodiments, the analysis model may include one or more mathematical models.
[0042] In some embodiments, the signal characteristics set includes peak signal data, signal dispersion data, and cycle data. In some embodiments, the peak signal data includes the peak values for the first and / or second plateau periods (e.g., the peak value P1 for the first plateau period 210A and / or the peak value P2 for the second plateau period 210B). In some embodiments, the signal dispersion data includes the dispersion values for the first and / or second plateau periods (e.g., the dispersion V1 for the first plateau period 210A and / or the dispersion V2 for the second plateau period 210B). In some embodiments, the cycle data includes the number of cycles for the first and / or second plateau periods (e.g., the number of signal cycles for the first plateau period 210A and / or the number of signal cycles C2 for the second plateau period 210B).
[0043] For example, the peak value of the DC fluxgate signal within plateau periods 210A and 210B may be smaller than the peak value of the AC fluxgate signal within plateau periods 210A and 210B, and conversely, the peak value of the AC fluxgate signal within plateau periods 210A and 210B may be larger than the peak value of the DC fluxgate signal within plateau periods 210A and 210B. Furthermore, the variance (e.g., measure of variation) of the DC fluxgate signal within plateau periods 210A and 210B may be smaller than the peak value of the AC fluxgate signal within plateau periods 210A and 210B, and conversely, the variance of the AC fluxgate signal within plateau periods 210A and 210B may be larger than the variance of the DC fluxgate signal within plateau periods 210A and 210B. Furthermore, the amplitude of the AC fluxgate signal (e.g., an AC sampled signal) may change periodically, and the number of cycles per unit length platform period may correspond to the primary signal period.
[0044] In some embodiments, one or more rule conditions include a first condition that evaluates the respective peak values (P1, P2) of the first plateau period 210A and the second plateau period 210B against a threshold P to determine whether the respective peak values are greater than the threshold P. In some embodiments, one or more rule conditions include a second condition that evaluates the respective variance values (V1, V2) of the first plateau period 210A and the second plateau period 210B against a threshold V to determine whether the variance is greater than the threshold V. In some embodiments, one or more rule conditions include a third condition that evaluates the respective cycle data (C1, C2) of the first plateau period 210A and the plateau period 210B against a threshold C to determine whether the cycle data is greater than the threshold C.
[0045] In some embodiments, the controller 116 is configured to determine that the fluxgate signal is an interference signal in response to determining that at least two of the rule conditions are met. For example, the fluxgate signal may be asymmetric when at least two of the rule conditions indicating an interference signal are met. In some embodiments, the controller 116 is configured to determine that the fluxgate signal is a stable signal in response to determining that none of the rule conditions are met.
[0046] In some embodiments, the controller 116 is configured to generate a DC operating classification (e.g., classify the operating condition as a DC operating condition) in response to determining that each of the first and second conditions is not met (e.g., using a classification model). For example, the controller may determine that the operating condition is a DC operating condition (e.g., indicating a DC primary signal) in response to determining that the peak value during a plateau period (e.g., a first and / or second plateau period) is less than the corresponding peak threshold and the variance during a plateau period (e.g., a first and / or second plateau period) is less than the corresponding variance threshold. In some embodiments, the controller 116 may be configured to first determine whether the fluxgate signal is stable before generating a DC operating classification.
[0047] In some embodiments, the controller 116 is configured to generate an AC operating condition classification (e.g., classify the operating condition as an AC operating condition) in response to determining that at least one of the first or second conditions is met (e.g., using a classification model). For example, the controller 116 may determine that the operating condition is an AC operating condition (e.g., indicating an AC primary signal) in response to determining that the peak value during a plateau period (e.g., a first and / or second plateau period) is greater than the corresponding peak threshold, or that the variance during a plateau period (e.g., a first and / or second plateau period) is greater than the corresponding variance threshold.
[0048] In some embodiments, a predetermined minimum number of sampling times are accumulated for switching between DC and AC operating conditions to avoid accidental variations that may affect the classification of operating conditions. As shown in Figure 5, for example, multiple signals 504A-E of different frequencies may be utilized.
[0049] In some embodiments, the controller 116 is configured to calculate the value of the primary current by performing the following calculation in equation 1.
[0050]
number
[0051] In equation 1, I p This may represent the calculated current value of the primary current.
[0052]
number
[0053] [Number] may represent the average current value in the selected calculation window of the second plateau period 210B, Σ plateau 2 may represent the sum of the sampled current values within the selected calculation window of the first plateau period, count プラトー2 may represent the size of the calculation window during the platform period associated with the second plateau period.
[0054] In some embodiments, the controller 116 calculates count プラトー1 by performing the operation of Equation 2 below, and calculates count プラトー2 by performing the operation of Equation 3 below. Count プラトー1 = ratio * Plateau 1 length Equation 2 Count プラトー2 = ratio * Plateau 2 length Equation 3
[0055] In Equations 2 and above, count プラトー1 and count プラトー2 may each represent the calculation window during the platform period associated with the first plateau and the calculation window during the platform period associated with the second plateau, respectively. In some embodiments, the ratios in Equations 2 and above are constant with respect to the DC primary current. In some embodiments, the controller 116 is configured to calculate the ratios of Equations 2 and with respect to the AC primary current by performing the operation of Equation 4 below.
[0056] [Number] In the formula, a may represent the gain, b may represent the offset, C1 may represent the number of cycles per unit-length platform period associated with the first plateau period and corresponding to the signal cycle of the primary current, and C2 may represent the number of cycles per unit-length platform period associated with the second plateau period and corresponding to the signal cycle of the primary current. For example, the plateau under AC operating conditions (e.g., under an AC signal) may be dynamically adjusted using the signal cycle of the primary current.
[0057] Figure 4 shows a flowchart illustrating the operation of an exemplary method for measuring current using a fluxgate current sensor, according to at least one embodiment. In particular, Figure 4 shows an exemplary method 400 for an improved fluxgate current sensor under AC operating conditions. In some embodiments, method 400 is carried out by one or more specially configured computing devices, such as an apparatus that embodies a fluxgate current sensor, either alone or in communication with one or more other components, devices, systems, etc. In some embodiments, the apparatus comprises a fluxgate current sensor 100. In some embodiments, the apparatus communicates with one or more external devices, systems, etc. to perform one or more operations as illustrated and described.
[0058] While exemplary Method 400 illustrates a specific sequence of operations, the sequence may be modified without departing from the scope of the disclosure. For example, some of the illustrated operations may be performed in parallel or in different sequences that do not substantially affect the functionality of Method 400. In other examples, different components of the exemplary device or system that implement Method 400 may perform their functions substantially simultaneously or in a specific sequence.
[0059] According to some examples, method 400 includes receiving a fluxgate signal in block 402. For example, controller 116 may receive a fluxgate signal from the fluxgate excitation and sampling module of fluxgate current sensor 100. The fluxgate excitation and sampling module may include a fluxgate oscillator circuit (e.g., an H-bridge), a sampling resistor, an amplifier, and / or an ADC. The fluxgate signal may correspond to a primary current and may include at least two plateau periods. Each of the at least two plateau periods may define a plurality of candidate calculation windows. In some embodiments, the calculation window refers to a portion of the fluxgate signal that includes a sampled signal (e.g., representing a sampled current).
[0060] According to some examples, method 400 includes generating a signal characteristic set in block 404. For example, controller 116 may generate a signal characteristic set based on a fluxgate signal by performing an analysis on the fluxgate signal. In some embodiments, performing an analysis on a fluxgate signal includes extracting data from the fluxgate signal and analyzing and / or processing the extracted data. In some embodiments, the fluxgate signal and / or the extracted data may be applied to one or more analytical models to generate a signal characteristic set. In some embodiments, the analytical model may include one or more mathematical models.
[0061] In some embodiments, the signal characteristics set includes peak signal data, signal dispersion data, and cycle data. In some embodiments, the signal characteristics set includes peak signal data, signal dispersion data, and cycle data. In some embodiments, the peak signal data includes peak values for the first and second plateau periods (e.g., peak value P1 for the first plateau period and / or peak value P2 for the second plateau period). In some embodiments, the signal dispersion data includes dispersion values for the first plateau period (e.g., dispersion V1 for the first plateau period and / or dispersion V2 for the second plateau period). In some embodiments, the cycle data includes the number of cycles for the first and second plateau periods (e.g., number of signal cycles for the first plateau period and / or number of signal cycles C2 for the second plateau period).
[0062] In some examples, method 400 includes generating an operating condition classification in block 404. For example, controller 116 may generate an operating condition classification based on a signal characteristic set by applying the signal characteristic set to a classification model. In some embodiments, the operating condition is one of either an AC operating condition indicating an AC primary current or a DC operating condition indicating a DC primary current. In some embodiments, the classification model is a rule-based model that includes multiple rules. In some embodiments, generating an operating condition classification includes comparing the signal characteristic set with one or more thresholds.
[0063] In some embodiments, generating an operating condition classification includes determining whether (i) the peak signal data meets the peak threshold, (ii) the variance data meets the variance threshold, and / or (iii) the cycle data meets the cycle threshold. In some embodiments, generating an operating condition classification includes generating the operating condition classification as a DC operating condition classification in response to determining that (i) the peak value data does not meet the peak threshold and (ii) the variance data does not meet the variance threshold. In some embodiments, generating an operating condition classification includes generating the operating condition classification as an AC operating condition classification in response to determining that (i) the peak value data meets the peak threshold, or (ii) the variance data meets the variance threshold.
[0064] In some embodiments, peak signal data does not meet the peak threshold if the peak value during a plateau period (e.g., the first and / or second plateau period) is less than the corresponding peak threshold. In some embodiments, variance data does not meet the variance threshold if the variance during a plateau period (e.g., the first and / or second plateau period) is less than the corresponding variance threshold.
[0065] In some embodiments, peak signal data satisfies the peak threshold if the peak value during a plateau period (e.g., a first and / or second plateau period) is greater than the corresponding peak threshold. In some embodiments, variance data satisfies the variance threshold if the variance during a plateau period (e.g., a first and / or second plateau period) is greater than the corresponding variance threshold.
[0066] According to some examples, method 400 includes selecting a calculation window in block 406. For example, controller 116 may select a calculation window from a plurality of calculation windows based on an operating condition classification. For example, the calculation windows may be dynamically changed according to different operating conditions. In some embodiments, the plurality of calculation windows include a first calculation window and a second calculation window. In some embodiments, selecting a calculation window from a plurality of calculation windows based on an operating condition classification includes selecting a first calculation window in response to a DC operating condition classification. In some embodiments, selecting a calculation window from a plurality of calculation windows based on an operating condition classification includes selecting a second calculation window in response to an AC operating condition classification. In some embodiments, the first calculation window has a length shorter than the length of the second calculation window. In some embodiments, the first calculation window has a length shorter than the length of each of at least two plateau periods.
[0067] According to some examples, method 400 includes generating a predicted current value for the primary current in block 408. For example, controller 116 may generate a predicted current value for the primary current by applying sampled current values in a selected calculation window to a prediction model for each of at least two plateau periods. In some embodiments, generating a predicted current value includes generating an average of the sampled current values. For example, controller 116 may perform the operation shown in equation 1 above. In some embodiments, the prediction model may define the operation of equation 1.
[0068] Conclusion: Many modifications and other embodiments of the Disclosure described herein will be conceived by those skilled in the art who are interested in this Disclosure and who have an interest in the teachings presented in the foregoing description and the accompanying drawings. Therefore, it should be understood that embodiments are not limited to any particular embodiment disclosed, and that modifications and other embodiments are intended to be included within the scope of the appended claims. Furthermore, while the foregoing description and the accompanying drawings illustrate exemplary embodiments in the context of certain exemplary combinations of elements and / or functions, it should be understood that different combinations of elements and / or functions may be provided by alternative embodiments without departing from the scope of the appended claims. In this regard, for example, other combinations of elements and / or functions different from those specified above are intended to be included within the scope of the appended claims. Certain terms are used herein, but these are used in a general and descriptive sense only and not for limiting purposes.
[0069] This specification includes many specific implementation details, but these should not be construed as limiting the scope of any disclosure or claim, but rather as descriptions of features specific to particular embodiments of a particular disclosure. Certain features described herein in the context of a separate embodiment may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented separately or in any preferred subcombination in numerous embodiments. Furthermore, even if features are described above as acting in a particular combination and initially claimed to do so, one or more features from a claimed combination may, in some cases, be removed from the combination, and the claimed combination may be directed towards a subcombination or a variation of a subcombination.
[0070] Similarly, while operations are shown in a specific order in the drawings, this should not be understood as requiring that such operations be performed in a specific order or sequence shown, or that all shown operations be performed, in order to achieve the desired result. In certain circumstances, multitasking and parallel processing may be advantageous. Furthermore, the separation of various system components in the embodiments described above should not be understood as requiring such separation in all embodiments, and it should be understood that the described program components and systems can generally be integrated into a single software product or packaged into multiple software products.
[0071] Accordingly, specific embodiments of this subject matter have been described. Other embodiments are within the scope of the following claims. In some cases, the actions enumerated in the claims may be performed in a different order and the desired results may still be achieved. In addition, the processes shown in the accompanying drawings do not necessarily require the specific illustrated order or sequential order to achieve the desired results. In certain implementations, multitasking and parallel processing may be advantageous.
[0072] Furthermore, while this detailed description outlines several embodiments of the present disclosure, the appended claims may, in accordance with various modifications and improvements, encompass other embodiments of the present disclosure different from those described. Moreover, unless the specific terms “means for” or “steps for” are used in a given claim within the appended claims, that claim is not intended to be construed under Section 112, paragraph (f) of the United States Patent Act.
Claims
1. A method for measuring current using a fluxgate current sensor, wherein the method is The controller receives a fluxgate signal corresponding to the primary current, wherein the fluxgate signal includes at least two plateau periods, each plateau period defining a plurality of candidate calculation windows. The controller generates an operating condition classification based on the signal characteristic set by applying the signal characteristic set to a classification model, wherein the operating condition classification is one of (i) an AC operating condition indicating an AC primary current, or (ii) a DC operating condition indicating a DC primary current. The controller selects a calculation window from a plurality of calculation windows based on the classification of operating conditions, wherein the plurality of calculation windows include a first calculation window and a second calculation window. A method comprising: generating a predicted current value for the primary current by applying the sampled current values in the selected calculation window to a prediction model for each of the at least two plateau periods using the controller, wherein generating the predicted current value includes generating an average of the sampled current values.
2. The method according to claim 1, wherein the fluxgate signal is received from a fluxgate excitation and sampling module.
3. The method according to claim 1, further comprising performing an analysis on the flux-gate signal to generate the signal characteristic set based on the flux-gate signal.