Self-calibrating current sensor

Abstract

To provide a current sensor configuration element, device, and method for self calibration.SOLUTION: A self calibration current measuring device 300 includes a low-range current sensor 302 configured to generate a first voltage signal, a high-range current sensor 304 configured to generate a second voltage signal, and a self calibration current measuring circuit 320. The self calibration current measuring circuit is configured to: receive the first voltage signal and the second voltage signal; convert the first voltage signal and the second voltage signal into a first digital signal and a second digital signal, respectively; compare the first digital signal with the second digital signal; based on the comparison, determine that a difference between the first voltage signal and the second voltage signal exceeds a re-calibration threshold value; based on the determination, generate calibration data; and, based on application of the calibration data to the second digital signal, generate a digital output signal indicating a current reading value.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] FIELD Exemplary embodiments of the present disclosure relate generally to current sensors, and more particularly to a current sensor apparatus and method for self-calibration thereof. [Background technology]

[0002] Current sensors are used in many industrial and automotive applications, such as battery management systems. It is important to incorporate accurate sensors into battery monitoring systems to obtain detailed information about the battery's state of health and state of charge. Current sensors may be used to measure the current flowing into the battery (when charging) and the current flowing out of the battery (when discharging). Applicant has recognized many technical challenges and difficulties associated with conventional current sensors. Summary of the Invention

[0003] Various embodiments described herein relate to current sensor components, devices, and methods for self-calibration.

[0004] According to various embodiments of the present disclosure, a self-calibrating current measurement device is provided. In some embodiments, the components include a low-range current sensor configured to generate a first voltage signal, a high-range current sensor configured to generate a second voltage signal, and a self-calibrating current measurement circuit configured to receive the first and second voltage signals, convert the first and second voltage signals to respective first and second digital signals, compare the first digital signal to the second digital signal, determine based on the comparison that a difference between the first and second digital signals exceeds a recalibration threshold, generate calibration data based on the determination, and generate a digital output signal representative of a current reading based on application of the calibration data to the second digital signal.

[0005] In some embodiments, the self-calibrating current measurement device further comprises a communication module configured to receive a digital output and transmit the digital output to a battery management system. In some embodiments, the low-range current sensor includes a closed-loop current sensor or a fluxgate current sensor. In some embodiments, the high-range current sensor includes an open-loop current sensor.

[0006] According to another embodiment, a method for evaluating current sensor performance is provided. In some embodiments, the method includes receiving, by a computing device, a first current sensor signal and a second current sensor signal. In some embodiments, the method further includes determining, by the computing device, a difference between the first current sensor signal and the second current sensor signal in relation to a current reading. In some embodiments, the method further includes comparing, by the computing device, the difference to a recalibration threshold. In some embodiments, the method further includes recalibrating, by the computing device, the current sensor based on a determination that the difference is greater than the recalibration threshold.

[0007] In some embodiments, recalibrating the current sensor further includes generating calibration data based on a difference and applying the calibration data to the measured current sensor. In some embodiments, the current sensor is associated with a second current sensor signal. In some embodiments, the first current sensor signal includes a digitized analog output voltage signal generated by the first current sensor. In some embodiments, the first current sensor includes a low-range current sensor. In some embodiments, the second current sensor signal includes a digitized analog output voltage signal generated by the second current sensor. In some embodiments, the second current sensor includes a high-range current sensor. In some embodiments, the recalibration threshold includes a fixed threshold for a range of current readings. In some embodiments, the recalibration threshold includes a plurality of thresholds for a range of current readings. In some embodiments, the method further includes comparing the difference to a recalibration threshold associated with the current reading.

[0008] According to another embodiment, a method for performing current sensor self-calibration is provided. In some embodiments, the method includes receiving, by a computing device, first channel data and second channel data. In some embodiments, the method further includes comparing, by the computing device, a difference between the first channel data and the second channel data to a recalibration threshold. In some embodiments, the method further includes generating, by the computing device, new calibration data based on a determination that the difference is greater than the recalibration threshold. In some embodiments, the method further includes applying, by the computing device, the new calibration data to the second channel data. In some embodiments, the method further includes generating, by the computing device, a current reading based on the second channel data and the application of the new calibration data. In some embodiments, the method further includes determining that the first channel data and the second channel data are associated with measurements of current within a low range.

[0009] In some embodiments, the method further includes determining that the first channel data and the second channel data are not associated with measured values of current within a low range, determining generation of new calibration data, retrieving current calibration data based on the determination of generation of new calibration data and applying it to the second channel data, and generating a current reading value based on the second channel data and the application of the current calibration data. In some embodiments, the method further includes determining that the first channel data and the second channel data are not associated with measured values of current within a low range, retrieving previous calibration data and applying it to the second channel data, and generating a current reading value based on the second channel data and the application of the previous calibration data. In some embodiments, the method further includes assigning new calibration data as current calibration data and assigning calibration data generated prior to the new calibration data as previous calibration data. In some embodiments, the new calibration data includes a linear transformation or a segmented mapping based on the first channel data or a difference.

[0010] The foregoing example summary, as well as other exemplary objects and / or advantages of the present disclosure, and the manner in which they are achieved, are further described in the following detailed description of the invention and its accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The description of the illustrated embodiments can be read in conjunction with the accompanying drawings. It will be understood that, unless otherwise specified, the elements shown in the drawings are not necessarily drawn to scale for the sake of simplicity and clarity. For example, unless otherwise specified, the dimensions of some of the elements may be exaggerated relative to other elements. Embodiments incorporating the teachings of the present disclosure are shown and described in relation to the figures presented herein.

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DETAILED DESCRIPTION OF THE INVENTION

[0012] Next, some embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings, which show some, but not all, embodiments of the present disclosure. In fact, the present disclosure may be embodied in many different forms and should not be construed as limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout.

[0013] 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 element or related description being referred to is accurate within applicable engineering tolerances.

[0014] As used herein, the term "comprising" means including, but not limited to, and should be construed in the manner typically used in the patent context. It should be understood that the use of broader terms such as "comprises", "includes", and "having" supports the use of narrower terms such as "consisting of", "consisting essentially of", and "comprised substantially of".

[0015] The phrases "in one embodiment", "according to one embodiment", and similar phrases generally mean that the particular feature, structure, or characteristic following such phrases can be included in at least one embodiment of the present disclosure and can be included in more than one embodiment of the present disclosure (importantly, such phrases do not necessarily refer to the same embodiment).

[0016] As used herein, the word "example" or "exemplary" means "serving as an example, instance, or illustration". Any implementation described herein as "exemplary" should not necessarily be construed as being more preferred or advantageous than other implementations.

[0017] When this specification states that a component or feature "may be included", "can include", "could include", "should include", "would include", "preferably includes", "optionally includes", "typically includes", "optionally includes", "for example includes", "often includes" or "may include" (or other such language), or presents having a certain property, that particular component or feature is not necessarily required to be included or to have that property. Such a component or feature may optionally be included or excluded in some embodiments.

[0018] Along with electronic devices and semiconductor devices, current sensors are widely used to measure the operating current in power systems such as the battery systems of electric vehicles. However, there are many technical problems and difficulties associated with current sensors. A current sensor may comprise a device used to measure the flow of current in an electrical circuit. A current sensor may comprise either an open-loop circuit or a closed-loop circuit used to measure the current flowing through a conductor. Open-loop current sensors offer various advantages such as low cost, low power consumption, and a simple structure.

[0019] Referring now to FIG. 1, a system architecture of an open-loop current sensor 100 that can be used according to various embodiments of the present disclosure is provided. The open-loop current sensor 100 can be used for the detection of current by indirect sensing. As shown in FIG. 1, the open-loop current sensor 100 comprises a magnetic core 104. The magnetic core 104 may include a ferromagnetic material such as a nanocrystalline and permalloy material.

[0020] The magnetic core 104 may comprise a ring-shaped object and an opening including a cavity within the inner circumference of the magnetic core 104. The opening may be configured to detect current by indirect sensing. For example, a conductor 120 carrying current may be disposed through the opening formed by the magnetic core 104 of the open-loop current sensor 100. The conductor 120 may comprise a bus bar comprising a metal bar or strip used to carry or transmit current.

[0021] The magnetic core 104 further includes a gap in which a magnetic transducer 106 such as a Hall effect sensor is disposed. The magnetic transducer 106 can generate an output voltage in response to the magnetic flux induced by the current in the conductor 120 within the opening formed by the magnetic core 104. The current carried by the conductor 102 can generate a magnetic flux that can induce an electromotive force (EMF) measured by a voltage in accordance with Faraday's law of electromagnetic induction. The EMF can induce a current flow on the magnetic core 104. Thus, the magnetic transducer 106 can output a Hall voltage proportional to the current flow in the magnetic core. The amplifier 108 can amplify the voltage from the magnetic transducer 106 to generate an output voltage Vout112. Vout112 can be taken directly from the amplifier 108 to obtain a voltage signal representing the current measurement value.

[0022] An open-loop current sensor, such as the open-loop current sensor 100 illustrated in FIG. 1, includes a technique for detecting a current on a conductor (e.g., conductor 120) and has advantages such as low cost, low power consumption, and a simple structure. However, the performance (e.g., linearity) of an open-loop current sensor is affected by magnetic hysteresis and environmental factors such as humidity and temperature, which can cause zero drift and changes in magnetic transducer sensitivity. Therefore, it can be difficult to achieve the accuracy of an open-loop current sensor due to the saturation effect and non-linearity caused by humidity / temperature.

[0023] FIG. 2 is a graph illustrating exemplary losses in the performance of an open-loop current sensor showing linearity drift. An open-loop current sensor with linearity drift can prevent accurate measurement values from being obtained, but may benefit from recalibration. However, another major drawback of an open-loop current sensor is that recalibration can only be performed in a laboratory (e.g., by the manufacturer).

[0024] Other types of sensors, such as closed-loop current sensors, can be used as an alternative to open-loop current sensors. For example, unlike open-loop current sensors, closed-loop current sensors are resistant to linearity drift of sensor sensitivity and provide higher measurement accuracy. A closed-loop current sensor may comprise components similar to an open-loop current sensor with an additional wire coil wound around a magnetic core. The wire coil can be driven by the detected voltage of the conductor (e.g., Vout112) to send opposing currents through the wire coil to create a flux balance that cancels out the magnetic flux generated by the conductor current. By balancing in this way, the effects of temperature / humidity and saturation can be eliminated, enabling more accurate measurements. A fluxgate current sensor is also similar to a closed-loop current sensor in operation, but instead of a Hall effect sensor, a saturable inductor using a small and thin magnetic core may be used to detect the air gap field. However, the added complexity of either a closed-loop current sensor or a fluxgate current sensor leads to higher costs. Therefore, closed-loop current sensors and fluxgate current sensors are typically more accurate than open-loop current sensors but are costly.

[0025] Various exemplary embodiments of the present disclosure overcome such technical problems and difficulties in current sensors and provide various technical advancements and improvements. Specifically, a multi-sensor current measurement device and a self-calibration method are disclosed herein. The multi-sensor current measurement device may comprise a plurality of current sensors with complementary capabilities such that the advantages provided by each current sensor are utilized by the coexistence of the plurality of current sensors within a single device. In some embodiments, the multi-sensor current measurement device may comprise a calibration current sensor and a measurement current sensor. The measurement value obtained by the measurement current sensor can be mainly provided as a measurement current reading, and the measurement value obtained by the calibration current sensor can be provided as a measurement current reading and serve as a measurement reference for the measurement current sensor to determine whether calibration of the measurement current sensor is required and the accuracy of the measurement current sensor.

[0026] FIG. 3 presents an exemplary schematic diagram of a self - calibrating current measurement device according to various embodiments described herein. The self - calibrating current measurement device 300 includes a low - range current sensor 302 and a high - range current sensor 304. That is, the self - calibrating current measurement device 300 can simultaneously use a combination of current sensors (e.g., having complementary capabilities) within a single device. To prevent mutual interference, the low - range current sensor 302 and the high - range current sensor 304 can be configured such that at least one magnetic transducer / inductor of the low - range current sensor 302 or the high - range current sensor 304 is separated, covered, or otherwise shielded.

[0027] In some embodiments, the low - range current sensor 302 can include a closed - loop current sensor or a flux - gate current sensor, and the high - range current sensor 304 can include an open - loop current sensor. As described above, an open - loop current sensor (e.g., the high - range current sensor 304) can be affected by magnetic hysteresis and environmental factors that affect measurement accuracy, while a closed - loop current sensor or a flux - gate current sensor (e.g., the low - range current sensor 302) can be resistant to such effects and can potentially provide a relatively more stable and reliable current measurement value. According to various embodiments of the present disclosure, the self - calibrating current measurement device 300 can selectively use the low - range current sensor 302 and the high - range current sensor 304 for a particular function based on their device capabilities. For example, since the measurement range of the high - range current sensor 304 is wider than that of the low - range current sensor 302, it may be used to generate a current reading value, while the low - range current sensor 302, which can measure current with higher accuracy than the high - range current sensor 304, may be used to provide a reference measurement value for calibrating the current measurement value of the high - range current sensor 304.

[0028] The low-range current sensor 302 may include a current sensor capable of measuring a current in a first range with a first amount of accuracy. The high-range current sensor 304 may include a current sensor capable of measuring a current in a second range with a second amount of accuracy. According to various embodiments of the present disclosure, the first range of the current may be smaller than the second range of the current, and the first amount of accuracy may be greater than the second amount of accuracy. Thus, the low-range current sensor 302 may be capable of (i) measuring a range of current values that is smaller than the measurement range of the high-range current sensor 304, and (ii) measuring the current with a higher accuracy than the high-range current sensor 304. Conversely, the high-range current sensor 304 may be capable of (i) measuring a range of current values that is larger than the measurement range of the low-range current sensor 302, and (ii) measuring the current with a lower accuracy than the low-range current sensor 302.

[0029] In some embodiments, when the current being measured is within the measurement ranges of both the low-range current sensor 302 and the high-range current sensor 304, the low-range current sensor 302 and the high-range current sensor 304 may be used simultaneously to measure the current. For example, the low-range current sensor 302 may be capable of measuring a current in a range of approximately 0 to 300 A, while the high-range current sensor 304 may be capable of measuring a current in a range (e.g., an upper limit, a lower limit, or both) that is larger than the measurement range of the low-range current sensor 302, e.g., a current of approximately 50 to 600 A. Thus, according to a given example, the low-range current sensor 302 and the high-range current sensor 304 may be used simultaneously to measure the current for current values within a range of approximately 50 to 300 A. In some other embodiments, the low-range current sensor 302 may be capable of measuring a current in a range of approximately -300 A to 300 A, and the high-range current sensor 304 may be capable of measuring a current in a range of approximately -1500 A to 1500 A.

[0030] The low-range current sensor 302 and the high-range current sensor 304 may include a measurement path through, aperture, or detection region configured to receive, conduct, or sense magnetic flux generated by a current-carrying conductor (e.g., a wire, cable, or bus). The induced magnetic flux may be detected by respective magnetic transducers of the low-range current sensor 302 and the high-range current sensor 304. The low-range current sensor 302 and the high-range current sensor 304 may generate an analog output voltage signal based on (e.g., proportional to) the induced magnetic flux. The analog output voltage signals generated by the low-range current sensor 302 and the high-range current sensor 304 may be transmitted to the self-calibrating current measurement circuit 320.

[0031] According to various embodiments of the present disclosure, the self-calibrating current measurement circuit 320 may use the analog output voltage signals from the low-range current sensor 302 and the high-range current sensor 304 to generate a current reading and perform self-calibration. The current reading may be generated based on a voltage signal from at least one of the low-range current sensor 302 or the high-range current sensor 304. In some embodiments, the current reading may be based on a voltage signal from the high-range current sensor 304, and the voltage signal from the low-range current sensor 302 may be used as a reference for calibrating the high-range current sensor 304. For example, to detect a linearity drift of the high-range current sensor 304, the voltage signal from the low-range current sensor 302 may be compared to the voltage signal from the high-range current sensor 304.

[0032] The self-calibrating current measurement circuit 320 includes a regulator circuit 306, an analog-to-digital converter (ADC) 308, a microcontroller unit (MCU) 310, a communication module 312, and a power supply voltage regulator 314. The low-range current sensor 302 and the high-range current sensor 304 are coupled to the regulator circuit 306 via channels. In some embodiments, a channel as disclosed herein refers to a physical transmission medium such as a wire, cable, or link, and an interface dedicated to transferring signals from a particular source. The analog output voltage signals (e.g., Vout) from the low-range current sensor 302 and the high-range current sensor 304 can be transmitted to the regulator circuit 306 using their respective channels. For example, the first channel may be designated to transmit the analog output voltage signal from the low-range current sensor 302 to the regulator circuit 306, and the second channel may be designated to transmit the analog output voltage signal from the high-range current sensor 304 to the regulator circuit 306. Thus, the source of the signal received by the regulator circuit 306 can be identified by the channel through which the signal is received.

[0033] The regulator circuit 306 may include an electronic component or circuit component configured to adjust the analog voltages received from the low-range current sensor 302 and the high-range current sensor 304 to prevent overvoltage (e.g., a voltage exceeding the limits of the self-calibrating current measurement circuit 320). For example, the regulator circuit 306 can protect the self-calibrating current measurement circuit 320 from overvoltage by supplying an adjusted voltage when the voltage received from either the low-range current sensor 302 or the high-range current sensor 304 exceeds a threshold voltage. The regulator circuit 306 can pass the adjusted analog voltages associated with the low-range current sensor 302 and the high-range current sensor 304 to an analog-to-digital converter (ADC) 308.

[0034] ADC308 may include one or more circuit components or electronic components configured to convert an analog voltage into a digital number representing the magnitude of the analog voltage. For example, ADC308 may convert a continuous-time and continuous-amplitude analog signal into a discrete-time and discrete-amplitude digital signal. According to various embodiments of the present disclosure, the self-calibrating current measurement circuit 320 may use ADC308 to convert the adjusted analog output voltage signals associated with the low-range current sensor 302 and the high-range current sensor 304 into respective digital signals for processing by the microcontroller unit (MCU) 310. For example, the MCU 310 may process a first digital input signal representing the analog output voltage signal associated with the low-range current sensor 302 and a second digital input signal representing the analog output voltage signal associated with the high-range current sensor 304 to generate a digital output signal including a current reading. The current reading may be an estimated current of the current-carrying conductor that can be calculated based on the conversion of the digital input signal associated with at least one of the low-range current sensor 302 or the high-range current sensor 304. In some embodiments, the digital output signal may be generated using only the digital input signal of the high-range current sensor 304, for example, when the measured current is outside the measurement range of the low-range current sensor 302.

[0035] The MCU 310 can further compare a first digital input signal representing an analog output voltage signal associated with the low-range current sensor 302 with a second digital input signal representing an analog output voltage signal associated with the high-range current sensor 304 to determine whether calibration of the high-range current sensor 304 is necessary. For example, the MCU 310 monitors the difference between a first digital input signal representing an analog output voltage signal associated with the low-range current sensor 302 and a second digital input signal representing an analog output voltage signal associated with the high-range current sensor 304, and can determine when the monitored difference exceeds a recalibration threshold. In some embodiments, when the difference does not exceed the recalibration threshold, a digital output signal including a current reading value is generated based on at least one of the first digital input signal or the second digital input signal. In some additional embodiments, when the difference exceeds the recalibration threshold, a self-recalibration method is performed to generate calibration data, which is described in more detail with respect to the description of FIG. 7. The calibration data can describe a conversion function or mapping used to align data from the measured current sensor with data from the calibrated current sensor, as disclosed herein. In some embodiments, the calibration data can be applied to the second digital input signal to generate, for example, a digital output signal that reflects a measurement value by the high-range current sensor 304 calibrated based on the first digital input signal associated with the low-range current sensor 302.

[0036] The MCU 310 may include processing elements embodied as one or more complex programmable logic devices (CPLDs), microprocessors, multi-core processors, coprocessing entities, application-specific instruction-set processors (ASIPs), microcontrollers, and / or controllers. Further, the MCU 310 may be embodied as one or more other processing devices or processing circuits. The term circuit may refer to an all-hardware embodiment or a combination of hardware and a computer program product. Thus, the MCU 310 may be embodied as an integrated circuit, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a programmable logic array (PLA), a hardware accelerator, other circuits, and / or the like.

[0037] Accordingly, as will be appreciated, the MCU 310 may be configured for a particular use or may execute instructions stored in a volatile or non-volatile medium or otherwise accessible to the MCU 310. Thus, whether configured by hardware or a computer program product or a combination thereof, the MCU 310 may be capable of performing steps or operations in accordance with embodiments of the present invention when configured accordingly.

[0038] The digital output signal generated by the MCU 310 can be communicated to various computing entities for communication by the communication module 312, for example, by communicating data including a digital output signal representing a measured current of a current-carrying conductor that can transmit, receive, operate, process, display, store, etc. In some embodiments, the communication module 312 may comprise a controller area network (CAN) transceiver configured to communicate with one or more components within a vehicle, such as a battery management system. In some other embodiments, the communication module 312 may be able to transmit and receive data according to the air interface standards of an applicable wireless system. In this regard, the self-calibrating current measurement device 300 may be capable of operating with one or more air interface standards, communication protocols, modulation types, and access types. More specifically, the self-calibrating current measurement device 300 may operate according to any of several wireless communication standards and protocols, such as those described above with respect to the predictive data analysis computing entity 106. In some embodiments, the self-calibrating current measurement device 300 may operate according to multiple wireless communication standards and protocols such as UMTS, CDMA2000, 1xRTT, WCDMA, GSM, EDGE, TD-SCDMA, LTE, E-UTRAN, EVDO, HSPA, HSDPA, Wi-Fi, Wi-Fi Direct, WiMAX, UWB, IR, NFC, Bluetooth, USB, and / or the like.Similarly, in some alternative embodiments, the self-calibrating current measurement device 300 can operate according to multiple wired communication standards and protocols such as fiber distributed data interface (FDDI), digital subscriber line (DSL), Ethernet, asynchronous transfer mode (ATM), frame relay, data over cable service interface specification (DOCSIS), or any other wired transmission protocol.

[0039] The power supply voltage regulator 314 can include one or more circuit components or electronic components configured to provide a relatively stable supply voltage to the components of the self-calibrating current measurement circuit 320 (the regulator circuit 306, the ADC 308, the MCU 310, and the communication module 312). For example, the power supply voltage regulator 314 may convert the supply voltage from a direct current (DC) power supply to one or more constant voltages used by the components of the self-calibrating current measurement circuit 320, and one or more of the components may have voltage level requirements different from the voltage level requirements supplied by the DC power supply. In some embodiments, the power supply voltage regulator 314 can include a DC-DC converter or a low-dropout regulator (LDO).

[0040] Referring now to FIG. 4, this is an exemplary flowchart illustrating an exemplary method for evaluating current sensor performance according to some exemplary embodiments of the present disclosure. Note that each block of the flowchart, and combinations of blocks in the flowchart, can be implemented by various means such as hardware, firmware, circuitry, and / or other devices associated with the execution of software including one or more computer program instructions. For example, one or more of the steps / operations described in FIG. 4 may be embodied by computer program instructions stored by a non-transitory memory of a device adopting an embodiment of the present disclosure and executed by a processor component in the device (such as, but not limited to, MCU 310). For example, these computer program instructions may direct the processor component to function in a specific manner such that the instructions stored in the computer-readable storage memory create a product and its execution implements the functions specified in the flowchart blocks.

[0041] In FIG. 4, the exemplary method 400 can be executed by a computing device associated with a self-calibrating current measurement device (such as, at least as illustrated and described in relation to FIG. 3). In step 402, a first current sensor signal and a second current sensor signal are received. The first current sensor signal can include a digitized analog output voltage signal generated by a first current sensor (such as, low-range current sensor 302). The second current sensor signal can include a digitized analog output voltage signal generated by a second current sensor (such as, high-range current sensor 304). The analog output voltage signals generated by the first current sensor and the second current sensor can be based on, for example, a measurement of magnetic flux from a current-carrying conductor that represents (or is proportional to) the current amplitude of the current-carrying conductor. Thus, the first current signal and the second current signal each include a current amplitude reading measured by the first current sensor and the second current sensor, respectively.

[0042] In some embodiments, following step 402, the exemplary method proceeds to step 404 where a difference between the first current sensor signal and the second current sensor signal is determined in relation to the current reading. This difference can be used to determine current sensor drift. For example, the first current sensor signal may be used as a base reference to be compared with the second current sensor signal.

[0043] FIG. 5 presents an exemplary graph of linearity associated with a first current sensor signal and a second current sensor signal, according to various embodiments described herein. As illustrated in FIG. 5, the sensor output of the first current sensor 502 varies to various degrees with respect to the sensor output of the second current sensor 504 over the range of current measurements. The difference in sensor outputs can be due to a difference in measurement accuracy or precision between the first current sensor 502 and the second current sensor 504. Further, the difference in sensor outputs can result from linearity drift of at least one of the first current sensor 502 or the second current sensor 504. According to the exemplary embodiment, the first current sensor 502 may include a calibrated current sensor (e.g., a closed-loop current sensor such as the low-range current sensor 302 or a fluxgate current sensor), and the second current sensor 504 may include a measured current sensor (e.g., an open-loop current sensor such as the high-range current sensor 304). Thus, the sensor output of the first current sensor 502 can be used as a baseline reference for determining when to compensate for linearity drift of the sensor output from the second current sensor 504. The difference in sensor outputs for the current reading 506 can be determined and compared with a recalibration threshold.

[0044] Referring back to FIG. 4, in some embodiments, following step 404, the exemplary method proceeds to step 406, where the difference is compared to a recalibration threshold. The recalibration threshold may include a value representing the maximum allowable tolerance between the first current sensor signal and the second current sensor signal for a given current reading value without the need for recalibration. The recalibration threshold may include either a constant threshold or a plurality of variable thresholds across a range of current reading values. Thus, comparing the difference may include comparing the difference to a recalibration threshold associated with the current reading value.

[0045] FIGS. 6A and 6B present exemplary recalibration thresholds according to various embodiments described herein. An exemplary recalibration threshold including a constant threshold upper limit 602A and a constant threshold lower limit 604A across a range of current reading values is illustrated in FIG. 6A. Another exemplary recalibration threshold including an increasing threshold upper limit 602B (proportional to the absolute magnitude of the current reading value) and a decreasing threshold lower limit 604B (proportional to the absolute magnitude of the current reading value) is illustrated in FIG. 6B.

[0046] Referring back to FIG. 4, in some embodiments, following step 406, if the difference is greater than the recalibration threshold, the exemplary method proceeds to step 408, where recalibration of the current sensor is performed. Recalibration of the current sensor may include generating calibration data based on the difference and applying the calibration data to the measured current sensor. In an exemplary embodiment, the recalibration is performed on a sensor associated with the second current sensor signal (e.g., the high range current sensor 304). Recalibration of the current sensor is described in further detail with reference to the description of FIG. 7.

[0047] In some embodiments, following step 408, the exemplary method proceeds to step 410, where an output reading value is generated based on (i) the first current sensor signal or (ii) the second current sensor signal to which the calibration data has been applied.

[0048] In some embodiments, following step 406, if the difference is not greater than the recalibration threshold, the exemplary method proceeds directly to step 410 and an output reading value is generated based on the first current sensor signal or the second current sensor signal without applying the calibration data.

[0049] Referring now to FIG. 7, this is an exemplary flowchart illustrating an exemplary method for performing current sensor self-calibration according to some exemplary embodiments of the present disclosure. It should be noted that each block of the flowchart, and combinations of blocks in the flowchart, can be implemented by various means such as hardware, firmware, circuitry, and / or other devices associated with the execution of software including one or more computer program instructions. For example, one or more of the steps / operations described in FIG. 7 may be embodied by computer program instructions that are stored by a non-transitory memory of an apparatus adopting an embodiment of the present disclosure and may be executed by a processor component in the apparatus (such as, but not limited to, MCU 310). For example, these computer program instructions may direct the processor component to function in a particular manner such that the instructions stored in the computer-readable storage memory create a product and its execution implements the functions specified in the flowchart blocks.

[0050] In FIG. 7, an exemplary method 700 can be executed by a computing device associated with a self - calibrating current measurement device (e.g., as illustrated and described above in relation to at least FIG. 3). In step 702, first channel data and second channel data are received. The first channel data can include a sampling (e.g., over a sampling period) of a digital input signal from a channel associated with a first current sensor (e.g., low - range current sensor 302). The second channel data can include a sampling (e.g., over the same sampling period as the sampling associated with the first channel data) of a digital input signal from a channel associated with a second current sensor (e.g., high - range current sensor 304). The first channel data and the second channel data can each represent a current (e.g., a voltage based on magnetic flux) measured by the first current sensor and the second current sensor, respectively. In some embodiments, the first channel data and the second current sensor each include a digital voltage signal associated with a current amplitude reading measured by the first current sensor and the second current sensor, respectively. In some embodiments, the low - range current sensor can be associated with the first channel data and the high - range current sensor can be associated with the second channel data.

[0051] In some embodiments, following step 702, the exemplary method proceeds to step 704 where a determination is made as to whether the first channel data and the second channel data are associated with a measured value of a current within a low range. For example, the low range can represent the measurement range of the low - range current sensor. That is, step 704 determines that the measured current is a value measurable by the low - range current sensor (e.g., low - range current sensor 304) such that a comparison between the first channel data and the second channel data can be accurately made to perform calibration for the high - range current sensor (e.g., high - range current sensor 302).

[0052] In some embodiments, following step 704, if the measured current value is within the low range, the exemplary method proceeds to step 706, where the difference between the first channel data and the second channel data is determined and compared to a recalibration threshold. The recalibration threshold may include a value representing the maximum allowable difference between the first channel data and the second channel data without the need for recalibration. According to various embodiments of the present disclosure, the recalibration threshold may include a fixed threshold for all current values, or a variable value across different current reading values, as described above.

[0053] In some embodiments, following step 706, if the difference between the first channel data and the second channel data is greater than the recalibration threshold, the exemplary method proceeds to step 708, where new calibration data is generated and applied to the second channel data. The new calibration data may include a conversion function or mapping applied to the second channel data based on the first channel data. For example, by applying the calibration data to the second channel data, a linear transformation or segmented mapping related to the first channel data or the difference may be performed on the second channel data. In this way, the current measurement ability of the first channel data may be more accurate and reliable than the second channel data, enabling the first channel data to be used as a basis for correcting the second channel data.

[0054] According to various embodiments of the present disclosure, new calibration data can be used to skew the second channel data based on the difference between the first channel data and the second channel data. FIG. 8A illustrates exemplary linearity associated with the first channel data and the second channel data. As shown, the first channel data 802A and the second channel data 804A exhibit different linearity characteristics. However, by applying the new calibration data to the second channel data 804A, calibrated second channel data 804B that aligns with the first channel data 802A can be generated, as illustrated in FIG. 8B. Each time new calibration data is generated, the new calibration data can be assigned as current calibration data, and calibration data generated prior to the new calibration data (e.g., previously assigned as current calibration data or original calibration data) can be assigned as previous calibration data.

[0055] Referring back to FIG. 7, in some embodiments, following step 708, the exemplary method proceeds to step 710, and a current reading is generated based on the first channel data or the second channel data to which the new calibration data has been applied.

[0056] In some embodiments, following step 706, if the difference between the first channel data and the second channel data is not greater than the recalibration threshold, the exemplary method proceeds to step 710, and a current reading is generated based on the first channel data or the second channel data without applying calibration data.

[0057] In some embodiments, following step 710, the exemplary method proceeds to step 702, and another set of first channel data and second channel data is received.

[0058] In some embodiments, following step 704, if the measured current value is not within the low range, the exemplary method proceeds to step 712, and a determination is made as to whether new calibration data has been generated.

[0059] In some embodiments, following step 712, if new calibration data is generated, the exemplary method proceeds to step 714 where current calibration data is retrieved and applied. Otherwise, in some embodiments, following step 712, if no new calibration data is generated, the exemplary method proceeds to step 716 where previous calibration data is retrieved and applied. For example, the retrieved current calibration data or previous calibration data may be applied to second channel data (associated with a second current sensor such as high range current sensor 304). Current calibration data may refer to new calibration data, and previous calibration data may refer to calibration data generated prior to the new calibration data.

[0060] In some embodiments, following step 714 or 716, the exemplary method proceeds to step 718 where a current reading is generated based on the application of the second channel data and the retrieved calibration data (either the current calibration data from step 714 or the previous calibration data from step 716). That is, the retrieved calibration data may be applied to the second channel data to generate a current reading.

[0061] In some embodiments, following step 718, the exemplary method proceeds to step 702 where another set of first channel data and second channel data is received.

[0062] It is to be understood that the present disclosure is not limited to the particular embodiments disclosed, and modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims

1. A self - calibrating current measurement device, comprising: A low - range current sensor configured to generate a first voltage signal, the low - range current sensor including a closed - loop current sensor or a flux - gate current sensor; A high - range current sensor configured to generate a second voltage signal, the high - range current sensor including an open - loop current sensor; A self - calibrating current measurement circuit; wherein the self - calibrating current measurement circuit: Receives the first voltage signal and the second voltage signal; Converts the first voltage signal and the second voltage signal into a respective first digital signal and second digital signal; Compares the first digital signal with the second digital signal; Based on the comparison, determines that the difference between the first digital signal and the second digital signal exceeds a recalibration threshold; Generates calibration data based on the determination, where the calibration data converts the second voltage signal to match the first voltage signal; A self - calibrating current measurement device configured to generate a digital output signal representing a current reading value based on the application of the calibration data to the second digital signal.

2. A method for evaluating current sensor performance, the method comprising: Receiving, by a computing device, a first current sensor signal and a second current sensor signal; Determining, by the computing device, a difference between the first current sensor signal and the second current sensor signal in relation to a current reading value; Comparing, by the computing device, the difference with a recalibration threshold; Recalibrating, by the computing device, the second current sensor signal to match the first current sensor signal based on a determination that the difference is greater than the recalibration threshold; wherein The first current sensor signal is a signal generated by a closed - loop current sensor or a flux - gate current sensor, and the second current sensor signal is a signal generated by an open - loop current sensor.

3. A method for performing current sensor self - calibration, the method comprising: Receiving, by a computing device, first channel data and second channel data; The computing device compares the difference between the first channel data and the second channel data with a recalibration threshold value; The computing device generates new calibration data based on a determination that the difference is greater than the recalibration threshold value, where the new calibration data converts the second channel data to be consistent with the first channel data; The computing device applies the new calibration data to the second channel data; The computing device generates a current reading value based on the second channel data and the application of the new calibration data, and The first channel data represents a current measured by a closed-loop current sensor or a fluxgate current sensor, and the second channel data represents a current measured by an open-loop current sensor.

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