Method of self-calibration current sensor

A self-calibrating current measuring apparatus comprising a low-range current sensor configured to generate first voltage signals, a high-range current sensor configured to generate second voltage signals, and a self-calibration current measuring circuit configured to: receive the first voltage signals and the second voltage signals, convert the first voltage signals and the second voltage signals into respective first digital signals and second digital signals, compare the first digital signals with the second digital signals, determine a difference between the first digital signals and the second digital signals exceed a recalibration threshold based on the comparison, generate calibration data based on the determination, and generate a digital output signal representative of a current reading based on an application of the calibration data to the second digital signals.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority pursuant to 35 U.S.C. 119(a) to Chinese Application No. 202310495339.2, filed May 5, 2023, which application is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

Example embodiments of the present disclosure relate generally to current sensors, and in particular, current sensor apparatuses and methods for self-calibrating thereof.

BACKGROUND

Current sensors are employed in many industrial and automotive applications, such as battery management systems. In order to obtain detailed information about state of health and state of charge of battery, integrating accurate sensors into a battery monitoring system is critical. Current sensors may be employed to measure the current flowing into (when charging) and out of (when discharging) the battery. Applicant has identified many technical challenges and difficulties associated with conventional current sensors.

BRIEF SUMMARY

Various embodiments described herein relate to current sensor components, apparatuses, and methods for self-calibration.

In accordance with various embodiments of the present disclosure, a self-calibrating current measuring apparatus is provided. In some embodiments, the component comprises a low-range current sensor configured to generate first voltage signals, a high-range current sensor configured to generate second voltage signals, and a self-calibration current measuring circuit configured to receive the first voltage signals and the second voltage signals, convert the first voltage signals and the second voltage signals into respective first digital signals and second digital signals, compare the first digital signals with the second digital signals, determine a difference between the first digital signals and the second digital signals exceed a recalibration threshold based on the comparison, generate calibration data based on the determination, and generate a digital output signal representative of a current reading based on an application of the calibration data to the second digital signals.

In some embodiments, the self-calibration current measuring apparatus further comprises a communication module configured to receive the digital output and transmit the digital output to a battery management system. In some embodiments, the low-range current sensor comprises a closed-loop current sensor or a fluxgate current sensor. In some embodiments, the high-range current sensor comprises an open-loop current sensor.

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

In some embodiments, recalibrating the current sensor further comprises generating calibration data based on the difference, and applying the calibration data to a measurement current sensor. In some embodiments, the current sensor is associated with the second current sensor signal. In some embodiments, the first current sensor signal comprises a digitized analog output voltage signal generated by a first current sensor. In some embodiments, the first current sensor comprises a low-range current sensor. In some embodiments, the second current sensor signal comprises a digitized analog output voltage signal generated by a second current sensor. In some embodiments, the second current sensor comprises a high-range current sensor. In some embodiments, the recalibration threshold comprises a constant threshold value for a range of current reading values. In some embodiments, the recalibration threshold comprises a plurality of threshold values for a range of current reading values. In some embodiments, the method further comprises comparing the difference with a recalibration threshold value associated with the current reading value.

According to another embodiment, a method for performing current sensor self-calibration is provided. In some embodiments, the method comprises receiving, by a computing device, first channel data and second channel data. In some embodiments, the method further comprises comparing, by the computing device, a difference between the first channel data and the second channel data with a recalibration threshold. In some embodiments, the method further comprises 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 comprises applying, by the computing device, the new calibration data to the second channel data. In some embodiments, the method further comprises 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 comprising determining the first channel data and the second channel data are associated with a measurement of a current that is within a low range.

In some embodiments, the method further comprises determining the first channel data and the second channel data are not associated with a measurement of a current that is within a low range, determining the generation of the new calibration data, retrieving and applying current calibration data to the second channel data based on the determination of the generation of the new calibration data, and generating a current reading based on the second channel data and the application of the current calibration data. In some embodiments, the method further comprises determining the first channel data and the second channel data are not associated with a measurement of a current that is within a low range, retrieving and applying prior calibration data to the second channel data, and generating a current reading based on the second channel data and the application of the prior calibration data. In some embodiments, the method further comprises assigning the new calibration data as the current calibration data, and assigning calibration data generated prior to the new calibration data as prior calibration data. In some embodiments, the new calibration data comprises a linear transformation or a segmented mapping based on the first channel data or the difference.

The foregoing illustrative summary, as well as other exemplary objectives and/or advantages of the disclosure, and the manner in which the same are accomplished, are further explained in the following detailed description and its accompanying drawings.

DETAILED DESCRIPTION

As used herein, terms such as “front,” “rear,” “top,” etc., are used for explanatory purposes in the examples provided below to describe the relative position of certain components or portions of components. Furthermore, as would be evident to one of ordinary skill in the art in light of the present disclosure, the terms “substantially” and “approximately” indicate that the referenced element or associated description is accurate to within applicable engineering tolerances.

Along with electronics and semiconductor devices, current sensors are widely used to measure operation current in power systems, such as in electrical vehicle battery systems. However, there are many technical challenges and difficulties associated with current sensors. Current sensors may comprise devices used to measure the flow of current in an electric circuit. Current sensors may comprise either open or closed-loop circuits used to measure current flowing through a conductor. Open-loop current sensors offer various advantages, such as low cost, low power consumption, and simple construction.

Referring now toFIG.1, a system architecture of an open-loop current sensor100is provided, which may be used in accordance with various embodiments of the present disclosure. Open-loop current sensor100may be used for detection of a current through indirect sensing. As depicted inFIG.1, the open-loop current sensor100comprises a magnetic core104. The magnetic core104may comprise ferromagnetic materials, such as nanocrystalline and ferronickel materials.

The magnetic core104may comprise a ring-shaped object and an aperture comprising a void within an inner circumference of the magnetic core104. The aperture may be configured for detection of a current through indirect sensing. For example, a conductor120carrying an electrical current may be placed through the aperture formed by magnetic core104of open-loop current sensor100. The conductor120may comprise a busbar comprising a metallic bar or strip used to carry or transmit an electrical current.

Magnetic core104further comprises an air gap in which a magnetic transducer106, such as a Hall-effect sensor is placed. The magnetic transducer106may generate an output voltage in response to magnetic flux caused by a current in the conductor120within the aperture formed by magnetic core104. Electrical current carried by conductor102may produce a magnetic flux capable of inducing electromotive force (EMF), measured in voltage, according to Faraday's law of induction. The EMF may induce a current flow on the magnetic core104. As such, the magnetic transducer106may output a Hall voltage proportionate to the magnetic core's current flow. Amplifier108may amplify voltages from magnetic transducer106to generate output voltage, Vout112. Vout112may be taken directly from amplifier108to obtain voltage signals representative of current measurement.

Open-loop current sensors, such as the open-loop current sensor100depicted inFIG.1, comprises an approach for detecting current on a conductor (e.g., conductor120), with advantages, such as low cost, low power consumption and simple construction. However, the performance (e.g., linearity) of open-loop current sensor may be affected by magnetic hysteresis and environmental factors, such as humidity and temperature, causing zero drift and changes in magnetic transducer sensitivity. Accordingly, accuracy of open-loop current sensors may be difficult to achieve due to non-linearity caused by saturation effects and humidity/temperature.

FIG.2is a graph depicting example loss in performance of an open-loop current sensor exhibiting linearity drift. An open-loop current sensor with linearity drift prohibits obtainment of accurate measurements and may benefit from recalibration. However, another major drawback of open-loop current sensors is that recalibration may only be performed in a laboratory (e.g., by the manufacturer).

Other types of sensors, such as closed-loop current sensors may be used as an alternative to open-loop current sensors. For example, unlike an open-loop current sensor, a closed-loop current sensor is resistant to linearity drift in sensor sensitivity and offers higher measurement accuracy. A closed-loop current sensor may comprise components similar to an open-loop current sensor with the addition of a wire coil wrapped around the magnetic core. The wire coil may be driven by the detection voltage (e.g., Vout112) of the conductor to feed an opposing current into the wire coil to create a flux balance that balances out the flux generated by the conductor current. Balancing in this way may eliminate the effects of temperature/humidity and saturation and allows for more accurate measurements. Fluxgate current sensors are also similar in operation to a closed-loop current sensor but may instead employ a saturable inductor using a small thin magnetic core to sense an air gap field, rather than a Hall-effect sensor. However, the added complexity of either closed-loop current sensors or fluxgate current sensors leads to higher cost. Thus, closed-loop current sensors and fluxgate current sensors are typically more accurate but higher in cost than open-loop current sensors.

Various example embodiments of the present disclosure overcome such technical challenges and difficulties in current sensors, and provide various technical advancements and improvements. In particular, a multi-sensor current measuring apparatus and a self-calibration method are disclosed herewith. A multi-sensor current measuring apparatus may comprise a plurality of current sensors with complementary capabilities such that advantages provided by each current sensor are utilized by the coexistence of the plurality of current sensors within a single apparatus. In some embodiments, a multi-sensor current measuring apparatus may comprise a calibration current sensor and a measurement current sensor. Measurements obtained by the measurement current sensor may be primarily provided as measured current readings and measurements obtained by the calibration current sensor may be provided as measured current readings as well as serving as a measurement reference to the measurement current sensor for determining accuracy of the measurement current sensor and whether calibration of the measurement current sensor is needed.

FIG.3presents an example schematic of a self-calibrating current measuring apparatus according to various embodiments described herewith. The self-calibrating current measuring apparatus300comprises a low-range current sensor302and a high-range current sensor304. That is, the self-calibrating current measuring apparatus300may simultaneously employ a combination of current sensors (e.g., with complementary capabilities) within a single apparatus. To prevent cross interference, the low-range current sensor302and the high-range current sensor304may be configured such that at least one magnetic transducer/inductor of the low-range current sensor302or the high-range current sensor304is separated, covered, or otherwise shielded.

In some embodiments, the low-range current sensor302may comprise a closed-loop current sensor or a fluxgate current sensor, and the high-range current sensor304may comprise an open-loop current sensor. As previously described, an open-loop current sensor (e.g., high-range current sensor304) may be influenced by magnetic hysteresis and environmental factors, which affects measurement accuracy, while a closed-loop current sensor or a fluxgate current sensor (e.g., low-range current sensor302) may be resistant to such influences and may be capable of providing relatively more stable and reliable current measurements. According to various embodiments of the present disclosure, the self-calibrating current measuring apparatus300may selectively employ the low-range current sensor302and the high-range current sensor304for certain functionalities based on their device capabilities. For example, the high-range current sensor304may be used to generate current readings due to its greater measurement range over the low-range current sensor302, whereas the low-range current sensor302, being able to measure current with a higher degree of accuracy than the high-range current sensor304, may be used to provide reference measurements to calibrate current measurements of the high-range current sensor304.

The low-range current sensor302may comprise a current sensor capable of measuring a first range of current with a first amount of accuracy. The high-range current sensor304may comprise a current sensor capable of measuring a second range of current with a second amount of accuracy. According to various embodiments of the present disclosure, the first range of current may be less than the second range of current and the first amount of accuracy may be more than the second amount of accuracy. As such, the low-range current sensor302may be capable of (i) measuring a range of current values that is smaller than the measurement range of the high-range current sensor304, and (ii) measuring current with a higher degree of accuracy than the accuracy of the high-range current sensor304. Conversely, the high-range current sensor304may be capable of (i) measuring a range of current values that is larger than the measurement range of the low-range current sensor302, and (ii) measuring current with a lower degree of accuracy than the accuracy of the low-range current sensor302.

In some embodiments, low-range current sensor302and high-range current sensor304may be concurrently used to measure current, provided that current being measured is within a measuring range of both the low-range current sensor302and the high-range current sensor304. For example, low-range current sensor302may be capable of measuring current in a range of approximately 0-300 A while high-range current sensor304may be capable of measuring current in a range greater than (e.g., the upper limit, the lower limit, or both) the measurement range of the low-range current sensor302, for example, approximately 50-600 A. Thus, according to the given example, low-range current sensor302and high-range current sensor304may be concurrently used to measure current for current values within the range of approximately 50-300 A. In some other embodiments, low-range current sensor302may be capable of measuring current in a range of approximately −300A to300A, and the high-range current sensor304may be capable of measuring current in a range of approximately −1500A to1500A.

The low-range current sensor302and the high-range current sensor304may comprise a measuring passthrough, aperture, or area of detection configured to receive, conduct, or sense a magnetic flux generated by a current carrying conductor (e.g., wire, cable, or bus). The induced magnetic flux may be detected by respective magnetic transducers of the low-range current sensor302and the high-range current sensor304. The low-range current sensor302and the high-range current sensor304may generate analog output voltage signals based on the induced magnetic flux (e.g., proportional to the induced magnetic flux). The analog output voltage signals generated by low-range current sensor302and high-range current sensor304may be transmitted to a self-calibration current measuring circuit320.

According to various embodiments of the present disclosure, self-calibration current measuring circuit320may use the analog output voltage signals from low-range current sensor302and high-range current sensor304to generate current readings and perform self-calibration. Current readings may be generated based on voltage signals from at least one of the low-range current sensor302or the high-range current sensor304. In some embodiments, current readings may be based on voltage signals from the high-range current sensor304, and voltage signals from the low-range current sensor302may be used as a reference for calibrating the high-range current sensor304. For example, voltage signals from the low-range current sensor302may be compared with voltage signals from the high-range current sensor304to detect linearity drift of the high-range current sensor304.

Self-calibration current measuring circuit320comprises regulator circuit306, analog-to-digital converter (ADC)308, microcontroller unit (MCU)310, communication module312, and power source voltage regulator314. Low-range current sensor302and high-range current sensor304are coupled to regulator circuit306via channels. In some embodiments, a channel, as disclosed herewith, describes a physical transmission medium, such as a wire, cable, or link, and an interface dedicated to transferring signals from a specific source. Analog output voltage signals (e.g., Vout) from low-range current sensor302and high-range current sensor304may be transmitted to the regulator circuit306using respective channels. For example, a first channel may be designated to transmit analog output voltage signals from the low-range current sensor302to the regulator circuit306and a second channel may be designated to transmit analog output voltage signals from the high-range current sensor304to the regulator circuit306. As such, the source of signals received by regulator circuit306are identifiable by the channel in which the signals are received.

Regulator circuit306may comprise electronic or circuit components configured to regulate analog voltages received from low-range current sensor302and high-range current sensor304to prevent overvoltage (e.g., voltages beyond the limits of self-calibration current measuring circuit320). For example, the regulator circuit306may protect the self-calibration current measuring circuit320from overvoltage by supplying a regulated voltage when a voltage received from either low-range current sensor302, or high-range current sensor304exceeds a threshold voltage. Regulator circuit306may pass through regulated analog voltages associated with the low-range current sensor302and high-range current sensor304to analog-to-digital converter (ADC)308.

ADC308may comprise one or more circuit or electronic components configured to convert an analog voltage to a digital number representing the magnitude of the analog voltage. For example, ADC308may convert a continuous-time and continuous-amplitude analog signal to a discrete-time and discrete-amplitude digital signal. According to various embodiments of the present disclosure, the self-calibration current measuring circuit320may use the ADC308to convert the regulated analog output voltage signals associated with the low-range current sensor302and high-range current sensor304into respective digital signals for processing by microcontroller unit (MCU)310. For example, MCU310may process a first digital input signal representative of the analog output voltage signal associated with the low-range current sensor302and a second digital input signal representative of the analog output voltage signal associated with the high-range current sensor304to generate a digital output signal comprising a current reading. The current reading may be an estimated current of a current carrying conductor which may be calculated based on a conversion of digital input signals associated with at least one of the low-range current sensor302or the high-range current sensor304. In some embodiments, the digital output signal may be generated using only digital input signals of the high-range current sensor304, for example, if a current being measured is outside the measuring range of the low-range current sensor302.

The MCU310may further compare the first digital input signal representative of analog output voltage signals associated with the low-range current sensor302with the second digital input signal representative of analog output voltage signals associated with the high-range current sensor304to determine whether calibration of the high-range current sensor304is needed. For example, the MCU310may monitor differences between the first digital input signal representative of the analog output voltage signal associated with the low-range current sensor302and the second digital input signal representative of the analog output voltage signal associated with the high-range current sensor304and determine when a monitored difference exceeds a recalibration threshold. In some embodiments, if the differences do not exceed the recalibration threshold, a digital output signal comprising a current reading is generated based on at least one of the first digital input signal or the second digital input signal. In some additional embodiments, if the differences exceed the recalibration threshold, a self-recalibration method is performed to generate calibration data, which is described in further detail with respect to the description ofFIG.7. Calibration data, as disclosed herewith, may describe a transformation function or mapping used to align data from a measurement current sensor with data from a calibration current sensor. In some embodiments, the calibration data may be applied to, for example, the second digital input signal, for generating a digital output signal that reflects a measurement by the high-range current sensor304calibrated based on the first digital input signal associated with the low-range current sensor302.

MCU310may comprise a processing element 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 MCU310may be embodied as one or more other processing devices or circuitry. The term circuitry may refer to an entirely hardware embodiment or a combination of hardware and computer program products. Thus, the MCU310may be embodied as integrated circuits, application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), programmable logic arrays (PLAs), hardware accelerators, other circuitry, and/or the like.

As will therefore be understood, the MCU310may be configured for a particular use or configured to execute instructions stored in volatile or non-volatile media or otherwise accessible to the MCU310. As such, whether configured by hardware or computer program products, or by a combination thereof, the MCU310may be capable of performing steps or operations according to embodiments of the present disclosure when configured accordingly.

Digital output signals generated by the MCU310may be received by communication module312for communication of the digital output signals to various computing entities, such as by communicating data comprising the digital output signals, e.g., representative of a measured current of a current carrying conductor, that can be transmitted, received, operated on, processed, displayed, stored, and/or the like. In some embodiments, the communication module312may 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, communication module312may transmit and receive data, in accordance with air interface standards of applicable wireless systems. In this regard, the self-calibrating current measuring apparatus300may be capable of operating with one or more air interface standards, communication protocols, modulation types, and access types. More particularly, the self-calibrating current measuring apparatus300may operate in accordance with any of a number of wireless communication standards and protocols, such as those described above with regard to the predictive data analysis computing entity106. In some embodiments, the self-calibrating current measuring apparatus300may operate in accordance with multiple wireless communication standards and protocols, such as UMTS, CDMA2000, 1×RTT, 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 measuring apparatus300may operate in accordance with 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.

Power source voltage regulator314may comprise one or more circuit or electronic components configured to provide relatively steady supply voltage(s) to components of self-calibration current measuring circuit320(regulator circuit306, ADC308, MCU310, and communication module312). For example, the power source voltage regulator314may convert a supply voltage from a direct current (DC) power supply to one or more constant voltages used by components of the self-calibration current measuring circuit320where one or more of the components may have voltage level requirements different from that supplied by the DC power supply. In some embodiments, the power source voltage regulator314may comprise a DC-to-DC converter or a low-dropout regulator (LDO).

Referring now toFIG.4, an example flow diagram illustrating an exemplary method for evaluating current sensor performance in accordance with some example embodiments of the present disclosure. It is noted that each block of a flowchart, and combinations of blocks in the flowchart, may be implemented by various means such as hardware, firmware, circuitry, and/or other devices associated with execution of software including one or more computer program instructions. For example, one or more of the steps/operations described inFIG.4may be embodied by computer program instructions, which may be stored by a non-transitory memory of an apparatus employing an embodiment of the present disclosure and executed by a processor component in an apparatus (such as, but not limited to, MCU310). 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 produce an article of manufacture, the execution of which implements the function specified in the flowchart block(s).

InFIG.4, the example method400may be executed by a computing device associated with a self-calibrating current measuring apparatus (for example, as illustrated and described above in connection with at leastFIG.3). At step402, a first current sensor signal and a second current sensor signal are received. The first current sensor signal may comprise a digitized analog output voltage signal generated by a first current sensor (e.g., low-range current sensor302). The second current sensor signal may comprise a digitized analog output voltage signal generated by a second current sensor (e.g., high-range current sensor304). The analog output voltage signals generated by the first current sensor and the second current sensor may be based on measurements of magnetic flux, e.g., from a current carrying conductor, representative of (or proportional to) current amplitude of the current carrying conduct. As such, the first current signal and the second current signal comprise current amplitude readings measured by the first current sensor and the second current sensor, respectively.

In some embodiments, subsequent to step402, the example method proceeds to step404, where a difference between the first current sensor signal and the second current sensor signal is determined in association with a current reading value. The difference may be used to determine current sensor drift. For example, the first current sensor signal may be used as a base reference that is compared with the second current sensor signal.

FIG.5presents an example graph of linearity associated with a first current sensor signal and a second current sensor signal in accordance with various embodiments described herewith. As depicted inFIG.5, sensor outputs of first current sensor502differ in various degrees with respect to sensor outputs of second current sensor504over a range of current measurements. The difference in sensor outputs may be attributed to a difference in measurement accuracy or precision between first current sensor502and second current sensor504. Moreover, the difference in sensor outputs may result from linearity drift of at least one of the first current sensor502or the second current sensor504. According to the illustrated example, the first current sensor502may comprise a calibration current sensor (e.g., a closed-loop current sensor or a fluxgate current sensor, such as low-range current sensor302) and the second current sensor504may comprise a measurement current sensor (e.g., an open-loop current sensor, such as high-range current sensor304). As such, sensor output of the first current sensor502may be used as a baseline reference to determine when to compensate for linearity drift of sensor output from the second current sensor504. A difference in the sensor outputs for current reading value506may be determined and compared with a recalibration threshold.

Referring back toFIG.4, in some embodiments, subsequent to step404, the example method proceeds to step406, where the difference is compared with a recalibration threshold. The recalibration threshold may comprise a value representative of a maximum allowable difference between the first current sensor signal and the second current sensor signal for a given current reading value without having to perform a recalibration. The recalibration threshold may comprise either a constant threshold value or a plurality of variable threshold values across a range of current reading values. As such, comparing the difference may comprise comparing the difference with a recalibration threshold value associated with the current reading value.

FIG.6AandFIG.6Bpresent example recalibration thresholds in accordance with various embodiments described herewith. An example recalibration threshold comprising a constant upper threshold limit602A and a constant lower threshold limit604A across a range of current reading values is depicted inFIG.6A. Another example recalibration threshold comprising an increasing upper threshold limit602B (in proportion to absolute magnitude current reading values) and decreasing lower threshold limit604B (in proportion to absolute magnitude current reading values) is depicted inFIG.6B.

Referring back toFIG.4, in some embodiments, subsequent to step406, if the difference is greater than the recalibration threshold, the example method proceeds to step408, where a recalibration of a current sensor is performed. Recalibration of a current sensor may comprise generating calibration data based on the difference and applying the calibration data to a measurement current sensor. In an example embodiment, the recalibration is performed on a sensor associated with the second current sensor signal (e.g., a high-range current sensor304). Recalibration of a current sensor is described in further detail with reference to the description ofFIG.7.

In some embodiments, subsequent to step408, the example method proceeds to step410, where an output reading is generated based on (i) the first current sensor signal or (ii) the second current sensor signal applied with calibration data.

In some embodiments, subsequent to step406, if the difference is not greater than the recalibration threshold, the example method directly proceeds to step410, where an output reading is generated based on the first current sensor signal or the second current sensor signal, without the application of calibration data.

Referring now toFIG.7, an example flow diagram illustrating an exemplary method for performing current sensor self-calibration in accordance with some example embodiments of the present disclosure. It is noted that each block of a flowchart, and combinations of blocks in the flowchart, may be implemented by various means such as hardware, firmware, circuitry, and/or other devices associated with execution of software including one or more computer program instructions. For example, one or more of the steps/operations described inFIG.7may be embodied by computer program instructions, which may be stored by a non-transitory memory of an apparatus employing an embodiment of the present disclosure and executed by a processor component in an apparatus (such as, but not limited to, MCU310). 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 produce an article of manufacture, the execution of which implements the function specified in the flowchart block(s).

InFIG.7, the example method700may be executed by a computing device associated with a self-calibrating current measuring apparatus (for example, as illustrated and described above in connection with at leastFIG.3). At step702, first channel data and second channel data are received. The first channel data may comprise a sampling of digital input signals (e.g., over a sampling period) from a channel associated with a first current sensor (e.g., low-range current sensor302). The second channel data may comprise a sampling (e.g., over the same sampling period as the sampling associated with the first channel data) of digital input signals from a channel associated with a second current sensor (e.g., high-range current sensor304). The first channel data and the second channel data may be representative of current (e.g., 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 comprise digital voltage signals associated with current amplitude readings measured by the first current sensor and the second current sensor, respectively. In some embodiments, a low-range current sensor may be associated with the first channel data and a high-range current sensor may be associated with the second channel data.

In some embodiments, subsequent to step702, the example method proceeds to step704, where a determination is made whether the first channel data and the second channel data are associated with a measurement of a current that is within a low range. For example, the low range may be representative of a measuring range of a low-range current sensor. That is, step704determines that a current being measured is a value that is measurable by a low-range current sensor (e.g., low-range current sensor302) such that a comparison between the first channel data and the second channel data may be accurately made to perform a calibration on a high-range current sensor (e.g., high-range current sensor304).

In some embodiments, subsequent to step704, if the current measurement is within the low range, the example method proceeds to step706, where a difference between the first channel data and the second channel data is determined and compared with a recalibration threshold. The recalibration threshold may comprise a value representative of a maximum allowable difference between the first channel data and the second channel data without having to perform a recalibration. According to various embodiments of the present disclosure, the recalibration threshold may comprise a constant threshold value for all current values or a variable value across different current reading values, as previously described.

In some embodiments, subsequent to step706, if the difference between the first channel data and the second channel data is greater than the recalibration threshold, the example method proceeds to step708, where new calibration data is generated and applied to the second channel data. The new calibration data may comprise a transformation function or mapping that is applied to the second channel data based on the first channel data. For example, a linear transformation or segmented mapping, with respect to the first channel data or the difference, may be performed on to the second channel data by applying calibration data to the second channel data. As such, current measuring capability of the first channel data may be more accurate and reliable than the second channel data allowing for the first channel data to be used as a basis for correction of the second channel data.

According to various embodiments of the present disclosure, the new calibration data may be used to skew the second channel data based on a difference between the first channel data and the second channel data.FIG.8Adepicts example linearity associated with first channel data and second channel data. As depicted, first channel data802A and second channel data804A exhibit different linearity characteristics. However, by applying new calibration data to the second channel data804A, calibrated second channel data804B may be generated that aligns with the first channel data802A, as depicted inFIG.8B. For every instance new calibration data is generated, the new calibration data may 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) may be assigned as prior calibration data.

Referring back toFIG.7, in some embodiments, subsequent to step708, the example method proceeds to step710, where a current reading is generated based on the first channel data or the second channel data applied with the new calibration data.

In some embodiments, subsequent to step706if the difference between the first channel data and the second channel data is not greater than the recalibration threshold, the example method proceeds to step710, where a current reading is generated based on the first channel data or the second channel data, without the application of calibration data.

In some embodiments, subsequent to step710, the example method proceeds to step702, where another set of first channel data and second channel data is received.

In some embodiments, subsequent to step704, if the current measurement is not within the low range, the example method proceeds to step712, where a determination is made whether new calibration data was generated.

In some embodiments, subsequent to step712, if new calibration data was generated, the example method proceeds to step714, where current calibration data is retrieved and applied. Otherwise, in some embodiments, subsequent to step712, if new calibration data was not generated, the example method proceeds to step716, where prior calibration data is retrieved and applied. For example, the retrieved current calibration data or prior calibration data may be applied to the second channel data (associated with the second current sensor, such as high-range current sensor304). Current calibration data may refer to the new calibration data and prior calibration data may refer to calibration data generated prior to the new calibration data.

In some embodiments, subsequent to steps714or716, the example method proceeds to step718, where a current reading is generated based on the second channel data and the application of the retrieved calibration data (either current calibration data from step714, or prior calibration data from step716). That is, the retrieved calibration data may be applied to the second channel data to generate the current reading.

In some embodiments, subsequent to step718, the example method proceeds to step702, where another set of first channel data and second channel data is received.