An adaptive calibration method and device of a circuit breaker and the circuit breaker

Abstract

The application relates to the technical field of circuit breakers, in particular to a self-adaptive calibration method and device of a circuit breaker and the circuit breaker. The method comprises the following steps: synchronously sampling a main loop current and a stable voltage of a microcontroller unit by using an analog-to-digital converter, so as to obtain a main loop current sampling value and a stable voltage sampling value; judging whether to start a multi-stage dynamic calibration algorithm according to the stable voltage sampling value and a reference voltage; if the multi-stage dynamic calibration algorithm is started, obtaining a fluctuation level of a power supply voltage of the circuit breaker, and performing corresponding calibration processing based on a calibration value, the main loop current sampling value and the fluctuation level, so as to obtain a main loop current calibration value as a real sampling value collected by the analog-to-digital converter from the main loop. The application can effectively solve the problems that the existing circuit breaker has low safety and high cost due to unstable connection of the power supply voltage.

Description

Technical Field

[0001] This application relates to the field of circuit breaker technology, and in particular to an adaptive calibration method, apparatus and circuit breaker for a circuit breaker. Background Technology

[0002] Electronic molded case circuit breakers (MCCBs) are powered by current transformers drawing power from the main circuit. They operate well when the main circuit current is high, providing a stable and reliable power supply to the circuit. However, when the main circuit current is low (<20%In), the output power of the current transformer decreases significantly and becomes unstable. After rectification, filtering, and voltage regulation, the analog power supply voltage provided to the microcontroller unit (MCU) is... A This will produce a significant voltage drop and fluctuation. (Analog power supply voltage) A Voltage drops and fluctuations can increase the error in the circuit sampling current, and may even cause false tripping, resulting in a significant reduction in the reliability of the circuit breaker.

[0003] For example, a current sensor collects the current in the main circuit to obtain the circuit sampling current, if the simulated power supply voltage... A When voltage drop and fluctuations occur, the error in the circuit's sampled current increases. The current transformer converts the sampled current into a sampled voltage. The sampled voltage is amplified and filtered by the signal conditioning circuit to obtain an analog voltage. The analog-to-digital converter (ADC) converts the analog voltage into a digital voltage and transmits it to the MCU. The MCU analyzes the digital voltage to obtain a digital current value. At this point, because the error in the circuit's sampled current has increased, and the error in the digital current value is also large, the MCU determines that the protection strategy is not met based on the large error in the digital current value, and triggers a trip signal, driving the electromagnetic trip unit to operate.

[0004] Some existing calibration schemes have limitations:

[0005] Some designs disregard this error: In some circuit breaker products, designers may completely ignore this error, resulting in serious safety hazards for the circuit breaker products.

[0006] Others add an external, high-precision reference voltage source as the voltage reference source for ADC sampling. Summary of the Invention

[0007] In view of this, embodiments of this application provide an adaptive calibration method, apparatus and circuit breaker for a circuit breaker, which can effectively solve the problems of low safety and high cost of existing circuit breakers due to unstable power supply voltage.

[0008] In a first aspect, embodiments of this application provide an adaptive calibration method for a circuit breaker, the circuit breaker including a microcontroller unit and an analog-to-digital converter, the method comprising:

[0009] The analog-to-digital converter is used to synchronously sample the main circuit current and the stable voltage of the microcontroller unit to obtain the corresponding sampled values ​​of the main circuit current and the stable voltage.

[0010] Whether to activate the multi-level dynamic calibration algorithm is determined based on the stable voltage sample value and the acquired reference voltage.

[0011] If the multi-level dynamic calibration algorithm is activated, the fluctuation level of the power supply voltage of the circuit breaker is obtained. Based on the calibration value, the sampled value of the main circuit current, and the fluctuation level, corresponding calibration processing is performed to obtain the calibration value of the main circuit current, which is used as the real sampled value collected by the analog-to-digital converter from the main circuit.

[0012] In some embodiments, the calibration process based on the calibration value, the main circuit current sample value, and the fluctuation level to obtain the main circuit current calibration value includes:

[0013] If the fluctuation level is slight fluctuation, then:

[0014] The calibration value is determined based on the voltage ratio between the reference voltage and the stable voltage sample value; the calibration value is then obtained by performing mathematical calculations on the calibration value and the main circuit current sample value.

[0015] If the volatility level is moderate volatility, then:

[0016] The calibration value is calculated using a combination of table lookup and piecewise linear interpolation based on the voltage ratio between the reference voltage and the stable voltage sample value. A calibration process involving mathematical operations is then performed on the calibration value and the main circuit current sample value to obtain the main circuit current calibration value.

[0017] If the fluctuation level is severe, then the multi-level dynamic calibration algorithm is turned off.

[0018] In some embodiments, the calculation of the calibration value using a combination of table lookup and piecewise linear interpolation includes:

[0019] The voltage ratio is matched and searched in a pre-stored calibration value table;

[0020] If a match search fails, the corresponding calibration deviation value is calculated using piecewise linear interpolation between two adjacent entries, and used as the calibration value.

[0021] In some embodiments, the method further includes:

[0022] When the main circuit current is detected to have entered a stable current state, the current reference voltage is adaptively updated based on the currently acquired stable voltage sample value and the adaptive learning rate.

[0023] In some embodiments, the step of adaptively updating the current reference voltage based on the currently acquired stable voltage sample value and the adaptive learning rate includes:

[0024] When the main circuit current is in a stable state, multiple stable voltage samples are collected, and the average voltage is calculated.

[0025] The updated reference voltage is obtained by performing a weighted average calculation based on the average voltage, the current reference voltage, and the weight coefficients determined based on the adaptive learning rate.

[0026] In some embodiments, the updated reference voltage is calculated using the following formula:

[0027] core_new =(1-LEARN_RATE)× core_CAL +LEARN_RATE× core_AVG

[0028] in, core_new This represents the updated reference voltage, and LEARN_RATE represents the adaptive learning rate. core_CAL This indicates the current reference voltage. core_AVG This represents the average voltage under steady-state conditions.

[0029] In some embodiments, the method further includes the following two items:

[0030] First: The stable voltage of the microcontroller unit is adopted from the core voltage of the microcontroller unit;

[0031] The method of synchronously sampling the main circuit current and the stable voltage of the microcontroller unit using the analog-to-digital converter includes:

[0032] The voltage of the voltage regulator inside the microcontroller unit is acquired using the analog-to-digital converter to obtain the core voltage sample value, which is then used as the stable voltage sample value.

[0033] The second item: The initial reference voltage is the core voltage that is pre-measured under external stable power supply and standard environmental conditions before the circuit breaker leaves the factory, and it is stored in the memory of the circuit breaker.

[0034] Third item:

[0035] The updated reference voltage is stored in the circuit breaker's memory based on a preset period;

[0036] Fourth item: Perform anomaly detection on the updated reference voltage, and update the current reference voltage if the anomaly detection passes.

[0037] In some embodiments, the fluctuation level of the power supply voltage of the circuit breaker is obtained by the following methods:

[0038] When a deviation between the stable voltage sample value and the reference voltage is detected, the fluctuation level of the power supply voltage of the circuit breaker is determined.

[0039] Secondly, embodiments of this application provide an adaptive calibration device for a circuit breaker, the circuit breaker including a microcontroller unit and an analog-to-digital converter, the device comprising:

[0040] The sampling module is used to synchronously sample the main circuit current and the stable voltage of the microcontroller unit using the analog-to-digital converter, and obtain the sampled values ​​of the main circuit current and the stable voltage accordingly.

[0041] The calibration startup management module is used to determine whether to start the multi-level dynamic calibration algorithm based on the stable voltage sample value and the acquired reference voltage.

[0042] The calibration module is used to obtain the fluctuation level of the power supply voltage of the circuit breaker if a multi-level dynamic calibration algorithm is activated, and to perform corresponding calibration processing based on the calibration value, the sampled value of the main circuit current and the fluctuation level to obtain the calibration value of the main circuit current, which is used as the real sampled value collected by the analog-to-digital converter from the main circuit.

[0043] Thirdly, embodiments of this application provide a circuit breaker, which includes a microcontroller unit, an analog-to-digital converter, and a memory. The memory stores a computer program, and the microcontroller unit is used to execute the computer program to implement an adaptive calibration method for a circuit breaker provided in the first aspect of this application.

[0044] The embodiments of this application have the following beneficial effects:

[0045] This application utilizes an analog-to-digital converter (ADC) to synchronously sample the main circuit current and the stable voltage of the microcontroller unit, obtaining corresponding sampled values ​​for the main circuit current and stable voltage. Based on the stable voltage sampled value and the acquired reference voltage, it determines whether to activate a multi-level dynamic calibration algorithm. If activated, the fluctuation level of the circuit breaker's power supply voltage is acquired. Based on the calibration value, the main circuit current sampled value, and the fluctuation level, corresponding calibration processing is performed to obtain the calibrated value of the main circuit current, which serves as the true sampled value collected by the ADC from the main circuit. This application improves the measurement accuracy of the main circuit current by calibrating the sampled main circuit current without adding any hardware. It effectively solves the problems of low safety and high cost in existing circuit breakers due to unstable power supply voltage. Attached Figure Description

[0046] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0047] Figure 1 A flowchart of an adaptive calibration method for a circuit breaker according to an embodiment of this application is shown;

[0048] Figure 2 A flowchart of a multi-level dynamic calibration process in the adaptive calibration method for a circuit breaker according to an embodiment of this application is shown;

[0049] Figure 3 A flowchart illustrating the updating of the reference voltage in the adaptive calibration method for a circuit breaker according to an embodiment of this application is shown.

[0050] Figure 4 A schematic diagram of an adaptive calibration device for a circuit breaker according to an embodiment of this application is shown.

[0051] Explanation of key component symbols:

[0052] 410 - Sampling module; 420 - Calibration start management module; 430 - Calibration module. Detailed Implementation

[0053] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0054] The components of the embodiments of this application described and illustrated in the accompanying drawings can be arranged and designed in a variety of different configurations. Therefore, the following detailed description of the embodiments of this application provided in the drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0055] In the following text, the terms "comprising," "having," and their cognates, which may be used in various embodiments of this application, are intended only to indicate a particular feature, number, step, operation, element, component, or combination thereof, and should not be construed as primarily excluding the presence of one or more other features, numbers, steps, operations, elements, components, or combinations thereof, or adding the possibility of one or more combinations thereof. Furthermore, the terms "first," "second," "third," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance.

[0056] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which the various embodiments of this application pertain. Terms (such as those defined in commonly used dictionaries) shall be interpreted as having the same meaning as in their contextual meaning in the relevant technical field and shall not be construed as having an idealized or overly formal meaning, unless clearly defined in the various embodiments of this application.

[0057] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0058] This application provides an adaptive calibration method, apparatus, and circuit breaker for correcting offset and gain errors in digital quantities sampled by an ADC, thereby reducing the impact of circuit sampling current errors on the MCU and improving safety.

[0059] This application provides a circuit breaker, exemplary of which includes a microcontroller unit (MCU), a current transformer, an analog-to-digital converter (ADC), etc.

[0060] A circuit breaker is connected between the power supply to the load and the load itself. It is used to connect or disconnect the main circuit to control whether the load is energized and to automatically disconnect the circuit in case of a fault to achieve protection.

[0061] The main circuit refers to the current path formed between the power supply, the circuit breaker, and the load. For example, the main circuit is the complete current path from the power supply output terminal → the circuit breaker input terminal → the circuit breaker output terminal → the load → back to the power supply.

[0062] The circuit breaker includes, but is not limited to, electronic circuit breakers. The operating power of the internal controller unit of the circuit breaker is obtained through current transformers integrated into the main circuit. In other words, the operating power of the microcontroller unit (MCU) is obtained from the main circuit through the current transformer.

[0063] The voltage on the main circuit is used as the power supply voltage (V) for the microcontroller unit. CC The voltage output from the current transformer in the main circuit is regulated and used as the power supply voltage (VCC) for the microcontroller unit.

[0064] Understandably, the method of this application is applicable to microcontroller units (MCUs) in electronic circuit breakers that rely on current transformers for power. For example, electronic molded case circuit breakers (MCCBs).

[0065] The adaptive calibration method for this circuit breaker will be explained below with reference to some specific embodiments.

[0066] Figure 1 A flowchart illustrating an adaptive calibration method for a circuit breaker according to an embodiment of this application is shown. Exemplarily, the adaptive calibration method for this circuit breaker includes the following steps:

[0067] S100, the analog-to-digital converter is used to synchronously sample the main circuit current and the stable voltage of the microcontroller unit to obtain the sampled values ​​of the main circuit current and the stable voltage.

[0068] The stable voltage is the voltage V supplied by the circuit breaker within the microcontroller unit. cc Voltage fluctuations. The stable voltage of a microcontroller unit includes, but is not limited to, the core voltage and the internal bandgap reference voltage (V). BG ), internal reference voltage channel (such as STM32's VREFINT), temperature sensor bias voltage (related to V), BG (Related), etc.

[0069] By way of example, in an embodiment of this application, the stable voltage of the microcontroller unit is the core voltage of the microcontroller unit.

[0070] In step S100, the step of synchronously sampling the main circuit current and the stable voltage of the microcontroller unit using the analog-to-digital converter includes:

[0071] The voltage of the voltage regulator inside the microcontroller unit (MCU) is acquired using the analog-to-digital converter (ADC) to obtain the core voltage sample value, which is then used as the stable voltage sample value. For example, this can be achieved through an ADC... The REFINT channel periodically samples the core voltage to obtain the core voltage sample value.

[0072] Core voltage refers to the stable DC voltage inside the microcontroller unit that supplies power to the processor core and key digital logic circuits.

[0073] Since the core voltage of the controller unit is unaffected by fluctuations in the power supply voltage Vcc, changes in the sampled value of the core voltage can accurately reflect fluctuations in the power supply voltage. Using this 'known stable' internal voltage as a probe, the state of the ADC reference voltage (i.e., the system power supply) can be inferred by observing changes in its 'digital sampled value' on the ADC.

[0074] Although the physical voltage of the core voltage is stable and does not change with the supply voltage V CC Fluctuating and changing, the embodiments of this application continuously collect its ADC digital output value (D core_measure The stable voltage sample value of the digital quantity), while the digital quantity acquired by the ADC will be affected by V. CC The decrease in voltage causes a drop in the ADC's reference voltage, which in turn changes the voltage. For example, due to the ADC's reference voltage V... ref (Usually from power supply voltage V) CC The value of the digital quantity (D) obtained when sampling the stable core voltage decreases accordingly. core_measure On the contrary, it increases.

[0075] Therefore, the embodiments of this application monitor the changes in the core voltage of the microcontroller unit in real time.

[0076] Exemplarily, the analog-to-digital converter (ADC) is used to acquire the core voltage of the microcontroller unit in real time to obtain a stable voltage sample value. Exemplarily, the ADC is used to acquire the voltage of the voltage regulator inside the microcontroller unit (MCU) to obtain a stable voltage sample value. For example, through the ADC inside the microcontroller unit... The REFINT channel periodically samples the core voltage to obtain a stable voltage sample value. In this embodiment, the power supply voltage fluctuation is detected based on the MCU core voltage (also known as the main circuit current fluctuation), and the core voltage is used to infer the power supply voltage. Fluctuations can be avoided without adding any additional hardware, achieving zero hardware cost.

[0077] The analog-to-digital converter is used to collect the current in the main circuit in real time to obtain the sampled value of the main circuit current.

[0078] S200: Determine whether to start the multi-level dynamic calibration algorithm based on the stable voltage sample value and the acquired reference voltage.

[0079] The stable voltage sample value is compared with the current reference voltage. If the deviation exceeds the preset fluctuation tolerance threshold, the multi-level dynamic calibration algorithm is activated; otherwise, the multi-level dynamic calibration algorithm is not activated.

[0080] For example, based on the digital quantity of the kernel voltage sample value core_measure and the digital quantity of the current reference voltage core_CAL The comparison is performed, and if the fluctuation tolerance threshold is exceeded, a calibration calculation is initiated.

[0081] For example, when the deviation of the digital value of the stable voltage sample from the digital value of the current reference voltage exceeds the fluctuation tolerance threshold, a calibration calculation is initiated.

[0082] Exemplary, the digital quantity of the stable voltage sample value ( core_measure ) and the digital quantity of the reference voltage ( core_CAL The comparison is performed, and if the comparison value exceeds the fluctuation tolerance threshold, a multi-level dynamic calibration algorithm is activated. The multi-level dynamic calibration algorithm is used to calibrate the current in the main circuit of the analog-to-digital converter in real time.

[0083] S300, if the multi-level dynamic calibration algorithm is activated, the fluctuation level of the circuit breaker's power supply voltage is obtained. Based on the calibration value, the sampled value of the main circuit current, and the fluctuation level, corresponding calibration processing is performed to obtain the main circuit current calibration value, which is used as the actual sampled value collected by the analog-to-digital converter from the main circuit. This improves the accuracy of measuring the main circuit current.

[0084] Since fluctuations in the MCU's power supply voltage cause fluctuations in the main circuit current sampling value, the fluctuation level corresponding to the main circuit current sampling value is also called the power supply voltage fluctuation level.

[0085] Multi-level dynamic calibration algorithm refers to dividing the system into multiple levels based on fluctuations, with different calibration processes applied to different levels.

[0086] In one embodiment, the fluctuation level of the power supply voltage of the circuit breaker is obtained by the following method:

[0087] When a deviation between the stable voltage sample value and the reference voltage is detected, the fluctuation level of the power supply voltage of the circuit breaker is determined.

[0088] When the deviation of the core voltage digital value from the factory calibration value is detected to be within a preset moderate fluctuation range, the nonlinear error compensation mode is entered.

[0089] Exemplary, the fluctuation level of the circuit breaker power supply voltage is determined based on the deviation and a preset fluctuation boundary value. The fluctuation boundary value is obtained through experimental data calibration, and this embodiment of the application does not impose limitations on it.

[0090] The fluctuation state of the circuit breaker power supply voltage is divided into multiple levels, resulting in multiple fluctuation grades. For example, fluctuation grades include slight fluctuation, moderate fluctuation, and severe fluctuation.

[0091] Slight fluctuations: The deviation is less than the preset first fluctuation boundary value, and the fluctuation amplitude is small.

[0092] Moderate fluctuation: The deviation is within the set fluctuation boundary value range, and the fluctuation amplitude is moderate. For example, the fluctuation amplitude is between ±3% and ±8%, and the duration is less than 10 seconds.

[0093] Severe fluctuation: The deviation is greater than the preset second fluctuation boundary value, and the fluctuation amplitude is large.

[0094] In one implementation, such as Figure 2 As shown, in step S300, the calibration process based on the calibration value and the main circuit current sampling value to obtain the main circuit current calibration value includes:

[0095] S310, if the fluctuation level is slight fluctuation, then:

[0096] The calibration value is determined based on the voltage ratio of the reference voltage to the stable voltage sample value; the calibration value is obtained by performing mathematical calculations on the calibration value and the main circuit current sample value.

[0097] In other words, when the fluctuation level is slight, the fluctuation of the main circuit current is caused by linearity error, and therefore calibration is performed based on the proportional correction method composed of the reference voltage and the sampled value of the stable voltage.

[0098] As an example, the calibration values ​​use calibration coefficients, and the main circuit current calibration value is calculated using the following formula:

[0099]

[0100] D I_offset =K× I_measure

[0101] Where K represents the calibration coefficient; core_CALA digital quantity representing the reference voltage; core_measure This represents the digital quantity of the collected core voltage sample value; D I_offset A digital quantity representing the calibration value of the main circuit current. I_measure This represents the digital value of the sampled main circuit current.

[0102] S320, if the volatility level is moderate volatility, then:

[0103] The calibration value is calculated using a combination of table lookup and piecewise linear interpolation based on the voltage ratio of the reference voltage to the sampled stable voltage. The calibration value is then obtained by performing mathematical operations on the calibration value and the sampled main circuit current.

[0104] For example, calculating the digital quantity (D) of the currently acquired kernel voltage sample value. core_measure The voltage ratio is the voltage between the reference voltage and the reference voltage. This voltage ratio reflects the degree of voltage fluctuation in the power supply.

[0105] For example:

[0106] voltage_ratio=1.0 indicates that the power supply voltage is stable and without fluctuations;

[0107] A voltage_ratio of 0.85 indicates that the power supply voltage has dropped by approximately 15%, which is considered a moderate fluctuation.

[0108] When the circuit breaker system detects a specific voltage ratio, the original sampled main circuit current value needs to be calibrated based on the corresponding calibration value. This can be achieved by adding a calibration value or multiplying the main circuit current sampled value by a calibration factor. This calibration value is used to correct for measurement errors in the main circuit current caused by power supply voltage fluctuations.

[0109] In step S320, the calibration value is calculated using a combination of table lookup and piecewise linear interpolation, including:

[0110] The voltage ratio is matched and searched in a pre-stored calibration value table;

[0111] If a match search fails, the corresponding calibration deviation value is calculated using piecewise linear interpolation between two adjacent entries, and used as the calibration value.

[0112] By way of example, a matching lookup is performed based on the voltage ratio in a pre-calibrated calibration value table stored in non-volatile memory, wherein the calibration value table contains multiple calibration values ​​arranged in ascending or descending order of voltage ratio.

[0113] If the voltage ratio does not exactly match any one of them, the piecewise linear interpolation method between two adjacent table entries is used to calculate the corresponding calibration value. For example, if two adjacent records (r1, k1) and (r2, k2) are obtained during table lookup, and r1 < voltage_ratio < r2, the calibration deviation value is calculated according to the following formula:

[0114] comp offset = k1 + (voltage_ratio - r1) × (k2 - k1) ÷ (r2 - r1)

[0115] The original sampled digital quantity of the main circuit current is calibrated and corrected by using the calculated calibration value, and the measurement result of the main circuit current closer to the true value is output.

[0116] It can be understood that the embodiment of the present application also needs to pre-store the mapping relationship between the calibration value and the voltage ratio. The voltage ratio range of the reference voltage and the stable voltage sampling value is divided into multiple stages, and a calibration value corresponding to each stage is set at the starting point of each stage. The mapping relationship is constructed based on the starting point of each stage and the calibration value corresponding to each stage. The relationship between the voltage ratio and the calibration value in this mapping relationship is obtained based on a lot of circuit breaker experiments and calibration, and the present application does not limit this. For example, if the calibration value is a calibration coefficient, then the mapping relationship is the mapping relationship between the calibration coefficient and the voltage ratio, as shown in Table 1:

[0117] Table 1 Mapping Relationship between Calibration Coefficient and Voltage Ratio - Calibration Value Table

[0118]

[0119] For the convenience of quick query, the embodiment of the present application uses an array to store the mapping relationship between the calibration coefficient and the voltage ratio, and uses a structure to store the calculated voltage ratio.

[0120] For example, a structure struct{

[0121] float voltage_ratio; / / Voltage ratio

[0122] float comp offset; / / Calibration deviation value

[0123] }LUT_t;

[0124] A preset array const LUT_t K_LUT[] = {{0.80, comp offset1}, {0.81, comp offset2}, …, {0.95, comp offset16}}.

[0125] Among them, {0.80, comp offset1}: indicates that when D core_measure / D core_CAL =0.80, meaning that when the power supply is severely insufficient, it should be used. comp offset1 As a calibration value. {0.95, comp offset16}: This indicates that when the voltage ratio is 0.95 (slightly decreased), the following applies: comp offset16 As a calibration value.

[0126] S330, if the fluctuation level is severe fluctuation, then the multi-level dynamic calibration algorithm is turned off. Severe fluctuation is considered a serious energy deficiency, and the main circuit current is not calculated.

[0127] In this embodiment, a three-level segmented adaptive compensation strategy is adopted, namely, linear calibration is used for slight fluctuations, nonlinear calibration is used for moderate fluctuations, and intelligent freezing is performed for severe fluctuations to avoid 99% of false tripping.

[0128] In one embodiment, to improve adaptability and address the issues of device aging and temperature drift after long-term operation, the method further includes:

[0129] S400: When it is detected that the main circuit current has entered a stable current state, the current reference voltage is adaptively updated based on the currently collected stable voltage sample value and the adaptive learning rate.

[0130] When the main circuit current calibration value is detected to jump from a low value to a value higher than the set high threshold and enter a stable state, the adaptive learning mechanism is triggered to update the reference voltage in a weighted average manner based on the currently collected kernel voltage sample value.

[0131] In other words, the main circuit current is monitored in real time based on the main circuit current calibration value, and it is determined whether the current has entered a stable state according to preset conditions. In the stable current state, the MCU receives sufficient and stable energy.

[0132] By periodically identifying when the circuit breaker system enters a 'sufficient and stable' operating state (stable state), a high-reliability core voltage is obtained in this stable state, and the reference voltage used for offset correction is updated accordingly. Subsequent acquisitions of the main circuit current will be digitally calibrated based on this reference voltage, thereby improving measurement consistency and protection action accuracy during long-term operation.

[0133] In other words, updating the reference voltage is used to calibrate errors in the analog-to-digital converter (ADC), such as zero-point offset or gain error due to power supply voltage instability, to improve the accuracy of main loop current measurements. This calibration process is performed in the digital domain and does not involve current injection or power conditioning of external circuitry, thereby reducing costs.

[0134] Furthermore, such as Figure 3 As shown, the adaptive update of the current reference voltage based on the currently acquired stable voltage sample value and the adaptive learning rate includes:

[0135] S410, when the main circuit current is in a stable state, acquire multiple stable voltage sample values ​​and calculate the average voltage; for example, in a stable state, acquire the core voltage of the MCU at multiple times to obtain multiple core voltage sample values, and calculate the average voltage of the multiple core voltage sample values.

[0136] S420, based on the average voltage, the current reference voltage, and the weighting coefficients determined based on the adaptive learning rate, a weighted average calculation is performed to obtain the updated reference voltage.

[0137] As an example, the updated reference voltage is calculated using the following formula:

[0138] core_new =(1-LEARN_RATE)× core_CAL +LEARN_RATE× core_AVG

[0139] in, core_new This represents the updated reference voltage, and LEARN_RATE represents the adaptive learning rate. core_CAL This indicates the current reference voltage. core_AVG This represents the average voltage under steady-state conditions.

[0140] Furthermore, the method in this embodiment further includes: performing anomaly detection on the updated reference voltage, and updating the current reference voltage after the anomaly detection passes. For example, calculating... core_new This does not fall within the normal range.

[0141] Furthermore, to avoid frequent flash erasure and rewriting, the method in this application embodiment also includes:

[0142] The updated reference voltage is stored in the flash memory of the circuit breaker at a preset period.

[0143] Furthermore, in this embodiment, the initial reference voltage is a core voltage pre-measured under stable external power supply and standard environmental conditions before the circuit breaker leaves the factory, and it is stored in the circuit breaker's memory. For example, the memory is non-volatile memory (Flash), which can be the Flash integrated inside the MCU or an external Flash.

[0144] As an example, before the circuit breaker products leave the factory, they are powered by an external high-precision regulated power supply. Maintain the voltage within the range of 3.3V ± 0.1% and control the ambient temperature at 25℃. Under these stable conditions, start the analog-to-digital converter (ADC) to sample the core voltage of the MCU multiple times and calculate its average value as the initial reference voltage. This initial reference voltage is then hardened and stored in Flash after CRC verification, serving as the initial reference voltage for the circuit breaker's first operation.

[0145] This application has the following advantages:

[0146] Significantly improves measurement accuracy: By calibrating the reference voltage and main circuit current, it corrects for nonlinearity and long-term aging, greatly improving the accuracy of current measurement at low current (mainly the accuracy of measuring the main circuit current).

[0147] Improved stability and reliability: Calibration reduces the probability of product malfunctions under low energy conditions, ensuring continuous power supply.

[0148] Zero hardware cost increase: This application is implemented purely in software, incurring zero additional cost. It utilizes existing resources within the MCU (core voltage stability), eliminating the need for any external voltage reference or other compensation circuitry, a significant advantage for the product.

[0149] Figure 4 A schematic diagram of an adaptive calibration device for a circuit breaker according to an embodiment of this application is shown. Exemplarily, the adaptive calibration device for the circuit breaker includes: a sampling module 410, a calibration initiation management module 420, and a calibration module 430.

[0150] The sampling module 410 is used to synchronously sample the main circuit current and the stable voltage of the microcontroller unit using the analog-to-digital converter, and obtain the sampled value of the main circuit current and the sampled value of the stable voltage accordingly.

[0151] The calibration startup management module 420 is used to determine whether to start the multi-level dynamic calibration algorithm based on the stable voltage sample value and the acquired reference voltage.

[0152] The calibration module 430 is used to obtain the fluctuation level of the power supply voltage of the circuit breaker if the multi-level dynamic calibration algorithm is activated, and perform corresponding calibration processing based on the calibration value, the main circuit current sampling value and the fluctuation level to obtain the main circuit current calibration value, which is used as the real sampling value collected by the analog-to-digital converter from the main circuit.

[0153] It is understood that the device in this embodiment corresponds to the adaptive calibration method of the circuit breaker in the above embodiment, and the options in the above embodiment are also applicable to this embodiment, so they will not be described again here.

[0154] This application also provides a terminal device, exemplary of which includes a processor and a memory, wherein the memory stores a computer program, and the processor executes the computer program to cause the terminal device to perform the functions of the various modules in the aforementioned adaptive calibration method for circuit breakers or the aforementioned adaptive calibration device for circuit breakers. Exemplarily, the terminal device is a circuit breaker. The processor is a microcontroller unit.

[0155] The processor can be an integrated circuit chip with signal processing capabilities. The processor can be a general-purpose processor, including at least one of a Central Processing Unit (CPU), Graphics Processing Unit (GPU), Network Processor (NP), Digital Signal Processor (DSP), Application-Specific Integrated Circuit (ASIC), Field-Programmable Gate Array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. The general-purpose processor can be a microprocessor or any conventional processor, capable of implementing or executing the methods, steps, and logic block diagrams disclosed in the embodiments of this application.

[0156] The memory can be, but is not limited to, Random Access Memory (RAM), Read Only Memory (ROM), Programmable Read-Only Memory (PROM), Erasable Programmable Read-Only Memory (EPROM), Electrically Erasable Programmable Read-Only Memory (EEPROM), etc. The memory is used to store computer programs, and the processor can execute the computer programs accordingly after receiving execution instructions.

[0157] This application also provides a computer-readable storage medium for storing the computer program used in the aforementioned terminal device. For example, the computer-readable storage medium may include, but is not limited to, various media capable of storing program code, such as a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0158] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can also be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the flowcharts and block diagrams in the accompanying drawings show the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that, in alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagram and / or flowchart, and combinations of blocks in the block diagram and / or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0159] In addition, the functional modules or units in the various embodiments of this application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0160] If the aforementioned functions are implemented as software functional modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a smartphone, personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application.

[0161] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A method of adaptive calibration of a circuit breaker, characterized by, The circuit breaker comprises a microcontroller unit and an analog-to-digital converter, and the method comprises: synchronously sampling the main loop current and the stable voltage of the microcontroller unit by using the analog-to-digital converter, so as to obtain a main loop current sampling value and a stable voltage sampling value; judging whether to start a multi-stage dynamic calibration algorithm according to the stable voltage sampling value and a reference voltage obtained; if the multi-stage dynamic calibration algorithm is started, obtaining a fluctuation level of a power supply voltage of the circuit breaker, and performing corresponding calibration processing based on a calibration value, the main loop current sampling value and the fluctuation level to obtain a main loop current calibration value as a real sampling value collected by the analog-to-digital converter from the main loop; wherein the calibration processing based on the calibration value, the main loop current sampling value and the fluctuation level to obtain the main loop current calibration value comprises: if the fluctuation level is slight fluctuation, then: determining the calibration value according to a voltage ratio of the reference voltage to the stable voltage sampling value, and performing calibration processing of mathematical operation based on the calibration value and the main loop current sampling value to obtain the main loop current calibration value; if the fluctuation level is moderate fluctuation, then: calculating the calibration value by using a table lookup method and a piecewise linear interpolation method in combination according to the voltage ratio of the reference voltage to the stable voltage sampling value, and performing calibration processing of mathematical calculation based on the calibration value and the main loop current sampling value to obtain the main loop current calibration; if the fluctuation level is serious fluctuation, then the multi-stage dynamic calibration algorithm is closed.

2. The method of adaptive calibration of a circuit breaker of claim 1, wherein, the calculation of the calibration value by using the table lookup method and the piecewise linear interpolation method in combination comprises: matching lookup in a pre-stored calibration value table according to the voltage ratio; if the matching lookup fails, then a piecewise linear interpolation method between adjacent two table items is used to calculate a corresponding calibration deviation value as the calibration value.

3. The method of adaptive calibration of a circuit breaker of claim 1, wherein, The method further comprises: when it is identified that the main loop current enters a current stable state, adaptively updating a current reference voltage based on the stable voltage sampling value currently collected and an adaptive learning rate.

4. The method of adaptive calibration of a circuit breaker of claim 3, wherein, the adaptive updating of the current reference voltage based on the stable voltage sampling value currently collected and the adaptive learning rate comprises: under the condition that the main loop current is in a stable state, collecting a plurality of stable voltage sampling values and calculating an average voltage; performing weighted average calculation based on the average voltage, the current reference voltage and a weight coefficient determined based on the adaptive learning rate to obtain an updated reference voltage.

5. The method of adaptive calibration of a circuit breaker of claim 4, wherein, the updated reference voltage is calculated by using the following formula: core_new = (1 - LEARN_RATE) x core_CAL + LEARN_RATE x core_AVG wherein, core_new denotes the updated reference voltage, LEARN_RATE denotes an adaptive learning rate, core_CAL denotes the current reference voltage, core_AVG denotes the average voltage in the steady state.

6. The method of adaptive calibration of a circuit breaker of claim 1, wherein, The method further comprises the following two items: first item: the stable voltage of the microcontroller unit adopts a core voltage of the microcontroller unit; the synchronous sampling of the main loop current and the stable voltage of the microcontroller unit by using the analog-to-d digital converter comprises: collecting a voltage of a voltage regulator inside the microcontroller unit by using the analog-to-digital converter to obtain a core voltage sampling value as the stable voltage sampling value; Secondly, the initial reference voltage is a core voltage determined in advance before the circuit breaker leaves the factory under the condition of external stable power supply and standard environment, and is stored in the memory of the circuit breaker; Thirdly, The updated reference voltage is stored in the memory of the circuit breaker based on a preset period; Fourthly, the updated reference voltage is subjected to abnormality detection, and the current reference voltage is updated when the abnormality detection passes.

7. The method of adaptive calibration of a circuit breaker according to any of claims 1-6, characterized in that, The fluctuation level of the power supply voltage of the circuit breaker is obtained by the following method, comprising: When the deviation of the stable voltage sampling value and the reference voltage is detected, the fluctuation level of the power supply voltage of the circuit breaker is determined.

8. An adaptive calibration device for a circuit breaker, characterized by The circuit breaker comprises a microcontroller unit and an analog-to-digital converter, and the device comprises: A sampling module is configured to synchronously sample the main loop current and the stable voltage of the microcontroller unit by using the analog-to-digital converter, so as to obtain a main loop current sampling value and a stable voltage sampling value; A calibration start management module is configured to determine whether to start a multi-stage dynamic calibration algorithm according to the stable voltage sampling value and the obtained reference voltage; A calibration module is configured to, if the multi-stage dynamic calibration algorithm is started, obtain the fluctuation level of the power supply voltage of the circuit breaker, perform corresponding calibration processing based on a calibration value, the main loop current sampling value and the fluctuation level, and obtain a main loop current calibration value as a real sampling value collected by the analog-to-digital converter from the main loop; The corresponding calibration processing based on the calibration value, the main loop current sampling value and the fluctuation level to obtain the main loop current calibration value comprises: If the fluctuation level is slight fluctuation, then: The calibration value is determined according to the voltage ratio of the reference voltage and the stable voltage sampling value, and the main loop current calibration value is obtained by performing mathematical operation calibration processing according to the calibration value and the main loop current sampling value; If the fluctuation level is moderate fluctuation, then: The calibration value is calculated by using a combination of a lookup table method and a piecewise linear interpolation method according to the voltage ratio of the reference voltage and the stable voltage sampling value, and the main loop current calibration value is obtained by performing mathematical operation calibration processing according to the calibration value and the main loop current sampling value; If the fluctuation level is severe fluctuation, then the multi-stage dynamic calibration algorithm is closed.

9. A circuit breaker characterized by, The circuit breaker comprises a microcontroller unit, an analog-to-digital converter and a memory, the memory stores a computer program, and the microcontroller unit is configured to execute the computer program to implement the adaptive calibration method of the circuit breaker according to any one of claims 1-7.

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