Chip system for realizing user-level calibration-free electric energy metering and calibration method thereof

Abstract

The invention provides a chip system for realizing user-level calibration-free electric energy metering and a calibration method thereof, and the chip comprises a current sampling module (101), a temperature measurement and temperature drift compensation module (102), a storage module (103) and a communication module (104) which are disposed in the chip. Wherein the current sampling module (101) is used for sampling an input current; the temperature measurement and temperature drift compensation module (102) is used for performing temperature drift compensation on the current sampling module (101); the storage module (103) is used for storing chip calibration parameters during delivery; the communication module (104) is used for communication between the chip and external equipment; according to the calibration method, the chip is adopted for calibration. The direct-current signal source is used as a signal source for chip-level error calibration, so that the requirement of the signal source is greatly reduced, and the efficiency is improved; and chip-level error calibration is adopted, user-level errors are free of calibration, use by a user is facilitated, and the product production efficiency of the user is improved.

Description

Technical Field

[0001] The present invention relates to an electric energy metering chip system and a calibration method thereof, in particular to a chip system and a calibration method thereof for realizing user-level calibration-free electric energy metering. Background Art

[0002] This section merely provides background information related to the present disclosure and is not necessarily prior art.

[0003] Energy metering chips are indispensable in the field of energy metering. At present, various types of energy metering chips emerge in an endless stream, and all need to be designed into products (products include metering chips and peripheral acquisition circuits), and then the metering chips are calibrated one-to-one through an external MCU. The errors introduced include not only the chip itself, but also the errors of the current and voltage acquisition circuits.

[0004] Since the current electric energy metering products are in various forms, it is difficult to perform one-to-one electric energy error calibration on many products in batches, which greatly affects the production efficiency of the products. Therefore, how to improve the production efficiency of electric energy metering products has become a technical problem that needs to be solved urgently by technical personnel in this field, and the most critical point is the error calibration process.

[0005] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0006] Purpose of the invention: The technical problem to be solved by the present invention is to provide a chip system and a calibration method thereof for realizing user-level calibration-free electric energy metering in view of the deficiencies in the prior art.

[0007] In order to solve the above technical problems, the present invention discloses a chip system for realizing user-level calibration-free electric energy metering and a calibration method thereof, wherein the chip system comprises:

[0008] A current sampling module, a temperature measurement and temperature drift compensation module, a storage module and a communication module are arranged in the chip;

[0009] in,

[0010] The current sampling module is used to sample the input current;

[0011] The temperature measurement and temperature drift compensation module is used to perform temperature drift compensation on the current sampling module;

[0012] The storage module is used to store the chip calibration parameters at the factory;

[0013] The communication module is used for communication between the chip and external equipment.

[0014] Furthermore, the current sampling module is a sampling resistor implemented by using a chip frame base island.

[0015] Furthermore, the performing temperature drift compensation on the current sampling module includes:

[0016] Step a1, testing the temperature rise characteristics of the current sampling resistor in the current sampling module, that is, testing the resistance of the current sampling resistor within a preset temperature range, and obtaining the fitting temperature drift formula as follows:

[0017] R (T) =R0[1+(T-T0)×K]

[0018] Among them, R (T) Indicates the resistance of the current sampling resistor at the current temperature, R0 indicates the resistance of the current sampling resistor at normal temperature, T indicates the current temperature, T0 indicates the typical temperature, and K indicates the ratio of the resistance change rate of the current sampling resistor to the temperature, which is determined by the material properties;

[0019] Step a2: according to the resistance value R of the current sampling resistor at the current temperature (T) , calculate the exact current value as follows:

[0020]

[0021] Among them, V (T) is the voltage value acquired by the current chip, and I is the precise current value;

[0022] Step a3: calibrate the current value currently measured according to the precise current value I.

[0023] Furthermore, the storage module is an Efuse storage module.

[0024] Furthermore, the storage module stores the chip calibration parameters at the factory, including:

[0025] Step b1, turning on and adjusting the signal source for calibration, measuring the current and voltage outputted by the signal source as standard values ​​for current and voltage calibration;

[0026] Step b2, using the electric energy metering chip to measure the current and voltage of the power supply to obtain current and voltage measurement values;

[0027] Step b3, calculating the current and voltage errors according to the current and voltage calibration values ​​and the current and voltage measurement values;

[0028] Step b4, storing the calibration value of the current and voltage errors in the storage module (103) for calibrating the electric energy metering chip.

[0029] Furthermore, the signal source described in step b1 is a DC signal power supply.

[0030] Furthermore, the communication module is a UART module.

[0031] Furthermore, the communication module initiates metering data push when the voltage passes through zero point, as follows:

[0032] Whether the voltage signal passes through zero is detected according to the signal waveform of the voltage measurement channel in the electric energy metering chip. If it is detected that the voltage signal passes through zero, metering data push is initiated through the communication module.

[0033] Furthermore, the sampling resistor is 0.1 mΩ to 5 mΩ.

[0034] The present invention also proposes a calibration method for a user-level calibration-free electric energy metering chip, which uses the aforementioned chip for calibration, and includes the following steps:

[0035] Step 1, turning on a DC signal source for calibrating the metering chip;

[0036] Step 2, applying accurate voltage and current signals output by a DC signal source to the metering chip, wherein the voltage signal is input to the metering chip through an electrical sampling circuit, and the current signal is directly input to the metering chip;

[0037] Step 3: Use the temperature measurement and temperature drift compensation module to perform temperature drift compensation on the metering chip and write the compensation value;

[0038] Step 4, receiving the measurement data before the measurement chip is calibrated;

[0039] Step 5, judging whether the voltage and current errors are within the calibrable range according to the measurement data before calibration;

[0040] Step 6: If the voltage and current errors are within the calibrable range, the voltage and current calibration parameters are calculated and stored; otherwise, the metering chip is judged as a defective product;

[0041] Step 7, calibrating the metering chip using the voltage and current calibration parameters, and judging whether the voltage and current errors after calibration are within the standard range according to the calibrated metering data;

[0042] Step 8: If the voltage and current errors are within the standard range, the calibration is completed; otherwise, the metering chip is judged as a defective product.

[0043] Beneficial effects:

[0044] 1. The electric energy metering chip proposed in the present invention integrates a current sampling resistor and a current sampling circuit, simplifies the traditional current sampling circuit, and reduces the cost.

[0045] 2. The electric energy metering proposed in the present invention aims at the temperature rise of the built-in current sampling resistor, designs a high-performance temperature measurement and temperature drift compensation circuit, realizes the temperature drift compensation of the sampling resistor, and realizes over-temperature alarm at the same time.

[0046] 3. The present invention adopts Efuse technology to store chip operation parameters and error calibration parameters inside the chip.

[0047] 4. The present invention actively initiates metering data push when the voltage crosses the zero point, and a single bus realizes data communication and the output of zero-crossing signals, thereby simplifying the communication circuit. When using the system, users only need to complete the protocol docking.

[0048] 5. The present invention uses a DC signal source as a signal source for chip-level error calibration, which greatly reduces the requirements for the error calibration standard signal source and improves the calibration efficiency.

[0049] 6. The present invention can calibrate chip-level errors, and user-level errors do not need to be calibrated, which is convenient for users to use and improves the production efficiency of user products. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments, and the above and / or other advantages of the present invention will become more clear.

[0051] Figure 1 It is a schematic diagram of the chip architecture of the present invention.

[0052] Figure 2 is a framework diagram of calibration in an embodiment.

[0053] Figure 3 It is a schematic diagram of the temperature drift curve.

[0054] Figure 4 This is a schematic diagram of the chip's working principle.

[0055] Figure 5 This is a schematic diagram of voltage zero-crossing triggering.

[0056] Figure 6 Schematic diagram of the calibration method of the present invention. DETAILED DESCRIPTION

[0057] The present invention designs a user-level calibration-free electric energy metering chip, and the error calibration of the metering chip is completed at the chip level. The error calibration is completed at the chip level. Due to the uniform chip shape, the error calibration can be completed efficiently. After leaving the factory, when the user uses this electric energy metering chip, there is no need to perform electric energy metering error calibration. This improves the production efficiency of electric energy metering products and simplifies the user's production process. The technical solution includes:

[0058] 1. Integrated internal current sampling circuit, including current sampling resistor (0.1mΩ~5mΩ):

[0059] The internal sampling resistor is implemented by a chip frame base island. The shape of the sampling resistor is not limited to a regular shape, but can also be arbitrarily defined in various shapes according to the actual chip frame size and the resistance range of the sampling resistor.

[0060] 2. In view of the temperature rise of the built-in current sampling resistor, a high-performance temperature measurement and temperature drift compensation circuit is designed to realize the temperature drift compensation of the sampling resistor and realize the over-temperature alarm. The over-temperature alarm is reflected in the actively reported data in the form of a status word, as follows:

[0061] First, the temperature rise characteristics of the selected metal material of the current sampling resistor are tested, and the resistance of the current sampling resistor is tested from low temperature -40℃ to high temperature 100℃, and the temperature drift formula is fitted:

[0062] R (T) =R0[1+(T-T0)*K]

[0063] Among them, R (T) Indicates: the resistance of the current sampling resistor at the current temperature; R0 indicates: the resistance of the current sampling resistor at 23℃±2℃ (reference temperature range, the normal temperature range in the current technical standards); T indicates: the current temperature value; T0 indicates: the typical temperature 25℃; K indicates: the change rate of the current sampling resistor / ℃, and the K value is determined by the characteristics of the metal material;

[0064] The temperature drift curve of the resistance value and temperature of the fitting current sampling resistor is as follows: Figure 3 As shown, the horizontal axis T represents the temperature value and the vertical axis R represents the resistance value.

[0065] according to:

[0066] V (T) =IR (T)

[0067] The measurement chip collects the differential voltage of the current channel. Because I = V (T) / R (T) , V (T) The voltage value of the chip is known after acquisition. As long as R (T) The accurate value of I can be obtained.

[0068] To get R (T) To get the accurate value of R, we first need a high-performance temperature measurement circuit to measure the current temperature T, and then use the temperature drift formula to get the R value. (T) According to the temperature drift formula, the higher the accuracy of the temperature measurement circuit, the higher the algorithm fit of the temperature drift formula, and the higher the accuracy of R (T) The more precise the value.

[0069] 3. Use Efuse technology to store chip operating parameters and error calibration parameters inside the chip:

[0070] The reason why Efuse technology is used here is that users do not need to participate in any parameter setting, that is, the parameters of the metering chip are fixed after leaving the factory, and using Efuse technology is the most cost-effective method. Other technologies can also achieve parameter storage and meet technical effects, but the cost will be much higher, and the process of the storage chip and the process of the metering chip need to match, and the design will be more complicated.

[0071] Efuse can only perform a write operation once.

[0072] The so-called error calibration parameters are the errors of one voltage and one current ∑-ΔADC. The error of voltage ∑-ΔADC refers to the error value obtained by comparing the actual input signal of the voltage channel with the signal collected by the chip ADC; the error of current ∑-ΔADC refers to the error value obtained by comparing the actual input signal of the current channel with the signal collected by the chip ADC. At the same time, the error is caused by the temperature drift of the built-in current sampling resistor caused by different current signal sizes. The chip calibrates the error of current ∑-ΔADC through error calibration and temperature drift compensation of current ∑-ΔADC.

[0073] The actual input voltage signal value of the voltage channel is X (mV), and the signal value output after chip acquisition is X1, while the corresponding signal value of the theoretical voltage signal value X (mV) is X2, so the voltage channel error is ((X1-X2) / X2)*100%; the actual input current of the current channel is Y (A), and the signal value output after acquisition by the built-in current sampling circuit chip is Y1, while the corresponding signal value of the theoretical current Y (A) is Y2, so the current channel error is ((Y1-Y2) / Y2)*100%.

[0074] Here, we only need to calibrate the ADC error of each chip to ensure the consistency of the ADC error of all chips. Since the linearity of the chip ADC error fully meets the measurement accuracy requirements, the voltage and current ADC errors only need a constant Δ value calibration to meet the measurement accuracy requirements. The calibration Δ constant value of the voltage and current ADC errors is stored in Efuse.

[0075] 4. It can work normally without external MCU participation;

[0076] Conventional metering chips require an external MCU to configure their parameters and functions before they can start to normally collect external signal values; the present invention adopts a method of solidifying the chip operation parameter design, that is, after the chip is normally powered on, it starts to collect the signal values ​​of the voltage and current channels and starts working according to the solidified working state without the participation of an external MCU.

[0077] 5. The present invention actively initiates metering data push when the voltage crosses zero (the metering chip is to be designed together with the PCBA of the actual product, and the data pushed here is pushed to the MCU on the actual product), and a single bus realizes data communication and the output of zero-crossing signals.

[0078] The present invention detects whether the voltage signal passes through zero according to the signal waveform of the voltage channel collected in real time, and initiates data push through the UART port when it is detected that the voltage signal passes through zero.

[0079] Metering data format: over-temperature warning + voltage signal value + current signal value + active power signal value + reactive power signal value + frequency signal value + pulse count value;

[0080] The voltage zero crossing point is synchronously aligned with the first signal bit of the metering data reporting frame; Figure 5 , where the horizontal axis Tu represents the cycle time of the AC voltage, and Vu is the AC voltage value; the horizontal axis Td represents the time value of data communication, and Vu is the signal amplitude of data communication.

[0081] 501 indicates the moment when the AC voltage crosses zero, and 502 indicates the first low-level signal bit of the measurement data reporting frame; the start time of the first low-level signal of 501 and 502 is synchronized.

[0082] The MCU can obtain the zero-crossing signal of the AC voltage by collecting the first low-level signal of the metering data reporting frame.

[0083] 6. The original values ​​of the voltage ∑-ΔADC signal and the current ∑-ΔADC signal collected by the metering chip can be read through the UART reserved for chip testing. This function can use the present invention as a universal ADC chip.

[0084] 7. Use a DC signal source as the signal source for chip-level error calibration, calibrate the chip's current and voltage ADC errors within ±1%, and ensure that the chip's current and voltage ADC sampling consistency is within ±1%.

[0085] Embodiment 1:

[0086] In the present invention, the electric energy metering chip designed is as follows Figure 1 As shown: 101 is a current sampling circuit, 102 is a temperature measurement and temperature drift compensation circuit, 103 is an Efuse module, 104 is a UART module, and a voltage sampling circuit;

[0087] Power module: 220VAC to 3.3VDC power module

[0088] MCU: Any general MCU with a UART interface will do, such as the STM32F0 series chips.

[0089] like Figure 4 As shown in the figure, it is a circuit schematic diagram of the working of the metering chip, wherein the voltage sampling circuit is composed of a first resistor R1 ... an nth resistor Rn, a voltage signal voltage dividing resistor Rv, and a voltage signal filtering capacitor Cv. The first resistor R1 is connected in series with ... the nth resistor Rn, and then connected in parallel with the voltage signal voltage dividing resistor Rv and the voltage signal filtering capacitor Cv. The signals at both ends of the voltage signal voltage dividing resistor Rv are respectively connected to the Vp and Vn pins of the metering chip; the power module provides a 3.3V power supply to the metering chip; the power pin of the metering chip is connected to a filtering capacitor Cvcc; the Tx pin of the metering chip is connected to the Rx pin of the MCU.

[0090] Figure 4 In the figure, 3.3V is the typical operating voltage of the chip. The chip can actually input a wide voltage of 2.5V to 5.5V.

[0091] like Figure 4 As shown:

[0092] The live wire Lin is connected to the current input pin of the metering chip, and the live wire Lout is connected to the current output pin of the metering chip. The live wire Lin and the neutral wire N are simultaneously connected to the voltage sampling circuit, and the differential voltage signal of the voltage sampling circuit is respectively connected to the voltage signal input pins Vp and Vn of the metering chip. The TX pin of the metering chip UART can be connected to the RX pin of the MCU's UART.

[0093] According to the above wiring method, after the metering chip is powered on, the metering chip will read the operating parameters and voltage and current ADC error calibration values ​​stored in Efuse and load them into the operating register of the metering chip, so that the metering chip can operate in the set working state and complete the correction of the voltage and current ADC acquisition signals; at the same time, the temperature measurement and temperature drift compensation circuit monitors the temperature changes of the current sampling resistor and the chip in real time, and performs temperature drift compensation on the current sampling in real time according to the temperature changes.

[0094] At the same time, the TX of UART will initiate the metering data push when the voltage passes through zero according to the set time interval. The pushed content includes over-temperature warning, voltage signal value, current signal value, active power signal value, reactive power signal value, frequency signal value, and pulse count value. The MCU can receive the metering data actively pushed by the metering chip through the RX pin of UART.

[0095] The active power signal value, reactive power signal value, frequency signal value and pulse count value are pushed out through the TX pin after being collected and processed by the metering chip. The general metering data acquisition method is responsive, and active push is rarely used; the point of the present invention is active push, and data push is initiated when the voltage crosses the zero point at the set interval time.

[0096] The user MCU processes the metering data actively pushed by the metering chip: 1. The present invention provides voltage signal value conversion coefficient K1, current signal value conversion coefficient K2, active power signal value conversion coefficient K3, reactive power signal value conversion coefficient K4, and frequency signal value conversion formula according to actual applications (all K coefficients are constants, the K value of each chip is the same, and the acquisition error of the metering chip after voltage and current ADC calibration is within the set error range, ensuring the consistency of the chip factory acquisition data. Apply a high-precision (0.05% or above) standard table AC voltage and current signal source to the calibrated metering chip, and perform a simple single multiplication calculation on the metering data pushed by the metering chip and the data of the high-precision standard table to obtain the conversion coefficient corresponding to each parameter. The consistency of the metering chip and the high-precision (0.05% or above) standard table ensure that the same K value can be provided for each metering chip), and the user MCU divides the received metering data by the corresponding K coefficient to obtain an accurate signal value. 2. Pulse count value: The pulse counter has been working since it was powered on. The metering chip integrates a metering energy bucket (the metering energy bucket is an energy accumulation circuit, and the active power is accumulated at a fixed accumulation frequency to generate an accumulated energy value.) and an energy threshold value (when the energy threshold value is determined, the corresponding pulse constant is determined. Simply put, the pulse constant is the number of pulses per kWh). Every time the energy bucket accumulates over the energy threshold value, a pulse signal will be output, and the pulse count value will increase by 1 (the pulse count value will be cleared after each power-off and power-on of the metering chip, and the pulse count value will automatically return to zero and start accumulation again if it overflows). The user MCU can obtain the energy value by performing a simple calculation on the received pulse count value. The energy value of each pulse = 1 / pulse constant.

[0097] In order to reduce the difficulty of chip-level error calibration and improve the efficiency of error calibration, a user-level calibration-free electric energy metering chip of this application uses a DC signal source as a standard signal source to implement error calibration. (Traditional electric energy metering chips all use AC signal sources as standard signal sources for error calibration; high-precision AC signal sources are large in size, expensive, and have a long output signal stabilization time. They are very troublesome to use in the chip-level error calibration process, and they take up space and start slowly, which seriously affects production efficiency.) The DC signal source has fast and stable signal output, a small device size, and even a board-level DC signal source, which can be integrated with the chip test platform, which can greatly improve the chip calibration efficiency.

[0098] Because the filter designs for signal acquisition and processing in AC metering chips and DC metering chips are different, there will be deviations when all AC metering chips are calibrated with DC signal sources.

[0099] The metering chip of the present invention directly outputs the original values ​​of the current and voltage ADC. The calibration of the metering chip is the consistency calibration of the ADC error, not the calibration of the ADC absolute error, but the consistency calibration of the ADC relative error. Therefore, the calibration can be completed by a DC signal source.

[0100] Traditional metering chips are calibrated for ADC absolute error, so they must be calibrated with an AC signal source and must be combined with an external sampling circuit to complete the entire calibration work.

[0101] Embodiment 2:

[0102] The present invention provides a method for implementing chip-level electric energy measurement calibration, such as Figure 2 As shown;

[0103] Figure 2 Middle: 201 control module 202 DC source 203 DC meter 204 metering chip

[0104] 201 control module: controls the signal output of the DC source, communicates and interacts with the DC meter, and communicates and interacts with the metering chip.

[0105] 202 DC source: output voltage and current signals to power the DC meter, metering chip and control module.

[0106] 203 DC meter: High-precision meter with voltage and current acquisition accuracy ≤ 0.2%, with RS485 communication, interacting with the control module.

[0107] 204 metering chip: collects voltage and current signals and communicates with the control module. Figure 2 The 1st pin of the metering chip 204 is the current signal input pin, the 2nd pin is the current signal output pin, the 3rd pin is the voltage signal input pin, the 4th pin is the voltage signal input pin, the 6th pin is the chip power supply VCC, the 5th pin is the power ground VSS, and the 7th pin is the UART TX pin.

[0108] 1. DC source current signal output terminal 2. DC meter current output line 3. Metering chip current output line 4. DC source outputs positive voltage signal 5. DC source outputs zero voltage signal 6. DC source power supply positive terminal 7. DC source power supply ground 8. DC source power supply positive terminal 9. DC source power supply ground 10. DC meter's RS485 bus 11. DC source communication port UART's RX pin 11. DC source communication port UART's TX pin 13. Metering chip test pin TEST1 (UART's TX pin) 14. Metering chip test pin TEST2 (UART's RX pin) 15. Metering chip's TX pin.

[0109] like Figure 2 As shown, the signal logic of the method is as follows:

[0110] One power output of the DC source 202 supplies power to the metering chip 204 and the DC meter 203 through the DC source 202 power supply positive terminal 6 and the DC source 202 power supply ground 7; another power output of the DC source 202 supplies power to the control module 201 through the DC source 202 power supply positive terminal 8 and the DC source 202 power supply ground 9;

[0111] The current signal output terminal 1 of the DC source 202 is connected to the current input terminal of the DC meter 203, the current output line 2 of the DC meter is connected to the current signal input pin of the metering chip 204, and the current output pin of the metering chip 204 is connected to the current signal input terminal of the DC source.

[0112] The DC source 202 outputs a positive voltage signal 4 which is connected to the voltage signal input pin 3 of the metering chip 204 , and the DC source 202 outputs a zero voltage signal 5 which is connected to the voltage signal input pin 4 of the metering chip 204 .

[0113] The TX pin of the UART of the control module 201 is connected to the RX pin 11 of the DC source communication port UART, and the RX pin of the UART is connected to the RX pin 12 of the DC source communication port UART; the TX pin of another group of UARTs of the control module 201 is connected to the test pin TEST2 (RX pin of the UART) of the metering chip.

[0114] The RX pin of the UART is connected to the test pin TEST1 of the metering chip (the TX pin of the UART). The RX pin of the third group of UARTs of the control module 201 is connected to the TX pin of the metering chip.

[0115] The control module 201 controls the DC source 202 to output the current signal and voltage signal within the set range. The current signal is first input to the DC meter 203 and then to the metering chip 204, and finally flows back to the DC source 202; the voltage signal is simultaneously input to the DC meter 203 and the metering chip 204; the control module 201 reads the current signal and voltage signal collected by the DC meter through the RS485 bus 10 of the DC meter, and confirms that the current signal and voltage signal output by the DC source 202 are within the set error range. If they are not within the set range, the signal output of the DC source 202 will be turned off and turned on again. If the second signal output confirmation is still not within the set range, an alarm will be sounded, indicating that the DC source or DC meter is abnormal and the fault must be checked.

[0116] The metering chip 204 actively sends the current signal and voltage signal conversion values ​​collected by the current and voltage ADC to the control module 201 through pin 7. The control module 201 compares the signal value reported by the metering chip 204 with the current signal and voltage signal output by the set DC source 202 and calculates the error, and then calculates the calibration Δ constant value of the voltage and current ADC error based on the error.

[0117] The control module 201 uses the measurement chip test pin TEST2 (UART RX pin) 14 to calibrate the voltage and current ADC error Δ constant value

[0118] Write the calibration register of the voltage and current ADC error of the metering chip 204, and synchronously write the calibration Δ constant value of the voltage and current ADC error to Efuse. Then the control module 201 reads the calibration register value of the voltage and current ADC error through the metering chip test pin TEST1 (TX pin of UART) 13, and compares it with the written calibration Δ constant value of the voltage and current ADC error to see if it is consistent. If it is inconsistent, re-initiate the write operation; the control module 201 reads the data content of the storage address of the calibration Δ constant value of the voltage and current ADC error in Efuse, and compares it with the written calibration Δ constant value of the voltage and current ADC error to see if it is consistent. If it is inconsistent, it is considered to be a bad chip. After the control module 201 compares the calibration register value of the voltage and current ADC error and the calibration Δ constant value of the voltage and current ADC error in Efuse and finds that they are correct, the control module 201 calculates the error based on the current signal and voltage signal conversion value reported by the metering chip 204 after the voltage and current ADC calibration and compares it with the current signal and voltage signal output by the set DC source 202. If the error is ≤±1%, it is determined that the error calibration is qualified and the chip is good, otherwise it is determined that the error calibration fails and the chip is bad.

[0119] Embodiment 3:

[0120] like Figure 6 As shown, the present invention also proposes a calibration method, which is as follows:

[0121] Step 1: The control module controls the opening of the DC signal source

[0122] Step 2: Apply the accurate U / I signal output by the DC signal source to the metering chip, where the voltage signal is input to the metering chip through the electrical sampling circuit, and the current signal is directly input to the metering chip.

[0123] Step 3: The control module writes the compensation value of the temperature drift compensation module into the metering chip.

[0124] Step 4: The control module receives the metering data before the metering chip is calibrated.

[0125] Step 5: The control module determines whether the U\I error is within the calibrable range based on the measurement data reported by the measurement chip.

[0126] Step 6: If the U\I error is within the calibrable range, the control module sends the U\I calibration parameters to the metering chip; if the U\I error is not within the calibrable range, it is judged as a defective product.

[0127] Step 7, the control module receives the metering data reported by the metering chip after calibration, and determines whether the U\I error is within the standard range;

[0128] Step 8: If the U\I error is within the standard range, the calibration error is completed; if the U\I error is not within the standard range, it is judged as a defective product.

[0129] In summary, the present invention has the following technical features:

[0130] 1. The chip integrates current sampling resistors and current sampling circuits to simplify traditional current sampling circuits and reduce costs.

[0131] 2. Aiming at the temperature rise of the built-in current sampling resistor, a high-performance temperature measurement and temperature drift compensation circuit is designed to achieve temperature drift compensation of the sampling resistor and realize over-temperature alarm.

[0132] 3. Use Efuse technology to store chip operating parameters and error calibration parameters inside the chip

[0133] 4. When the voltage passes through zero, the metering data is pushed actively. The single bus realizes data communication and the output of zero-crossing signals, simplifies the communication circuit, and users only need to complete the protocol docking when using it.

[0134] 5. Using a DC signal source as the signal source for chip-level error calibration greatly reduces the requirements for the error calibration standard signal source and improves calibration efficiency.

[0135] 6. Chip-level error calibration, user-level error calibration-free, convenient for users to use and improve user product production efficiency.

[0136] In a specific implementation, the present application provides a computer storage medium and a corresponding data processing unit, wherein the computer storage medium can store a computer program, and when the computer program is executed by the data processing unit, the invention content of a chip system for realizing user-level calibration-free electric energy metering and its calibration method provided by the present invention and some or all steps in each embodiment can be run. The storage medium can be a disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM), etc.

[0137] Those skilled in the art can clearly understand that the technical solutions in the embodiments of the present invention can be implemented by means of computer programs and their corresponding general hardware platforms. Based on such an understanding, the technical solutions in the embodiments of the present invention can be essentially or partly contributed to the prior art in the form of computer programs, i.e., software products, which can be stored in a storage medium and include several instructions for enabling a device including a data processing unit (which can be a personal computer, a server, a single-chip microcomputer, an MCU or a network device, etc.) to execute the methods described in various embodiments of the present invention or certain parts of the embodiments.

[0138] The present invention provides a chip system for realizing user-level calibration-free electric energy metering and a method for calibrating the same. There are many methods and approaches to realize the technical solution. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention. All components not specified in this embodiment can be implemented by existing technologies.

Claims

1. A chip system for realizing user-level calibration-free electric energy metering, characterized in that: include: A current sampling module (101), a temperature measurement and temperature drift compensation module (102), a storage module (103) and a communication module (104) are arranged in the chip; wherein: The current sampling module (101) is used to sample the input current; The temperature measurement and temperature drift compensation module (102) is used to perform temperature drift compensation on the current sampling module (101); The storage module (103) is used to store the chip calibration parameters at the time of leaving the factory; The communication module (104) is used for communication between the chip and external equipment.

2. A chip system for realizing user-level calibration-free electric energy metering according to claim 1, characterized in that: The current sampling module (101) is a sampling resistor implemented using a chip frame base island.

3. A chip system for realizing user-level calibration-free electric energy metering according to claim 1, characterized in that: The performing temperature drift compensation on the current sampling module (101) comprises: Step a1, testing the temperature rise characteristics of the current sampling resistor in the current sampling module (101), that is, testing the resistance of the current sampling resistor within a preset temperature range, and obtaining a fitting temperature drift formula as follows: R (T) =R0[1+(T-T0)×K] Among them, R (T) Indicates the resistance of the current sampling resistor at the current temperature, R0 indicates the resistance of the current sampling resistor at normal temperature, T indicates the current temperature, T0 indicates the typical temperature, and K indicates the ratio of the resistance change rate of the current sampling resistor to the temperature, which is determined by the material properties; Step a2: according to the resistance value R of the current sampling resistor at the current temperature (T) , calculate the exact current value as follows: Among them, V (T) is the voltage value acquired by the current chip, and I is the precise current value; Step a3: calibrate the current value currently measured according to the precise current value I.

4. A chip system for realizing user-level calibration-free electric energy metering according to claim 1, characterized in that: The storage module (103) is an Efuse storage module.

5. A chip system for realizing user-level calibration-free electric energy metering according to claim 4, characterized in that: The storage module (103) stores the chip calibration parameters at the time of leaving the factory, including: Step b1, turning on and adjusting the signal source for calibration, measuring the current and voltage outputted by the signal source as standard values ​​for current and voltage calibration; Step b2, using the electric energy metering chip to measure the current and voltage of the power supply to obtain current and voltage measurement values; Step b3, calculating the current and voltage errors according to the current and voltage calibration values ​​and the current and voltage measurement values; Step b4, storing the calibration value of the current and voltage errors in the storage module (103) for calibrating the electric energy metering chip.

6. A chip system for realizing user-level calibration-free electric energy metering according to claim 5, characterized in that: The signal source described in step b1 is a DC signal power supply.

7. A chip system for realizing user-level calibration-free electric energy metering according to claim 1, characterized in that: The communication module (104) is a UART module.

8. A chip system for realizing user-level calibration-free electric energy metering according to claim 7, characterized in that: The communication module (104) initiates the push of metering data when the voltage passes through zero point, specifically as follows: Whether the voltage signal passes through zero is detected according to the signal waveform of the voltage measurement channel in the electric energy metering chip, and if it is detected that the voltage signal passes through zero, metering data push is initiated through the communication module (104).

9. A chip system for realizing user-level calibration-free electric energy metering according to claim 8, characterized in that: The sampling resistor is 0.1mΩ~5mΩ.

10. A calibration method for a chip system for realizing user-level calibration-free electric energy metering, characterized in that: Calibration using any chip described in claims 1 to 9 comprises the following steps: Step 1, turning on a DC signal source for calibrating the metering chip; Step 2, applying accurate voltage and current signals output by a DC signal source to the metering chip, wherein the voltage signal is input to the metering chip through an electrical sampling circuit, and the current signal is directly input to the metering chip; Step 3: Use the temperature measurement and temperature drift compensation module to perform temperature drift compensation on the metering chip and write the compensation value; Step 4, receiving the measurement data before the measurement chip is calibrated; Step 5: judging whether the voltage and current errors are within the calibrable range according to the measurement data before calibration; Step 6: If the voltage and current errors are within the calibrable range, the voltage and current calibration parameters are calculated and stored; otherwise, the metering chip is judged as a defective product; Step 7, calibrating the metering chip using the voltage and current calibration parameters, and judging whether the voltage and current errors after calibration are within the standard range according to the calibrated metering data; Step 8: If the voltage and current errors are within the standard range, the calibration is completed; otherwise, the metering chip is judged as a defective product.

Images