Direct-current dynamic electric energy standard meter, electric energy metering method thereof and medium

Abstract

The invention discloses a direct-current dynamic electric energy standard meter and a metering method with the direct-current dynamic electric energy standard meter, and the direct-current dynamic electric energy standard meter has the advantages of being high in anti-interference capability, small in equivalent inductive reactance, high in reliability and the like through zero offset correction, precise voltage and current correction, low-leakage isolation, broadband high-precision sampling, high-precision electric energy metering and the like. The distributed capacitance is small, and the temperature drift is small; meanwhile, voltage input adopts shielding type wire connection, distributed capacitance is reduced, and the leakage influence is reduced; a broadband high-precision amplifier is adopted for ripples, an LT1028 operational amplifier of ADI is adopted as the amplifier, and the broadband high-precision amplifier has the advantages of being high in bandwidth and slew rate and is suitable for broadband high-precision amplification within 2.4 KHz; the gain converter performs gain conversion on an input signal, thereby realizing range switching and meeting the requirement of wide-range testing.

Description

Technical Field

[0001] The present invention relates to the technical field of electric energy metering, and in particular to a direct current dynamic electric energy standard meter and an electric energy metering method thereof. Background Art

[0002] In the process of building new power systems, new energy electric vehicles, photovoltaic power generation, energy storage and grid-connected DC power distribution and utilization are booming. The high proportion of new energy and high proportion of power electronic equipment access in new power systems have led to an increase in the fluctuation range and randomness of DC signal voltage and current, a higher proportion of ripple components, an increase in the fluctuation range of ripple amplitude and frequency, and an increase in the randomness of fluctuations, and new types and forms of signals are constantly emerging.

[0003] Dynamic characteristics such as the random time-varying nature of the pseudo-periodic ripple component in the DC signal and the random speed-varying nature of the DC load affect the accuracy of DC power measurement. The JJF 1779-2019 "Outline for Type Evaluation of Electronic DC Power Meters" stipulates that DC power meters only measure DC components and do not measure ripple components.

[0004] Although the accuracy of existing standard DC energy meters can reach 0.01 level, they only consider the precise measurement of DC components under steady-state conditions, and do not consider the influence of ripple power and the precise measurement method of ripple. Therefore, the traditional standard DC energy meter and its DC energy measurement method can no longer meet the needs of accurate measurement and fair trading of DC energy in new power systems. It is urgent to study the precise sampling of random fast-changing DC components and ripple components, high-precision signal amplification, zero offset correction and other DC dynamic energy precise measurement technologies, and develop DC standard energy meters that take into account dynamic characteristics to improve the accuracy of DC energy measurement. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a DC dynamic electric energy standard meter, which adopts zero offset correction, precision voltage and current correction, low leakage isolation, wide-band high-precision sampling, high-precision electric energy measurement and other methods to achieve accurate measurement of DC dynamic electric energy.

[0006] The present invention also provides an electric energy metering method having the above-mentioned DC dynamic electric energy standard meter.

[0007] The DC dynamic electric energy standard meter according to the first aspect of the present invention is characterized by comprising:

[0008] The front-end signal processing module includes a zero offset correction module, a voltage conversion module and a current module; the high voltage signal is input into the zero offset correction module, and after passing through the voltage conversion module and the current module, it is converted into a sampling current signal and a sampling voltage signal, which are output to the AD sampling module respectively;

[0009] The AD sampling module includes a voltage sampling module, a current sampling module and a digital isolation module; the sampled voltage signal is input into the voltage sampling module, the sampled current signal is input into the current sampling module, and then enters the digital isolation module;

[0010] An electric energy metering module, comprising a data processing module, an electric energy pulse output module and an electric energy error calculation module; the electric energy metering module can obtain a sampled voltage signal and a sampled current signal from the digital isolation module, and perform broadband dynamic DC component metering, ripple component metering and total electric energy metering via the data processing module to achieve electric energy statistics;

[0011] The human-computer interaction module includes an interaction control module and an interaction communication module; it is connected to the data processing module via a serial port or a network port to transmit the data collected by the electric energy metering module.

[0012] The DC dynamic electric energy standard meter according to the embodiment of the present invention has at least the following beneficial effects:

[0013] The DC dynamic electric energy standard meter provided by the present invention applies methods such as zero offset correction, precision voltage and current correction, low leakage isolation, broadband high-precision sampling, and high-precision electric energy measurement, and has the characteristics of strong anti-interference ability, small equivalent inductance, small distributed capacitance, and small temperature drift; at the same time, a shielded wire connection is used for voltage input to reduce distributed capacitance and reduce leakage influence; a broadband high-precision amplifier is used for ripple, and ADI's LT1028 operational amplifier is used as the amplifier, which has the characteristics of high bandwidth and high slew rate and is suitable for broadband high-precision amplification within 2.4KHz; the input signal is gain-converted by a gain converter to achieve range switching and meet the requirements of wide-range testing.

[0014] According to some embodiments of the present invention, the zero offset correction module includes an effective value offset correction element, a phase correction element and a gain correction element, and adopts an adaptive dynamic adjustment method to set multiple calibration points to cover the main voltage and current calibration points within the working range of the electric energy meter, and independently calculates each calibration point to refresh the calibration value in real time, and adopts forward-reverse excitation measurement and switch commutation measurement.

[0015] According to some embodiments of the present invention, the voltage conversion module voltage divider resistor includes a high-end bridge arm resistor, a low-end bridge arm resistor, a shielding line, a low-impedance analog switch and a wide-band amplifier.

[0016] According to some embodiments of the present invention, the high-end bridge arm resistor and the low-end bridge arm resistor are connected in series to divide the voltage, so as to convert the input high voltage into the low voltage that needs to be sampled; the high-end bridge arm resistor and the low-end bridge arm resistor are connected by a shielded connecting wire, and the input signal is divided into two parts for measurement through a low-impedance analog switch, and the low-frequency part adopts a low-frequency high-precision amplifier based on junction field effect transistor (JFET) input to achieve low-frequency and high-precision measurement; the high-frequency part adopts a wide-band high-precision amplifier to achieve wide-band and high-precision measurement within 2.4KHz.

[0017] According to some embodiments of the present invention, the current conversion module includes a large current conversion module and a small current conversion module;

[0018] The large current conversion module includes an active zero flux sensor, a current and voltage I / V conversion module and a gain conversion module;

[0019] The small current conversion module mainly includes a platinum resistor, a current-voltage I / V conversion module, a gain amplifier and an operational amplifier.

[0020] According to some embodiments of the present invention, the active zero-flux sensor includes a reference voltage of a current-type DAC, a DSP processor, a frequency multiplication circuit, a programmable filter, a phase-sensitive demodulator, a PI control circuit, a power amplifier, an iron core, a programmable compensation signal tracker, a programmable timer, and an excitation source amplification drive module.

[0021] According to some embodiments of the present invention, the excitation source amplification and driving module includes a common-phase amplifier and an inverting amplifier, a two-ended driving output, and generates a magnetic field on the iron core of the fluxgate current sensor through an excitation winding according to the control output voltage square wave signal of the DSP processor.

[0022] According to some embodiments of the present invention, the programmable compensation signal tracker is in a bidirectional adjustment mode, and the compensation voltage output is controlled by a digital quantity. The compensation voltage is used to perform factory zero calibration on the fluxgate sensor through a compensation coil.

[0023] According to some embodiments of the present invention, the programmable filter is a second-order filter having high-pass and low-pass bandpass outputs, and the programmable filter also has two DA loops for configuring different center frequency filters according to different excitation frequencies.

[0024] According to some embodiments of the present invention, the phase-sensitive demodulator includes a voltage tracking module, an inverter and a multiplexing module.

[0025] According to some embodiments of the present invention, the small current conversion module platinum resistor converts the input current into a voltage that can be sampled and measured by AD, and completes the measurement of the current by measuring the voltage.

[0026] According to some embodiments of the present invention, the frequency division sampling module includes a low-frequency voltage / current sampling module and a wide-frequency voltage / current sampling module; wherein

[0027] The low-frequency voltage / current sampling module includes ADI's AD7172 converter, analog / digital signal conditioning module, integrated buffer, digital filter and input / output controller, and adopts synchronous sampling technology to sample signals of multiple channels at the same time point to achieve low-frequency voltage / current sampling;

[0028] The broadband voltage / current sampling module includes a sigma-delta 24Bit ADS1278 converter, which integrates multiple independent high-order chopper-stabilized modulators and FIR digital filters, and supports four working modes: high speed, high precision, low power consumption, and low speed.

[0029] According to some embodiments of the present invention, the analog / digital signal conditioning module supports users to individually configure each analog input channel in use through SPI; the integrated buffer is an integrated module of the analog input terminal and the external reference voltage input terminal, providing a high-impedance input; the digital filter allows synchronous 50Hz / 60Hz suppression at an output data rate of 27.27SPS; the input / output controller can control an external multiplexer and synchronize to the ADC conversion timing.

[0030] According to some embodiments of the present invention, the digital isolation module is configured between the AD sampling module and the data processing module, and includes a high-speed CMOS chip, a single-chip air-core transformer, a level conversion module and an isolation channel configuration module.

[0031] According to some embodiments of the present invention, the digital isolation module is based on the isolated synchronous sampling technology of ADS1278, has a synchronous input control pin, and is controlled by an external clock signal to achieve synchronous sampling between two ADS1278 chips and isolated synchronous sampling of dynamic DC input voltage and current signals.

[0032] According to some embodiments of the present invention, the processing module is a dual-core DSP processor, and is expanded with 128M of DDR synchronous memory and 32M of asynchronous access Flash.

[0033] A DC dynamic electric energy metering method according to a second aspect of the present invention is applied to the above-mentioned DC dynamic electric energy standard meter, comprising:

[0034] Convert the input high voltage into the low voltage that needs to be sampled;

[0035] The logic timing of the voltage sampling chip and the current sampling chip is controlled by an external clock signal. Based on the frequency adaptive quasi-synchronous algorithm, the voltage and current signals of the dynamic DC input are isolated and synchronously sampled through a digital isolator.

[0036] When calculating the cumulative total electric energy of the DC component and the ripple component, the signal after multiplying the voltage and current signals can obtain the full-wave power through an adaptive multi-order wide-band quasi-synchronous algorithm, and the full-wave electric energy can be obtained after integration operation; the average voltage and average current values ​​are obtained through an adaptive multi-order wide-band quasi-synchronous algorithm, and the active power of the DC component can be obtained by multiplying the average voltage and the average current values, and the DC electric energy can be obtained after integration operation; the active power obtained by subtracting the DC component electric energy from the accumulated electric energy full-wave power is then integrated to obtain the ripple electric energy.

[0037] According to some embodiments of the present invention, before obtaining the sampled voltage, the method further includes:

[0038] Adaptive dynamic adjustment is adopted to set multiple calibration points to cover the main voltage and current calibration points within the working range of the electric energy meter, and each calibration point is independently calculated to refresh the calibration value in real time. The influence of system thermoelectric potential is eliminated through forward-reverse excitation measurement and switch commutation measurement.

[0039] According to some embodiments of the present invention, the step of converting the input high voltage into a low voltage to be sampled specifically includes:

[0040] The input high voltage is converted into the low voltage that needs to be sampled by connecting the high-end bridge arm resistor and the low-end bridge arm resistor in series to divide the voltage.

[0041] According to a third aspect of the present invention, a computer-readable storage medium is provided, wherein the medium stores computer-executable instructions, and the computer-executable instructions are used to execute the above-mentioned direct current dynamic electric energy metering method.

[0042] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0044] Figure 1 A schematic diagram of the logical architecture of a DC dynamic electric energy standard meter according to an embodiment of the present invention;

[0045] Figure 2 A schematic diagram of the structure of a voltage conversion module in a DC dynamic electric energy standard meter according to an embodiment of the present invention;

[0046] Figure 3 It is a structural schematic diagram of an active zero flux sensor in a DC dynamic electric energy standard meter according to an embodiment of the present invention;

[0047] Figure 4 A schematic diagram of the steps of a DC dynamic electric energy measurement method provided by an embodiment of the present invention;

[0048] Figure 5 The present invention is a flowchart of a wide-band high-precision synchronous isolation sampling process in a DC dynamic electric energy metering method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0049] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0050] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0051] In the description of the present invention, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed" etc. are understood as not including the number itself, and "above", "below", "within" etc. are understood as including the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0052] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0053] Embodiment 1

[0054] In view of the random time-varying dynamic characteristics of the current DC load and the problems existing in the dynamic measurement process of the existing standard DC electric energy meter, the embodiment of the present application provides a DC dynamic electric energy standard meter, such as Figure 1 As shown, including:

[0055] The front-end signal processing module includes a zero offset correction module, a voltage conversion module and a current module; the high voltage signal is input into the zero offset correction module, and after passing through the voltage conversion module and the current module, it is converted into a sampling current signal and a sampling voltage signal, which are output to the AD sampling module respectively;

[0056] The AD sampling module includes a voltage sampling module, a current sampling module and a digital isolation module; the sampled voltage signal is input into the voltage sampling module, the sampled current signal is input into the current sampling module, and then enters the digital isolation module;

[0057] An electric energy metering module, comprising a data processing module, an electric energy pulse output module and an electric energy error calculation module; the electric energy metering module can obtain a sampled voltage signal and a sampled current signal from the digital isolation module, and perform broadband dynamic DC component metering, ripple component metering and total electric energy metering via the data processing module to achieve electric energy statistics;

[0058] The human-computer interaction module includes an interaction control module and an interaction communication module; it is connected to the data processing module via a serial port or a network port to transmit the data collected by the electric energy metering module.

[0059] Among them, the zero offset correction module mainly includes effective value offset correction, phase correction and gain correction modules. It adopts an adaptive dynamic adjustment method to set multiple calibration points to cover the main voltage and current calibration points within the working range of the electric energy meter, and independently calculates each calibration point to refresh the calibration value in real time, and eliminates the influence of system thermoelectric potential through forward-reverse excitation measurement and switch commutation measurement.

[0060] Furthermore, the voltage conversion module mainly includes voltage-dividing resistors, which include high-end bridge arm resistors, low-end bridge arm resistors, shielding wires, low-impedance analog switches and wide-band amplifiers.

[0061] The input high voltage is converted to the low voltage that needs to be sampled by connecting the high-end bridge arm resistor and the low-end bridge arm resistor in series. Both the high-end bridge arm resistor and the low-end bridge arm resistor are integrated voltage divider resistors. Shielded connecting wires are used for connection. Through low-impedance analog switches, the input signal is divided into two parts for measurement. The low-frequency part uses a low-frequency amplifier based on JFET input to achieve low-frequency measurement; the high-frequency part uses a wide-band amplifier to achieve wide-band high-precision measurement within 2.4KHz. The voltage conversion module structure is as follows: Figure 2 shown.

[0062] The current conversion module mainly includes a large current conversion module and a small current conversion module. Among them:

[0063] The large current conversion module mainly includes an active zero flux sensor, a current and voltage I / V conversion module, and a gain conversion module. The large current is first converted into a small current through a zero flux transformer, and then converted into a voltage signal with the small current I / V conversion. The gain converter realizes fast range switching and converts it into a voltage signal suitable for ADC sampling to achieve the measurement of large current. The large current conversion module uses dynamic configuration technology to achieve virtual zero resistance of input impedance, and changes the primary side of the zero flux transformer by the equal ampere-turn method to achieve range switching, which can achieve the purpose of high-accuracy measurement of large current with a bandwidth of 100kHz.

[0064] Furthermore, the active zero flux sensor is mainly composed of a reference voltage of a current-type DAC, a DSP (BF533) processor, a frequency multiplication circuit, a programmable filter, a phase-sensitive demodulator, a PI control circuit, a power amplifier, an iron core, a programmable compensation signal tracker, a programmable timer, an excitation source amplification drive module, etc. Figure 3 shown.

[0065] Furthermore, based on the continuous input characteristics of the reference voltage of the current-type DAC, the reference voltage is used as the tracking voltage input to achieve continuous digital adjustment. A unipolar-to-bipolar circuit is used at the output of the DAC to adjust the positive and negative drift of the core, completing the programmable compensation signal tracking of bidirectional adjustment. The excitation current frequency is dynamically adjusted through a programmable timer, and the center frequency of the filter is dynamically adjusted through a DA converter combined with a programmable filter, thereby achieving the adjustment of the fluxgate to the core excitation frequency under different application requirements to achieve the best match.

[0066] Furthermore, the excitation source is mainly used to generate an alternating magnetic field and dynamically adjust the frequency of the magnetic field to adapt to different measurement conditions and requirements.

[0067] Furthermore, the excitation source amplification driving module includes a common-phase amplifier and an inverting amplifier, and a double-ended driving output. According to the control output voltage square wave signal of the processor, a magnetic field is generated on the core of the fluxgate current sensor through the excitation winding.

[0068] Furthermore, the programmable compensation signal tracker is in a bidirectional adjustment mode, which controls the compensation voltage output through digital quantity. The compensation voltage then passes through the compensation coil to achieve factory zero-position calibration of the fluxgate sensor, turning the process consistency requirement for the core into a calibration parameter stored in the DSP, greatly reducing the requirements for process consistency of the two fluxgate cores.

[0069] Furthermore, the programmable filter is a second-order filter having both high-pass and low-pass bandpass outputs. The filter is added with two DA loops for configuring different center frequency filters according to different excitation frequencies.

[0070] Furthermore, the phase-sensitive demodulator mainly includes a voltage tracking module, an inverter and a multiplexer module, and is mainly used to realize full-wave demodulation of the input signal.

[0071] Furthermore, the frequency adaptation module realizes dynamic adjustment of the exciting current frequency through a programmable timer to adapt to different measurement conditions and improve measurement performance.

[0072] The small current conversion module mainly includes a platinum resistor, a current-voltage I / V conversion module, a gain amplifier and an operational amplifier. The input current is converted into a voltage that can be sampled and measured by AD through a platinum resistor, and the current is finally measured by measuring the voltage. When converting current to voltage (I / V), the resistor is first connected in series to the external input current signal, and the voltage signal on the resistor is converted by the amplifier, and finally a voltage value suitable for AD sampling is obtained.

[0073] The frequency division sampling module mainly includes a low-frequency voltage / current sampling module and a wide-frequency voltage / current sampling module.

[0074] in:

[0075] The low-frequency voltage / current sampling module is mainly composed of ADI's AD7172 converter, analog / digital signal conditioning module, integrated buffer, digital filter and input / output (GPIO) controller. It uses synchronous sampling technology to sample signals of multiple channels at the same time point to achieve accurate sampling of low-frequency voltage / current.

[0076] Furthermore, the analog / digital signal conditioning module allows the user to individually configure each analog input channel in use via SPI.

[0077] Furthermore, the integrated buffer is an integrated module of the analog input terminal and the external reference voltage input terminal, and can provide a high impedance input that is easy to drive.

[0078] Furthermore, the digital filter allows for simultaneous 50Hz / 60Hz rejection at a 27.27SPS output data rate, and the user can switch between different filter options based on the needs of each channel in the application.

[0079] Furthermore, an input / output (GPIO) controller can control an external multiplexer and synchronize to the ADC conversion timing.

[0080] Furthermore, the broadband voltage sampling module mainly includes a sigma-delta 24Bit ADS1278 converter, which integrates multiple independent high-order chopper-stabilized modulators and FIR digital filters, can realize 8-channel synchronous sampling, support four working modes of high speed, high precision, low power consumption and low speed, and realize accurate sampling of broadband voltage / current.

[0081] The digital isolation module is configured between the AD sampling module and the data processing module. It is mainly composed of a high-speed CMOS chip, a single-chip air-core transformer, a level conversion module, and an isolation channel configuration module. It uses magnetic coupling technology to isolate the voltage and current measurements from each other without affecting the sampling synchronization between the voltage and current.

[0082] The digital isolation module is based on the isolated synchronous sampling technology of ADS1278 and has a synchronous input control pin. It can be controlled by an external clock signal to achieve synchronous sampling between two ADS1278s and isolated synchronous sampling of voltage and current signals of dynamic DC input.

[0083] The data processing module is a dual-core DSP processor, and has expanded 128M DDR synchronous memory and 32M asynchronous access Flash, providing powerful signal processing capabilities for the DC dynamic standard meter. The data processing module reads the voltage and current sampling chip data at high speed through its SPI interface for high-speed processing.

[0084] The electric energy error calculation module mainly includes the DC electric energy calculation module, the ripple electric energy calculation module and the total electric energy calculation module. The frequency measurement and signal separation technology of DC and ripple signals under dynamic DC and the state adaptive electric energy precision measurement technology are used to realize the broadband dynamic DC component measurement, ripple component measurement and total electric energy measurement.

[0085] The DSP processor is connected to the human-computer interaction module, communicates with the human-computer interaction module through the serial port or network port, receives the parameter setting data of the human-computer interaction module, and transmits the calculated measurement data, such as the amplitude of voltage and current, power and electric energy, electric energy error, pulse constant and other data to the human-computer interaction module to complete the display control of human-computer interaction.

[0086] The interactive control module mainly includes a touch screen, uses Windows XP system, and uses Labview software for instrument control design.

[0087] The human-computer interaction communication module mainly includes network port, serial port and USB port communication interface.

[0088] Embodiment 2

[0089] The DC dynamic electric energy standard meter provided in the first embodiment realizes the DC dynamic electric energy measurement. The DC dynamic electric energy measurement method specifically includes the following steps:

[0090] Step S1: Zero offset correction: When calibrating DC power, firstly perform zero offset correction on the dynamic DC standard meter.

[0091] Adaptive dynamic adjustment is adopted to set multiple calibration points to cover the main voltage and current calibration points within the working range of the electric energy meter, and each calibration point is independently calculated to refresh the calibration value in real time. The influence of system thermoelectric potential is eliminated through forward-reverse excitation measurement and switch commutation measurement.

[0092] Step S2: Precise voltage and current changes.

[0093] Precision voltage changes convert the input high voltage into the low voltage that needs to be sampled by connecting the high-end bridge arm resistor and the low-end bridge arm resistor in series. Both the high-end bridge arm resistor and the low-end bridge arm resistor are integrated precision voltage divider resistors. Shielded connecting wires are used for connection, and the input signal is divided into two parts for measurement through a low-impedance analog switch. The low-frequency part uses a low-frequency high-precision amplifier based on JFET input to achieve low-frequency and high-precision measurement; the high-frequency part uses a wide-band high-precision amplifier to achieve wide-band and high-precision measurement within 2.4KHz

[0094] The precision current conversion module mainly includes two types of conversion methods: large current conversion and small current conversion.

[0095] The large current conversion process is: firstly, it is converted into a small current through a zero flux transformer, and then converted into a voltage signal with the small current I / V conversion, and then quickly switched between ranges through a gain converter, and then converted into a voltage signal suitable for ADC sampling to achieve the measurement of large current. The large current conversion module uses dynamic configuration technology to achieve virtual zero resistance of input impedance, and changes the primary side of the zero flux transformer by the equal ampere-turn method to achieve range switching, which can achieve the purpose of high-accuracy measurement of large current with a bandwidth of 100kHz.

[0096] The small current conversion process is: through the precision platinum resistor, the input current is converted into a voltage that can be sampled and measured by AD, and finally the current measurement is completed by measuring the voltage. When converting current to voltage (I / V), the precision resistor is first connected in series to the external input current signal, and the voltage signal on the resistor is converted by the amplifier, and finally a voltage value suitable for AD sampling is obtained.

[0097] Step S3: broadband high-precision synchronous isolation sampling.

[0098] The broadband high-precision synchronous isolation sampling process is as follows: using the isolated synchronous sampling technology of ADS1278, controlling the logic timing of the voltage sampling chip and the current sampling chip through an external clock signal, and based on the frequency adaptive quasi-synchronous algorithm, realizing isolated synchronous sampling of the voltage and current signals of the dynamic DC input through a digital isolator, such as Figure 5 shown.

[0099] Step S4: high-precision electric energy measurement.

[0100] High-precision electric energy measurement methods mainly include total electric energy, DC electric energy and ripple electric energy. Specifically include:

[0101] Step S41, when calculating the cumulative total electric energy of the DC component and the ripple component, the signal after the voltage and current signals are multiplied can obtain the full-wave power through an adaptive multi-order wide-band quasi-synchronous algorithm, and the full-wave electric energy can be obtained after integration operation.

[0102] Step S42: For the DC component electric energy, the average voltage and average current values ​​are obtained through an adaptive multi-order wideband quasi-synchronous algorithm. The active power of the DC component can be obtained by multiplying the average voltage and the average current values. After integration operation, the DC electric energy is obtained.

[0103] Step S43: For the electric energy of the ripple component, the power can be obtained by subtracting the active power obtained by the accumulated electric energy full-wave power from the DC component electric energy, and then the ripple electric energy is obtained after integration operation.

[0104] Embodiment 3

[0105] Another embodiment of the present invention provides a computer-readable storage medium storing computer-executable instructions for executing the above-mentioned Figure 4 The DC dynamic energy measurement method shown.

[0106] The embodiment of the present application uses the above-mentioned DC dynamic electric energy metering method stored in the medium, based on low-frequency quasi-synchronous algorithm technology, and uses a new algorithm for processing to eliminate synchronization errors and achieve an accuracy close to "ideal synchronous sampling".

[0107] The device embodiments described above are only illustrative, and the units described as separate components may or may not be physically separated, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0108] It will be appreciated by those skilled in the art that all or some of the steps and systems in the disclosed method above may be implemented as software, firmware, hardware and appropriate combinations thereof. Some physical components or all physical components may be implemented as software executed by a processor, such as a central processing unit, a digital signal processor or a microprocessor, or may be implemented as hardware, or may be implemented as an integrated circuit, such as an application specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include a computer storage medium (or a non-transitory medium) and a communication medium (or a temporary medium). As known to those skilled in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tapes, disk storage or other magnetic storage devices, or any other medium that may be used to store desired information and may be accessed by a computer. Furthermore, it is well known to those skilled in the art that communication media typically embodies computer readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

[0109] The above is a specific description of the preferred implementation of the present application, but the present application is not limited to the above-mentioned implementation mode. Technical personnel familiar with the field can also make various equivalent deformations or substitutions without violating the spirit of the present application. These equivalent deformations or substitutions are all included in the scope defined by the claims of the present application.

Claims

1. A DC dynamic electric energy standard meter, characterized in that: include: The front-end signal processing module includes a zero offset correction module, a voltage conversion module, and a current module; the high voltage signal is input into the zero offset correction module, and after passing through the voltage conversion module and the current module, it is converted into a sampling current signal and a sampling voltage signal, which are output to the AD sampling module respectively; AD sampling module, including voltage sampling module, current sampling module and digital isolation module; the sampled voltage signal is input into the voltage sampling module, the sampled current signal is input into the current sampling module, and then enters the digital isolation module; An electric energy metering module, comprising a data processing module, an electric energy pulse output module, and an electric energy error calculation module; the electric energy metering module can obtain a sampled voltage signal and a sampled current signal from the digital isolation module, and perform broadband dynamic DC component measurement, ripple component measurement, and total electric energy measurement via the data processing module to achieve electric energy statistics; Human-computer interaction module, including interactive control module and interactive communication module; The data collected by the electric energy metering module is transmitted by connecting to the data processing module via a serial port or a network port.

2. The DC dynamic electric energy standard meter according to claim 1, characterized in that: The zero offset correction module includes an effective value offset correction element, a phase correction element and a gain correction element. It adopts an adaptive dynamic adjustment method, sets multiple calibration points to cover the main voltage and current calibration points within the working range of the electric energy meter, and independently calculates each calibration point to refresh the calibration value in real time. It also adopts forward-reverse excitation measurement and switch commutation measurement.

3. The DC dynamic electric energy standard meter according to claim 1, characterized in that: The voltage conversion module voltage divider resistor includes a high-end bridge arm resistor, a low-end bridge arm resistor, a shielding line, a low-impedance analog switch and a broadband amplifier.

4. The DC dynamic electric energy standard meter according to claim 3, characterized in that: The high-end bridge arm resistor and the low-end bridge arm resistor are connected in series to divide the voltage, thereby converting the input high voltage into the low voltage that needs to be sampled; the high-end bridge arm resistor and the low-end bridge arm resistor are connected by a shielded connecting wire, and the input signal is divided into two parts for measurement through a low-impedance analog switch. The low-frequency part adopts a low-frequency amplifier based on junction field-effect transistor input to achieve low-frequency measurement; the high-frequency part adopts a wide-band amplifier to achieve wide-band high-precision measurement within 2.4KHz.

5. The DC dynamic electric energy standard meter according to claim 1, characterized in that: The current conversion module includes a large current conversion module and a small current conversion module; The large current conversion module includes an active zero-flux sensor, a current-voltage I / V conversion module and a gain conversion module; The small current conversion module mainly includes a platinum resistor, a current-voltage I / V conversion module, a gain amplifier and an operational amplifier.

6. The DC dynamic electric energy standard meter according to claim 5, characterized in that: The active zero-flux sensor includes a reference voltage of a current-type DAC, a DSP processor, a frequency multiplication circuit, a programmable filter, a phase-sensitive demodulator, a PI control circuit, a power amplifier, an iron core, a programmable compensation signal tracker, a programmable timer, and an excitation source amplification and driving module.

7. The DC dynamic electric energy standard meter according to claim 6, characterized in that: The excitation source amplification and driving module includes a common-phase amplifier and an inverting amplifier, and a double-ended driving output. According to the control output voltage square wave signal of the DSP processor, a magnetic field is generated on the iron core of the fluxgate current sensor through the excitation winding.

8. The DC dynamic electric energy standard meter according to claim 6, characterized in that: The programmable compensation signal tracker is in a bidirectional adjustment mode, and the compensation voltage output is controlled by digital quantity. The compensation voltage is used to perform factory zero calibration on the fluxgate sensor through the compensation coil.

9. The DC dynamic electric energy standard meter according to claim 6, characterized in that: The programmable filter is a second-order filter with high-pass and low-pass bandpass outputs. The programmable filter also has two DA loops for configuring different center frequency filters according to different excitation frequencies.

10. The DC dynamic electric energy standard meter according to claim 6, characterized in that: The phase-sensitive demodulator includes a voltage tracking module, an inverter and a multiplexing module.

11. The DC dynamic electric energy standard meter according to claim 5, characterized in that: The small current conversion module platinum resistor converts the input current into a voltage that can be sampled and measured by AD, and completes the current measurement through the voltage measurement.

12. The DC dynamic electric energy standard meter according to claim 1, characterized in that: The frequency division sampling module includes a low-frequency voltage / current sampling module and a wide-frequency voltage / current sampling module; wherein The low-frequency voltage / current sampling module includes ADI's AD7172 converter, analog / digital signal conditioning module, integrated buffer, digital filter and input / output controller. It adopts synchronous sampling technology to sample the signals of multiple channels at the same time point to achieve low-frequency voltage / current sampling. The broadband voltage / current sampling module includes a sigma-delta 24-bit ADS1278 converter, which integrates multiple independent high-order chopper-stabilized modulators and FIR digital filters, and supports four operating modes: high speed, high precision, low power consumption, and low speed.

13. The DC dynamic electric energy standard meter according to claim 12, characterized in that: The analog / digital signal conditioning module allows users to individually configure each analog input channel in use via SPI. The integrated buffer is an integrated module for the analog input and external reference voltage input, providing a high-impedance input. The digital filter allows for synchronous 50Hz / 60Hz rejection at a 27.27SPS output data rate. The input / output controller can control an external multiplexer and synchronize to the ADC conversion timing.

14. The DC dynamic electric energy standard meter according to claim 1, characterized in that: The digital isolation module is configured between the AD sampling module and the data processing module, and includes a high-speed CMOS chip, a single-chip air-core transformer, a level conversion module and an isolation channel configuration module.

15. The DC dynamic electric energy standard meter according to claim 14, characterized in that: The digital isolation module is based on the isolated synchronous sampling technology of ADS1278 and has a synchronous input control pin. It is controlled by an external clock signal to achieve synchronous sampling between two ADS1278 chips and isolated synchronous sampling of voltage and current signals of dynamic DC input.

16. The DC dynamic electric energy standard meter according to claim 1, characterized in that: The processing module is a dual-core DSP processor and has an extended 128M DDR synchronous memory and a 32M asynchronous access Flash.

17. A DC dynamic electric energy metering method, applied to the DC dynamic electric energy standard meter described in any one of claims 1 to 17, comprising: Convert the input high voltage to the low voltage that needs to be sampled; The logic timing of the voltage sampling chip and the current sampling chip is controlled by an external clock signal. Based on the frequency adaptive quasi-synchronous algorithm, the voltage and current signals of the dynamic DC input are isolated and synchronously sampled through a digital isolator. When calculating the cumulative total energy of the DC component and the ripple component, the signal after multiplying the voltage and current signals can be used to obtain the full-wave power through an adaptive multi-order wide-band quasi-synchronous algorithm, and the full-wave energy can be obtained after integration. The average voltage and average current values ​​are obtained through the adaptive multi-order wide-band quasi-synchronous algorithm, and the active power of the DC component can be obtained by multiplying the average voltage and average current values, and the DC energy can be obtained after integration. The active power is obtained by subtracting the DC component energy from the accumulated full-wave power, and then the ripple energy is obtained after integration.

18. The method according to claim 17, characterized in that Before obtaining the sampled voltage, the method further includes: Adaptive dynamic adjustment is adopted to set multiple calibration points to cover the main voltage and current calibration points within the working range of the electricity meter. Each calibration point is independently calculated and the calibration value is refreshed in real time. The influence of system thermoelectric potential is eliminated through forward-reverse excitation measurement and switch commutation measurement.

19. The method according to claim 17, wherein The step of converting the input high voltage into the low voltage to be sampled specifically includes: The input high voltage is converted into the low voltage that needs to be sampled by connecting the high-end bridge arm resistor and the low-end bridge arm resistor in series to divide the voltage.

20. A computer-readable storage medium storing computer-executable instructions, wherein the computer-executable instructions are used to execute the method according to any one of claims 17 to 19.

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