CN113702897A - Anti-harmonic interference three-phase electric energy meter on-site calibration instrument - Google Patents
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Abstract
The invention discloses an anti-harmonic interference three-phase electric energy meter on-site calibration instrument, which comprises: the device comprises a three-phase clamp-on current sensor, a three-phase clamp-on voltage sensor, a signal filtering and amplifying circuit, an A/D converter, a standard meter reference voltage and reference current input interface, a shaping circuit, a standard crystal oscillator, an FPGA frequency multiplication data acquisition unit, a frequency division phase-locked loop, a CPU data processing unit, an LED display output circuit and a power supply unit; the invention adds a frequency division phase-locked loop between the A/D converter and the FPGA frequency multiplication data acquisition unit, utilizes the phase-locked loop to keep the frequency phase of the frequency division phase-locked loop consistent with the input signal of the synchronous acquisition pulse, realizes the self-adaptability and anti-interference of frequency tracking, ensures that the frequency is equal to a certain extent under the condition that the phase difference between the voltage and the current of the measured running electric energy meter and the phase difference between the voltage and the current of a standard meter are constant, utilizes a frequency division feedback loop to perform feedback adjustment on the output, keeps the output digital signal undistorted, and improves the anti-harmonic interference capability.
Description
Technical Field
The invention belongs to the technical field of electric energy meter check meters, and particularly relates to a three-phase electric energy meter on-site check meter capable of resisting harmonic interference.
Background
The electric energy meter in actual operation has defects or faults of different degrees and different types due to problems of operation environment, time, electric energy meter version and the like, for example, problems of internal faults of the electric energy meter, over-tolerance of the electric energy meter, voltage loss of a voltage loop or current loss of a current loop or external faults and the like can affect the metering accuracy of the intelligent electric meter to a certain extent, and therefore certain loss is caused to the conventional electric quantity statistics and accounting. According to the requirements of the existing asset life-cycle management in China, the currently implemented electric energy meter calibration and operation spot inspection regulation mainly comprises laboratory establishment and spot electric energy meter operation spot inspection. The existing laboratory spot check obtains the error characteristics of the electric energy meter by simulating the voltage, the current and the frequency of the electric energy meter under the working environment of a journey and respectively inputting the electric quantity information into a standard electric energy meter and a checked electric energy meter, and the error characteristics are equivalent to off-line check and cannot completely meet the real working environment of the electric energy meter check site, so that the real error characteristics of the electric energy meter are reflected by the on-site on-line check. The on-line calibration is that the metering device operation and maintenance personnel carry the portable electric energy meter calibrator to carry out calibration without power outage on site.
The actual operation environment and conditions of the running electric energy meter are not necessarily the same, the degree of influence of external factors is different, whether the metering accuracy of the electric energy meter can be still ensured under various complex conditions of a large amount of harmonic waves, inter-harmonic waves, spike pulses, attenuated direct current, nonlinear loads connected into a power grid and the like on site exists or not, the obtained experimental data is actually attached through an online checking mode, the error characteristic of the electric energy meter can be truly reflected, and therefore important support is provided for accurate judgment of the metering performance of the electric energy meter. However, the on-site on-line verification has the interference of temperature, humidity, frequency and harmonic waves and is very easy to be interfered by natural conditions such as weather.
Although the portable calibrator has a certain correction coefficient, the correction coefficient is data obtained by simulating in a laboratory under normal power frequency, and the requirements of field work cannot be completely met. And the operation sampling and checking meter is necessary for daily work of a monthly power supply station, so that the research on the anti-harmonic interference check meter has important practical significance.
Disclosure of Invention
The invention overcomes the defects of the prior art, and solves the technical problems that: the three-phase electric energy meter on-site calibration instrument can improve the resistance to harmonic interference.
In order to solve the technical problems, the invention adopts the technical scheme that: an anti-harmonic interference three-phase electric energy meter on-site calibrator, comprising: the device comprises a three-phase clamp-on current sensor, a three-phase clamp-on voltage sensor, a signal filtering and amplifying circuit, an A/D converter, a standard meter reference voltage and reference current input interface, a shaping circuit, a standard crystal oscillator, an FPGA frequency multiplication data acquisition unit, a frequency division phase-locked loop, a CPU data processing unit, an LED display output circuit and a power supply unit;
the input end of the three-phase pincerlike current sensor and the input end of the three-phase pincerlike voltage sensor are respectively connected with the current end and the voltage end of an electric meter, the output end of the three-phase pincerlike current sensor and the output end of the three-phase pincerlike voltage sensor are respectively connected with the input end of a signal filtering and amplifying circuit and the input end of a shaping circuit, the output end of the signal filtering and amplifying circuit, the reference voltage of a standard meter and the input interface of the reference current are respectively connected with the input end of an A/D converter, the output end of the shaping circuit and a standard crystal oscillator are respectively connected with the input end of an FPGA frequency doubling data acquisition unit, the output end of the FPGA frequency doubling data acquisition unit is connected with an LED display output circuit through a CPU data processing unit, the FPGA frequency doubling data acquisition unit is bidirectionally connected with a frequency division phase-locked loop, and the frequency division phase-locked loop is bidirectionally connected with the A/D converter, the power supply unit supplies power to the CPU data processing unit and the peripheral circuit.
Furthermore, the frequency division phase-locked loop comprises a biquad generalized integrator frequency locking loop, a delay signal elimination filter and a moving average filter, wherein the input end of the biquad generalized integrator frequency locking loop is bidirectionally connected with the FPGA frequency multiplication data acquisition unit, and the output end of the biquad generalized integrator frequency locking loop is connected with the input end of the A/D converter through the delay signal elimination filter and the moving average filter in sequence.
Furthermore, the power supply unit comprises a current source unit, an LD light source, a signal processing unit, a waveform generator, a photocell, a DC-DC converter, a temperature control protection and external temperature detection circuit, a driving and protection circuit and a backup power source unit, an external power source sequentially supplies power for a peripheral circuit through the current source unit, the LD light source, the signal processing unit, the waveform generator, the photocell and the DC-DC converter, the CPU data processing unit is bidirectionally connected with the temperature control protection and external temperature detection circuit, the CPU data processing unit is connected with the LD light source through the driving and protection circuit, and the CPU data processing unit supplies power for the peripheral circuit through the backup power source unit.
Furthermore, the frequency division phase-locked loop further comprises a phase discriminator and a feedback loop, and the phase discriminator is connected with the feedback loop through a bi-quad generalized integrator frequency-locked loop, a delay signal eliminating filter and a moving average filter in sequence.
Further, the feedback loop includes a frequency feedback loop and a phase feedback loop.
Further, the system also comprises a built-in storage unit, and the built-in storage unit is connected with the output end of the CPU data processing unit.
Preferably, the shaping circuit comprises a voltage amplifier of model LMC662CN and a schmitt trigger, the voltage amplifier and the schmitt trigger being electrically connected.
Preferably, the three-phase split core type current sensor further comprises a sampling resistor, and the three-phase split core type current sensor is respectively connected with the input end of the signal filtering and amplifying circuit and the input end of the shaping circuit through the sampling resistor.
Preferably, the system further comprises a keyboard, and the keyboard is connected with the input end of the CPU data processing unit.
Preferably, the signal processing unit amplifies and filters the electric signal.
Compared with the prior art, the invention has the following beneficial effects:
1. the invention relates to an anti-harmonic interference three-phase electric energy meter on-site calibration instrument, wherein a three-phase clamp current sensor and a three-phase clamp voltage sensor are directly connected to a current end and a voltage end of an electric meter and are used for acquiring voltage and current signals of the electric meter to be tested, a CPU data processing unit processes the acquired data and transmits the data to an LED display output circuit for display; the shaping circuit shapes the acquired signal into a same-frequency pulse, a sampling time reference is provided by a standard crystal oscillator for testing clock errors arranged in a small keyboard of the calibrator, an FPGA frequency-doubling data acquisition unit processes the signal and then controls an A/D converter to perform analog-to-digital conversion in a sampling period, a frequency-division phase-locked loop is inserted between the A/D converter and the FPGA frequency-doubling data acquisition unit, the same-pulse signal is extracted through the frequency-division phase-locked loop, the purpose of suppressing harmonic interference is achieved, meanwhile, the phase difference between the reference pulse and the acquired pulse is calculated through a multiplication feedback mechanism, and a good filtering effect can be obtained.
2. The invention adds a frequency division phase-locked loop between the A/D converter and the FPGA frequency multiplication data acquisition unit, utilizes the phase-locked loop to keep the frequency phase of the frequency division phase-locked loop consistent with the input signal of the synchronous acquisition pulse, realizes the self-adaptability and anti-interference of frequency tracking, ensures that the frequency is equal to a certain extent under the condition that the phase difference between the voltage and the current of the measured running electric energy meter and the phase difference between the voltage and the current of a standard meter are constant, utilizes a frequency division feedback loop to perform feedback adjustment on the output, keeps the output digital signal undistorted, and improves the anti-harmonic interference capability.
3. The power supply unit of the invention consists of a laser energy supply part and a backup battery part, the current source unit 1201 outputs current, the current is processed by the signal processing unit and then outputs a continuous and stable LD working current which is converted into current to be transmitted to the DC-DC converter, and the current is converted by the DC-DC converter and then is supplied to a peripheral circuit; the CPU data processing unit collects the temperature of the LD light source and the external environment through the temperature control protection and external temperature detection circuit and feeds the temperature back to the CPU data processing unit, and when the CPU data processing unit detects that the temperature signal is not in the high-efficiency working range of the LD light source, the CPU data processing unit gives a pulse signal to the driving and protection circuit to stop outputting the LD light source and is connected with the standby power supply unit to supply power to the peripheral circuit at the high-voltage side; the laser energy supply part is additionally provided with the laser energy supply part, so that the service life of the calibrator can be further prolonged.
Drawings
The present invention will be described in further detail with reference to the accompanying drawings;
FIG. 1 is a schematic structural diagram of an anti-harmonic-interference three-phase electric energy meter on-site calibration instrument of the invention;
FIG. 2 is a schematic structural diagram of a frequency-division phase-locked loop in the three-phase electric energy meter on-site calibration instrument for resisting harmonic interference according to the invention;
FIG. 3 is a schematic structural diagram of a power supply unit in the three-phase electric energy meter on-site calibration instrument for resisting harmonic interference according to the invention;
in the figure: 1 is a three-phase clamp-on current sensor, 2 is a three-phase clamp-on voltage sensor, 3 is a signal filtering amplifying circuit, 4 is an A/D converter, 5 is a standard meter reference voltage and reference current input interface, 6 is a shaping circuit, 7 is a standard crystal oscillator, 8 is an FPGA frequency multiplication data acquisition unit, 9 is a frequency division phase-locked loop, 91 is a biquad generalized integrator frequency-locked loop, 92 is a delay signal elimination filter, 93 is a sliding average filter, 94 is a phase discriminator, 95 is a feedback loop, 10 is a CPU data processing unit, 11 is an LED display output circuit, 12 is a power supply unit, 1201 is a current source unit, 1202 is an LD light source, 1203 is a signal processing unit, 1204 is a waveform generator, 1205 is a photocell, 1206 is a DC-DC converter, 1207 is a temperature control protection and external temperature detection circuit, 1208 is a driving and protection circuit, and 1209 is a backup power supply unit, a built-in storage unit 13 and a keyboard 14.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments, but not all embodiments, of the present invention; all other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
As shown in fig. 1, an anti-harmonic interference three-phase electric energy meter field calibrator includes: the device comprises a three-phase clamp-on current sensor 1, a three-phase clamp-on voltage sensor 2, a signal filtering and amplifying circuit 3, an A/D converter 4, a standard meter reference voltage and reference current input interface 5, a shaping circuit 6, a standard crystal oscillator 7, an FPGA frequency multiplication data acquisition unit 8, a frequency division phase-locked loop 9, a CPU data processing unit 10, an LED display output circuit 11 and a power supply unit 12; the shaping circuit comprises a voltage amplifier with the model number of LMC662CN and a Schmitt trigger, and the voltage amplifier is electrically connected with the Schmitt trigger.
The input end of the three-phase clamp-on current sensor 1 and the input end of the three-phase clamp-on voltage sensor 2 are respectively connected with the current end and the voltage end of an electric meter, the output end of the three-phase clamp-on current sensor 1 and the output end of the three-phase clamp-on voltage sensor 2 are respectively connected with the input end of a signal filtering and amplifying circuit 3 and the input end of a shaping circuit 6, the output end of the signal filtering and amplifying circuit 3, a standard meter reference voltage and a reference current input interface 5 are respectively connected with the input end of an A/D converter 4, the output end of the shaping circuit 6 and a standard crystal oscillator 7 are respectively connected with the input end of an FPGA frequency doubling data acquisition unit 8, the output end of the FPGA frequency doubling data acquisition unit 8 is connected with an LED display output circuit 11 through a CPU data processing unit 10, the FPGA frequency doubling data acquisition unit 8 is bidirectionally connected with a frequency division phase-locked loop 9, and the frequency division phase-locked loop 9 is bidirectionally connected with the A/D converter 4, the power supply unit 12 supplies power to the CPU data processing unit 10 and peripheral circuits.
Further, the calibrator further comprises a built-in storage unit 13 and a keyboard 14, wherein the built-in storage unit 13 is connected with the output end of the CPU data processing unit 10, and the keyboard 14 is connected with the input end of the CPU data processing unit 10.
Furthermore, the three-phase pincerlike current sensor is respectively connected with the input end of the signal filtering and amplifying circuit and the input end of the shaping circuit through sampling resistors.
Specifically, the three-phase clamp-on current sensor 1 and the three-phase clamp-on voltage sensor 2 are directly connected to a current end and a voltage end of an electric meter and used for collecting voltage and current signals of the electric meter to be tested, and the CPU data processing unit 10 processes the collected data and transmits the data to the LED display output circuit 11 for display; the shaping circuit 6 shapes the acquired signal into a same-frequency pulse, the sampling time reference is provided by a standard crystal oscillator 7 for testing clock errors arranged in a small keyboard of the calibrator, the FPGA frequency-doubling data acquisition unit 8 controls the A/D converter 4 to perform analog-to-digital conversion after processing in a sampling period, a frequency-division phase-locked loop 9 is inserted between the A/D converter 4 and the FPGA frequency-doubling data acquisition unit 8, the same-pulse signal is extracted through the frequency-division phase-locked loop 9, the purpose of suppressing harmonic interference is achieved, meanwhile, the phase difference between the reference pulse and the acquired pulse is calculated through a multiplication feedback mechanism, and a better filtering effect can be obtained.
As shown in fig. 2, the frequency-division phase-locked loop 9 includes a biquad generalized integrator frequency-locked loop 91, a delay signal cancellation filter 92 and a moving average filter 93, an input end of the biquad generalized integrator frequency-locked loop 91 is bidirectionally connected to the FPGA frequency multiplication data acquisition unit 8, and an output end of the biquad generalized integrator frequency-locked loop 91 is connected to an input end of the a/D converter 4 sequentially through the delay signal cancellation filter 92 and the moving average filter 93.
The frequency division phase-locked loop 9 further comprises a phase detector 94 and a feedback loop 95, the phase detector 94 is connected with the feedback loop 95 sequentially through a biquad generalized integrator frequency-locked loop 91, a delay signal eliminating filter 92 and a moving average filter 93, and the feedback loop 95 comprises a frequency feedback loop and a phase feedback loop.
In this embodiment, the bi-quad generalized integrator frequency-division phase-locked loop 9 is an adaptive filter, and its functions mainly include data preprocessing coordinate transformation, voltage signals after coordinate transformation are calculated by the bi-quad generalized integrator, so that a part of harmonic components are eliminated, and the moving average filter 92 separates positive and negative sequence components of the grid voltage when the grid is unbalanced, and simultaneously realizes frequency tracking; the delayed signal cancellation filter 93 can filter the harmonic waves of a specific frequency according to the principle of the periodic point symmetry of the sinusoidal signal. At this time, a feedback loop 95 including two feedback loops of frequency feedback and phase feedback exists, so that even if the system has short-time or a large amount of high-frequency harmonic interference, the phase-locked loop adjusted through the feedback link can accurately track the voltage frequency and the phase signal of the power grid. Wherein a second order generalized integrator is a solution based on a 90 ° phase angle shift of the input sinusoidal signal. The input voltage signal can generate two-phase orthogonal signals after integral calculation, one path of output signal tracks the input signal, and the other path of signal realizes 90-degree phase angle shift of the input signal.
The frequency-division phase-locked loop 9 in this embodiment adopts a biquad generalized integrator phase-locked loop (DSOGI-PLL) to lock a voltage signal having the same frequency as the pulse signal, and is a typical frequency tracking phase-locked loop structure. Mainly comprises a software phase-locked loop structure consisting of a biquad generalized integrator frequency-locked loop 91, a delay signal elimination filter 92 and a moving average filter 93, a three-phase pincerlike current sensor 1 and a three-phase pincerlike voltage sensor 2 convert signals of voltage, current and the like at the side of a to-be-detected meter into small voltage and small current signals suitable for being collected by an acquisition unit, the collected small voltage and small current signals are processed by signal conditioning, filtering, A/D conversion and the like, a conversion result of an A/D converter 4 is stored in real time by an FPGA frequency doubling data collection unit 8, a digital quantity and an analog quantity are output by a digital channel and an analog channel and are finally transmitted to a CPU data processing unit 10 for unified calculation to obtain digital quantities of voltage, current, power and the like, the CPU data processing unit 10 arranges and combines the calculated data according to a certain format, the data is sent to the built-in storage unit 13 for collection and classification and is displayed by the LED display output circuit 11.
In the embodiment, the frequency division phase-locked loop 9 ensures synchronous same-frequency output, divides the frequency of the measured signal to lock, filters out other harmonic interference, can quickly lock the measured signal in a short time, can realize real storage and feedback, and realizes synchronous interval sampling of a plurality of points in a sampling period; the feedback mechanism further reduces the signal error.
As shown in fig. 3, the power supply unit 12 includes a current source unit 1201, an LD light source 1202, a signal processing unit 1203, a waveform generator 1204, a photocell 1205, a DC-DC converter 1206, a temperature control protection and ambient temperature detection circuit 1207, a driving and protection circuit 1208, and a backup power supply unit 1209, an external power supply supplies power to a peripheral circuit sequentially through the current source unit 1201, the LD light source 1202, the signal processing unit 1203, the waveform generator 1204, the photocell 1205, and the DC-DC converter 1206, the CPU data processing unit 10 is bidirectionally connected to the temperature control protection and ambient temperature detection circuit 1207, the CPU data processing unit 10 is connected to the LD light source 1202 through the driving and protection circuit 1208, and the CPU data processing unit 10 supplies power to the peripheral circuit through the backup power supply unit 1209; the signal processing unit 1203 amplifies and filters the electrical signal.
Specifically, the power supply unit 12 is composed of a laser power supply unit and a backup battery, and outputs current from the current source unit 1201, and outputs a continuously stable LD working current after being processed by the signal processing unit 1203, and the LD working current is converted into current and transmitted to the DC-DC converter 1206, and the current is converted by the DC-DC converter 1206 and then supplies power to a peripheral circuit, such as a data acquisition and processing display unit in fig. 3; the CPU data processing unit 10 collects the temperatures of the LD light source 1202 and the external environment through the temperature control protection and external temperature detection circuit 1207 and feeds back the temperatures to the CPU data processing unit 10, when the CPU data processing unit 10 detects that the temperature signal is not within the high efficiency working range of the LD light source 1202, the CPU data processing unit 10 provides a pulse signal to the driving and protection circuit 1208 to stop outputting the pulse signal to the LD light source 1202 and connects the backup power supply unit 1209 to supply power to the high voltage side peripheral circuit, such as the collection of the voltage signal and the current signal of the three-phase clamp-on current sensor 1 and the three-phase clamp-on voltage sensor 2 on the side of the measured electric meter, when the laser circuit fails, the working principle is the same as above; this embodiment is through adding at the power supply part and establishing the laser energy supply, can further improve check gauge life.
The invention relates to an anti-harmonic interference three-phase electric energy meter field calibrator, which is characterized in that when a three-phase pincerlike current sensor 1 and a three-phase pincerlike voltage sensor 2 acquire a voltage signal and a current signal of a measured electric energy meter running on the field, the sensors respectively transmit the sampling values to a signal filtering and amplifying circuit 3 and a shaping circuit 6, at the moment, the three-phase pincerlike current sensor 1 converts three-phase currents Ia, Ib and Ic into small current signals through a current transformer, and then converts the small current signals into small current signals through a sampling resistor of 0.4k omega; the three-phase pincerlike voltage sensor 2 converts voltage into a small voltage signal through a voltage transformer, and the small voltage signal is directly transmitted to the A/D converter 4 after being subjected to signal conditioning and filtering through the signal filtering and amplifying circuit 3.
The A/D converter 4 is provided with three interfaces, the first interface is connected with the acquisition signal, and the converted voltage is input into the A/D converter 4 for analog-to-digital conversion to obtain a digital signal required by the CPU data processing unit 10; the second interface is a standard meter reference voltage and reference current input interface 5; the third interface is a feedback interface of the frequency division phase-locked loop 9. At this time, the collected signals enter a shaping circuit 6 for data shaping, the shaping circuit 6 shapes the output signals to be processed by a voltage amplifier with the model of LMC662CN, a Schmitt trigger is adopted to shape the sampled original waveforms into signals with the same pulse as the check meter, and a phase FPGA frequency multiplication data acquisition unit 8 is adopted to acquire the data. A frequency division phase-locked loop 9 is inserted between an A/D converter 4 and an FPGA frequency multiplication data acquisition unit 8, the FPGA frequency multiplication data acquisition unit 8 inputs data subjected to frequency multiplication into the frequency division phase-locked loop 9, the frequency division phase-locked loop 9 locks a voltage signal with the same frequency as a pulse signal by adopting a double second order generalized integrator phase-locked loop (DSOGI-FLL), a multiplication phase discriminator 94 is added to multiply a calculated input signal and an output signal to obtain a product, the product is output by a filter and the phase discriminator to obtain the phase difference of the input and output signals, a feedback loop 95 is used for carrying out feedback type comparison and analysis on the received digital signal, the output signal locks the input signal through feedback to realize the phase locking function, the pulse signal controlled by the phase-locked loop is input into the A/D converter 4, the A/D converter 4 inputs the pulse signal output by the frequency division phase-locked loop 9, the sampling signal and the standard meter signal are synchronously amplified, and finally, the amplified sampling signal and the standard meter signal are synchronously input into a CPU data processing unit 10 for calculation, so that the aim of resisting harmonic interference is fulfilled, and finally, the obtained calculation results are respectively input into a built-in storage unit 13 and an LED display output circuit 11.
The invention adds a frequency division phase-locked loop between the A/D converter and the FPGA frequency multiplication data acquisition unit, utilizes the phase-locked loop to keep the frequency phase of the frequency division phase-locked loop consistent with the input signal of the synchronous acquisition pulse, realizes the self-adaptability and anti-interference of frequency tracking, ensures that the frequency is equal to a certain extent under the condition that the phase difference between the voltage and the current of the measured running electric energy meter and the phase difference between the voltage and the current of a standard meter are constant, utilizes a frequency division feedback loop to perform feedback adjustment on the output, keeps the output digital signal undistorted, and improves the anti-harmonic interference capability.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (10)
1. The utility model provides an anti harmonic interference's on-spot check gauge of three-phase electric energy meter which characterized in that: the method comprises the following steps: the device comprises a three-phase clamp-on current sensor, a three-phase clamp-on voltage sensor, a signal filtering and amplifying circuit, an A/D converter, a standard meter reference voltage and reference current input interface, a shaping circuit, a standard crystal oscillator, an FPGA frequency multiplication data acquisition unit, a frequency division phase-locked loop, a CPU data processing unit, an LED display output circuit and a power supply unit;
the input end of the three-phase pincerlike current sensor and the input end of the three-phase pincerlike voltage sensor are respectively connected with the current end and the voltage end of an electric meter, the output end of the three-phase pincerlike current sensor and the output end of the three-phase pincerlike voltage sensor are respectively connected with the input end of a signal filtering and amplifying circuit and the input end of a shaping circuit, the output end of the signal filtering and amplifying circuit, the reference voltage of a standard meter and the input interface of the reference current are respectively connected with the input end of an A/D converter, the output end of the shaping circuit and a standard crystal oscillator are respectively connected with the input end of an FPGA frequency doubling data acquisition unit, the output end of the FPGA frequency doubling data acquisition unit is connected with an LED display output circuit through a CPU data processing unit, the FPGA frequency doubling data acquisition unit is bidirectionally connected with a frequency division phase-locked loop, and the frequency division phase-locked loop is bidirectionally connected with the A/D converter, the power supply unit supplies power to the CPU data processing unit and the peripheral circuit.
2. The anti-harmonic-interference three-phase electric energy meter field calibrator according to claim 1, characterized in that: the frequency division phase-locked loop comprises a biquad generalized integrator frequency-locked loop, a delay signal eliminating filter and a sliding average filter, wherein the input end of the biquad generalized integrator frequency-locked loop is bidirectionally connected with the FPGA frequency multiplication data acquisition unit, and the output end of the biquad generalized integrator frequency-locked loop is connected with the input end of the A/D converter through the delay signal eliminating filter and the sliding average filter in sequence.
3. The anti-harmonic-interference three-phase electric energy meter field calibrator according to claim 1, characterized in that: the power supply unit comprises a current source unit, an LD light source, a signal processing unit, a waveform generator, a photocell, a DC-DC converter, a temperature control protection and external temperature detection circuit, a drive and protection circuit and a backup power source unit, wherein an external power source supplies power for a peripheral circuit sequentially through the current source unit, the LD light source, the signal processing unit, the waveform generator, the photocell and the DC-DC converter, the CPU data processing unit is in two-way connection with the temperature control protection and external temperature detection circuit, the CPU data processing unit is connected with the LD light source through the drive and protection circuit, and the CPU data processing unit supplies power for the peripheral circuit through the backup power source unit.
4. The harmonic interference resistant three-phase electric energy meter on-site calibrator according to claim 2, characterized in that: the frequency division phase-locked loop further comprises a phase discriminator and a feedback loop, and the phase discriminator is connected with the feedback loop through a biquad generalized integrator frequency-locked loop, a delay signal eliminating filter and a moving average filter in sequence.
5. The anti-harmonic-interference three-phase electric energy meter field calibrator according to claim 1, characterized in that: the feedback loop includes a frequency feedback loop and a phase feedback loop.
6. The anti-harmonic-interference three-phase electric energy meter field calibrator according to claim 1, characterized in that: the CPU data processing unit is connected with the CPU data processing unit through a built-in storage unit.
7. The anti-harmonic-interference three-phase electric energy meter field calibrator according to claim 1, characterized in that: the shaping circuit comprises a voltage amplifier with the model number of LMC662CN and a Schmitt trigger, and the voltage amplifier is electrically connected with the Schmitt trigger.
8. The anti-harmonic-interference three-phase electric energy meter field calibrator according to claim 1, characterized in that: the three-phase pincerlike current sensor is connected with the input end of the signal filtering and amplifying circuit and the input end of the shaping circuit through the sampling resistors respectively.
9. The anti-harmonic-interference three-phase electric energy meter field calibrator according to claim 1, characterized in that: the keyboard is connected with the input end of the CPU data processing unit.
10. The harmonic interference resistant three-phase electric energy meter on-site calibrator according to claim 3, characterized in that: the signal processing unit is used for amplifying and filtering the electric signals.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114689935A (en) * | 2022-03-24 | 2022-07-01 | 贵州电网有限责任公司 | Harmonic analysis and self-calibration circuit for electric energy metering chip |
| CN116500536A (en) * | 2023-04-14 | 2023-07-28 | 南京丹迪克电力仪表有限公司 | Method for electric energy meter direct current and even harmonic influence test and alternating current-direct current electric energy meter testing device |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114689935A (en) * | 2022-03-24 | 2022-07-01 | 贵州电网有限责任公司 | Harmonic analysis and self-calibration circuit for electric energy metering chip |
| CN116500536A (en) * | 2023-04-14 | 2023-07-28 | 南京丹迪克电力仪表有限公司 | Method for electric energy meter direct current and even harmonic influence test and alternating current-direct current electric energy meter testing device |
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