CN107515332B - Direct current electric energy metering device and method based on frequency spectrum analysis and synchronous sampling - Google Patents

Abstract

The invention discloses a direct current electric energy metering device and a method based on frequency spectrum analysis and synchronous sampling, wherein the device comprises a direct current voltage sampling module for sampling direct current voltage; the direct current sampling module is used for sampling direct current; the frequency and phase synchronization module is used for enabling the sampling frequency and the phase of the direct current voltage sampling and the sampling frequency and the phase of the direct current sampling to be the same; a frequency analysis module for processing the sampled signal using a fourier transform; the direct current electric energy calculating module is used for calculating direct current electric energy; the ripple electric energy calculating module is used for calculating ripple electric energy; the method comprises the steps of adjusting phase frequency synchronization of direct current sampling and direct voltage sampling, sampling direct current and direct voltage, and calculating after performing Fourier transform processing on a direct current sampling value and a direct voltage sampling value respectively to obtain direct current electric energy.

Description

A direct current energy metering device and method based on spectrum analysis and synchronous sampling

technical field

The invention relates to the field of electric energy measurement, and more particularly, to a direct current electric energy measurement device and method based on spectrum analysis and synchronous sampling.

Background technique

The application range of DC power is becoming more and more extensive, and DC power needs to be measured in applications such as off-board charging of electric vehicles and photovoltaic power generation. The measurement method of conventional DC energy is to sample the DC voltage and DC current respectively, and then directly multiply them to integrate the time. When the DC power is in a steady state, this method can get accurate results, but the DC power is usually dynamic. When the DC power is in a dynamic state, since the DC voltage and DC current may contain dynamic phenomena such as ripple, the sampled values are directly related to each other. The multiplied DC power value is the sum of the full wave and the ripple power. It is impossible to distinguish whether the ripple is emitted or absorbed by the metered user, and there is a measurement error; The voltage and current values deviate. Therefore, the conventional DC energy measurement method cannot meet the requirements, and a calculation method for dynamic DC energy needs to be designed.

SUMMARY OF THE INVENTION

In order to solve the measurement error problem existing in the background art for dynamic DC power, the present invention provides a DC power metering device and method based on spectrum analysis and synchronous sampling, the method can realize the synchronous sampling of dynamic DC power, and Measure each wave of DC energy separately.

A direct current electric energy metering device based on spectrum analysis and synchronous sampling, the device comprises:

A DC current sampling module, the DC current sampling module is used for sampling the DC current, and the DC current sampling module includes a signal receiving unit, and the signal receiving unit is used for adjusting the frequency of the DC current sampling according to the received frequency and the phase signal and the phase; the output end of the DC current sampling module is connected with the input end of the spectrum analysis module;

DC voltage sampling module, the DC voltage sampling module is used for sampling the DC voltage, the DC voltage sampling module includes a signal receiving unit, the signal receiving unit is used to adjust the frequency of the DC voltage sampling according to the received frequency and the phase signal and the phase; the output end of the DC voltage sampling module is connected with the input end of the spectrum analysis module;

a spectrum analysis module, which is used for performing Fourier processing on the DC current sample value and the DC voltage sample value respectively, and outputs the processed DC current component and DC voltage component to the DC power calculation module; The ripple current component and the ripple voltage component are output to the ripple energy calculation module;

a DC power calculation module, the DC power calculation module is used for calculating the DC power; and

Ripple electric energy calculation module, the ripple electric energy calculation module is used for each order of ripple electric energy corresponding to each order of harmonics.

Further, the device includes a phase frequency synchronization module, the output end of the phase frequency synchronization module is connected with the signal receiving unit of the DC current sampling module and the signal receiving unit of the DC voltage sampling module, and the phase frequency synchronization module sends out the same frequency. and the phase signal to the signal receiving unit of the DC current sampling module and the signal receiving unit of the DC voltage sampling signal;

Further, the DC current sampling module includes a signal sending unit, and the signal sending unit of the DC current sampling module is connected with the signal receiving unit of the DC voltage sampling module, and is used to make the frequency and phase signals of the DC voltage sampling module and the DC current. The sampling module is the same;

Further, the DC voltage sampling module includes a signal sending unit, and the signal sending unit of the DC voltage sampling module is connected with the signal receiving unit of the DC current sampling module, and is used to make the frequency and phase signals of the DC current sampling module and the DC voltage. The sampling module is the same;

Further, the DC voltage sampling module is a resistance-divider voltage transformer capable of sending and receiving frequency and phase control signals;

Further, the DC current sampling module is a feedthrough current-limiting transformer capable of sending and receiving frequency and phase control signals;

Further, the phase frequency synchronization module is a signal generator.

A direct current energy metering method based on spectrum analysis and synchronous sampling, the method comprises:

Step 1, adjust the phase frequency synchronization, so that the sampling frequency and phase of the DC current sampling are the same as the sampling frequency and phase of the DC voltage sampling;

Step 2, sampling the DC current to be measured, and sampling the DC voltage to be measured;

Step 3, respectively performing Fourier transform processing on the sampled value of the DC current and the sampled value of the DC voltage; and

Step 4, using the DC current component and the DC voltage component processed by the Fourier transform to calculate the DC power, and using the ripple current components and the ripple voltage components obtained after the Fourier transform processing to calculate each time. sub-ripple energy.

Further, the adjusting the phase frequency synchronization refers to using the phase frequency synchronization module to send the phase frequency adjustment signal to the DC current sampling module and the DC voltage sampling module;

Further, adjusting the phase and frequency synchronization means that the DC current sampling module sends its sampling signal phase and frequency to the DC voltage sampling module, and the DC voltage sampling module adjusts the DC voltage sampling using the same phase and frequency according to the received DC current sampling signal phase and frequency. frequency;

Further, adjusting the phase and frequency synchronization means that the DC voltage sampling module sends its sampling signal phase and frequency to the DC current sampling module, and the DC current sampling module adjusts the DC current sampling using the same phase and frequency according to the received DC voltage sampling signal phase and frequency. frequency;

Further, the frequencies of the DC current component and the DC voltage component after the Fourier transform are both zero.

The beneficial effects of the present invention are as follows: the technical solution of the present invention provides a DC power metering device and method based on spectrum analysis and synchronous sampling, the method improves the accuracy of dynamic DC power measurement, and solves the problem of dynamic The method distinguishes between DC power and ripple power, and measures each ripple separately, and can determine whether the user is the sender or the absorber of ripple according to the measurement results, providing future DC power management. At the same time, this method can measure both DC power and AC power, which provides a technical basis for the hybrid metering technology of AC and DC power.

Description of drawings

Exemplary embodiments of the present invention may be more fully understood by reference to the following drawings:

1 is a structural diagram of a DC energy metering device with a frequency-phase synchronization module according to a specific embodiment of the present invention;

FIG. 2 is a structural diagram of a DC energy metering device with a DC current sampling module and a signal sending unit according to a specific embodiment of the present invention;

3 is a structural diagram of a DC energy metering device with a DC voltage sampling module and a signal sending unit according to a specific embodiment of the present invention;

4 is a flow chart of a method for measuring direct current energy based on spectrum analysis and synchronous sampling according to a specific embodiment of the present invention; and

FIG. 5 is a structural diagram of a field calibrator for an off-board charger of an electric vehicle using a DC measurement method based on spectrum analysis and synchronous sampling according to a specific embodiment of the present invention.

Detailed ways

Exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, however, the present invention may be embodied in many different forms and is not limited to the embodiments described herein, which are provided for the purpose of this thorough and complete disclosure invention, and fully convey the scope of the invention to those skilled in the art. The terms used in the exemplary embodiments shown in the drawings are not intended to limit the invention. In the drawings, the same elements/elements are given the same reference numerals.

Unless otherwise defined, terms (including scientific and technical terms) used herein have the commonly understood meanings to those skilled in the art. In addition, it is to be understood that terms defined in commonly used dictionaries should be construed as having meanings consistent with the context in the related art, and should not be construed as idealized or overly formal meanings.

1 is a structural diagram of a DC energy metering device with a frequency-phase synchronization module according to a specific embodiment of the present invention; the device includes:

A DC current sampling module 101, the DC current sampling module 101 is used for sampling the DC current, and the DC current sampling module includes a signal receiving unit, and the signal receiving unit is used for adjusting the DC current sampling according to the received frequency and phase signals frequency and phase; the output end of the DC current sampling module 101 is connected to the input end of the spectrum analysis module 103;

DC voltage sampling module 102, the DC voltage sampling module 102 is used for sampling the DC voltage, the DC voltage sampling module includes a signal receiving unit, the signal receiving unit is used for adjusting the DC voltage sampling according to the received frequency and phase signals frequency and phase; the output end of the DC voltage sampling module 102 is connected to the input end of the spectrum analysis module 103;

Spectrum analysis module 103, which is used to perform Fourier processing on the DC current sample value and the DC voltage sample value respectively, and output the processed DC current component and DC voltage component to the DC power calculation module 104; The processed ripple current component and the ripple voltage component are output to the ripple electric energy calculation module 105;

A DC power calculation module 104, the DC power calculation module 104 is used for calculating the DC power;

Ripple electric energy calculation module 105, the ripple electric energy calculation module 105 is used for each order of ripple electric energy corresponding to each order of harmonics;

The phase frequency synchronization module 106, the output end of the phase frequency synchronization module 106 is connected with the signal receiving unit of the DC current sampling module 101 and the signal receiving unit of the DC voltage sampling module 102, and the phase frequency synchronization module 106 sends out the same frequency and phase the signal to the signal receiving unit of the DC current sampling module and the signal receiving unit of the DC voltage sampling signal;

Further, the DC voltage sampling module is a resistance-divider voltage transformer capable of sending and receiving frequency and phase control signals;

Further, the DC current sampling module is a feedthrough current-limiting transformer capable of sending and receiving frequency and phase control signals;

Further, the phase frequency synchronization module is a signal generator.

2 is a structural diagram of a DC energy metering device with a DC current sampling module and a signal sending unit according to a specific embodiment of the present invention; the device includes:

DC current sampling module 201, the DC current sampling module 201 is used for sampling DC current, the DC current sampling module 201 includes a signal sending unit, the signal sending unit of the DC current sampling module 201 and the DC voltage sampling module 202 The signal receiving unit is connected to the DC voltage sampling module 202 to make the frequency and phase signal the same as the DC current sampling module 201; the output end of the DC current sampling module 201 is connected to the input end of the spectrum analysis module 203;

DC voltage sampling module 202, the DC voltage sampling module 202 is used for sampling the DC voltage, the DC voltage sampling module includes a signal receiving unit, the signal receiving unit is used for adjusting the DC voltage sampling according to the received frequency and phase signals frequency and phase; the output end of the DC voltage sampling module 202 is connected to the input end of the spectrum analysis module 203;

Spectrum analysis module 203, which is used to perform Fourier processing on the DC current sample value and the DC voltage sample value respectively, and output the processed DC current component and DC voltage component to the DC power calculation module 204; The processed ripple current component and the ripple voltage component are output to the ripple electric energy calculation module 205;

The DC power calculation module 204, the DC power calculation module 204 is used for calculating the DC power;

Ripple electric energy calculation module 205, the ripple electric energy calculation module 205 is used for each order of ripple electric energy corresponding to each order of harmonics;

Further, the DC voltage sampling module is a resistance-divider voltage transformer capable of sending and receiving frequency and phase control signals;

Further, the DC current sampling module is a feedthrough current-limiting transformer capable of sending and receiving frequency and phase control signals;

Further, the phase frequency synchronization module is a signal generator.

3 is a structural diagram of a DC energy metering device with a DC voltage sampling module and a signal sending unit according to a specific embodiment of the present invention; the device includes:

A DC current sampling module 301, the DC current sampling module 301 is used for sampling the DC current, the DC current sampling module includes a signal receiving unit, and the signal receiving unit is used for adjusting the DC current sampling according to the received frequency and phase signals frequency and phase; the output end of the DC current sampling module 301 is connected to the input end of the spectrum analysis module 303;

DC voltage sampling module 302, the DC voltage sampling module 302 is used for sampling the DC voltage, the DC voltage sampling module 302 includes a signal sending unit, the signal sending unit of the DC voltage sampling module 302 and the DC current sampling module 301 The signal receiving unit is connected to the DC current sampling module 301 to make the frequency and phase signals the same as the DC voltage sampling module 302; the output end of the DC voltage sampling module 302 is connected to the input end of the spectrum analysis module 303;

The spectrum analysis module 303 is used to perform Fourier processing on the DC current sample value and the DC voltage sample value respectively, and output the processed DC current component and DC voltage component to the DC power calculation module 304; The processed ripple current component and the ripple voltage component are output to the ripple electric energy calculation module 305;

A DC power calculation module 304, the DC power calculation module 304 is used for calculating the DC power;

Ripple electric energy calculation module 305, the ripple electric energy calculation module 305 is used for each order of ripple electric energy corresponding to each order of harmonics;

Further, the DC voltage sampling module is a resistance-divider voltage transformer capable of sending and receiving frequency and phase control signals;

Further, the DC current sampling module is a feedthrough current-limiting transformer capable of sending and receiving frequency and phase control signals;

Further, the phase frequency synchronization module is a signal generator.

4 is a flow chart of a method for measuring direct current energy based on spectrum analysis and synchronous sampling according to a specific embodiment of the present invention, the method includes:

Step 401, adjusting the phase-frequency synchronization, so that the sampling frequency and phase of the DC current sampling are the same as the sampling frequency and phase of the DC voltage sampling;

Step 402, sampling the DC current to be measured, and sampling the DC voltage to be measured;

Step 403, respectively performing Fourier transform processing on the DC current sample value and the DC voltage sample value; and

Step 404, using the DC current component and the DC voltage component processed by the Fourier transform to calculate the DC power, and using the ripple current components and the ripple voltage components obtained after the Fourier transform processing to calculate each time. sub-ripple energy.

Further, the adjusting the phase frequency synchronization refers to using the phase frequency synchronization module to send the phase frequency adjustment signal to the DC current sampling module and the DC voltage sampling module;

Further, adjusting the phase and frequency synchronization means that the DC current sampling module sends its sampling signal phase and frequency to the DC voltage sampling module, and the DC voltage sampling module adjusts the DC voltage sampling using the same phase and frequency according to the received DC current sampling signal phase and frequency. frequency;

Further, adjusting the phase and frequency synchronization means that the DC voltage sampling module sends its sampling signal phase and frequency to the DC current sampling module, and the DC current sampling module adjusts the DC current sampling using the same phase and frequency according to the received DC voltage sampling signal phase and frequency. frequency;

Further, the frequencies of the DC current component and the DC voltage component after the Fourier transform are both zero.

FIG. 5 is a structural diagram of a field calibrator for an off-board charger of an electric vehicle using a DC measurement method based on spectrum analysis and synchronous sampling according to a specific embodiment of the present invention.

The on-site calibrator of the off-board charger for electric vehicles is used for on-site energy measurement of the off-board charger of the electric vehicle. Heart-type current transformer, using the pulse synchronization method to synchronize the phase and frequency of the feed-through current transformer and the resistance-dividing voltage transformer; the DC voltage sampling result and the DC current sampling result are analyzed by Fourier The voltage of each wave and the current of each wave are obtained by transformation, and the voltage and current of each wave are correspondingly input into the electric energy calculation module of each wave to calculate the electric energy of each wave.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention. Thus, provided that these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims (11)

1. A direct current energy metering device based on spectrum analysis and synchronous sampling, the device comprising: A DC current sampling module, the DC current sampling module is used for sampling the DC current, and the DC current sampling module includes a signal receiving unit, and the signal receiving unit is used for adjusting the frequency of the DC current sampling according to the received frequency and the phase signal and the phase; the output end of the DC current sampling module is connected with the input end of the spectrum analysis module; DC voltage sampling module, the DC voltage sampling module is used for sampling the DC voltage, the DC voltage sampling module includes a signal receiving unit, the signal receiving unit is used to adjust the frequency of the DC voltage sampling according to the received frequency and the phase signal and the phase; the output end of the DC voltage sampling module is connected with the input end of the spectrum analysis module; a spectrum analysis module, which is used for performing Fourier processing on the DC current sample value and the DC voltage sample value respectively, and outputs the processed DC current component and DC voltage component to the DC power calculation module; The ripple current component and the ripple voltage component are output to the ripple energy calculation module; A phase-frequency synchronization module, the output end of the phase-frequency synchronization module is connected to the signal receiving unit of the DC current sampling module and the signal receiving unit of the DC voltage sampling module, and the phase-frequency synchronization module sends the same frequency and phase signals to the DC current sampling a signal receiving unit of the module and a signal receiving unit of the DC voltage sampling signal; a DC power calculation module, the DC power calculation module is used for calculating the DC power; and Ripple electric energy calculation module, the ripple electric energy calculation module is used to calculate each order of ripple electric energy corresponding to each order of harmonics. 2. A direct current energy metering device based on spectrum analysis and synchronous sampling, the device comprising: A DC current sampling module, the DC current sampling module is used for sampling the DC current, and the DC current sampling module includes a signal receiving unit, and the signal receiving unit is used for adjusting the frequency of the DC current sampling according to the received frequency and the phase signal and the phase; the output end of the DC current sampling module is connected with the input end of the spectrum analysis module; DC voltage sampling module, the DC voltage sampling module is used for sampling the DC voltage, the DC voltage sampling module includes a signal receiving unit, the signal receiving unit is used to adjust the frequency of the DC voltage sampling according to the received frequency and the phase signal and the phase; the output end of the DC voltage sampling module is connected with the input end of the spectrum analysis module; a spectrum analysis module, which is used for performing Fourier processing on the DC current sample value and the DC voltage sample value respectively, and outputs the processed DC current component and DC voltage component to the DC power calculation module; The ripple current component and the ripple voltage component are output to the ripple energy calculation module; a DC power calculation module, the DC power calculation module is used for calculating the DC power; and Ripple electric energy calculation module, the ripple electric energy calculation module is used to calculate each order of ripple electric energy corresponding to each order of harmonics; The DC current sampling module includes a signal sending unit, and the signal sending unit of the DC current sampling module is connected to the signal receiving unit of the DC voltage sampling module, and is used for making the frequency and phase signals of the DC voltage sampling module and the DC current sampling module same. 3. A direct current energy metering device based on spectrum analysis and synchronous sampling, the device comprising: A DC current sampling module, the DC current sampling module is used for sampling the DC current, and the DC current sampling module includes a signal receiving unit, and the signal receiving unit is used for adjusting the frequency of the DC current sampling according to the received frequency and the phase signal and the phase; the output end of the DC current sampling module is connected with the input end of the spectrum analysis module; DC voltage sampling module, the DC voltage sampling module is used for sampling the DC voltage, the DC voltage sampling module includes a signal receiving unit, the signal receiving unit is used to adjust the frequency of the DC voltage sampling according to the received frequency and the phase signal and the phase; the output end of the DC voltage sampling module is connected with the input end of the spectrum analysis module; a spectrum analysis module, which is used for performing Fourier processing on the DC current sample value and the DC voltage sample value respectively, and outputs the processed DC current component and DC voltage component to the DC power calculation module; The ripple current component and the ripple voltage component are output to the ripple energy calculation module; a DC power calculation module, the DC power calculation module is used for calculating the DC power; and Ripple electric energy calculation module, the ripple electric energy calculation module is used to calculate each order of ripple electric energy corresponding to each order of harmonics; The DC voltage sampling module includes a signal sending unit, and the signal sending unit of the DC voltage sampling module is connected to the signal receiving unit of the DC current sampling module, and is used for making the frequency and phase signals of the DC current sampling module and the DC voltage sampling module same. 4. The device according to any one of claims 1-3, wherein the DC voltage sampling module is a resistance-divider voltage transformer capable of sending and receiving frequency and phase control signals. 5 . The device according to claim 1 , wherein the DC current sampling module is a feedthrough current-limiting transformer capable of sending and receiving frequency and phase control signals. 6 . 6 . The device according to claim 1 , wherein the phase-frequency synchronization module is a signal generator. 7 . 7. A direct current energy metering method based on spectrum analysis and synchronous sampling, the method comprising: Step 1, adjust the phase frequency synchronization, so that the sampling frequency and phase of the DC current sampling are the same as the sampling frequency and phase of the DC voltage sampling; Step 2, sampling the DC current to be measured, and sampling the DC voltage to be measured; Step 3, respectively performing Fourier transform processing on the sampled value of the DC current and the sampled value of the DC voltage; and Step 4, using the DC current component and the DC voltage component processed by the Fourier transform to calculate the DC electric energy; using the ripple current components and the ripple voltage components obtained after the Fourier transform processing to calculate each time. sub-ripple energy. 8 . The method according to claim 7 , wherein adjusting the phase-frequency synchronization means sending a phase-frequency adjustment signal to the DC current sampling module and the DC voltage sampling module by using the phase-frequency synchronization module. 9 . 9 . The method according to claim 7 , wherein the adjusting phase and frequency synchronization means that the DC current sampling module sends its sampling signal phase and frequency to the DC voltage sampling module, and the DC voltage sampling module is based on the received DC current sampling signal. 10 . Phase and Frequency Adjustment DC voltage samples use the same phase and frequency. 10 . The method according to claim 7 , wherein the adjusting phase and frequency synchronization means that the DC voltage sampling module sends its sampling signal phase and frequency to the DC current sampling module, and the DC current sampling module is based on the received DC voltage sampling signal. 11 . Phase and Frequency Adjustment DC current sampling uses the same phase and frequency. 11 . The method according to claim 7 , wherein the frequency of the DC current component and the DC voltage component after the Fourier transformation are both zero. 12 .

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