CN111628642A - Multiband harmonic wave recording starting circuit - Google Patents

Multiband harmonic wave recording starting circuit Download PDF

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Publication number
CN111628642A
CN111628642A CN202010373409.3A CN202010373409A CN111628642A CN 111628642 A CN111628642 A CN 111628642A CN 202010373409 A CN202010373409 A CN 202010373409A CN 111628642 A CN111628642 A CN 111628642A
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China
Prior art keywords
resistor
operational amplifier
input end
output end
circuit
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CN202010373409.3A
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吴为
洪潮
曾德辉
赵睿
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China South Power Grid International Co ltd
China Southern Power Grid Co Ltd
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China South Power Grid International Co ltd
China Southern Power Grid Co Ltd
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Priority to CN202010373409.3A priority Critical patent/CN111628642A/en
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/36—Means for starting or stopping converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/01—Arrangements for reducing harmonics or ripples
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/40—Arrangements for reducing harmonics

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Networks Using Active Elements (AREA)

Abstract

The invention discloses a multiband harmonic wave recording starting circuit, which is provided with a signal input end and a signal output end, wherein the signal input end is used for inputting analog quantity voltage signals of different frequency bands in a power grid, and the signal output end is used for outputting starting harmonic wave recording signals; the multiband harmonic wave recording starting circuit comprises a filter module, a full-wave precision rectifying module and an integral comparison module; the signal input end is connected with the input end of the filter module, the output end of the filter module is connected with the input end of the full-wave precise rectification module, the output end of the full-wave precise rectification module is connected with the input end of the integral comparison module, and the output end of the integral comparison module is connected with the signal output end. The method can extract the harmonic content in different frequency bands in the power transmission network, further start harmonic wave recording when the harmonic content in a specific frequency band exceeds the standard, meet the requirement of harmonic wave recording of the power network, and effectively reduce unnecessary wave recording processing.

Description

Multiband harmonic wave recording starting circuit
Technical Field
The invention relates to the technical field of harmonic detection of an alternating current and direct current power grid of a power system, in particular to a multiband harmonic wave recording starting circuit.
Background
With the continuous development and application of power electronic technology, power systems are in a trend of power electronics. The power electronic equipment injects a large amount of harmonic components into the power transmission network, so that voltage and current waveform distortion is caused, harmonic oscillation of a power system is caused, and the harmonic oscillation becomes an important factor directly influencing safe and stable operation of the system. It is therefore becoming increasingly important to efficiently detect harmonic content in grid signals to better detect harmonic problems in operating power systems.
After detecting harmonic components in the power grid signal, wave recording needs to be started when the harmonic content exceeds the standard, so that generation of harmonics is better analyzed, and corresponding countermeasures are made. In an actually-operated power grid, the possible harm brought by harmonic components of different frequency bands is different, and engineers often pay more attention to whether the harmonic content of a specific frequency band is within a safety limit during operation and maintenance, so that the harmonic components of each frequency band of the power grid need to be extracted, and a corresponding wave recording starting judgment standard needs to be set for each frequency band. Therefore, a multiband harmonic recording start circuit is urgently needed.
Disclosure of Invention
The embodiment of the invention provides a multiband harmonic wave recording starting circuit which can extract the harmonic wave content in different frequency bands in a power transmission network, further start harmonic wave recording when the harmonic wave content in a specific frequency band exceeds the standard, meet the requirement of power grid harmonic wave recording and effectively reduce unnecessary wave recording processing.
An embodiment of the invention provides a multiband harmonic wave recording starting circuit, which is provided with a signal input end and a signal output end, wherein the signal input end is used for inputting analog quantity voltage signals of different frequency bands in a power grid, and the signal output end is used for outputting starting harmonic wave recording signals;
the multiband harmonic wave recording starting circuit comprises a filter module, a full-wave precision rectifying module and an integral comparison module; the signal input end is connected with the input end of the filter module, the output end of the filter module is connected with the input end of the full-wave precise rectification module, the output end of the full-wave precise rectification module is connected with the input end of the integral comparison module, and the output end of the integral comparison module is connected with the signal output end.
As an improvement of the above scheme, the filter module is composed of at least one low-pass filter, at least two band-pass filters and at least one high-pass filter;
the signal input end is connected with the input ends of the low-pass filter, the band-pass filter and the high-pass filter, and the output ends of the low-pass filter, the band-pass filter and the high-pass filter are connected with the output end of the filter module.
As an improvement of the above scheme, the full-wave precision rectification module comprises at least four full-wave precision rectification circuits;
the input end of the full-wave precise rectifying circuit is connected with the output ends of the low-pass filter, the band-pass filter and the high-pass filter in a one-to-one correspondence manner; and the output end of the full-wave precise rectification circuit is connected with the output end of the full-wave precise rectification module.
As an improvement of the above scheme, the integral comparison module comprises at least four voltage integration circuits and at least four voltage comparison circuits;
the output end of the voltage integrating circuit is connected with the input end of the voltage comparing circuit, the input end of the voltage integrating circuit is connected with the output end of the full-wave precision rectifying circuit in a one-to-one correspondence mode, and the output end of the voltage comparing circuit is connected with the signal output end.
As an improvement of the scheme, the low-pass filter is an LTC1069-1 low-pass switched capacitor filter, the band-pass filter is an LTC1067 universal switched capacitor filter, and the high-pass filter is an LTC-1067-50 universal switched capacitor filter.
As an improvement of the above scheme, the full-wave precision rectifying circuit comprises a first operational amplifier, a second operational amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, a first diode and a second diode;
the input end of the full-wave precision rectifying circuit is connected with the first end of the first resistor;
the second end of the first resistor, the first end of the third resistor and the cathode of the first diode are connected with the inverting input end of the first operational amplifier, the non-inverting input end of the first operational amplifier is grounded through the second resistor, and the output end of the first operational amplifier is connected with the cathode of the second diode;
the second end of the third resistor is connected with the anode of the second diode, and the anode of the first diode is connected with the output end of the first operational amplifier;
a first end of the fourth resistor is connected with the anode of the second diode, a second end of the fourth resistor, a second end of the fifth resistor and a first end of the seventh resistor are connected with the inverting input end of the second operational amplifier, and a first end of the fifth resistor is connected with a first end of the first resistor; the positive phase input end of the second operational amplifier is grounded through the sixth resistor; and the output end of the second operational amplifier is connected with the second end of the seventh resistor and the output end of the full-wave precision rectifying circuit.
As an improvement of the above scheme, the voltage integrating circuit includes a third operational amplifier, an eighth resistor, a ninth resistor, and a first capacitor;
a signal input end of the voltage integrating circuit is connected with an inverting input end of the third operational amplifier through the eighth resistor, and a non-inverting input end of the third operational amplifier is grounded through the ninth resistor;
the first end of the first capacitor is connected with the inverting input end of the third operational amplifier, and the output end of the third operational amplifier is connected with the second end of the first capacitor and the signal output end of the voltage integrating circuit.
As a modification of the above aspect, the voltage comparison circuit includes a fourth operational amplifier, a tenth resistor, an eleventh resistor, and a twelfth resistor;
the inverting input end of the fourth operational amplifier is connected with the reference voltage input end of the voltage comparison circuit, and the non-inverting input end of the fourth operational amplifier is connected with the signal input end of the voltage comparison circuit; and a power supply input end of the fourth operational amplifier is connected with an external power supply and a first end of the twelfth resistor, and an output end of the fourth operational amplifier is connected with a second end of the twelfth resistor and a signal output end of the voltage comparison circuit.
As an improvement of the above scheme, the first operational amplifier, the second operational amplifier, the third operational amplifier and the fourth operational amplifier are OP285 operational amplifiers.
Compared with the prior art, the multiband harmonic wave recording starting circuit disclosed by the embodiment of the invention has the following beneficial effects:
the multiband harmonic wave recording starting circuit is provided with a signal input end for inputting analog quantity voltage signals of different frequency bands in a power grid and a signal output end for outputting starting harmonic wave recording signals; the multiband harmonic wave recording starting circuit comprises a filter module, a full-wave precision rectifying module and an integral comparison module; the signal input end is connected with the input end of the filter module, the output end of the filter module is connected with the input end of the full-wave precise rectification module, the output end of the full-wave precise rectification module is connected with the input end of the integral comparison module, and the output end of the integral comparison module is connected with the signal output end. By arranging the filter module, the harmonic content in different frequency bands in the power transmission network can be extracted; the full-wave precise rectification module is arranged to process the signals extracted from the frequency band, weak alternating-current voltage can be converted into direct-current voltage to be output, and therefore the voltage comparison circuit can perform starting wave recording standard judgment on the weak signals and has high precision; through setting up the integral comparison module, set up corresponding adjustable reference voltage to each appointed frequency channel to start the harmonic wave recording when certain specific frequency channel harmonic content exceeds standard, make the standard that different frequency channel harmonics started the wave recording accord with the operation of actual electric wire netting more, satisfied the requirement of electric wire netting harmonic wave recording, and can effectively reduce unnecessary wave recording and handle, simple structure, the operation of being convenient for.
Drawings
Fig. 1 is a schematic structural diagram of a multiband harmonic recording start circuit according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of a filter module according to an embodiment of the present invention;
fig. 3 is a schematic structural diagram of a full-wave precision rectifying circuit according to an embodiment of the present invention;
fig. 4 is a schematic structural diagram of a voltage integrating circuit according to an embodiment of the present invention;
fig. 5 is a schematic structural diagram of a voltage comparison circuit according to an embodiment of the present invention.
Detailed Description
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 only a part of the embodiments of the present invention, and not all of the embodiments. 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.
Referring to fig. 1, it is a schematic structural diagram of a multiband harmonic wave recording start circuit according to an embodiment of the present invention, where the multiband harmonic wave recording start circuit has a signal input terminal V1 for inputting analog quantity voltage signals of different frequency bands in a power grid, and a signal output terminal V2 for outputting a start harmonic wave recording signal;
the multiband harmonic wave recording starting circuit comprises a filter module 1, a full-wave precision rectifying module 2 and an integral comparison module 3; the signal input end V1 is connected with the input end of the filter module 1, the output end of the filter module 1 is connected with the input end of the full-wave precision rectification module 2, the output end of the full-wave precision rectification module 2 is connected with the input end of the integral comparison module 3, and the output end of the integral comparison module 3 is connected with the signal output end V2.
It should be noted that the invention is applicable to 110kV and above power grids, and performs harmonic measurement on the power transmission grid.
According to the multiband harmonic wave recording starting circuit provided by the embodiment of the invention, the harmonic wave content in different frequency bands in the power transmission network can be extracted by arranging the filter module; the full-wave precise rectification module is arranged to process the signals extracted from the frequency band, weak alternating-current voltage can be converted into direct-current voltage to be output, and therefore the voltage comparison circuit can perform starting wave recording standard judgment on the weak signals and has high precision; through setting up the integral comparison module, set up corresponding adjustable reference voltage to each appointed frequency channel to start the harmonic wave recording when certain specific frequency channel harmonic content exceeds standard, make the standard that different frequency channel harmonics started the wave recording accord with the operation of actual electric wire netting more, satisfied the requirement of electric wire netting harmonic wave recording, and can effectively reduce unnecessary wave recording and handle, simple structure, the operation of being convenient for.
In a preferred embodiment, referring to fig. 1, the filter module 1 is composed of at least one low-pass filter 11, at least two band-pass filters 12 and at least one high-pass filter 13;
the signal input end V1 is connected to the input ends of the low pass filter 11, the band pass filter 12 and the high pass filter 13, and the output ends of the low pass filter 11, the band pass filter 12 and the high pass filter 13 are connected to the output end of the filter module 1.
In an alternative embodiment, the low pass filter 11 is provided with one, through which low band input signals of 0-300Hz of the grid are extracted by the low pass filter 11. The two band-pass filters 12 are arranged, and the input signals of the frequency ranges of 300-900Hz and 900-1500Hz of the power grid are respectively extracted through the two band-pass filters 12. The high-pass filter 13 is provided with one, the high-frequency band input signals of 1500-2500Hz of the power grid are extracted through the high-pass filter 13, and the extraction of 50-th harmonic and the following voltage signals of the power grid can be realized through the total frequency band width of 2500 Hz.
Preferably, the low-pass filter 11 is an LTC1069-1 low-pass switched capacitor filter, the band-pass filter 12 is an LTC1067 general switched capacitor filter, and the high-pass filter 13 is an LTC-1067-50 general switched capacitor filter.
Exemplarily, referring to fig. 2, which is a schematic structural diagram of a filter module according to an embodiment of the present invention, fig. 2(a) is a schematic structural diagram of a LTC1067 general switched capacitor filter, where V + and V-respectively represent power supplies of positive and negative electrodes of the filter, and a low-noise linear power supply is generally used; SA, SB denote the summing input pins; INVA, INVB denote inverting input pins; LPA, LPB, HPA/NA, HPB/NB, BPA, BPB represent low pass, high pass, band pass filter output pins, each second order part of the filter has three outputs; AGND represents simulated ground; CLK represents the clock input and can modify the center frequency of the filter by modifying the external resistance value, with a 100:1 ratio of its internal clock to center frequency for the LTC1067 general switched capacitor filter and a 50:1 ratio of its internal clock to center frequency for the LTC1067-50 general switched capacitor filter.
In this embodiment, the positive power pin V + of the filter is connected to the 3.3V power supply and grounded through the second capacitor C2, and the negative power pin V-of the filter is connected to fclk500kHZ power and ground, AGND pin is grounded through a third capacitor C3. More specifically, the capacitance value of the second capacitor C2 is 0.1 μ F, and the capacitance value of the third capacitor C3 is 1 μ F. Summing input pin SA is connected to filter output pin LPA and summing input pin SB is connected to filter output pin LPB. The signal input end is used for inputting a grid analog quantity voltage signal, the signal input end IN is connected with a first end of a thirteenth resistor R13, a second end of a thirteenth resistor R13 is connected with an inverting input pin INVA, a filter output pin BPA is connected with a second end of a thirteenth resistor R13 through a fifteenth resistor R15, and a filter output pin HPA/NA is connected with a second end of a thirteenth resistor R13 through a fourteenth resistor R14. Eighteenth resistor R18 thOne terminal is connected to the filter output pin BPA and the second terminal of the eighteenth resistor R18 is connected to the inverting input pin INVB. The filter output pin HPB/NB is connected to the second terminal of the eighteenth resistor R18 through a sixteenth resistor R16, and the filter output pin BPB is connected to the second terminal of the eighteenth resistor R18 through a seventeenth resistor R17. The filter output pin BPB is connected to the signal output terminal OUT. Therefore, the center frequency of the filter can be adjusted by modifying the external resistance value, the band-pass and high-pass gain of the filter and the-3 dB bandwidth of the output response of the filter can be adjusted by adjusting the resistances and the structures of the resistors R13, R14, R15, R16, R17 and R18, and then the extraction of any frequency band signal in the analog voltage signal input by the power grid can be realized.
In addition, the main technical parameters of the general switched capacitor filter LTC1067 are as follows:
(1) the second-order switch capacitor building module with high precision and wide dynamic range is formed, and each building module and the resistor provide a second-order filter function together. The dual-channel second-order filter packaged by the 16-pin SSOP has a dynamic range larger than 80dB when a single 3.3V power supply is adopted, clock-to-center frequency ratios are 100:1(LTC1067) and 50:1(LTC1067-50), and internal sampling-to-center frequency ratios are 200:1(LTC1067) and 100:1(LTC 1067-50).
(2) The central frequency error is less than +/-0.2%, and has less than 40 μ VRMSThe low noise characteristic of (1) is that the quality factor Q is less than or equal to 5, the power consumption is 500mV, and the device is provided with an internal resistor and can be customized.
Referring to fig. 2(a), a schematic structural diagram of the LTC1069-1 low-pass switched capacitor filter is shown, where V + and V-respectively represent power supplies for positive and negative electrodes of the filter, and a low-noise linear power supply is generally used; AGND denotes analog ground, the quality of which determines the performance of the filter, typically using an analog ground plane around the package; vINRepresents the filter input pin, connected to the inverting input of the operational amplifier through a 43k internal resistor; vOUTRepresents the filter output pin; CLK denotes the clock input, the input frequency of the external clock is 300kHz, and the cut-off frequency of the filter is equal to the clock frequency divided by 100.
In this embodiment, referring to fig. 2(a), the AGND pin passes throughThe fourth capacitor C4 is connected to ground and the NC pin is connected to ground. The positive power supply pin V + of the filter is connected with a 3.3V power supply and is connected with the first end of the fifth capacitor C5, and the second end of the fifth capacitor C5 is grounded. More specifically, the capacitance value of the fourth capacitor C4 is 0047 μ F, and the capacitance value of the fifth capacitor C5 is 0.1 μ F. Input pin V of analog quantity voltage signal of power grid from filterINInputting and extracting low-frequency band signal from output pin V of filterOUTAnd (6) outputting. And a negative power supply pin V-NC of the filter is grounded. By adjusting the external clock frequency of the filter, the cut-off frequency of the filter can be adjusted, the output response of the filter is changed, and therefore the extraction of the specific low-frequency band signal can be achieved.
In addition, the main technical parameters of the low-pass switch capacitor filter LTC1069-1 are as follows:
(1) single-chip 8-order low-pass filter with clocked adjustable cut-off frequency (f)CUTOFF) Equal to the clock frequency divided by 100. f. ofCUTOFFThe gain of (A) is-0.7 dB, the typical passband ripple is +/-0.15 dB, and the maximum is 0.9fCUTOFF。
(2) 8 th order elliptic filter packaged by SO-8 at 1.2fCUTOFFThe attenuation of the stopband is 20dB and 1.4fCUTOFFThe time-stop band attenuation is 52dB, 2fCUTOFFThe stopband attenuation is 70 dB.
(3) With a wide dynamic range, broadband noise of 110 μ VRMS, a signal-to-noise ratio of 70dB or more, other filter responses with lower power or higher speed can be obtained.
In a preferred embodiment, the full-wave precision rectification module comprises at least four full-wave precision rectification circuits 21;
the input end of the full-wave precision rectifying circuit 21 is correspondingly connected with the output ends of the low-pass filter 11, the band-pass filter 12 and the high-pass filter 13; the output end of the full-wave precision rectifying circuit 21 is connected with the output end of the full-wave precision rectifying module 2.
For example, referring to fig. 1, four full-wave precision rectifying circuits 21 are provided, and are respectively connected to one low-pass filter 11, two band-pass filters 12, and one high-pass filter 13.
Further, referring to fig. 3, which is a schematic structural diagram of a full-wave precision rectification circuit according to an embodiment of the present invention, the full-wave precision rectification circuit 21 includes a first operational amplifier U1, a second operational amplifier U2, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, a first diode D1, and a second diode D2;
the input end of the full-wave precision rectifying circuit 21 is connected with the first end of the first resistor R1;
the second end of the first resistor R1, the first end of the third resistor R3 and the cathode of the first diode D1 are connected with the inverting input end of the first operational amplifier U1, the non-inverting input end of the first operational amplifier U1 is connected with the ground through the second resistor R2, and the output end of the first operational amplifier U1 is connected with the cathode of the second diode D2;
a second end of the third resistor R3 is connected to the anode of the second diode D2, and the anode of the first diode D1 is connected to the output terminal of the first operational amplifier U1;
a first end of the fourth resistor R4 is connected to the anode of the second diode D2, a second end of the fourth resistor R4, a second end of the fifth resistor R5, and a first end of the seventh resistor R7 are connected to the inverting input terminal of the second operational amplifier U2, and a first end of the fifth resistor R5 is connected to the first end of the first resistor R1; the non-inverting input terminal of the second operational amplifier U2 is connected to ground through the sixth resistor R6; the output end of the second operational amplifier U2 is connected with the second end of the seventh resistor R7 and the output end of the full-wave precision rectifying circuit 21.
In this embodiment, as long as the input voltage signal causes a very slight change in the net input voltage of the integrated operational amplifier, the operating states of the two diodes can be changed, so that a weak ac voltage can be converted into a dc voltage for output, thereby achieving the purpose of precise rectification.
In a preferred embodiment, the integral comparison module 3 comprises at least four voltage integration circuits 31 and at least four voltage comparison circuits 32;
the output end of the voltage integrating circuit 31 is connected with the input end of the voltage comparing circuit 32, the input end of the voltage integrating circuit 31 is connected with the output end of the full-wave precision rectifying circuit 21 in a one-to-one correspondence manner, and the output end of the voltage comparing circuit 32 is connected with the signal output end V2.
For example, referring to fig. 1, four voltage integrating circuits 31 and four voltage comparing circuits 32 are provided, the input ends of the voltage integrating circuits 31 are correspondingly connected to the output ends of the four full-wave precision rectifying circuits 21, and the output end of the voltage comparing circuit 32 outputs a start harmonic wave recording signal.
Further, referring to fig. 4, which is a schematic structural diagram of a voltage integrating circuit according to an embodiment of the present invention, the voltage integrating circuit 31 includes a third operational amplifier U3, an eighth resistor R8, a ninth resistor R9, and a first capacitor C1;
a signal input terminal U of the voltage integrating circuit 31INThe negative input end of the third operational amplifier U3 is connected with the eighth resistor R8, and the positive input end of the third operational amplifier U3 is grounded through the ninth resistor R9;
the first end of the first capacitor C1 is connected to the inverting input terminal of the third operational amplifier U3, and the output terminal of the third operational amplifier U3 is connected to the second end of the first capacitor C1 and the signal output terminal of the voltage integrating circuit 31.
In this embodiment, the value of the output voltage of the voltage integrating circuit 31 is an integral value of the input voltage signal within a certain time period, that is, the full-wave rectified voltage signal output by the full-wave precise rectifying circuit 21 can be converted into an effective voltage value for output, so as to facilitate comparison with a reference voltage.
Further, referring to fig. 5, which is a schematic structural diagram of a voltage comparison circuit according to an embodiment of the present invention, the voltage comparison circuit 32 includes a fourth operational amplifier U4, a tenth resistor R10, an eleventh resistor R11, and a twelfth resistor R12;
an inverting input of the fourth operational amplifier U4Terminal and reference voltage input terminal U of the voltage comparison circuit 31REFA non-inverting input terminal of the fourth operational amplifier U4 is connected to the signal input terminal of the voltage comparison circuit 32; a power input end of the fourth operational amplifier U4 is connected to an external power VCC and a first end of the twelfth resistor R12, and an output end of the fourth operational amplifier U4 is connected to a second end of the twelfth resistor R12 and a signal output end of the voltage comparison circuit 32.
In this embodiment, the voltage comparison circuit 32 compares the reference voltage UREFWhen the effective value of the harmonic voltage is larger than the reference voltage U, the amplitude of the input signal is equal to the effective value of the harmonic voltage in the frequency bandREFWhen the signal is positive, a positive voltage signal is output, and when the signal is negative, a negative voltage signal is output. When the voltage comparison circuit 32 outputs a positive voltage signal, it indicates that the magnitude of the effective value of the harmonic voltage in the frequency band in the time period exceeds the specified limit, and the waveform of the voltage signal at the time needs to be recorded, so as to facilitate the analysis and processing of the harmonic, and then the start harmonic recording signal is output to start the harmonic recording. In this circuit, a reference voltage UREFCan be adjusted by an external processor and can be changed according to the actual condition of the power grid in operation. For example, if only one frequency band of 4 sub-frequency bands in the full frequency band is concerned, a higher reference voltage is set for the rest frequency bands, and a reasonable reference voltage is set for the frequency band to be concerned according to the actual requirement.
Preferably, the first operational amplifier U1, the second operational amplifier U2, the third operational amplifier U3, and the fourth operational amplifier U4 are OP285 operational amplifiers.
The main technical parameters of the operational amplifier OP285 are as follows:
(1) the operational amplifier OP285 is a precision high speed amplifier, which uses the front end of the Butler amplifier to combine the precision and low noise performance of the bipolar transistor with the speed of the JFET, and can produce an amplifier with high slew rate, low offset and good noise performance at low supply current.
(2) The circuit can realize circuits such as an instrument amplifier, a ramp generator, a double-quadrupole filter, a direct-current coupling audio system and the like, and can be used for surface mounting packaging of an 8-pin SOIC _ N.
(3) The low-voltage power supply has a low offset voltage of 250 mu V, low noise of 6 nV/V Hz, a distortion rate of less than or equal to 0.0006 percent, a high-voltage swing rate of 22V/mu s, a wide bandwidth of 9MHz, a low power supply current of 5mA, a low offset current of 2nA and stable unit gain.
While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention.

Claims (9)

1. A multiband harmonic wave recording starting circuit is characterized in that the multiband harmonic wave recording starting circuit is provided with a signal input end for inputting analog quantity voltage signals of different frequency bands in a power grid and a signal output end for outputting starting harmonic wave recording signals;
the multiband harmonic wave recording starting circuit comprises a filter module, a full-wave precision rectifying module and an integral comparison module; the signal input end is connected with the input end of the filter module, the output end of the filter module is connected with the input end of the full-wave precise rectification module, the output end of the full-wave precise rectification module is connected with the input end of the integral comparison module, and the output end of the integral comparison module is connected with the signal output end.
2. The multiband harmonic recording start circuit according to claim 1, wherein the filter module is composed of at least one low-pass filter, at least two band-pass filters, and at least one high-pass filter;
the signal input end is connected with the input ends of the low-pass filter, the band-pass filter and the high-pass filter, and the output ends of the low-pass filter, the band-pass filter and the high-pass filter are connected with the output end of the filter module.
3. The multiband harmonic recording start circuit according to claim 2, wherein the full-wave precision rectification module comprises at least four full-wave precision rectification circuits;
the input end of the full-wave precise rectifying circuit is connected with the output ends of the low-pass filter, the band-pass filter and the high-pass filter in a one-to-one correspondence manner; and the output end of the full-wave precise rectification circuit is connected with the output end of the full-wave precise rectification module.
4. The multiband harmonic recording start circuit according to claim 3, wherein the integral comparison module comprises at least four voltage integration circuits and at least four voltage comparison circuits;
the output end of the voltage integrating circuit is connected with the input end of the voltage comparing circuit, the input end of the voltage integrating circuit is connected with the output end of the full-wave precision rectifying circuit in a one-to-one correspondence mode, and the output end of the voltage comparing circuit is connected with the signal output end.
5. The multiband harmonic recording start circuit of claim 3, wherein the low pass filter is an LTC1069-1 low pass switched capacitor filter, the band pass filter is an LTC1067 common switched capacitor filter, and the high pass filter is an LTC-1067-50 common switched capacitor filter.
6. The multiband harmonic recording start circuit according to claim 3, wherein the full-wave precision rectification circuit comprises a first operational amplifier, a second operational amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, a first diode, and a second diode;
the input end of the full-wave precision rectifying circuit is connected with the first end of the first resistor;
the second end of the first resistor, the first end of the third resistor and the cathode of the first diode are connected with the inverting input end of the first operational amplifier, the non-inverting input end of the first operational amplifier is grounded through the second resistor, and the output end of the first operational amplifier is connected with the cathode of the second diode;
the second end of the third resistor is connected with the anode of the second diode, and the anode of the first diode is connected with the output end of the first operational amplifier;
a first end of the fourth resistor is connected with the anode of the second diode, a second end of the fourth resistor, a second end of the fifth resistor and a first end of the seventh resistor are connected with the inverting input end of the second operational amplifier, and a first end of the fifth resistor is connected with a first end of the first resistor; the positive phase input end of the second operational amplifier is grounded through the sixth resistor; and the output end of the second operational amplifier is connected with the second end of the seventh resistor and the output end of the full-wave precision rectifying circuit.
7. The multiband harmonic recording start circuit according to claim 4, wherein the voltage integration circuit comprises a third operational amplifier, an eighth resistor, a ninth resistor, and a first capacitor;
a signal input end of the voltage integrating circuit is connected with an inverting input end of the third operational amplifier through the eighth resistor, and a non-inverting input end of the third operational amplifier is grounded through the ninth resistor;
the first end of the first capacitor is connected with the inverting input end of the third operational amplifier, and the output end of the third operational amplifier is connected with the second end of the first capacitor and the signal output end of the voltage integrating circuit.
8. The multiband harmonic recording start circuit according to claim 4, wherein the voltage comparison circuit includes a fourth operational amplifier, a tenth resistor, an eleventh resistor, and a twelfth resistor;
the inverting input end of the fourth operational amplifier is connected with the reference voltage input end of the voltage comparison circuit, and the non-inverting input end of the fourth operational amplifier is connected with the signal input end of the voltage comparison circuit; and a power supply input end of the fourth operational amplifier is connected with an external power supply and a first end of the twelfth resistor, and an output end of the fourth operational amplifier is connected with a second end of the twelfth resistor and a signal output end of the voltage comparison circuit.
9. The multiband harmonic recording start circuit according to any one of claims 6 to 8, wherein the first operational amplifier, the second operational amplifier, the third operational amplifier and the fourth operational amplifier are OP285 operational amplifiers.
CN202010373409.3A 2020-05-06 2020-05-06 Multiband harmonic wave recording starting circuit Pending CN111628642A (en)

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Application Number Priority Date Filing Date Title
CN202010373409.3A CN111628642A (en) 2020-05-06 2020-05-06 Multiband harmonic wave recording starting circuit

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CN111628642A true CN111628642A (en) 2020-09-04

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