CN213181769U - Voltage harmonic sampling circuit with fourth-order high-pass filtering function for electric energy quality device - Google Patents
Voltage harmonic sampling circuit with fourth-order high-pass filtering function for electric energy quality device Download PDFInfo
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- CN213181769U CN213181769U CN202022261641.6U CN202022261641U CN213181769U CN 213181769 U CN213181769 U CN 213181769U CN 202022261641 U CN202022261641 U CN 202022261641U CN 213181769 U CN213181769 U CN 213181769U
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Abstract
The application provides a voltage harmonic sampling circuit with a fourth-order high-pass filtering function for an electric energy quality device, which comprises a positive circuit input end, a negative circuit input end, a front-end differential amplification circuit, a first-stage second-order high-pass filtering circuit, a second-stage second-order high-pass filtering circuit and a circuit output end; the positive circuit input end and the negative circuit input end are both connected with the front-end differential amplifier circuit; the front-end differential amplification circuit, the first-stage second-order high-pass filter circuit, the second-stage second-order high-pass filter circuit and the circuit output end are sequentially connected; the device is applied to an electric energy quality device by adopting a plurality of resistors, capacitors and operational amplifiers to be connected in a combined manner; the signals sequentially pass through the front-end differential amplification circuit, the first-stage second-order high-pass filter circuit, the second-stage second-order high-pass filter circuit and the circuit output end, and unnecessary low-order harmonic signals are filtered out through amplification and conditioning, so that only required high-frequency harmonic signals pass through, interference is reduced, and the sampling result is more accurate and reliable.
Description
Technical Field
The application relates to the technical field of electric energy quality devices, in particular to a voltage harmonic sampling circuit with a four-order high-pass filtering function for an electric energy quality device.
Background
The electric energy quality device is used for measuring and analyzing the influence of various electric equipment on the electric energy quality of the public power grid in different running states; the method is also used for measuring and analyzing the quality of the alternating current electric energy supplied to a user receiving end by the public power grid, wherein the indexes of measurement and analysis comprise power supply frequency deviation, power supply voltage fluctuation and flicker, allowable unbalance degree of power supply three-phase voltage, power grid harmonic waves and harmonic waves of non-stationary time-varying signals measured and analyzed by applying wavelet transformation.
The quality of the electric energy refers to the quality of the electric energy in the electric power system. At present, ultra-high harmonic is a new electric energy quality problem generated under the development trend of power electronics of a power system. With the rapid increase of the content of ultra-high order harmonics in the system, the attention, research and solution to the new power quality problem become more important. When the power quality device is used for monitoring the power quality in a power grid, because the power grid belongs to an industrial environment and an Electromagnetic Compatibility (EMC) environment is complex, it is important to accurately measure the content of higher harmonics in the power grid.
SUMMERY OF THE UTILITY MODEL
In order to solve the problems, the application provides a voltage harmonic sampling circuit with a fourth-order high-pass filtering function for an electric energy quality device, so that the problems of filtering out unnecessary low-order harmonic signals and accurately measuring higher harmonics are solved, and the sampled harmonic signals are more accurate and reliable.
In order to achieve the purpose, the application is realized by the following technical scheme: a voltage harmonic sampling circuit with a fourth-order high-pass filtering function for an electric energy quality device comprises a circuit positive input end, a circuit negative input end, a front-end differential amplification circuit, a first-stage second-order high-pass filtering circuit, a second-stage second-order high-pass filtering circuit and a circuit output end;
the positive circuit input end and the negative circuit input end are both connected with the front-end differential amplifier circuit;
the front-end differential amplification circuit, the first-stage second-order high-pass filter circuit, the second-stage second-order high-pass filter circuit and the circuit output end are connected in sequence.
Optionally, the front-end differential amplifier circuit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a first capacitor, a second capacitor, and a first operational amplifier;
one end of the first resistor is connected with the negative input end of the circuit, one end of the second resistor is connected with the positive input end of the circuit, the other end of the first resistor, one end of the third resistor and one end of the first capacitor are connected with the negative input end of the first operational amplifier, the other end of the second resistor, one end of the fourth resistor and one end of the second capacitor are connected with the positive input end of the first operational amplifier, the other end of the fourth resistor and the other end of the second capacitor are grounded, and the other end of the third resistor and the other end of the first capacitor are connected with the output end of the first operational amplifier;
and the output end of the first operational amplifier is connected with the first-stage second-order high-pass filter circuit.
Optionally, in the front-end differential amplifier circuit, the first resistor is equal to the second resistor, the third resistor is equal to the fourth resistor, and the first capacitor is equal to the second capacitor, so that a relationship between the input voltage and the output voltage is as follows:
wherein, V0To output a voltage, VinFor the input voltage, R3 is the third resistor and R1 is the first resistor.
Optionally, the positive input end of the first operational amplifier is powered by a +5V power supply, and the negative input end of the first operational amplifier is powered by a-5V power supply;
the model of the first operational amplifier is LMV842 MAX.
Optionally, the first-stage second-order high-pass filter circuit includes a fifth resistor, a sixth resistor, a third capacitor, a fourth capacitor, and a second operational amplifier;
one end of the third capacitor is connected with the front-end differential amplifier circuit, the other end of the third capacitor and one end of a fifth resistor are connected with one end of the fourth capacitor, the other end of the fourth capacitor and one end of a sixth resistor are connected with the positive input end of the second operational amplifier, the other end of the sixth resistor is grounded, and the other end of the fifth resistor and the negative input end of the second operational amplifier are connected with the output end of the second operational amplifier;
and the output end of the second operational amplifier is connected with the second-stage second-order high-pass filter circuit.
Optionally, the positive input end of the second operational amplifier is powered by a +5V power supply, and the negative input end of the second operational amplifier is powered by a-5V power supply;
the model of the second operational amplifier is LMV842 MAX.
Optionally, the second-stage second-order high-pass filter circuit includes a seventh resistor, an eighth resistor, a fifth capacitor, a sixth capacitor, and a third operational amplifier;
one end of the fifth capacitor is connected with the first-stage second-order high-pass filter circuit, the other end of the fifth capacitor and one end of a seventh resistor are connected with one end of the sixth capacitor, the other end of the sixth capacitor and one end of an eighth resistor are connected with the positive input end of the third operational amplifier, the other end of the eighth resistor is grounded, and the other end of the seventh resistor and the negative input end of the third operational amplifier are connected with the output end of the third operational amplifier;
and the output end of the third operational amplifier is connected with the output end of the circuit.
Optionally, the positive input end of the third operational amplifier is powered by a +5V power supply, and the negative input end of the third operational amplifier is powered by a-5V power supply;
the model of the third operational amplifier is LMV842 MAX.
According to the technical scheme, the voltage harmonic sampling circuit with the fourth-order high-pass filtering function for the electric energy quality device comprises a circuit positive input end, a circuit negative input end, a front-end differential amplification circuit, a first-stage second-order high-pass filtering circuit, a second-stage second-order high-pass filtering circuit and a circuit output end; the positive circuit input end and the negative circuit input end are both connected with the front-end differential amplifier circuit; the front-end differential amplification circuit, the first-stage second-order high-pass filter circuit, the second-stage second-order high-pass filter circuit and the circuit output end are sequentially connected; the method is applied to the electric energy quality device by adopting a plurality of resistors, capacitors and operational amplifiers to be combined and connected together; the signals sequentially pass through the front-end differential amplification circuit, the first-stage second-order high-pass filter circuit, the second-stage second-order high-pass filter circuit and the circuit output end, and unnecessary low-order harmonic signals are filtered out through amplification and conditioning, so that only required high-frequency harmonic signals pass through, interference is reduced, and the sampling result is more accurate and reliable.
Drawings
In order to more clearly explain the technical solution of the present application, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious to those skilled in the art that other drawings can be obtained according to the drawings without any creative effort.
Fig. 1 is a schematic diagram of a voltage harmonic sampling circuit with a fourth-order high-pass filtering function of an electric energy quality device according to an embodiment of the present application.
The device comprises a front-end differential amplification circuit 1, a first-stage second-order high-pass filter circuit 2 and a second-stage second-order high-pass filter circuit 3.
Detailed Description
In order to make the technical means, the creation features, the achievement purposes and the effects of the application easy to understand, the application is further described in the following with the specific embodiments.
Fig. 1 is a schematic diagram of a voltage harmonic sampling circuit with a fourth-order high-pass filtering function of an electric energy quality device In an embodiment of the present application, and as shown In fig. 1, the voltage harmonic sampling circuit with the fourth-order high-pass filtering function of the electric energy quality device is applied to the electric energy quality device, and has the fourth-order high-pass filtering function, and includes a circuit positive input end In +, a circuit negative input end In-, a front-end differential amplification circuit 1, a first-stage second-order high-pass filtering circuit 2, a second-stage second-order high-pass filtering circuit 3, and a circuit output end Out; the positive circuit input end In + and the negative circuit input end In-are both connected with the front-end differential amplifier circuit 1; the front-end differential amplification circuit 1, the first-stage second-order high-pass filter circuit 2, the second-stage second-order high-pass filter circuit 3 and the circuit output end Out are connected in sequence.
Signals enter from the positive input end In + of the circuit and the negative input end In-, and then sequentially pass through the front-end differential amplification circuit 1, the first-stage second-order high-pass filter circuit 2, the second-stage second-order high-pass filter circuit 3 and the circuit output end Out, In the process, the signals are amplified and conditioned, low-frequency signals are filtered, and finally required high-frequency signals are obtained and output from the circuit output end Out.
In some embodiments, the front-end differential amplifying circuit 1 includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first capacitor C1, a second capacitor C2, and a first operational amplifier OP 1; the operational amplifier is a circuit unit with high amplification factor, and in an actual circuit, a feedback network is usually combined to form a certain functional module, so that the operational amplifier is an amplifier with a special coupling circuit and feedback. The front-end differential amplifier circuit 1 has signal amplification and signal modulation functions, and an original electrical signal at a transmitting end in a communication system usually has a very low frequency spectrum component, and is generally not suitable for being directly transmitted in a channel. Therefore, it is usually necessary to convert the original signal into a high-frequency signal whose frequency band is suitable for channel transmission, and this process is called signal modulation.
One end of the first resistor R1 is connected to the negative input end In-, one end of the second resistor R2 is connected to the positive input end In +, the other end of the first resistor R1, one end of the third resistor R3 and one end of the first capacitor C1 are connected to the negative input end of the first operational amplifier OP1, the other end of the second resistor R2, one end of the fourth resistor R4 and one end of the second capacitor C2 are connected to the positive input end of the first operational amplifier OP1, the other end of the fourth resistor R4 and the other end of the second capacitor C2 are grounded, and the other end of the third resistor R3 and the other end of the first capacitor C1 are connected to the output end of the first operational amplifier OP 1; the output end of the first operational amplifier OP1 is connected to the first-stage second-order high-pass filter circuit 2.
Signals enter the front-end differential amplification circuit 1 from the positive circuit input end In + and the negative circuit input end In-, and the amplified and modulated signals are transmitted from the output end of the first operational amplifier OP1 and the first-stage second-order high-pass filter circuit 2.
In some embodiments, in the front end differential amplifier circuit 1, the first resistor R1 is equal to the second resistor R2, the third resistor R3 is equal to the fourth resistor R4, and the first capacitor C1 is equal to the second capacitor C2, then the relationship between the input voltage and the output voltage is:
wherein, V0To output a voltage, VinFor the input voltage, R3 is the third resistor and R1 is the first resistor.
In some embodiments, the positive input of the first operational amplifier OP1 is powered by a +5V power supply, and the negative input of the first operational amplifier OP1 is powered by a-5V power supply; the first operational amplifier OP1 in this example is a model LMV842MAX manufactured by Texas Instruments (TI).
In some embodiments, the first-stage second-order high-pass filter circuit 2 includes a fifth resistor R5, a sixth resistor R6, a third capacitor C3, a fourth capacitor C4, and a second operational amplifier OP 2. The first-stage second-order high-pass filter circuit 2 has the functions of signal conditioning and high-pass filtering; signal conditioning is the conversion of an analog signal into a digital signal for data acquisition, process control, performing a computational display readout, or other purposes.
One end of the third capacitor C3 is connected to the front-end differential amplifier circuit 1, the other end of the third capacitor C3 and one end of the fifth resistor R5 are connected to one end of the fourth capacitor C4, the other end of the fourth capacitor C4 and one end of the sixth resistor R6 are connected to the positive input end of the second operational amplifier OP2, the other end of the sixth resistor R6 is grounded, and the other end of the fifth resistor R5 and the negative input end of the second operational amplifier OP2 are connected to the output end of the second operational amplifier OP 2; the output end of the second operational amplifier OP2 is connected to the second-stage second-order high-pass filter circuit 3.
The amplified and modulated signal is output by the front-end differential amplification circuit 1, enters the first-stage second-order high-pass filter circuit 2 through one end of the third capacitor C3, is subjected to high-pass filtering conditioning, and is output by the output end of the second operational amplifier OP2 and enters the second-stage second-order high-pass filter circuit 3.
In some embodiments, the positive input of the second operational amplifier OP2 is powered by a +5V power supply, and the negative input of the second operational amplifier OP2 is powered by a-5V power supply; the second operational amplifier OP2 is model LMV842MAX produced by Texas Instruments (TI).
In some embodiments, the second-stage second-order high-pass filter circuit 3 includes a seventh resistor R7, an eighth resistor R8, a fifth capacitor C5, a sixth capacitor C6, and a third operational amplifier OP 3; the second-stage second-order high-pass filter circuit 3 has the functions of signal conditioning and high-pass filtering.
One end of the fifth capacitor C5 is connected to the first-stage second-order high-pass filter circuit 2, the other end of the fifth capacitor C5 and one end of the seventh resistor R7 are connected to one end of the sixth capacitor C6, the other end of the sixth capacitor C6 and one end of the eighth resistor R8 are connected to the positive input end of the third operational amplifier OP3, the other end of the eighth resistor R8 is grounded, and the other end of the seventh resistor R7 and the negative input end of the third operational amplifier OP3 are connected to the output end of the third operational amplifier OP 3; the output terminal of the third operational amplifier OP3 is connected to the circuit output terminal Out.
The signal after the high-pass filtering conditioning is output by the first-stage second-order high-pass filter circuit 2, enters the second-stage second-order high-pass filter circuit 3 through one end of the fifth capacitor C5, is subjected to the high-pass filtering conditioning again, is output by the output end of the third operational amplifier OP3 after being subjected to the high-pass filtering conditioning twice, and finally the required high-frequency signal is output through the circuit output end Out.
In some embodiments, the positive input of the third operational amplifier OP3 is powered with a +5V power supply, and the negative input of the third operational amplifier OP3 is powered with a-5V power supply; the third operational amplifier OP3 is model LMV842MAX produced by Texas Instruments (TI).
According to the technical scheme, the voltage harmonic sampling circuit with the fourth-order high-pass filtering function for the electric energy quality device comprises a circuit positive input end In +, a circuit negative input end In-, a front-end differential amplification circuit 1, a first-stage second-order high-pass filtering circuit 2, a second-stage second-order high-pass filtering circuit 3 and a circuit output end Out; the positive circuit input end In + and the negative circuit input end In-are both connected with the front-end differential amplifier circuit 1; the front-end differential amplification circuit 1, the first-stage second-order high-pass filter circuit 2, the second-stage second-order high-pass filter circuit 3 and the circuit output end Out are connected in sequence. The method is applied to the electric energy quality device by adopting a plurality of resistors, capacitors and operational amplifiers to be combined and connected together; the signals sequentially pass through the front-end differential amplification circuit 1, the first-stage second-order high-pass filter circuit 2, the second-stage second-order high-pass filter circuit 3 and the circuit output end Out, and unnecessary low-order harmonic signals are filtered Out through amplification and conditioning, so that only required high-frequency harmonic signals pass through, interference is reduced, and a sampling result is more accurate and reliable.
The embodiments of the present application have been described in detail, but the description is only for the preferred embodiments of the present application and should not be construed as limiting the scope of the application. All equivalent changes and modifications made within the scope of the present application shall fall within the scope of the present application.
Claims (8)
1. A voltage harmonic sampling circuit with a fourth-order high-pass filtering function for an electric energy quality device is characterized by comprising a circuit positive input end, a circuit negative input end, a front-end differential amplification circuit, a first-stage second-order high-pass filtering circuit, a second-stage second-order high-pass filtering circuit and a circuit output end;
the positive circuit input end and the negative circuit input end are both connected with the front-end differential amplifier circuit;
the front-end differential amplification circuit, the first-stage second-order high-pass filter circuit, the second-stage second-order high-pass filter circuit and the circuit output end are connected in sequence.
2. The voltage harmonic sampling circuit with the fourth-order high-pass filtering function of the electric energy quality device as claimed in claim 1, wherein the front-end differential amplifying circuit comprises a first resistor, a second resistor, a third resistor, a fourth resistor, a first capacitor, a second capacitor and a first operational amplifier;
one end of the first resistor is connected with the negative input end of the circuit, one end of the second resistor is connected with the positive input end of the circuit, the other end of the first resistor, one end of the third resistor and one end of the first capacitor are connected with the negative input end of the first operational amplifier, the other end of the second resistor, one end of the fourth resistor and one end of the second capacitor are connected with the positive input end of the first operational amplifier, the other end of the fourth resistor and the other end of the second capacitor are grounded, and the other end of the third resistor and the other end of the first capacitor are connected with the output end of the first operational amplifier;
and the output end of the first operational amplifier is connected with the first-stage second-order high-pass filter circuit.
3. The voltage harmonic sampling circuit with the fourth-order high-pass filtering function of the power quality device according to claim 2, wherein in the front-end differential amplification circuit, the first resistor is equal to the second resistor, the third resistor is equal to the fourth resistor, and the first capacitor is equal to the second capacitor, then the relationship between the input voltage and the output voltage is:
wherein, V0To output a voltage, VinFor the input voltage, R3 is the third resistor and R1 is the first resistor.
4. The voltage harmonic sampling circuit with the fourth-order high-pass filtering function of the power quality device as claimed in claim 2, wherein the positive input terminal of the first operational amplifier is powered by a +5V power supply, and the negative input terminal of the first operational amplifier is powered by a-5V power supply;
the model of the first operational amplifier is LMV842 MAX.
5. The voltage harmonic sampling circuit with the fourth-order high-pass filtering function of the electric energy quality device is characterized in that the first-stage second-order high-pass filtering circuit comprises a fifth resistor, a sixth resistor, a third capacitor, a fourth capacitor and a second operational amplifier;
one end of the third capacitor is connected with the front-end differential amplifier circuit, the other end of the third capacitor and one end of a fifth resistor are connected with one end of the fourth capacitor, the other end of the fourth capacitor and one end of a sixth resistor are connected with the positive input end of the second operational amplifier, the other end of the sixth resistor is grounded, and the other end of the fifth resistor and the negative input end of the second operational amplifier are connected with the output end of the second operational amplifier;
and the output end of the second operational amplifier is connected with the second-stage second-order high-pass filter circuit.
6. The voltage harmonic sampling circuit with the fourth-order high-pass filtering function of the power quality device as claimed in claim 5, wherein the positive input terminal of the second operational amplifier is powered by a +5V power supply, and the negative input terminal of the second operational amplifier is powered by a-5V power supply;
the model of the second operational amplifier is LMV842 MAX.
7. The voltage harmonic sampling circuit with the fourth-order high-pass filtering function of the electric energy quality device is characterized in that the second-stage second-order high-pass filtering circuit comprises a seventh resistor, an eighth resistor, a fifth capacitor, a sixth capacitor and a third operational amplifier;
one end of the fifth capacitor is connected with the first-stage second-order high-pass filter circuit, the other end of the fifth capacitor and one end of a seventh resistor are connected with one end of the sixth capacitor, the other end of the sixth capacitor and one end of an eighth resistor are connected with the positive input end of the third operational amplifier, the other end of the eighth resistor is grounded, and the other end of the seventh resistor and the negative input end of the third operational amplifier are connected with the output end of the third operational amplifier;
and the output end of the third operational amplifier is connected with the output end of the circuit.
8. The voltage harmonic sampling circuit with the fourth-order high-pass filtering function of the power quality device as claimed in claim 7, wherein the positive input terminal of the third operational amplifier is powered by a +5V power supply, and the negative input terminal of the third operational amplifier is powered by a-5V power supply;
the model of the third operational amplifier is LMV842 MAX.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022261641.6U CN213181769U (en) | 2020-10-12 | 2020-10-12 | Voltage harmonic sampling circuit with fourth-order high-pass filtering function for electric energy quality device |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022261641.6U CN213181769U (en) | 2020-10-12 | 2020-10-12 | Voltage harmonic sampling circuit with fourth-order high-pass filtering function for electric energy quality device |
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| Publication Number | Publication Date |
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| CN213181769U true CN213181769U (en) | 2021-05-11 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202022261641.6U Active CN213181769U (en) | 2020-10-12 | 2020-10-12 | Voltage harmonic sampling circuit with fourth-order high-pass filtering function for electric energy quality device |
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