CN218445664U - High-precision multi-path small signal generating circuit - Google Patents
High-precision multi-path small signal generating circuit Download PDFInfo
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- CN218445664U CN218445664U CN202221499889.9U CN202221499889U CN218445664U CN 218445664 U CN218445664 U CN 218445664U CN 202221499889 U CN202221499889 U CN 202221499889U CN 218445664 U CN218445664 U CN 218445664U
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Abstract
The utility model relates to a high accuracy multichannel small-signal produces circuit. The problem of among the prior art tester can't directly be used for adopting the primary and secondary system that fuses of small-signal, adopt the transfer box to have bulky, inconvenient on-the-spot use, can't ensure small-signal amplitude precision and phase precision is solved. The circuit comprises an MCU unit, a digital-to-analog conversion unit, an analog-to-digital conversion unit and a range control unit, wherein the MCU unit is respectively connected with the digital-to-analog conversion unit and the analog-to-digital conversion unit, the digital-to-analog conversion unit comprises a plurality of output channels, each channel is connected to a signal output end after being respectively connected with the range control unit, the control end of the range control unit is connected to the MCU unit, and the analog-to-digital conversion unit comprises a plurality of input ends which are respectively correspondingly connected to the signal output ends. The utility model discloses can produce the secondary and fuse distribution terminal system small-signal, and output waveform signal satisfies amplitude precision and phase accuracy requirement to the small and exquisite light of distribution terminal tester that this circuit design goes out makes things convenient for the field application.
Description
Technical Field
The utility model belongs to the technical field of electric wire netting debugging equipment technique and specifically relates to a high accuracy multichannel small-signal produces circuit is related to.
Background
In the production debugging and field testing links of the distribution automation terminal, controllable voltage and current signals are required to be input into the distribution automation terminal, and whether the functions and the performance of the distribution automation terminal are normal or not is judged. This need is currently met primarily by relay protection testers or distribution terminal testers.
With the construction speed of the intelligent power grid, the investment of the power grid is inclined to the link of the power distribution network, primary and secondary fusion equipment tends to be large, and the bidding quantity of the circuit breakers on the primary and secondary fusion complete column is continuously increased in recent years. This requires that its corresponding test equipment follow up quickly. However, the existing tester is designed based on the traditional electromagnetic transformer terminal system, outputs large signals (current 0 to 5a and voltage 0 to 120v), and cannot be directly used for a primary-secondary fusion system adopting small signals (current 0 to 20v and voltage 0 to 3.25v).
At present, an inventor designs a transfer box, a traditional tester converts a large signal of the tester into a small signal for use after being connected with the transfer box, the method is really usable, but the transfer box is large and heavy in size, more in wiring and inconvenient to use on site, and the transfer box works in an open loop state, so that the amplitude precision and the phase precision of the small signal cannot be ensured.
Disclosure of Invention
The utility model discloses solve the unable problem that directly is used for adopting the primary and secondary fusion system of small signal of tester among the prior art, provide a high accuracy multichannel small signal production circuit.
The utility model discloses still solved current adoption transfer box and converted the large signal of tester into the small-signal use, had the bulky heavy of transfer box, inconvenient field usage, and can't ensure the problem of small-signal amplitude precision and phase precision, provided a high accuracy multichannel small-signal production circuit.
The above technical problem of the present invention can be solved by the following technical solutions: the utility model provides a high accuracy multichannel small-signal generating circuit, includes MCU unit, digital-to-analog conversion unit, analog-to-digital conversion unit, range control unit, the MCU unit links to each other with digital-to-analog conversion unit, analog-to-digital conversion unit respectively, digital-to-analog conversion unit includes a plurality of output channel, be connected to corresponding signal output part behind the range control unit is connected respectively to every passageway, range control unit control end is connected to the MCU unit, analog-to-digital conversion unit includes that a plurality of input correspond respectively to be connected to on the signal output part.
The utility model discloses the MCU unit is according to upper reaches interface parameter, produces the waveform data of each passageway, sends for digital analog conversion unit in proper order. The digital-to-analog conversion unit is used for digital-to-analog conversion and simultaneously establishing received waveform data. The range control unit controllably attenuates the output signal of the digital-to-analog conversion unit, and when a small-value signal needs to be output, the attenuation switch is started to form an attenuation circuit to attenuate the output signal of the digital-to-analog conversion unit to 1/N, so that the output of digital-to-analog conversion is improved, and the influence of the quantization error of the digital-to-analog conversion on the output signal is reduced; when a large-value signal needs to be output, the attenuation switch is switched off, the output signal of the digital-to-analog conversion unit is transmitted out as it is, the signal output end is provided with a plurality of corresponding output channels, and each output channel is connected with one signal output end. The analog-digital conversion unit recovers the output signal and sends the output signal to the MCU unit to determine whether the output signal meets the expected requirement, if the amplitude precision and the phase precision requirement cannot be met, the input data of the digital-analog conversion unit is finely adjusted to enable the final output waveform signal to meet the amplitude precision and the phase precision requirement, so that unexpected errors of the output signal are eliminated, if no output is caused by middle faults, or the output amplitude is insufficient due to rear-end overload, and the output reliability of the equipment is improved. Meanwhile, the signal precision is based on the sampling of the analog-digital conversion unit, and the requirement of precision components on an output signal channel is lowered. The utility model discloses can directly produce the small signal that once and twice fuses distribution terminal system, and ensured small signal amplitude precision and phase precision to the small and exquisite light of distribution terminal tester that this circuit design goes out makes things convenient for the field application.
As a preferred scheme, the range control unit includes a first resistor, a second resistor, and a first switch, one end of the first resistor is connected to the output channel of the digital-to-analog conversion unit, the other end of the first resistor is connected to the signal output terminal, one end of the second resistor is connected to the other end of the first resistor, the other end of the second resistor is connected to one end of the first switch, the other end of the first switch is grounded, and the control terminal of the first switch is connected to the MCU unit. In the scheme, the quantity control unit is connected to each output channel to controllably attenuate the output signal of the digital-to-analog conversion unit, and when a small-value signal needs to be output, the first switch is controlled to be closed, so that the output signal of the digital-to-analog conversion unit is attenuated to 1/N, the output of digital-to-analog conversion is improved, and the influence of the quantization error of the digital-to-analog conversion on the output signal is reduced; when a large-value signal needs to be output, the first switch is controlled to be switched off, and the output signal of the digital-to-analog conversion unit is transmitted out as it is.
As a preferable scheme, a low-pass filtering unit and a high-voltage amplifier unit are further connected between the range control unit and the signal output end in sequence. The low-pass filtering unit carries out filtering processing on the signal output by the range control unit, eliminates steps on the signal generated by digital-to-analog conversion and enables the waveform to be smooth. The smooth waveform signal after the filtering processing enters a high-voltage amplifier unit and is amplified to the amplitude which is finally needed.
Preferably, the digital-to-analog conversion unit and the analog-to-digital conversion unit are conversion units with synchronous start control. Because the data are transmitted to the digital-to-analog conversion unit, the data are in sequence, synchronous starting control is provided, and synchronous output of waveforms can be ensured. The analog-to-digital conversion units sample output signals in a rotating mode, phase difference exists among channels, and the analog-to-digital conversion units have a synchronous starting control function and can guarantee waveform synchronous sampling.
As a preferred scheme, the digital-to-analog conversion unit and the analog-to-digital conversion unit are both provided with parallel interfaces, and the digital-to-analog conversion unit and the analog-to-digital conversion unit are respectively connected with the parallel bus of the MCU unit through the parallel interfaces. The digital-to-analog conversion unit and the analog-to-digital conversion unit are provided with parallel interfaces, so that the data transmission speed is improved, the number of sampling points in one waveform is more, the sawtooth effect of the waveform is reduced, and the waveform deformation is smooth. And 16-bit resolution, the waveform precision is also improved.
As a preferable scheme, the digital-to-analog conversion circuit further comprises a reference voltage unit, and the reference voltage unit is connected with the digital-to-analog conversion unit. The reference voltage unit outputs reference voltage to the digital-to-analog conversion unit for providing reference, the precision requirement is better than 0.025%, and the temperature drift is lower than 2.5 ppm/DEG C. The stability of the generated waveform is increased by using the reference voltage as a reference.
As a preferred scheme, the high-voltage power supply unit is further included and comprises a plurality of different voltage output ends, and the high-voltage power supply unit is respectively connected with the MCU unit, the digital-to-analog conversion unit, the analog-to-digital conversion unit and the high-voltage amplifier unit. The high-voltage power supply generates 5V, positive and negative 15V and positive and negative 30V from an input power Vin through a push-pull circuit. A high voltage power supply provides electrical power to each cell.
As a preferred scheme, a sampling control unit is connected between the input end of the analog-to-digital conversion unit and the signal output end, the sampling control unit comprises a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a second switch and an amplifier, the positive input end of the amplifier is respectively connected with one end of the fifth resistor and one end of the sixth resistor, the other end of the fifth resistor is connected with the signal output end, the other end of the sixth resistor is grounded, the negative input end of the amplifier is respectively connected with one end of the third resistor and one end of the fourth resistor, the other end of the third resistor is connected with the output end of the amplifier, the other end of the fourth resistor is connected with one end of the second switch, the other end of the second switch is grounded, the output end of the amplifier is connected with the input end of the analog-to-digital conversion unit, and the control end of the second switch is connected with the MCU unit. The MCU unit controls the sampling control unit to work by controlling the second switch to be switched on and switched off, so that the input sampling signal is controlled.
Therefore, the utility model has the advantages that:
1. the small signal generating circuit is composed of the MCU unit, the digital-to-analog conversion unit, the analog-to-digital conversion unit and the range control unit, and can directly generate a small signal of a secondary fusion power distribution terminal system;
2. the signal of the signal output end is retrieved to determine whether the output signal meets the expected requirement, if the amplitude precision and the phase precision cannot be met, the input data of the digital-to-analog conversion unit is finely adjusted, so that the final output waveform signal meets the requirements of the amplitude precision and the phase precision, and the unexpected error of the output signal is also eliminated;
3. the power distribution terminal tester designed by the circuit is small, exquisite and portable, and is convenient for field application.
Drawings
Fig. 1 is a schematic diagram of a circuit structure of the present invention.
The device comprises a MCU unit 2, a digital-to-analog conversion unit 3, a range control unit 4, an analog-to-digital conversion unit 5, a low-pass filtering unit 6, a high-voltage amplifier unit 7, a reference voltage unit 8, a high-voltage power supply unit 9 and a sampling control unit.
Detailed Description
The technical solution of the present invention is further specifically described below by way of examples and with reference to the accompanying drawings.
Example (b):
the present embodiment of a high-precision multi-channel small signal generating circuit, as shown in fig. 1, includes an MCU unit 1, a digital-to-analog conversion unit 2, an analog-to-digital conversion unit 4, a range control unit 3, a low-pass filtering unit 5, a high-voltage amplifier unit 6, a reference voltage unit 7, a high-voltage power supply unit 8, and a sampling control unit 9. The MCU unit is respectively connected with the digital-to-analog conversion unit and the analog-to-digital conversion unit, the digital-to-analog conversion unit comprises a plurality of output channels, and each channel is respectively connected with the range control unit, the low-pass filtering unit, the high-voltage amplifier unit and the output switch in sequence and then connected to a signal output end. The control end of the range control unit is connected to the MCU unit, the analog-to-digital conversion unit comprises a plurality of input ends, and the input ends are respectively and correspondingly connected to a signal output end after being connected with the sampling control unit. The reference voltage unit is connected with the digital-to-analog conversion unit.
The MCU unit is provided with an external parallel bus, the digital-to-analog conversion unit and the analog-to-digital conversion unit are conversion units with synchronous starting control, the digital-to-analog conversion unit and the analog-to-digital conversion unit are both provided with parallel interfaces, the resolution ratio is 16 bits or more, and the digital-to-analog conversion unit and the analog-to-digital conversion unit are respectively connected with the MCU unit parallel bus through the parallel interfaces. The reference voltage unit provides reference for the digital-to-analog conversion unit, and the required precision is better than 0.025 percent, and the temperature drift is lower than 2.5 ppm/DEG C. And the MCU unit produces waveform data of each channel according to the upstream interface parameters and sequentially sends the waveform data to the digital-to-analog conversion unit. The data are transmitted to the digital-to-analog conversion unit, the sequencing exists, the synchronous starting control is realized, and the synchronous output of the waveforms can be ensured. The analog-to-digital conversion units sample output signals in a rotating mode, phase difference exists among channels, and the analog-to-digital conversion units have a synchronous starting control function and can guarantee waveform synchronous sampling. The digital-to-analog conversion unit and the analog-to-digital conversion unit are provided with parallel interfaces, so that the data transmission speed is improved, the number of sampling points in one waveform is more, the sawtooth effect of the waveform is reduced, and the waveform deformation is smooth. And 16-bit resolution, the waveform precision is also improved. The stability of the generated waveform is improved by using the required reference voltage as a reference.
The digital-to-analog conversion unit is initialized after starting to work, data of 4 channels are set respectively, then digital-to-analog conversion is started, data of the 4 channels which are continuously set are returned, and the digital-to-analog conversion is repeated. The analog-to-digital conversion unit recovers the output signal, starts analog-to-digital conversion and then sends the analog-to-digital conversion to the MCU unit to determine whether the output signal meets the expected requirement, and if the output signal does not meet the requirements of amplitude precision and phase precision, the final output waveform signal meets the requirements of the amplitude precision and the phase precision by finely adjusting input data of the digital-to-analog conversion unit, so that unexpected errors of the output signal, such as no output caused by middle faults or insufficient output amplitude caused by rear-end overload, are eliminated, and the output reliability of the equipment is improved. Meanwhile, the signal precision is based on the sampling of the analog-digital conversion unit, and the requirement of precision components on an output signal channel is lowered. The utility model discloses can directly produce the small-signal that once and twice fuses distribution terminal system, and ensured small-signal amplitude precision and phase precision
The range control unit comprises a first resistor R1, a second resistor R2 and a first switch K1, one end of the first resistor R1 is connected with an output channel of the digital-to-analog conversion unit, the other end of the first resistor R1 is connected to the signal output end, one end of the second resistor R2 is connected to the other end of the first resistor, the other end of the second resistor R2 is connected with one end of the first switch K1, the other end of the first switch K2 is grounded, and the control end of the first switch K1 is connected to the MCU unit. The range control unit controllably attenuates the output signal of the digital-to-analog conversion unit, and controls to close the first switch when a small-value signal needs to be output, so that the output signal of the digital-to-analog conversion unit is attenuated to 1/N, the output of digital-to-analog conversion is improved, and the influence of the quantization error of the digital-to-analog conversion on the output signal is reduced; when a large-value signal needs to be output, the first switch is controlled to be switched off, and the output signal of the digital-to-analog conversion unit is transmitted out as it is.
The sampling control unit comprises a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a second switch K2 and an amplifier, wherein the positive input end of the amplifier is respectively connected with one end of the fifth resistor R5, one end of the sixth resistor R6, the other end of the fifth resistor R5 is connected with the signal output end, the other end of the sixth resistor R6 is grounded, the negative input end of the amplifier is respectively connected with one end of the third resistor R3 and one end of the fourth resistor R4, the other end of the third resistor R3 is connected with the output end of the amplifier, the other end of the fourth resistor R4 is connected with one end of the second switch K2, the other end of the second switch K2 is grounded, the output end of the amplifier is connected with the input end of the analog-to-digital conversion unit, and the control end of the second switch K2 is connected with the MCU unit.
The high-voltage power supply unit comprises a plurality of different voltage output ends, and is respectively connected with the MCU unit, the digital-to-analog conversion unit, the analog-to-digital conversion unit and the high-voltage amplifier unit. The high-voltage power supply generates 5V, positive and negative 15V and positive and negative 30V from an input power Vin through a push-pull circuit. The high voltage amplifier unit needs to output an ac signal of up to 20V, and considering that the high voltage amplifier has a voltage drop of 1.5V, the high voltage power supply unit should not lower than 30V, and the 30V terminal of the high voltage power supply unit is connected to the high voltage amplifier.
The specific embodiments described herein are merely illustrative of the spirit of the invention. Various modifications, additions and substitutions for the specific embodiments described herein may be made by those skilled in the art without departing from the spirit of the invention or exceeding the scope of the invention as defined in the accompanying claims.
Although the terms MCU unit, digital-to-analog conversion unit, range control unit, analog-to-digital conversion unit, etc. are used more herein, the possibility of using other terms is not excluded. These terms are used merely to more conveniently describe and explain the nature of the present invention; they are to be construed in a manner that is inconsistent with the spirit of the invention.
Claims (8)
1. A high-precision multi-path small signal generating circuit is characterized in that: the device comprises an MCU unit, a digital-to-analog conversion unit, an analog-to-digital conversion unit and a range control unit, wherein the MCU unit is respectively connected with the digital-to-analog conversion unit and the analog-to-digital conversion unit, the digital-to-analog conversion unit comprises a plurality of output channels, each channel is connected to a corresponding signal output end after being respectively connected with the range control unit, the control end of the range control unit is connected to the MCU unit, and the analog-to-digital conversion unit comprises a plurality of input ends which are respectively and correspondingly connected to the signal output ends.
2. The high-precision multi-path small signal generating circuit as claimed in claim 1, wherein the range control unit includes a first resistor, a second resistor, and a first switch, one end of the first resistor is connected to the output channel of the digital-to-analog conversion unit, the other end of the first resistor is connected to the signal output terminal, one end of the second resistor is connected to the other end of the first resistor, the other end of the second resistor is connected to one end of the first switch, the other end of the first switch is grounded, and the control terminal of the first switch is connected to the MCU unit.
3. The high-precision multi-path small signal generating circuit as claimed in claim 1 or 2, wherein a low-pass filtering unit and a high-voltage amplifier unit are connected between the range control unit and the signal output end in sequence.
4. A high precision multi-path small signal generating circuit as claimed in claim 1 or 2, wherein said digital-to-analog converting unit and analog-to-digital converting unit are converting units with synchronous start control.
5. A high-precision multi-channel small signal generating circuit as claimed in claim 1 or 2, wherein the digital-to-analog converting unit and the analog-to-digital converting unit both have parallel interfaces, and the digital-to-analog converting unit and the analog-to-digital converting unit are respectively connected with the MCU unit parallel bus through the parallel interfaces.
6. A high accuracy multi-channel small signal generating circuit as defined in claim 3 further comprising a reference voltage unit, the reference voltage unit being connected to the digital-to-analog converting unit.
7. The high-precision multi-path small signal generating circuit as claimed in claim 6, further comprising a high voltage power supply unit, wherein the high voltage power supply unit comprises a plurality of different voltage output terminals, and the high voltage power supply unit is respectively connected to the MCU unit, the digital-to-analog conversion unit, the analog-to-digital conversion unit, and the high voltage amplifier unit.
8. The circuit for generating the high-precision multipath small signals according to claim 1 or 2, wherein a sampling control unit is connected between the input end and the signal output end of the analog-to-digital conversion unit, the sampling control unit comprises a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a second switch and an amplifier, the positive input end of the amplifier is respectively connected with one end of the fifth resistor and one end of the sixth resistor, the other end of the fifth resistor is connected with the signal output end, the other end of the sixth resistor is grounded, the negative input end of the amplifier is respectively connected with one end of the third resistor and one end of the fourth resistor, the other end of the third resistor is connected with the output end of the amplifier, the other end of the fourth resistor is connected with one end of the second switch, the other end of the second switch is grounded, the output end of the amplifier is connected with the input end of the analog-to-digital conversion unit, and the control end of the second switch is connected with the MCU unit.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202221499889.9U CN218445664U (en) | 2022-06-14 | 2022-06-14 | High-precision multi-path small signal generating circuit |
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| CN202221499889.9U CN218445664U (en) | 2022-06-14 | 2022-06-14 | High-precision multi-path small signal generating circuit |
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| CN218445664U true CN218445664U (en) | 2023-02-03 |
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| CN202221499889.9U Active CN218445664U (en) | 2022-06-14 | 2022-06-14 | High-precision multi-path small signal generating circuit |
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