CN213581134U - SVG inverter current sampling design circuit based on manganin shunt - Google Patents
SVG inverter current sampling design circuit based on manganin shunt Download PDFInfo
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- CN213581134U CN213581134U CN202020263108.0U CN202020263108U CN213581134U CN 213581134 U CN213581134 U CN 213581134U CN 202020263108 U CN202020263108 U CN 202020263108U CN 213581134 U CN213581134 U CN 213581134U
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- current sampling
- operational amplifier
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Abstract
The utility model discloses a SVG contravariant current sampling design circuit based on manganin shunt improves current SVG contravariant current sampling technique, will turn into the measurement to the manganin shunt both ends voltage of establishing ties to the measurement of contravariant current, has that the sampling effect is good, postpone low, isolation strength is high, occupy small, the overall arrangement is simple, advantage with low costs.
Description
Technical Field
The utility model relates to an electric energy quality administers the field, especially relates to a SVG inverter current sampling design circuit based on manganin shunt.
Background
SVG equipment is called low pressure static var generator again, is a kind of comprehensive reactive power compensator, through the real-time monitoring system current of external current transformer, and process the analysis to the system current information through the internal controller, in order to judge the real-time state of the system, calculate the negative sequence that needs to compensate when reaching the sine wave state, zero sequence each time current at the same time, then send the control signal to the inside IGBT and drive its action, send out the reactive, unbalanced and anti-harmonic current that compensation needs, and carry out sampling monitoring to the contravariant current of output, adjust the driving scheme of the inside IGBT in real time, in order to reach the accurate compensation purpose.
Because the effective value of the SVG inverter current is generally between dozens of A and hundreds of A, the signal frequency is generally above 10KHZ, the sampling frequency is more than 2 times of the inverter current signal frequency, and high-frequency common-mode interference exists in the inverter current. Therefore, the inverter current sampling circuit has the requirements of good heat dissipation, high bandwidth, high transient common mode immunity and strong and weak electrical isolation.
At present, current transformers or Hall sensors are mostly applied to domestic markets for current sampling, and the scheme has the advantages of simple circuit, large size, complex layout and high cost, and can basically meet the sampling requirement.
SUMMERY OF THE UTILITY MODEL
In order to solve the above problem, an object of the utility model is to provide a SVG inverter current sampling design circuit based on manganin shunt to solve the sampling scheme who uses hall sensor to give first place to among the prior art.
The utility model discloses constitute characterized by shunt, DC-DC power module, isolation fortune are put, second grade amplifier circuit, voltage bias circuit, main control chip: the design is applied to sampling of an inverter current in the SVG; the manganin shunt and the selected device have lower temperature drift and are low in temperature influence; the shunt is a manganin shunt, and the resistance value is generally in the order of m omega; the DC-DC power supply module outputs a plurality of paths of different direct-current voltages to supply power to the primary/secondary isolation operational amplifier, the post operational amplifier, the DSP and the voltage bias circuit; the isolation operational amplifier is an optical coupling isolation operational amplifier; the main control chip is a DSP and is used for sampling, analyzing, calculating and controlling the sampling signal and controlling the output current in real time.
The utility model discloses a SVG contravariant current sampling design circuit based on manganin shunt improves current SVG contravariant current sampling technique, will turn into the measurement to the manganin shunt both ends voltage of establishing ties to the measurement of contravariant current, has that the sampling effect is good, postpone low, isolation strength is high, occupy small, the overall arrangement is simple, advantage with low costs.
Drawings
FIG. 1 is a scheme of the SVG inverter current sampling design circuit based on the manganin shunt of the utility model;
fig. 2 is a DC-DC power module in the present invention.
Detailed Description
The following description will be made with reference to fig. 1 and 2 for further explanation of the present invention.
A SVG inverter current sampling design circuit based on a manganin shunt comprises a shunt, a DC-DC power supply module, an isolation operational amplifier, a secondary amplification circuit, a voltage bias circuit and a main control chip.
The manganin shunt has a fixed resistance value, and because the inversion current is generally large, the resistance value of hundreds of u omega or m omega is often selected and connected in series into the SVG inversion current loop, and when the SVG outputs the inversion current, a certain voltage drop is generated at two ends of the manganin shunt according to the magnitude of the inversion current; the voltage at two ends of the manganin shunt is input to the primary side of the isolation operational amplifier through differential wiring, and the isolated and amplified differential signal is output at the secondary side through the isolation and amplification effects of the isolation operational amplifier; differential signals output by the isolated operational amplifier enter a secondary amplifying circuit formed by a common operational amplifier, and single-ended voltage signals which accord with the acceptable range of the DSP are output finally under the combined action of a voltage biasing circuit, and are subjected to sampling, operation, processing and IGBT control by the DSP to carry out accurate compensation; and each part of devices realize power supply through different voltages output by the power supply module.
The above only is the embodiment of the present invention, not limiting the patent scope of the present invention, all the equivalent circuits or equivalent flow changes made in the specification and the attached drawings or directly or indirectly applied to other related technical fields are included in the patent protection scope of the present invention.
Claims (5)
1. The utility model provides a SVG inverter current sampling design circuit based on manganin shunt comprises shunt, DC-DC power module, isolation operational amplifier, second grade amplifier circuit, voltage bias circuit, main control chip, its characterized in that:
the inverter current sampling design circuit is connected in series into an SVG inverter current loop through a shunt, and converts a current signal into a differential voltage signal;
the inverter current sampling design circuit outputs a plurality of paths of different direct-current voltages to the primary/secondary isolation operational amplifier, the post operational amplifier, the DSP and the voltage bias circuit by the DC-DC power supply module to supply power;
in the inverter current sampling design circuit, a secondary amplification circuit amplifies a differential voltage signal output by an isolation operational amplifier for the second time, and simultaneously filters the signal and converts the signal into a single-ended signal;
the inverter current sampling design circuit integrally promotes single-ended signals output by the operational amplifier by the voltage bias circuit, so that analog signals input into the main control chip are matched with the upper and lower limits of acceptable input of the main control chip;
the inverter current sampling design circuit is used for sampling, operating and controlling the processed analog signals by the main control chip.
2. The SVG inverter current sampling design circuit based on manganin shunt according to claim 1, characterized in that said shunt is a manganin shunt.
3. The SVG inverter current sampling design circuit based on manganin shunt of claim 1, characterized in that said DC-DC power supply module outputs multiple different DC voltages to power the primary/secondary isolation operational amplifier, the post operational amplifier, DSP, voltage bias circuit.
4. The SVG inverter current sampling design circuit based on the manganin shunt according to claim 1, characterized in that said isolation operational amplifier is an optical coupling isolation operational amplifier.
5. The SVG inverter current sampling design circuit based on manganin shunt of claim 1, characterized by that, the main control chip is DSP, sampling, analyzing, calculating, controlling the sampling signal, real-time controlling the output current.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020263108.0U CN213581134U (en) | 2020-03-05 | 2020-03-05 | SVG inverter current sampling design circuit based on manganin shunt |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202020263108.0U CN213581134U (en) | 2020-03-05 | 2020-03-05 | SVG inverter current sampling design circuit based on manganin shunt |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN213581134U true CN213581134U (en) | 2021-06-29 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202020263108.0U Active CN213581134U (en) | 2020-03-05 | 2020-03-05 | SVG inverter current sampling design circuit based on manganin shunt |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN213581134U (en) |
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2020
- 2020-03-05 CN CN202020263108.0U patent/CN213581134U/en active Active
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