CN206818789U - A kind of inverter output current detects circuit - Google Patents
A kind of inverter output current detects circuit Download PDFInfo
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- CN206818789U CN206818789U CN201720544084.4U CN201720544084U CN206818789U CN 206818789 U CN206818789 U CN 206818789U CN 201720544084 U CN201720544084 U CN 201720544084U CN 206818789 U CN206818789 U CN 206818789U
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- circuit
- mcu
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- operational amplifier
- optical coupling
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- Measurement Of Current Or Voltage (AREA)
Abstract
The utility model discloses a kind of inverter output current to detect circuit, it includes optical coupling isolation circuit, amplifying circuit and unipolarity change-over circuit, analog to digital conversion circuit, MCU and digital display tube, the output end of the optical coupling isolation circuit is connected with amplifying circuit, unipolarity change-over circuit, analog to digital conversion circuit and MCU in turn, and the output end of the MCU is connected with the input of the digital display tube.The utility model realizes current measurement with isolation optocoupler, and for Hall, isolated amplifier detection current scheme has cost lower, the linearity is more preferably in measurement range, it is smaller by external magnetic field interference, and temperature coefficient influences more low advantage, can be widely applied in middle low power inverter.Using high cmrr isolation optocoupler, it is internally integrated current sense function, eliminates inspection leakage resistance, saves space for PCB layouts, global design is more compact, and structure is lighter and handier.The utility model is widely used in various current detection circuits.
Description
Technical field
It the utility model is related to electronic technology field, more particularly to a kind of inverter output current detection circuit.
Background technology
With the continuous development of Power Electronic Technique, especially semiconductor devices, which is constantly updated, regenerates, in motor driving and work
The application of the inverter such as industry frequency conversion field is also more and more wider.And the detection to output current phase and amplitude directly influences inverter
Performance, row current detection mode commonly used in the trade is detected using Hall current sensor at present.But Hall current sensor
Price is high, and PCB areas occupied are big, easily by environmental disturbances such as external magnetic field and temperature.
Utility model content
In order to solve the above-mentioned technical problem, the purpose of this utility model is to provide a kind of inversion simple in construction, inexpensive
Device output current detection circuit.
Technical scheme is used by the utility model：A kind of inverter output current detects circuit, it include optocoupler every
From circuit, amplifying circuit and unipolarity change-over circuit, analog to digital conversion circuit, MCU and digital display tube, the optical coupling isolation circuit
Output end be connected with amplifying circuit, unipolarity change-over circuit, analog to digital conversion circuit and MCU, the output end of the MCU in turn
It is connected with the input of the digital display tube, the pulse current isolation that inverter exports is converted into by the optical coupling isolation circuit
Bi-Directional Pulsed Voltage Technique signal, and export to the amplifying circuit；The amplifying circuit will isolate the bipolar pulse after changing
Voltage signal amplifies, and exports to unipolarity change-over circuit, and the unipolarity change-over circuit is the bipolar pulse electricity after amplification
Pressure signal is converted into unipolar pulse signal, exports to MCU, MCU controls charactron real-time display by analog to digital conversion circuit
The pulse current size that the optical coupling isolation circuit exports inverter.
Further, the optical coupling isolation circuit includes high cmrr isolation optocoupler, the high cmrr isolation
Optocoupler is internally integrated Hall linear current sensing IC, its model ACS712ELCTR-20A-T.
Further, the unipolarity change-over circuit includes the first operational amplifier, first resistor, second resistance and the 3rd
Resistance, the output end of the amplifying circuit are connected by first resistor with the positive input of first operational amplifier, institute
The reverse input end for stating the first operational amplifier is connected to ground by second resistance, the output end of first operational amplifier with
The input connection of analog-digital conversion circuit as described, one end of the 3rd resistor and the opposite direction of first operational amplifier are defeated
Enter end connection, the other end is connected with the output end of first operational amplifier.
Further, the unipolarity change-over circuit also includes the first feedback capacity, first feedback capacity and described the
Three resistor coupled in parallel.
Further, it also includes low-pass filter circuit, and the input of the low-pass filter circuit is changed with the unipolarity
The output end connection of circuit, its output end are connected with analog-digital conversion circuit as described.
Further, it also includes voltage clamp circuit, and the voltage clamp circuit is used for the input of analog to digital conversion circuit
Terminal voltage clamper is in the range of safe voltage.
The beneficial effects of the utility model are：The utility model realizes current measurement with isolation optocoupler, compared to Hall
Speech, isolated amplifier detection current scheme have cost lower, and the linearity more preferably, is disturbed more by external magnetic field in measurement range
It is small, and temperature coefficient influences more low advantage, can be widely applied in middle low power inverter.
In addition, the utility model uses high cmrr isolation optocoupler, it is internally integrated current sense function, eliminates
Leakage resistance is examined, saves space for PCB layouts, global design is more compact, and structure is lighter and handier.
Brief description of the drawings
Specific embodiment of the present utility model is described further below in conjunction with the accompanying drawings：
Fig. 1 is the circuit block diagram of the specific embodiment of the utility model one；
Fig. 2 is the circuit theory diagrams of optical coupling isolation circuit and amplifying circuit in the specific embodiment of the utility model one.
Fig. 3 is unipolarity change-over circuit, low-pass filter circuit and voltage clamping in the specific embodiment of the utility model one
The schematic diagram of circuit.
Embodiment
It should be noted that in the case where not conflicting, the feature in embodiment and embodiment in the application can phase
Mutually combination.
As shown in figure 1, a kind of inverter output current detection circuit, it includes optical coupling isolation circuit, amplifying circuit and list
Polarity switching, analog to digital conversion circuit, MCU and digital display tube, the output end of the optical coupling isolation circuit are connected with turn
Amplifying circuit, unipolarity change-over circuit, analog to digital conversion circuit and MCU, the output end of the MCU and the digital display tube
Input is connected, and the pulse current isolation that inverter exports is converted into Bi-Directional Pulsed Voltage Technique by the optical coupling isolation circuit to be believed
Number, and export to the amplifying circuit；The amplifying circuit amplifies the Bi-Directional Pulsed Voltage Technique signal after changing is isolated, and defeated
Go out to unipolarity change-over circuit, the unipolarity change-over circuit and the Bi-Directional Pulsed Voltage Technique signal after amplification is converted into unipolarity
Pulse signal, exported by analog to digital conversion circuit to MCU, MCU controls charactron real-time display goes out the optical coupling isolation circuit will
The pulse current size of inverter output.
The utility model realizes current measurement with isolation optocoupler, for Hall, isolated amplifier detection electric current side
Case has cost lower, and the linearity is more preferably, smaller by external magnetic field interference in measurement range, and temperature coefficient influence is more low excellent
Point, it can be widely applied in middle low power inverter.
Preferred embodiment is further used as, the optical coupling isolation circuit includes high cmrr isolation optocoupler, institute
State high cmrr isolation optocoupler and be internally integrated Hall linear current sensing IC, its model ACS712ELCTR-20A-T.Adopt
With high cmrr isolation optocoupler, it is internally integrated current sense function, eliminates inspection leakage resistance, is saved for PCB layouts
Space, global design is more compact, and structure is lighter and handier.
It is further used as preferred embodiment, the unipolarity change-over circuit also includes the first feedback capacity, and described
One feedback capacity is in parallel with the 3rd resistor, can be that low frequency increases with smothing filtering and suppression high frequency by setting feedback capacity
Benefit becomes big.
Preferred embodiment is further used as, it also includes low-pass filter circuit, the input of the low-pass filter circuit
End is connected with the output end of the unipolarity change-over circuit, and its output end is connected with analog-digital conversion circuit as described.
Preferred embodiment is further used as, it also includes voltage clamp circuit, and the voltage clamp circuit is used for will
The input terminal voltage clamper of analog to digital conversion circuit is in the range of safe voltage.
It is described below for the particular circuit configurations of modules, fully to illustrate that work of the present utility model is former
Reason and beneficial effect.
As shown in Fig. 2 the optical coupling isolation circuit includes isolation optocoupler U20, the isolation optocoupler is internally integrated Hall line
Property current sensor, its model ACS712ELCTR-20A-T.The amplification path includes operational amplifier U21B, feedback resistance
R234, feedback capacity C95, resistance R233, resistance R232, resistance R236, resistance R235, the output of the isolation optocoupler U15
VIOUT, it is connected by resistance R233 with operational amplifier U21B positive input, the direction of the operational amplifier U21B is defeated
Enter end to be connected with positive level 2.5V by resistance R232, described feedback resistance R234 one end is reverse with the operational amplifier
Input is connected, and the other end is connected with its output end, forms backfeed loop.The feedback capacity C95 and the feedback resistance
R232 is in parallel, and the output end of the operational amplifier U21B is connected by the input of resistance R236 and the unipolarity change-over circuit
Connect, the positive input of the operational amplifier U21B is connected to ground by resistance R235.
Operation principle：Inverter three-phase exports U, V, W, and U phase output current sample circuits are shown in figure.0~20A (RMS)
1,2 pin of the electric current through isolation optocoupler U20 flow into, and 3,4 pin outflow, isolation optocoupler U15 realizes 2.1kV (RMS) electrical isolation, 7 pin
Output voltage signal, its amplitude and optocoupler primary current corresponding relation are 100mV/A, then amplify through amplifier amplifier U21B and change
Iu is -10.5V~+10.5V voltage signals.Resistance R234, resistance R235 resistance acquisition different amplification are adjusted, to meet
Different capacity grade driver (mainly including 0.7kw~2.2kw here) designs, very convenient.
As shown in figure 3, the unipolarity change-over circuit include the first operational amplifier U9B, first resistor, second resistance with
And 3rd resistor R28, wherein the first resistor includes resistance R47, resistance R195, resistance R47 connects with resistance R195, described
Second resistance includes resistance R27, resistance R194, and resistance R27 connects with resistance R194, and voltage signal Iu is by resistance R47, resistance
R195 is connected with the first operational amplifier U9B positive input, and the first operational amplifier U9B passes through resistance R27 and electricity
Resistance R194 is connected to ground, and one end of the 3rd resistor R28 is connected with the direction input of the first operational amplifier U9B,
The other end is connected with the output end of the first operational amplifier U9B.The low-pass filter circuit includes resistance R49, electric capacity
C40, the voltage clamp circuit include clamp diode D33, the first operational amplifier U9B and connected by resistance R49 and MCU
Connect, wherein MCU can be single-chip microcomputer, DSP etc. to be integrated with analog to digital conversion circuit.
It is in parallel with the 3rd resistor R28 that it also includes the first feedback capacity C38, the first feedback capacity C38.
Operation principle：- 10.5V~+10.5V voltage signals Iu is converted into 0~3V voltage signal AI-Iu through unipolarity, enters
Enter MCU analog quantity input, then actual output current can be gone out by LED charactrons real-time display after MCU calculation process
Virtual value size.R49, C40 form low-pass first order filter, reduce high-frequency signal interference, strengthen circuit stability.D33 will believe
Number AI-Iu clampers shield within 0~3V to MCU analog ports.
Above is preferably implement to be illustrated to of the present utility model, but the invention is not limited to the reality
Example is applied, those skilled in the art can also make a variety of equivalent changes on the premise of without prejudice to the utility model spirit
Shape or replacement, these equivalent deformations or replacement are all contained in the application claim limited range.
Claims (6)
1. a kind of inverter output current detects circuit, it is characterised in that：It includes optical coupling isolation circuit, amplifying circuit and monopole
Property change-over circuit, analog to digital conversion circuit, MCU and digital display tube, the output end of the optical coupling isolation circuit, which is connected with turn, puts
Big circuit, unipolarity change-over circuit, analog to digital conversion circuit and MCU, the output end of the MCU are defeated with the digital display tube
Enter end connection,
The pulse current isolation that inverter exports is converted into Bi-Directional Pulsed Voltage Technique signal by the optical coupling isolation circuit, and is exported
To the amplifying circuit；The amplifying circuit amplifies the Bi-Directional Pulsed Voltage Technique signal after changing is isolated, and exports to monopole
Property change-over circuit, the unipolarity change-over circuit the Bi-Directional Pulsed Voltage Technique signal after amplification be converted into unipolar pulse believe
Number, exported by analog to digital conversion circuit to MCU, MCU controls charactron real-time display and go out the optical coupling isolation circuit by inverter
The pulse current size of output.
2. inverter output current according to claim 1 detects circuit, it is characterised in that：The optical coupling isolation circuit bag
High cmrr isolation optocoupler is included, the high cmrr isolation optocoupler is internally integrated Hall linear current sensing IC, its
Model ACS712ELCTR-20A-T.
3. the inverter output current detection circuit according to any one of claim 1 or 2, it is characterised in that：The monopole
Property change-over circuit includes the first operational amplifier, first resistor, second resistance and 3rd resistor, the output of the amplifying circuit
End be connected by first resistor with the positive input of first operational amplifier, first operational amplifier it is reverse defeated
Enter end to be connected to ground by second resistance, the output end of first operational amplifier and the input of analog-digital conversion circuit as described
Connection, one end of the 3rd resistor is connected with the opposite direction input of first operational amplifier, the other end and described the
The output end connection of one operational amplifier.
4. inverter output current according to claim 3 detects circuit, it is characterised in that：The unipolarity change-over circuit
Also include the first feedback capacity, first feedback capacity is in parallel with the 3rd resistor.
5. inverter output current according to claim 4 detects circuit, it is characterised in that：It also includes LPF electricity
Road, the input of the low-pass filter circuit are connected with the output end of the unipolarity change-over circuit, its output end and the mould
Number change-over circuit connection.
6. inverter output current according to claim 5 detects circuit, it is characterised in that：It also includes voltage clamping electricity
Road, the voltage clamp circuit are used for the input terminal voltage clamper of analog to digital conversion circuit in the range of safe voltage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201720544084.4U CN206818789U (en) | 2017-05-16 | 2017-05-16 | A kind of inverter output current detects circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201720544084.4U CN206818789U (en) | 2017-05-16 | 2017-05-16 | A kind of inverter output current detects circuit |
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| Publication Number | Publication Date |
|---|---|
| CN206818789U true CN206818789U (en) | 2017-12-29 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201720544084.4U Expired - Fee Related CN206818789U (en) | 2017-05-16 | 2017-05-16 | A kind of inverter output current detects circuit |
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| Country | Link |
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| CN (1) | CN206818789U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109490794A (en) * | 2018-10-18 | 2019-03-19 | 湖南恩智测控技术有限公司 | A kind of power supply ripple test circuit and test method |
| CN110207841A (en) * | 2019-05-31 | 2019-09-06 | 广州致远电子有限公司 | Thermal resistance temperature surveying circuit and temperature measuring device |
-
2017
- 2017-05-16 CN CN201720544084.4U patent/CN206818789U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109490794A (en) * | 2018-10-18 | 2019-03-19 | 湖南恩智测控技术有限公司 | A kind of power supply ripple test circuit and test method |
| CN110207841A (en) * | 2019-05-31 | 2019-09-06 | 广州致远电子有限公司 | Thermal resistance temperature surveying circuit and temperature measuring device |
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| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20171229 Termination date: 20190516 |
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| CF01 | Termination of patent right due to non-payment of annual fee |