CN207649787U - A kind of motor temperature measuring circuit of band output isolation - Google Patents
A kind of motor temperature measuring circuit of band output isolation Download PDFInfo
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- CN207649787U CN207649787U CN201721545102.7U CN201721545102U CN207649787U CN 207649787 U CN207649787 U CN 207649787U CN 201721545102 U CN201721545102 U CN 201721545102U CN 207649787 U CN207649787 U CN 207649787U
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- operational amplifier
- resistance
- phase
- reverse side
- output
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Abstract
The utility model discloses a kind of motor temperature measuring circuits of band output isolation, including sequentially connected constant-current source output circuit, signal measurement filter circuit and output isolation circuit.The utility model measures the resistance value of platinum resistance PT100 sensors using the measurement method of three-wire system constant current source forcing, measures the operating temperature of motor indirectly, has effectively canceled out the error that connecting cable resistance band comes.The AD conversion function of electric power three phase metering chip is utilized in sampled data converter, not only ensure that the requirement of high-acruracy survey, but also greatly reduces cost.The USART mouth signal wires of three phase metering chip are realized by optocoupler with subsequent conditioning circuit and are isolated, have ensured the reliability and safety of protective device.
Description
Technical field
The utility model is related to motor technology fields, and more specifically, more particularly to a kind of band output is isolated electronic
Machine temperature measuring circuit.
Background technology
With the continuous development of automatic control technology and intelligence manufacture, threephase asynchronous has become major impetus
Source, electric current can be increased drastically when short circuit or earth fault occur for motor, and temperature also can be increased drastically therewith, if not being protected
Motor can be caused to burn, so being the most direct mode that motor carries out temperature protection to the temperature measurement of motor.
What motor temperature sensor was usually used now is platinum resistance PT100 sensors, directly in the form of probe
Inside motor body, if there is electric leakage or misconnection to forceful electric power circuit, protective device can be caused to burn, or even meeting
Cause fire.Motor live in actual use often from control room motor protecting device have it is far with a distance from, if hair
The high pressures signal cross-talks such as raw lightning stroke, can cause motor protecting device to damage, and keep the safety in production to influence, and prior art side
Case is mainly the scheme with linear optical coupling isolation, but the linear optical coupling linearity is less desirable to have deviation to need hardware calibration,
And it is expensive；Secondly when platinum resistance PT100 sensors are long with motor protecting device connection cables, cable resistance value
Influence whether measurement accuracy, mostly device cannot eliminate cable using two-wire system Wheatstone bridge detection circuit at present
The error brought.
Utility model content
The purpose of this utility model is to provide a kind of constant-current source Exciting-simulator system band lead-wire compensations, and are not required to the band of hardware calibration
Export the motor temperature measuring circuit of isolation.
In order to achieve the above object, the technical solution adopted in the utility model is as follows：
A kind of motor temperature measuring circuit of band output isolation, including sequentially connected constant-current source output circuit, signal
Measure filter circuit and output isolation circuit；
The constant-current source output circuit includes voltage stabilizing chip LM431, operational amplifier U2A, operational amplifier U2B, power supply
Cathode terminal of the anode through resistor R3 connection voltage stabilizing chips LM431, the control terminal of LM431 connect fortune with cathode terminal by resistance R5
The in-phase end of amplifier U2A is calculated, the output of operational amplifier U2B is connected after the in-phase end series resistance R4 of operational amplifier U2A
End, the output end and reverse side of operational amplifier U2A are connected with resistance R1, the reverse side series resistance R2 of operational amplifier U2A
After be grounded, the reverse side of operational amplifier U2B is connected with output end, the output end and operational amplifier U2B of operational amplifier U2A
In-phase end be connected with resistance Ref；
The signal measurement filter circuit includes operational amplifier U2C and operational amplifier U2D, sensor signal lines B1 strings
The reverse side of connection operational amplifier U2C after connection resistance R8, the reverse side and output end of operational amplifier U2C are connected with resistance
The in-phase end of R9, operational amplifier U2C connects sensor signal lines B2, the output end of operational amplifier U2C successively resistance R12 and
The in-phase end of operational amplifier U2D is connected after resistance R13, the in-phase end of operational amplifier U2D is also grounded by capacitance C10, is transported
It is grounded after calculating the reverse side series resistance R6 of amplifier U2D, operation is connected after the reverse side series resistance R7 of operational amplifier U2D
The output end of amplifier U2D；
The output isolation circuit includes three phase metering chip, crystal oscillator Y1, resistance, the capacitance composition of model HT7017,
Three phase metering chip the 12nd, 13 pins be connected with crystal oscillator Y1, the both ends of crystal oscillator Y1 are followed by by capacitance C9 and capacitance C10 respectively
Ground, the 2nd pin of the 10th pin connection optocoupler U3 of three phase metering chip, the 11st pin connection optocoupler U2 of three phase metering chip
The 2nd pin, be in series with pull-up resistor R38 between the 1st pin and isolated power supply 5V of optocoupler U3, the 1st pin of optocoupler U2 with
Pull-up resistor R34 is in series between isolated power supply 5V.
Compared with prior art, the utility model has the advantage of：The utility model utilizes three-wire system constant current source forcing
Measurement method measures the resistance value of platinum resistance PT100 sensors, measures the operating temperature of motor indirectly, has effectively canceled out even
Connect the error that cable resistance is brought.The AD conversion function of electric power three phase metering chip is utilized in sampled data converter, not only protects
The requirement of high-acruracy survey has been demonstrate,proved, and has greatly reduced cost.The USART mouth signal wires of three phase metering chip are passed through into optocoupler
It realizes and is isolated with subsequent conditioning circuit, ensured the reliability and safety of protective device.
Description of the drawings
In order to illustrate the embodiment of the utility model or the technical proposal in the existing technology more clearly, below will be to embodiment
Or attached drawing needed to be used in the description of the prior art is briefly described, it should be apparent that, the accompanying drawings in the following description is only
It is some embodiments of the utility model, for those of ordinary skill in the art, in the premise not made the creative labor
Under, other drawings may also be obtained based on these drawings.
Fig. 1 is the circuit diagram of the motor temperature measuring circuit of the utility model band output isolation.
Fig. 2 is the wiring diagram of output isolation circuit in the motor temperature measuring circuit that the output of the utility model band is isolated.
Fig. 3 is the equivalent circuit diagram of the motor temperature measuring circuit of the utility model band output isolation.
Specific implementation mode
The preferred embodiment of the utility model is described in detail below in conjunction with the accompanying drawings, so that the advantages of the utility model
It can be easier to be readily appreciated by one skilled in the art with feature, it is apparent clear to be made to the scope of protection of the utility model
Define.
As shown in fig.1, the utility model provides a kind of motor temperature measuring circuit of band output isolation, including successively
Constant-current source output circuit, signal measurement filter circuit and the output isolation circuit of connection.
The constant-current source output circuit includes voltage stabilizing chip LM431, operational amplifier U2A, operational amplifier U2B, power supply
Cathode terminal of the anode through resistor R3 connection voltage stabilizing chips LM431, the control terminal of LM431 connect fortune with cathode terminal by resistance R5
The in-phase end of amplifier U2A is calculated, the output of operational amplifier U2B is connected after the in-phase end series resistance R4 of operational amplifier U2A
End, the output end and reverse side of operational amplifier U2A are connected with resistance R1, the reverse side series resistance R2 of operational amplifier U2A
After be grounded, the reverse side of operational amplifier U2B is connected with output end, the output end and operational amplifier U2B of operational amplifier U2A
In-phase end be connected with resistance Ref.
Potential point in figureWhat operational amplifier U2A was constituted is in-phase proportion amplifying circuit,
It is Vx+2.5V that it, which is exported, realizes constant current output, Current calculation so understanding that the electric current of Ref is not influenced by current potential at Vx
Formula is as follows：
The resistance value of modification Ref known to above formula is the output current of changeable constant-current source.
The signal measurement filter circuit includes operational amplifier U2C and operational amplifier U2D, sensor signal lines B1 strings
The reverse side of connection operational amplifier U2C after connection resistance R8, the reverse side and output end of operational amplifier U2C are connected with resistance
The in-phase end of R9, operational amplifier U2C connects sensor signal lines B2, the output end of operational amplifier U2C successively resistance R12 and
The in-phase end of operational amplifier U2D is connected after resistance R13, the in-phase end of operational amplifier U2D is also grounded by capacitance C10, is transported
It is grounded after calculating the reverse side series resistance R6 of amplifier U2D, operation is connected after the reverse side series resistance R7 of operational amplifier U2D
The output end of amplifier U2D.
The operational amplification circuit that signal measurement filter circuit is made of U2C and U2D, equivalent circuit as shown in figure 3,
Rw1, Rw2, Rw3 are the equivalent resistance of 3 leads of sensor, the calculation shows that：
VB=VC=I × (RPT100+Rw3)；
VA=I × (Rw1+RPT100+Rw3)；
The output that operational amplifier can be obtained by superposition theorem is：
Vout=I × RPT100-I×Rw1+I×Rw3；
When three wire lengths and identical sectional area, existing Rw1=Rw2=Rw3, therefore
Vout=I × RPT100；
The above analysis is it is found that successfully counteract the error that sensor is brought due to lead.
It measures filter circuit and mainly filters out some High-frequency Interferences, because slow when temperature change.With operation amplifier
Device has built second order active low-pass filter circuit, 8 times of signal amplification factor.The cutoff frequency of second order active low-pass filter
Calculation formula is as follows：
Therefore by calculating, the cutoff frequency f of the utility modelp≈10Hz。
The output isolation circuit includes three phase metering chip, crystal oscillator Y1, resistance, the capacitance composition of model HT7017,
Three phase metering chip the 12nd, 13 pins be connected with crystal oscillator Y1, the both ends of crystal oscillator Y1 are followed by by capacitance C9 and capacitance C10 respectively
Ground, the 2nd pin of the 10th pin connection optocoupler U3 of three phase metering chip, the 11st pin connection optocoupler U2 of three phase metering chip
The 2nd pin, be in series with pull-up resistor R38 between the 1st pin and isolated power supply 5V of optocoupler U3, the 1st pin of optocoupler U2 with
Pull-up resistor R34 is in series between isolated power supply 5V.
Three phase metering chip is responsible for the output voltage signal of signal measurement filter circuit being converted to digital signal, and passes through
Subsequent conditioning circuit is defeated by USART oral instructions, to realize that the isolation of USART interfaces and subsequent conditioning circuit, the utility model have used photoelectricity coupling
Clutch is isolated, as shown in Fig. 2, the AD conversion first passage of HT7017 has been used, the output of INP1+ connection filter circuits,
The earth signal G5V of INP1- connection isolated power supplies；It is worth noting that, although the USAR mouths of HT7017 are real using photoelectrical coupler
Isolation is showed, but the power supply of this circuit should will also carry out isolation processing, specific there are two types of ways, first, being used alone one for it
Electric power loop, accordingly even when failure, which has occurred, will not influence other function modules, second is that being after existing plant-grid connection
It increases an isolated power supply module, realizes isolated from power.
The utility model passes through a large amount of experiment test, and precision, measurement range achieve the desired results, and in a new generation
It is used in motor protection product.
Although being described in conjunction with the accompanying the embodiment of the utility model, patent owner can want in appended right
Various deformations or amendments are made within the scope of asking, and model is protected as long as described no more than the claim of the utility model
It encloses, should all be within the protection scope of the utility model.
Claims (1)
1. a kind of motor temperature measuring circuit of band output isolation, it is characterised in that：It is exported including sequentially connected constant-current source
Circuit, signal measurement filter circuit and output isolation circuit；
The constant-current source output circuit includes voltage stabilizing chip LM431, operational amplifier U2A, operational amplifier U2B, positive pole
Cathode terminal through resistor R3 connection voltage stabilizing chips LM431, the control terminal of LM431 connect operation by resistance R5 with cathode terminal and put
The in-phase end of big device U2A, the output end of connection operational amplifier U2B, fortune after the in-phase end series resistance R4 of operational amplifier U2A
The output end and reverse side for calculating amplifier U2A are connected with resistance R1, and the reverse side series resistance R2 of operational amplifier U2A is followed by
The reverse side on ground, operational amplifier U2B is connected with output end, and the output end of operational amplifier U2A and operational amplifier U2B's is same
Phase end is connected with resistance Ref；
The signal measurement filter circuit includes operational amplifier U2C and operational amplifier U2D, sensor signal lines B1 series electricals
The reverse side of connection operational amplifier U2C, the reverse side and output end of operational amplifier U2C are connected with resistance R9 after resistance R8, transport
The in-phase end for calculating amplifier U2C connects sensor signal lines B2, the output end of operational amplifier U2C resistance R12 and resistance successively
The in-phase end of operational amplifier U2D is connected after R13, the in-phase end of operational amplifier U2D is also grounded by capacitance C10, and operation is put
It is grounded after the reverse side series resistance R6 of big device U2D, operation amplifier is connected after the reverse side series resistance R7 of operational amplifier U2D
The output end of device U2D；
The output isolation circuit includes three phase metering chip, crystal oscillator Y1, resistance, the capacitance composition of model HT7017, three-phase
Computation chip the 12nd, 13 pins be connected with crystal oscillator Y1, the both ends of crystal oscillator Y1 respectively by being grounded after capacitance C9 and capacitance C10,
The 2nd pin of the 10th pin connection optocoupler U3 of three phase metering chip, the 11st pin connection optocoupler U2's of three phase metering chip
2nd pin, is in series with pull-up resistor R38 between the 1st pin and isolated power supply 5V of optocoupler U3, the 1st pin of optocoupler U2 with every
From being in series with pull-up resistor R34 between power supply 5V.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721545102.7U CN207649787U (en) | 2017-11-18 | 2017-11-18 | A kind of motor temperature measuring circuit of band output isolation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201721545102.7U CN207649787U (en) | 2017-11-18 | 2017-11-18 | A kind of motor temperature measuring circuit of band output isolation |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN207649787U true CN207649787U (en) | 2018-07-24 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201721545102.7U Expired - Fee Related CN207649787U (en) | 2017-11-18 | 2017-11-18 | A kind of motor temperature measuring circuit of band output isolation |
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| CN (1) | CN207649787U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112930471A (en) * | 2018-08-31 | 2021-06-08 | 西门子股份公司 | Protective isolation module for an electric machine |
-
2017
- 2017-11-18 CN CN201721545102.7U patent/CN207649787U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112930471A (en) * | 2018-08-31 | 2021-06-08 | 西门子股份公司 | Protective isolation module for an electric machine |
| CN112930471B (en) * | 2018-08-31 | 2024-06-11 | 韦斯主轴技术有限公司 | Motor with protection isolation module |
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| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20180724 Termination date: 20211118 |