CN219830131U - Temperature sampling circuit - Google Patents
Temperature sampling circuit Download PDFInfo
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- CN219830131U CN219830131U CN202320146562.1U CN202320146562U CN219830131U CN 219830131 U CN219830131 U CN 219830131U CN 202320146562 U CN202320146562 U CN 202320146562U CN 219830131 U CN219830131 U CN 219830131U
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- 238000005070 sampling Methods 0.000 title claims abstract description 39
- 238000002955 isolation Methods 0.000 claims abstract description 39
- 230000003750 conditioning effect Effects 0.000 claims abstract description 32
- 239000003990 capacitor Substances 0.000 claims description 12
- 206010010071 Coma Diseases 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 101100489713 Saccharomyces cerevisiae (strain ATCC 204508 / S288c) GND1 gene Proteins 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
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Abstract
The utility model belongs to the technical field of power electronics, and particularly provides a temperature sampling circuit, which comprises: a three-phase temperature comparison branch, an isolation branch and a conditioning branch; the input end of the three-phase temperature comparison branch is connected with each corresponding measured power device and is used for collecting the respective temperature of each corresponding measured power device and selecting the highest temperature from the temperatures; the input end of the isolation branch is connected with the output end of the three-phase temperature comparison branch, is used for converting the highest temperature into a differential signal, and is used for realizing isolation between the three-phase temperature comparison branch and the conditioning branch; the input end of the conditioning branch is connected with the output end of the isolation branch and is used for converting the differential signals into analog signals for sampling by an external controller. Based on the technical scheme provided by the utility model, not only can the isolation sampling be realized, but also the cost is reduced.
Description
Technical Field
The utility model relates to the technical field of power electronics, in particular to a temperature sampling circuit.
Background
The operating temperature of the IGBT module of the power device of the frequency converter is a very important parameter, and the accuracy of temperature sampling is very important for the operation of the frequency converter.
For IGBT temperature sampling, the traditional circuits are generally two types, one type is a non-isolated sampling circuit, and the circuit has a simple structure, but has poor sampling efficiency and safety performance. In addition, the sampling is performed through a voltage-frequency and frequency-voltage conversion circuit, so that the circuit is often high in cost and is not beneficial to popularization and use.
Disclosure of Invention
In view of the problems in the prior art, the temperature sampling circuit provided by the utility model is an isolation circuit, so that the sampling efficiency and the safety performance are improved, the cost is reduced, and the popularization is facilitated.
In order to achieve the above object, a first aspect of the present utility model provides a temperature sampling circuit, comprising: a three-phase temperature comparison branch, an isolation branch and a conditioning branch; the input end of the three-phase temperature comparison branch is connected with each corresponding measured power device and is used for collecting the respective temperature of each corresponding measured power device and selecting the highest temperature from the temperatures; the input end of the isolation branch is connected with the output end of the three-phase temperature comparison branch, is used for converting the highest temperature into a differential signal, and is used for realizing isolation between the three-phase temperature comparison branch and the conditioning branch; the input end of the conditioning branch is connected with the output end of the isolation branch and is used for converting the differential signals into analog signals for sampling by an external controller.
The method comprises the steps of performing temperature sampling on a detected power device through three temperature comparison branches, selecting the highest temperature, outputting the highest temperature to an isolation branch, realizing signal differential processing and isolation functions through the isolation branch, and outputting the highest temperature to a conditioning branch for signal conversion, so that an analog signal which can be sampled by an external controller is obtained; the circuit provided by the aspect is simple in structure, so that the cost is reduced, and the circuit also has an isolation function, so that the sampling efficiency and the safety performance of the circuit are improved.
As an optional implementation manner of the first aspect, the three-phase temperature comparison branch includes: three temperature comparison sub-branches; wherein: the input end of the first temperature comparison subcircuit is connected with the first phase of the tested power device and is used for collecting a first temperature; the input end of the second temperature comparison subcircuit is connected with a second phase of the tested power device and is used for collecting a second temperature; and the input end of the third temperature comparison subcircuit is connected with a third phase of the tested power device and is used for collecting a third temperature.
As an optional implementation manner of the first aspect, the temperature comparison sub-branch includes: a first resistor, a voltage follower, and a diode; the positive input end of the voltage follower is connected with the tested power device and the first end of the first resistor; the negative input end of the voltage follower is connected with the positive electrode of the diode; the output end of the voltage follower is connected to the cathode of the diode; the positive power supply pin of the voltage follower is connected to the positive electrode of the first power supply; the negative power supply pin of the voltage follower is connected to the negative electrode of the first power supply; the second end of the first resistor is connected to a second power supply; the positive electrode of the diode is the output end of the three-phase temperature comparison branch circuit.
By the above, through setting up three temperature comparison sub-branches corresponding to the three phases of the frequency converter and respectively carrying out temperature sampling, then blocking lower temperature through the diode, only the branch corresponding to the highest temperature is output, thereby the highest temperature can be selected.
As an optional implementation manner of the first aspect, the isolation branch includes: the second resistor, the third resistor, the capacitor and the optocoupler device; the first end of the second resistor is connected with the output end of the three-phase temperature comparison branch, and the second end of the second resistor is connected with the first end of the third resistor; the first end of the third resistor is connected with the positive electrode of the third power supply, and the second end of the third resistor is connected with the ground end of the third power supply; the first end of the capacitor is connected with the positive electrode of the third power supply, and the second end of the capacitor is connected with the ground end of the third power supply; for the primary side of the optocoupler: the positive voltage input end is connected with the first end of the capacitor, the negative voltage input end and the ground end are connected with the ground end of the third power supply, and the power supply voltage end is connected with the positive electrode of the third power supply; for the secondary side of the optocoupler: the positive voltage output end and the negative voltage output end are output ends of the isolation branch and are used for connecting the conditioning branch; the ground terminal is connected with the ground terminal of the third power supply, and the power supply voltage terminal is connected with the positive electrode of the third power supply.
By the aid of the circuit, isolation and differential conversion of the circuit are achieved through the optocoupler, multiple functions are achieved through one device, and therefore the circuit structure is simplified, and circuit cost is saved.
As an optional implementation manner of the first aspect, the conditioning branch includes: the fourth resistor, the fifth resistor, the sixth resistor, the seventh resistor and the differential proportional operational amplifier; the first end of the fourth resistor and the first end of the sixth resistor are input ends of the conditioning branch and are used for being connected with output ends of the isolation branch; the positive input end of the differential proportional operational amplifier is connected with the second end of the fourth resistor, the negative input end of the differential proportional operational amplifier is connected with the second end of the sixth resistor, and the output end of the differential proportional operational amplifier is the output end of the conditioning branch and is used for outputting the analog signal; the positive power supply pin of the differential proportional operational amplifier is connected to the positive electrode of a fourth power supply, and the negative power supply pin of the differential proportional operational amplifier is connected to the negative electrode of the fourth power supply; the first end of the fifth resistor is connected with the second end of the fourth resistor, and the second end of the fifth resistor is connected with the ground; the first end of the seventh resistor is connected to the second end of the sixth resistor, and the second end of the seventh resistor is connected to the output end of the differential proportional operational amplifier.
From the above, the differential signal is processed by the differential proportional operational amplifier, thereby converting the differential signal into an analog signal for the controller to sample.
As an optional implementation manner of the first aspect, the method further includes: an eighth resistor; the first end of the eighth resistor is connected to the output end of the three-phase temperature comparison branch, and the second end of the eighth resistor is connected to a fifth power supply.
As an optional implementation manner of the first aspect, a supply voltage of the second power supply is 10V.
As an optional implementation manner of the first aspect, a supply voltage of the third power supply is 5V.
As an optional implementation manner of the first aspect, a supply voltage of the fourth power supply is 5V.
As an optional implementation manner of the first aspect, a supply voltage of the fifth power supply is 15V.
These and other aspects of the utility model will be apparent from and elucidated with reference to the embodiment(s) described hereinafter.
Drawings
The respective technical features of the present utility model and their relationships are further described below with reference to the drawings. The drawings are exemplary, some technical features are not shown in actual proportion, and some technical features that are conventional in the technical field to which the present utility model pertains and that are not essential to understanding and realizing the present utility model may be omitted from some drawings, or technical features that are not essential to understanding and realizing the present utility model are additionally shown, that is, the combination of the various technical features shown in the drawings is not intended to limit the present utility model. In addition, throughout the present utility model, the same reference numerals are used to designate the same. The specific drawings are as follows:
fig. 1 is a schematic circuit diagram of a temperature sampling circuit according to an embodiment of the present utility model.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the present utility model more apparent, the embodiments of the present utility model will be described in further detail with reference to the accompanying drawings.
It should be understood that, since the principles of solving the problems in the embodiments of the present utility model are the same or similar, in the following description of the specific embodiments, some repetition may not be described, but it should be considered that the specific embodiments have mutual references and may be combined with each other.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this utility model belongs. If there is a discrepancy, the meaning described in the present specification or the meaning obtained from the content described in the present specification is used. In addition, the terminology used herein is for the purpose of describing embodiments of the utility model only and is not intended to be limiting of the utility model.
A detailed description will be given of a temperature sampling circuit provided in an embodiment of the present utility model with reference to the drawings.
As shown in fig. 1, a circuit structure diagram of a temperature sampling circuit according to an embodiment of the present utility model is shown. In this embodiment, the temperature sampling circuit 10 includes a three-phase temperature comparison branch 110, an isolation branch 120, and a conditioning branch 130. Wherein, the input end of the three-phase temperature comparison branch 110 is connected with each corresponding tested power device; the input end of the isolation branch 120 is connected to the output end of the three-phase temperature comparison branch 110; the input end of the conditioning branch 130 is connected to the output end of the isolation branch 120, and the output end of the conditioning branch 130 is the output end of the temperature sampling circuit 10 and is used for being connected to an external controller. In this embodiment, the power device to be measured may be an IGBT in a frequency converter. The individual branches are described in detail in sequence below.
The three-phase temperature comparison branch 110 is used for collecting the respective temperatures of the corresponding tested power devices, and selecting the highest temperature from the temperatures. Specifically, the three-phase temperature comparing sub-circuit 110 includes three temperature comparing sub-circuits with the same structure, namely, a first temperature comparing sub-circuit, a second temperature comparing sub-circuit, and a third temperature comparing sub-circuit in fig. 1. The input end of the first temperature comparison subcircuit is used for being connected with a first phase of a tested power device to acquire a first temperature TEMP1; the input end of the second temperature comparison subcircuit is used for connecting a second phase of the tested power device to acquire a second temperature TEMP2; the third temperature comparison subcircuit is used for being connected with a third phase of the tested power device to acquire a third temperature TEMP3.
The connection relationship of the components will be described in detail below by taking the first temperature comparison subcircuit as an example. As shown in fig. 1, the first temperature comparison subcircuit includes a first resistor R1, a voltage follower U12, and a diode D1.
The positive input end of the voltage follower U12 is connected to the tested power device and the first end of the first resistor R1 and is used for collecting a first temperature TEMP1; the negative input end of the voltage follower U12 is connected with the positive electrode of the diode D1; the output end of the voltage follower U12 is connected to the cathode of the diode D1; the positive power supply pin of the voltage follower U12 is connected with the positive pole VA+ of the first power supply; the negative supply pin of the voltage follower U12 is connected to the negative terminal COMA of the first supply source.
The second end of the first resistor R1 is connected to a second power supply, and the power supply of the second power supply is typically 10V.
The anode of the diode D1 is an output end of the three-phase temperature comparison branch 110, and is used for connecting with the isolation circuit 120.
It should be understood that the circuit structures of the second temperature comparing sub-branch and the third temperature comparing sub-branch are the same as those of the first temperature comparing sub-branch, so that the description thereof will not be repeated. In addition, since the voltage followers of the three sub-branches are the same chip, the positive power supply pin and the negative power supply pin of the voltage follower U12 are only required to be connected to the corresponding power supply in one sub-branch, and the positive power supply pin and the negative power supply pin in the other two sub-branches are in a floating state, for example, the positive power supply pin and the negative power supply pin of the first temperature comparison sub-branch are in a connection state in fig. 1, and the positive power supply pin and the negative power supply pin of the second temperature comparison sub-branch and the third temperature comparison sub-branch are in a floating state.
The isolation branch 120 is used to transform the highest temperature into a differential signal and to achieve isolation between the three-phase temperature comparison branch 110 and the conditioning branch 130. Specifically, the isolation branch 120 includes a second resistor R2, a third resistor R3, a capacitor C, and an optocoupler U13.
The first end of the second resistor R2 is used as the input end of the isolation branch 120 and is connected with the output end of the three-phase temperature comparison branch 110, i.e. the second resistor R2 is connected with the anode of the diode D1 in the three-phase temperature comparison branch 110; the second end of the second resistor R2 is connected with the first end of the third resistor R3;
the first end of the third resistor R3 is also connected to the positive electrode A5V of the third power supply, and the second end of the third resistor R3 is connected to the ground end COMA of the third power supply.
The first end of the capacitor C is connected with the positive electrode A5V of the third power supply, and the second end of the capacitor C is connected with the ground end COMA of the third power supply.
For the optocoupler U13, the connection relationship thereof is divided into a connection relationship of a primary side and a connection relationship of a secondary side. For the primary side: the positive voltage input terminal vin+ is connected to the first terminal of the capacitor C, and the negative voltage input terminal VIN-and the ground terminal GND1 are connected to the ground terminal COMA of the third power supply. For the secondary side: the positive voltage output terminal vout+ and the negative voltage output terminal VOUT-are used as output terminals of the isolation branch 120 and are used for connecting the conditioning branch 130; the ground terminal is connected with the ground terminal of the third power supply, and the power supply voltage terminal is connected with the positive electrode of the third power supply. In this embodiment, the power supply voltage of the third power supply is generally 5V.
The conditioning branch 130 is used to convert the differential signal to an analog signal for sampling by an external controller. In this embodiment, the conditioning branch 130 is a primary conditioning branch. Specifically, the conditioning branch 130 includes a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, and a differential proportional operational amplifier U14. The input end of the conditioning branch 130 is a first end of the fourth resistor R4 and a first end of the sixth resistor R6, and is used for connecting with the output end of the isolation branch 120. Specifically, a first end of the fourth resistor R4 is connected to a positive voltage output terminal vout+ of the secondary side of the optocoupler U13, and a first end of the sixth resistor R6 is connected to a negative voltage output terminal VOUT-of the secondary side of the optocoupler U13.
The positive input end of the differential proportional operational amplifier U14 is connected with the second end of the fourth resistor R4; the negative input end of the differential proportional operational amplifier U14 is connected with the second end of the sixth resistor R6; the output end of the differential proportional operational amplifier U14 is connected with the second end of the seventh resistor R7 and used as the output end of the conditioning branch 130 for outputting an analog signal to an external controller; the positive power supply pin of the differential proportional operational amplifier U14 is connected to the positive pole of the fourth power supply, and the negative power supply pin of the differential proportional operational amplifier U14 is connected to the negative pole of the fourth power supply. The power supply voltage of the fourth power supply is typically 5V.
The first end of the fifth resistor R5 is connected to the second end of the fourth resistor R4, and the second end of the fifth resistor R5 is connected to the ground G.
The first end of the seventh resistor R7 is connected to the second end of the sixth resistor R6, and the second end of the seventh resistor R7 is connected to the output end of the differential proportional operational amplifier U14, and is used as the output end of the conditioning branch 130.
As shown in fig. 1, the temperature sampling circuit further includes an eighth resistor R8, wherein a first end of the eighth resistor R8 is connected to the output end of the three-phase temperature comparing branch 110, that is, a first end of the eighth resistor R8 is connected to the anode of the diode D1; the second end of the eighth resistor R8 is connected to the fifth power supply. In this embodiment, the voltage of the fifth power supply is typically 15V.
The following describes the operation principle of the temperature sampling circuit 10 based on the above embodiment.
As shown in fig. 1, temperatures of a thermistor (NTC) in an IGBT of a power device under test in a frequency converter are respectively collected through three-phase input ends of a three-phase temperature comparison branch 110 to obtain TEMP1, TEMP2 and TEMP3, and then a branch where a maximum value of the three-phase temperatures TEMP1, TEMP2 and TEMP3 is located is conducted through cooperation of a voltage follower U12 and a diode D1, and the other two branches are cut off, so that a maximum temperature value is output to an isolation branch 120. The optocoupler U13 in the isolation branch 120 performs differential conversion on the maximum temperature value, and performs isolation between the primary side circuit (three-phase temperature comparison branch 110) and the secondary side circuit (conditioning branch) while obtaining a differential signal of the maximum temperature value. The differential signal is then transformed by the conditioning branch 130 to obtain a suitable analog signal for output to the controller.
The temperature sampling circuit provided by the embodiment of the utility model has the advantages of simple circuit structure and lower cost. Not only can accurate temperature sampling be realized, but also a good isolation effect is achieved, so that the circuit safety is ensured.
Reference in the specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the utility model. Thus, appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment, but may. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments as would be apparent to one of ordinary skill in the art from this disclosure.
Note that the above is only a preferred embodiment of the present utility model and the technical principle applied. It will be understood by those skilled in the art that the present utility model is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the utility model. Therefore, while the utility model has been described in connection with the above embodiments, the utility model is not limited to the above embodiments, but may include many other equivalent embodiments without departing from the spirit of the utility model, which fall within the scope of the utility model.
Claims (10)
1. A temperature sampling circuit, comprising: a three-phase temperature comparison branch, an isolation branch and a conditioning branch;
the input end of the three-phase temperature comparison branch is connected with each corresponding measured power device and is used for collecting the respective temperature of each corresponding measured power device and selecting the highest temperature from the temperatures;
the input end of the isolation branch is connected with the output end of the three-phase temperature comparison branch, is used for converting the highest temperature into a differential signal, and is used for realizing isolation between the three-phase temperature comparison branch and the conditioning branch;
the input end of the conditioning branch is connected with the output end of the isolation branch and is used for converting the differential signals into analog signals for sampling by an external controller.
2. The temperature sampling circuit of claim 1, wherein the three-phase temperature comparison branch comprises: three temperature comparison sub-branches; wherein:
the input end of the first temperature comparison subcircuit is connected with the first phase of the tested power device and is used for collecting a first temperature;
the input end of the second temperature comparison subcircuit is connected with a second phase of the tested power device and is used for collecting a second temperature;
and the input end of the third temperature comparison subcircuit is connected with a third phase of the tested power device and is used for collecting a third temperature.
3. The temperature sampling circuit of claim 2, wherein the temperature comparison subcircuit comprises: a first resistor, a voltage follower, and a diode;
the positive input end of the voltage follower is connected with the tested power device and the first end of the first resistor; the negative input end of the voltage follower is connected with the positive electrode of the diode; the output end of the voltage follower is connected to the cathode of the diode; the positive power supply pin of the voltage follower is connected to the positive electrode of the first power supply; the negative power supply pin of the voltage follower is connected to the negative electrode of the first power supply;
the second end of the first resistor is connected to a second power supply;
the positive electrode of the diode is the output end of the three-phase temperature comparison branch circuit.
4. The temperature sampling circuit of claim 1, wherein the isolation leg comprises: the second resistor, the third resistor, the capacitor and the optocoupler device;
the first end of the second resistor is connected with the output end of the three-phase temperature comparison branch, and the second end of the second resistor is connected with the first end of the third resistor;
the first end of the third resistor is connected with the positive electrode of the third power supply, and the second end of the third resistor is connected with the ground end of the third power supply;
the first end of the capacitor is connected with the positive electrode of the third power supply, and the second end of the capacitor is connected with the ground end of the third power supply;
for the primary side of the optocoupler: the positive voltage input end is connected with the first end of the capacitor, the negative voltage input end and the ground end are connected with the ground end of the third power supply, and the power supply voltage end is connected with the positive electrode of the third power supply;
for the secondary side of the optocoupler: the positive voltage output end and the negative voltage output end are output ends of the isolation branch and are used for connecting the conditioning branch; the ground terminal is connected with the ground terminal of the third power supply, and the power supply voltage terminal is connected with the positive electrode of the third power supply.
5. The temperature sampling circuit of claim 1, wherein the conditioning branch comprises: the fourth resistor, the fifth resistor, the sixth resistor, the seventh resistor and the differential proportional operational amplifier; the first end of the fourth resistor and the first end of the sixth resistor are input ends of the conditioning branch and are used for being connected with output ends of the isolation branch;
the positive input end of the differential proportional operational amplifier is connected with the second end of the fourth resistor, the negative input end of the differential proportional operational amplifier is connected with the second end of the sixth resistor, and the output end of the differential proportional operational amplifier is the output end of the conditioning branch and is used for outputting the analog signal; the positive power supply pin of the differential proportional operational amplifier is connected to the positive electrode of a fourth power supply, and the negative power supply pin of the differential proportional operational amplifier is connected to the negative electrode of the fourth power supply;
the first end of the fifth resistor is connected with the second end of the fourth resistor, and the second end of the fifth resistor is connected with the ground;
the first end of the seventh resistor is connected to the second end of the sixth resistor, and the second end of the seventh resistor is connected to the output end of the differential proportional operational amplifier.
6. The temperature sampling circuit of claim 1, further comprising: an eighth resistor;
the first end of the eighth resistor is connected to the output end of the three-phase temperature comparison branch, and the second end of the eighth resistor is connected to a fifth power supply.
7. A temperature sampling circuit according to claim 3, wherein the supply voltage of the second supply source is 10V.
8. The temperature sampling circuit of claim 4, wherein the third power supply has a supply voltage of 5V.
9. The temperature sampling circuit of claim 5, wherein the fourth power supply has a supply voltage of 5V.
10. The temperature sampling circuit of claim 6, wherein the supply voltage of the fifth supply is 15V.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202320146562.1U CN219830131U (en) | 2023-01-16 | 2023-01-16 | Temperature sampling circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202320146562.1U CN219830131U (en) | 2023-01-16 | 2023-01-16 | Temperature sampling circuit |
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| Publication Number | Publication Date |
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| CN219830131U true CN219830131U (en) | 2023-10-13 |
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| CN202320146562.1U Active CN219830131U (en) | 2023-01-16 | 2023-01-16 | Temperature sampling circuit |
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| CN (1) | CN219830131U (en) |
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