CN113701911B - Electric energy meter terminal temperature detection circuit and method - Google Patents
Electric energy meter terminal temperature detection circuit and method Download PDFInfo
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- CN113701911B CN113701911B CN202010424855.2A CN202010424855A CN113701911B CN 113701911 B CN113701911 B CN 113701911B CN 202010424855 A CN202010424855 A CN 202010424855A CN 113701911 B CN113701911 B CN 113701911B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
- G01K7/16—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements
- G01K7/22—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using resistive elements the element being a non-linear resistance, e.g. thermistor
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
- G01K1/00—Details of thermometers not specially adapted for particular types of thermometer
- G01K1/02—Means for indicating or recording specially adapted for thermometers
- G01K1/028—Means for indicating or recording specially adapted for thermometers arrangements for numerical indication
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Abstract
The invention provides a circuit and a method for detecting the temperature of a terminal of an electric energy meter, comprising the following steps: the terminal temperature detection module detects an ammeter terminal and outputs a temperature voltage signal; the temperature voltage signal processing module amplifies the temperature voltage signal, converts the temperature voltage signal into a digital signal and then carries out digital processing; when the temperature voltage signal is smaller than a set value, an adjustable gain amplifier is adopted to amplify the signal, and when the temperature voltage signal is larger than the set value, a unit gain amplifier is adopted to amplify the signal; and performing analog-to-digital conversion and digital processing on the amplified temperature voltage signal. The invention utilizes two different amplifiers to process the temperature signal: one amplifier amplifies signals at low temperature and the other amplifies signals at other temperatures to improve detection accuracy and precision; the low-temperature small-signal amplifier adopts a high input impedance and fully differential architecture, improves the common-mode voltage range of signals, and is suitable for application environments in which the resistance of a signal source changes in a large range.
Description
Technical Field
The invention relates to the field of electric energy metering, in particular to a circuit and a method for detecting the temperature of a terminal of an electric energy meter.
Background
The electric energy represents a metering tool for counting the electricity consumption of a power unit, and has the characteristics of stable and reliable performance, long service life, small volume, convenient programming, multiple purposes in one meter and the like. Along with the rapid development of the economy in China, the electric energy requirements of various industries are larger and larger, and the management and control of the electric energy through the metering data of the electric energy meter are more and more important.
In the application of the electric energy meter, the electric meter terminal is connected with high voltage and high current, and if the electric meter terminal fails, the electric meter is easily burnt at high temperature, so that the electric meter is damaged. The safe use of the electric energy meter is not only related to the normal operation of the power grid system but also related to the life and property safety of people, so that the electric energy meter can be reasonably regulated and protected by detecting the terminal temperature of the electric energy meter, thereby preventing the electric energy meter from being damaged and protecting the electric energy meter system.
How to improve the accuracy of electronic temperature detection of an ammeter and improve the safety of ammeter application has become one of the problems to be solved urgently by those skilled in the art.
Disclosure of Invention
In view of the above-mentioned drawbacks of the prior art, an objective of the present invention is to provide a circuit and a method for detecting a temperature of a terminal of an electric energy meter, which are used for solving the safety problem caused by the failure of the terminal of the electric energy meter in the prior art.
To achieve the above and other related objects, the present invention provides an electric energy meter terminal temperature detection circuit, which at least includes:
the terminal temperature detection module is used for detecting the temperature of the ammeter terminal and outputting a corresponding temperature voltage signal;
and the temperature voltage signal processing module is connected to the output end of the terminal temperature detection module, amplifies the temperature voltage signal based on the value of the temperature voltage signal, converts the temperature voltage signal into a digital signal and then carries out digital processing.
Optionally, the terminal temperature detection module comprises a temperature sensitive resistor and a first resistor; the first end of the temperature-sensitive resistor is connected with a power supply voltage, the second end of the temperature-sensitive resistor is connected with the first end of the first resistor, and the second end of the first resistor is grounded; the first end of the first resistor outputs the temperature voltage signal.
More optionally, the terminal temperature detection module further comprises a second resistor; the second resistor is connected between the temperature sensitive resistor and the first resistor.
More optionally, the terminal temperature detection module further includes a filter capacitor; one end of the filter capacitor is connected with the first end of the first resistor, and the other end of the filter capacitor is grounded.
Optionally, the temperature voltage signal processing module comprises an adjustable gain amplifier, a unit gain amplifier, a selector, an analog-to-digital converter and a digital processor;
the adjustable gain amplifier receives the temperature voltage signal and amplifies the temperature voltage signal;
the unit gain amplifier receives the temperature voltage signal and amplifies the temperature voltage signal;
the selector is connected with the output ends of the adjustable gain amplifier and the unit gain amplifier, and is used for selecting the output signal of the adjustable gain amplifier to output when the temperature voltage signal is smaller than a set value and selecting the output signal of the unit gain amplifier to output when the temperature voltage signal is larger than the set value;
the analog-to-digital converter is connected to the output end of the selector and is used for performing analog-to-digital conversion on the output signal of the selector;
the digital processor is connected with the output end of the analog-to-digital converter and the control end of the selector, processes the digital signal output by the analog-to-digital converter, and detects the amplitude of the digital signal to generate a selection control signal of the selector.
More optionally, the adjustable gain amplifier employs a fully differential input-output, and a high impedance input amplifier.
More optionally, the adjustable gain amplifier includes a first operational amplifier, a first resistor, a second resistor, a fifth resistor, and a sixth resistor; the first inverting input end of the first operational amplifier is connected with the output end of the terminal temperature detection module, and the first non-inverting input end of the first operational amplifier is grounded; the non-inverting output end of the first operational amplifier is connected with the second inverting input end of the first operational amplifier through the first resistor; the inverting output end of the first operational amplifier is connected with the second non-inverting input end of the first operational amplifier through the second resistor; the fifth resistor and the sixth resistor are connected in series and then connected between the second inverting input end and the second non-inverting input end of the first operational amplifier.
More optionally, the unit gain amplifier includes a second operational amplifier, a non-inverting input terminal of the second operational amplifier is connected to an output terminal of the terminal temperature detection module, and an inverting input terminal of the second operational amplifier is connected to an output terminal of the second operational amplifier.
More optionally, the analog-to-digital converter is a Sigma-Delta analog-to-digital converter.
To achieve the above and other related objects, the present invention provides a method for detecting a terminal temperature of an electric energy meter, the method at least comprising:
detecting the temperature of a terminal of the electric energy meter, and obtaining a temperature voltage signal;
when the temperature voltage signal is smaller than a set value, an adjustable gain amplifier is adopted to amplify the temperature voltage signal, and when the temperature voltage signal is larger than the set value, a unit gain amplifier is adopted to amplify the temperature voltage signal, so that the detection precision is improved;
and carrying out analog-to-digital conversion on the amplified temperature voltage signal to obtain a digital signal, and carrying out digital processing on the digital signal to obtain a temperature detection signal.
Optionally, a fully differential input/output and high-impedance adjustable gain amplifier structure is adopted, so that the detection precision is improved and the common-mode voltage value is improved.
Optionally, the magnitude of the digital signal is detected when digital processing is performed, so as to judge the relation between the temperature voltage signal and the set value.
More optionally, the adjustable gain amplifier has a magnification factor of 2, 4, 8 or 16.
As described above, the electric energy meter terminal temperature detection circuit and method of the invention have the following beneficial effects:
1. the electric energy meter terminal temperature detection circuit and the method of the invention utilize two different amplifiers to process temperature signals: one amplifier amplifies the signal (low voltage) at low temperature and the other amplifier amplifies the signal at other temperature, thereby improving detection accuracy and precision.
2. The low-temperature small-signal amplifier in the electric energy meter terminal temperature detection circuit and the method adopts a high input impedance and fully differential architecture, so that the common-mode voltage range of signals is improved, and the circuit and the method are simultaneously applicable to application environments in which the resistance of a signal source is widely changed.
Drawings
Fig. 1 is a schematic diagram of a circuit for detecting a terminal temperature of an electric energy meter according to the present invention.
Fig. 2 is a schematic diagram of an adjustable gain amplifier according to the present invention.
Fig. 3 is a schematic diagram showing the structure of the unity gain amplifier of the present invention.
Description of element reference numerals
1. Electric energy meter terminal temperature detection circuit
11. Terminal temperature detection module
12. Temperature voltage signal processing module
121. Gain-adjustable amplifier
122. Unity gain amplifier
123. Selector
124. Analog-to-digital converter
125. Digital processor
Detailed Description
Other advantages and effects of the present invention will become apparent to those skilled in the art from the following disclosure, which describes the embodiments of the present invention with reference to specific examples. The invention may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present invention.
Please refer to fig. 1-3. It should be noted that, the illustrations provided in the present embodiment merely illustrate the basic concept of the present invention by way of illustration, and only the components related to the present invention are shown in the drawings and are not drawn according to the number, shape and size of the components in actual implementation, and the form, number and proportion of the components in actual implementation may be arbitrarily changed, and the layout of the components may be more complex.
Example 1
As shown in fig. 1, the present embodiment provides an electric energy meter terminal temperature detection circuit 1, the electric energy meter terminal temperature detection circuit 1 including:
the terminal temperature detection module 11 and the temperature voltage signal processing module 12.
As shown in fig. 1, the terminal temperature detection module 11 is configured to detect a terminal temperature of an electric meter and output a corresponding temperature voltage signal Vthermal.
Specifically, in this embodiment, the terminal temperature detection module 11 includes a temperature-sensitive resistor Rthermal and a first resistor R1, where the temperature-sensitive resistor Rthermal is connected in series with the first resistor R1. The first end of the temperature-sensitive resistor Rthermal is connected with a power supply voltage VCC, and the second end of the temperature-sensitive resistor Rthermal is connected with the first end of the first resistor R1. The first end of the first resistor R1 is connected with the second end of the temperature-sensitive resistor Rthermal and outputs the temperature voltage signal Vthermal, and the second end is grounded. In order to make the temperature detection range large enough and make the detection precision high, the temperature-sensitive resistor Rthermal can select a temperature-sensitive resistor with a resistance value which changes greatly enough along with the temperature change (can be selected based on actual needs and is not described in detail here). The first resistor R1 and the temperature-sensitive resistor Rthermal are connected in series to divide the voltage of the power supply voltage VCC and sample the voltage to obtain a temperature voltage signal Vthermal which changes along with the temperature.
Specifically, as another implementation manner of the present embodiment, the terminal temperature detection module 11 further includes a second resistor R2. The second resistor R2 is connected between the temperature-sensitive resistor Rthermal and the first resistor R1, and a connection node between the first resistor R1 and the second resistor R2 outputs the temperature voltage signal Vthermal. The second resistor R2 is used for acting together with the first resistor R1, and further adjusts the voltage of the temperature voltage signal Vthermal according to the input requirement of the detection circuit. It should be noted that, the second resistor R2 may be selected according to the voltage dividing requirement, and is not limited to this embodiment.
Specifically, as another implementation manner of the present embodiment, the terminal temperature detection module 11 further includes a filter capacitor C0. One end of the filter capacitor C0 is connected with the first end of the first resistor R1, and the other end of the filter capacitor C0 is grounded. The filter capacitor C0 is configured to filter the temperature voltage signal Vthermal after resistor voltage division, so as to remove clutter after voltage division. It should be noted that, the filter capacitor C0 may be selected according to actual needs, and is not limited to this embodiment.
In this embodiment, the temperature voltage signal Vthermal voltage satisfies the following relationship:
Vthermal＝VCC*(R1/(Rthermal+R1+R2))
it is assumed here that the temperature is chosen from-40 deg.c to 200 deg.c and that the temperature sensitive resistance Rthermal varies from about 3mΩ to 0.5kΩ. Here, the resistance value of the first resistor R1 may be selected to be at the middle temperature (i.e., 80 ℃) of the temperature-sensitive resistor Rthermal detection range, so that the temperature voltage signal Vthermal voltage may be uniform at a level Wen Fenya, and the resistance value of the first resistor R1 may be selected to be about 12kΩ.
Assuming that the resistance of the second resistor R2 is 0, vcc=3.3v, it can be seen from the voltage division relationship that at low temperature, the temperature voltage signal vthermal=12 mV; at high temperature, the temperature voltage signal vthermal=3.168V. The resistance of the second resistor R2 may be increased to decrease the voltage value of the temperature voltage signal Vthermal.
It should be noted that any circuit capable of realizing temperature detection is suitable for the terminal temperature detection module of the present invention, and the circuit structure is not limited to the present embodiment, and the circuit structure is composed of devices such as a bipolar transistor, a PN junction diode, a metal oxide semiconductor field effect transistor, and the like.
As shown in fig. 1, the temperature-voltage signal processing module 12 is connected to the output end of the terminal temperature detection module 11, amplifies the temperature-voltage signal Vthermal based on the value of the temperature-voltage signal Vthermal, and converts the temperature-voltage signal Vthermal into a digital signal for digital processing.
Specifically, in the present embodiment, the temperature-voltage signal processing module 12 includes an adjustable gain amplifier 121, a unity gain amplifier 122, a selector 123, an analog-to-digital converter 124, and a digital processor 125.
More specifically, when the temperature voltage signal Vthermal is low in voltage, for a normal amplifier, the input voltage is small, and the amplifier input and output easily enter a linear region, resulting in amplification deviation, so the present invention adopts the adjustable gain amplifier 121 for signal amplification to realize high-precision temperature detection. The gain-adjustable amplifier 121 receives the temperature voltage signal Vthermal, and amplifies the temperature voltage signal Vthermal at low temperature. In this embodiment, the adjustable gain amplifier 121 (PGA) uses a fully differential input/output and inputs a high impedance amplifier. The adjustable gain amplifier 121 includes a first operational amplifier OP1, a third resistor R3, a fourth resistor R4, a fifth resistor R5, and a sixth resistor R6, wherein a first inverting input terminal of the first operational amplifier OP1 is connected to an output terminal (vin+), and a first non-inverting input terminal is grounded (Vin-); the non-inverting output terminal (vout+) of the first operational amplifier OP1 is connected to the second inverting input terminal of the first operational amplifier OP1 via the third resistor R3; the inverting output end of the first operational amplifier OP1 is connected with the second non-inverting input end of the first operational amplifier OP1 through the fourth resistor R4; the fifth resistor R5 and the sixth resistor R6 are connected in series and then connected between the second inverting input terminal and the second non-inverting input terminal of the first operational amplifier OP 1. The adjustable gain amplifier 121 uses a resistor ratio to achieve different multiple amplification, and optional amplification includes, but is not limited to, 2, 4, 8, and 16 multiple amplification, where the gain formula is: gain= (ra+rb)/Ra, where Ra is the resistance of the fifth resistor R5 and the sixth resistor R6, and Rb is the resistance of the third resistor R3 and the fourth resistor R4. The gain-adjustable amplifier 121 adopts a fully differential architecture amplifier OP1, and after the fully differential architecture amplifies the input signal, the input signal biased at 0V can be raised to an intermediate voltage of VCC/2 by raising the common-mode voltage value of the signal. The adjustable gain amplifier 121 thus effectively amplifies the signal even when a small voltage or even a negative voltage is input.
In the present embodiment, a low temperature is determined when the temperature is lower than the set value; the specific temperature determination as to whether the temperature is low can be set according to actual needs, and will not be described in detail herein.
More specifically, at other temperatures, the unity gain amplifier 122 is employed to amplify the signal. The unity gain amplifier 122 receives the temperature voltage signal Vthermal and amplifies the temperature voltage signal Vthermal at other temperatures. In this embodiment, the unity gain amplifier 122 (PGA) adopts a rail-to-rail (rail-to-rail) structure amplifier with an amplification factor of 1. The unity gain amplifier 122 includes a second operational amplifier OP2, wherein a non-inverting input terminal of the second operational amplifier OP2 is connected to the output terminal (vin+) of the terminal temperature detection module 11, and an inverting input terminal is connected to the output terminal (Vout) of the second operational amplifier OP 2. In practical use, the amplification factor can be set according to practical needs, and different amplifier structures can be selected according to needs, not limited by the embodiment.
More specifically, the selector 123 is connected to the output ends of the adjustable gain amplifier 121 and the unity gain amplifier 122, and selects the output signal of the adjustable gain amplifier 121 when the temperature voltage signal Vthermal is smaller than a set value, and selects the output signal of the unity gain amplifier 122 when the temperature voltage signal Vthermal is larger than the set value. In this embodiment, the selector 123 is a two-out selector, and the selection signal Sel is provided by the digital processor 125. Any circuit structure capable of realizing alternative is suitable for the present invention, and is not described in detail herein.
More specifically, the analog-to-digital converter 124 is connected to the output terminal of the selector 123, and performs analog-to-digital conversion on the output signal of the selector 123. In this embodiment, the analog-to-digital converter 124 is a Sigma-Delta (Σ - Δ) analog-to-digital converter, which has the same architecture as the analog-to-digital converter in the electric energy metering circuit in the electric energy meter, and shares the same reference voltage VREF (the reference voltage VREF is a high-precision reference voltage). In practical use, the architecture of the analog-to-digital converter 124 can be set based on practical needs, which is not limited to the present embodiment.
More specifically, the digital processor 125 is connected to the output end of the analog-to-digital converter 124 and the control end of the selector 123, and processes the digital signal output by the analog-to-digital converter 124; and detecting the amplitude of the digital signal, predicting the temperature point at the moment, generating a selection control signal of the selector 123 according to the judged temperature point, and then selecting whether to use the adjustable gain amplifier 121 or the unit gain amplifier 122 to amplify the signal through the selector 123. In this embodiment, the digital processor 125 has the same architecture as the digital processing unit of the power metering circuit. In practical use, the architecture of the digital processor 125 can be set based on practical needs, which is not limited to the present embodiment.
The electric energy meter terminal temperature detection circuit of the invention utilizes two different amplifiers to process temperature signals: one amplifier amplifies the signal (low voltage) at low temperature, and the other amplifier amplifies the signal at other temperature, so that the detection precision and accuracy are improved; meanwhile, the low-temperature small-signal amplifier adopts a high input impedance and fully differential architecture, so that the common-mode voltage range of the signal is improved, and the low-temperature small-signal amplifier is suitable for application environments in which the resistance of the signal source is widely changed.
Example two
The embodiment provides a method for detecting the temperature of a terminal of an electric energy meter, which comprises the following steps:
detecting the temperature of a terminal of the electric energy meter, and obtaining a temperature voltage signal Vthermal;
when the temperature voltage signal Vthermal is smaller than a set value, an adjustable gain amplifier is adopted to amplify the temperature voltage signal Vthermal, and when the temperature voltage signal Vthermal is larger than the set value, a unit gain amplifier is adopted to amplify the temperature voltage signal Vthermal, so that the detection precision is improved;
and carrying out analog-to-digital conversion on the amplified temperature voltage signal Vthermal to obtain a digital signal, and carrying out digital processing on the digital signal to obtain a temperature detection signal.
Specifically, in this embodiment, the electric energy meter terminal temperature detection circuit 1 of the first embodiment is used to implement the electric energy meter terminal temperature detection method of the present invention, and in practical use, any hardware circuit or software algorithm capable of implementing the electric energy meter terminal temperature detection method of the present invention is suitable.
Specifically, the invention adopts two groups of high-precision amplifiers, and different amplifiers are selected to amplify the temperature measurement voltage according to the temperature induction voltage measured at different temperature points. The signal amplification is performed by adopting an adjustable gain amplifier at low temperature, the adjustable gain amplifier adopts a fully differential input and output structure, and the input high impedance structure is adopted, the amplification factor can be set to be 2, 4, 8 or 16 times based on the requirement, so that the common-mode voltage range of the signal is improved, and the signal source resistor is simultaneously suitable for application environments with wide range of variation of the signal source resistor. At other temperatures (other than low temperatures), signal amplification is performed using a unity gain amplifier, with amplification factors including, but not limited to, 1.
Specifically, the amplitude of the digital signal is detected during digital processing to judge the relation between the temperature voltage signal and the set value, so as to determine when to amplify the signal by using an adjustable gain amplifier.
The method for detecting the temperature of the electric energy meter terminal can further improve the detection precision and ensure the safe use of the electric energy meter.
In summary, the present invention provides a circuit and a method for detecting a terminal temperature of an electric energy meter, including: the terminal temperature detection module is used for detecting the temperature of the ammeter terminal and outputting a corresponding temperature voltage signal; and the temperature voltage signal processing module is connected to the output end of the terminal temperature detection module, amplifies the temperature voltage signal based on the value of the temperature voltage signal, converts the temperature voltage signal into a digital signal and then carries out digital processing. Detecting the temperature of a terminal of the electric energy meter, and obtaining a temperature voltage signal; when the temperature voltage signal is smaller than a set value, an adjustable gain amplifier is adopted to amplify the temperature voltage signal, and when the temperature voltage signal is larger than the set value, a unit gain amplifier is adopted to amplify the temperature voltage signal, so that the detection precision is improved; and carrying out analog-to-digital conversion on the amplified temperature voltage signal to obtain a digital signal, and carrying out digital processing on the digital signal to obtain a temperature detection signal. The electric energy meter terminal temperature detection circuit and the method of the invention utilize two different amplifiers to process temperature signals: one amplifier amplifies the signal (low voltage) at low temperature, and the other amplifier amplifies the signal at other temperature, so that the detection precision and accuracy are improved; the low-temperature small-signal amplifier adopts a high input impedance and fully differential architecture, so that the common-mode voltage range of signals is improved, and the low-temperature small-signal amplifier is simultaneously suitable for application environments in which the resistance of a signal source is widely changed. Therefore, the invention effectively overcomes various defects in the prior art and has high industrial utilization value.
The above embodiments are merely illustrative of the principles of the present invention and its effectiveness, and are not intended to limit the invention. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is intended that all equivalent modifications and variations of the invention be covered by the claims, which are within the ordinary skill of the art, be within the spirit and scope of the present disclosure.
Claims (12)
1. The utility model provides an electric energy meter terminal temperature detection circuit which characterized in that, electric energy meter terminal temperature detection circuit includes at least:
the terminal temperature detection module is used for detecting the temperature of the terminal of the electric energy meter and outputting a corresponding temperature voltage signal;
the temperature voltage signal processing module is connected to the output end of the terminal temperature detection module, amplifies the temperature voltage signal based on the value of the temperature voltage signal, converts the temperature voltage signal into a digital signal and then carries out digital processing;
the temperature and voltage signal processing module comprises an adjustable gain amplifier, a unit gain amplifier, a selector, an analog-to-digital converter and a digital processor;
the adjustable gain amplifier receives the temperature voltage signal and amplifies the temperature voltage signal;
the unit gain amplifier receives the temperature voltage signal and amplifies the temperature voltage signal;
the selector is connected with the output ends of the adjustable gain amplifier and the unit gain amplifier, and is used for selecting the output signal of the adjustable gain amplifier to output when the temperature voltage signal is smaller than a set value and selecting the output signal of the unit gain amplifier to output when the temperature voltage signal is larger than the set value;
the analog-to-digital converter is connected to the output end of the selector and is used for performing analog-to-digital conversion on the output signal of the selector;
the digital processor is connected with the output end of the analog-to-digital converter and the control end of the selector, processes the digital signal output by the analog-to-digital converter, and detects the amplitude of the digital signal to generate a selection control signal of the selector.
2. The electrical energy meter terminal temperature detection circuit of claim 1, wherein: the terminal temperature detection module comprises a temperature-sensitive resistor and a first resistor; the first end of the temperature-sensitive resistor is connected with a power supply voltage, the second end of the temperature-sensitive resistor is connected with the first end of the first resistor, and the second end of the first resistor is grounded; the first end of the first resistor outputs the temperature voltage signal.
3. The electrical energy meter terminal temperature detection circuit of claim 2, wherein: the terminal temperature detection module further comprises a second resistor; the second resistor is connected between the temperature sensitive resistor and the first resistor.
4. A circuit for detecting the temperature of a terminal of an electric energy meter according to claim 2 or 3, characterized in that: the terminal temperature detection module further comprises a filter capacitor; one end of the filter capacitor is connected with the first end of the first resistor, and the other end of the filter capacitor is grounded.
5. The electrical energy meter terminal temperature detection circuit of claim 1, wherein: the adjustable gain amplifier adopts fully differential input and output and inputs a high-impedance amplifier.
6. The electric energy meter terminal temperature detection circuit according to claim 1 or 5, wherein: the adjustable gain amplifier comprises a first operational amplifier, a third resistor, a fourth resistor, a fifth resistor and a sixth resistor; the first inverting input end of the first operational amplifier is connected with the output end of the terminal temperature detection module, and the first non-inverting input end of the first operational amplifier is grounded; the non-inverting output end of the first operational amplifier is connected with the second inverting input end of the first operational amplifier through the third resistor; the inverting output end of the first operational amplifier is connected with the second non-inverting input end of the first operational amplifier through the fourth resistor; the fifth resistor and the sixth resistor are connected in series and then connected between the second inverting input end and the second non-inverting input end of the first operational amplifier.
7. The electrical energy meter terminal temperature detection circuit of claim 1, wherein: the unit gain amplifier comprises a second operational amplifier, wherein the non-inverting input end of the second operational amplifier is connected with the output end of the terminal temperature detection module, and the inverting input end of the second operational amplifier is connected with the output end of the second operational amplifier.
8. The electrical energy meter terminal temperature detection circuit of claim 1, wherein: the analog-to-digital converter is a Sigma-Delta analog-to-digital converter.
9. The utility model provides a method for detecting the temperature of a terminal of an electric energy meter, which is characterized in that the method at least comprises the following steps:
detecting the temperature of a terminal of the electric energy meter, and obtaining a temperature voltage signal;
amplifying the temperature voltage signal by adopting an adjustable gain amplifier when the temperature voltage signal is smaller than a set value, and amplifying the temperature voltage signal by adopting a unit gain amplifier when the temperature voltage signal is larger than the set value;
and carrying out analog-to-digital conversion on the amplified temperature voltage signal to obtain a digital signal, and carrying out digital processing on the digital signal to obtain a temperature detection signal.
10. The method for detecting the temperature of the terminals of the electric energy meter according to claim 9, wherein: a fully differential input-output and high-impedance adjustable gain amplifier structure is adopted.
11. The method for detecting the temperature of the terminals of the electric energy meter according to claim 9, wherein: and detecting the amplitude of the digital signal during digital processing to judge the relation between the temperature voltage signal and the set value.
12. The electric energy meter terminal temperature detection method according to any one of claims 9 to 11, characterized in that: the amplification factor of the adjustable gain amplifier is 2, 4, 8 or 16 times.
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| CN101762335A (en) * | 2008-12-24 | 2010-06-30 | 精工电子有限公司 | Temperature detection circuit |
| CN101771428A (en) * | 2010-01-19 | 2010-07-07 | 青岛海信移动通信技术股份有限公司 | Temperature detection circuit and mobile communication equipment |
| JP2013096840A (en) * | 2011-11-01 | 2013-05-20 | Mitsubishi Electric Corp | Temperature detecting circuit and temperature detecting device |
| CN103335740A (en) * | 2013-06-28 | 2013-10-02 | 成都汉康信息产业有限公司 | Economic GPS telemetric terminal |
| CN108711835A (en) * | 2018-06-13 | 2018-10-26 | 方碧水 | A kind of line temperature detection device and application method |
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