WO2024040626A1

WO2024040626A1 - Temperature measurement method and apparatus based on synchronous detection

Info

Publication number: WO2024040626A1
Application number: PCT/CN2022/115795
Authority: WO
Inventors: 段宏宇; 徐怀明; 马清华
Original assignee: 北京华卓精科科技股份有限公司; 北京优微精密测控技术研究有限公司
Priority date: 2022-08-24
Filing date: 2022-08-30
Publication date: 2024-02-29
Also published as: CN117664383A

Abstract

A temperature measurement method and apparatus based on synchronous detection. The method comprises: acquiring an excitation signal and a measurement signal (S1); performing synchronous detection processing on the excitation signal and the measurement signal, so as to obtain a first direct-current component (S2); extracting the amplitude of the excitation signal, so as to obtain a second direct-current component (S3); according to the first direct-current component and the second direct-current component, determining a third direct-current component (S4); and according to the third direct-current component and the excitation signal, calculating a temperature value corresponding to the measurement signal (S5). In the temperature measurement method and apparatus based on synchronous detection, data which is passed back by a temperature measurement circuit is processed by using a synchronous detection principle, such that the impact of noise on a temperature signal can be better eliminated, and the impact of pulse noise and periodic noise on the temperature signal can be reduced, thereby measuring the temperature of the position of a temperature sensor in a complicated electromagnetic environment more accurately.

Description

Temperature measurement method and device based on synchronous detection

Cross-references to related applications

This application claims priority to the Chinese patent application with application number 2022110209874 and titled "Temperature Measurement Method and Device Based on Synchronous Detection" submitted to the China Patent Office on August 24, 2022, the entire content of which is incorporated into this application by reference. middle.

Technical field

This application relates to the technical field of temperature measurement, and specifically to a temperature measurement method and device based on synchronous detection.

Background technique

For environments with complex changes in the electromagnetic environment, to accurately measure temperature, the temperature sensor needs to be close to the measured object. However, the measured object is in a changing electromagnetic field. The temperature sensor cannot physically take measures such as isolation to reduce the alternating electromagnetic field. interference with its measurements. Relevant interference includes: (1) The temperature sampling circuit (sensor)'s own noise; (2) The induction effect of the alternating electromagnetic field within the environment on the temperature sensor. It can be seen that in the process of denoising the temperature signal, not only the influence of white noise must be considered, but also the influence of the temperature sensor in the alternating electromagnetic field environment needs to be considered. Therefore, it is very important to reduce the impact of environmental noise on the temperature signal.

In related technologies, most of the common temperature measurement circuits on the market currently use 3-wire or 4-wire systems, and require high-precision constant current power supplies. Complex constant-current source circuits need to be designed, and through strict circuit length, high-precision devices, Measures such as equal proportional resistance and capacitance reference values ensure strict matching of the output signal on the temperature sensor.

For example, the patent "Negative Feedback Closed-Loop AC Bridge Measurement Circuit" with application number 202022842826.6 and publication number CN213906628 discloses a temperature measurement device and temperature calculation method. This measurement method takes advantage of the advantages of the bridge and negative feedback circuit to suppress the signal channel. The quantization noise in the circuit improves the temperature measurement accuracy to a certain extent, but it requires higher accuracy of the signal source. The circuits include bridge circuits, detector circuits, integrating circuits and other related circuits. The board takes up a large space, has complex design and high cost. .

The patent "Temperature Measurement Device and Temperature Measurement Method" with application number 201010618396.8 and publication number CN102539001 discloses a temperature measurement device and temperature measurement method that automatically selects appropriate excitation constant current sources and precision references for different temperature sensors. Resistors reduce measurement errors to a certain extent, but high-precision constant current sources occupy a large space and require high-precision resistors, resulting in high cost and complicated design. Generally, the removal of temperature interference signals is achieved through hardware low-pass filtering, which is costly and cannot effectively remove the noise caused by temperature acquisition in complex electromagnetic environments.

Application content

In order to overcome the problems existing in the related art at least to a certain extent, the present application provides a temperature measurement method and device based on synchronous detection.

According to a first aspect of the embodiment of the present application, a temperature measurement method based on synchronous detection is provided, including:

Obtain excitation signals and measurement signals;

Perform synchronous detection processing on the excitation signal and the measurement signal to obtain the first DC component;

Extract the amplitude of the excitation signal to obtain the second DC component;

Determine the third DC component based on the first DC component and the second DC component;

The temperature value corresponding to the measurement signal is calculated based on the third DC component and the excitation signal.

Optionally, the excitation signal is a voltage signal generated by a signal generator, and the signal generator is controlled by a main control chip; the main control chip can directly obtain the excitation signal;

The excitation signal is applied to the temperature measurement circuit; the temperature measurement circuit includes a temperature sensor; and the measurement signal is the measured voltage signal at both ends of the temperature sensor.

Optionally, performing synchronous detection processing on the excitation signal and the measurement signal includes:

Multiply the excitation signal and the measurement signal to obtain a superimposed signal;

A low-pass filter is used to filter the superimposed signal to obtain the first DC component.

Optionally, the excitation signal is recorded as y=Asin2πf _m t; the measurement signal is recorded as p=Bsin2πf _m t;

Among them, A is the amplitude of the excitation signal, f _m is the frequency of the excitation signal, A and f _m are both known quantities; B is the amplitude of the measurement signal.

Optionally, the amplitude A and frequency f _m of the excitation signal can be changed through the control of the main control chip.

Optionally, the superimposed signal is:

The first DC component is:

Optionally, determining the third DC component based on the first DC component and the second DC component includes:

The third DC component=2×the first DC component÷the second DC component.

Optionally, calculating the temperature value corresponding to the measurement signal based on the third DC component and the excitation signal includes:

Use the third DC component as the amplitude of the corrected measurement signal to reconstruct the corrected measurement signal;

Input the excitation signal and the corrected measurement signal into a preset resistance calculation model to obtain the resistance value of the temperature sensor;

Query the temperature-resistance correspondence relationship of the temperature sensor based on the resistance value to determine the detected temperature value.

Optionally, the resistance calculation model is:

Among them, U _ref is the excitation signal, U _ntc is the corrected measurement signal, R _n is the fixed resistance value in series with the temperature sensor, K = U _ref /U _ntc .

According to a second aspect of the embodiment of the present application, a temperature measurement device based on synchronous detection is provided, including:

an acquisition module configured to acquire the excitation signal and the measurement signal;

A synchronous detection module configured to perform synchronous detection processing on the excitation signal and the measurement signal to obtain the first DC component;

An extraction module configured to extract the amplitude of the excitation signal to obtain the second DC component;

a determining module configured to determine the third DC component based on the first DC component and the second DC component;

A solution module configured to calculate the temperature value corresponding to the measurement signal according to the third DC component and the excitation signal.

The technical solutions provided by the embodiments of this application have the following beneficial effects:

The solution of this application provides a more efficient and convenient noise processing method. It uses the principle of synchronous detection to process the data returned by the temperature measurement circuit, which can better eliminate the impact of noise on the temperature signal and reduce pulse noise and periodic noise. The influence on the temperature signal can more accurately measure the temperature at the location of the temperature sensor in a complex electromagnetic environment; the circuit design of this solution is simple, suitable for scenarios with limited circuit board space and strict cost requirements, and can accurately and efficiently detect interference environments in real time. Perform fast and efficient calculations based on temperature measurements.

It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and do not limit the present application.

Description of drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the application and together with the description, explain the principles of the application.

FIG. 1 is a flow chart of a temperature measurement method based on synchronous detection according to an exemplary embodiment.

FIG. 2 is a circuit diagram of an application scenario of a temperature measurement method based on synchronous detection according to an exemplary embodiment.

Figure 3 is a circuit schematic diagram of the temperature measurement circuit in the circuit shown in Figure 3.

FIG. 4 is a flow chart of an algorithm for reducing temperature signal noise according to an exemplary embodiment.

Figure 5 is a schematic diagram of a noise reduction algorithm configured to measure the temperature of a coarse motion motor according to an embodiment of the present application.

Figure 6a is the resistance value collected by the temperature channel before noise reduction in Embodiment 1.

Figure 6b shows the resistance value collected by the temperature channel after noise reduction in Embodiment 1.

Figure 7 is a schematic diagram of a noise reduction algorithm configured to measure the temperature of a micromotor according to an embodiment of the present application.

Detailed ways

Exemplary embodiments will be described in detail herein, examples of which are illustrated in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings refer to the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with this application. Rather, they are merely examples of methods and apparatus consistent with certain aspects of the application as detailed in the appended claims.

In order to measure the temperature of equipment working in an alternating electromagnetic environment, the temperature sensor needs to be close to the object being measured; in this way, in the alternating electromagnetic field, the temperature sensor, in addition to testing the temperature, also induces the alternating electromagnetic field, producing an alternating induced voltage. (current), for temperature measurement, this induced voltage (or current) is noise. Affected by the alternating electromagnetic field, the temperature voltage value measured by the temperature sensor changes greatly. The noise in the signal collected by some temperature sensors can even completely cover the temperature information. In order to accurately and efficiently measure the temperature around the motor, the signals collected by the temperature sensor need to be processed for noise reduction.

Two types of noise are introduced during the temperature measurement process: environmental noise and sensor own noise. Common methods to eliminate noise in temperature signals include finite-amplitude filtering, composite digital filtering that combines median filtering and wavelet threshold filtering, and moving average filtering. These algorithms cannot take into account the two kinds of noise existing in the motor temperature measurement system at the same time and require more core resources when used. Therefore, this application combines the synchronous detection principle with the temperature measurement principle to propose a new algorithm suitable for the motor temperature measurement system. Algorithm for reducing temperature signal noise.

FIG. 1 is a flow chart of a temperature measurement method based on synchronous detection according to an exemplary embodiment. The method may include the following steps:

Step S1: Obtain the excitation signal and measurement signal;

Step S2: Perform synchronous detection processing on the excitation signal and the measurement signal to obtain the first DC component;

Step S3: Extract the amplitude of the excitation signal to obtain the second DC component;

Step S4: Determine the third DC component based on the first DC component and the second DC component;

Step S5: Calculate the temperature value corresponding to the measurement signal based on the third DC component and the excitation signal.

It should be understood that although various steps in the flowchart of FIG. 1 are shown in sequence as indicated by arrows, these steps are not necessarily executed in the order indicated by arrows. Unless explicitly stated in this article, there is no strict order restriction on the execution of these steps, and these steps can be executed in other orders. Moreover, at least some of the steps in Figure 1 may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but may be executed at different times. The execution of these sub-steps or stages The sequence is not necessarily sequential, but may be performed in turn or alternately with other steps or sub-steps of other steps or at least part of the stages.

In order to further describe the technical solution of this application, the application environment of this solution is first introduced.

The denoising method of this application can be applied to temperature measurement devices based on excitation signals. In some embodiments, the temperature measurement device may have a structure as shown in FIG. 2 . The device includes: a controller, a signal generator, a temperature measurement circuit, a conditioning circuit and a signal sampling circuit; the temperature measurement circuit includes a temperature sensor and a voltage dividing resistor connected in series.

The controller is configured to control the reference signal generator to output an excitation signal, and the excitation signal is applied to both ends of the temperature measurement circuit; the conditioning circuit is configured to collect the divided voltage at both ends of the temperature sensor, and divide the voltage into The voltage is conditioned and then output to the signal sampling circuit. The controller obtains the divided voltage and the excitation signal from the signal sampling circuit, and calculates the temperature value detected by the temperature sensor based on the divided voltage, the excitation signal voltage and the resistance value of the voltage dividing resistor.

In some embodiments, the excitation signal is a voltage signal generated by a signal generator, and the signal generator is controlled by a main control chip; the main control chip can directly obtain the excitation signal;

Based on the above hardware circuit, the temperature measurement principle of this solution is introduced in detail below.

As shown in Figure 3, the excitation signal is generated by the DA chip under the control of the main control chip to generate the required excitation modulation signal. After passing through the conditioning circuit, the signal is output to the AD sampling chip for collection, which is recorded as U _ref ; at the same time, the excitation signal is added to the The two ends of the series circuit composed of the voltage dividing resistors R ₁ and R ₂ and the temperature sensor. The temperature sensor obtains the voltage through the voltage dividing network. After passing through the op amp amplification circuit, it is output to the AD sampling chip through the conditioning circuit to obtain K ₁ ×U _ntc . The AD sampling chip, under the control of the main control chip, simultaneously samples the amplified and conditioned signals of the excitation signal and the temperature sensor's voltage division signal. The main control chip obtains a high-precision temperature sensor voltage division signal through calculation, and then finds the corresponding temperature-resistance of the temperature sensor. Curve, a high-precision temperature measurement signal can be obtained. The calculation principle of the main control chip is as follows:

U _ref is the signal collected by the AD after the excitation signal output by the main control chip passes through the conditioning circuit; U _ntc is the temperature signal collected by the AD chip after the temperature sensor outputs the conditioning circuit; R _ntc is the temperature sensor, R ₁ and R ₂ is a voltage dividing resistor, connected in series across both ends of R _ntc . Through the partial pressure formula, we can get:

In formula (1), only R _ntc is an unknown quantity. The calculation formula of R _ntc can be obtained as follows:

According to the solved R _ntc , find the temperature-resistance curve corresponding to the temperature sensor to get the actual temperature value.

For high-precision temperature testing in small spaces, it can be seen from Equation (2) and Figure 4 that U _ntc is generated by U _ref partial pressure, that is, it has a certain proportional relationship, that is, U _ref can be approximated as KR _ntc , such that (2) can be simplified to:

It can be seen from equation (3) that the resistance measurement accuracy of the temperature measurement circuit based on the excitation signal is only related to the voltage dividing resistors R ₁ and R ₂ and the ratio of the voltage dividing circuit, and has nothing to do with other factors. Therefore, the measurement accuracy of this application does not rely on a high-precision constant current source, which can greatly simplify circuit design and reduce circuit costs.

In some embodiments, the reference signal generator can provide a variety of excitation signals, including sinusoidal signals and square wave signals. It can be seen from formula (2) that the excitation signal U _ntc can be an arbitrary waveform, including DC signals; using DC excitation can simplify the design, but it cannot distinguish between temperature drift, offset voltage and useful signals, resulting in a decrease in measurement accuracy; while alternating waveforms can effectively To eliminate the effects of temperature drift and offset voltage, the alternating waveform is preferred as the excitation signal.

It should be noted that if the detected measurement signal is directly used and substituted into formula (3) to calculate the resistance value of the temperature sensor, then the noise signal that may be included in the measurement signal will be ignored, which will affect the final measurement accuracy. . In the solution of this application, noise refers to other signals that interfere with the temperature signal. Filtering is the operation of filtering out specific frequency bands in signals and is an important measure to suppress and prevent interference. Low-pass filter is a filtering method. The rule is that low-frequency signals can pass normally, while high-frequency signals that exceed the set threshold are blocked and weakened.

In order to further improve the accuracy of temperature measurement, in the method of this application, it is necessary to first perform denoising through steps S1 to S4 to obtain the denoised partial pressure signal on the temperature sensor; and then solve the resistance value of the temperature sensor through step S5. , so that the final result can be more accurate.

As shown in Figure 4, the solution of this application will be expanded and explained below based on specific application scenarios.

Assume that the excitation signal U _ref is a sine wave emitted by the main control chip controlling the DA chip, which can be recorded as y=Asin2πf _m t; since the excitation signal is generated by the main control chip control signal generator (DA), the amplitude of the excitation signal The value A and frequency f _m are known and can be changed through the control of the main control chip. For the process shown in Figure 4, the size and frequency are known and can be changed by modifying the program.

The measurement signal U _ntc is the voltage signal at both ends of the temperature sensor collected by the temperature measurement circuit, which can be recorded as p=Bsin2πf _m t, where B is the amplitude of the measurement signal. The corresponding relationship between the excitation signal and the measurement signal is determined by the temperature measurement circuit.

Use the excitation signal, calculate the resistance value after completing low-pass filtering, and then determine the temperature. The excitation signal is sent by the FPGA and noise is reduced through the synchronous detection algorithm; low-pass filtering is a step in the synchronous detection algorithm.

In some embodiments, performing synchronous detection processing on the excitation signal and the measurement signal includes:

According to the principle of synchronous detection, the excitation signal and the measurement signal are multiplied, that is, the superimposed signal is:

The result obtained can be regarded as the superposition of the DC signal and the high-frequency AC signal. Just use a low-pass filter to filter out the high-frequency signal, and the DC signal (first DC component) can be obtained as:

The second DC component is the amplitude A of the excitation signal, which is a known quantity; thus the amplitude of the corrected measurement signal (ie, the third DC component) can be calculated:

The third DC component = 2×the first DC component÷the second DC component;

Then the excitation signal and the corrected measurement signal are input into the resistance calculation model, and the resistance of the temperature measuring resistor can be calculated. Finally, the current ambient temperature can be obtained by using the look-up table method according to the characteristic curve of the temperature measuring resistor.

Embodiment 1: Measurement and calculation of temperature signal of coarse motion motor of double workpiece stage

As shown in Figure 5, the detailed implementation process of this embodiment:

For motor temperature measurement, it is the best way to monitor the work of the motor on the double workpiece table. When the motor is working, there are alternating electric and magnetic fields near its coils. The environment changes frequently and randomly, which is a good way to accurately monitor the surroundings of the coarse-moving motor. For the temperature of the environment, a temperature sensor is placed close to the coarse motion motor. The temperature signal collected by the temperature sensor is transmitted to the temperature sampling circuit in the form of voltage. The temperature signal after passing through the sampling circuit is transmitted as input to the noise reduction algorithm for processing to obtain the temperature value. , and finally transmit the temperature value to the host computer. Thus, the temperature value calculated by the test can be directly fed back to the working status of the motor.

As shown in Embodiment 1: In order to accurately monitor the temperature of the environment around the coarse motion motor, a temperature sensor is placed immediately adjacent to the coarse motion motor. The temperature sensor placed in this embodiment is an NTC temperature measuring resistor; the temperature collected by the temperature measuring resistor The signal is transmitted to the temperature measurement circuit in the form of a voltage signal, and the sampled temperature signal is transmitted to the host computer; the sampled temperature signal is used as the input of the synchronous detection and noise reduction algorithm, and is denoised in the host computer algorithm; the denoised temperature signal Enter the table lookup algorithm to calculate the real-time temperature value. The final temperature value is displayed and processed by the host computer and the next step is processed.

Based on Embodiment 1, the test data results are shown in Figure 6. The standard deviation of the temperature channel resistance value of the coarse motion motor before noise reduction is: 470.235; the standard deviation of the temperature channel resistance value of the coarse motion motor after noise reduction (after the system is stabilized) is 0.0583. Can meet actual temperature testing needs.

Embodiment 2: Noise reduction of temperature signal of micro-motor on dual workpiece stages of photolithography machine

As shown in Figure 7, the detailed implementation process of this embodiment:

In order to accurately monitor the temperature of the environment around the micromotor, a temperature sensor is placed close to the micromotor. The temperature signal collected by the temperature sensor is transmitted to the temperature sampling circuit in the form of voltage. The temperature signal after passing through the sampling circuit is transmitted as input to The noise reduction algorithm performs processing to obtain the temperature value, and finally the temperature value is transmitted to the host computer.

In order to accurately monitor the temperature of the environment around the micro-motor, a temperature sensor is placed immediately adjacent to the coarse-motor motor. In this embodiment, the temperature sensor placed is an NTC temperature measuring resistor; the temperature signal collected by the temperature measuring resistor is transmitted in the form of a voltage signal. to the temperature measurement circuit, the sampled temperature signal is obtained; the sampled temperature signal is used as the input of the synchronous detection and noise reduction algorithm, and is denoised in the main control chip; the denoised temperature signal enters the lookup table algorithm to calculate the real-time temperature value. Finally, the temperature value is transmitted to the host computer.

An embodiment of the present application also provides a temperature measurement device based on synchronous detection, including:

Regarding the devices in the above embodiments, the specific steps for each module to perform operations have been described in detail in the embodiments related to the method, and will not be described in detail here. Each module in the above-mentioned temperature measurement device can be implemented in whole or in part by software, hardware and combinations thereof. Each of the above modules can be embedded in or independent of the processor of the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the operations corresponding to each of the above modules.

It can be understood that the same or similar parts in the above-mentioned embodiments can be referred to each other, and the content that is not described in detail in some embodiments can be referred to the same or similar content in other embodiments.

It should be noted that in the description of this application, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. Furthermore, in the description of this application, unless otherwise stated, the meaning of "plurality" means at least two.

Any process or method descriptions in flowcharts or otherwise described herein may be understood to represent modules, segments, or portions of code that include one or more executable instructions for implementing the specified logical functions or steps of the process. , and the scope of the preferred embodiments of the present application includes additional implementations in which functions may be performed out of the order shown or discussed, including in a substantially simultaneous manner or in the reverse order, depending on the functionality involved, which shall It should be understood by those skilled in the technical field to which the embodiments of this application belong.

It should be understood that various parts of the present application can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, various steps or methods may be implemented in software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if it is implemented in hardware, as in another embodiment, it can be implemented by any one or a combination of the following technologies known in the art: a logic gate circuit configured to implement a logical function for a data signal; Discrete logic circuits, application specific integrated circuits with suitable combinational logic gates, programmable gate arrays (PGA), field programmable gate arrays (FPGA), etc.

Those of ordinary skill in the art can understand that all or part of the steps involved in implementing the methods of the above embodiments can be completed by instructing relevant hardware through a program. The program can be stored in a computer-readable storage medium. The program can be stored in a computer-readable storage medium. When executed, one of the steps of the method embodiment or a combination thereof is included.

In addition, each functional unit in various embodiments of the present application can be integrated into a processing module, or each unit can exist physically alone, or two or more units can be integrated into one module. The above integrated modules can be implemented in the form of hardware or software function modules. If the integrated module is implemented in the form of a software function module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

The storage media mentioned above can be read-only memory, magnetic disks or optical disks, etc.

In the description of this specification, reference to the terms "one embodiment," "some embodiments," "an example," "specific examples," or "some examples" or the like means that specific features are described in connection with the embodiment or example. , structures, materials or features are included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although the embodiments of the present application have been shown and described above, it can be understood that the above-mentioned embodiments are illustrative and cannot be understood as limitations of the present application. Those of ordinary skill in the art can make modifications to the above-mentioned embodiments within the scope of the present application. The embodiments are subject to changes, modifications, substitutions and variations.

Industrial applicability

The use of the principle of synchronous detection provided by the embodiments of this application to process the data returned by the temperature measurement circuit can better eliminate the impact of noise on the temperature signal, reduce the impact of pulse noise and periodic noise on the temperature signal, and provide more accurate Measure the temperature at the location of the temperature sensor in a complex electromagnetic environment; the circuit design of this solution is simple, suitable for scenarios with limited circuit board space and strict cost requirements, and can accurately and efficiently calculate temperature measurements in interference environments in real time. , has significant economic benefits.

Claims

A temperature measurement method based on synchronous detection, which is characterized by including:

Obtain excitation signals and measurement signals;

Perform synchronous detection processing on the excitation signal and the measurement signal to obtain the first DC component;

Extract the amplitude of the excitation signal to obtain the second DC component;

Determine the third DC component based on the first DC component and the second DC component;

The temperature value corresponding to the measurement signal is calculated based on the third DC component and the excitation signal.
The method according to claim 1, characterized in that the excitation signal is a voltage signal generated by a signal generator, and the signal generator is controlled by a main control chip; the main control chip can directly obtain the excitation signal;

The excitation signal is applied to the temperature measurement circuit; the temperature measurement circuit includes a temperature sensor; and the measurement signal is the measured voltage signal at both ends of the temperature sensor.
The method according to claim 2, characterized in that, performing synchronous detection processing on the excitation signal and the measurement signal includes:

Multiply the excitation signal and the measurement signal to obtain a superimposed signal;

A low-pass filter is used to filter the superimposed signal to obtain the first DC component.
The method according to claim 3, characterized in that the excitation signal is marked as y=Asin2πf mt ; the measurement signal is marked as p=Bsin2πf mt ;

Among them, A is the amplitude of the excitation signal, f m is the frequency of the excitation signal, A and f m are both known quantities; B is the amplitude of the measurement signal.
The method according to claim 4, characterized in that the amplitude A and frequency fm of the excitation signal can be changed through the control of a main control chip.
The method according to claim 4, characterized in that the superimposed signal is:

The first DC component is:
The method of claim 6, wherein determining the third DC component according to the first DC component and the second DC component includes:

The third DC component=2×the first DC component÷the second DC component.
The method according to any one of claims 1 to 7, characterized in that, calculating the temperature value corresponding to the measurement signal based on the third DC component and the excitation signal includes:

Use the third DC component as the amplitude of the corrected measurement signal to reconstruct the corrected measurement signal;

Input the excitation signal and the corrected measurement signal into a preset resistance calculation model to obtain the resistance value of the temperature sensor;

Query the temperature-resistance correspondence relationship of the temperature sensor based on the resistance value to determine the detected temperature value.
The method according to claim 8, characterized in that the resistance calculation model is:

Among them, U ref is the excitation signal, U ntc is the corrected measurement signal, R n is the fixed resistance value in series with the temperature sensor, K = U ref /U ntc .
A temperature measurement device based on synchronous detection, which is characterized by including:

an acquisition module configured to acquire the excitation signal and the measurement signal;

A synchronous detection module configured to perform synchronous detection processing on the excitation signal and the measurement signal to obtain the first DC component;

An extraction module configured to extract the amplitude of the excitation signal to obtain the second DC component;

a determining module configured to determine the third DC component based on the first DC component and the second DC component;

A solution module configured to calculate the temperature value corresponding to the measurement signal according to the third DC component and the excitation signal.