Low-frequency temperature noise active suppression method based on phase compensation and feedback correction

Abstract

The invention provides a low-frequency temperature noise active suppression method based on phase compensation and feedback correction. The method comprises the steps that S1, input heat flow generated by an external heat source is collected in real time; s2, performing spectral analysis on the input heat flow, analyzing the noise power spectral density or amplitude spectral density of the input heat flow, selecting a frequency needing to be compensated, and reducing the input heat flow through inverse Fourier transform in combination with frequency domain characteristics to obtain a branch heat flow of the corresponding frequency needing to be compensated in the input heat flow; s3, corresponding compensation heat flow is calculated according to the heat flow needing to be reduced in combination with the heat transfer-phase delay-amplitude attenuation characteristics during heat conduction of the low-frequency periodic heat flow; and S4, corresponding the compensation heat flow according to the corresponding branch heat flow, inputting the compensation heat flow into the input heat flow for feedback correction, and completing temperature noise suppression after the phase compensation heat flow is input. The compensation heat flow precision is improved, the temperature noise suppression effect is enhanced, and the temperature stability and the measurement precision are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of temperature noise control, and particularly relates to a low-frequency temperature noise active suppression method based on phase compensation and feedback correction. BACKGROUND

[0002] In today's scientific research, industrial production, and aerospace and many other fields, the application of precision instruments is becoming more and more widespread. These precision instruments often have high-precision measurement, analysis and calculation capabilities, and can provide key data support for scientific research and production. However, their performance and measurement accuracy are easily affected by temperature changes. For example, in the field of spaceborne precision optical instruments in aerospace, even a small fluctuation in temperature can cause thermal deformation of optical elements, thereby affecting imaging quality and measurement accuracy; in high-precision laboratory measuring instruments, temperature noise will interfere with the normal operation of the sensor, causing measurement results to deviate. Therefore, ensuring the temperature stability of the working environment of precision instruments is crucial to their performance.

[0003] During the operation of precision instruments, they are inevitably affected by heat flow from the surrounding environment. Among them, low-frequency heat flow noise, due to its long duration, slow fluctuation and difficulty in natural dissipation, becomes a key factor affecting the temperature stability of precision instruments. Low-frequency heat flow noise can be caused by various factors, such as periodic changes in environmental temperature. These low-frequency heat flow noises will cause fluctuations in the internal temperature of the precision instrument, forming temperature noise. When the temperature noise exceeds a certain range, it will seriously reduce the measurement accuracy and reliability of the precision instrument, and cannot meet the demand for high-precision measurement in modern scientific research and industrial production.

[0004] Currently, the methods for temperature control and noise suppression of precision instruments mainly include passive thermal control and active thermal control. Passive thermal control methods, such as the use of thermal insulation materials and thermal control coatings, can reduce the entry of external heat flow to some extent, but have limited effect on temperature noise suppression caused by low-frequency heat flow noise and cannot actively respond to dynamic changes in heat flow. Traditional active thermal control methods are mostly based on feedback of temperature changes for adjustment. Due to the hysteresis of temperature itself, these methods have time delay, weak adjustment ability and low efficiency, and are difficult to effectively suppress temperature noise caused by low-frequency heat flow noise. SUMMARY

[0005] The present application aims to provide a low-frequency temperature noise active suppression method based on phase compensation and feedback correction, to solve the problem that passive thermal control methods in the prior art have limited effect on temperature noise suppression caused by low-frequency heat flow noise and cannot actively respond to dynamic changes in heat flow, and traditional active thermal control methods have time delay, weak adjustment ability and low efficiency, and are difficult to effectively suppress temperature noise caused by low-frequency heat flow noise.

[0006] The application provides a low-frequency temperature noise active suppression method based on phase compensation and feedback correction, which is realized by using a noise active suppression structure and is used for suppressing temperature noise in a wide frequency band. The method comprises the following steps: S1, collecting input heat flow generated by an external heat source in real time; S2, performing spectrum analysis on the input heat flow, analyzing noise power spectral density or amplitude spectral density of the input heat flow, selecting a frequency which needs to be compensated, and combining frequency domain characteristics to perform reduction on the input heat flow by using inverse Fourier transform, so as to obtain a partial heat flow corresponding to the frequency which needs to be compensated in the input heat flow; S3, calculating a corresponding compensation heat flow according to the heat flow which needs to be reduced and heat transfer-phase delay-amplitude attenuation characteristics of low-frequency periodic heat flow heat conduction; S4, feeding back the compensation heat flow to the input heat flow according to the corresponding partial heat flow for feedback correction, and completing temperature noise suppression after the input phase compensation heat flow.

[0007] Preferably, the step S3 comprises the following steps: performing compensation heat flow calculation based on the partial heat flow; reducing the input heat flow Q in : The noise amplitude spectral density ASD Q of the input heat flow is obtained by spectrum analysis, the heat flow which needs to be compensated is selected, amplitude attenuation δ(f) and phase delay τ(f) characteristics of the heat flow are calculated according to the selected frequency f, and the heat flow Q′ in : The amplitude after attenuation and the phase after delay of the partial heat flow when the partial heat flow is transferred to the compensation interface are calculated according to the heat flow which needs to be reduced and heat transfer-phase delay-amplitude attenuation characteristics of low-frequency periodic heat flow heat conduction, the phase of the compensation heat flow is about 180° (π) different from the phase of the input heat flow when the input heat flow is transferred to the compensation interface. The compensation heat flow obtained according to the criterion is as follows: Considering bidirectional propagation of the heat flow, the amplitude of the final compensation heat flow is about twice the amplitude of the heat flow after attenuation: B c，i = 2Bi; the final compensation heat flow is obtained as follows: Wherein, the sum of A′ and B c，i ; the voltage of the corresponding compensation heat flow is output by controlling the voltage signal, and the compensation heat flow is output by the heater.

[0008] Preferably, the step S4 comprises the following steps: collecting heat flow data Q M1 of the controlled part after phase compensation by using a heat flux sensor at the controlled part; and adjusting the phase and amplitude of the compensation heat flow by using feedback correction method based on the heat flow data Q M , Q M1 of the controlled part before and after compensation. The feedback correction method is as follows: the heat flow of the controlled part after phase compensation is jointly influenced by the compensation heat flow and the input heat flow. The part influenced by the compensation heat flow is denoted as QM2 , the calculation formula is: Q M2 = Q M - Q M1 ; compare the amplitude and phase of Q M1 and Q M2 , according to the amplitude and phase difference, increase or decrease the amplitude and phase, according to the adjusted amplitude and phase, control the voltage signal output to adjust the corresponding compensating heat flow voltage, and output the adjusted compensating heat flow from the heater.

[0009] Preferably, the noise active suppression structure comprises passive thermal control material, a plurality of heat flux sensors, a plurality of compensating heat flow heater devices and a controller; a plurality of the heat flux sensors and a plurality of the compensating heat flow heater devices are one-to-one corresponding, and each of the heat flux sensors is connected with the controller and the corresponding compensating heat flow heater device respectively.

[0010] Preferably, the heat flux sensor is arranged on the side of the passive thermal control material facing the heat source; the compensating heat flow heater device is arranged in the passive thermal control material and close to the front half of the heat source.

[0011] Preferably, the feedback correction method adjusts the phase and amplitude of the compensating heat flow on the basis of phase compensation; and when the feedback correction adjustment of the compensating heat flow is performed, the data before and after compensation should start at the same time, and the phase of the input heat flow at the time after compensation should be the same as before compensation, and the length of the time period taken is the length of the corresponding frequency period.

[0012] Preferably, the rules of increasing or decreasing the phase and amplitude are as follows: first adjust the phase, then adjust the amplitude, and only one parameter is adjusted each time. If the phase of Q M2 is less than the phase of Q M1 , the phase of Q M2 needs to be increased, and the increase amplitude is the absolute value of the phase difference between Q M2 and Q M1 . When the absolute value of the position difference between the minimum value of Q M2 and the maximum value of Q M1 is less than 1 / 500 of the period, it can be considered that the phase adjustment is completed. Then the amplitude adjustment is performed. If the absolute value of the extreme value of Q M2 is greater than the absolute value of the extreme value of Q M1 , the amplitude needs to be decreased; if the absolute value of the extreme value of Q M2 is less than the absolute value of the extreme value of Q M1 , the amplitude needs to be increased. The increase or decrease amplitude is the difference ΔB M2 between the absolute value of the extreme value of Q M1 and the absolute value of the extreme value of Q M . M .

[0013] Preferably, the wide frequency band is a frequency band less than 0.1 Hz.

[0014] Preferably, for the multi-frequency composite heat flow, Q M , Q M1 , Q M2 Frequency domain analysis is needed by Fourier transform decomposition, and component single frequency heat flow restoration is needed by inverse Fourier transform, and then phase and amplitude adjustment of the compensation heat flow is needed by feedback correction method.

[0015] The low-frequency temperature noise active suppression method based on phase compensation and feedback correction of the application has the following advantages:

[0016] Active external heat flow phase compensation control is mainly used, real-time acquisition of external input heat flow is performed, spectrum analysis and heat flow restoration are performed, compensation heat flow is calculated combining with low-frequency periodic heat flow heat transfer characteristics, and the compensation heat flow is converted into a voltage signal to control the output power of a heat compensation device, so as to perform phase compensation on the input heat flow, thereby effectively suppressing the temperature noise caused by low-frequency heat flow noise, and the feedback correction method of the compensation heat flow is added on the basis of the phase compensation method, so as to improve the compensation heat flow accuracy, enhance the temperature noise suppression effect, improve the temperature stability and measurement accuracy of the precision instrument, and meet the higher requirements of modern science and technology on the performance of the precision instrument. BRIEF DESCRIPTION OF DRAWINGS

[0017] The accompanying drawings are included to provide a further understanding of the application, and constitute a part of the specification, and are used together with embodiments of the application to explain the application, and do not constitute a limitation on the application. In the drawings:

[0018] Figure 1 A flowchart of the low-frequency temperature noise active suppression method based on phase compensation and feedback correction in the application is shown.

[0019] Figure 2 A structure conceptual diagram of the low-frequency temperature noise active suppression method based on phase compensation and feedback correction in the application is shown.

[0020] Figure 3 A comparison diagram of the compensation heat flow and the input heat flow transferred to the heat flow at the compensation interface in the application is shown.

[0021] Figure 4 A heat transfer amplitude attenuation characteristic diagram of the low-frequency periodic heat flow in the application is shown.

[0022] Figure 5 A comparison diagram of the heat flow data Q M2 and Q M1 before and after phase compensation of the controlled part in the application is shown.

[0023] Figure 6 The diagram shows the heat transfer phase delay time characteristics of low-frequency periodic heat flow in this invention.

[0024] Figure 7 This is a comparison diagram of temperature fluctuations in the controlled part before and after phase compensation in this invention.

[0025] Figure 8 The image shows a comparison of the temperature noise amplitude spectral density of the controlled part before and after phase compensation in this invention.

[0026] Figure 9 The image shows a comparison of the temperature noise amplitude spectral density of the controlled part before and after phase compensation and after feedback correction in this invention.

[0027] Figure 10 The image shows a comparison of the temperature noise amplitude spectral density of the controlled part before and after phase compensation and after feedback correction when the input heat flow is a random three-frequency heat flow in this invention. Detailed Implementation

[0028] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0029] like Figures 1 to 10 As shown, this invention provides a method for active suppression of low-frequency temperature noise based on phase compensation and feedback correction. It employs an active noise suppression structure and is used to suppress temperature noise over a wide frequency band. The method includes the following steps: S1, real-time acquisition of the input heat flow generated by an external heat source; S2, spectral analysis of the input heat flow to analyze its noise power spectral density or amplitude spectral density, selecting the frequencies requiring compensation, and using inverse Fourier transform to reconstruct the input heat flow based on its frequency domain characteristics, obtaining the corresponding frequency-specific heat flow requiring compensation; S3, calculating the corresponding compensation heat flow based on the reconstructed heat flow and the heat transfer-phase delay-amplitude attenuation characteristics of low-frequency periodic heat flow; S4, inputting the compensation heat flow, after corresponding to the specific heat flow, into the input heat flow for feedback correction. After inputting the phase-compensated heat flow, temperature noise suppression is completed. In a preferred embodiment, step S3 includes: calculating the compensation heat flow based on the specific heat flow; the reconstructed input heat flow Q... in : The noise amplitude spectral density (ASD) of the input heat flux is obtained through spectral analysis. Q Select the heat flux that needs compensation, and calculate the amplitude attenuation δ(f) and phase delay τ(f) characteristics of the heat flow at that frequency based on the selected frequency f. Calculate the heat flux Q′ when the heat flux is transferred to the compensation interface. in : According to the heat transfer-phase delay-amplitude attenuation characteristics of the heat flow to be reduced combined with the heat conduction of the low frequency periodic heat flow, the amplitude and the delayed phase of the heat flow after attenuation when the heat flow is transmitted to the compensation interface are calculated, and the phase difference between the compensation heat flow and the phase of the input heat flow transmitted to the compensation interface is about 180°(π). The compensation heat flow obtained according to the criterion is: Considering the bidirectional propagation of the heat flow, the amplitude of the final compensation heat flow is about twice the amplitude of the attenuated heat flow: B c，i = 2B i ; and the final compensation heat flow is obtained: Wherein, A' > B c，i ; the voltage of the corresponding compensation heat flow is output by controlling the voltage signal, and the compensation heat flow is output by the heater. The step S4 comprises: collecting the heat flow data Q M1 of the controlled part after phase compensation by the heat flux sensor at the controlled part; and taking the heat flow data Q M , Q M1 before and after compensation of the controlled part as the basis, the phase and amplitude of the compensation heat flow are adjusted by the feedback correction method. The feedback correction method is as follows: the heat flow of the controlled part after phase compensation is jointly affected by the compensation heat flow and the input heat flow. The part affected by the compensation heat flow is denoted as Q M2 , and the calculation formula is: Q M2 = Q M -Q M1 ; by comparing the amplitude and phase of Q M1 and Q M2 , the amplitude and phase are increased or decreased according to the amplitude and phase difference, the voltage of the corresponding compensation heat flow is output by controlling the voltage signal according to the adjusted amplitude and phase, and the adjusted compensation heat flow is output by the heater. The active noise suppression structure comprises passive thermal control materials, a plurality of heat flux sensors, a plurality of compensation heat flow heater devices and a controller; the plurality of heat flux sensors and the plurality of compensation heat flow heater devices are one-to-one corresponding, and each heat flux sensor is respectively connected with the controller and the corresponding compensation heat flow heater device. The heat flux sensor is arranged on the side of the passive thermal control material facing the heat source; the compensation heat flow heater device is arranged in the passive thermal control material and close to the front half of the heat source. The feedback correction method adjusts the phase and amplitude of the compensation heat flow on the basis of phase compensation; and when the feedback correction adjustment of the compensation heat flow is performed, the data before and after compensation should start at the same time, the phase of the input heat flow at the time after compensation should be the same as before compensation, and the length of the taken time period is the length of the corresponding frequency period. The rules of increasing or decreasing the phase and amplitude are as follows: first adjust the phase, then adjust the amplitude, and only one parameter is adjusted each time. If the phase of Q M2 is less than the phase of Q M1 , the phase of Q M2 needs to be increased, and the increase amplitude is QM2 Q M1 absolute value of phase difference Q M2 absolute value of minimum M1 absolute value of position difference of maximum is less than 1 / 500 of period, it can be considered that phase adjustment is completed. Subsequently, amplitude adjustment is performed. If absolute value of extreme value of Q M2 is greater than absolute value of extreme value of Q M1 , amplitude needs to be reduced; if absolute value of extreme value of Q M2 is less than absolute value of extreme value of Q M1 , amplitude needs to be increased. Increase or decrease amplitude is difference ΔB M2 between absolute value of extreme value of Q M1 and absolute value of extreme value of Q M . Absolute value of ΔB M is |ΔB M |. The wide frequency band is a frequency band less than 0.1 Hz. Similarly, the feedback correction method focuses on a lower frequency part in the target frequency band. In addition, for a multi-frequency composite heat flow, Q M , Q M1 , Q M2 need to be analyzed in frequency domain through Fourier transform decomposition, and then the phase and amplitude of the compensation heat flow are adjusted through inverse Fourier transform and feedback correction method.

[0030] The following is described by taking specific embodiments as examples:

[0031] Embodiment 1: The TianQin project is an important part of the Chinese gravitational wave detection project. The TianQin project will launch three satellites, and the gravitational wave detection satellite will be affected by external heat flow of various frequencies in space during the execution of the task, which will cause temperature noise of the corresponding frequency. The satellite needs to achieve temperature noise control in the range of 0.1 mHz-0.1 Hz, and pure passive thermal control materials cannot suppress ultra-low frequency temperature noise. The present application proposes a low-frequency temperature noise active suppression method based on phase compensation and feedback correction, which adopts the method principle conceptual diagram as shown in Figure 1 , compensation heat flow calculation is performed through external heat flow identification frequency domain analysis.

[0032] Referring to Figure 2 , the structure diagram of the low-frequency temperature noise active suppression method based on phase compensation and feedback correction includes heat flux sensors 1 and 5, heating devices 2, and passive thermal control materials 3 and 4. The passive thermal control material can be multi-layered and variable in thickness. Referring to Figure 3 , when the input heat flow is transferred to the compensation interface 4, the heat flow has the same amplitude as the compensation heat flow and a phase difference of 180°. Referring to Figure 4 , low-frequency periodic heat flow heat-amplitude attenuation characteristics, the amplitude attenuation characteristics are related to the frequency. Referring to Figure 6, the low-frequency periodic heat flow heat transfer-phase delay characteristic, the phase delay time is related to the frequency. See Figure 7 , the temperature fluctuation of the monitoring point before and after the phase compensation. The heating device through the phase compensation compensates the heat flow transferred to the compensation interface, reduces the heat flow amplitude, reduces the heat flow fluctuation, and thus achieves the effect of reducing the temperature fluctuation. The front passive thermal control material 3 can reduce the heat flow amplitude, reduce the power requirement of the heating device, reduce the thermal compensation amount, and provide time delay for active control. See Figure 7 , the temperature noise can be reduced by 89.3% when the heat flow frequency is 0.001Hz, and the temperature noise can be reduced by 99.4% when the heat flow frequency is 0.02Hz.

[0033] Embodiment 2: The difference between embodiment 2 and embodiment 1 is that the feedback correction method is added on the basis of the phase compensation method, the heat flux sensor 5 collects the heat flow data of the controlled part before and after the compensation, and the parameter adjustment of the compensation heat flow is carried out according to the feedback correction method based on the collected heat flow data. See Figure 9 , when the input heat flow is 0.0001Hz, 0.0005Hz, 0.002Hz, and the amplitude is 40W / m 2 , after 4 times of feedback correction, the temperature noise suppression effect of the phase compensation method is greatly improved compared with that without feedback correction, and the temperature noise is 99.46%, 99.47%, and 99.68% of that without feedback correction.

[0034] Embodiment 3: The difference between embodiment 3 and embodiment 4 is that the frequency, amplitude and phase of the input heat flow are randomly generated. See Figure 10 , when the input heat flow frequency is 0.0003Hz, 0.0007Hz, and 0.002Hz, the initial phase compensation can reduce the corresponding frequency temperature noise by 77.76%, 90.17%, and 95.95% respectively. After 4 times of feedback correction, the temperature noise can be further reduced to 98.68%, 99.70%, and 99.68% of that without phase compensation.

[0035] Therefore, the low-frequency temperature noise active suppression method based on phase compensation and feedback correction provided by the present application mainly controls the active external heat flow phase compensation, collects the external input heat flow in real time, carries out spectrum analysis and heat flow restoration, calculates the compensation heat flow combined with the low-frequency periodic heat flow heat transfer characteristic, and converts it into a voltage signal to control the output power of the thermal compensation device. The input heat flow is phase compensated, so as to effectively suppress the temperature noise caused by the low-frequency heat flow noise. On the basis of the phase compensation method, the compensation heat flow feedback correction method is added to improve the compensation heat flow accuracy, enhance the temperature noise suppression effect, improve the temperature stability and measurement accuracy of the precision instrument, and meet the higher requirements of modern science and technology on the performance of the precision instrument.

[0036] The above description is only the preferred embodiment of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can make equivalent replacements or changes according to the technical solution and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.

Claims

1. A method for actively suppressing low-frequency temperature noise based on phase compensation and feedback correction, characterized in that, This is achieved using an active noise suppression structure for suppressing temperature noise over a wide frequency band, and includes the following steps: S1. Real-time acquisition of input heat flow generated by external heat sources; S2. Perform spectral analysis on the input heat flow, analyze the noise power spectral density or amplitude spectral density of the input heat flow, select the frequency that needs to be compensated, and restore the input heat flow by inverse Fourier transform in combination with the frequency domain characteristics to obtain the heat flow of the corresponding frequency that needs to be compensated in the input heat flow. S3. Based on the heat flow to be restored as needed and the heat transfer-phase delay-amplitude attenuation characteristics of low-frequency periodic heat flow heat conduction, calculate the corresponding compensation heat flow. S4. The compensation heat flow is matched with the corresponding heat flow and then input to the input heat flow for feedback correction. After inputting the phase compensation heat flow, temperature noise suppression is completed.

2. The method for active suppression of low-frequency temperature noise based on phase compensation and feedback correction according to claim 1, characterized in that, Step S3 includes the following steps: The compensation heat flux is calculated based on the aforementioned heat flux. Reduced input heat flux Q in : The noise amplitude spectral density (ASD) of the input heat flux is obtained through spectral analysis. Q Select the heat flux that needs compensation, and calculate the amplitude attenuation δ(f) and phase delay τ(f) characteristics of the heat flow at that frequency based on the selected frequency f. Calculate the heat flux Q′ when the heat flux is transferred to the compensation interface. in : Based on the required reconstructed heat flow and the heat transfer-phase delay-amplitude attenuation characteristics of low-frequency cyclic heat flow conduction, the attenuated amplitude and delayed phase of the heat flow reaching the compensation interface are calculated. The phase of the compensation heat flow differs from the phase of the input heat flow reaching the compensation interface by approximately 180° (π). The compensation heat flow obtained based on this criterion is: Considering the bidirectional propagation of heat flow, the amplitude of the final compensated heat flow is approximately twice the amplitude of the attenuated heat flow: B c，i =2B i ; The final compensating heat flow is obtained: Where A′>B c，i The sum; The voltage corresponding to the compensating heat flow is output by controlling the voltage signal, and the heater outputs the compensating heat flow.

3. The method for active suppression of low-frequency temperature noise based on phase compensation and feedback correction according to claim 2, characterized in that, Step S4 includes: Heat flux data Q of the controlled part is collected by a heat flux sensor at the controlled part after phase compensation. M1 ; using the heat flux data Q before and after compensation at the controlled part M Q M1 Based on this, the phase and amplitude of the compensating heat flux are adjusted using a feedback correction method. The feedback correction method is as follows: After phase compensation, the heat flux of the controlled part is affected by both the compensated heat flux and the input heat flux. The portion affected by the compensated heat flux is denoted as Q. M2 Its calculation formula is: Q M2 =Q M -Q M1 ; Comparison Q M1 With Q M2 The amplitude and phase are adjusted, and the amplitude and phase are increased or decreased according to the difference between the amplitude and phase. Based on the adjusted amplitude and phase, the voltage signal is controlled to output the voltage of the corresponding adjusted compensation heat flow, and the heater outputs the adjusted compensation heat flow.

4. The method for active suppression of low-frequency temperature noise based on phase compensation and feedback correction according to claim 1, characterized in that, The active noise suppression structure includes a passive thermal control material, multiple heat flux sensors, multiple heat flux compensation heating devices, and a controller; the multiple heat flux sensors and the multiple heat flux compensation heating devices are one-to-one, and each heat flux sensor is connected to the controller and the corresponding heat flux compensation heating device.

5. The method for active suppression of low-frequency temperature noise based on phase compensation and feedback correction according to claim 4, characterized in that, The heat flux sensor is disposed on the side of the passive thermal control material facing the heat source; the heat flux compensation heating device is disposed in the passive thermal control material and close to the front half of the heat source.

6. The method for active suppression of low-frequency temperature noise based on phase compensation and feedback correction according to claim 2, characterized in that, The feedback correction method adjusts the phase and amplitude of the compensated heat flux based on phase compensation. When performing feedback correction adjustment of the compensated heat flux, the data before and after compensation must start at the same time, and the phase of the input heat flux at that time after compensation must be the same as before compensation. The length of the time period taken is the length of the corresponding frequency period.

7. The method for active suppression of low-frequency temperature noise based on phase compensation and feedback correction according to claim 6, characterized in that, The rules for increasing or decreasing phase and amplitude are as follows: First adjust the phase, then adjust the amplitude; adjust only one parameter per feedback cycle. If Q M2 The phase is less than Q M1 If the phase is Q, then Q M2 The phase needs to be increased by an amount of Q. M2 With Q M1 absolute value of phase difference When Q M2 Minimum value and Q M1 When the absolute value of the position difference of the maximum value is less than 1 / 500 of the period, the phase adjustment can be considered complete. Amplitude adjustment is then performed. If Q... M2 The absolute value of the extreme value is greater than Q. M1 If the absolute value of the extreme value is reached, then the amplitude needs to be reduced; if Q M2 The absolute value of the extreme value is less than Q. M1 If the absolute value of the extreme value is reached, then the amplitude needs to be increased. The increase or decrease amplitude is Q. M2 The extreme values ​​and absolute values ​​of Q M1 The difference between the extreme absolute values ​​ΔB M The absolute value of |ΔB M | 8. The method for active suppression of low-frequency temperature noise based on phase compensation and feedback correction according to claim 1, characterized in that, The wideband refers to the frequency range of less than 0.1 Hz.

9. The method for active suppression of low-frequency temperature noise based on phase compensation and feedback correction according to claim 1, characterized in that, For multi-frequency composite heat flux, Q M Q M1 Q M2 Frequency domain analysis is required through Fourier transform decomposition, and component single-frequency heat flux is restored through inverse Fourier transform. Then, the phase and amplitude of the compensated heat flux are adjusted through feedback correction method.

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