Networked low-power direct-current power supply bus observer in special environment

Abstract

The invention relates to a networked low-power direct-current power supply bus observer in a special environment, which comprises a voltage preprocessing module, a high-frequency ripple acquisition module and a networked module, and is characterized in that the networked module is connected with the voltage preprocessing module and the high-frequency ripple acquisition module; the voltage preprocessing module comprises a subtractor, an adjustable reference voltage generation circuit and a filtering module, the first input end of the subtractor is connected to the output end of the DC / DC converter, the second input end of the subtractor is connected to the output end of the adjustable reference voltage generation circuit, the output end of the subtractor is connected to the filtering module, and the filtering module is connected to the high-frequency ripple acquisition module; the adjustable reference voltage generating circuit generates a fixed reduced voltage, the subtracter subtracts the reduced voltage from the voltage output by the DC / DC converter, and then the filtering module filters the DC component of the voltage output by the DC / DC converter and noise generated by the adjustable reference voltage generating circuit. Compared with the prior art, the method has the advantages of high reliability and the like.

Description

Technical Field

[0001] The invention relates to a direct current power supply bus observer, in particular to a networked low-power direct current power supply bus observer under special conditions. Background Art

[0002] Systems working in special environments, such as seabed observation networks and spacecraft, require the power supply system to be highly reliable and work stably for a long life.

[0003] Therefore, relevant data collection is required to understand the working status of each system. In the prior art, collecting ripple voltage is an important means. Usually, ripple voltage is collected through tools such as oscilloscopes, but this method is costly. Secondly, some special environments, such as seabed observation networks, spacecraft, etc., are often difficult to access. Therefore, the traditional oscilloscope detection method is less feasible.

[0004] In this regard, some existing technologies choose to use a voltage acquisition unit to collect voltage. For example, Chinese patent CN117175913A discloses an adaptive voltage preprocessing device and method for DC / DC converter ripple acquisition. The device mainly includes: an ADC acquisition circuit, which is used to collect and store DC voltage values ​​to provide data for the adaptive algorithm; a DAC and reference voltage closed-loop adaptive adjustment circuit, in which the DAC outputs reference voltages corresponding to different DC / DC converter output voltages, and collects the reference voltage through the ADC for closed-loop feedback adjustment; a networking function and a supporting server. The device is also equipped with a network function, and a supporting server is built to realize networked remote transmission of DC voltage data.

[0005] However, the above device uses ADC acquisition for closed-loop control. On the one hand, the stability of cheap ADC is low. It is difficult to maintain high stability in complex environments, such as some spacecraft with strong electromagnetic interference and temperature changes. On the other hand, the noise generated by the subtractor will be carried to the next stage, which also increases the requirements for the processing of the next stage. Summary of the invention

[0006] The purpose of the present invention is to provide a networked low-power DC power supply bus observer under special environments. By adopting an adjustable reference voltage generation circuit to replace ADC and adaptive algorithm, the reliability can be greatly improved. Stable and reliable operation can be achieved in high radiation conditions and high temperature difference conditions such as in the aerospace field, thereby improving reliability while reducing costs.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] A networked low-power DC power supply bus observer under special environment includes a voltage preprocessing module, a high-frequency ripple acquisition module and a networking module, wherein the networking module is connected to the voltage preprocessing module and the high-frequency ripple acquisition module respectively.

[0009] The voltage preprocessing module includes a subtractor, an adjustable reference voltage generating circuit and a filter module, wherein the first input end of the subtractor is connected to the output end of the DC converter, the second input end is connected to the output end of the adjustable reference voltage generating circuit, the output end is connected to the filter module, and the filter module is connected to the high-frequency ripple acquisition module;

[0010] The adjustable reference voltage generating circuit generates a fixed subtracted voltage, and the subtractor subtracts the subtracted voltage from the DC / DC converter output voltage, and then filters out the DC component in the voltage output by the DC converter and the noise generated by the adjustable reference voltage generating circuit through the filtering module.

[0011] The adjustable reference voltage generating circuit comprises a voltage regulator, an input filtering unit, a first sampling unit and a second sampling unit, wherein the input pin of the voltage regulator is connected to the output end of the DC converter via the input filtering unit, the first sampling unit is respectively connected to the input pin and the first sampling pin of the voltage regulator, and the second sampling unit is respectively connected to the output pin and the second sampling pin of the voltage regulator;

[0012] The first sampling unit collects the voltage at the input end, and the second sampling unit collects the voltage at the output end, and feedback control is performed to adjust the voltage difference between the output and input of the voltage regulator to be constant.

[0013] The first sampling unit includes a third resistor and a fourth resistor, one end of the third resistor is connected to the input pin of the voltage regulator, and the other end is connected to the first sampling pin of the voltage regulator and one end of the fourth resistor, the other end of the fourth resistor is grounded, and the third resistor and the fourth resistor are both fixed value resistors.

[0014] The second sampling unit includes a first resistor and a second resistor, wherein a first end of the first resistor is connected to an output pin of the voltage regulator, a second end is connected to a second sampling pin of the voltage regulator and one end of the second resistor, and the other end of the second resistor is grounded, and both the first resistor and the second resistor are fixed value resistors.

[0015] The input filter unit includes a first filter capacitor.

[0016] The adjustable reference voltage generating circuit further includes an output filtering unit.

[0017] The output filter unit includes a second filter capacitor and a first filter inductor, one end of the first filter inductor is connected to the output pin of the voltage regulator, and the other end is connected to the first end of the first resistor and one end of the second filter capacitor, and the second input end of the subtractor, and the other end of the second filter capacitor is grounded.

[0018] The subtractor comprises an operational amplifier, a first input terminal of the subtractor is a non-inverting input terminal of the operational amplifier, and a second input terminal of the subtractor is an inverting input terminal of the operational amplifier.

[0019] The filtering module includes a DC bias filtering unit and a low-frequency signal filtering unit.

[0020] The high-frequency ripple acquisition module includes a signal conditioning circuit, a high-speed A / D converter, an FPGA and a processor which are connected in sequence.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. By using an adjustable reference voltage generation circuit to replace ADC and adaptive algorithm, the reliability can be greatly improved. Stable and reliable operation can be achieved in high radiation conditions and high temperature difference conditions such as in the aerospace field, thereby improving reliability while reducing costs.

[0023] 2. Voltage clamping is achieved through a voltage regulator, and voltage acquisition is achieved based on a hardware circuit, thereby further improving reliability.

[0024] 3. Both the first sampling unit and the second sampling unit are implemented in the form of a resistive voltage divider circuit, thereby reducing the voltage input of the first sampling pin and the second sampling pin of the voltage regulator. On the one hand, it can reduce energy consumption, and on the other hand, it can also reduce interference to the main circuit by reducing the voltage level, thereby improving the control accuracy of the output voltage of the voltage regulator.

[0025] 4. The output filter unit adopts LC series filtering, and the second sampling unit is connected after the first filtering inductor, which can reduce the interference of noise generated by the error caused by following on the sampling result of the second sampling unit and improve the accuracy.

[0026] 5. The filtering module includes a DC bias filtering unit and a low-frequency signal filtering unit. On the one hand, it can filter out the original DC bias, and on the other hand, it can also filter out the low-frequency noise generated by the voltage regulator itself, thereby improving the accuracy of ripple sampling. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the module composition of the voltage preprocessing module;

[0028] Figure 2This is a schematic diagram of the module composition of the high-frequency ripple acquisition module;

[0029] Figure 3 It is a structural schematic diagram of the present invention;

[0030] Figure 4 It is a circuit principle diagram of the voltage preprocessing module;

[0031] Among them: 1. DC / DC converter, 2. voltage preprocessing module, 3. high-frequency ripple acquisition module, 4. networking module, 21. subtractor, 22. adjustable reference voltage generation circuit, 23. filtering module, 31. signal conditioning circuit, 32. high-speed A / D converter, 33. FPGA, 41. processor, 42. A / D converter. DETAILED DESCRIPTION

[0032] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0033] A networked low-power DC power supply bus observer under special conditions, such as Figure 3 As shown, it includes a voltage preprocessing module 2, a high-frequency ripple acquisition module 3 and a networking module 4, and the networking module 4 is connected to the voltage preprocessing module 2 and the high-frequency ripple acquisition module 3 respectively.

[0034] A voltage preprocessing module 2 is designed to process the input voltage within a certain range to meet the data acquisition requirements without affecting the normal operation of the power supply bus; a data acquisition scheme is designed for the preprocessed voltage data; in response to the long-distance monitoring requirements of the power supply system under special environments, the networked communication function of the observer is developed, and a cloud server is built; a low-power SuperBuck converter 1 is used to simulate a DC power supply bus DC / DC converter operating in a special environment to demonstrate the practical application of this application.

[0035] Under special circumstances, the DC output voltage of the DC / DC converter of the DC power supply bus has a large variation range and cannot meet the acquisition requirements of the ADC chip. The peak-to-peak value of the ripple voltage in the output voltage is generally within 100mV, and the frequency is generally 100kHz or above, which is a periodic atypical waveform. Due to the characteristics of high frequency, low amplitude, and non-sinusoidal, it is very difficult to collect and transmit ripple voltage data at high speed and high precision through networking.

[0036] like Figure 1As shown, the voltage preprocessing module 2 includes a subtractor 21, an adjustable reference voltage generating circuit 22 and a filter module 23, the first input end of the subtractor 21 is connected to the output end of the DC converter, the second input end is connected to the output end of the adjustable reference voltage generating circuit 22, the output end is connected to the filter module 23, and the filter module 23 is connected to the high-frequency ripple acquisition module 3;

[0037] Since the output voltage value of the DC / DC converter of the DC power supply bus is higher than the withstand voltage value of the active device under special circumstances, directly sending it to the active device for processing often causes damage to the device. Subtractor 21, as one of the typical applications of the operational amplifier U2, can realize the subtraction operation of two different DC voltage values. At the same time, the ideal input impedance of the operational amplifier U2 is infinite. After the power supply bus is connected to the subtractor 21 circuit through the voltage follower, it is equivalent to connecting a resistor with infinite resistance in parallel, which will not affect the normal working state of the power supply bus.

[0038] In order to provide an accurate and stable DC reference voltage, the present application designs an adjustable reference voltage generation circuit 22, which can output a fixed DC voltage value. The output voltage of the power supply bus DC / DC converter is connected to the non-inverting terminal of the operational amplifier U2, and the reference voltage is connected to the inverting terminal of the operational amplifier U2, so as to subtract the power supply bus output voltage from the reference voltage, thereby achieving the purpose of attenuating the DC voltage of the power supply bus DC / DC converter.

[0039] The output voltage of the subtractor 21 circuit includes: DC voltage, converter ripple voltage and low-frequency ripple generated by the subtractor 21 circuit. At this time, a high-pass filter is required to filter out the DC voltage and low-frequency ripple. Since the ripple frequency (100KHz and above) in the DC converter 1 is very high compared to the DC and low-frequency ripple frequencies, the high-frequency ripple can be separated from the output voltage of the subtractor 21 by reasonably designing the high-pass filter cutoff frequency.

[0040] The adjustable reference voltage generating circuit 22 generates a fixed subtracted voltage. The subtractor 21 subtracts the subtracted voltage from the voltage output by the DC converter, and then filters out the DC component in the voltage output by the DC converter and the noise generated by the adjustable reference voltage generating circuit 22 through the filtering module 23.

[0041] By adopting the adjustable reference voltage generating circuit 22 to replace the ADC and the adaptive algorithm, the reliability can be greatly improved, and stable and reliable operation can be achieved in high radiation conditions and high temperature difference conditions such as in the aerospace field, thereby improving reliability while reducing costs.

[0042] like Figure 4As shown, the adjustable reference voltage generating circuit 22 includes a voltage regulator U1, an input filtering unit, a first sampling unit and a second sampling unit. The input pin Vin of the voltage regulator U1 is connected to the output end of the DC converter 1 via the input filtering unit. The first sampling unit is respectively connected to the input pin Vin and the first sampling pin Iset of the voltage regulator U1. The second sampling unit is respectively connected to the output pin SW and the second sampling pin FB of the voltage regulator U1.

[0043] The first sampling unit collects the voltage at the input end, and the second sampling unit collects the voltage at the output end, and feedback control is performed to adjust the voltage difference between the output and input of the voltage regulator U1 to be constant. The voltage is clamped by the voltage regulator U1, and the voltage is collected based on the hardware circuit, thereby further improving reliability.

[0044] The first sampling unit includes a third resistor R3 and a fourth resistor R4, one end of the third resistor R3 is connected to the input pin Vin of the voltage regulator U1, and the other end is connected to the first sampling pin Iset of the voltage regulator U1 and one end of the fourth resistor R4, the other end of the fourth resistor R4 is grounded, and the third resistor R3 and the fourth resistor R4 are both fixed value resistors.

[0045] The second sampling unit includes a first resistor R1 and a second resistor R2. The first end of the first resistor R1 is connected to the output pin SW of the voltage regulator U1, the second end is connected to the second sampling pin FB of the voltage regulator U1 and one end of the second resistor R2, and the other end of the second resistor R2 is grounded. The first resistor R1 and the second resistor R2 are both fixed value resistors.

[0046] The first sampling unit and the second sampling unit are both implemented in the form of a resistive voltage divider circuit, so that the voltage input of the first sampling pin Iset and the second sampling pin FB of the voltage regulator U1 can be reduced. On the one hand, energy consumption can be reduced, and on the other hand, interference to the main circuit can be reduced by reducing the voltage level, thereby improving the control accuracy of the output voltage of the voltage regulator U1.

[0047] The input filter unit includes a first filter capacitor Cin.

[0048] The adjustable reference voltage generating circuit 22 further includes an output filtering unit.

[0049] The output filter unit includes a second filter capacitor Cout and a first filter inductor L1, one end of the first filter inductor L1 is connected to the output pin SW of the voltage regulator U1, and the other end is connected to the first end of the first resistor R1 and one end of the second filter capacitor Cout, and the second input end of the subtractor 21, and the other end of the second filter capacitor Cout is grounded.

[0050] The output filter unit adopts LC series filtering, and the second sampling unit is connected after the first filtering inductor L1, which can reduce the interference of noise generated by the error caused by following on the sampling result of the second sampling unit and improve the accuracy.

[0051] The subtractor 21 includes an operational amplifier U2 , a first input terminal of the subtractor 21 is a non-inverting input terminal of the operational amplifier U2 , and a second input terminal of the subtractor 21 is an inverting input terminal of the operational amplifier U2 .

[0052] The filter module 23 includes a DC bias filter unit and a low-frequency signal filter unit. By including the DC bias filter unit and the low-frequency signal filter unit in the filter module 23, the original DC bias can be filtered out on the one hand, and the low-frequency noise generated by the voltage regulator U1 itself can be filtered out on the other hand, thereby improving the accuracy of ripple sampling.

[0053] like Figure 2 As shown, the high-frequency ripple acquisition module 3 includes a signal conditioning circuit 31, a high-speed A / D converter 32, an FPGA and a processor 41 connected in sequence. According to the Nyquist sampling theorem, the sampling frequency is at least twice the ripple frequency. In order to make the collected ripple voltage continuous and accurate, the sampling frequency needs to reach several times the ripple frequency. In view of the characteristics of the ripple voltage at the output end of the DC power supply bus DC / DC converter under special environments, the present application uses a high-speed A / D converter 32 as the core sampling device to design a ripple voltage acquisition solution that combines a high-speed A / D converter 32, an FPGA (Field Programmable Gate Array) and a processor 41.

[0054] Among them, FPGA has high-speed parallel computing capabilities and can be used as a driver for the high-speed A / D converter 32 to provide it with a high clock frequency. At the same time, FPGA also serves as a data transfer station to collect and cache data and transmit the data to the processor 41 through serial communication; the processor 41 not only needs to process ripple data, but also is the core component for subsequent data visualization and networking; in addition, in order to ensure the accuracy of data collected by the high-speed A / D converter 32, a voltage conditioning circuit needs to be designed to keep the ripple voltage within the collection range of the A / D converter.

[0055] Since the amplitude of the ripple voltage can be directly ignored compared to the DC output voltage, and the DC voltage output by the power supply bus DC / DC converter is attenuated after the subtractor 21 in the voltage preprocessing module 2, its voltage value is within the voltage acquisition range of the high-precision A / D converter. Therefore, for the DC voltage, the output voltage of the subtractor 21 in the aforementioned voltage preprocessing module 2 can be directly used as the acquisition value, and the high-precision A / D converter can be used for acquisition, and then the system processor 41 can perform software compensation to restore the DC voltage value. The specific acquisition points are as follows: Figure 1 shown.

[0056] The collected DC voltage data and ripple data are visualized locally, and the ripple data is processed by wavelet decomposition and noise reduction. At the same time, the data is transmitted to the cloud server based on FTP (File Transfer Protocol) for subsequent voltage data analysis and use.

[0057] like Figure 3 As shown, after the ripple data is processed by the wavelet decomposition noise reduction algorithm, the processor 41 outputs the DC voltage data and the noise-reduced ripple data to the display screen through the HDMI video output interface for visualization. With the help of the built-in network card or network interface of the processor 41, in any area covered by the network signal, by joining a wireless local area network or connecting a network cable, satellite communication, etc., the processor 41 can be connected to the network service, thereby enabling the data of the observer to be transmitted through the network.

[0058] After the processor 41 obtains the network service, the observer implements data file transmission based on the file transfer protocol, and can upload and save the collected data to the built cloud server for other authorized users or devices to access and download. The observer supports both on-site control and remote control.

[0059] According to the networked low-power DC power supply bus observer designed in this application under special environment, the low-power SuperBuck experimental board is used to simulate the low-power DC / DC converter running in special environment to verify the feasibility of developing the observer. The modules and their functions are shown in Table 1, and the experimental equipment and its functions are shown in Table 2:

[0060] Table 1 Modules and their functions

[0061]

[0062]

[0063] The SuperBuck low-power DC converter 1 used in this experiment is powered by the DC power supply in Table 2, and its output voltage is 24V; the load resistance value of the SuperBuck is set to 12Ω using a DC electronic load; the SuperBuck working power is 48W. During the experiment, a high-precision oscilloscope is used to measure the output voltage of each module of the observer and the ripple waveform of the DC converter 1 to verify whether the design of each module meets the requirements and compare it with the ripple collected by this observer. The following are the specific experimental steps:

[0064] Step 1: After the output voltage of SuperBuck DC converter 1 is connected to the observer, adjust the reference voltage generation circuit to output a 20V reference voltage. Use an oscilloscope to measure the output voltage and ripple of DC converter 1. The reference voltage generation circuit introduces a low-frequency ripple of about 35Hz, which needs to be filtered out by a high-pass filter.

[0065] Step 2: The output voltage of the DC converter 1 is subtracted from the reference voltage in the subtractor 21 circuit. The output voltage waveform of the subtractor 21 is collected by an oscilloscope, which includes a DC voltage of about 4V, a high-frequency ripple of the DC converter 1, a 35Hz low-frequency ripple introduced by the reference voltage generation circuit, and other clutter. The voltage value at this time meets the input voltage requirement of the high-pass filter and can be connected to the filter circuit. At the same time, the DC voltage is collected by ADS1115, and the data is transmitted to the processor 41 by IIC (Inter-Integrated Circuit, integrated circuit bus) communication. The processor 41 performs software compensation on it to restore the output DC voltage of the low-power DC / DC converter under special environment.

[0066] Step 3: The high-pass filter circuit filters out the DC voltage and low-frequency ripple. The output voltage ripple of the filter circuit measured by an oscilloscope is compared with the output ripple of the DC converter 1 collected in step 1. At this time, the voltage component only contains the high-frequency ripple in the output voltage of the DC converter 1.

[0067] Step 4: The high-frequency ripple data is collected by the high-speed A / D converter 32 driven by the FPGA, and the data is transmitted to the Raspberry Pi through the USB (Universal Serial Bus) serial port. The high-speed A / D converter 32AD9481 is an 8-bit analog-to-digital converter chip with a sampling rate of up to 250MSPS (Samples per Second), differential nonlinearity (DNL) and integral nonlinearity (INL) of ±0.35LSB and ±0.26LSB respectively. The sampling rate and accuracy meet the requirements. At the same time, the chip operating temperature is -40℃~+85℃, and it can operate normally in special environments.

[0068] The ripple data is processed by wavelet decomposition and denoising. After experimental testing, the wavelet base is selected as db6 wavelet, the number of decomposition layers is 8, and the threshold selection method is a fixed threshold. At this time, the ripple frequency is about 170kHz. The ripple waveform becomes smoother. The experiment proves the feasibility of the observer designed in this application for ripple collection and the effectiveness of the wavelet decomposition denoising algorithm.

[0069] Step 5: Since some data information will be lost after wavelet decomposition and noise reduction, after receiving the ripple data and DC voltage data, the Raspberry Pi directly transmits the data to the server through the FTP protocol without noise reduction processing to ensure the integrity of the collected data information.

[0070] The processor 41 can be a Raspberry Pi, and the onboard Micro-HDMI video output interface is connected to the touch screen. The device can be used without a mouse, keyboard or other peripherals through touch screen control. At the same time, a user interface is specially designed for the voltage acquisition function to improve the user experience. In addition, after obtaining the IP address of the Raspberry Pi and the management information of the relevant user, the observer can be remotely accessed and controlled through methods such as VNC (Virtual Network Computing). Further, based on the Raspberry Pi, the voltage acquisition module can be programmed and controlled through data transmission buses such as IIC and USB serial ports.

[0071] A cloud server was built as the key node of the system's networked communication, and it also realizes the storage and transfer of collected data. The parameters of the cloud server are shown in Table 3.

[0072] Table 3 Cloud server parameters

[0073]

[0074] The network communication function of the cloud server was tested using the ping command. Among the 40 64-byte data packets tested, the packet loss rate (Package Loss) was 0%, the sending and receiving order was correct, the response time was 6.439ms~12.609ms, and the average was 7.209ms, of which 1.021ms was the time consumed by the local hardware of the test device.

[0075] After the Raspberry Pi obtains the voltage data, it automatically sends the data to the server before performing visualization operations on it. After the data is sent, a pop-up window will appear on the observer's display screen to remind you that the server has received the data file named with the timestamp.

[0076] If the above functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program code.

Claims

1. A networked low-power DC power supply bus observer under special environment, comprising a voltage preprocessing module, a high-frequency ripple acquisition module and a networking module, wherein the networking module is respectively connected to the voltage preprocessing module and the high-frequency ripple acquisition module, and characterized in that: The voltage preprocessing module includes a subtractor, an adjustable reference voltage generating circuit and a filter module, wherein the first input end of the subtractor is connected to the output end of the DC converter, the second input end is connected to the output end of the adjustable reference voltage generating circuit, the output end is connected to the filter module, and the filter module is connected to the high-frequency ripple acquisition module; The adjustable reference voltage generating circuit generates a fixed subtracted voltage, and the subtractor subtracts the subtracted voltage from the DC / DC converter output voltage, and then filters out the DC component in the voltage output by the DC converter and the noise generated by the adjustable reference voltage generating circuit through the filtering module.

2. The networked low-power DC power supply bus observer under special environment according to claim 1, characterized in that: The adjustable reference voltage generating circuit comprises a voltage regulator, an input filtering unit, a first sampling unit and a second sampling unit, wherein the input pin of the voltage regulator is connected to the output end of the DC converter via the input filtering unit, the first sampling unit is respectively connected to the input pin and the first sampling pin of the voltage regulator, and the second sampling unit is respectively connected to the output pin and the second sampling pin of the voltage regulator; The first sampling unit collects the voltage at the input end, and the second sampling unit collects the voltage at the output end, and feedback control is performed to adjust the voltage difference between the output and input of the voltage regulator to be constant.

3. The networked low-power DC power supply bus observer under special environment according to claim 2, characterized in that: The first sampling unit includes a third resistor and a fourth resistor, one end of the third resistor is connected to the input pin of the voltage regulator, and the other end is connected to the first sampling pin of the voltage regulator and one end of the fourth resistor, the other end of the fourth resistor is grounded, and the third resistor and the fourth resistor are both fixed value resistors.

4. The networked low-power DC power supply bus observer under special environment according to claim 2, characterized in that: The second sampling unit includes a first resistor and a second resistor, wherein a first end of the first resistor is connected to an output pin of the voltage regulator, a second end is connected to a second sampling pin of the voltage regulator and one end of the second resistor, and the other end of the second resistor is grounded, and both the first resistor and the second resistor are fixed value resistors.

5. The networked low-power DC power supply bus observer under special environment according to claim 2, characterized in that: The input filter unit includes a first filter capacitor.

6. The networked low-power DC power supply bus observer under special environment according to claim 4, characterized in that: The adjustable reference voltage generating circuit further includes an output filtering unit.

7. The networked low-power DC power supply bus observer under special environment according to claim 6, characterized in that: The output filter unit includes a second filter capacitor and a first filter inductor, one end of the first filter inductor is connected to the output pin of the voltage regulator, and the other end is connected to the first end of the first resistor and one end of the second filter capacitor, and the second input end of the subtractor, and the other end of the second filter capacitor is grounded.

8. The networked low-power DC power supply bus observer under special environment according to claim 1, characterized in that: The subtractor comprises an operational amplifier, a first input terminal of the subtractor is a non-inverting input terminal of the operational amplifier, and a second input terminal of the subtractor is an inverting input terminal of the operational amplifier.

9. The networked low-power DC power supply bus observer under special environment according to claim 1, characterized in that: The filtering module includes a DC bias filtering unit and a low-frequency signal filtering unit.

10. The networked low-power DC power supply bus observer under special environment according to claim 1, characterized in that: The high-frequency ripple acquisition module includes a signal conditioning circuit, a high-speed A / D converter, an FPGA and a processor which are connected in sequence.

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