A high-precision wide-range current measurement device without switching and a signal processing method

Abstract

The present application belongs to the field of precision testing technology and instrument, the traditional non-contact current detection meets the basic demand of power monitoring to a certain extent, but when facing the complex and changeable measurement environment and the growing measurement precision requirement, the limitation gradually appears. The present application provides a high-precision large-range current measurement device and signal processing method without switching, through a high-sensitivity signal sampling unit, high-precision sampling of small current analog signals is realized, and two-stage passive filter circuit is added to the signal sampling unit to filter most of the clutter in the analog signal, the digital signal processing method is used in MCU to filter the digital current data with higher precision, the digital signal processing technology is applied to the field of current detection, through optimizing the detection circuit structure and signal processing process, high-precision and high-efficiency current measurement is realized.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of precision testing technology and instruments, and particularly relates to a high-precision large-range current measurement device without switching and a signal processing method. BACKGROUND

[0002] With the rapid development of the power industry and the deepening of the construction of smart grids, current detection technology, as an indispensable part of the power system, is becoming increasingly important, especially in modern industrial production, scientific research and power monitoring, etc. Higher requirements are put forward for the accuracy, real-time performance and safety of current detection. Traditional current detection devices, such as electromagnetic current sensors, although meet the needs of power monitoring to some extent, still have many shortcomings in practical application. Due to the limitations of structure and working principle, traditional electromagnetic current sensors have problems such as easy saturation of the core and difficulty in insulation. When the current is too large or there are harmonics, the saturation of the core will lead to a decrease in measurement accuracy, and the difficulty in insulation increases the safety hazards of the equipment. In order to overcome the shortcomings of traditional current detection devices, non-contact current detection equipment has emerged. Non-contact current detection equipment uses the principle of electromagnetic induction to indirectly measure the current value by detecting the magnetic field generated by the current. Compared with traditional electromagnetic current sensors, it has the advantages of non-contact measurement, wide dynamic range, electrical isolation and digital output. However, traditional non-contact current detection devices, although meet the basic needs of power monitoring to some extent, have limitations when faced with complex and variable measurement environments and increasing measurement accuracy requirements. Therefore, developing a new type of high-precision and high-efficiency non-contact current detection device combined with digital signal processing technology has become an important innovation direction in the current power industry.

[0003] Traditional non-contact current detection devices, such as sensors based on the Hall effect or the magnetoresistance effect, indirectly measure the current value by detecting the magnetic field generated by the current. However, these devices are often affected by various factors during measurement, such as environmental temperature and magnetic field interference, resulting in low measurement accuracy and poor stability. In addition, traditional devices have shortcomings in signal processing and data analysis, making it difficult to adapt to complex and variable measurement environments. The current market for non-contact current detection devices mainly includes products from companies such as Fluke in the United States and Oulide in China. The products on the current market all need to be switched according to the measurement range; the highest resolution of the Fluke product is 0.01A at 40A range, and the highest current resolution is 0.1A at 600A range; the highest measurement accuracy is 1.5% + 5 times the resolution; the products of Oulide and other domestic companies have lower measurement accuracy and stability at the same measurement resolution. SUMMARY

[0004] In order to overcome the limitations of traditional non-contact current detection equipment, the application provides a high-precision wide-range current measurement device without switching and a signal processing method, digital signal processing technology is combined with non-contact current detection, the digital signal processing technology is applied to the field of current detection, and through optimization of the structure of the detection circuit and the signal processing procedure, high-precision and high-efficiency current measurement is realized.

[0005] In order to achieve the above object, the technical scheme adopted by the application is as follows:

[0006] The high-precision wide-range current measurement device without switching comprises a main measurement unit, a signal acquisition unit, a signal amplification and filtering circuit unit, a high-precision AD conversion unit, an MCU for collecting high-precision data, and a digital signal processing unit, wherein:

[0007] The main measurement unit comprises two Hall current sensors, and the two Hall current sensors are respectively located at two ends of the opening and closing jaw head of the current clamp.

[0008] The signal input end of the signal acquisition unit is connected to the signal output end of the main measurement unit, and the Wheatstone bridge circuit is used to reduce the influence of lateral offset and longitudinal displacement on the detection precision.

[0009] The signal amplification and filtering circuit unit comprises a signal amplification part and a signal filtering part, the input end of the signal amplification part is connected to the output end of the signal acquisition unit, the output signal of the signal acquisition unit is transmitted to the signal filtering part after being amplified, and a smooth Hall potential signal is obtained.

[0010] The high-precision AD conversion unit converts the Hall potential analog signal output by the signal amplification and filtering circuit unit into a digital signal meeting the precision requirement through a programmable high-precision conversion unit, and the current resolution in the range of 200A reaches 0.001A.

[0011] The digital signal processing unit filters the high-precision data collected by the MCU to obtain a stable digital signal, and performs data calibration to obtain an accurate current signal.

[0012] Further, the application further comprises a wireless transmission and display unit, the wireless transmission unit sends the data of the accurate current signal obtained to an upper computer through the wireless transmission unit, and displays the data of the current signal in the upper computer.

[0013] Furthermore, the signal acquisition unit includes four resistors and two sliding rheostats. The output terminals OUT- and OUT+ of the Hall current sensor U4 are connected to resistors R17 and R18, respectively. The other ends of resistors R17 and R18 are connected to the fixed resistor terminals of the sliding rheostat RP3. The sliding terminal of the sliding rheostat RP3 serves as the first output terminal Uin1 of the Wheatstone bridge circuit and is connected to the positive input terminal of the operational amplifier U1.1.

[0014] The output terminals OUT- and OUT+ of the Hall current sensor U3 are connected to resistors R19 and R20, respectively. The other ends of resistors R19 and R20 are connected to the fixed terminals of the sliding rheostat RP4. The sliding terminal of the rheostat RP4 serves as the second output terminal Uin2 of the Wheatstone bridge circuit, which is connected to the positive input terminal of the operational amplifier U1.4. The two output terminals of the Wheatstone bridge circuit are filtered by capacitors C13 and C14, respectively.

[0015] A signal processing method for a non-switching high-precision large-range current measurement device, based on the aforementioned non-switching high-precision large-range current measurement device, involves the following steps within the MCU of the non-switching high-precision large-range current measurement device: estimating the current input value at the current moment based on the current input value at the previous moment, determining the accuracy of the current input value at the current moment, predicting and updating the output value, and filtering out noise interference with the true value.

[0016] Step 1. Set the circuit system parameters according to the non-switching high-precision large-range current measurement device: process noise Q, sensor measurement noise R, and initial estimated value X0;

[0017] Step 2. Based on the parameters set in Step 1, calculate the estimated value X for the current time using the following formula. i :

[0018] X i =X' i-1 +Q

[0019] Where X' i-1 This represents the estimated value updated at the previous time step, based on the estimated value X at the current time step. i Calculate the gain K of the circuit system g :

[0020]

[0021] Gain K g This indicates the proportion of the current estimate in the sum of the sensor measurement noise R and the current estimate, and is used as the weight of the current estimate and the measurement data;

[0022] Step 3. Calculate the output value out of the current time according to the gain obtained in step 2 i :

[0023] out i =out i-1 +K g (input i -out i-1 )

[0024] Wherein, input i is the input value of the current time, out i-1 is the output value of the last time, and out0 is 0;And update the estimated value X' i for the next time according to the following formula:

[0025] X' i =(1-K g )X i ;

[0026] Step 4. Repeat step 2 and step 3, estimate the dynamic response of the circuit system in a recursive manner to reduce the error between the estimated value and the true value, so that the noise can be effectively filtered out under the condition that the switching high-precision wide-range current measuring device exists interference.

[0027] In summary, the application has the following beneficial effects:

[0028] The application adopts open loop design, realizes 0-200A current measurement without switching range, the measurement resolution is 0.001A, the measurement accuracy can reach 1%±6mA, realizes the self-innovation of domestic high-precision measuring equipment. The Hall current sensor is used as the main measuring unit, which can accurately detect the magnetic field generated by the current, and through the optimized circuit structure and signal processing process, the noise interference is effectively filtered out, and the measurement accuracy is improved. At the same time, high-precision AD conversion unit and digital signal processing unit are used to further process the collected data, and the accuracy of the output current signal is ensured.

[0029] The application can offset the external magnetic field interference signal to each other through the symmetric Hall chip design, Wheatstone bridge circuit design and differential input amplification circuit design, so that only the magnetic field signal generated by the current change is collected and converted with high precision and then sent to MCU for processing, which improves the measurement accuracy and data stability of the application;The application combines hardware filter circuit and digital filter method to ensure the stability of the measurement data of the measuring device.

[0030] The application realizes high-precision sampling of tiny current analog signals through a high-sensitivity signal sampling unit, and adds two-stage passive filter circuits to the signal sampling unit to filter most of the clutter in the analog signals. The digital signal processing method is used in the MCU to perform higher-precision filtering on the digital current data, and the digital signal processing technology is applied to the current detection field. Through optimization of the detection circuit structure and the signal processing process, high-precision and high-efficiency current measurement is realized. The application can adapt to complex and variable measurement environments and the growing requirement for measurement accuracy, and provides an efficient and reliable current detection solution for the power industry. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 a detection method flowchart of the application;

[0032] Figure 2 a detection system block diagram of the application;

[0033] Figure 3 a signal acquisition part circuit diagram of the application;

[0034] Figure 4 a differential amplification circuit diagram;

[0035] Figure 5 a passive filter circuit diagram;

[0036] Figure 6 a comparison diagram of the data filtered by the signal processing method of the application (red curve in the diagram) and the original data without filtering (blue curve in the diagram). DETAILED DESCRIPTION

[0037] The application will be further described in detail below with reference to the accompanying drawings.

[0038] It should be noted that, for the sake of convenience, the direction in the following description is consistent with the direction of the drawings, but does not limit the structure of the application.

[0039] As shown in Figures 1-6 , the application discloses a high-precision wide-range current measurement device without switching, which comprises a main measurement unit, a signal acquisition unit, a signal amplification and filtering circuit unit, a high-precision AD conversion unit, an MCU for collecting high-precision data, and a digital signal processing unit. The main measurement unit comprises two Hall current sensors, and the two Hall current sensors are respectively located at the two ends of the opening and closing jaw heads of a current clamp. In this embodiment, the two Hall current sensors are respectively arranged at the air gaps of the opening and closing jaw heads, and the magnetic flux density generated by the leakage magnetic field at the gap is collected to generate a Hall potential, and the Hall potential generated by the magnetic flux density at the gap is detected by the two Hall current sensors.

[0040] The signal input end of the signal acquisition unit is connected with the signal output end of the main measurement unit, and the influence of the lateral offset and the longitudinal displacement on the detection precision is reduced through the Wheatstone bridge circuit, the lateral offset represents the offset distance of the detected wire harness in the axial direction of the wire harness itself relative to the center axis of the magnetic core gap, and the longitudinal displacement represents the displacement distance of the detected wire harness in the axial direction of the wire harness itself relative to the magnetic core gap, so as to avoid the influence of the potential change generated by the wire harness close to one end of the Hall current sensor and away from the other end of the Hall current sensor on the measurement value; the signal acquisition unit comprises four resistors and two slide rheostats, the output end OUT- and the output end OUT+ of the Hall current sensor U4 are respectively connected with the resistor R17 and the resistor R18, the other ends of the resistor R17 and the resistor R18 are respectively connected with the resistor fixed end of the slide rheostat RP3, and the sliding end of the slide rheostat RP3 is connected with the positive input end of the operational amplifier U1.1 as the first output end Uin1 of the Wheatstone bridge circuit; the output end OUT- and the output end OUT+ of the Hall current sensor U3 are respectively connected with the resistor R19 and the resistor R20, the other ends of the resistor R19 and the resistor R20 are respectively connected with the resistor fixed end of the slide rheostat RP4, and the sliding end of the slide rheostat RP4 is connected with the positive input end of the operational amplifier U1.4 as the second output end Uin2 of the Wheatstone bridge circuit; the two output ends of the Wheatstone bridge circuit are respectively filtered through the capacitor C13 and the capacitor C14. Through the bridge structure, the precision drift problem of the Hall current sensor due to temperature change is reduced, the potential changes of the two Hall current sensors are superimposed, the precision influence of the lateral offset and the longitudinal displacement of the wire harness at the gap of the clamp magnetic core is greatly reduced, and the collection sensitivity of the circuit is improved.

[0041] The signal amplification and filtering circuit unit comprises a signal amplification part and a signal filtering part, the input end of the signal amplification part is connected with the output end of the signal acquisition unit, the output signal of the signal acquisition unit is transmitted to the signal filtering part after being amplified, and a smooth Hall potential signal is obtained; the operational amplifier of the signal amplification and filtering circuit unit adopts a double-power supply mode, is suitable for the high-sensitivity signal generated by the above signal acquisition unit, the signal amplification part is divided into two stages, the first stage constitutes a unit gain follower, amplifies the differential voltage gain coefficient, and increases the common mode rejection ratio, and the second stage constitutes a differential amplification circuit, filters the common mode interference in the signal, and increases the sensitivity of the signal acquisition system. The signal filtering part is divided into two stages, the first stage filters the signal collected by the above signal amplification part, and a relatively smooth Hall potential signal is obtained, and the second stage amplifies and filters the above smooth Hall potential signal again, and a more smooth Hall potential signal is finally obtained.

[0042] The high-precision AD conversion unit converts the analog signal of the Hall potential signal output by the signal amplification and filtering circuit unit into a digital signal meeting the precision requirement through a programmable high-precision conversion unit, so that the current resolution reaches 0.001 A within the 200 A range, the current resolution of the present application is obviously superior to the existing products, and the conversion from the waveform signal of the analog quantity to the high-precision data of the digital quantity is completed; the high-precision data of the signal conversion is collected by the MCU; in the embodiment, the current resolution is 0.001 A, and the high-precision AD conversion unit adopts a programmable high-precision conversion unit to meet the precision requirement, and in the embodiment, the programmable high-precision conversion unit adopts ADS1263.

[0043] The digital signal processing unit filters the high-precision data converted by the MCU to obtain a stable digital signal, and performs data calibration to obtain an accurate current signal, since the slight fluctuation in the signal is also greatly magnified with the collection precision after the high-precision AD conversion, the digital signal processing unit filters the greatly magnified slight fluctuation to obtain a stable digital signal, and performs data calibration to obtain an accurate current signal.

[0044] The non-switching high-precision large-range current measurement device further comprises a wireless transmission and display unit, the wireless transmission unit sends the data of the accurate current signal obtained to the upper computer through the wireless transmission unit, and displays the data of the current signal in the upper computer, in the embodiment, the data is sent to the computer host or a device capable of realizing wireless communication such as a mobile phone through wireless WiFi, the data can be displayed on the present collection device, and the data can also be sent to the upper computer in a wireless mode, and the data is saved, displayed, and queried in the upper computer.

[0045] Figure 3is signal acquisition and Hall element power supply unit, wherein the right end circuit of Hall current sensor U3 and Hall current sensor U4 is a constant current source power supply circuit of Hall element, wherein voltage VDD+ is connected to the positive power supply end of operational amplifier U2, GND is connected to the negative power supply end of operational amplifier U2, a single power supply mode is formed, and the output range of operational amplifier U2 is within the reference voltage. Voltage VCC 1.2V is a reference voltage, wherein resistance R28 and resistance R16 are voltage dividing resistors, and the noise after voltage VCC 1.2V voltage division is filtered by filter capacitor C10. Since the output of operational amplifier U2 is affected by the input voltage, the output voltage of the output end of operational amplifier U2 can also be obtained. Capacitor C21 and capacitor C22 are also filter capacitors, and provide stable output voltage for operational amplifier U2. According to the concept of virtual short and virtual open, resistance R15 is a current limiting resistor, and the size of resistance R15 can limit the current value of the constant current source. The left end of Hall current sensor U3 and Hall current sensor U4 is connected to the signal output end of the main measurement unit through a Wheatstone bridge circuit. Due to the limitations of the manufacturing process of Hall current sensor, there is some error in the internal resistance and it is also easily affected by temperature. When the power supply part of the circuit is turned on, the output Hall electromotive force is not zero in the case of zero input signal, so a zero adjustment circuit needs to be designed to suppress temperature drift and zero drift, and realize zero input and zero output. Resistance R17, resistance R18, resistance R19, resistance R20, slide rheostat RP3 and slide rheostat RP4 constitute a Wheatstone bridge structure, two Hall elements are connected to the two input ends of the Wheatstone bridge respectively, this structure can offset the temperature drift of the Hall current sensor and superimpose the Hall potential change of the Hall element, improve the sensitivity of the circuit system, and the output ends of slide rheostat RP3 and slide rheostat RP4 can be adjusted to zero in the case of zero input to compensate for the internal defects of the Hall current sensor. Capacitor C13 and capacitor C14 are used for filtering and providing stable analog signal for subsequent circuit.

[0046] Figure 4The differential amplification circuit structure is connected with the output end of the Wheatstone bridge circuit, wherein the functions of the capacitors C17, C18, C19 and C20 are filtering, and stable voltage is provided for the operational amplifier of the differential amplification circuit and the active filter circuit; the power supply mode of the differential amplification circuit is a double power supply mode, which is commonly used in high-precision and high-performance circuits and is used for improving the stability and reliability of the circuit; the feedback end of the output of the operational amplifier U1.4 adopts a parallel structure of the resistor R21 and the capacitor C15, which can improve the stability of the operational amplifier; the connection mode of the operational amplifier U1.1 and the capacitor C16 and the resistor R22 is similar to the connection mode of the operational amplifier U1.4; the structure of the operational amplifier U1.1, the operational amplifier U1.4 and the resistor R23 constitutes a unit gain follower, the common mode signal passes through the input follower with a unit gain, the gain coefficient of the differential voltage is amplified, and the common mode rejection ratio of the circuit is increased; the outputs of the operational amplifier U1.1 and the operational amplifier U1.2 enter the input end of the operational amplifier U1.2 through the resistors R24 and R25 respectively, thereby forming a differential amplification circuit, filtering the common mode interference in the signal and increasing the sensitivity of the signal acquisition system; the signal Uout1 after filtering the common mode interference enters the two-stage passive filter circuit through the resistor R35, i.e., the first-stage passive filter circuit composed of the resistors R35 and R36 and the capacitors C7 and C8; after the filtered signal is amplified by the amplification circuit composed of the operational amplifier U1.3 by a multiple of R34 / R33, the signal is output to the high-precision AD conversion unit after the second-stage passive filter circuit composed of the resistors R31 and R32 and the capacitors C23 and C24. Figure 4 The differential amplification circuit of the application is connected with the passive filter circuit Figure 5 The power supply connection modes of the four operational amplifiers in the differential amplification circuit and the passive filter circuit are the same, and in actual use, a device in which the four operational amplifiers are integrated in one chip can be used.

[0047] The application further discloses a signal processing method of the switchless high-precision wide-range current measurement device, which is based on the switchless high-precision wide-range current measurement device, estimates the current input value at the current moment according to the current input value at the previous moment, judges the accuracy of the current input value at the current moment, makes a prediction and an update on the output value, and filters the interference of noise on the true value, and specifically includes the following steps.

[0048] Step 1. Parameters of the circuit system of the switchless high-precision wide-range current measurement device are set, including process noise Q, sensor measurement noise R and an initial estimated value X0; the three parameters can be adjusted according to the specific setting of the circuit system, and the sensor measurement noise R is an estimated value, i.e., the size of R is estimated by comparing the sensor measurement value with the set value of the standard current source.

[0049] Step 2. Based on the parameters set in Step 1, calculate the estimated value X for the current time using the following formula. i :

[0050] X i =X' i-1 +Q

[0051] Where X' i-1 This represents the estimated value updated at the previous time step, based on the estimated value X at the current time step. i Calculate the gain K of the circuit system g :

[0052]

[0053] Gain K g This indicates the proportion of the current estimate in the sum of the sensor measurement noise R and the current estimate, and is used as the weight of the current estimate and the measurement data;

[0054] Step 3. Calculate the output value out at the current time based on the gain obtained in Step 2. i :

[0055] out i =out i-1 +K g (input i -out i-1 )

[0056] Among them, input i The input value at the current moment, out i-1 The output value at the previous time step is given, and out0 is 0, meaning the output is 0 when there is no input signal; the estimated value X' at the current time step is updated according to the following formula. i For calculations at the next time step:

[0057] X' i = (1-K) g )X i ;

[0058] Step 4. Repeat steps 2 and 3 to estimate the dynamic response of the circuit system recursively, so as to reduce the error between the estimated value and the true value. The output value is corrected and continuously updated based on the difference between the measurement data obtained by the sensor and the input and output and the gain, so that the noise can be effectively filtered out under the condition of interference in the high-precision large-range current measurement device without switching.

[0059] like Figure 6As shown, the data filtered by the signal processing method of the application (red curve in the figure) can obviously eliminate the peak signal in the signal compared with the original data without filtering (blue curve in the figure), and the curve trend is obviously flat compared with the original data, realizing effective filtering of noise, and the application realizes accurate collection and efficient processing of a wide range of current signals, and improves the precision and stability of the non-switching high-precision wide-range current measuring device.

[0060] The above is only the preferred embodiment of the application, and the protection scope of the application is not limited to the above-mentioned embodiments. Any technical solution falling within the concept of the application shall fall within the protection scope of the application. It should be noted that for ordinary skilled persons in the art, some improvements and refinements without departing from the principles of the application shall also be considered as the protection scope of the application.

Claims

1. A signal processing method of a non-switching high-precision wide-range current measuring device, based on a non-switching high-precision wide-range current measuring device, characterized in that, The non-switching high-precision wide-range current measurement device comprises a main measurement unit, a signal acquisition unit, a signal amplification and filtering circuit unit, a high-precision AD conversion unit, an MCU for collecting high-precision data, and a digital signal processing unit, wherein: The main measurement unit comprises two Hall current sensors, which are respectively located at two ends of the opening and closing clamp head of the current clamp, and detect the Hall potential generated by the magnetic flux density at the gap through the two Hall current sensors; The signal input end of the signal acquisition unit is connected to the signal output end of the main measurement unit, and the influence of lateral offset and longitudinal displacement on the detection accuracy is reduced through the Wheatstone bridge circuit, wherein the lateral offset represents the offset distance of the detected wire harness in the axial direction of the wire harness itself relative to the center axis of the magnetic core gap, and the longitudinal displacement represents the displacement distance of the detected wire harness in the axial direction of the wire harness itself relative to the magnetic core gap; The signal amplification and filtering circuit unit comprises a signal amplification part and a signal filtering part, the input end of the signal amplification part is connected to the output end of the signal acquisition unit, and the output signal of the signal acquisition unit is transmitted to the signal filtering part after being amplified, to obtain a smooth Hall potential signal; The high-precision AD conversion unit converts the Hall potential analog signal output by the signal amplification and filtering circuit unit into a digital signal meeting the accuracy requirement through a programmable high-precision conversion unit, so that the current resolution within the 200A range reaches 0.001A; the high-precision data after signal conversion is collected by the MCU; The digital signal processing unit filters the high-precision data collected by the MCU to obtain a stable digital signal, and calibrates the data to obtain an accurate current signal; in the MCU of the non-switching high-precision wide-range current measurement device, the current input value at the current moment is estimated according to the current input value at the previous moment, and the accuracy of the current input value at the current moment is judged, and the output value is predicted and updated to filter out the noise interference on the true value, comprising the following steps: Step 1. Set the parameters of the circuit system of the non-switching high-precision wide-range current measurement device: process noise Q, sensor measurement noise R, and initial estimated value X0; Step 2. Calculate the current time estimate X according to the parameters set in Step 1, according to the following formula i : X i = X’ i-1 +Q wherein X i-1 represents the updated estimate at the previous time, and X i calculates the gain K g of the circuit system Gain K g represents the current estimate of the proportion of the sensor measurement noise R in the sum of the current estimate, as a weight of the current estimate and the measurement data; Step 3. Calculate the output value out at the current time instant from the gain obtained in step 2 i : out i = out i-1 +K g ( input i - out i-1 ) wherein, input i is the input value at the current time, out i-1 is the output value at the previous time, and out0 is 0; and the estimated value X' at the current time is updated according to the following formula: i for the calculation at the next time. X' i = (1 - K g ) X i ; Step 4. Repeat steps 2 and 3 to estimate the dynamic response of the circuit system in a recursive manner to reduce the error between the estimated value and the true value, so that the non-switching high-precision wide-range current measurement device can effectively filter out noise under the condition of interference.

2. The signal processing method of the high-accuracy wide-range current measuring device without switching according to claim 1, characterized by, It also comprises a wireless transmission and display unit, the wireless transmission unit sends the data of the accurate current signal obtained to the host computer through the wireless transmission unit, and displays the data of the current signal in the host computer.

3. The signal processing method of the high-accuracy wide-range current measuring device without switching according to claim 1, characterized by, The signal acquisition unit comprises four resistors and two slide rheostats, the output end OUT- and the output end OUT+ of the Hall current sensor U4 are respectively connected to the resistor R17 and the resistor R18, the other ends of the resistor R17 and the resistor R18 are respectively connected to the resistor fixed end of the slide rheostat RP3, and the slide end of the slide rheostat RP3 is connected to the positive input end of the operational amplifier U1.1 as the first output end Uin1 of the Wheatstone bridge circuit; The output end OUT- and the output end OUT+ of the Hall current sensor U3 are connected with the resistor R19 and the resistor R20 respectively, the other ends of the resistor R19 and the resistor R20 are connected with the resistance fixed end of the slide rheostat RP4, the slide end of the slide rheostat RP4 is connected with the positive input end of the operational amplifier U1.4 as the second output end Uin2 of the Wheatstone bridge circuit; the two output ends of the Wheatstone bridge circuit are filtered through the capacitor C13 and the capacitor C14 respectively.

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