Composite current detection sensor

Abstract

The invention discloses a composite current detection sensor, and belongs to the technical field of current detection and protection. A composite current detection sensor comprises a diverter, a zero sequence current coil, an electric leakage detection module, a current measurement module, a simulation electric leakage module and a thermocouple, and the diverter, the zero sequence current coil, the simulation electric leakage module, the electric leakage detection module and the current measurement module adopt a longitudinal layered layout. And an integrated high-efficiency diverter and a signal processing technology are arranged, so that accurate detection of alternating current and direct current is realized. The problems that the size of an existing sensor is increased, and the sensor can only measure alternating current but does not have a direct current measurement function are solved. According to the invention, the occupied space of the sensor can be reduced, installation and deployment can be completed in a small space, and simultaneous accurate detection of alternating current and direct current can be realized.

Description

Technical Field

[0001] The invention relates to the technical field of current detection and protection, in particular to a composite current detection sensor. Background Art

[0002] In modern industrial facilities and power systems, current detection sensors are key components to ensure safe operation of electrical equipment and prevent failures. Traditional current detection technology mainly relies on independent residual current sensors and current sensors to achieve leakage protection and current measurement and overcurrent protection functions respectively. However, the existing technical solutions have obvious limitations, which are as follows: Traditional sensors are large in size and occupy a large space. Usually, two independent devices are required to measure the residual current and rated current respectively. This results in the overall size of the sensor being large and difficult to adapt to application scenarios with strict restrictions on installation space, especially in compact equipment or high-density wiring environments. Large sensors not only increase the difficulty of installation, but may also affect the layout and performance of other components.

[0003] Most traditional sensors can only detect AC or DC, but not both. Since AC and DC power sources often coexist in industrial applications, there is a lack of sensors that can effectively process mixed AC and DC signals. This has become a major challenge in practical applications, especially in the field of new energy (such as solar power generation systems) and electric vehicle charging facilities. It is particularly important to accurately monitor AC and DC currents simultaneously. Summary of the invention

[0004] The object of the present invention is to provide a composite current detection sensor, which arranges a shunt, a zero-sequence current coil, a simulated leakage module, a leakage detection module and a current measurement module in a vertical layered layout, reduces the plane occupied space by vertical stacking, and realizes accurate detection of alternating current and direct current by integrating efficient shunts and signal processing technology. It can not only complete installation and deployment in a smaller space, but also realize simultaneous accurate detection of alternating current and direct current, so as to meet the diverse needs in modern complex electrical environments and solve the problems raised in the above-mentioned background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions: A composite current detection sensor, comprising the following components: A shunt, used to obtain a current flowing through the shunt by means of a voltage across both ends, and to form a loop with the conductor, wherein the loop passes through a zero-sequence current coil; Zero-sequence current coil, used to detect residual current; A leakage detection module, connected to the zero-sequence current coil, for obtaining a residual current signal of alternating current or direct current through the zero-sequence current coil, analyzing the residual current and outputting a leakage warning signal; A current measurement module is connected to both ends of the shunt through a wire, and is used to collect and amplify the voltage signals at both ends of the shunt, sample DC signals through a low-speed high-precision ADC and capture AC signals through a high-speed ADC, and calculate the current value of AC or DC according to the resistance value of the shunt and temperature compensation data; The simulation leakage module is used to detect whether the zero-sequence current coil and the leakage detection module are working normally; Thermocouples are used to monitor the temperature of the shunt and provide temperature compensation signals to the current measurement module. Based on the temperature data, compensation algorithms are used to adjust the measurement results to offset the errors caused by temperature changes. The shunt, zero-sequence current coil, simulated leakage module, leakage detection module and current measurement module are arranged in a vertical layered manner; The outer shell surface of the sensor is provided with a heat dissipation coating, and the spraying thickness of the heat dissipation coating is set based on the temperature rise parameters and the thermal conductivity properties of the material when the sensor is running.

[0006] Preferably, the longitudinal layered layout is divided into a bottom support unit, a middle support unit and a top support unit, the bottom support unit is used to accommodate the diverter, and a heat extraction layer for dispersing heat to the sensor housing is provided below the diverter; The middle support unit is used to accommodate the zero-sequence current coil. The zero-sequence current coil is arranged around the shunt. The material of the zero-sequence current coil is a nanocrystalline magnetic core. The sensitivity of the zero-sequence current coil is within 0.1 mA for AC and DC. The zero-sequence current coil is isolated from the shunt by a magnetic shielding material. The top support unit is used to accommodate the simulated leakage module, the leakage detection module and the current measurement module. The simulated leakage module, the leakage detection module and the current measurement module are installed together on a PCB, and a thermocouple is arranged on the back of the PCB. The bottom support unit, the middle support unit and the top support unit are electrically connected by flat cables to ensure stable and reliable signal transmission while minimizing the occupied space. At the same time, the use of a vertical layered layout can avoid signal delay or attenuation caused by long-distance routing in a planar layout.

[0007] Preferably, the diverter further comprises: The AC / DC separation unit is used to determine and distinguish whether the input current is an AC signal or a DC signal, separate the mixed signal into a DC component and an AC component, and convert the AC signal into an effective value to ensure accurate measurement of non-sinusoidal waves; The primary conversion unit is used to convert the input AC signal into a DC signal and adapt to bidirectional current transmission.

[0008] Preferably, the current measurement module further comprises: The enhancement unit is used to amplify the tiny voltage signal existing at both ends of the shunt, and amplify the differential voltage signal at both ends of the shunt to the range of ADC sampling, so that it can cooperate with the ADC for analog-to-digital conversion, eliminate common-mode noise, and improve the signal-to-noise ratio; A secondary conversion unit is used to convert analog signals into digital signals; wherein the low-speed high-precision ADC is used for DC signal sampling, with a resolution of 23 bits or more and a sampling rate of 1 kSPS or less; the high-speed ADC is used for AC signal capture, with a sampling rate of 104 kSPS or more and a resolution of 15 bits or more; The core processing unit is used to calculate the actual current value based on the resistance and voltage, and to perform the temperature compensation algorithm; The output interface unit is used to perform multiple types of output modes to meet the usage requirements of different scenarios.

[0009] Preferably, the shunt is made of a thin film shunt or a thick film alloy material, has a resistance of 55 μΩ, and a maximum current carrying capacity of 110A DC or 60A AC.

[0010] Preferably, the current measurement module uses a DC offset compensation circuit and a temperature-current joint compensation algorithm to eliminate DC zero drift and correct the resistance change of the shunt, reduce the measurement error of the AC signal and the DC signal, and the error deviation value is 1.2%FS.

[0011] Preferably, the leakage detection module and the current measurement module are integrated into a single ASIC chip, and support the output of digital quantity, analog quantity and communication signal; The ASIC chip is provided with an analog unit, a digital unit and an isolation belt. The analog unit is used to amplify and filter the residual current signal in the leakage detection module, simulate the leakage signal injection circuit, and perform voltage signal conditioning on the current measurement module. The digital unit is used to perform threshold comparison and early warning signal generation on the leakage detection module, perform AC and DC data fusion and temperature compensation on the current measurement module. The analog unit and the digital unit are isolated by the isolation belt.

[0012] Preferably, the interior of the housing of the sensor is filled with thermally conductive silica gel.

[0013] Preferably, the process of setting the spraying thickness of the heat dissipation coating includes: Extracting the heat dissipation coating spraying area of ​​the housing surface of the sensor; Retrieve the thermal conductivity coefficient corresponding to the coating material of the heat dissipation coating; Retrieve the corresponding maximum allowable operating temperature value during the sensor design process and the maximum and minimum heating rates during the sensor operation process; Obtaining a thickness correction coefficient according to a maximum temperature rise rate and a minimum temperature rise rate during operation of the sensor; The thickness correction coefficient is obtained by the following formula:

[0014] Where s represents the thickness correction factor; Δt max and Δt min Indicates the maximum and minimum heating rates during the operation of the sensor; T x02 and T x01 They represent the maximum temperature and minimum temperature of the temperature range of the sensor during the heating stage corresponding to the maximum heating rate; T y02 and T y01 They represent the maximum and minimum temperature values ​​of the temperature range of the sensor during the heating stage corresponding to the minimum heating rate; T max Indicates the maximum allowable operating temperature value; Retrieve the preset thickness correction coefficient reference value; Normalizing the thickness correction coefficient using a preset thickness correction coefficient reference value so that the thickness correction coefficient is projected to the interval (-1, 1) to obtain a normalized thickness correction coefficient; The spray thickness of the heat dissipation coating is set by using the normalized thickness correction coefficient combined with the heat dissipation coating spray area on the shell surface and the thermal conductivity corresponding to the coating material; The spray thickness of the heat dissipation coating is obtained by the following formula:

[0015] Wherein, d represents the spraying thickness of the heat dissipation coating; d0 represents the preset reference spraying thickness of the heat dissipation coating; s g represents the thickness correction coefficient after normalization; A represents the heat dissipation coating spraying area on the shell surface; x represents the thermal conductivity corresponding to the coating material; Q represents the maximum heat dissipation corresponding to the reference spraying thickness of the heat dissipation coating within the heat dissipation coating spraying area on the shell surface; T c Indicates the maximum temperature difference on the shell surface during sensor operation.

[0016] Preferably, the leakage detection module further includes a Hall element, which is connected in parallel with the zero-sequence current coil and is used to directly detect the magnetic field change of the DC residual current, thereby solving the problem that the traditional transformer cannot measure DC.

[0017] Preferably, the sensor supports single-phase or three-phase current detection, and the internal connection line adopts a flexible printed circuit.

[0018] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention arranges the shunt, the zero-sequence current coil, the simulated leakage module, the leakage detection module and the current measurement module in a vertical layered layout, reduces the plane occupied space by vertical stacking, integrates the current measurement module and the leakage detection module into one ASIC, reduces the need for additional circuit boards, and further reduces the overall volume, making the overall size of the sensor more compact, so that it can be used in smaller industrial facilities, optimizes the internal wiring, reduces signal delay or attenuation, and improves the stability and reliability of the system.

[0019] 2. The present invention realizes accurate detection of AC and DC by integrating efficient shunts and signal processing technology. The shunt is used to measure the voltage generated by the current. DC is measured directly, while AC is first converted into DC form. The enhancement unit amplifies the weak voltage signal and eliminates noise. Then, the low-speed and high-precision ADC is used for DC signal sampling, and the high-speed ADC is used to capture AC signals. The core processing unit calculates the actual current value based on the shunt resistance and temperature compensation data to ensure accuracy and stability under various working conditions, thereby realizing comprehensive detection of AC and DC currents. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the overall circuit of the sensor of the present invention; Figure 2 It is a schematic diagram of the shunt and current measurement module of the present invention.

[0021] In the figure: 1. shunt; 2. conductor; 3. zero-sequence current coil; 4. leakage simulation module; 5. thermocouple; 6. wire; 7. leakage detection module; 8. current measurement module. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] In the prior art, sensors need to use two magnetic rings to measure residual current and rated current respectively. However, stacking two magnetic rings together will make the sensor larger in size, and the sensor can only measure AC but not DC. To solve the above problems, please refer to Figure 1-2 , this embodiment provides the following technical solutions: A composite current detection sensor, comprising the following components: The shunt 1 is used to obtain the current flowing through the conductor 2 through the voltage at both ends, and forms a loop with the conductor 2, and the loop passes through the zero-sequence current coil 3; Zero-sequence current coil 3, used to detect residual current; The leakage detection module 7 is connected to the zero-sequence current coil 3 and is used to obtain the residual current signal of the alternating current or direct current through the zero-sequence current coil 3, analyze the residual current and output a leakage warning signal; the leakage detection module 7 includes a Hall element, which is connected in parallel with the zero-sequence current coil 3 and is used to directly detect the magnetic field change of the DC residual current, thereby solving the problem that the traditional mutual inductor cannot measure the DC, and greatly expanding the application range of the sensor; The current measurement module 8 is connected to the two ends of the shunt 1 through the wire 6, and is used to collect and amplify the voltage signals at the two ends of the shunt 1, sample the DC signal through the low-speed high-precision ADC and capture the AC signal through the high-speed ADC, and calculate the current value of the AC or DC power according to the resistance value and temperature compensation data of the shunt 1; the current measurement module 8 uses a DC offset compensation circuit and a temperature-current joint compensation algorithm to eliminate the DC zero drift and correct the resistance change of the shunt 1, reduce the measurement error of the AC signal and the DC signal, and the error deviation value is 1.2%FS; The simulation leakage module 4 is used to detect whether the zero-sequence current coil 3 and the leakage detection module 7 are working normally, ensuring the reliability of the system and preventing leakage detection due to module failure; Thermocouple 5, used to monitor the temperature of shunt 1 and provide temperature compensation signal to current measurement module 8, and adjust the measurement result by using compensation algorithm based on temperature data to offset the error caused by temperature change, so as to effectively improve the measurement accuracy; In order to solve the problem that the sensor size is too large when two detection magnetic rings are stacked together when measuring residual current and rated current, we propose to arrange the shunt 1, zero-sequence current coil 3, simulated leakage module 4, leakage detection module 7 and current measurement module 8 in layers vertically. This design can reduce the sensor plane area, make the module distribution more concentrated, and facilitate the subsequent installation of the sensor. On the other hand, it helps to isolate the modules and reduce electromagnetic interference. Specifically, the vertical layered layout is divided into a bottom support unit, a middle support unit and a top support unit. The bottom support unit serves as a heat dissipation layer and a current carrying layer, and is installed with a shunt 1. The shunt 1 is made of a thin film shunt or a thick film alloy material, and has a resistance of 55 μΩ and a maximum current carrying capacity of 110A DC or 60A AC. A heat extraction layer for dispersing heat to the sensor housing is provided below the shunt 1, and the heat is quickly extracted from the sensor in combination with thermal conductive silica gel and a heat dissipation coating. The middle support unit is used to accommodate the zero-sequence current coil 3. The zero-sequence current coil 3 is arranged around the shunt 1. The material of the zero-sequence current coil 3 is a nanocrystalline magnetic core. The sensitivity of the zero-sequence current coil 3 is within 0.1 mA of AC and DC. The zero-sequence current coil 3 is isolated from the shunt 1 by a magnetic shielding material to effectively prevent magnetic field interference. The top support unit is used to accommodate the simulated leakage module 4, the leakage detection module 7 and the current measurement module 8. The simulated leakage module 4, the leakage detection module 7 and the current measurement module 8 are installed together on a PCB, and a thermocouple 5 is arranged on the back of the PCB; There are several vertical through holes arranged on the partitions between the bottom support unit, the middle support unit and the top support unit. During installation, flat cables are used to penetrate the vertical through holes to make electrical connections between components, ensuring stable and reliable signal transmission while minimizing the occupied space. At the same time, the use of a vertical layered layout can avoid signal delays or attenuation caused by long-distance routing in a planar layout.

[0024] In addition, in order to reduce the occupied volume of the sensor, the leakage detection module 7 and the current measurement module 8 are integrated into a single ASIC chip. The ASIC chip realizes the integration of the functions of the leakage detection module 7 and the current measurement module 8, and at the same time can achieve the effect of improving the signal transmission speed and processing speed, and supports the output of digital quantity, analog quantity and communication signal; The ASIC chip is provided with an analog unit, a digital unit and an isolation belt. The analog unit is used to amplify and filter the residual current signal in the leakage detection module 7, and simulate the leakage signal injection circuit, and perform voltage signal conditioning on the current measurement module 8. The digital unit is used to perform threshold comparison and early warning signal generation on the leakage detection module 7, and perform AC and DC data fusion and temperature compensation on the current measurement module 8. The analog unit and the digital unit are isolated from each other by an isolation belt to avoid mutual interference.

[0025] In order to meet the measurement requirements of mixed current, that is, to support accurate separation and measurement of AC, DC or non-sinusoidal wave signals at the same time, the shunt 1 is further provided with: The AC / DC separation unit is used to determine and distinguish whether the input current is an AC signal or a DC signal, separate the mixed signal into a DC component and an AC component, use a low-pass filter to extract the DC signal in the DC path, and use a high-pass filter in the AC path to isolate the DC bias, and convert the AC signal into an effective value, and ensure accurate measurement of non-sinusoidal waves through a converter; The primary conversion unit is used to convert the input AC signal into a DC signal and adapt to bidirectional current transmission.

[0026] The current measurement module 8 further comprises: The enhancement unit is used to amplify the tiny voltage signal at both ends of the shunt. A differential amplifier can be used here to amplify the differential voltage signal at both ends of the shunt 1 to the range of ADC sampling, so that it can cooperate with the ADC for analog-to-digital conversion, eliminate common-mode noise, and improve the signal-to-noise ratio. At the same time, the gain needs to be dynamically adjusted to facilitate adaptation to currents of different sizes. A secondary conversion unit is used to convert analog signals into digital signals; wherein the low-speed high-precision ADC is used to collect DC signals, with a resolution of 23 bits or more and a sampling rate of 1 kSPS or less; the high-speed ADC is used to collect AC signals, with a sampling rate of 104 kSPS or more and a resolution of 15 bits or more; The core processing unit is used to calculate the actual current value based on the resistance and voltage, and to perform the temperature compensation algorithm; The output interface unit is used to perform multiple types of output modes to meet the usage requirements of different scenarios.

[0027] The interior of the sensor housing is filled with thermally conductive silica gel, and the surface of the housing is provided with a heat dissipation coating for quickly conducting away the heat generated by the diverter 1 through a heat conduction path.

[0028] Specifically, the process of setting the spraying thickness of the heat dissipation coating includes: Extracting the heat dissipation coating spraying area of ​​the housing surface of the sensor; Retrieve the thermal conductivity coefficient corresponding to the coating material of the heat dissipation coating; Retrieve the corresponding maximum allowable operating temperature value during the sensor design process and the maximum and minimum heating rates during the sensor operation process; Obtaining a thickness correction coefficient according to a maximum temperature rise rate and a minimum temperature rise rate during operation of the sensor; The thickness correction coefficient is obtained by the following formula:

[0029] Where s represents the thickness correction factor; Δt max and Δtmin Indicates the maximum and minimum heating rates during the operation of the sensor; T x02 and T x01 They represent the maximum temperature and minimum temperature of the temperature range of the sensor during the heating stage corresponding to the maximum heating rate; T y02 and T y01 They represent the maximum and minimum temperature values ​​of the temperature range of the sensor during the heating stage corresponding to the minimum heating rate; T max Indicates the maximum allowable operating temperature value; Retrieving a preset thickness correction coefficient reference value; wherein the thickness correction coefficient reference value is determined by the actual specifications of the sensor and the engineering application scenario, and is used to project the thickness correction coefficient into the interval (-1, 1); Normalizing the thickness correction coefficient using a preset thickness correction coefficient reference value so that the thickness correction coefficient is projected to the interval (-1, 1) to obtain a normalized thickness correction coefficient; The spray thickness of the heat dissipation coating is set by using the normalized thickness correction coefficient combined with the heat dissipation coating spray area on the shell surface and the thermal conductivity corresponding to the coating material; The spray thickness of the heat dissipation coating is obtained by the following formula:

[0030] Wherein, d represents the spraying thickness of the heat dissipation coating; d0 represents the preset reference spraying thickness of the heat dissipation coating; s g represents the thickness correction coefficient after normalization; A represents the heat dissipation coating spraying area on the shell surface; x represents the thermal conductivity corresponding to the coating material; Q represents the maximum heat dissipation corresponding to the reference spraying thickness of the heat dissipation coating within the heat dissipation coating spraying area on the shell surface; T c Indicates the maximum temperature difference on the shell surface during sensor operation.

[0031] The sensor supports single-phase or three-phase current detection, and the internal connection line adopts flexible printed circuit.

[0032] The sensor is provided with a power management module for providing high-stability power supply to the components in the sensor. The power management module is provided with a power isolation unit to prevent interference from the ground loop. A low-power consumption mode is also provided, that is, the circuit in the idle state is shut down in the standby state to reduce power consumption.

[0033] Working principle: When current passes through the shunt 1, according to Ohm's law, a voltage drop proportional to the current flowing through will be generated at both ends of the shunt. The current measurement module 8 is connected to the two ends of the shunt 1 through the wire 6 to collect the voltage signal. The enhancement unit amplifies the tiny voltage signal at both ends of the shunt 1 and eliminates the common mode noise to improve the signal-to-noise ratio; for DC signals, a low-speed and high-precision ADC is used for sampling, and for AC signals, a high-speed ADC is used to capture high-frequency components; the core processing unit calculates the actual current value based on the specific resistance value and temperature compensation data of the shunt 1, and executes the temperature compensation algorithm to ensure the measurement accuracy under different temperature conditions.

[0034] When an abnormal current is detected, the zero-sequence current coil 3 transmits a signal to the leakage detection module 7. The leakage detection module 7 analyzes these signals and compares them with a preset threshold value. Once a residual current exceeding the threshold value is found, a leakage warning signal is issued to implement the leakage protection function; the simulated leakage module 4 is used to regularly detect the operating status of the entire system to ensure that the leakage detection module 7 and the current measurement module 8 work normally to avoid false alarms or missed alarms; the thermocouple 5 monitors the operating temperature of the shunt and provides a compensation signal to the current measurement module 8. Based on the measured temperature data, a compensation algorithm is used to adjust the measurement result to offset the error caused by temperature changes and ensure measurement accuracy.

[0035] The sensor body adopts a vertical layered layout. The bottom support unit accommodates the shunt 1, the middle support unit places the zero-sequence current coil 3, and the top support unit integrates the analog leakage module 4, the leakage detection module 7 and the current measurement module 8. The layers are electrically connected through flat cables, which not only reduces the occupied space, but also avoids the signal delay or attenuation caused by long-distance wiring that may be caused by the planar layout.

[0036] On the other hand, by comprehensively considering the spraying area of ​​the heat dissipation coating on the surface of the sensor shell, the thermal conductivity of the coating material, the maximum allowable operating temperature of the sensor, and the heating rate during operation, the technical solution can more accurately set the spraying thickness of the heat dissipation coating. The above technical solution can effectively ensure that the sensor maintains a stable temperature during operation, thereby improving its performance and reliability. By optimizing the thickness of the heat dissipation coating, the heat dissipation efficiency of the sensor is effectively improved, thereby reducing the risk of performance degradation or failure due to overheating. At the same time, the above technical solution takes into account the heating rate of the sensor during operation, and adjusts the thickness of the heat dissipation coating through the thickness correction coefficient, so that the sensor can better adapt to different working environments and conditions, such as maintaining stable performance in different temperature ranges or heating rates. In addition, by accurately controlling the thickness of the heat dissipation coating, the heat dissipation efficiency of the sensor is optimized to the greatest extent, thereby reducing the damage to the sensor due to overheating, thereby extending its service life. This is especially important for sensors that require long-term stable operation.

[0037] The above technical solution provides a systematic method to set the spray thickness of the heat dissipation coating, which simplifies the design and production process of the sensor. Through clear formulas and steps, the debugging time in the coating thickness setting process is effectively reduced, thereby improving the sensor production efficiency. Therefore, the above technical solution significantly improves the performance and reliability of the sensor through the technical effects of accurately controlling the thickness of the heat dissipation coating, improving heat dissipation efficiency, enhancing the adaptability of the sensor, improving durability, and simplifying the design and production process.

[0038] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0039] While the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that many changes, modifications, substitutions and variations can be made to the embodiments without departing from the principles and spirit of the invention.

Claims

1. A composite current detection sensor, characterized in that: Includes the following components: A shunt (1) for obtaining a current flowing through the shunt by means of a voltage at both ends and forming a loop with a conductor (2), wherein the loop passes through a zero-sequence current coil (3); A zero-sequence current coil (3) for detecting residual current; A leakage detection module (7) connected to the zero-sequence current coil (3) and used to obtain a residual current signal of alternating current or direct current through the zero-sequence current coil (3), analyze the residual current and output a leakage warning signal; A current measurement module (8) connected to two ends of the shunt (1) via a wire (6) and used for collecting and amplifying voltage signals at the two ends of the shunt (1); A simulated leakage module (4) is used to detect whether the zero-sequence current coil (3) and the leakage detection module (7) are working normally; A thermocouple (5) is used to monitor the temperature of the shunt (1) and provide a temperature compensation signal to the current measurement module (8), and to adjust the measurement result using a compensation algorithm based on the temperature data; The shunt (1), the zero-sequence current coil (3), the simulated leakage module (4), the leakage detection module (7) and the current measurement module (8) are arranged in a vertical layered manner; The outer shell surface of the sensor is provided with a heat dissipation coating, and the spraying thickness of the heat dissipation coating is set based on the temperature rise parameters and the thermal conductivity properties of the material when the sensor is running.

2. A composite current detection sensor according to claim 1, characterized in that: The longitudinal layered layout is divided into a bottom support unit, a middle support unit and a top support unit, the bottom support unit is used to accommodate the diverter (1), and a heat extraction layer for dispersing heat to the sensor housing is provided below the diverter (1); The middle support unit is used to accommodate a zero-sequence current coil (3). The zero-sequence current coil (3) is arranged around the top of the shunt (1). The material of the zero-sequence current coil (3) is a nanocrystalline magnetic core. The sensitivity of the zero-sequence current coil (3) is within 0.1 mA for AC and DC. The zero-sequence current coil (3) is isolated from the shunt (1) by a magnetic shielding material. The top support unit is used to accommodate the simulated leakage module (4), the leakage detection module (7) and the current measurement module (8); the simulated leakage module (4), the leakage detection module (7) and the current measurement module (8) are installed together on a PCB, and a thermocouple (5) is arranged on the back of the PCB; The bottom support unit, the middle support unit and the top support unit are electrically connected via a flat cable.

3. A composite current detection sensor according to claim 2, characterized in that: The shunt (1) is made of a thin film shunt or a thick film alloy material, has a resistance of 55 μΩ, and a maximum current carrying capacity of 110A DC or 60A AC. The shunt (1) further comprises: The AC / DC separation unit is used to determine and distinguish whether the input current is an AC signal or a DC signal, separate the mixed signal into a DC component and an AC component, and convert the AC signal into an effective value; The primary conversion unit is used to convert the input AC signal into a DC signal and adapt to bidirectional current transmission.

4. A composite current detection sensor according to claim 3, characterized in that: The current measurement module (8) further comprises: The enhancement unit is used to amplify the tiny voltage signal existing at both ends of the shunt, amplify the differential voltage signal at both ends of the shunt (1) to the sampling range of the ADC, so that it can cooperate with the ADC to perform analog-to-digital conversion and eliminate common-mode noise; A secondary conversion unit is used to convert analog signals into digital signals; wherein the low-speed high-precision ADC is used for DC signal sampling, with a resolution of 23 bits or more and a sampling rate of 1 kSPS or less; the high-speed ADC is used for AC signal capture, with a sampling rate of 104 kSPS or more and a resolution of 15 bits or more; The core processing unit is used to calculate the actual current value based on the resistance and voltage, and to perform the temperature compensation algorithm; The output interface unit is used to perform multiple types of output modes.

5. A composite current detection sensor according to claim 4, characterized in that: The current measurement module (8) samples DC signals through a low-speed high-precision ADC and captures AC signals through a high-speed ADC, and calculates the current value of the AC or DC current based on the resistance value of the shunt (1) and temperature compensation data; The current measurement module (8) uses a DC offset compensation circuit and a temperature-current joint compensation algorithm to eliminate DC zero drift and correct the resistance change of the shunt (1), thereby reducing the measurement error of the AC signal and the DC signal, and the error deviation value is 1.2% FS.

6. A composite current detection sensor according to claim 5, characterized in that: The leakage detection module (7) and the current measurement module (8) are integrated into a single ASIC chip and support the output of digital quantities, analog quantities and communication signals; The ASIC chip is provided with an analog unit, a digital unit and an isolation belt. The analog unit is used to amplify and filter the residual current signal in the leakage detection module (7), and simulate the leakage signal injection circuit, and perform voltage signal conditioning on the current measurement module (8). The digital unit is used to perform threshold comparison and early warning signal generation on the leakage detection module (7), and perform AC and DC data fusion and temperature compensation on the current measurement module (8). The analog unit and the digital unit are isolated by the isolation belt.

7. A composite current detection sensor according to claim 6, characterized in that: The interior of the housing of the sensor is filled with thermally conductive silica gel.

8. A composite current detection sensor according to claim 7, characterized in that: The spraying thickness setting process of the heat dissipation coating includes: Extracting the heat dissipation coating spraying area of ​​the housing surface of the sensor; Retrieve the thermal conductivity of the coating material of the heat dissipation coating; Retrieve the corresponding maximum allowable operating temperature value during the sensor design process and the maximum and minimum heating rates during the sensor operation process; Obtaining a thickness correction coefficient according to a maximum temperature rise rate and a minimum temperature rise rate during operation of the sensor; Retrieve the preset thickness correction coefficient reference value; Normalizing the thickness correction coefficient using a preset thickness correction coefficient reference value so that the thickness correction coefficient is projected to the interval (-1, 1) to obtain a normalized thickness correction coefficient; The spray thickness of the heat dissipation coating is set by using the normalized thickness correction coefficient combined with the heat dissipation coating spray area on the shell surface and the thermal conductivity corresponding to the coating material.

9. A composite current detection sensor according to claim 8, characterized in that: The leakage detection module (7) further comprises a Hall element, which is connected in parallel with the zero-sequence current coil (3) and is used to directly detect the change in the magnetic field of the DC residual current.

10. The composite current detection sensor according to claim 9, characterized in that: The sensor supports single-phase or three-phase current detection.

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