A composite current detection sensor

Abstract

The present invention discloses a composite current detection sensor, belonging to the technical field of current detection and protection. A composite current detection sensor includes a shunt, a zero-sequence current coil, a leakage detection module, a current measurement, an analog leakage module, and a thermocouple. Among them, the shunt, the zero-sequence current coil, the analog leakage module, the leakage detection module, and the current measurement module adopt a longitudinal layered layout, and an integrated and efficient shunt and signal processing technology are set to achieve accurate detection of alternating current and direct current. The present invention solves the problems that the size of the existing sensor becomes larger, and the sensor can only measure alternating current without the function of measuring direct current. The present invention can not only reduce the occupied space of the sensor, realize the installation and deployment in a smaller space, but also achieve accurate detection of alternating current and direct current at the same time.

Description

Technical Field

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

[0002] In modern industrial facilities and power systems, current detection sensors are key components to ensure the safe operation of electrical equipment and prevent faults. Traditional current detection technologies mainly rely on independent residual current sensors and current sensors to respectively achieve the functions of leakage protection, current measurement, and overcurrent protection. However, the existing technical solutions have obvious limitations, specifically manifested as follows:

[0003] The volume of traditional sensors and the space they occupy are relatively large. Usually, two independent devices are required to measure the residual current and rated current respectively, which results in a relatively large overall size of the sensor and is difficult to adapt to application scenarios with strict installation space limitations. Especially in compact devices or high-density wiring environments, large sensors not only increase the installation difficulty but may also affect the layout and performance of other components.

[0004] Most traditional sensors can only detect alternating current or direct current singly and cannot meet the requirements of both at the same time. Since both alternating current and direct current power sources often exist in industrial applications, the lack of a sensor that can effectively process AC-DC mixed signals has become a major challenge in practical applications. Especially in new energy fields (such as solar power generation systems) and electric vehicle charging facilities, etc., the simultaneous and accurate monitoring of AC and DC currents is particularly important. Summary of the Invention

[0005] The purpose of the present invention is to provide a composite current detection sensor. By longitudinally arranging the shunt, zero-sequence current coil, analog leakage module, leakage detection module, and current measurement module in a layered layout, the planar occupied space is reduced through a vertically stacked method. Through the integration of an efficient shunt and signal processing technology, the accurate detection of alternating current and direct current is achieved. It can not only complete the installation and deployment in a smaller space but also achieve the simultaneous and accurate detection of alternating current and direct current to meet the diverse requirements in modern complex electrical environments, and solve the problems raised in the above background art.

[0006] To achieve the above purpose, the present invention provides the following technical solutions:

[0007] A composite current detection sensor includes the following components:

[0008] A shunt, which is used to obtain the flowing current through the voltage at both ends and form a loop with a conductor, and the loop passes through a zero-sequence current coil;

[0009] A zero-sequence current coil, which is used to detect the residual current;

[0010] A leakage detection module, connected to the zero-sequence current coil, is configured to obtain a residual current signal of alternating current or direct current through the zero-sequence current coil, analyze the residual current and output a leakage warning signal;

[0011] A current measurement module, connected to both ends of the shunt via a wire, is configured to collect and amplify the voltage signal across the shunt, sample the DC signal through a low-speed high-precision ADC and capture the AC signal through a high-speed ADC, and calculate the current value of alternating current or direct current based on the resistance value of the shunt and temperature compensation data;

[0012] An analog leakage module is configured to detect whether the zero-sequence current coil and the leakage detection module are working properly;

[0013] A thermocouple is configured to monitor the temperature of the shunt and provide a temperature compensation signal to the current measurement module, and adjust the measurement result using a compensation algorithm based on the temperature data to offset the error caused by temperature changes;

[0014] Wherein, the shunt, the zero-sequence current coil, the analog leakage module, the leakage detection module and the current measurement module adopt a longitudinal layered layout;

[0015] A heat dissipation coating is provided on the outer surface of the housing of the sensor, and the spraying thickness of the heat dissipation coating is set based on the temperature rise parameter during the operation of the sensor and the material thermal conductivity property.

[0016] 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 shunt, and a heat dissipation layer for dispersing heat to the sensor housing is provided below the shunt;

[0017] The middle support unit is used to accommodate the zero-sequence current coil. The zero-sequence current coil is disposed around the shunt. The material of the zero-sequence current coil is selected as a nanocrystalline magnetic core. The sensitivity of the zero-sequence current coil is within 0.1 mA for both AC and DC. The zero-sequence current coil and the shunt are isolated by a magnetic shielding material;

[0018] The top support unit is used to accommodate the analog leakage module, the leakage detection module and the current measurement module. The analog leakage module, the leakage detection module and the current measurement module are jointly installed on a PCB, and the thermocouple is arranged on the back of the PCB;

[0019] The bottom support unit, the middle support unit and the top support unit are electrically connected by a flat cable, which can ensure stable and reliable signal transmission while minimizing the occupied space. At the same time, using the longitudinal layered layout can avoid the signal delay or attenuation caused by long-distance wiring in the planar layout.

[0020] Preferably, the shunt further includes:

[0021] An AC / DC separation unit for determining and differentiating whether the input current is an AC signal or a DC signal, separating the mixed signal into a DC component and an AC component, and converting the AC signal into an effective value to ensure accurate measurement of non-sinusoidal waves;

[0022] A primary conversion unit for converting the input AC signal into a DC signal and adapting to bidirectional current transmission.

[0023] Preferably, the current measurement module further includes:

[0024] An enhancement unit for amplifying the tiny voltage signal existing across the shunt, amplifying the differential voltage signal across the shunt to the range of ADC sampling, enabling it to cooperate with the ADC for analog-to-digital conversion, and eliminating common-mode noise to improve the signal-to-noise ratio;

[0025] A secondary conversion unit for converting the analog signal into a digital signal; among them, a low-speed high-precision ADC is used for DC signal sampling, with a resolution of 23 bits or more and a sampling rate of 1kSPS or less; a high-speed ADC is used for AC signal capture, with a sampling rate of 104kSPS or more and a resolution of 15 bits or more;

[0026] A core processing unit for calculating the actual current value based on the resistance value and voltage and executing a temperature compensation algorithm;

[0027] An output interface unit for performing multiple types of output modes to meet the usage requirements of different scenarios.

[0028] Preferably, the shunt is made of a thin-film shunt or a thick-film alloy material, with a resistance value of 55 μΩ and a maximum current-carrying capacity of 110 A DC or 60 A AC.

[0029] Preferably, the current measurement module uses a DC offset compensation circuit and a temperature-current combined compensation algorithm to eliminate DC zero drift and correct the resistance value change of the shunt, reducing the measurement error between the AC signal and the DC signal, with an error deviation value of 1.2% FS.

[0030] Preferably, the leakage detection module and the current measurement module are integrated into a single ASIC chip and support the output of digital, analog, and communication signals;

[0031] An analog unit, a digital unit, and an isolation band are provided on the ASIC chip. The analog unit is used to amplify and filter the residual current signal in the leakage detection module, inject an analog leakage signal into the circuit, and condition the voltage signal of the current measurement module. The digital unit is used to perform threshold comparison on the leakage detection module and generate an early warning signal, and perform AC / DC data fusion and temperature compensation on the current measurement module. The analog unit and the digital unit are isolated by the isolation band.

[0032] Preferably, the inside of the housing of the sensor is filled with thermal conductive silica gel.

[0033] Preferably, the process of setting the spraying thickness of the heat dissipation coating includes:

[0034] Extract the spraying area of the heat dissipation coating on the surface of the housing of the sensor;

[0035] Retrieve the thermal conductivity coefficient corresponding to the coating material of the heat dissipation coating;

[0036] Retrieve the maximum allowable operating temperature value corresponding to the sensor design process, the maximum heating rate and the minimum heating rate during the operation of the sensor;

[0037] Obtain a thickness correction coefficient according to the maximum heating rate and the minimum heating rate during the operation of the sensor;

[0038] Among them, the thickness correction coefficient is obtained through the following formula:

[0039]

[0040] Among them, s represents the thickness correction coefficient; Δt max and Δt min represent the maximum heating rate and the minimum heating rate during the operation of the sensor; T x02 and T x01 respectively represent the maximum temperature and the minimum temperature of the temperature range of the sensor operation heating stage corresponding to the maximum heating rate; T y02 and T y01 respectively represent the maximum temperature and the minimum temperature of the temperature range of the sensor operation heating stage corresponding to the minimum heating rate; T max represents the maximum allowable operating temperature value;

[0041] Retrieve the preset thickness correction coefficient reference value;

[0042] Normalize the thickness correction coefficient using the preset thickness correction coefficient reference value so that the thickness correction coefficient is projected onto the interval (-1, 1) to obtain the normalized thickness correction coefficient;

[0043] Set the spraying thickness of the heat dissipation coating by combining the thickness correction coefficient after normalization with the spraying area of the heat dissipation coating on the outer shell surface and the thermal conductivity corresponding to the coating material;

[0044] Among them, the spraying thickness of the heat dissipation coating is obtained by the following formula:

[0045]

[0046] Among them, d represents the spraying thickness of the heat dissipation coating; d0 represents the reference spraying thickness of the preset heat dissipation coating; s g represents the thickness correction coefficient after normalization; A represents the spraying area of the heat dissipation coating on the outer shell surface; x represents the thermal conductivity corresponding to the coating material; Q represents the maximum heat dissipation corresponding to the heat dissipation coating with the reference spraying thickness within the spraying area of the heat dissipation coating on the outer shell surface; T c represents the maximum temperature difference on the outer shell surface corresponding to the operation of the sensor.

[0047] Preferably, the leakage detection module further includes a Hall element, and the Hall element is connected in parallel with the zero-sequence current coil for directly detecting the magnetic field change of the DC residual current, solving the problem that traditional current transformers cannot measure DC.

[0048] Preferably, the sensor supports single-phase or three-phase current detection modes, and the internal connection lines adopt flexible printed circuits.

[0049] Compared with the prior art, the beneficial effects of the present invention are:

[0050] 1. By longitudinally arranging the shunt, zero-sequence current coil, analog leakage module, leakage detection module, and current measurement module in a hierarchical layout, the present invention reduces the planar occupied space by vertical stacking, integrates the current measurement module and the leakage detection module into an ASIC, reduces the need for additional circuit boards, further reduces the overall volume, makes the overall size of the sensor more compact, can be used inside industrial facilities with a smaller volume, and optimizes the internal wiring, reduces signal delay or attenuation, and improves the stability and reliability of the system.

[0051] 2. The present invention realizes the accurate detection of alternating current and direct current by integrating an efficient shunt and signal processing technology. The shunt is used to measure the voltage generated by the current, directly measure the direct current, and for the alternating current, first convert it into a DC form, the enhancement unit amplifies the weak voltage signal and eliminates noise, then the low-speed high-precision ADC is used for DC signal sampling, the high-speed ADC is used to capture the AC signal, and the core processing unit calculates the actual current value based on the shunt resistance value and temperature compensation data to ensure accuracy and stability under various working conditions, thereby realizing the comprehensive detection of alternating and direct current. Brief Description of the Drawings

[0052] Figure 1 This is a schematic diagram of the overall circuit of the sensor of the present invention;

[0053] Figure 2 This is a schematic diagram of the shunt and current measurement module of the present invention.

[0054] In the figure: 1. Shunt; 2. Conductor; 3. Zero-sequence current coil; 4. Analog leakage module; 5. Thermocouple; 6. Wire; 7. Leakage detection module; 8. Current measurement module. Detailed Embodiment

[0055] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0056] In the prior art, two magnetic rings are required for sensors to measure the residual current and the rated current respectively. Stacking two magnetic rings together will increase the size of the sensor, and the sensor can only measure alternating current and does not have the function of measuring direct current. To solve the above problems, please refer to Figure 1-2 , the following technical solutions are provided in this embodiment:

[0057] A composite current detection sensor includes the following components:

[0058] A shunt 1, which is used to obtain the flowing current through the voltage at both ends and form a loop with a conductor 2, and the loop passes through a zero-sequence current coil 3;

[0059] A zero-sequence current coil 3, which is used to detect the residual current;

[0060] A leakage detection module 7, which is connected to the zero-sequence current coil 3 and is used to obtain the 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; the leakage detection module 7 includes a Hall element, and the Hall element 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, solving the problem that traditional current transformers cannot measure direct current, and greatly expanding the application range of the sensor;

[0061] The current measurement module 8 is connected to both ends of the shunt 1 through a wire 6, and is used to collect and amplify the voltage signal across the shunt 1, sample the DC signal through a low-speed high-precision ADC and capture the AC signal through a high-speed ADC, and calculate the current value of the alternating current or direct current according to the resistance value of the shunt 1 and the temperature compensation data; the current measurement module 8 uses a DC offset compensation circuit and a temperature-current combined compensation algorithm to eliminate the DC zero drift and correct the change in the resistance value of the shunt 1, reducing the measurement error of the AC signal and the DC signal, and the error deviation value is 1.2% FS;

[0062] The analog leakage module 4 is used to detect whether the zero-sequence current coil 3 and the leakage detection module 7 are working properly, ensure the reliability of the system, and prevent missed detection caused by module failures;

[0063] The thermocouple 5 is used to monitor the temperature of the shunt 1 and provide a temperature compensation signal to the current measurement module 8, adjust the measurement result using a compensation algorithm based on the temperature data, and offset the error caused by temperature changes, effectively improving the measurement accuracy;

[0064] In order to solve the problem that when measuring the residual current and the rated current, the method of stacking two detection magnetic rings together will make the occupied volume of the sensor size too large, we propose to arrange the shunt 1, the zero-sequence current coil 3, the analog leakage module 4, the leakage detection module 7 and the current measurement module 8 in a longitudinal layered arrangement. Such a design can, on the one hand, reduce the occupied area of the sensor plane, 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;

[0065] Specifically, the longitudinal 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 the shunt 1 is installed. The shunt 1 is made of a thin-film shunt or a thick-film alloy material, its resistance value is 55 μΩ, and the maximum current-carrying capacity is 110 A DC or 60 A AC. A heat dissipation layer for dispersing heat to the sensor housing is provided below the shunt 1, and the heat is quickly exported from the sensor by combining thermal conductive silicone and a heat dissipation coating;

[0066] 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 selected as a nanocrystalline magnetic core. The sensitivity of the zero-sequence current coil 3 is within 0.1 mA for both AC and DC. The zero-sequence current coil 3 and the shunt 1 are isolated by a magnetic shielding material to effectively prevent magnetic field interference;

[0067] 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 jointly installed on a PCB, and a thermocouple 5 is arranged on the back of the PCB.

[0068] A number of vertical through-holes are arranged and distributed on the interlayers between the bottom support unit, the middle support unit, and the top support unit. When installing, a flat cable is used to pass through the vertical through-holes for electrical connection between components, ensuring stable and reliable signal transmission while minimizing the occupied space. At the same time, the use of a longitudinal layered layout can avoid signal delay or attenuation caused by long-distance wiring in a planar layout.

[0069] In addition, in order to better 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 functions of the leakage detection module 7 and the current measurement module 8 are integrated through the ASIC chip. At the same time, the effect of improving the signal transmission speed and processing speed can be achieved, and the output of digital, analog, and communication signals is supported.

[0070] An analog unit, a digital unit, and an isolation band are provided on the ASIC chip. The analog unit is used to amplify and filter the residual current signal in the leakage detection module 7, and inject a simulated leakage signal into the circuit to condition the voltage signal of the current measurement module 8. The digital unit is used to perform threshold comparison and generate warning signals for the leakage detection module 7, and perform AC / DC data fusion and temperature compensation for the current measurement module 8. The analog unit and the digital unit are isolated by the isolation band to avoid mutual interference.

[0071] To meet the measurement requirements of mixed current, that is, to support the precise separation and measurement of AC, DC, or non-sinusoidal signals simultaneously, the following are further provided in the shunt 1:

[0072] An AC / DC separation unit, which is used to judge 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 the accurate measurement of non-sinusoidal waves through a converter.

[0073] A primary conversion unit, which is used to convert the input AC signal into a DC signal and adapt to bidirectional current transmission.

[0074] The current measurement module 8 further includes:

[0075] An enhancement unit for amplifying the tiny voltage signal existing across the shunt. Here, a differential amplifier can be used to amplify the differential voltage signal across the shunt 1 to the range for ADC sampling, enabling it to cooperate with the ADC for analog-to-digital conversion, eliminating common-mode noise, improving the signal-to-noise ratio, and at the same time, dynamic adjustment of the gain is required to facilitate adaptation to different magnitudes of current;

[0076] A secondary conversion unit for converting the analog signal into a digital signal; among them, a low-speed high-precision ADC is used for the acquisition of DC signals, with a resolution of 23 bits or more, and its sampling rate is 1kSPS or less; a high-speed ADC is used for the acquisition of AC signals, with a sampling rate of 104kSPS or more and a resolution of 15 bits or more;

[0077] A core processing unit for calculating the actual current value based on the resistance value and voltage and executing a temperature compensation algorithm;

[0078] An output interface unit for performing multiple types of output modes to meet the usage requirements of different scenarios.

[0079] The interior of the sensor's housing is filled with thermal conductive silica gel, and a heat dissipation coating is provided on the surface of the housing for quickly conducting out the heat generated by the shunt 1 through the heat conduction path.

[0080] Specifically, the process of setting the spraying thickness of the heat dissipation coating includes:

[0081] Extracting the spraying area of the heat dissipation coating on the surface of the sensor's housing;

[0082] Retrieving the thermal conductivity coefficient corresponding to the coating material of the heat dissipation coating;

[0083] Retrieving the maximum allowable operating temperature value corresponding to the sensor design process and the maximum and minimum heating rate during the sensor operation;

[0084] Obtaining a thickness correction coefficient based on the maximum and minimum heating rate during the sensor operation;

[0085] Among them, the thickness correction coefficient is obtained through the following formula:

[0086]

[0087] Among them, s represents the thickness correction coefficient; Δt max and Δt min represent the maximum and minimum heating rate during the sensor operation; T x02 and T x01 respectively represent the maximum temperature and the minimum temperature of the temperature range of the sensor operation heating stage corresponding to the maximum heating rate; Ty02 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;

[0088] 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);

[0089] 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;

[0090] 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;

[0091] The spray thickness of the heat dissipation coating is obtained by the following formula:

[0092]

[0093] 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.

[0094] The sensor supports single-phase or three-phase current detection, and the internal connection line adopts flexible printed circuit.

[0095] 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.

[0096] Working principle: When current passes through the shunt 1, according to Ohm's law, a voltage drop proportional to the flowing current will be generated across the shunt. The current measurement module 8 is connected to both ends of the shunt 1 through the wire 6 to collect this voltage signal. The enhancement unit amplifies the tiny voltage signal across the shunt 1 and eliminates the common-mode noise to improve the signal-to-noise ratio. For DC signals, a low-speed high-precision ADC is used for sampling, and for AC signals, a high-speed ADC is used to capture the high-frequency components. The core processing unit calculates the actual current value based on the specific resistance value of the shunt 1 and the temperature compensation data, and executes the temperature compensation algorithm to ensure the measurement accuracy under different temperature conditions.

[0097] When an abnormal current is detected, the zero-sequence current coil 3 transmits the signal to the leakage detection module 7. The leakage detection module 7 analyzes these signals and compares them with the preset threshold. Once a residual current exceeding the threshold is found, a leakage warning signal is sent to achieve the leakage protection function. The analog leakage module 4 is used to regularly detect the operating state of the entire system to ensure the normal operation of the leakage detection module 7 and the current measurement module 8, and 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 the measurement accuracy.

[0098] The sensor body is arranged in a longitudinal layered layout. The bottom support unit houses 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. Each layer is electrically connected through a flat cable, which not only reduces the occupied space but also avoids the signal delay or attenuation problems caused by long-distance wiring that may occur in a planar layout.

[0099] On the other hand, by comprehensively considering the spraying area of the heat dissipation coating on the surface of the sensor housing, the thermal conductivity of the coating material, the maximum allowable operating temperature of the sensor, and the heating rate during operation, this technical solution can more accurately set the spraying thickness of the heat dissipation coating. Through the above technical solution, it 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, and further reduces the risk of performance degradation or failure caused by overheating. At the same time, the above technical solution considers 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. And by precisely controlling the thickness of the heat dissipation coating, the heat dissipation efficiency of the sensor is optimized to the greatest extent, and further reduces the damage suffered by the sensor due to overheating, thereby extending its service life. This is particularly important for sensors that need to operate stably for a long time.

[0100] The above technical solution provides a systematic method for setting the spraying thickness of the heat dissipation coating, which simplifies the design and production process of the sensor. Through clear formulas and steps, the debugging time during the coating thickness setting process is effectively reduced, thereby improving the production efficiency of the sensor. Therefore, the above technical solution significantly improves the performance and reliability of the sensor through technical effects such as precisely controlling the thickness of the heat dissipation coating, improving the heat dissipation efficiency, enhancing the adaptability of the sensor, enhancing the durability, and simplifying the design and production process.

[0101] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device.

[0102] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention.

Claims

1. A composite current detection sensor, characterized in that: Includes the following components: A shunt (1) is used to obtain a current flowing through the shunt by means of a voltage at both ends and to form 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) is connected to the zero-sequence current coil (3) and is 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 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, and the vertical layered arrangement 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 shunt (1), the middle support unit is used to accommodate the zero-sequence current coil (3), and 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 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: A heat extraction layer for dispersing heat to the sensor housing is provided below the diverter (1); 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) and the shunt (1) are isolated by a magnetic shielding material; 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 range of ADC sampling, so that it cooperates 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 AC or DC according to 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 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 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. The composite current detection sensor according to claim 8, characterized in that: The leakage detection module (7) also 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.

10. A 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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