A car-grade isolated current sensing device

Abstract

The application discloses a kind of vehicle gauge level isolated current sensing devices, including packaging shell, and built-in current lead, isolation detection module, signal conditioning module, fault monitoring module and communication output module installed in packaging shell inside, built-in current lead, isolation detection module, signal conditioning module, fault monitoring module and communication output module are integrated in packaging shell, realize integrated design, both ends of built-in current lead are fixedly connected with series joint;Signal conditioning link is amplified signal by low-noise amplifier twice, FIR filtering algorithm filters high-frequency electromagnetic noise, and is matched with linear voltage stabilizer to provide stable low-noise power supply, effectively avoid the influence of signal distortion and power supply fluctuation;Each functional module is independently installed on special mounting plate, integrated packaging design reduces external interference, ensure that device continues stable operation in new energy automobile harsh working environment.

Description

Technical Field

[0001] This invention relates to the field of current sensing technology, specifically to an automotive-grade isolated current sensing device. Background Technology

[0002] With the development of the new energy vehicle industry and the popularization of 800V high-voltage platforms, automotive-grade current sensing devices, as core sensing components of power systems, are widely used in high-voltage scenarios such as BMS and motor controllers. Their performance directly affects the control accuracy of the whole vehicle, range estimation and driving safety, and must meet stringent automotive-grade requirements.

[0003] Currently, mainstream devices use shunts or traditional Hall effect sensors, which have several drawbacks: First, they have low measurement accuracy, poor wide-temperature adaptability, large temperature drift error, and weak resistance to stray magnetic field interference, making them unsuitable for high-voltage platforms and high-precision detection requirements. Second, they lack operational stability, have incomplete signal conditioning, scattered module layout, and weak anti-interference capabilities, making them difficult to adapt to the harsh environment of the power compartment. Third, they have delayed fault response and poor safety, with single threshold designs prone to false alarms or untimely responses, and some devices lack complete fault uploading functions, failing to meet functional safety standards. Fourth, they have poor adaptability and practicality, with complex installation, a single output mode, and low integration, which is not conducive to large-scale production. Summary of the Invention

[0004] The purpose of this invention is to provide an automotive-grade isolated current sensing device to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: an automotive-grade isolated current sensing device, comprising a packaged housing, and an internally mounted current conductor, an isolation detection module, a signal conditioning module, a fault monitoring module, and a communication output module installed inside the packaged housing. The internally mounted current conductor, the isolation detection module, the signal conditioning module, the fault monitoring module, and the communication output module are integrated within the packaged housing to achieve an integrated design. Both ends of the internally mounted current conductor are fixedly connected to series connectors.

[0006] Preferably, mounting cylinders are fixedly installed on the top and bottom of the encapsulation shell, and the built-in current conductor is fixedly installed inside the mounting cylinder. The built-in current conductor is made of high conductivity copper material, and the conductor impedance of the built-in current conductor is as low as 0.24mΩ, which can carry DC and AC currents of 0A to 150A.

[0007] Preferably, the isolation detection module includes a magnetic sensor and an ADC converter. The magnetic sensor is located outside the built-in current conductor. Based on the magnetic effect of the current, it senses the magnetic field generated around the built-in current conductor that is proportional to the current and converts it into a weak voltage signal. The ADC converter uses a 16-bit high-precision analog-to-digital converter to read and amplify the weak voltage signal to ensure measurement accuracy.

[0008] Preferably, the signal conditioning module includes a low-noise amplifier, a low-pass filter, and a linear regulator. The low-noise amplifier amplifies the signal converted by the ADC converter a second time. The low-pass filter uses an FIR filtering algorithm to filter out high-frequency electromagnetic noise above 240kHz, ensuring a smooth and stable signal. The linear regulator provides a stable low-noise voltage.

[0009] Preferably, the fault monitoring module includes a fault detector, which has a built-in fixed threshold fault detection unit and an adjustable threshold fault detection unit. The Flag_F uses a built-in fixed fault threshold, requiring no additional components, and achieves a fast protection response of ≤2μs, suitable for severe short-circuit fault detection. The Flag_S allows users to set the fault threshold themselves through an external voltage divider resistor and has a current pulse shielding function.

[0010] Preferably, the communication output module includes a signal communicator, which supports both analog voltage output and digital communication output modes. The analog voltage output can provide static voltage outputs of 0.1Vcc and 0.5Vcc, and the output signal has an ideal ratio to the measured current value. The digital communication output includes connecting wires and a transmission interface, which uploads the measured current data and fault information to the vehicle controller in real time.

[0011] Preferably, a magnetic isolation base is fixedly installed on the outside of the magnetic sensor, and the side of the magnetic isolation base away from the magnetic sensor is fixedly connected to the inside of the encapsulation shell. The magnetic isolation base adopts a coreless design and, combined with the differential measurement principle, has the ability to suppress stray magnetic fields.

[0012] Preferably, the encapsulated housing also contains a temperature compensation module, which includes a temperature compensator. The temperature compensator collects the ambient temperature and calls a pre-stored temperature drift compensation table to correct measurement errors caused by temperature changes.

[0013] Preferably, the encapsulation shell has a ceramic insulating layer inside, and the surface of the encapsulation shell is coated with a waterproof and dustproof coating.

[0014] Preferably, five mounting plates are fixedly installed inside the encapsulation housing. The linear regulator, magnetic sensor, low-pass filter, low-noise amplifier and ADC converter are respectively installed on one side of the five mounting plates. A top sealing plate is fixedly installed on the top of the mounting plates. The signal communicator is fixedly installed on the top of the top sealing plate. The temperature compensator is fixedly installed on the bottom of the magnetic isolation base.

[0015] Compared with the prior art, the beneficial effects of the present invention are: the signal conditioning stage amplifies the signal twice through a low-noise amplifier and filters out high-frequency electromagnetic noise through an FIR filtering algorithm, and provides a stable low-noise power supply with a linear regulator, effectively avoiding the effects of signal distortion and power supply fluctuations; each functional module is independently installed on a dedicated mounting plate, and the integrated packaging design reduces external interference, ensuring that the device continues to operate stably in the harsh working environment of new energy vehicles; The device can be quickly connected in series to various high-voltage current circuits of new energy vehicles through a series connector. The communication output module supports both analog voltage and digital communication modes. Digital communication can be directly connected to the vehicle controller through connecting wires and transmission interfaces, adapting to the usage requirements of different scenarios. The integrated design reduces peripheral components, simplifies the installation process, and facilitates batch application. The fault monitoring system adopts a dual-threshold detection design. The fixed threshold (Flag_F) can achieve a fast protection response of ≤2μs to deal with severe short-circuit faults in a timely manner. The adjustable threshold (Flag_S) supports user customization and has a pulse shielding function to avoid false alarms. At the same time, real-time fault monitoring and fault information uploading provide multiple safety guarantees for the vehicle power system and reduce the risk of faults. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the three-dimensional appearance structure of the present invention.

[0017] Figure 2 This is a schematic diagram of the structure from another perspective, looking up from below, of the present invention.

[0018] Figure 3 This is a schematic diagram of the three-dimensional structure of the present invention without the outer packaging shell.

[0019] Figure 4 This is a three-dimensional structural diagram of the present invention with the packaging shell removed from another perspective.

[0020] Figure 5 This is a partial three-dimensional structural diagram of the present invention.

[0021] Figure 6 This is a schematic diagram of the operation flow of the present invention.

[0022] In the diagram: 1. Encapsulation housing; 2. Built-in current conductor; 3. Series connector; 4. Connecting conductor; 5. Transmission interface; 6. Mounting plate; 7. Fault detector; 8. Linear regulator; 9. Magnetic sensor; 10. Low-pass filter; 11. Low-noise amplifier; 12. ADC converter; 13. Magnetic shield; 14. Temperature compensator; 15. Mounting cylinder; 16. Signal communicator; 17. Top sealing plate. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Please see Figures 1-6This invention provides a technical solution: an automotive-grade isolated current sensing device, comprising a housing 1, and an internal current conductor 2, an isolation detection module, a signal conditioning module, a fault monitoring module, and a communication output module installed inside the housing 1. The internal current conductor, isolation detection module, signal conditioning module, fault monitoring module, and communication output module are integrated within the housing 1, achieving a unified design. Both ends of the internal current conductor 2 are fixedly connected to series connectors 3. Mounting cylinders 15 are fixedly installed at the top and bottom of the housing 1, and the internal current conductor 2 is fixedly installed inside the mounting cylinders 15. The internal current conductor 2 is made of high-conductivity copper, and its impedance is as low as 0.24mΩ, capable of carrying DC and AC currents from 0A to 150A. The isolation detection module includes a magnetic sensor 9 and an ADC converter 12. The magnetic sensor 9 is located outside the internal current conductor 2 and, based on the magnetic effect of the current, senses the magnetic field generated around the internal current conductor 2 that is proportional to the current and converts it into a weak voltage signal. The ADC converter 12... A 16-bit high-precision analog-to-digital converter is used to read and amplify weak voltage signals to ensure measurement accuracy. The signal conditioning module includes a low-noise amplifier 11, a low-pass filter 10, and a linear regulator 8. The low-noise amplifier 11 amplifies the signal converted by the ADC converter 12. The low-pass filter 10 uses an FIR filtering algorithm to filter out high-frequency electromagnetic noise above 240kHz, ensuring a smooth and stable signal. The linear regulator 8 provides a stable low-noise voltage. The fault monitoring module includes a fault detector 7, which has a built-in fixed-threshold fault detection unit and an adjustable-threshold fault detection unit. Flag_F uses a built-in fixed fault threshold, requiring no additional components, and achieves a fast protection response of ≤2μs, suitable for severe short-circuit fault detection. Flag_S allows users to set the fault threshold through external voltage divider resistors and has a current pulse shielding function. The communication output module includes a signal communicator 16, which supports both analog voltage output and digital communication output modes. The analog voltage output can provide 0.1Vcc and 0.The static voltage output is 5Vcc, and the output signal has an ideal ratio to the measured current value. The digital communication output includes connecting wire 4 and transmission interface 5, which uploads the measured current data and fault information to the vehicle controller in real time. A magnetic shielding base 13 is fixedly mounted on the outside of the magnetic sensor 9. The side of the magnetic shielding base 13 away from the magnetic sensor 9 is fixedly connected to the inside of the encapsulation shell 1. The magnetic shielding base 13 adopts a coreless design and, combined with the differential measurement principle, has stray magnetic field suppression capability. Five mounting plates 6 are fixedly mounted inside the encapsulation shell 1. A linear regulator 8, a magnetic sensor 9, a low-pass filter 10, a low-noise amplifier 11, and an ADC converter 12 are respectively mounted on one side of the five mounting plates 6. A top sealing plate 17 is fixedly mounted on the top of the mounting plate 6. A signal communicator 16 is fixedly mounted on the top of the top sealing plate 17. A temperature compensator 14 is fixedly mounted on the bottom of the magnetic shielding base 13. A temperature compensation module is also encapsulated inside the encapsulation shell 1.

[0025] The working principle of the above technical solution is as follows: The device is connected in series to the high-voltage current circuit of the new energy vehicle through the series connectors 3 at both ends of the built-in current conductor 2. The measured current flows into the built-in current conductor 2 through the series connectors 3. The built-in current conductor 2 is fixedly installed inside the mounting cylinder 15 at the top and bottom of the shell enclosure 1. It is made of high-conductivity copper material to carry DC and AC currents with low impedance, so as to achieve stable current transmission. After the built-in current conductor 2 carries current, a magnetic field proportional to the magnitude of the current is generated around it based on the magnetic effect of the current. The magnetic sensor 9 located outside the built-in current conductor 2 senses the magnetic field and converts the magnetic field signal into a weak voltage signal. The magnetic isolation base 13 adopts a coreless design and, combined with the differential measurement principle, effectively suppresses stray magnetic fields. To prevent field interference and ensure the accuracy of magnetic field sensing, the magnetic isolation base 13 is fixedly connected to the inner side of the package shell 1 on the side away from the magnetic sensor 9, ensuring the installation stability of the magnetic sensor 9. The ADC converter 12 reads the weak voltage signal output by the magnetic sensor 9 and amplifies the signal to ensure measurement accuracy, laying the foundation for subsequent signal conditioning. The ADC converter 12 is mounted on one of the mounting plates 6 inside the package shell 1, which provides stable mounting support. The temperature compensator 14 in the temperature compensation module collects the ambient temperature inside the package shell 1 in real time and corrects the temperature drift of the signal processed by the ADC converter 12, eliminating measurement errors caused by temperature changes and further improving measurement accuracy. The signal conditioning module... Upon startup, the low-noise amplifier 11, mounted on the corresponding mounting plate 6, amplifies the signal amplified by the ADC converter 12 a second time, enhancing signal strength. Subsequently, the low-pass filter 10 employs an FIR filtering algorithm to filter out high-frequency electromagnetic noise, ensuring a smooth and stable signal. Simultaneously, the linear regulator 8 provides a stable low-noise voltage for the entire device, preventing power supply fluctuations from affecting signal processing and measurement accuracy. The fault detector 7 in the fault monitoring module receives the conditioned current signal in real time and performs fault judgment through its built-in fixed threshold fault detection unit Flag_F and adjustable threshold fault detection unit Flag_S. If the current exceeds the built-in fixed fault threshold Flag_F, no additional components are required, achieving a fault ≤2μs. The system provides rapid protection response to severe short-circuit faults. If the current exceeds the fault threshold Flag_S set by the user through the external voltage divider resistor, a corresponding response is triggered. The current pulse shielding function of Flag_S can avoid false alarms caused by interference signals. The signal communicator 16 in the communication output module receives the conditioned and fault-detected signal and outputs the signal using one of two output modes. If the analog voltage output mode is used, it can provide the corresponding static voltage output, and the output signal is ideally proportional to the measured current value. If the digital communication output mode is used, the accurate measured current data and fault information generated by fault monitoring are uploaded to the vehicle controller in real time through the connecting wire 4 and the transmission interface 5, providing data support for vehicle control.

[0026] In another implementation scheme, such as Figures 1-6 As shown, the temperature compensation module includes a temperature compensator 14. The temperature compensator 14 collects the ambient temperature and calls the pre-stored temperature drift compensation table to correct the measurement error caused by temperature changes.

[0027] The temperature compensator 14 is fixedly installed at the bottom of the magnetic isolation base 13 and works in conjunction with the isolation detection module. It is specifically designed to eliminate the influence of temperature changes on measurement accuracy. During operation, the temperature compensator 14 collects the ambient temperature inside the package shell 1 in real time, accurately captures temperature fluctuations within the automotive-grade operating temperature range of -40℃ to 125℃, and synchronously calls the internally stored temperature drift compensation table. Based on the collected real-time temperature, it can automatically match the corresponding compensation parameters to accurately correct the temperature drift of the signal processed by the ADC converter 12. This effectively offsets the sensitivity shift of the magnetic sensor 9 and the measurement deviation of the ADC converter 12 caused by temperature changes, completely eliminates the measurement error caused by temperature factors, further improves the measurement accuracy of the device in a wide temperature environment, and ensures that the device can still stably output accurate current measurement data under the extreme operating temperature of new energy vehicles.

[0028] In another implementation scheme, such as Figures 1-6 As shown, the encapsulation shell 1 has a ceramic insulating layer inside, and the surface of the encapsulation shell 1 is coated with a waterproof and dustproof coating.

[0029] The device can be protected by the encapsulation shell 1.

[0030] Working Principle: The device is connected in series to the high-voltage current circuit of a new energy vehicle through the series connectors 3 at both ends of the built-in current conductor 2. The current to be measured flows into the built-in current conductor 2 through the series connectors 3. The built-in current conductor 2 is fixedly installed inside the mounting cylinders 15 at the top and bottom of the shell enclosure 1. It is made of high-conductivity copper material to carry DC and AC currents with low impedance, achieving stable current transmission. After the built-in current conductor 2 carries current, a magnetic field proportional to the magnitude of the current is generated around it based on the magnetic effect of the current. The magnetic sensor 9 located outside the built-in current conductor 2 senses the magnetic field and converts the magnetic field signal into a weak voltage signal. The magnetic isolation base 13 adopts a coreless design and, combined with the differential measurement principle, effectively suppresses stray magnetic field interference to ensure magnetic field sensing. To ensure accuracy, the side of the magnetic isolation base 13 furthest from the magnetic sensor 9 is fixedly connected to the inside of the package housing 1, ensuring the installation stability of the magnetic sensor 9. The ADC converter 12 reads the weak voltage signal output by the magnetic sensor 9 and amplifies the signal to ensure measurement accuracy, laying the foundation for subsequent signal conditioning. The ADC converter 12 is installed on one of the mounting plates 6 inside the package housing 1, which provides stable installation support. The temperature compensator 14 in the temperature compensation module collects the ambient temperature inside the package housing 1 in real time and corrects the temperature drift of the signal processed by the ADC converter 12, eliminating measurement errors caused by temperature changes and further improving measurement accuracy. The signal conditioning module then starts working and is installed on the corresponding mounting plate. The low-noise amplifier 11 on board 6 amplifies the signal amplified by the ADC converter 12 a second time to enhance signal strength. Subsequently, the low-pass filter 10 uses an FIR filtering algorithm to filter out high-frequency electromagnetic noise, ensuring a smooth and stable signal. Simultaneously, the linear regulator 8 provides a stable low-noise voltage for the entire device, preventing power supply fluctuations from affecting signal processing and measurement accuracy. The fault detector 7 in the fault monitoring module receives the conditioned current signal in real time and performs fault judgment through its built-in fixed-threshold fault detection unit Flag_F and adjustable-threshold fault detection unit Flag_S. If the current exceeds the built-in fixed fault threshold Flag_F, an immediate and rapid protection response is provided without additional components to handle severe short-circuit faults. If the current exceeds the fault threshold Flag_S set by the user through the external voltage divider resistor, a corresponding response is triggered. The current pulse shielding function of Flag_S can prevent false alarms caused by interference signals. The signal communicator 16 in the communication output module receives the conditioned and fault-detected signal and outputs the signal using one of two modes. If the analog voltage output mode is used, a corresponding static voltage output can be provided, and the output signal has an ideal ratio to the measured current value. If the digital communication output mode is used, the accurate measured current data and fault information generated by fault monitoring are uploaded to the vehicle controller in real time through the connecting wire 4 and the transmission interface 5, providing data support for vehicle control. The temperature compensator 14 is fixedly installed at the bottom of the magnetic shielding base 13.Working in conjunction with the isolation detection module, this device is specifically designed to eliminate the impact of temperature changes on measurement accuracy. During operation, the temperature compensator 14 collects the ambient temperature inside the package 1 in real time, accurately capturing temperature fluctuations within the automotive-grade operating temperature range of -40℃ to 125℃. Simultaneously, it calls upon the internally stored temperature drift compensation table, automatically matching the corresponding compensation parameters based on the collected real-time temperature. This precisely corrects the temperature drift of the signal processed by the ADC converter 12, effectively offsetting issues such as sensitivity shift of the magnetic sensor 9 and measurement deviation of the ADC converter 12 caused by temperature changes. This completely eliminates measurement errors caused by temperature factors, further improving the measurement accuracy of the device in a wide temperature range and ensuring that the device can still stably output accurate current measurement data even under the extreme operating temperatures of new energy vehicles.

[0031] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An automotive-grade isolated current sensing device, comprising a housing (1), and internally mounted current conductors (2), an isolation detection module, a signal conditioning module, a fault monitoring module, and a communication output module, characterized in that: The built-in current conductor, isolation detection module, signal conditioning module, fault monitoring module and communication output module are integrated in the package shell (1) to achieve an integrated design. Both ends of the built-in current conductor (2) are fixedly connected to series connectors (3).

2. The automotive-grade isolated current sensing device according to claim 1, characterized in that: The top and bottom of the encapsulation shell (1) are fixedly installed with mounting cylinders (15), and the built-in current conductor (2) is fixedly installed inside the mounting cylinder (15). The built-in current conductor (2) is made of copper with high conductivity. The conductor impedance of the built-in current conductor (2) is as low as 0.24mΩ, and it can carry DC and AC currents of 0A to 150A.

3. The automotive-grade isolated current sensing device according to claim 2, characterized in that: The isolation detection module includes a magnetic sensor (9) and an ADC converter (12). The magnetic sensor (9) is located outside the built-in current conductor (2). Based on the magnetic effect of the current, it senses the magnetic field generated around the built-in current conductor (2) that is proportional to the current and converts it into a weak voltage signal. The ADC converter (12) is a 16-bit high-precision analog-to-digital converter that reads and amplifies the weak voltage signal to ensure measurement accuracy.

4. The automotive-grade isolated current sensing device according to claim 3, characterized in that: The signal conditioning module includes a low-noise amplifier (11), a low-pass filter (10), and a linear regulator (8). The low-noise amplifier (11) amplifies the signal converted by the ADC converter (12) a second time. The low-pass filter (10) uses the FIR filtering algorithm to filter out high-frequency electromagnetic noise above 240kHz, ensuring that the signal is smooth and stable. The linear regulator (8) provides a stable low-noise voltage.

5. The automotive-grade isolated current sensing device according to claim 4, characterized in that: The fault monitoring module includes a fault detector (7), which has a built-in fixed threshold fault detection unit and an adjustable threshold fault detection unit. The Flag_F adopts a built-in fixed fault threshold, requiring no additional components, and achieves a fast protection response of ≤2μs, suitable for severe short-circuit fault detection. The Flag_S allows users to set the fault threshold themselves through external voltage divider resistors and has a current pulse shielding function.

6. The automotive-grade isolated current sensing device according to claim 5, characterized in that: The communication output module includes a signal communicator (16), which supports two modes: analog voltage output and digital communication output. The analog voltage output can provide static voltage outputs of 0.1Vcc and 0.5Vcc, and the output signal has an ideal ratio with the measured current value. The digital communication output includes a connecting wire (4) and a transmission interface (5), which uploads the measured current data and fault information to the vehicle controller in real time.

7. The automotive-grade isolated current sensing device according to claim 6, characterized in that: A magnetic isolation base (13) is fixedly installed on the outside of the magnetic sensor (9). The side of the magnetic isolation base (13) away from the magnetic sensor (9) is fixedly connected to the inside of the encapsulation shell (1). The magnetic isolation base (13) adopts a coreless design and, combined with the differential measurement principle, has the ability to suppress stray magnetic fields.

8. The automotive-grade isolated current sensing device according to claim 7, characterized in that: The encapsulation shell (1) also encapsulates and installs a temperature compensation module, which includes a temperature compensator (14). The temperature compensator (14) collects the ambient temperature and calls the pre-stored temperature drift compensation table to correct the measurement error caused by temperature changes.

9. The automotive-grade isolated current sensing device according to claim 8, characterized in that: The encapsulation shell (1) has a ceramic insulating layer inside, and the surface of the encapsulation shell (1) is coated with a waterproof and dustproof coating.

10. The automotive-grade isolated current sensing device according to claim 9, characterized in that: Five mounting plates (6) are fixedly installed inside the encapsulation shell (1). The linear regulator (8), magnetic sensor (9), low-pass filter (10), low-noise amplifier (11) and ADC converter (12) are respectively installed on one side of the five mounting plates (6). A top sealing plate (17) is fixedly installed on the top of the mounting plate (6). The signal communicator (16) is fixedly installed on the top of the top sealing plate (17). The temperature compensator (14) is fixedly installed on the bottom of the magnetic isolation base (13).

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