Dynamic range current measurement module

Abstract

The utility model discloses a dynamic range current measurement module which comprises a shunt resistance switching unit, a 24-bit precision ADC unit, an MCU processing unit, a crystal oscillator unit, an isolation unit, a 485 interface unit and a power supply unit. The shunt resistor switching unit is used for dynamically selecting shunt resistors with different resistance values according to the magnitude of the current to be measured so as to realize current measurement in a range of 10 uA to 10 A, the shunt resistor of 1 ohm is used in a range of 10 uA to 20 mA, and the shunt resistor of 10 m ohm is used in a range of 20 mA to 10 A; the 24-bit precision ADC unit is used for collecting the analog current signal passing through the shunt resistor and converting the analog current signal into a digital signal; according to the utility model, the dynamic range current measuring module is provided, so that when the current measuring range span is large, the measuring range can be automatically switched, and a tester does not need to replace testing equipment with different measuring ranges; measurement data can be continuously acquired; the electrical isolation loop allows the measurement point to be arranged at any position: a power supply or return wire, measuring part or all of the current.

Description

Technical Field

[0001] The utility model relates to the technical field of current measurement, in particular to a dynamic range current measurement module. Background Art

[0002] Currently, continuous testing of electric vehicles to analyze the complete power cycle, including micro-leakage current in sleep mode, surge and impact during startup, high power consumption during operation, and the process of returning to sleep mode, requires a reliable, high-precision, and large-range current measurement method. This test must be non-reactive, that is, the measurement equipment should not have any effect on the physical quantity to be measured during the entire measurement cycle, and provide sufficient measurement accuracy throughout the test process.

[0003] The conventional approach is to use a shunt to accurately sample the on-line current and then use an ADC to process the signal.

[0004] Deficiencies in existing technology: To ensure measurement accuracy, circuit design is very complex, the equipment is large and expensive, and ordinary current measuring devices have poor current testing capabilities, and their test accuracy cannot meet high-precision requirements, making it impossible to achieve accurate and effective current measurement.

[0005] Therefore, in order to solve the shortcomings of the above problems, a dynamic range current measurement module is proposed. Summary of the Invention

[0006] The utility model overcomes the deficiencies of the prior art and provides a dynamic range current measurement module.

[0007] To achieve the above object, the technical solution adopted by the utility model is: a dynamic range current measurement module, including: a shunt resistor switching unit, a 24-bit precision ADC unit, an MCU processing unit, a crystal oscillator unit, an isolation unit, a 485 interface unit and a power supply unit;

[0008] The shunt resistor switching unit is electrically connected to the 24-bit precision ADC unit, the 24-bit precision ADC unit is electrically connected to the isolation unit, the isolation unit is electrically connected to the MCU processing unit, the crystal oscillator unit is electrically connected to the MCU processing unit, the 485 interface unit is electrically connected to the MCU processing unit, and the power supply unit is electrically connected to the MCU processing unit;

[0009] The shunt resistor switching unit is used to dynamically select shunt resistors of different resistance values ​​according to the size of the current to be measured to achieve current measurement in the range of 10uA to 10A. The shunt resistor uses a 1Ω shunt resistor in the range of 10uA to 20mA, and a 10mΩ shunt resistor in the range of 20mA-10A.

[0010] In a preferred embodiment of the present invention, the 24-bit precision ADC unit is used to collect the analog current signal after the shunt resistor and convert it into a digital signal. The 24-bit precision ADC unit can collect the weak analog current signal after the shunt resistor and accurately convert it into a digital signal for subsequent processing. Its 24-bit high resolution ensures the accuracy of the measurement results, capturing details even with small current changes.

[0011] In a preferred embodiment of this utility model, the MCU processing unit is used to receive and process the digital signal output by the 24-bit precision ADC unit, performing filtering, amplification, and calibration. This MCU processing unit utilizes ST's F1 series chips. By adopting ST's F1 series chips, the MCU processing unit possesses powerful data processing capabilities and stability, enabling efficient processing of large amounts of data and ensuring real-time and accurate measurement results. The filtering function removes noise and outliers, improving data reliability; the amplification function enhances signal strength, making it easier to analyze and process; and the calibration function ensures the accuracy and consistency of measurement results.

[0012] In a preferred embodiment of the present invention, the crystal oscillator unit provides a stable clock signal for the MCU processing unit. The crystal oscillator unit employs an 8MHz quartz crystal oscillator. The 8MHz quartz crystal oscillator provides a highly precise clock signal, ensuring that the MCU processing unit can process and output data at predetermined intervals. This stable clock signal not only improves the system's real-time performance but also ensures the accuracy and repeatability of measurement results.

[0013] In a preferred embodiment of the present invention, the isolation unit is used to isolate the measurement part from the control part in the 24-bit precision ADC unit to prevent the control part from interfering with the measurement part. This not only improves the anti-interference ability of the system, but also ensures the accuracy and stability of the measurement results. Especially in complex electromagnetic environments, the role of the isolation unit is more prominent, and it can protect the measurement system from external interference.

[0014] In a preferred embodiment of the present invention, the 485 interface unit is used to transmit the data processed by the MCU to the external device through the 485 bus.

[0015] In a preferred embodiment of the present invention, the 485 interface unit adopts a Siproin low-power RS485 transceiver.

[0016] In a preferred embodiment of the present invention, the power supply unit includes a voltage stabilizing circuit for providing a stable operating voltage for the entire module. The stable operating voltage provided by the power supply unit includes at least a +5V power supply and GND.

[0017] In a preferred embodiment of the present invention, a fast switch is provided in the shunt resistor switching unit.

[0018] In a preferred embodiment of the present invention, the fast switch is used to dynamically switch to a high-resistance shunt resistor for measurement when the current to be measured is lower than a preset threshold.

[0019] The present invention solves the defects in the background technology and has the following beneficial effects:

[0020] (1) The present invention provides a dynamic range current measurement module, which can automatically switch the range when the current measurement range spans a large range, and the tester does not need to change the test equipment of different ranges; the measurement data can be collected continuously; the electrical isolation circuit allows the measurement point to be arranged at any position: power supply or return wire (high voltage side / low voltage side), measuring part or all of the current, speeding up the test progress. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention is further described below with reference to the accompanying drawings and embodiments;

[0022] Figure 1 It is a terminal structure diagram of a preferred embodiment of the present utility model.

[0023] In the figure: 1. Shunt resistor switching unit; 2. 24-bit precision ADC unit; 3. Isolation unit; 4. MCU processing unit; 5. Crystal oscillator unit; 6. 485 interface unit; 7. Power supply unit. DETAILED DESCRIPTION

[0024] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. These drawings are simplified schematic diagrams that only illustrate the basic structure of the present invention in a schematic manner, and therefore only show components related to the present invention.

[0025] like Figure 1 As shown, the dynamic range current measurement module, the utility model overcomes the shortcomings of the prior art and provides a dynamic range current measurement module.

[0026] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is as follows: a dynamic range current measurement module, comprising: a shunt resistor switching unit 1, a 24-bit precision ADC unit 2, an MCU processing unit 4, a crystal oscillator unit 5, an isolation unit 3, a 485 interface unit 6 and a power supply unit 7;

[0027] The shunt resistor switching unit 1 is electrically connected to the 24-bit precision ADC unit 2, the 24-bit precision ADC unit 2 is electrically connected to the isolation unit 3, the isolation unit 3 is electrically connected to the MCU processing unit 4, the crystal oscillator unit 5 is electrically connected to the MCU processing unit 4, the 485 interface unit 6 is electrically connected to the MCU processing unit 4, and the power supply unit 7 is electrically connected to the MCU processing unit 4;

[0028] A shunt resistor switching unit 1 is used to dynamically select shunt resistors of different resistance values ​​according to the magnitude of the current to be measured, so as to achieve current measurement in the range of 10uA to 10A. A 1Ω shunt resistor is used in the shunt resistor range of 10uA to 20mA, and a 10mΩ shunt resistor is used in the shunt resistor range of 20mA to 10A. A fast switch is provided in the shunt resistor switching unit 1. The fast switch is used to dynamically switch to a high-resistance shunt resistor for measurement when the current to be measured is lower than a preset threshold;

[0029] 24-bit precision ADC unit 2, used to collect the analog current signal after the shunt resistor and convert it into a digital signal;

[0030] Isolation unit 3 is used to isolate the measurement part of the 24-bit precision ADC unit 2 from the control part to prevent the control part from interfering with the measurement part. This not only improves the system's anti-interference ability but also ensures the accuracy and stability of the measurement results. Especially in complex electromagnetic environments, the role of isolation unit 3 is more prominent, and it can protect the measurement system from external interference.

[0031] The MCU processing unit 4 is used to receive and process the digital signal output by the 24-bit precision ADC unit 2, and perform screening, amplification, and calibration. The MCU processing unit 4 uses ST's F1 series chips. By adopting ST's F1 series chips, the MCU processing unit 4 has powerful data processing capabilities and stability, and can efficiently process large amounts of data, ensuring the real-time and accuracy of the measurement results. The screening function can remove noise and outliers, improving the reliability of the data; the amplification function can enhance the strength of the signal, making it easier for subsequent analysis and processing; the calibration function ensures the accuracy and consistency of the measurement results. The crystal oscillator unit 5 provides a stable clock signal for the MCU processing unit 4. The crystal oscillator unit 5 uses an 8MHz quartz crystal oscillator. The use of an 8MHz quartz crystal oscillator can provide a high-precision clock signal, ensuring that the MCU processing unit 4 can process and output data at predetermined time intervals. The stable clock signal not only improves the real-time performance of the system, but also ensures the accuracy and repeatability of the measurement results.

[0032] The 485 interface unit 6 is used to transmit the data processed by the MCU to the external device through the 485 bus. The 485 interface unit 6 adopts the Siproin low-power RS485 transceiver.

[0033] The power supply unit 7 includes a voltage stabilizing circuit for providing a stable operating voltage for the entire module. The stable operating voltage provided by the power supply unit 7 includes at least a +5V power supply and GND.

[0034] It should be noted that first, a low-resistance 10mΩ shunt resistor is used in the shunt resistor switching unit 1, which is always in an active state to measure the maximum current. Then, a high-resistance 1Ω shunt resistor is connected in series to measure the minimum current. When the operating current to be measured is lower than the 20mA threshold, the 1Ω shunt resistor is dynamically switched on and off through a fast switch. The voltage values ​​of the two shunt resistors are measured using a 24-bit ADC through the 24-bit precision ADC unit 2, and then filtered, amplified, and calibrated by the MCU processing unit 4. The test data is output through the 485 bus in the 485 interface unit 6 at a sampling rate of 1Hz to 1kHz. The output variables include the maximum, minimum, and average values ​​of the selected data, and these output values ​​are derived from the internal data of the ADC.

[0035] Working Principle: The current measurement power interface is connected to the +5V power supply and GND, and the communication interface is connected to the 485 interface unit 6; the input and output of the current measurement are connected in series to the circuit to be measured; after the wiring is completed and the power is turned on, the 24-bit precision ADC unit 2 will automatically collect circuit data and send the data to the MCU processing unit 4; the MCU processing unit 4 processes the data from the 24-bit precision ADC unit 2 and sends it to the 485 bus through the 485 transceiver in the 485 interface unit 6. The data is then analyzed externally by the host computer.

[0036] The above description is based on the ideal embodiment of the present invention. Based on the above description, relevant personnel can make various changes and modifications without departing from the technical scope of the present invention. The technical scope of the present invention is not limited to the content of the specification, but must be determined according to the scope of the claims.

Claims

1. Dynamic range current measurement module, including: A shunt resistor switching unit (1), a 24-bit precision ADC unit (2), an MCU processing unit (4), a crystal oscillator unit (5), an isolation unit (3), a 485 interface unit (6) and a power supply unit (7), characterized in that: The shunt resistor switching unit (1) is electrically connected to the 24-bit precision ADC unit (2), the 24-bit precision ADC unit (2) is electrically connected to the isolation unit (3), the isolation unit (3) is electrically connected to the MCU processing unit (4), the crystal oscillator unit (5) is electrically connected to the MCU processing unit (4), the 485 interface unit (6) is electrically connected to the MCU processing unit (4), and the power supply unit (7) is electrically connected to the MCU processing unit (4); The shunt resistor switching unit (1) is used to dynamically select shunt resistors of different resistance values ​​according to the magnitude of the current to be measured, so as to achieve current measurement in the range of 10uA to 10A. The shunt resistor uses a 1Ω shunt resistor in the range of 10uA to 20mA, and uses a 10mΩ shunt resistor in the range of 20mA to 10A.

2. The dynamic range current measurement module according to claim 1, wherein: The 24-bit precision ADC unit (2) is used to collect the analog current signal after passing through the shunt resistor and convert it into a digital signal.

3. The dynamic range current measurement module according to claim 1, wherein: The MCU processing unit (4) is used to receive and process the digital signal output by the 24-bit precision ADC unit (2), and perform screening, amplification and calibration.

4. The dynamic range current measurement module according to claim 1, wherein: The MCU processing unit (4) adopts ST's F1 series chip, and the crystal oscillator unit (5) provides a stable clock signal for the MCU processing unit (4). The crystal oscillator unit (5) adopts an 8MHz quartz crystal oscillator.

5. The dynamic range current measurement module according to claim 1, wherein: The isolation unit (3) is used to isolate the measuring part from the control part, thereby preventing the control part from interfering with the measuring part.

6. The dynamic range current measurement module according to claim 1, characterized in that: The 485 interface unit (6) is used to transmit the data processed by the MCU to an external device through the 485 interface unit (6).

7. The dynamic range current measurement module according to claim 6, characterized in that: The 485 interface unit (6) adopts a Siproin low-power RS485 transceiver.

8. The dynamic range current measurement module according to claim 1, characterized in that: The power supply unit (7) contains a voltage stabilizing circuit for providing a stable operating voltage for the entire module. The stable operating voltage provided by the power supply unit (7) includes at least a +5V power supply and GND.

9. The dynamic range current measurement module according to claim 1, characterized in that: A fast switch is provided in the shunt resistor switching unit (1).

10. The dynamic range current measurement module according to claim 9, characterized in that: The fast switch is used to dynamically switch to a high-resistance shunt resistor for measurement when the current to be measured is lower than a preset threshold.

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