Device and method for detecting cable current

Abstract

The invention discloses a device and method for detecting cable current, and relates to the field of current detection, and the device comprises a switching circuit module, a TMR current measurement module, a voltage detection module, a power management module, an MCU control module and a communication module. The switching circuit module is used for receiving a current measurement control signal of the MCU control module and controlling the starting and stopping of the TMR current measurement module according to the current measurement control signal; the TMR current measurement module is used for detecting cable current information when being started; compared with the prior art, the device has the beneficial effects that the TMR sensor is adopted to collect the current of the cable, power failure operation is not needed in mounting and dismounting, and operation and maintenance are convenient; compared with a traditional voltage / current transformer, the size is small; the operational amplifier circuit and the A / D module are arranged to complete amplification and analog-to-digital conversion processing, intelligent control of the MCU control module is facilitated, remote communication is facilitated by arranging the wireless communication module, and intelligence is high.

Description

Technical Field

[0001] This invention relates to the field of current detection, specifically to a device and method for detecting cable current. Background Technology

[0002] Current transformers and voltage transformers (PT / CT), also known as instrument converters, can be used with measuring instruments to measure the voltage, current, and electrical energy of a line. Traditional voltage / current transformers remain the basic means for power systems to collect electrical quantities from cables, but they cannot meet the major demands of digital grid construction, such as flexibility, efficiency, digital empowerment, and ubiquitous Internet of Things.

[0003] The problems are prominent: (1) It requires intrusive measurement through primary system wiring, and installation and removal require power outages, and the maintenance workload is large, and it does not have the ability to be used immediately; (2) Traditional voltage / current transformers are large in size, usually reaching the meter level, which is inconvenient for transportation; (3) The range and frequency response are not good enough, and they do not have digital output function, and the level of intelligence is low.

[0004] Therefore, the need for upgrading and replacement is urgent, and a new cable current detection device is required. Summary of the Invention

[0005] The purpose of this invention is to provide an apparatus and method for detecting cable current, in order to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A device for detecting cable current includes a TMR current measurement module, a current measurement calibration module, a temperature measurement module, a temperature measurement calibration module, and an MCU control module.

[0008] The TMR current measurement module is used to detect cable current and obtain the initial signal of cable current.

[0009] The current measurement and calibration module is used to calibrate the initial signal of the cable current and generate a first calibration signal;

[0010] The temperature measurement module is used to measure the ambient temperature and obtain a temperature signal;

[0011] The temperature measurement and calibration module is used to calibrate the temperature signal and generate a second calibration signal;

[0012] The MCU control module is used to receive and determine the corrected cable current based on the initial cable current signal, the first calibration signal, the temperature signal, and the second calibration signal.

[0013] As a further embodiment of the present invention: the TMR current measurement module includes: a switching circuit, a TMR current sensing unit, a first operational amplifier circuit unit, a second operational amplifier circuit unit, and a first A / D conversion unit; the switching circuit is used to control the activation and deactivation of the TMR current measurement module according to the current measurement control signal from the MCU control module; the TMR current sensing unit is used to sense the cable current and output a first analog voltage signal related to the cable current; the first operational amplifier circuit unit and the second operational amplifier circuit unit are connected in series between the TMR current sensing unit and the first A / D conversion unit to amplify the first analog voltage signal; the first A / D conversion unit is used to convert the amplified first analog voltage signal into a first digital voltage signal as the initial signal of the cable current.

[0014] As a further embodiment of the present invention: the TMR current sensing unit includes TMR sensor U1, TMR sensor U2, TMR sensor U3 and an accumulator; the TMR sensor U1, TMR sensor U2 and TMR sensor U3 are respectively used to measure the current of the same cable; the power supply terminals of the TMR sensor U1, TMR sensor U2 and TMR sensor U3 are all connected to the source of MOS transistor V1 in the switching circuit module; the accumulator is respectively connected to the output terminals of the TMR sensor U1, TMR sensor U2 and TMR sensor U3, and is used to accumulate the current sensing signals output from the TMR sensor U1, TMR sensor U2 and TMR sensor U3, and output the first analog voltage signal related to the cable current.

[0015] As a further embodiment of the present invention: the first operational amplifier circuit unit includes resistor R4, resistor R5, and amplifier U4; the output terminal of the accumulator is connected to the non-inverting input of amplifier U4; the inverting input of amplifier U4 is connected to one end of resistor R4 and one end of resistor R5; the other end of resistor R4 is grounded; the other end of resistor R5 is connected to the output terminal of amplifier U4; the second operational amplifier circuit unit includes resistor R6, adjustable resistor RP1, and amplifier U5; the output terminal of amplifier U4 is connected to the non-inverting input of amplifier U5; the inverting input of amplifier U5 is connected to one end of resistor R6 and one end of adjustable resistor RP1; the other end of resistor R6 is grounded; the other end of adjustable resistor RP1 is connected to the output terminal of amplifier U5.

[0016] As a further aspect of the present invention: the elliptical array formed by TMR sensors U1, U2, and U3 and the position of the cable under test are subject to the following constraints:

[0017]

[0018] In the formula: kmax1 k max2 Here, represents the offset coefficient ranges for the long and short sides of the elliptical array, D is the cable diameter, R is the inner diameter of the circular array, and a is the cable inclination angle. max k is the maximum tilt angle of the cable. s Let k be the range of movement of the cable along the longer side of the ellipse. s The following equation is obtained by solving:

[0019]

[0020] Where x and y are the offset variables of the cable on the long and short sides of the ellipse, respectively.

[0021] As a further embodiment of the present invention: the device for detecting cable current further includes: a power management module and a voltage detection module; the power management module is used to provide power to the TMR current measurement module, the voltage detection module and the MCU control module, and to forward the voltage abnormality signal to the MCU control module; the voltage detection module is used to detect the abnormality of the cable voltage, and to feed back the voltage abnormality signal to the power management module when the cable voltage is abnormal.

[0022] As a further embodiment of the present invention: the power management module includes a resistor R7, a capacitor C2, and a diode D1; one end of the resistor R7 is connected to the power supply voltage VCC; the other end of the resistor R7 is connected to one end of the capacitor C2 and the negative terminal of the diode D1; the other end of the capacitor C2 is grounded; the positive terminal of the diode D1 is grounded; the voltage detection module includes a capacitor C3, a capacitor C4, a capacitor C5, a resistor R8, and a diode D2; one end of the capacitor C3 is connected to the first cable to collect voltage L1, one end of the capacitor C4 is connected to the second cable to collect voltage L2, one end of the capacitor C5 is connected to the third cable to collect voltage L3, the other end of the capacitor C3 is connected to the other end of the capacitor C4, the other end of the capacitor C5, and one end of the resistor R8, the other end of the resistor R8 is connected to the positive terminal of the diode D2, and the negative terminal of the diode D2 is connected to the power management module.

[0023] As a further embodiment of the present invention: the device for detecting cable current further includes: the temperature measurement module includes a temperature sensor, a second operational amplifier circuit unit and a second A / D conversion unit; the temperature sensor is used to output a second analog voltage signal related to temperature; the second operational amplifier circuit is used to amplify the second analog voltage signal; the second A / D conversion unit is used to convert the amplified second analog voltage signal into a second digital voltage signal, which is then sent to the MCU control module as a temperature sensing signal.

[0024] As a further aspect of the present invention, the modified cable current is determined by the following formula:

[0025] I cable =k1*I initial *(1+k2*(T-T0))

[0026] Among them, I cable For the corrected cable current, I initial K is the initial signal of the cable current, k1 is the first calibration coefficient indicated by the first calibration signal, k2 is the second calibration coefficient indicated by the second calibration signal, T is the device temperature measured by the temperature measurement module, and T0 is the reference temperature.

[0027] A method for detecting cable current employs the device for detecting cable current as described in this invention. The method includes the following steps:

[0028] The cable current is detected by the TMR current measurement module to obtain the initial signal of the cable current;

[0029] The initial signal of the cable current is calibrated by the current measurement and calibration module to generate a first calibration signal;

[0030] The ambient temperature is measured by the temperature measurement module to obtain a temperature signal;

[0031] The temperature signal is calibrated by the temperature measurement and calibration module to generate a second calibration signal;

[0032] The MCU control module receives and determines the corrected cable current based on the initial cable current signal, the first calibration signal, the temperature signal, and the second calibration signal.

[0033] Compared with the prior art, the beneficial effects of the present invention are:

[0034] 1. This invention uses a TMR sensor to collect cable current, and installation and removal do not require power outages, making operation and maintenance convenient; it is smaller in size than traditional voltage / current transformers; by setting up current measurement calibration module, temperature measurement module and temperature measurement calibration module, the accuracy of the device's measurement results can be further improved.

[0035] 2. By setting positional constraints on the elliptical array formed by TMR sensors U1, U2, and U3 and the cable under test, the measurement accuracy of the TMR current measurement module can be improved, thereby obtaining more accurate cable current detection results.

[0036] 3. By setting up operational amplifier circuits and A / D modules, amplification and analog-to-digital conversion are completed, which facilitates intelligent control by the MCU control module. The addition of a wireless communication module facilitates remote communication, resulting in a high degree of intelligence. Attached Figure Description

[0037] Figure 1 This is a schematic diagram of a device for detecting cable current according to the present invention.

[0038] Figure 2 This is a circuit diagram of the TMR current measurement module of the present invention.

[0039] Figure 3 Circuit diagram for supplying the reference voltage.

[0040] Figure 4 This is the circuit diagram for the voltage detection module. Figure 5 This is a schematic diagram showing the range of movement of the current-carrying cable within the circular array formed by TMR sensors U1, U2, and U3 when the current-carrying cable has an angle of inclination. Detailed Implementation

[0041] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0042] Please see Figure 1 The present invention provides a device for detecting cable current, comprising a TMR current measurement module, a current measurement calibration module, a temperature measurement module, a temperature measurement calibration module, and an MCU control module;

[0043] The TMR current measurement module is used to detect cable current and obtain the initial signal of cable current.

[0044] The current measurement and calibration module is used to calibrate the initial signal of the cable current and generate a first calibration signal;

[0045] The temperature measurement module is used to measure the ambient temperature and obtain a temperature signal;

[0046] The temperature measurement and calibration module is used to calibrate the temperature signal and generate a second calibration signal;

[0047] The MCU control module is used to receive and determine the corrected cable current based on the initial cable current signal, the first calibration signal, the temperature signal, and the second calibration signal.

[0048] This invention uses a TMR sensor to collect cable current, and installation and removal do not require power outages, making operation and maintenance convenient. It is smaller in size than traditional voltage / current transformers. By setting up current measurement calibration modules, temperature measurement modules, and temperature measurement calibration modules, the accuracy of the device's measurement results can be further improved.

[0049] In a specific embodiment: Please refer to Figure 1 The device for detecting cable current further includes a power management module and a voltage detection module. The power management module provides power to the TMR current measurement module, the voltage detection module, and the MCU control module, and forwards the voltage anomaly signal to the MCU control module. The voltage detection module detects cable voltage anomalies and, when a cable voltage anomaly occurs, feeds back a voltage anomaly signal to the power management module.

[0050] In a specific embodiment: Please refer to Figure 1 The device for detecting cable current also includes a wireless communication module. The MCU control module is connected to the wireless communication module via communication ports TXD and RXD, and to other modules via I / O ports.

[0051] In this embodiment: Please refer to Figure 1-2 The TMR current measurement module includes: a switching circuit, a TMR current sensing unit, a first operational amplifier circuit unit, a second operational amplifier circuit unit, and a first A / D conversion unit.

[0052] The switching circuit is used to control the activation and deactivation of the TMR current measurement module according to the current measurement control signal from the MCU control module;

[0053] The TMR current sensing unit is used to sense the cable current and output a first analog voltage signal related to the cable current.

[0054] The first operational amplifier circuit unit and the second operational amplifier circuit unit are connected in series between the TMR current sensing unit and the first A / D conversion unit to amplify the first analog voltage signal.

[0055] The first A / D conversion unit is used to convert the amplified first analog voltage signal into a first digital voltage signal, which serves as the initial signal of the cable current.

[0056] By setting up operational amplifier circuits and A / D modules to complete amplification and analog-to-digital conversion, it is convenient for intelligent control by the MCU control module. The addition of a wireless communication module facilitates remote communication, resulting in a high degree of intelligence.

[0057] In this embodiment: Please refer to Figure 2 The switching circuit includes a MOSFET V1 and a capacitor C1; the drain of the MOSFET V1 is connected to the power output terminal of the power management module, the gate of the MOSFET V1 is connected to the current measurement control signal output by the MCU control module, the source of the MOSFET V1 is connected to one end of the capacitor C1 and the TMR current measurement module, and the other end of the capacitor C1 is grounded.

[0058] The MCU control module controls whether the MOSFET V1 is turned on or off by controlling the output PWM signal. When the MOSFET V1 is turned on, the supply voltage VCC supplies power to the TMR current measurement module through the MOSFET V1.

[0059] In this embodiment: Please refer to Figure 2 The TMR current sensing unit includes a TMR sensor U1, a TMR sensor U2, a TMR sensor U3, and an accumulator;

[0060] The TMR sensors U1, U2, and U3 are used to measure the current of the same cable. The power supply terminals of the TMR sensors U1, U2, and U3 are all connected to the source of the MOS transistor V1 in the switching circuit module. The accumulator is connected to the output terminals of the TMR sensors U1, U2, and U3 respectively, and is used to accumulate the current sensing signals output from the TMR sensors U1, U2, and U3 to output the first analog voltage signal related to the cable current.

[0061] Accuracy of detection is ensured by setting three TMR sensors on a single cable. TMR sensors U1, U2, and U3 detect the cable current and output voltage signals, which are input to the accumulator circuit. The output voltage of amplifier U4 is the sum of the voltages output by TMR sensors U1, U2, and U3.

[0062] In this embodiment: Please refer to Figure 2 The first operational amplifier circuit unit includes resistors R4 and R5 and amplifier U4; the output terminal of the accumulator is connected to the non-inverting input of amplifier U4; the inverting input of amplifier U4 is connected to one end of resistor R4 and one end of resistor R5; the other end of resistor R4 is grounded; and the other end of resistor R5 is connected to the output terminal of amplifier U4.

[0063] In this embodiment: Please refer to Figure 2 The second operational amplifier circuit unit includes a resistor R6, an adjustable resistor RP1, and an amplifier U5; the output terminal of the amplifier U4 is connected to the non-inverting terminal of the amplifier U5; the inverting terminal of the amplifier U5 is connected to one end of the resistor R6 and one end of the adjustable resistor RP1; the other end of the resistor R6 is grounded; and the other end of the adjustable resistor RP1 is connected to the output terminal of the amplifier U5.

[0064] In this embodiment: Please refer to Figure 3 The power management module includes a resistor R7, a capacitor C2, and a diode D1;

[0065] One end of resistor R7 is connected to the power supply voltage VCC; the other end of resistor R7 is connected to one end of capacitor C2 and the negative terminal of diode D1; the other end of capacitor C2 is grounded; and the positive terminal of diode D1 is grounded.

[0066] The supply voltage VCC is the sum of the voltages across resistor R7 and diode D1. Diode D1 is a Zener diode with a fixed voltage, which serves as the reference voltage VREF. The power management module also supplies power to other modules; this section only details how the reference voltage is obtained.

[0067] In this embodiment: Please refer to Figure 4 The voltage detection module includes capacitor C3, capacitor C4, capacitor C5, resistor R8, and diode D2;

[0068] One end of capacitor C3 is connected to the first cable to collect voltage L1, one end of capacitor C4 is connected to the second cable to collect voltage L2, one end of capacitor C5 is connected to the third cable to collect voltage L3, the other end of capacitor C3 is connected to the other end of capacitor C4, the other end of capacitor C5, and one end of resistor R8, the other end of resistor R8 is connected to the positive terminal of diode D2, and the negative terminal of diode D2 is connected to the power management module.

[0069] Similar to the TMR current measurement module, the voltage on a single cable is obtained. Here, the voltages L1, L2, and L3 are used to calculate the three-phase power supply of the three cables. Based on the fact that the current in the three power supply cables is equal and the period differs by 120°, under normal conditions, the voltages L1, L2, and L3 pass through capacitors C3, C4, and C5 respectively and have no voltage at resistor R8 (the 120° period difference cancels each other out). When there is an abnormality in the external cable, there is a voltage at resistor R8, which is fed back to the power management module through diode D2. The power management module outputs this signal to the MCU control module, and the MCU control module can issue an alarm based on this information.

[0070] In this embodiment: Please refer to Figure 1 The temperature measurement module includes a temperature sensor, a second operational amplifier circuit unit, and a second A / D conversion unit. The temperature sensor is used to output a second analog voltage signal related to temperature. The second operational amplifier circuit is used to amplify the second analog voltage signal. The second A / D conversion unit is used to convert the amplified second analog voltage signal into a second digital voltage signal, which is then sent to the MCU control module as a temperature sensing signal.

[0071] In this embodiment: Please refer to Figure 1The temperature calibration module is used to generate temperature calibration information based on the second analog voltage signal output by the temperature sensor, and send the temperature calibration information to the MCU control module; the MCU control module is also used to correct the cable current information based on the temperature sensing signal and the temperature calibration information. The corrected cable current is determined by the following formula:

[0072] I cable =k1*I initial *(1+k2*(T-T0))

[0073] Among them, I cable For the corrected cable current, I initial K is the initial signal of the cable current, k1 is the first calibration coefficient indicated by the first calibration signal, k2 is the second calibration coefficient indicated by the second calibration signal, T is the device temperature measured by the temperature measurement module, and T0 is the reference temperature.

[0074] In this embodiment: Please refer to Figure 5 When the current-carrying conductor has an inclination angle α, the offset region of the intersection point within the circular array will become elliptical. When the inclination angle is small, the movement range of the current-carrying conductor within the circular array is shown in the figure below; as the inclination angle gradually increases, the movement range of the ellipse gradually narrows, which restricts the movement position of the current-carrying conductor along the long side of the ellipse. To make the measurement results more accurate, the position of the elliptical array formed by TMR sensors U1, U2, and U3 relative to the cable under test is subject to the following constraints:

[0075]

[0076] Where, k max1 k max2 Here, represents the offset coefficient ranges for the long and short sides of the elliptical array, D is the diameter of the cable, R is the inner diameter of the circular array, and a is the inclination angle of the cable. max k is the maximum tilt angle of the cable. s Let k be the range of movement of the cable along the longer side of the ellipse. s The following equation is obtained by solving:

[0077]

[0078] Where x and y are the offset variables of the cable on the long and short sides of the ellipse, respectively.

[0079] By setting positional constraints on the elliptical array formed by TMR sensors U1, U2, and U3 and the cable under test, the measurement accuracy of the TMR current measurement module can be improved, thereby obtaining more accurate cable current detection results.

[0080] The working principle of this invention is as follows: A switching circuit module receives current measurement control signals from the MCU control module and controls the activation and deactivation of the TMR current measurement module based on these signals. The TMR current measurement module detects cable current information when activated. The voltage detection module detects cable voltage anomalies and feeds back a voltage anomaly signal to the power management module when the cable voltage is abnormal. The power management module provides power to the TMR current measurement module, the voltage detection module, and the MCU control module, and sends the voltage anomaly signal to the MCU control module. The MCU control module generates the current measurement control signal, receives cable current information from the TMR current measurement module, and generates an alarm signal based on the voltage anomaly signal from the power management module. The communication module is connected to the MCU control module to establish communication between the MCU control module and the outside world.

[0081] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0082] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A device for detecting cable current, characterized in that, It includes a TMR flow measurement module, a flow measurement calibration module, a temperature measurement module, a temperature measurement calibration module, and an MCU control module; The TMR current measurement module is used to detect cable current and obtain the initial signal of cable current. The current measurement and calibration module is used to calibrate the initial signal of the cable current and generate a first calibration signal; The temperature measurement module is used to measure the ambient temperature and obtain a temperature signal; The temperature measurement and calibration module is used to calibrate the temperature signal and generate a second calibration signal; The MCU control module is used to receive and determine the corrected cable current based on the initial cable current signal, the first calibration signal, the temperature signal, and the second calibration signal.

2. The device for detecting cable current according to claim 1, characterized in that, The TMR current measurement module includes: a switching circuit, a TMR current sensing unit, a first operational amplifier circuit unit, a second operational amplifier circuit unit, and a first A / D conversion unit; The switching circuit is used to control the activation and deactivation of the TMR current measurement module according to the current measurement control signal from the MCU control module; The TMR current sensing unit is used to sense the cable current and output a first analog voltage signal related to the cable current. The first operational amplifier circuit unit and the second operational amplifier circuit unit are connected in series between the TMR current sensing unit and the first A / D conversion unit to amplify the first analog voltage signal. The first A / D conversion unit is used to convert the amplified first analog voltage signal into a first digital voltage signal, which serves as the initial signal of the cable current.

3. The device for detecting cable current according to claim 2, characterized in that, The TMR current sensing unit includes TMR sensor U1, TMR sensor U2, TMR sensor U3 and an accumulator; The TMR sensors U1, U2, and U3 are used to measure the current of the same cable. The power supply terminals of the TMR sensors U1, U2, and U3 are all connected to the source of the MOS transistor V1 in the switching circuit module. The accumulator is connected to the output terminals of the TMR sensors U1, U2, and U3 respectively, and is used to accumulate the current sensing signals output from the TMR sensors U1, U2, and U3 to output the first analog voltage signal related to the cable current.

4. The device for detecting cable current according to claim 3, characterized in that, The first operational amplifier circuit unit includes resistors R4 and R5 and amplifier U4; the output terminal of the accumulator is connected to the non-inverting input of amplifier U4; the inverting input of amplifier U4 is connected to one end of resistor R4 and one end of resistor R5; the other end of resistor R4 is grounded; the other end of resistor R5 is connected to the output terminal of amplifier U4. The second operational amplifier circuit unit includes a resistor R6, an adjustable resistor RP1, and an amplifier U5; the output terminal of the amplifier U4 is connected to the non-inverting terminal of the amplifier U5; the inverting terminal of the amplifier U5 is connected to one end of the resistor R6 and one end of the adjustable resistor RP1; the other end of the resistor R6 is grounded; and the other end of the adjustable resistor RP1 is connected to the output terminal of the amplifier U5.

5. The device for detecting cable current according to claim 3, characterized in that, The elliptical array formed by TMR sensors U1, U2, and U3 and the position of the cable under test are subject to the following constraints: Where, k max1 k max2 Here, represents the offset coefficient ranges for the long and short sides of the elliptical array, D is the diameter of the cable, R is the inner diameter of the circular array, and a is the inclination angle of the cable. max k is the maximum tilt angle of the cable. s Let k be the range of movement of the cable along the longer side of the ellipse. s The following equation is obtained by solving: Where x and y are the offset variables of the cable on the long and short sides of the ellipse, respectively.

6. The device for detecting cable current according to claim 1, characterized in that, Also includes: Power management module and voltage detection module; The power management module is used to provide power to the TMR current measurement module, the voltage detection module and the MCU control module, and to forward the voltage abnormality signal to the MCU control module; The voltage detection module is used to detect abnormalities in cable voltage and to send a voltage abnormality signal back to the power management module when the cable voltage is abnormal.

7. The device for detecting cable current according to claim 6, characterized in that, The power management module includes a resistor R7, a capacitor C2, and a diode D1; one end of the resistor R7 is connected to the supply voltage VCC; the other end of the resistor R7 is connected to one end of the capacitor C2 and the negative terminal of the diode D1; the other end of the capacitor C2 is grounded; and the positive terminal of the diode D1 is grounded. The voltage detection module includes capacitor C3, capacitor C4, capacitor C5, resistor R8, and diode D2; One end of capacitor C3 is connected to the first cable to collect voltage L1, one end of capacitor C4 is connected to the second cable to collect voltage L2, one end of capacitor C5 is connected to the third cable to collect voltage L3, the other end of capacitor C3 is connected to the other end of capacitor C4, the other end of capacitor C5, and one end of resistor R8, the other end of resistor R8 is connected to the positive terminal of diode D2, and the negative terminal of diode D2 is connected to the power management module.

8. The device for detecting cable current according to claim 1, characterized in that, Also includes: The temperature measurement module includes a temperature sensor, a second operational amplifier circuit unit, and a second A / D conversion unit. The temperature sensor is used to output a second analog voltage signal related to temperature. The second operational amplifier circuit is used to amplify the second analog voltage signal. The second A / D conversion unit is used to convert the amplified second analog voltage signal into a second digital voltage signal, which is then sent to the MCU control module as a temperature sensing signal.

9. The device for detecting cable current according to claim 1, characterized in that, The corrected cable current is determined by the following formula: I cable =k1*I initial *(1+k2*(T-T0)) Among them, I cable For the corrected cable current, I initial K is the initial signal of the cable current, k1 is the first calibration coefficient indicated by the first calibration signal, k2 is the second calibration coefficient indicated by the second calibration signal, T is the device temperature measured by the temperature measurement module, and T0 is the reference temperature.

10. A method for detecting cable current, employing the apparatus for detecting cable current as described in any one of claims 1-9, characterized in that, Includes the following steps: The cable current is detected by the TMR current measurement module to obtain the initial signal of the cable current; The initial signal of the cable current is calibrated by the current measurement and calibration module to generate a first calibration signal; The ambient temperature is measured by the temperature measurement module to obtain a temperature signal; The temperature signal is calibrated by the temperature measurement and calibration module to generate a second calibration signal; The MCU control module receives and determines the corrected cable current based on the initial cable current signal, the first calibration signal, the temperature signal, and the second calibration signal.

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