Current measuring circuit for clamp type current sensor

Abstract

The utility model relates to a current measuring circuit for a clamp type current sensor. The device comprises a measurement processor, a clamp head opening and closing detection device and a current measurement main unit, and only when the clamp head opening and closing detection device loads a clamp head closing locking state signal to the measurement processor, the measurement processor configures the current measurement main unit to enter a current measurement state; the current measurement main unit comprises a magnetic flux type current measurement circuit, the magnetic flux type current measurement circuit is adaptively connected with an induction magnetic core unit in the clamp head, the induction magnetic core unit in the clamp head comprises two butted induction magnetic cores, and when the clamp head is closed, the two butted induction magnetic cores are connected in series to form a current measurement induction magnetic core. Current measurement is carried out based on the connection between the current measurement induction magnetic core and the magnetic flux type current measurement circuit. According to the utility model, the current measurement stability and reliability of the clamp-type current sensor can be improved, and the service life of the clamp-type current sensor can be prolonged.

Description

Technical Field

[0001] This utility model relates to a current measurement circuit, and more particularly to a current measurement circuit for a clamp-on current sensor. Background Technology

[0002] Clamp-on current sensors can be used to measure DC or AC current. They are easy to open and close, eliminating the need to disconnect the current bus during measurement and saving time by avoiding the process of disassembling and reassembling the current bus, thus significantly improving testing efficiency. When measuring current, the basic structure of a clamp-on current sensor can be based on open-loop or closed-loop Hall effect principles. While convenient and easy to use, this affects measurement accuracy and does not meet the requirements of high-precision measurement applications. To further improve the accuracy and stability of current measurement, the basic structure of a clamp-on current sensor can be based on magnetic modulation or fluxgate principles.

[0003] Current sensors based on magnetic modulation or fluxgate magnetization are closed-loop feedback zero-flux sensors capable of measuring both DC and AC currents with high accuracy. Their operating principle is based on the magnetic saturation of an internally driven magnetic core through alternating excitation. For closed-type (non-opening) current sensors, the core characteristics are essentially fixed, the excitation is relatively stable, and circuit implementation is relatively easy. However, for clamp-type (opening) structures, the magnetic circuit and core characteristics differ significantly between the closed and open states. In the open state, leakage flux is substantial, making it difficult for the excitation circuit to saturate the open core. Therefore, clamp-type current sensors cannot measure current when in the open state. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a current measurement circuit for clamp current sensors, which can improve the stability and reliability of current measurement by clamp current sensors and extend the service life of clamp current sensors.

[0005] According to the technical solution provided by this utility model, a current measurement circuit for a clamp-on current sensor includes a measurement processor, a clamp opening / closing detection device for detecting the opening / closing state of the clamp-on current sensor, and a current measurement main unit for performing current measurement.

[0006] Both the jaw opening and closing detection device and the current measurement main unit are electrically connected to the measurement processor. The measurement processor only configures the current measurement main unit to enter the current measurement state when the jaw opening and closing detection device wants the measurement processor to load the jaw closing and locking state signal.

[0007] The main current measurement unit includes a flux-type current measurement circuit, which is adapted and connected to the induction magnetic core unit inside the clamp head.

[0008] The induction core unit inside the clamp head includes two matched induction cores. When the clamp head is closed, the two matched induction cores are connected in series to form a current measuring induction core.

[0009] Current measurement is performed based on the connection between the current measuring induction core and the flux current measuring circuit, and the measured current value is output through the flux current measuring circuit.

[0010] The clamp opening / closing position detection device includes a locking detection switch unit and a closing locking trigger mechanism for triggering the locking detection switch unit, wherein...

[0011] The locking detection switch unit is electrically connected to the measurement processor;

[0012] When the jaws are in the closed state, the closing locking trigger mechanism triggers the locking detection switch unit, which then sends a jaw closing locking status signal to the measurement processor.

[0013] The closing locking trigger mechanism includes at least a push handle for locking the clamp head position, wherein...

[0014] The lock detection switch unit includes a lock detection switch adapted to the push handle and a switching circuit adapted to and connected to the lock detection switch.

[0015] When the jaws are closed, the push handle pushes the locking detection switch to close. Based on the closed locking detection switch, the switch circuit loads the jaw closure locking status signal into the measurement processor.

[0016] The switching circuit includes a debounce capacitor connected in parallel with the lock detection switch, wherein,

[0017] The first end of the anti-shake capacitor is connected to one end of the switch resistor and one end of the lock detection switch, and the first end of the anti-shake capacitor is connected to the measurement processor;

[0018] The second terminal of the anti-shake capacitor and the other terminal of the lock detection switch are both grounded.

[0019] The pliers head includes two fitting pliers housings, with each inductive magnetic core assembled within one pliers housing.

[0020] After the two jaw shells are aligned and in contact, the jaws are in a closed state. At the same time, the induction magnetic cores are aligned and in contact, and connected in series to form a current measuring induction magnetic core.

[0021] The flux-type current measurement circuit includes a modulation circuit for modulating the current measurement sensing core, a flux self-recovery circuit for flux recovery operation, and a main feedback circuit for flux recovery compensation.

[0022] The modulation circuit is adapted to the current measurement induced magnetic flux and connected to the main feedback circuit, and is also connected to the main feedback circuit through the magnetic flux self-recovery circuit.

[0023] The output of the main feedback circuit is adapted to the secondary winding of the current measurement induction core.

[0024] The main feedback circuit includes a main feedback operational amplifier OA1 and a power amplifier PA, wherein...

[0025] The non-inverting input of the main feedback operational amplifier OA1 is grounded. The inverting input of the main feedback operational amplifier OA1 is connected to one end of resistor R3, one end of resistor R4, and one end of resistor R2. The other end of resistor R3 is connected to the flux self-recovery circuit, and the other end of resistor R4 is connected to the modulation circuit.

[0026] The other end of resistor R2 is connected to one end of capacitor C2, and the other end of capacitor C2 is connected to the output of main feedback operational amplifier OA1 and the input of power amplifier PA.

[0027] The output terminal of the power amplifier PA is adapted to be connected to the secondary winding of the current measuring induction core.

[0028] The flux self-recovery circuit includes a demodulation circuit, a flux detection circuit, and a self-recovery excitation circuit connected in sequence.

[0029] The demodulation circuit is connected to the modulation circuit, and the self-recovery excitation circuit is connected to the inverting input of the main feedback operational amplifier OA1 via the bottom single group R3.

[0030] The modulation circuit is a self-resonant excitation circuit or a fixed-frequency excitation circuit.

[0031] The measurement processor includes an MCU unit.

[0032] The advantages of this invention are as follows: When the clamp-on current sensor uses a flux-type current sensor for current measurement, the clamp opening and closing detection device detects the opening and closing state of the clamp head. The main current measurement unit is only activated to perform current measurement when the clamp head is in the closed state. This avoids damage to components caused by the main current measurement unit being in a self-recovery state. As a result, the stability and reliability of current measurement by the clamp-on current sensor can be improved, and the service life of the clamp-on current sensor can be extended. Attached Figure Description

[0033] Figure 1 This is a structural block diagram of one embodiment of the current measurement circuit of this utility model.

[0034] Figure 2 This is a circuit diagram of one embodiment of the locking detection switch unit of this utility model.

[0035] Figure 3 This is a circuit diagram of one embodiment of the main current measurement unit of a utility model. Detailed Implementation

[0036] The present invention will be further described below with reference to the specific accompanying drawings and embodiments.

[0037] It should be understood that flux-modulated or fluxgate-based current sensors, relying on closed-loop feedback, can only operate in a zero-flux state. Therefore, they must be paired with a self-recovery circuit to recover from abnormal states such as saturation. As explained above, when the clamp is open, the zero-flux current sensor cannot operate. In this case, the self-recovery circuit is activated for scanning. During repeated large-range scanning, components such as the power amplifier are subjected to significant stress, increasing the likelihood of damage. Therefore, existing clamp-on current sensors are prone to damage during measurement, resulting in a shorter lifespan and higher operating costs.

[0038] To improve the stability and reliability of current measurement using clamp-on current sensors and extend their service life, this invention provides a current measurement circuit for clamp-on current sensors. Specifically, it includes a measurement processor, a clamp opening / closing detection device for detecting the clamp opening / closing state of the clamp-on current sensor, and a main current measurement unit for performing current measurement.

[0039] Both the jaw opening and closing detection device and the current measurement main unit are electrically connected to the measurement processor. The measurement processor only configures the current measurement main unit to enter the current measurement state when the jaw opening and closing detection device wants the measurement processor to load the jaw closing and locking state signal.

[0040] The main current measurement unit includes a flux-type current measurement circuit, which is adapted and connected to the induction magnetic core unit inside the clamp head.

[0041] The induction core unit inside the clamp head includes two matched induction cores. When the clamp head is closed, the two matched induction cores are connected in series to form a current measuring induction core.

[0042] Current measurement is performed based on the connection between the current measuring induction core and the flux current measuring circuit, and the measured current value is output through the flux current measuring circuit.

[0043] It should be understood that clamp current sensor specifically refers to a clamp-type current sensor that can be opened and closed. The opening and closing of clamp current sensor generally refers to the opening and closing of the clamp head of the clamp current sensor. As can be seen from the above description, when the clamp head is open, it can be easily matched with the current bus. The structural form of clamp current sensor can be consistent with the existing technology, which will not be elaborated here.

[0044] In practical implementation, the current measurement circuit should include a measurement processor. Generally, the measurement processor includes an MCU (Microcontroller Unit) unit. For example, the measurement processor can be a commonly used microprocessor. The type of measurement processor can be selected as needed.

[0045] To prevent the self-recovery scan from being initiated even when the clamp head is open, this embodiment of the invention utilizes a clamp head opening / closing detection device to detect the opening / closing state of the clamp head of the clamp-type current sensor. Specifically, detecting the opening / closing state means determining whether the clamp head is open or closed. As explained above, current measurement is not possible when the clamp head is open, but it is possible when the clamp head is closed. In practice, when the clamp head opening / closing detection device determines that the clamp head is closed, it loads a clamp head closed lock signal into the measurement processor; conversely, when it determines that the clamp head is open, it loads a clamp head open signal into the measurement processor.

[0046] In one embodiment of this invention, the measurement processor only configures the current measurement main unit to enter the current measurement state when it receives a clamping head closed / locked state signal; that is, when it receives a clamping head open state signal, it configures the current measurement main unit to be in a non-current measurement state. Generally, being in a non-current measurement state means that the current measurement main unit is in a non-operating state. In specific implementations, this can be achieved by shutting off the power supply to the current measurement main unit, or by using a control method with an enable function. In this case, the current measurement main unit should be in a non-enabled state, specifically designed to prevent the current measurement main unit from performing current measurements. Further examples will not be provided here.

[0047] To improve the accuracy of current measurement, the main current measurement unit can adopt a flux-type current measurement circuit, such as... Figure 1 As shown. When the main current measurement unit adopts a flux-type current measurement circuit, the clamp current sensor of this utility model becomes a flux-type current sensor. At this time, the clamp current sensor should work in a zero flux state. When the flux state of the clamp current sensor is non-zero, it indicates that the clamp current sensor is in an abnormal state.

[0048] In order to realize flux current measurement, the flux current measurement circuit of this utility model is adapted and connected to the induction core unit inside the clamp head. The induction core unit generally includes two induction cores, which are matched and connected. Specifically, when the clamp head is closed, the two induction cores can be connected in series to form a current measurement induction core, while when the clamp head is open, the two induction cores are in a free state of separation. Figure 3 The image shows an embodiment of two induction cores connected in series to form a current-measuring induction core. Figure 3 In the diagram, T1 and T2 are two induction magnetic cores. When they are connected in series to form a current measurement induction magnetic core, the primary winding of induction magnetic core T1 is connected to the primary winding of induction magnetic core T2. At the same time, the secondary winding of induction magnetic core T1 is connected to the corresponding secondary winding of induction magnetic core T2. The winding terminals with the same name are the same. The specific connection is based on the requirement of being able to form a current measurement induction magnetic core in series.

[0049] After the current measuring induction core is formed, the flux current measuring circuit is connected and cooperated with the current measuring induction core to form the current measuring configuration of the existing flux current sensor. After that, the current bus passing through the clamp head can be measured, and the measured current value can be output through the flux current measuring circuit.

[0050] In one embodiment of this utility model, the clamp opening / closing position detection device includes a locking detection switch unit and a closing locking trigger mechanism for triggering the locking detection switch unit, wherein...

[0051] The locking detection switch unit is electrically connected to the measurement processor;

[0052] When the jaws are in the closed state, the closing locking trigger mechanism triggers the locking detection switch unit, which then sends a jaw closing locking status signal to the measurement processor.

[0053] In order to detect the opening and closing position of the pliers, the pliers opening and closing position detection device may include a locking detection switch unit and a closing locking trigger mechanism. The locking detection switch unit may have the characteristics of a switch. The locking detection switch unit should be electrically connected to the measurement processor so as to load a pliers closing locking state signal or a pliers opening state signal to the measurement processor.

[0054] Specifically, when the jaws are in the closed state, the closing locking trigger mechanism will trigger the locking detection switch unit. At this time, the locking detection switch unit will load the jaws closed locking state signal to the measurement processor. When the jaws are in the open state, the closing locking trigger mechanism will not trigger the locking detection switch unit. At this time, the locking detection switch unit can load the jaws open state signal to the measurement processor.

[0055] In one embodiment of this utility model, the closing locking trigger mechanism includes at least a push handle for locking the clamp head position, wherein...

[0056] The lock detection switch unit includes a lock detection switch adapted to the push handle and a switching circuit adapted to and connected to the lock detection switch.

[0057] When the jaws are closed, the push handle pushes the locking detection switch to close. Based on the closed locking detection switch, the switch circuit loads the jaw closure locking status signal into the measurement processor.

[0058] Specifically, the closing and locking triggering mechanism can be a mechanical structure housed within the clamp-on current sensor, such as a push handle, for example, the closing and locking triggering mechanism may include a push handle, such as... Figure 1 As shown, the push handle typically moves with the pliers head. When the pliers head is closed, the push handle triggers the locking detection switch; when the pliers head is open, the push handle disengages from the locking detection switch, preventing it from being triggered. In practice, the locking detection switch is generally a push-triggered switch. Figure 2 In this context, S1 is the lock detection switch.

[0059] In one embodiment of this utility model, the switching circuit includes a debounce capacitor connected in parallel with the lock detection switch, wherein,

[0060] The first end of the anti-shake capacitor is connected to one end of the switch resistor and one end of the lock detection switch, and the first end of the anti-shake capacitor is connected to the measurement processor;

[0061] The second terminal of the anti-shake capacitor and the other terminal of the lock detection switch are both grounded.

[0062] Figure 2 An embodiment of a switching circuit is shown in the figure. Figure 2 In the diagram, capacitor C1 is the anti-shake capacitor, and resistor R1 is the switching resistor. The other end of the switching resistor should also be connected to the power supply VCC. Normally, the lock detection switch is in the open state, at which time the voltage across the first terminal of the anti-shake capacitor is high. However, when the lock detection switch is pushed closed, it short-circuits the anti-shake capacitor, at which point the voltage across the first terminal of the anti-shake capacitor is low.

[0063] Since the first end of the anti-shake capacitor is connected to the measurement processor, the measurement processor can determine whether the clamp is in a closed or open state based on the voltage level of the first end of the anti-shake capacitor.

[0064] Of course, the clamp opening and closing detection device can also take other forms, depending on whether it can meet the requirements for detecting the opening and closing state of the clamp head. These will not be listed here.

[0065] In one embodiment of this utility model, the pliers head includes two matching pliers head shells, with each induction magnetic core assembled inside one pliers head shell, wherein...

[0066] After the two jaw shells are aligned and in contact, the jaws are in a closed state. At the same time, the induction magnetic cores are aligned and in contact, and connected in series to form a current measuring induction magnetic core.

[0067] To enable the pliers to open and close, the pliers typically include two fitting plier shells. These shells are usually hinged. When the two shells are far apart, the pliers are open; when they are aligned and in contact, the pliers are closed. The alignment can be achieved using common methods such as a fork joint. The alignment method can be selected based on requirements to ensure the two inductive magnetic cores can be aligned and connected in series. In practice, the two inductive magnetic cores are typically assembled separately within one plier shell. When the shells are far apart, the two inductive magnetic cores separate from their aligned and connected state. When they are aligned and in contact, the two inductive magnetic cores are aligned and connected in series to form a current-measuring inductive magnetic core.

[0068] It should be noted that the assembly of the clamp head housing and the induction magnetic core within the clamp head housing can be consistent with existing technology, specifically to meet the requirements of the aforementioned flux-type current measurement. Generally, the two induction magnetic cores can adopt the same form, such as having the corresponding windings of the two induction magnetic cores in the same state, so that they can be connected in series to form a current-measuring induction magnetic core, thus forming the required induction magnetic core state.

[0069] In one embodiment of this utility model, the flux-type current measurement circuit includes a modulation circuit for modulating the current measurement sensing magnetic core, a flux self-recovery circuit for flux recovery operation, and a main feedback circuit for flux recovery compensation.

[0070] The modulation circuit is adapted to the current measurement induced magnetic flux and connected to the main feedback circuit, and is also connected to the main feedback circuit through the magnetic flux self-recovery circuit.

[0071] The output of the main feedback circuit is adapted to the secondary winding of the current measurement induction core.

[0072] In order to achieve flux-type current measurement in conjunction with the current-sensing magnetic core, the flux-type current measurement circuit should include a modulation circuit, a flux self-recovery circuit, and a main feedback circuit. The modulation circuit is used to modulate the current-sensing magnetic core to generate alternating saturated magnetic flux after modulation. The modulation circuit can adopt a commonly used form to meet the requirements of current-sensing magnetic core modulation and current measurement.

[0073] It is understandable that a flux self-recovery circuit is a circuit that restores magnetic flux to a zero flux state. The working principle of the flux self-recovery circuit is consistent with the self-recovery mechanism of existing flux-type current sensors. The modulation circuit and the flux self-recovery circuit should be adapted and connected to the main feedback circuit. The main feedback circuit can provide a compensation current, which should be applied to the current-sensing magnetic core. Figure 3 In the process, the compensation current will be applied to the secondary winding of the induction core T1.

[0074] In one embodiment of this utility model, the main feedback circuit includes a main feedback operational amplifier OA1 and a power amplifier PA, wherein...

[0075] The non-inverting input of the main feedback operational amplifier OA1 is grounded. The inverting input of the main feedback operational amplifier OA1 is connected to one end of resistor R3, one end of resistor R4, and one end of resistor R2. The other end of resistor R3 is connected to the flux self-recovery circuit, and the other end of resistor R4 is connected to the modulation circuit.

[0076] The other end of resistor R2 is connected to one end of capacitor C2, and the other end of capacitor C2 is connected to the output of main feedback operational amplifier OA1 and the input of power amplifier PA.

[0077] The output terminal of the power amplifier PA is adapted to be connected to the secondary winding of the current measuring induction core.

[0078] Specifically, when the modulation circuit is connected to the inverting input of the main feedback operational amplifier OA1 via resistor R4, the modulated signal is loaded onto the main feedback operational amplifier OA1. That is, in addition to modulating the current-sensing magnetic core, the modulation signal should also be loaded onto the main feedback operational amplifier OA1. The modulation signal is generally an AC signal.

[0079] In one embodiment of this utility model, the magnetic flux self-recovery circuit includes a demodulation circuit, a magnetic flux detection circuit, and a self-recovery excitation circuit connected in sequence, wherein...

[0080] The demodulation circuit is connected to the modulation circuit, and the self-recovery excitation circuit is connected to the inverting input of the main feedback operational amplifier OA1 via the bottom single group R3.

[0081] Specifically, the demodulation circuit is adapted to the modulation circuit so that the modulated signal can be demodulated. Figure 3 The modulation and demodulation circuit in the diagram includes both a modulation circuit and a demodulation circuit. The modulation circuit is either a self-resonant excitation circuit or a fixed-frequency excitation circuit. It is understood that when different types of modulation circuits are used, the demodulation form of the modulated signal will also differ.

[0082] The demodulation circuit can load a demodulation status signal onto the flux detection circuit; the flux detection circuit detects and processes the demodulation status signal and loads a flux detection signal onto the self-recovery excitation circuit; based on the flux detection signal, the self-recovery excitation circuit determines the current flux status information.

[0083] In practice, the magnetic flux detection circuit detects and processes the demodulated state signal, mainly by performing necessary processing on the demodulated state signal to meet the requirements of the self-recovery excitation circuit for parsing the magnetic flux state information.

[0084] Understandably, the self-recovering excitation circuit's method of interpreting the flux detection signal will differ depending on the modulation circuit's form. For example, when the modulation circuit uses a self-resonant excitation method, the modulation signal is a square wave. After passing through the demodulation circuit and the flux detection circuit, the self-recovering excitation circuit can calculate the square wave frequency of the demodulated state signal. Specifically, the square wave signal has the lowest frequency when in a zero flux state. When in a non-zero flux state, the oscillation frequency increases. The further it deviates from the zero flux state, the higher the oscillation frequency, and the square wave waveform becomes distorted. It stops oscillating when it reaches a certain level. Therefore, the self-recovering excitation circuit can determine whether the current state is zero or non-zero flux based on the calculated square wave frequency. The specific method for calculating the square wave frequency is consistent with existing technologies and will not be elaborated here.

[0085] As can be seen from the above description, when the modulation circuit uses fixed frequency excitation, the signal amplitude is different in the zero flux state and the non-zero flux state. Therefore, the analytical method for the self-recovery excitation circuit to solve the flux detection state signal should be amplitude detection. The zero flux state or the non-zero flux state is determined based on the amplitude state. The specific method for solving the amplitude can be consistent with the existing technology, and will not be elaborated here.

[0086] In practice, the demodulation circuit, magnetic flux detection circuit, and self-recovery excitation circuit can all adopt commonly used circuit forms. The specific methods and processes for achieving self-recovery capability can be consistent with existing technologies, and will not be elaborated here.

[0087] The following example illustrates the current measurement process of the clamp-on current sensor of this utility model. Specifically:

[0088] After the measurement processor is configured with the current measurement main unit and enters the current measurement state, the modulator outputs a modulation signal. The modulation signal serves as the excitation waveform for the current measurement induction core. When the current measurement induction core is excited, it will excite induction cores T1 and T2. The primary bus current signal is demodulated by the demodulation circuit and sent to the inverting input of the main feedback operational amplifier OA1. Through resistor R2 and capacitor C, the output of the main feedback operational amplifier OA1 provides a feedback compensation signal to the power amplifier PA. The power amplifier PA drives the secondary winding of the current measurement induction core. When the current in the secondary winding and the bus current achieve equal ampere-turn compensation, the coil and core are in a zero flux state.

[0089] If the current-measuring sensing core is in a non-zero flux state, the flux self-recovery circuit starts working. Through the integration effect of resistor R3 and capacitor C2, it outputs a rising or falling waveform to achieve the output of the recovery signal. When the zero flux state is reached, the flux self-recovery circuit shuts down. As can be seen from the above description, the method and process by which the flux self-recovery circuit regulates the non-zero flux state to the zero flux state are consistent with existing technology, and will not be repeated here.

Claims

1. A current measurement circuit for a clamp-on current sensor, characterized by, The current measurement device comprises a measurement processor, a jaw opening and closing detection device for detecting the opening and closing state of the jaw of a clamp-on current sensor, and a current measurement main unit for performing current measurement, wherein The jaw opening and closing detection device and the current measurement main unit are electrically connected to the measurement processor, and the measurement processor is configured to load the current measurement main unit into a current measurement state only when the jaw opening and closing detection device loads a jaw closed locking state signal to the measurement processor; The current measurement main unit comprises a magnetic flux type current measurement circuit, which is adaptively connected to an induction magnetic core unit in the jaw, wherein The induction magnetic core unit in the jaw comprises two induction magnetic cores which are connected in series to form a current measurement induction magnetic core when the jaw is closed, The current measurement is performed based on the connection between the current measurement induction magnetic core and the magnetic flux type current measurement circuit, and the measured current value is output through the magnetic flux type current measurement circuit.

2. The current measurement circuit for a clamp-on current sensor according to claim 1, characterized by: The jaw opening and closing position detection device comprises a locking detection switch unit and a closed locking trigger mechanism for triggering the locking detection switch unit, wherein The locking detection switch unit is electrically connected to the measurement processor; When the jaw is in a closed state, the closed locking trigger mechanism triggers the locking detection switch unit, and the locking detection switch unit loads a jaw closed locking state signal to the measurement processor.

3. The current measurement circuit for a current sense transformer according to claim 2, characterized in that: The closed locking trigger mechanism comprises at least a push handle for locking the position of the jaw, wherein The locking detection switch unit comprises a locking detection switch adapted to the push handle and a switching value circuit adapted to the locking detection switch, When the jaw is closed, the push handle pushes the locking detection switch to close, and the switching value circuit is configured to load a jaw closed locking state signal to the measurement processor based on the closed locking detection switch.

4. The current measurement circuit for a current sense transformer according to claim 3, characterized in that: The switching value circuit comprises an anti-jitter capacitor connected in parallel with the locking detection switch, wherein The first end of the anti-jitter capacitor is connected to one end of a switching value resistor and one end of the locking detection switch, and the first end of the anti-jitter capacitor is connected to the measurement processor; The second end of the anti-jitter capacitor and the other end of the locking detection switch are both grounded.

5. The current measurement circuit for a clamp current sensor according to claim 1, characterized by: The jaw comprises two adapted jaw shells, and each induction magnetic core is assembled in one jaw shell, wherein After the two jaw shells are aligned and contacted, the jaw is in a closed state, and at the same time, the induction magnetic cores are aligned and contacted, and are connected in series to form a current measurement induction magnetic core.

6. The current measurement circuit for a current sense transformer according to any one of claims 1 to 5, characterized in that: The magnetic flux type current measurement circuit comprises a modulation circuit for modulating the current measurement induction magnetic core, a magnetic flux self-recovery circuit for magnetic flux recovery operation, and a main feedback circuit for magnetic flux recovery compensation, wherein The modulation circuit is adaptively connected to the current measurement induction magnetic flux and connected to the main feedback circuit, and connected to the main feedback circuit through the magnetic flux self-recovery circuit; The output end of the main feedback circuit is adaptively connected to the secondary winding of the current measurement induction magnetic core.

7. The current measurement circuit for a current sense transformer according to claim 6, characterized in that: The main feedback circuit comprises a main feedback operational amplifier OA1 and a power amplifier PA, wherein The non-inverting terminal of the main feedback operational amplifier OA1 is grounded, the inverting terminal of the main feedback operational amplifier OA1 is connected to one end of a resistor R3, one end of a resistor R4, and one end of a resistor R2, the other end of the resistor R3 is connected to the magnetic flux self-recovery circuit, and the other end of the resistor R4 is connected to the modulation circuit; The other end of the resistor R2 is connected with one end of the capacitor C2, and the other end of the capacitor C2 is connected with the output end of the main feedback operational amplifier OA1 and the input end of the power amplifier PA. The output end of the power amplifier PA is connected with the secondary winding of the current measurement induction magnetic core.

8. The current measurement circuit for a current sense transformer according to claim 6, characterized in that: The magnetic flux self-recovery circuit comprises a demodulation circuit, a magnetic flux detection circuit and a self-recovery excitation circuit connected in sequence, wherein, The demodulation circuit is connected with the modulation circuit, and the self-recovery excitation circuit is connected with the inverting terminal of the main feedback operational amplifier OA1 through a single group of resistors R3.

9. The current measurement circuit for a current sense transformer according to claim 6, characterized in that: The modulation circuit is a self-resonance excitation circuit or a frequency fixed excitation circuit.

10. The current measurement circuit for a clamp-on current sensor according to any one of claims 1 to 5, characterized by: The measurement processor comprises an MCU unit.

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