Current sensor, current detection circuit and power supply device

Abstract

The present invention provides a current sensor, a current detection circuit and a power supply device. The current sensor includes: a current conductor, a magnetic sensor structure, a first signal amplification unit and a second signal amplification unit. The current conductor is suitable for connecting to a measured current port to access the measured current; the magnetic sensor structure is configured to be above the current conductor, and the magnetic sensor structure is used to sense the magnetic signal generated by the measured current and form an electrical signal; the first signal amplification unit is used to receive the electrical signal output by the magnetic sensor structure, and amplify the electrical signal once to form a first conditioned signal; the second signal amplification unit forms a second conditioned signal; the first conditioned signal and the second conditioned signal are respectively used to characterize the magnitude of the measured current under different ranges. The first conditioned signal characterizes the magnitude of the large-range current, and the second conditioned signal characterizes the magnitude of the small-range current, so as to realize dual-range measurement of large and small currents, which is widely applicable; and the detection of arc current is realized at the same time.

Description

Technical Field

[0001] The present invention relates to the technical field of sensors, and in particular to a current sensor, a current detection circuit and a power supply device. Background Art

[0002] The current sensor is an interface device between high and low voltages that uses the magnetic field generated by the current to detect the current value under the state of electrical insulation. It is mainly divided into four categories: Hall current sensor, anisotropic magnetoresistance (AMR) current sensor, giant magnetoresistance (GMR) current sensor, and tunnel junction magnetic (TMR) current sensor.

[0003] Most of the current sensors with existing structures can only test the current in a single range, with single functions and limited current measurement range, which makes it difficult to meet the needs of dual-range current measurement. Alternatively, in order to measure currents of two different ranges, two current sensors are used, one with a large range and the other with a small range. However, the use of two sensors increases the volume and cost, and also brings inconvenience to use. At the same time, when the photovoltaic inverter panel is used outdoors for a long time, the cable will age and the contact will be poor, which may cause arcing in normal use, and in severe cases, high temperature fire will occur, which poses a great safety hazard. Summary of the invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defects of the prior art that multiple sensors are used to achieve multi-range detection, which causes an increase in volume and cost, and also brings inconvenience to use; at the same time, when the photovoltaic inverter panel is used outdoors for a long time, cable aging, poor contact and other phenomena will occur, which may cause electric arcs in normal use, and in severe cases, high-temperature fires may occur, posing a major safety hazard.

[0005] Therefore, the present invention provides a current sensor, comprising:

[0006] A current conductor, wherein the current conductor is suitable for being connected to a current port to be measured so as to receive a current to be measured;

[0007] A magnetic sensor structure is configured to be above the current conductor, the magnetic sensor structure is used to sense the magnetic signal generated by the measured current and form an electrical signal;

[0008] A first signal amplifying unit, configured to receive the electrical signal output by the magnetic sensor structure, and amplify the electrical signal once to form a first conditioned signal;

[0009] A second signal amplifying unit, used for receiving the first filtered signal and amplifying the first filtered signal twice to form a second conditioned signal; wherein the first filtered signal is a signal obtained after an external first auxiliary circuit receives the first conditioned signal and processes the first conditioned signal;

[0010] The first conditioned signal and the second conditioned signal are respectively used to characterize the magnitude of the measured current under different ranges.

[0011] Optionally, in the above-mentioned current sensor, the current wire comprises a first branch arm and the second branch arm, and the current flowing in the first branch arm is opposite to the current flowing in the second branch arm;

[0012] The magnetic sensor structure includes a first magnetic sensor chip and a second magnetic sensor chip. The magnetic sensor chip is used to sense the magnetic signal generated by the measured current through a magnetic sensing element and convert the magnetic signal into an electrical signal. The first magnetic sensor chip is arranged on the first arm, and the second magnetic sensor chip is arranged on the second arm.

[0013] Optionally, in the above current sensor, the first magnetic sensor chip includes a first magnetic resistor and a third magnetic resistor, and the second magnetic sensor chip includes a second magnetic resistor and a fourth magnetic resistor;

[0014] The first magnetoresistance, the second magnetoresistance, the third magnetoresistance and the fourth magnetoresistance are configured as a full-bridge bridge circuit.

[0015] Optionally, in the above-mentioned current sensor, the first signal amplifying unit and the second signal amplifying unit are programmable operational amplifiers.

[0016] Optionally, in the above-mentioned current sensor, the programmable operational amplifier includes: at least two operational amplifiers, a decoder module and a resistor switch array module connected to each other, the multiple operational amplifiers connected to each other are used to amplify the electrical signal or the second conditioned signal step by step, and the decoding result output by the decoder module is used to control the attenuation amount of the input signal by the resistor switch array module.

[0017] Optionally, the above-mentioned current sensor also includes a base frame structure, which includes a substrate and a frame, the first signal amplification unit, the second signal amplification unit and the magnetic sensor structure are arranged on the substrate, the substrate is arranged on the frame, and the frame is integrally formed with the substrate or detachably connected.

[0018] Optionally, the above-mentioned current sensor further includes: wire pins arranged at the edge of the substrate, and each end of each of the current wires is respectively connected to one or more of the wire pins.

[0019] The present invention also provides a current detection circuit, comprising the above-mentioned current sensor, a first auxiliary circuit and a second auxiliary circuit;

[0020] Among them, the first auxiliary circuit is arranged between the first signal amplifying unit and the second signal amplifying unit, and is used to receive the first conditioned signal, obtain the first filtered signal after noise reduction of the first conditioned signal, and output it to the second signal amplifying unit side; the second auxiliary circuit is arranged on the output end side of the second signal amplifying unit, and is used to obtain the second filtered signal after noise reduction of the second conditioned signal.

[0021] Optionally, in the above-mentioned current detection circuit, the first auxiliary circuit includes a filter circuit, and the filter circuit is used to filter the interference signal of the first conditioned signal to obtain the first filtered signal;

[0022] and / or,

[0023] The second auxiliary circuit includes a filter circuit, and the filter circuit is used to filter the interference signal of the second conditioned signal to obtain the second filtered signal.

[0024] Optionally, in the above-mentioned current detection circuit, the first auxiliary circuit includes a first resistor, the first signal amplifying unit outputs a first conditioned signal, the first conditioned signal is used to detect the magnitude of the current to be measured under a large output range, the first conditioned signal is processed by the first resistor to obtain a first filtered signal, the first filtered signal is processed by the second signal amplifying unit to obtain the second conditioned signal, and the second conditioned signal is used to detect the magnitude of the current to be measured under a small output range;

[0025] or,

[0026] The first auxiliary circuit includes a first capacitor, and the first signal amplifying unit outputs a first conditioned signal, the first conditioned signal is used to detect the magnitude of the measured current under a large output range, the first conditioned signal is processed by the first capacitor and filtered to obtain a first filtered signal, the first filtered signal is an AC signal, the first filtered signal is obtained by the second signal amplifying unit to obtain the second conditioned signal, the second conditioned signal is used to detect the magnitude of the measured current under a small output range, and the output voltage of the second conditioned signal is used to determine whether there is an arcing current in the circuit under test.

[0027] The present invention also provides a power supply device, which includes the above-mentioned detection circuit and power supply circuit.

[0028] The technical solution of the present invention has the following advantages:

[0029] 1. The current sensor provided by the present invention comprises: a current conductor, a magnetic sensor structure, a first signal amplification unit and a second signal amplification unit. The current conductor is suitable for connecting to a current port to be measured to access the current to be measured; the magnetic sensor structure is configured to be above the current conductor, and the magnetic sensor structure is used to sense the magnetic signal generated by the current to be measured and form an electrical signal; the first signal amplification unit is used to receive the electrical signal output by the magnetic sensor structure, and amplify the electrical signal once to form a first conditioned signal; the second signal amplification unit is used to receive a first filtered signal and amplify the first filtered signal twice to form a second conditioned signal; the first filtered signal is a signal obtained after an external first auxiliary circuit receives the first conditioned signal and processes the first conditioned signal; the first conditioned signal and the second conditioned signal are used to characterize the magnitude of the current to be measured under different ranges.

[0030] The current sensor of this structure uses a magnetic sensor structure to sense the current of the current conductor. The first signal amplification unit amplifies the output electrical signal of the magnetic sensor structure once, and the second signal amplification unit amplifies the first filtered signal twice. The first signal amplification unit and the second signal amplification unit are dual-core structures. The first conditioned signal obtained by the first signal amplification unit after amplifying the electrical signal once can represent the magnitude of a large-scale current. The second conditioned signal obtained by the second signal amplification unit after amplifying the first filtered signal twice can represent the magnitude of a small-scale current, thereby realizing dual-range measurement of large and small currents. The current sensor is widely applicable and is suitable for current detection in compact power electronic systems. At the same time, in conjunction with an external auxiliary circuit, the current sensor of this structure can realize DC arc detection and AC arc detection in the photovoltaic field.

[0031] 2. The current sensor provided by the present invention has a magnetic sensor structure including at least one magnetic sensor chip, which is used to sense the magnetic signal generated by the measured current through a magnetic sensing element and convert the magnetic signal into an electrical signal; wherein the magnetic sensor structure includes a first magnetic sensor chip and a second magnetic sensor chip, the first magnetic sensor chip includes a first magnetic resistor and a third magnetic resistor, the second magnetic sensor chip includes a second magnetic resistor and a fourth magnetic resistor, the first magnetic resistor, the second magnetic resistor, the third magnetic resistor and the fourth magnetic resistor are constructed as a full-bridge circuit, thereby realizing a gradient full-bridge solution with strong anti-interference ability.

[0032] 3. In the current sensor provided by the present invention, the first signal amplification unit and the second signal amplification unit are programmable operational amplifiers. The programmable operational amplifier includes: at least two operational amplifiers, a decoder module and a resistor switch array module connected to each other. The multiple operational amplifiers connected to each other are used to amplify the electrical signal or the first conditioned signal step by step. The decoding result output by the decoder module controls the attenuation amount of the input signal by the resistor switch array module, thereby finally realizing the programmability of the amplifier gain.

[0033] 4. The current detection circuit provided by the present invention, the first auxiliary circuit includes a filter circuit, the filter circuit is used to filter the interference signal of the first conditioned signal to obtain a first filtered signal; the second auxiliary circuit includes a filter circuit, the filter circuit is used to filter the interference signal of the second conditioned signal to obtain a second filtered signal. Based on the acquired first conditioned signal, some interference signals in the circuit can be filtered out through the first auxiliary circuit, and voltage spikes in the circuit can be absorbed. After the buffer circuit signal enters the input side of the second signal amplification unit, the second conditioned signal after secondary amplification is filtered to reduce the influence of the interference signal on the actual output result.

[0034] 5. The current detection circuit provided by the present invention, the first auxiliary circuit includes a first resistor, the first signal amplification unit outputs a first conditioning signal, the first conditioning signal is used to detect the magnitude of the measured current under a large output range, the first conditioning signal is processed by the first resistor to obtain a first filtering signal, the first filtering signal is processed by the second signal amplification unit to obtain the second conditioning signal, the second conditioning signal is used to detect the magnitude of the current under a small range; or, the first auxiliary circuit includes a first capacitor, the first signal amplification unit outputs a first conditioning signal, the first conditioning signal is used to detect the magnitude of the measured current under a large output range, the first conditioning signal is processed by the first capacitor and filtered to obtain the first filtering signal, the first filtering signal is an AC signal, the first filtering signal is processed by the second signal amplification unit to obtain the second conditioning signal, the second conditioning signal is used to detect the magnitude of the current under a small range, and the output voltage of the second conditioning signal is used to determine whether there is an arc current in the circuit under test. By detecting the arc current, it is possible to determine whether there is an arc current in the current, and to achieve DC arc detection and AC arc detection in the photovoltaic field. When photovoltaic inverter panels are used outdoors for a long time, cable aging and poor contact may occur, which may cause arcing during normal use. In severe cases, high-temperature fires may occur, posing a major safety hazard. Arc detection can promptly discover and eliminate safety hazards, effectively avoiding the occurrence of the above safety hazards. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0036] Figure 1 A schematic diagram of the structure of the current sensor in Example 1 provided by the present invention;

[0037] Figure 2 A schematic diagram of the electrical connection of four magnetic resistors in the current sensor in Example 1 provided by the present invention;

[0038] Figure 3 A schematic diagram of a programmable operational amplifier in a current sensor in Embodiment 1 provided by the present invention;

[0039] Figure 4 A detection schematic diagram of a current detection circuit in Embodiment 2 provided by the present invention;

[0040] Figure 5 A detection schematic diagram of another current detection circuit in Embodiment 2 provided by the present invention;

[0041] Reference numerals:

[0042] 1- Current conductor;

[0043] 2-Magnetic sensor structure;

[0044] 21-first magnetic sensor chip; 211-first magnetic resistor; 212-third magnetic resistor;

[0045] 22 - second magnetic sensor chip; 221 - second magnetic resistor; 222 - fourth magnetic resistor; 23 - first port; 24 - second port; 25 - first output terminal; 26 - second output terminal;

[0046] 31-first signal amplifying unit; 32-second signal amplifying unit; 33-operational amplifier; 34-decoder module; 35-resistance switch array module;

[0047] 4-Frame structure. DETAILED DESCRIPTION

[0048] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0050] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, it can also be the internal connection of two components, it can be a wireless connection, or it can be a wired connection. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0051] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0052] Example 1

[0053] This embodiment provides a current sensor such as Figures 1 to 3 As shown, it includes: a current conductor 1, a magnetic sensor structure 2, a first signal amplification unit 31 and a second signal amplification unit 32. Among them, the current conductor 1 is suitable for connecting to the measured current port to access the measured current, the magnetic sensor structure 2 is configured to be above the current conductor 1, and the magnetic sensor structure 2 is used to sense the magnetic signal generated by the measured current and form an electrical signal; the first signal amplification unit 31 and the second signal amplification unit 32 are both used to amplify the signal input from their input end side, and output after amplification, wherein the first signal amplification unit 31 is used to receive the electrical signal output from the magnetic sensor structure 2 side, and amplify the electrical signal once to form a first conditioned signal, and the second signal amplification unit is used to receive the first filtered signal and amplify the first filtered signal twice to form a second conditioned signal; wherein the first filtered signal is a signal obtained after the external first auxiliary circuit receives the first conditioned signal and processes the first conditioned signal; the first conditioned signal and the second conditioned signal are respectively used to characterize the magnitude of the measured current under different ranges. Generally speaking, the first signal amplification unit 31 is used to indicate the magnitude of the current under a large range, and the second signal amplification unit 32 is used to indicate the magnitude of the current under a small range.

[0054] As shown Figure 1 in FIG. 1, the current-carrying wire 1 includes a first arm and a second arm, and the current flowing through the first arm is opposite to that flowing through the second arm; specifically, in the current sensor provided in this embodiment, the current-carrying wire 1 is a U-shaped current-carrying wire, and the first arm and the second arm are respectively two arms of the U-shaped current-carrying wire. The current to be detected flows into the current-carrying wire 1 from the first arm and flows out from the second arm. In other alternative embodiments, the shape of the current guide can be V-shaped or U-shaped, as long as it is ensured that the flow directions of the currents flowing through the first arm and the second arm are different.

[0055] As shown Figure 1 in FIG. 2, the magnetic sensor structure 2 includes a first magnetic sensor chip 21 and a second magnetic sensor chip 22. Each magnetic sensor chip, when a measured current is passed through the current-carrying wire, senses the magnetic signal generated by the measured current through a magnetic sensing element and converts the magnetic signal into an electrical signal. In this embodiment, the first magnetic sensor chip 21 is disposed on the first arm, and the second magnetic sensor chip 22 is disposed on the second arm. The first magnetic sensor chip 21 and the second magnetic sensor chip 22 are symmetrically disposed with respect to the U-shaped current-carrying wire. Generally speaking, the number of magnetic sensor chips provided is an even number. Therefore, in other alternative embodiments, the number of magnetic sensor chips can be four, six, eight or more, as long as the magnetic sensor chips can be symmetrically disposed on both sides of the U-shaped wire.

[0056] Specifically, in this embodiment, the first magnetic sensor chip 21 includes a first magnetoresistor 211 and a third magnetoresistor 212, and the second magnetic sensor chip 22 includes a second magnetoresistor 221 and a fourth magnetoresistor 222. It should be noted that Figure 1 the specific positions of the respective magnetoresistors shown in FIG. 3 are only for illustration, and the actual installation positions of the magnetoresistors on each chip can be adjusted and changed according to the usage requirements.

[0057] In this embodiment, the first magnetoresistor 211, the second magnetoresistor 221, the third magnetoresistor 212, and the fourth magnetoresistor 222 have the same physical properties and the same magnetic field sensitive directions. Since a magnetic field is generated around the current-carrying wire 1 through which the measured current is passed, the magnetic fields generated at the two arms of the U-shaped current-carrying wire act on the first magnetoresistor 211, the second magnetoresistor 221, the third magnetoresistor 212, and the fourth magnetoresistor 222 respectively, thereby causing the resistance values of the four magnetoresistors to change, and further generating an output voltage (i.e., an electrical signal), thereby implementing a gradient full-bridge scheme with strong anti-interference ability.

[0058] As shown Figure 2The figure shows the electrical connection diagram of four magnetic resistors, wherein the first magnetic resistor 211, the second magnetic resistor 221, the third magnetic resistor 212 and the fourth magnetic resistor 222 together form a full-bridge electrical bridge structure. A driving voltage is applied between the first port 23 and the second port 24, and the first output port 25 and the second output port 26 are output ports. Since the resistance of the magnetic resistor changes with the external magnetic field, and the currents of the two arms of the U-shaped current conductor are in opposite directions and have equal values, the resistance of the first magnetic resistor 211 and the second magnetic resistor 221 change in opposite directions, and the resistance of the third magnetic resistor 212 and the fourth magnetic resistor 222 also change in opposite directions. At the same time, the resistance of the first magnetic resistor 211 and the third magnetic resistor 212 of the first magnetic sensor chip 21 on the left side wall change in the same manner, and the resistance of the second magnetic resistor 221 and the fourth magnetic resistor 222 of the second magnetic sensor chip 22 on the right side wall change in the same manner. Therefore, an output voltage is generated between the two output ports of the electrical bridge. The magnetoresistance is an anisotropic resistance element, a giant magnetoresistance element or a magnetic tunnel junction element, and the giant magnetoresistance element or the magnetic tunnel junction element can be a multilayer film structure with a nanometer thickness, so that the current sensor is small in size and has high sensitivity, which also greatly reduces the cost. In this embodiment, the magnetic sensing element specifically adopts a TMR tunnel magnetoresistance element.

[0059] In other optional implementations, only one magnetic resistor is provided on each magnetic sensor chip. In this case, two magnetic resistors can form a half-bridge bridge structure, which also meets the requirement of strong anti-interference capability.

[0060] In this embodiment, the first signal amplifying unit 31 and the second signal amplifying unit 32 are programmable operational amplifiers. Figure 3As shown, the programmable operational amplifier includes: at least two operational amplifiers 33 connected to each other, a decoder module 34 and a resistor switch array module 35. For the first signal amplification unit 31, the multiple operational amplifiers 33 connected in the first signal amplification unit 31 are used to amplify the electrical signal step by step to form a first conditioned signal. For the second signal amplification unit 32, the multiple operational amplifiers connected in the second signal amplification unit 32 amplify the first filtered signal step by step to form a second conditioned signal, and then the attenuation of the input signal is controlled by the resistor switch array module 35 through the decoding results output by the decoder module 34, and finally the gain of the amplifier is programmable. Specifically in this embodiment, three operational amplifiers are used, the gain DAC is used to set the power supply parameters of the magnetic sensor structure 2, and the Zero DAC is used to configure the product parameters. The first output terminal 25 and the second output terminal 26 of the full-bridge circuit are electrically connected to the VIP and VIN ports respectively. The output voltage on the magnetic sensor structure side changes with the change of the induced magnetic field. The first signal amplification unit 31 conditions the output voltage and outputs a normalized standard analog signal, such as 2.5±2V. The second signal amplifying unit 32 further amplifies the output of the first signal amplifying unit 31 by setting different amplification proportional coefficients, thereby achieving dual-range output.

[0061] In this embodiment, the current sensor as a whole adopts a standard SOIC16 package. Of course, other packaging methods can also be used for packaging in other optional embodiments. The current sensor also includes a base frame structure 4, which includes a substrate and a frame. The first signal amplification unit 31, the second signal amplification unit 32 and the magnetic sensor structure 2 are arranged on the substrate, and the substrate is arranged on the frame. The frame and the substrate are integrally formed or detachably connected. The specific forming method can be selected according to actual use requirements. And in the case where the first signal amplification unit 31 and the second signal amplification unit 32 use programmable operational amplifiers, it can also be flexibly adapted according to the client's usage, and has a wide range of applicability.

[0062] The current sensor further includes: wire pins arranged at the edge of the substrate, and each end of each current wire 1 is connected to one or more wire pins. Specifically, one end of the current wire can be connected to one wire pin, or of course, multiple wire pins can be connected, as long as the wire pin can guide the current to the current wire side.

[0063] In the current sensor provided in the present embodiment, the magnetic sensor structure 2 realizes current sensing for the current conductor 1, the first signal amplification unit 31 realizes primary amplification of the electrical signal output by the magnetic sensor structure 2, and the second signal amplification unit 32 realizes secondary amplification of the first filtered signal. The first signal amplification unit 31 and the second signal amplification unit 32 are dual-core structures. The first conditioned signal obtained by the first signal amplification unit 31 after primary amplification of the electrical signal can characterize the magnitude of a large-scale current, and the second conditioned signal obtained by the second signal amplification unit 32 after secondary amplification of the first filtered signal can characterize the magnitude of a small-scale current, thereby realizing dual-range measurement of large current and small current. The current sensor is widely applicable and is suitable for current detection in compact power electronic systems. At the same time, in conjunction with an external auxiliary circuit, the current sensor of this structure can realize DC arc detection and AC arc detection in the photovoltaic field.

[0064] Example 2

[0065] In the present embodiment, a current detection circuit is provided, including the current sensor provided in Embodiment 1, a first auxiliary circuit and a second auxiliary circuit; wherein the first auxiliary circuit is arranged between the first signal amplifying unit 31 and the second signal amplifying unit 32, and the first auxiliary circuit is used to receive the first conditioned signal, reduce the noise of the first conditioned signal, obtain a first filtered signal, and output it to the second signal amplifying unit 32 side; the second auxiliary circuit is arranged on the output end side of the second signal amplifying unit 32, and is used to reduce the noise of the second conditioned signal, and obtain a second filtered signal.

[0066] The first auxiliary circuit includes a filter circuit, which is used to filter the interference signal of the first conditioned signal to obtain a first filtered signal; the second auxiliary circuit includes a filter circuit, which is used to filter the interference signal of the second conditioned signal to obtain a second filtered signal; specifically, the filter circuit can be composed of a single structure of a resistance structure and a capacitance structure or a combination of the two.

[0067] The current detection circuit provided in this embodiment can filter out some interference signals in the circuit based on the acquired first conditioned signal through the first auxiliary circuit, absorb voltage spikes in the circuit, buffer the circuit signal and then enter the input side of the second signal amplification unit, and filter the second conditioned signal after secondary amplification to reduce the influence of the interference signal on the actual output result.

[0068] like Figure 3It is a specific detection method for the current detection circuit: in this embodiment, the first auxiliary circuit is the first resistor, the current sensor is a dual-core output sensor, and the two outputs are Vout1 and Vout2, respectively, wherein Vout1 is the first conditioning signal, Vout2 is the second conditioning signal, and Vout2 can detect tiny arcing signals in AC and DC circuits; PGA1 corresponds to the first signal amplification unit 31, and PGA2 corresponds to the second signal amplification unit 32. The first signal amplification unit 31 and the second signal amplification unit 32 can set different amplification factors of the product according to needs; the TMR signal is the electrical signal output by the magnetic sensor structure 2.

[0069] The specific measurement method is as follows: after the magnetic sensor structure 2 inside the current sensor detects the magnetic field generated by the current through the tunnel magnetoresistance effect, the electrical signal is transmitted to the first signal amplification unit 31, and after one amplification by the first signal amplification unit 31, Vout1 is output. Vout1 can be used to detect a large range of AC and DC signals; at the same time, the Vout1 signal can be processed by the first resistor in the external auxiliary circuit and then return to the current sensor to enter the input end of the second signal amplification unit 32 for secondary amplification, and Vout2 is output from the output side of the second signal amplification unit 32. Vout2 can be used to detect small range AC and DC signals. The programmable amplifier can set different amplification factors of the product according to needs. For example, the amplified parameter corresponding to PGA1 is 2.5V±2V@20A, where 20A is the product current range, 2V is the gain corresponding to the product at 20A full scale, and PGA2 sets the amplification factor to 10 times. After the signal is amplified by PGA2, it is 2.5V±2V@2A, that is, the full scale corresponds to 2A. At this time, the current sensor can detect 20A current signals and detect small current signals of 2A; it is worth noting that the full-scale output voltage of the current sensor is 2.5V+2V (positive gain) or 2.5V-2V (negative gain).

[0070] like Figure 4 It is another specific detection method for the current detection circuit: in this embodiment, the first auxiliary circuit is a capacitor, the current sensor is a dual-core output sensor, and the two outputs are Vout3 and Vout4, respectively, wherein Vout3 is the corresponding first conditioning signal, Vout4 is the corresponding second conditioning signal, and Vout4 can detect tiny arcing signals in AC and DC circuits; PGA1 corresponds to the first signal amplification unit 31, and PGA2 corresponds to the second signal amplification unit 32. The first signal amplification unit 31 and the second signal amplification unit 32 can set different amplification factors of the product according to needs; the TMR signal is the electrical signal output by the magnetic sensor structure 2.

[0071] The specific measurement method is as follows: after the magnetic sensor structure 2 inside the current sensor detects the current through the tunnel magnetoresistance effect, the electrical signal is transmitted to the first signal amplification unit 31, and after being amplified once by the first signal amplification unit 31, Vout3 is output. Vout3 can be used to detect a large range of AC and DC signals; at the same time, the Vout3 signal can be processed by an external capacitor in an external auxiliary circuit to filter out the DC signal to form a first filtered signal, and then returned to the current sensor. The first filtered signal enters the input end of the second signal amplification unit 32 for secondary amplification, and Vout4 is output from the output side of the second signal amplification unit. Vout4 can be used to detect a small range of AC signals. The programmable amplifier can set different magnifications of the product according to the needs. For example, the amplified parameter corresponding to PGA1 is 2.5V±2V@20A, that is, the full scale is 20A. The amplification factor of PGA2 is set to 100 times. After the signal is amplified by PGA2, it is 2.5V±2V@0.2A, that is, the full scale corresponds to 0.2A. At this time, the current sensor can detect 20A current signals and detect small current signals of 0.2A. It is worth noting that the full-scale output of the current sensor should be 2.5V+2V (positive gain) or 2.5V-2V (negative gain).

[0072] In this example, if the measured current is DC 20A+AC 0.2A, where AC 0.2A is the arc current, then Figure 5 After the current detection circuit shown in the figure, when the current to be measured passes through the first conditioning signal and then passes through the capacitor, it is filtered, that is, DC 20A is filtered. Therefore, the first filtered signal output from the capacitor side is only the arc current of AC 0.2A. Therefore, the current to be measured passes through the capacitor. Figure 5 After the current detection circuit shown in , after the AC signal 0.2A passes through PGA21 and PGA2, the full-scale voltage output of Vout4 is 2.5V+2V (positive gain) or 2.5V-2V (negative gain), thereby realizing the detection of arc current. By detecting the arc current, it is possible to determine whether there is an arc current in the current, and to realize DC arc detection and AC arc detection in the photovoltaic field, thereby reducing the probability of dangerous events. When the photovoltaic inverter panel is used outdoors for a long time, the cable will age and the contact will be poor, so that arcs may occur during normal use. In severe cases, high-temperature fires may occur, which poses a great safety hazard. Arc detection can promptly discover and eliminate safety hazards, effectively avoiding the occurrence of the above safety hazards.

[0073] Example 3

[0074] This embodiment provides a power supply device, including the detection circuit and power supply circuit provided in Embodiment 2.

[0075] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A current sensor, characterized in that: include: A current conductor (1), wherein the current conductor (1) is suitable for being connected to a current port to be measured so as to receive the current to be measured; A magnetic sensor structure (2) is configured to be above the current conductor (1), and the magnetic sensor structure (2) is used to sense the magnetic signal generated by the measured current and form an electrical signal; A first signal amplifying unit (31) is used to receive the electrical signal output by the magnetic sensor structure (2), and amplify the electrical signal once to form a first conditioned signal; A second signal amplifying unit (32) is used to receive a first filtered signal and amplify the first filtered signal twice to form a second conditioned signal; wherein the first filtered signal is a signal obtained after an external first auxiliary circuit receives the first conditioned signal and processes the first conditioned signal, wherein the first conditioned signal and the second conditioned signal are respectively used to characterize the magnitude of the measured current under different ranges, and the current sensor is suitable for detecting the arc current generated in the photovoltaic inverter; The first auxiliary circuit is arranged between the first signal amplifying unit (31) and the second signal amplifying unit (32), and is used for receiving the first conditioned signal, reducing noise on the first conditioned signal, obtaining a first filtered signal, and outputting the first filtered signal to the second signal amplifying unit (32); The first auxiliary circuit includes a filter circuit, and the filter circuit is used to filter the interference signal of the first conditioned signal to obtain the first filtered signal; The first auxiliary circuit comprises a first capacitor, the first signal amplifying unit (31) outputs a first conditioned signal, the first conditioned signal is used to detect the magnitude of the current to be measured under a large output range, the first conditioned signal is processed by the first capacitor and then filtered to obtain a first filtered signal, the first filtered signal is an AC signal, the first filtered signal is passed through a second signal amplifying unit (32) to obtain the second conditioned signal, the second conditioned signal is used to detect the magnitude of the current to be measured under a small output range, and the output voltage of the second conditioned signal is used to determine whether an arc current exists in the circuit to be measured; The current sensor is a dual-core output sensor, and the two outputs are Vout3 and Vout4, wherein the electrical signal is amplified once by the first signal amplification unit and output as Vout3, and the first filtered signal is amplified twice by the second signal amplification unit and output as Vout4.

2. The current sensor according to claim 1, characterized in that: The current conductor includes a first arm and a second arm, and the current flowing through the first arm is opposite to the current flowing through the second arm; The magnetic sensor structure (2) comprises a first magnetic sensor chip (21) and a second magnetic sensor chip (22), wherein the magnetic sensor chip is used to sense a magnetic signal generated by a measured current through a magnetic sensing element and convert the magnetic signal into an electrical signal, wherein the first magnetic sensor chip (21) is arranged on the first arm, and the second magnetic sensor chip (22) is arranged on the second arm.

3. The current sensor according to claim 2, characterized in that: The first magnetic sensor chip (21) comprises a first magnetic resistor (211) and a third magnetic resistor (212), and the second magnetic sensor chip (22) comprises a second magnetic resistor (221) and a fourth magnetic resistor (222); The first magnetoresistance (211), the second magnetoresistance (221), the third magnetoresistance (212) and the fourth magnetoresistance (222) are constructed as a full-bridge bridge circuit.

4. The current sensor according to claim 1, characterized in that: The first signal amplifying unit and the second signal amplifying unit are programmable operational amplifiers.

5. The current sensor according to claim 4, characterized in that: The programmable operational amplifier comprises: at least two operational amplifiers (33) connected to each other, a decoder module (34) and a resistor switch array module (35); the plurality of operational amplifiers (33) connected to each other are used to amplify the electrical signal or the first filtered signal step by step; and the attenuation amount of the input signal attenuated by the resistor switch array module (35) is controlled by the decoding result output by the decoder module (34).

6. The current sensor according to any one of claims 1 to 5, characterized in that: The invention also comprises a base frame structure (4), wherein the base frame structure (4) comprises a substrate and a frame, wherein the first signal amplification unit (31), the second signal amplification unit (32) and the magnetic sensor structure (2) are arranged on the substrate, and the substrate is arranged on the frame, and the frame and the substrate are integrally formed or detachably connected.

7. The current sensor according to claim 6, characterized in that: It also comprises: wire pins arranged at the edge of the substrate, and each end of each current wire (1) is respectively connected to one or more of the wire pins.

8. A current detection circuit, characterized in that: The current sensor, the first auxiliary circuit and the second auxiliary circuit according to any one of claims 1 to 7; The second auxiliary circuit is arranged at the output end side of the second signal amplifying unit (32) and is used to obtain a second filtered signal after reducing the noise of the second conditioned signal.

9. The current detection circuit according to claim 8, characterized in that: The second auxiliary circuit includes a filter circuit, and the filter circuit is used to filter the interference signal of the second conditioned signal to obtain the second filtered signal.

10. A power supply device, characterized in that: The power supply device comprises the detection circuit and the power supply circuit described in claim 8 or 9.

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