CN112630502A - Sensor capable of simultaneously detecting direct current and arc discharge current - Google Patents

Sensor capable of simultaneously detecting direct current and arc discharge current Download PDF

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Publication number
CN112630502A
CN112630502A CN202011596871.6A CN202011596871A CN112630502A CN 112630502 A CN112630502 A CN 112630502A CN 202011596871 A CN202011596871 A CN 202011596871A CN 112630502 A CN112630502 A CN 112630502A
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China
Prior art keywords
inductor
chip
connecting end
current
capacitor
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朱海华
周耀
谢建勇
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Ningbo Sinomags Electronic Technology Co ltd
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Ningbo Sinomags Electronic Technology Co ltd
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Priority to CN202011596871.6A priority Critical patent/CN112630502A/en
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
    • G01R19/0092—Arrangements for measuring currents or voltages or for indicating presence or sign thereof measuring current only
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
    • G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
    • G01R15/20—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using galvano-magnetic devices, e.g. Hall-effect devices, i.e. measuring a magnetic field via the interaction between a current and a magnetic field, e.g. magneto resistive or Hall effect devices
    • G01R15/202—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks using galvano-magnetic devices, e.g. Hall-effect devices, i.e. measuring a magnetic field via the interaction between a current and a magnetic field, e.g. magneto resistive or Hall effect devices using Hall-effect devices

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  • General Physics & Mathematics (AREA)
  • Measuring Instrument Details And Bridges, And Automatic Balancing Devices (AREA)

Abstract

The application discloses can detect direct current and draw sensor of arc current simultaneously includes: the shell comprises an inner wall and an outer wall, and a gap is formed between the inner wall and the outer wall; the magnetic core is positioned in the gap, and a gap with a preset size is designed on the preset side wall in an open-loop mode; the PCB comprises a first part and a second part, the second part is connected with the first part, the second part is embedded between two side walls of the gap, and the first part is positioned on the outer side of the magnetic core and is abutted against the side face where the gap is positioned; the direct current detection chip is attached to the first surface of the second part; the arc discharge current detection chip is attached to the second surface of the second part; the signal processing module is respectively connected with the direct current detection chip and the arc discharge current detection chip, and is used for processing and outputting the detected direct current signal and the detected arc discharge current signal; this scheme can detect direct current and draw the arc current simultaneously, and small, does benefit to board and carries the installation.

Description

Sensor capable of simultaneously detecting direct current and arc discharge current
Technical Field
The application relates to the field of group string current and arc discharge current detection equipment, in particular to a sensor capable of simultaneously detecting direct current and arc discharge current.
Background
The photovoltaic inverter panel is when outdoor live time is longer, phenomena such as cable ageing, contact failure can appear to electric arc can appear in normal use, can appear high temperature when serious and catch fire, have great potential safety hazard, detect through drawing the arc and can in time discover and remove the potential safety hazard, effectively avoided the emergence of above-mentioned potential safety hazard, consequently, draw the arc to the photovoltaic inverter panel and detect and become a current mainstream trend. In addition to detecting the arcing current, direct current signal detection is also essential.
The detection principle of the arc detection device in the prior art is similar to the application of a transformer, and as shown in fig. 1, a large primary side current of the transformer is converted into a small secondary side current according to the electromagnetic induction principle, the current induced by a secondary winding is sampled by a series resistor and then sent to a signal processing module, and the signal processing module restores the original current through the rated mutual inductance ratio of the transformer. The mutual inductance ratio of the transformer is the ratio of rated currents of the primary side primary winding N1 and the secondary side secondary winding N2, or can be approximately expressed as the turn ratio of a primary side primary winding coil and a secondary side secondary winding coil, and the secondary side is arranged in a closed magnetic ring.
The device diagram of the detection device adopted by the direct current detection part is shown in fig. 2a, the circuit diagram is shown in fig. 2b, the primary current passes through the magnetic ring, the magnetic ring generates a magnetic field according to electromagnetic induction, and the sensing chips in the gaps of the magnetic ring are converted into voltage signals according to the induced magnetic field and output so as to facilitate subsequent detection.
In the prior art, the device for detecting the direct current and the device for detecting the arcing current are independent devices, so that the technical problems of large volume and inconvenience for onboard installation are caused.
Therefore, a detection device which has a small size and can simultaneously realize arc discharge current detection and direct current detection is lacked in the prior art.
Content of application
Therefore, in order to solve the technical problem that a detection device which has a small size and can simultaneously realize arc discharge current detection and direct current detection is absent in the prior art scheme, the application provides a sensor capable of simultaneously detecting direct current and arc discharge current.
According to the sensor that this application embodiment provided can detect direct current and draw arc current simultaneously, include:
the shell comprises an inner wall and an outer wall, and a gap is formed between the inner wall and the outer wall;
the magnetic core is positioned in the gap, and a gap with a preset size is designed on the preset side wall in an open-loop mode;
the PCB comprises a first part and a second part, the second part is connected with the first part, the second part is embedded between two side walls of the gap, and the first part is positioned on the outer side of the magnetic core and is abutted against the side face where the gap is positioned;
the direct current detection chip is attached to the first surface of the second part and used for detecting direct current;
the arc discharge current detection chip is attached to the second surface of the second part and used for detecting arc discharge current;
the signal processing module is respectively connected with the direct current detection chip and the arc discharge current detection chip, and is used for processing and outputting the detected direct current signal and the detected arc discharge current signal;
wherein the second surface is opposite the first surface.
Preferably, the side wall of the gap is provided with a first flange protruding outwards, a first recess matched with the first flange is arranged at a corresponding position of the first part of the PCB, and the first part of the PCB is tightly attached to the preset side wall by matching the first flange with the first recess.
Preferably, a fixing piece is arranged on one side of the inner wall close to the gap of the magnetic core,
the fixing piece is abutted to the preset side edges of the two side walls of the gap and used for fixing the magnetic core.
Preferably, the fixing member includes a first fixing plate and a second fixing plate, and the first fixing plate and the second fixing plate are respectively abutted to the side walls on both sides of the gap.
Preferably, the direct current detection chip and the arc discharge current detection chip are all full-bridge chips.
Preferably, in the processing module, a circuit structure of a processing unit corresponding to the dc current detecting chip includes:
the first magnetic sensing chip is composed of a first inductor, a second inductor, a third inductor and a fourth inductor;
the first filtering module comprises a fifth inductor and a sixth inductor and is used for filtering alternating current;
the first operational amplifier comprises a first connecting end, a second connecting end, a third connecting end, a fourth connecting end and a grounding end, the third connecting end is connected with a fifth inductor, the second connecting end is connected with a sixth inductor, a second capacitor and a seventh inductor which are connected in parallel are arranged between the first connecting end and the second connecting end, an eighth inductor and a first capacitor which are connected in parallel are arranged between the fifth inductor and the third connecting end, and the fourth connecting end is an output end;
the first inductor and the second inductor are connected in series to form a first inductor group, the third inductor and the fourth inductor are connected in series to form a second inductor group, and the first inductor group and the second inductor group are connected in parallel to form the first magnetic sensing chip; and
the capacitance value of the first capacitor is the same as that of the second capacitor, and the resistance value of the seventh inductor is the same as that of the eighth inductor.
Preferably, the first and second electrodes are formed of a metal,
the low-pass frequencies of the first capacitor and the second capacitor are both f1＝1/(2*PI*C1*R7)；
Wherein, C1Is the capacitance value, R, of the first capacitor C17Is the resistance value of the seventh inductor MR1, and PI is the circumferential value.
Preferably, the sensitivity of the first magnetic sensing chip is 0.1mV/V/Gs-0.5 mV/V/Gs.
Preferably, the output voltage V of the dc current detecting chipout1Comprises the following steps:
Vout1＝β1*I1*Sen1*M1+Vref1；
wherein, beta1Is the amplification factor of the first magnetic sensor chip,I1is primary side current, Sen1Sensitivity of the first magnetic sensor chip, M1For magnetic fields generated per 1A DC current, Vref1Is a bias voltage of the first magnetic sensor chip.
Preferably, in the processing module, a circuit structure of the processing unit corresponding to the arc discharge current detection chip includes:
the second magnetic sensing chip is composed of a ninth inductor, a tenth inductor, an eleventh inductor and a twelfth inductor;
the second filtering module comprises a thirteenth inductor, a fourteenth inductor, a fifth capacitor and a sixth capacitor and is used for filtering direct current;
the second operational amplifier comprises a first connecting end, a second connecting end, a third connecting end, a fourth connecting end and a grounding end, the third connecting end is connected with the thirteenth inductor, the second connecting end is connected with the fourteenth inductor, a fourth capacitor and a fifteenth inductor which are connected in parallel are arranged between the first connecting end and the second connecting end, a sixteenth inductor and a third capacitor which are connected in parallel are arranged between the thirteenth inductor and the third connecting end, and the fourth connecting end is an output end;
the ninth inductor and the tenth inductor are connected in series to form a third inductor group, the eleventh inductor and the twelfth inductor are connected in series to form a fourth inductor group, and the third inductor group and the fourth inductor group are connected in parallel to form the second magnetic sensing chip; and
the resistance value of the thirteenth inductor is the same as that of the fourteenth inductor, and the resistance value of the fifteenth inductor is the same as that of the sixteenth inductor.
Preferably, the frequencies of the third capacitor and the fourth capacitor are both: f. of2＝1/(2*PI*C5*R13)；
Wherein, C5Is the capacitance value of the fifth capacitor, R13Is the resistance value of the thirteenth inductor.
Preferably, the sensitivity of the second magnetic sensing chip is 2mV/V/Gs-5 mV/V/Gs.
Preferably, the output voltage V of the arc current detection chipout2Comprises the following steps:
Vout2＝β2*I2*Sen2*M2+Vref2；
wherein, beta2Is the magnification of the second magnetic sensor chip, I2Is primary side current, Sen2Sensitivity of the first magnetic sensor chip, M2For magnetic fields generated per 1A DC current, Vref2Is a bias voltage of the second magnetic sensor chip.
Preferably, the sensor capable of detecting the direct current and the arc discharge current simultaneously further comprises:
and the fixing component comprises a bottom plate and a fixing pin fixed on one surface of the bottom plate, and is connected with one surface of the first part of the PCB through the other surface of the bottom plate.
The application can achieve the following technical effects:
1. the magnetic core is designed to be open-loop to preset a gap, so that the saturation of the magnetic core is improved, the arc discharge current induction device can still sense alternating current type arc discharge current when sensing larger direct current, and the arc discharge current induction device is effectively guaranteed to have higher induction capability.
2. The sensor capable of simultaneously detecting the direct current and the arc discharge current overcomes the defect that a device capable of simultaneously detecting the direct current and the arc discharge current does not exist in the prior art; in addition, the direct current detection chip and the arc discharge current detection chip are respectively attached to the opposite surfaces of the second part of the PCB, so that the size of the sensor with the direct current detection capability and the arc discharge current detection capability is small, and the on-board mounting is facilitated.
3. The magnetic core has low requirement on materials, adopts ferrite, has low price, ensures lower cost and improves convenient conditions for batch production.
Drawings
In order to more clearly illustrate the detailed description of the present application or the technical solutions in the prior art, the drawings needed to be used in the detailed description of the present application or the prior art description will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative efforts.
Fig. 1 is a schematic diagram of the mechanism of a transformer in a prior art solution;
fig. 2a is a schematic diagram of a dc current detection device in a prior art solution;
FIG. 2b is a circuit diagram of the DC current detecting device in the prior art;
fig. 3 and fig. 4 are schematic diagrams of a sensor capable of detecting a direct current and an arc discharge current simultaneously according to an embodiment of the present disclosure;
fig. 5 is a circuit diagram corresponding to a dc current detecting chip in the sensor capable of simultaneously detecting dc current and arc discharge current according to the embodiment of the present disclosure;
fig. 6 is a graph illustrating a relationship between an output voltage of the dc detection chip and a change of the induced magnetic field according to the embodiment of the present disclosure;
fig. 7 is a circuit diagram corresponding to an arc discharge current detection chip in the sensor capable of simultaneously detecting a dc current and an arc discharge current according to the embodiment of the present application;
fig. 8 is a graph illustrating a relationship between an output voltage of the arc discharge current detection chip and a change of the induced magnetic field according to the embodiment of the present disclosure;
FIG. 9a is a graph showing the relationship between the output voltage of the first magnetic sensor chip and the detected DC current according to an embodiment of the present application;
fig. 9b is a graph illustrating a relationship between an output voltage of the second magnetic sensor chip and a detected arc discharge current according to an embodiment of the present application;
fig. 10 is a graph of bandwidth versus frequency of a sensor capable of detecting dc current and arc discharge current simultaneously according to an embodiment of the present disclosure.
Detailed Description
The technical solutions of the present application will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are only some embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present application. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present application, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; the two elements may be directly connected or indirectly connected through an intermediate medium, or may be communicated with each other inside the two elements, or may be wirelessly connected or wired connected. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art.
In addition, the technical features mentioned in the different embodiments of the present application described below may be combined with each other as long as they do not conflict with each other.
Example 1
The embodiment of the present application provides a sensor capable of detecting a direct current and an arc discharge current simultaneously, as shown in fig. 3 and 4, including a housing 31, a magnetic core 32, a PCB 33, a direct current detecting chip 34, an arc discharge current detecting chip 35 and a signal processing module,
the shell 31 comprises an inner wall 311 and an outer wall 312, and a gap is arranged between the inner wall 311 and the outer wall 312; the gap is used for accommodating the magnetic core;
the magnetic core 32 is positioned in the gap, and a gap 321 with a preset size is designed on the preset side wall of the magnetic core in an open loop mode;
the PCB 33 comprises a first part 331 and a second part 332, the second part 332 is connected with the first part 331, the second part 332 is embedded between two side walls of the gap 321, and the first part 331 is positioned outside the magnetic core 32 and is abutted against the side surface where the gap 321 is positioned; two side edges of the second part are respectively abutted against two side walls of the gap.
A dc current detection chip 34 attached to the first surface of the second portion 332, for detecting a dc current;
the arc discharge current detection chip 35 is attached to the second surface of the second portion 332 and used for detecting arc discharge current;
the signal processing module is respectively connected with the direct current detection chip 34 and the arc discharge current detection chip 35, and processes and outputs the detected direct current signal and the detected arc discharge current signal; it should be noted that the direct current detection chip 34 and the arcing current detection chip 35 may both adopt an SMT process, and are soldered on the PCB by solder paste, and the signal processing module may be disposed on the PCB, or the processing unit corresponding to the direct current detection chip 34 may be disposed on the direct current detection chip, and the processing unit corresponding to the arcing current detection chip 35 is disposed on the arcing current detection chip.
Wherein the second surface is opposite the first surface.
In the embodiment of the present invention, the specific size of the preset gap designed in an open-loop manner on the preset side wall is positively correlated with the dc saturation current of the magnetic core, that is, if the dc saturation current of the magnetic core needs to be large, the size of the gap designed in the open-loop manner should be correspondingly large, so that the magnetic core still has the capability of inducing an ac arc discharge current when inducing a large dc current.
In this application embodiment, open loop design has the gap of default size on the predetermined lateral wall of magnetic core, and closed loop design in traditional scheme, the technical scheme that open loop design has the gap of default size has improved the saturation of magnetic core to make the sensor also not so easily saturate even have under the circumstances of direct current, can effectively output the arc current that draws that detects.
The magnetic core in the embodiment of the application, can adopt the ferrite material, compare in the technical scheme that adopts the great nanometer magnetic ring in saturation field to improve the saturation field of magnetic core, this scheme is low to the requirement of material, low price, the volume of being convenient for, it is more important, the magnetic core that has the gap of predetermineeing the size of adopting the ferrite material preparation adopts the nanometer magnetic core than, under the same circumstances in saturation field, the volume that has the magnetic core in the gap of predetermineeing the size of adopting the ferrite material preparation is less than the volume that adopts the closed magnetic core of nanometer material preparation far away, therefore, can effectively guarantee the less volume of sensor, very big convenient condition is provided for on-board installation.
In the embodiment of the present application, the material of the housing is not specifically limited, and may be modified according to actual requirements.
In this application embodiment, with direct current detection chip 34 and draw the relative surface of arc current detection chip 35 laminating at the second portion that is located the gap to can reach the sensor and can detect direct current and draw the purpose of arc current simultaneously, the volume of the sensor of having effectively guaranteed this scheme and providing is less, provides convenient condition for board carries the installation.
In this application embodiment, the lateral wall in gap is provided with outside bellied first flange, the relevant position department of the first part of PCB board be provided with the first sunken of first flange matching, through first flange and first sunken matching make the first part of PCB board with predetermine the lateral wall and closely laminate.
In the embodiment of the application, a fixing piece is arranged on one side of the inner wall close to the gap of the magnetic core,
the fixing piece is abutted to the preset side edges of the two side walls of the gap and used for fixing the magnetic core.
In this application embodiment, the fixed part includes first fixed plate and second fixed plate, first fixed plate and second fixed plate with the lateral wall of gap both sides respectively the butt.
In the embodiment of the present application, the dc current detection chip and the arcing current detection chip are all full-bridge chips.
Further, referring to fig. 5, the circuit structure of the processing unit corresponding to the dc current detecting chip includes:
the first magnetic sensing chip 41 is composed of a first inductor MR1, a second inductor MR2, a third inductor MR3 and a fourth inductor MR 4; the first magnetic sensor chip 41 may be soldered on a PCB board; a first filtering module 42 including a fifth inductor MR5 and a sixth inductor MR6 for filtering the ac current;
the first operational amplifier 43 comprises a first connection end P1, a second connection end P2, a third connection end P3, a fourth connection end P4 and a ground end, the third connection end P3 is connected with a fifth inductor MR5, the second connection end P2 is connected with a sixth inductor MR6, a second capacitor C2 and a seventh inductor MR7 which are connected in parallel are arranged between the first connection end P1 and the second connection end P2, an eighth inductor MR8 and a first capacitor C1 which are connected in parallel are arranged between the fifth inductor MR5 and the third connection end P3, and the fourth connection end P4 is an output end; the first connection end P1, the second connection end P2, the third connection end P3, the fourth connection end P4 and the fifth connection end P5 of the first operational amplifier 43 may be soldered on a PCB, or may be integrated inside the first magnetic sensor chip, and may be set according to actual requirements.
The first inductor MR1 and the second inductor MR2 are connected in series to form a first inductor group, the third inductor MR3 and the fourth inductor MR4 are connected in series to form a second inductor group, and the first inductor group and the second inductor group are connected in parallel to form the first magnetic sensor chip 41; and
the capacitance C1 of the first capacitor is the same as the capacitance of the second capacitor C2, and the resistance of the seventh inductor MR7 is the same as the resistance of the eighth inductor MR 8.
In the embodiment of the present application, the first capacitor C1 and the second capacitor C2 are low-pass filter capacitors.
Here, a specific embodiment is described to illustrate the working process of the dc current detection chip:
the primary side current line passes through the aperture of magnetic core 32, produces magnetic field M in the gap of the default size of open-loop design on magnetic core 32, and the magnetic core is ferrite material, and direct current detects the chip and can sense magnetic field M according to the magnetic induction principle, is MR bridge type (full-bridge) magnetic sensing chip based on direct current detects the chip, and according to the change that the magnetic field that senses takes place, the resistance value that direct current detected the chip changes to, direct current detects the output voltage of chip and changes. Specifically, the relationship between the output voltage of the dc current detecting chip and the change of the induced magnetic field is shown in fig. 6. In fig. 6, the abscissa is the magnetic field strength sensed by the dc current detecting chip, and the ordinate is the output voltage of the dc current detecting chip, and it can be seen from the figure that when the magnetic field sensed by the dc current detecting chip reaches 200Gs, the output voltage of the dc current detecting chip can reach 48 mV.
Further, in the present invention,
the low-pass frequencies of the first capacitor C1 and the second capacitor C2 are both f1＝1/(2*PI*C1*L7)；
Wherein, C1C1 capacitance value of the first capacitor, L7The resistance value of the seventh inductor MR7, PI is a circumferential value.
In the embodiment of the present application, the sensitivity range of the first magnetic sensing chip composed of the first inductor MR1, the second inductor MR2, the third inductor MR3 and the fourth inductor MR4 can be 0.1mV/V/Gs-0.5mV/V/Gs, such as 0.1mV/V/Gs, 0.2mV/V/Gs, 0.3mV/V/Gs, 0.4mV/V/Gs or 0.5 mV/V/Gs. Gain beta of the first magnetic sensor chip1As a specific example of the resistance ratio of the seventh inductor MR7 to the sixth inductor MR6, the magnetic field generated by the primary current corresponds to 5Gs/A, and at the same time, the output voltage V of the DC detection chipout1Comprises the following steps:
Vout1＝β1*I1*Sen1*M1+Vref1；
wherein, beta1Is the magnification of the first magnetic sensor chip, I1Is primary side current, Sen1Sensitivity of the first magnetic sensor chip, M1For magnetic fields generated per 1A DC current, Vref1Is a bias voltage of the first magnetic sensor chip.
In this embodiment, referring to fig. 7, a circuit structure of a processing unit corresponding to the arc discharge current detection chip includes:
a second magnetic sensor chip 61 including a ninth inductor MR9, a tenth inductor MR10, an eleventh inductor MR11, and a twelfth inductor MR 12; the second magnetic sensing chip 61 may be soldered on the PCB board;
a second filtering module 62 including a thirteenth inductor MR13, a fourteenth inductor MR14, and a fifth capacitor C5And a sixth capacitor C6For filtering direct current;
a second operational amplifier 63 including a first connection end P5, a second connection end P6, a third connection end P7, a fourth connection end P8 and a ground end, wherein the third connection end P7 is connected to the thirteenth inductor MR13, the second connection end P6 is connected to the fourteenth inductor MR14, and a fourth capacitor C connected in parallel is disposed between the first connection end P5 and the second connection end P64And a fifteenth inductor MR15, a sixteenth inductor MR16 and a third capacitor C connected in parallel are arranged between the thirteenth inductor MR13 and the third connection end P73The fourth connecting end L8 is an output end; the first connection end P5, the second connection end P6, the third connection end P7, the fourth connection end P8 and the fifth connection end P5 of the second operational amplifier 63 may be soldered on a PCB, or may be integrated inside the second magnetic sensor chip 63, and may be set according to actual requirements.
The ninth inductor MR8 is connected in series with the tenth inductor MR10 to form a third inductor group, the eleventh inductor MR11 is connected in series with the twelfth inductor MR12 to form a fourth inductor group, and the third inductor group and the fourth inductor group are connected in parallel to form the second magnetic sensor chip 61; and
the resistance value of the thirteenth inductor MR13 is the same as that of the fourteenth inductor MR14, and the resistance value of the fifteenth inductor MR15 is the same as that of the sixteenth inductor MR 16.
Further, the fifth capacitor C5And a sixth capacitance C6For high-pass capacitance, the high-pass frequencies are all:
f3＝1/(2*PI*C5*L13),
the third capacitorC3And a fourth capacitance C4The frequencies of (A) are:
f2＝1/(2*PI*C2*L15)；
wherein, C5The capacitance of the fifth capacitor C5 is represented by MR13, the capacitance of the third capacitor C3 is the same as the capacitance of the fourth capacitor C4, and the capacitance of the fifth capacitor C5 is the same as the capacitance of the sixth capacitor C6.
Meanwhile, the sensitivity of the second magnetic sensing chip 61 is 2mV/V/Gs-5mV/V/Gs, such as 2mV/V/Gs, 3mV/V/Gs, 4mV/V/Gs, or 5 mV/V/Gs. The gain β of the second magnetic sensor chip 61 is a ratio of resistance values of the fifteenth inductor and the fourteenth inductor. Since the current signal is small, useful only for currents of mA level, a sensor chip of higher sensitivity is required and this second magnetic sensor chip cannot be saturated because the dc component is too large. Signals sensed by the arc discharge detection chip need to be processed through a circuit, direct current signals are filtered, and only the arc discharge signals are amplified to a rear-end detection circuit.
The arc discharge current detection chip changes the induced voltage signal with the change of the magnetic field, and specifically, a relationship diagram of the induced voltage signal and the change of the magnetic field is shown in fig. 8. In fig. 8, the abscissa represents the intensity of the induced magnetic field, and the ordinate represents the output voltage of the arc discharge current detection chip, and it can be seen from the figure that the output voltage of the arc discharge current detection chip can reach 200mV when the magnetic field induced by the arc discharge current detection chip reaches 200 Gs.
Specifically, in the embodiment of the present application, the arc discharge current detection chip operates in a range of direct current signals of about 100Gs, such as 80Gs to 110Gs, and when the arc discharge signal is superimposed on the direct current component, the arc discharge signal varies at about 100 Gs.
In the embodiment of the present application, the output voltage V of the arc current detection chipout2Comprises the following steps:
Vout2＝β2*I2*Sen2*M2+Vref2；
wherein, beta2Is amplified by the second magnetic sensing chipNumber, I2Is primary side current, Sen2Sensitivity of the second magnetic sensor chip, M2For magnetic fields generated per 1A DC current, Vref2Is the bias voltage of the second magnetic sense die. In this embodiment, I2And I1Are both primary currents, i.e. the currents in the wires passing through the first and second magnetic cores.
As follows, a specific example is illustrated:
and providing a voltage of 0.8V-1.2V, such as 1V, for the arc discharge current detection chip, and then applying a magnetic field of +/-200 Gs to detect the output of the arc discharge current detection chip in the application scene.
In this embodiment, the sensor capable of detecting dc and arcing current simultaneously further includes:
the fixing member 38 includes a base plate 381 and a plurality of fixing pins 382 fixed on one surface of the base plate, and is connected to one surface of the first portion of the PCB through the other surface of the base plate 381.
As follows, a specific embodiment of detecting the dc current and the arc discharge current by using the sensor capable of detecting the dc current and the arc discharge current simultaneously provided by the embodiments of the present application is illustrated:
setting the inversion current between 5kHz and 100kHz, simulating the primary side arc discharge current, adding 10 mA/10K Hz alternating current on the basis of 10A direct current on the primary side, and detecting the output of the direct current detection chip, which is specifically shown in FIG. 9 a. In fig. 9a, the abscissa represents the dc current value, and the ordinate represents the output of the first magnetic sensor chip of the dc current detection chip provided in the embodiment of the present application, and it can be seen from the figure that the output voltage of the first magnetic sensor chip is 4.5V when the dc current value is 25A. Note that the output voltage includes a bias voltage of the first magnetic sensor chip, and if the bias voltage of the second magnetic sensor chip is 2.5V, the actual output voltage of the first sensor chip is 2V. It should be noted that the bias voltage can be set according to actual requirements, and the magnitude of the bias voltage is not particularly limited.
Referring to fig. 9b, a graph of a relationship between the arc discharge current and the output voltage detected by the second magnetic sensor chip of the arc discharge current detection chip is shown, in fig. 9b, an abscissa represents the arc discharge current detected by the second magnetic sensor chip, and an ordinate represents the output voltage of the second magnetic sensor chip, and it can be seen from the graph that when the arc discharge current detected by the second magnetic sensor chip is 100mA, the output voltage is 4.5V.
It is pointed out that, in the embodiment of the present application, a frequency range including the frequency of the arc discharge circuit, for example, a frequency of 5KHz to 100KHz is selected, and based on this range, the output of the sensor capable of simultaneously detecting the direct current and the arc discharge current is relatively flat, and the output voltage does not change with the change of the frequency, as shown in fig. 10.
The sensor that can detect direct current and draw arc current simultaneously that this application embodiment provided, accessible fixed subassembly 38 is fixed with it to prevent to rotate or rock and lead to the phenomenon of module damages such as signal processing module to take place.
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications of this invention are intended to be covered by the scope of the invention as expressed herein.

Claims (14)

1. A sensor capable of simultaneously detecting a direct current and an arc discharge current, comprising:
the shell comprises an inner wall and an outer wall, and a gap is formed between the inner wall and the outer wall;
the magnetic core is positioned in the gap, and a gap with a preset size is designed on the preset side wall in an open-loop mode;
the PCB comprises a first part and a second part, the second part is connected with the first part, the second part is embedded between two side walls of the gap, and the first part is positioned on the outer side of the magnetic core and is abutted against the side face where the gap is positioned;
the direct current detection chip is attached to the first surface of the second part and used for detecting direct current;
the arc discharge current detection chip is attached to the second surface of the second part and used for detecting arc discharge current;
the signal processing module is respectively connected with the direct current detection chip and the arc discharge current detection chip, and is used for processing and outputting the detected direct current signal and the detected arc discharge current signal;
wherein the second surface is opposite the first surface.
2. The sensor according to claim 1, wherein the side wall of the gap is provided with a first flange protruding outward, a first recess matching with the first flange is provided at a corresponding position of the first portion of the PCB, and the first portion of the PCB is tightly attached to the predetermined side wall by matching the first flange with the first recess.
3. The sensor according to claim 1, wherein a fixing member is disposed on a side of the inner wall close to the gap of the magnetic core,
the fixing piece is abutted to the preset side edges of the two side walls of the gap and used for fixing the magnetic core.
4. The sensor according to claim 3, wherein the fixing member includes a first fixing plate and a second fixing plate, and the first fixing plate and the second fixing plate are respectively abutted against the side walls on both sides of the gap.
5. The sensor according to claim 1, wherein the dc current detecting chip and the arcing current detecting chip are all full-bridge chips.
6. The sensor according to claim 5, wherein the processing module includes a circuit structure of a processing unit corresponding to the dc current detecting chip, and the circuit structure includes:
the first magnetic sensing chip is composed of a first inductor, a second inductor, a third inductor and a fourth inductor;
the first filtering module comprises a fifth inductor and a sixth inductor and is used for filtering alternating current;
the first operational amplifier comprises a first connecting end, a second connecting end, a third connecting end, a fourth connecting end and a grounding end, the third connecting end is connected with a fifth inductor, the second connecting end is connected with a sixth inductor, a second capacitor and a seventh inductor which are connected in parallel are arranged between the first connecting end and the second connecting end, an eighth inductor and a first capacitor which are connected in parallel are arranged between the fifth inductor and the third connecting end, and the fourth connecting end is an output end;
the first inductor and the second inductor are connected in series to form a first inductor group, the third inductor and the fourth inductor are connected in series to form a second inductor group, and the first inductor group and the second inductor group are connected in parallel to form the first magnetic sensing chip; and
the capacitance value of the first capacitor is the same as that of the second capacitor, and the resistance value of the seventh inductor is the same as that of the eighth inductor.
7. The sensor of claim 6, wherein the sensor is capable of detecting both DC current and arc discharge current,
the low-pass frequencies of the first capacitor and the second capacitor are both f1＝1/(2*PI*C1*L7)；
Wherein, C1Is the capacitance value of the first capacitor, L7The resistance value of the seventh inductor, and PI is a circumference ratio value.
8. The sensor according to claim 6, wherein the sensitivity of the first magnetic sensor chip is 0.1mV/V/Gs-0.5 mV/V/Gs.
9.The sensor of claim 6, wherein the output voltage V of the DC detection chip is a voltage of a DC voltageout1Comprises the following steps:
Vout1＝β1*I1*Sen1*M1+Vref1；
wherein, beta1Is the magnification of the first magnetic sensor chip, I1Is primary side current, Sen1Sensitivity of the first magnetic sensor chip, M1For magnetic fields generated per 1A DC current, Vref1Is a bias voltage of the first magnetic sensor chip.
10. The sensor according to claim 5, wherein the processing module includes a circuit structure of a processing unit corresponding to the arc discharge current detection chip, and the circuit structure includes:
the second magnetic sensing chip is composed of a ninth inductor, a tenth inductor, an eleventh inductor and a twelfth inductor;
the second filtering module comprises a thirteenth inductor, a fourteenth inductor, a fifth capacitor and a sixth capacitor and is used for filtering direct current;
the second operational amplifier comprises a first connecting end, a second connecting end, a third connecting end, a fourth connecting end and a grounding end, the third connecting end is connected with the thirteenth inductor, the second connecting end is connected with the fourteenth inductor, a fourth capacitor and a fifteenth inductor which are connected in parallel are arranged between the first connecting end and the second connecting end, a sixteenth inductor and a third capacitor which are connected in parallel are arranged between the thirteenth inductor and the third connecting end, and the fourth connecting end is an output end;
the ninth inductor and the tenth inductor are connected in series to form a third inductor group, the eleventh inductor and the twelfth inductor are connected in series to form a fourth inductor group, and the third inductor group and the fourth inductor group are connected in parallel to form the second magnetic sensing chip; and
the resistance value of the thirteenth inductor is the same as that of the fourteenth inductor, and the resistance value of the fifteenth inductor is the same as that of the sixteenth inductor.
11. The sensor of claim 10, wherein the frequencies of the third capacitor and the fourth capacitor are both: f. of2＝1/(2*PI*C5*L13)；
Wherein, C5Is the capacitance value of the fifth capacitor, L13Is the resistance value of the thirteenth inductor.
12. The sensor of claim 10, wherein the second magnetic sensor chip has a sensitivity of 2mV/V/Gs to 5 mV/V/Gs.
13. The sensor of claim 6, wherein the output voltage V of the arcing current detecting chip is larger than the output voltage V of the arcing current detecting chipout2Comprises the following steps:
Vout2＝β2*I2*Sen2*M2+Vref2；
wherein, beta2Is the magnification of the first magnetic sensor chip, I2Is primary side current, Sen2Sensitivity of the first magnetic sensor chip, M2For magnetic fields generated per 1A DC current, Vref2Is a bias voltage of the second magnetic sensor chip.
14. The sensor capable of simultaneously detecting a direct current and an arc discharge current according to any one of claims 1 to 13, further comprising:
and the fixing component comprises a bottom plate and a fixing pin fixed on one surface of the bottom plate, and is connected with one surface of the first part of the PCB through the other surface of the bottom plate.
CN202011596871.6A 2020-12-28 2020-12-28 Sensor capable of simultaneously detecting direct current and arc discharge current Pending CN112630502A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116223885A (en) * 2023-05-08 2023-06-06 北京伽略电子股份有限公司 Current sampling circuit
CN117269584A (en) * 2023-11-21 2023-12-22 江苏多维科技有限公司 Current detection module

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116223885A (en) * 2023-05-08 2023-06-06 北京伽略电子股份有限公司 Current sampling circuit
CN117269584A (en) * 2023-11-21 2023-12-22 江苏多维科技有限公司 Current detection module
CN117269584B (en) * 2023-11-21 2024-01-30 江苏多维科技有限公司 Current detection module

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