CN214335174U

CN214335174U - Alternating current side leakage current sensor

Info

Publication number: CN214335174U
Application number: CN202023254270.5U
Authority: CN
Inventors: 朱海华; 吴越; 王建国; 姚锡刚
Original assignee: Bengbu Ximag Technology Co ltd
Current assignee: Anhui Xici Technology Co ltd
Priority date: 2020-12-29
Filing date: 2020-12-29
Publication date: 2021-10-01
Anticipated expiration: 2030-12-29

Abstract

The utility model relates to a magnetic induction field, concretely relates to exchange side leakage current sensor, include: the induction body comprises a shell with a channel and a magnetic core arranged in the shell, and an induction coil is wound on the magnetic core; the wire support wears to establish in the passageway and with the connection can be dismantled to the casing for fixed the wire that passes the passageway, the wire is including exposing the outer input and the output of wire support for connect on the three-phase alternating current line. The alternating current side leakage current sensor does not need to replace the whole alternating current side leakage current sensor, only needs to replace a wire which is damaged or does not meet the use requirement, avoids unnecessary resource waste and increases the applicability of the alternating current side leakage current sensor.

Description

Alternating current side leakage current sensor

Technical Field

The utility model relates to a magnetic induction field, concretely relates to exchange side leakage current sensor.

Background

In the application of new energy, clean energy such as solar energy and wind energy is widely applied, and the new energy also has some safety problems in the application process, such as a photovoltaic grid-connected power generation system of the solar energy. In a traditional photovoltaic grid-connected power generation system, a power frequency transformer is used for isolation between a photovoltaic panel and a power grid, so that electrical isolation is realized, and the system and personal safety are ensured.

In recent years, in order to improve the system efficiency and reduce the system cost, a power frequency transformer between a photovoltaic panel and a power grid is omitted, but the system may generate leakage current, and if the leakage current is not detected and inhibited, the system safety problem is generated.

According to the relevant provisions, the inverter should have leakage current detection means in any case when the ac circuit breaker is closed when the inverter is connected to the ac power grid. The leakage current detection means should be able to detect the total (including the dc and ac parts) real value current, the continuous residual current, and if the continuous residual current exceeds the limit, the inverter should be switched off within 0.3s and a fault signal is issued.

Leakage current detection after inversion of photovoltaic power generation, wind power generation and the like is developed from traditional coil detection to on-board circuit detection, and then is detected by the existing independent modularized leakage current sensor. At present, the leakage current sensor is mainly divided into an open loop mode and a closed loop mode, and the leakage current sensor is based on a fluxgate structure, a hall (hall) structure, an MR (magnetic resistance) structure and the like.

At present, a lead of the leakage current sensor is fixed when being manufactured and cannot be replaced at will, and when the lead is damaged or does not meet the use condition, the whole leakage current sensor needs to be replaced, so that the resource loss is caused.

SUMMERY OF THE UTILITY MODEL

Therefore, the present invention is to solve the technical problem of overcoming the defect that the wire is fixed when being manufactured and can not be replaced arbitrarily in the prior art, thereby providing an ac side leakage current sensor, including:

the induction body comprises a shell with a channel and a magnetic core arranged in the shell, and an induction coil is wound on the magnetic core;

the wire support wears to establish in the passageway and with the connection can be dismantled to the casing for fixed the wire that passes the passageway, the wire is including exposing the outer input and the output of wire support for connect on the three-phase alternating current line.

Preferably, the lead support comprises a female lead support head and a male lead support head, and the female lead support head and the male lead support head are both provided with lead accommodating cavities and are detachably connected;

the wire holds the chamber and includes that the third wire holds the chamber and is located the first wire that the third wire held the chamber both sides holds the chamber and the chamber is held to the second wire, first wire holds the chamber and the chamber is held to the second wire and is the angle bending, the wire is located the wire holds the intracavity.

Preferably, the male head of wire support is equipped with first joint position, the female head of wire support is equipped with second joint position, first joint position and second joint position wear to establish and joint in the passageway.

Preferably, the magnetic core further comprises a demagnetization circuit, wherein the demagnetization circuit is used for eliminating hysteresis generated by the magnetic core under the interference of an external magnetic field.

Preferably, the demagnetization circuit comprises a demagnetization winding wound on the magnetic core and used for generating demagnetization oscillation with gradually increasing frequency so as to eliminate hysteresis generated by the magnetic core under the interference of an external magnetic field.

Preferably, the alternating current side leakage current sensor further comprises a self-checking circuit, wherein the self-checking circuit comprises a self-checking winding, and the self-checking winding is wound on the magnetic core and used for detecting whether the alternating current side leakage current sensor has a fault or not.

Preferably, the induction main body comprises a signal processing module, the signal processing module comprises a coil interface, a filter, a zero setting circuit, a sampling resistor and an amplifying circuit, the coil interface is connected with the induction coil, and the coil interface, the filter, the zero setting circuit, the sampling resistor and the amplifying circuit are sequentially connected.

Preferably, the magnetic core is a cobalt-based magnetic core.

The utility model discloses technical scheme has following advantage:

1. the utility model provides an exchange side leakage current sensor, wire support detachably connects on the casing to the fixed wire that passes the passageway suffers to damage or unsatisfied operation requirement at the wire, can dismantle wire support from the casing, changes the wire. The alternating current side leakage current sensor does not need to replace the whole alternating current side leakage current sensor, only needs to replace a wire which is damaged or does not meet the use requirement, avoids unnecessary resource waste and increases the applicability of the alternating current side leakage current sensor.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the technical solutions in the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is an exploded view of an ac side leakage current sensor according to embodiment 1 of the present invention;

fig. 2 is a schematic structural diagram of an ac side leakage current sensor according to embodiment 1 of the present invention;

fig. 3 is a schematic structural view of a lead frame male head in the ac side leakage current sensor according to embodiment 1 of the present invention;

fig. 4 is a schematic structural diagram of a female terminal of a lead frame in an ac side leakage current sensor according to embodiment 1 of the present invention;

fig. 5 is a schematic view of a lead frame and a lead in an ac side leakage current sensor according to embodiment 1 of the present invention;

FIG. 6 is a schematic view of the lead frame of FIG. 2 with the lead frame removed;

FIG. 7 is an exploded view of FIG. 6 with the housing removed;

FIG. 8 is an exploded view of the lead, PCB and core support of FIG. 7 with the lead, PCB and core support removed;

fig. 9 is a circuit block diagram of an ac side leakage current sensor according to embodiment 1 of the present invention.

Description of reference numerals:

10. an alternating-current side leakage current sensor; 101. a lead bracket male; 1011. a first wire receiving cavity; 1012. a second wire receiving cavity; 1013. a third wire receiving cavity; 1014. a first clamping position; 102. A wire support female head; 1021. a second card is clamped; 103. a housing; 1031. a channel; 104. an upper cover of the shell; 105. a magnetic core holder; 106. a PCB board; 1061. a pin; 107. a magnetic core shell; 1071. a magnetic core accommodating cavity; 108. a magnetic core cover; 109. a magnetic core; 1091. a through hole; 110 wires; 201. a coil interface; 202. a filter; 203. a zero setting circuit; 204. sampling a resistor; 205. an amplifying circuit; 206. A self-checking circuit; 207. a power supply and a voltage regulator; 208. a reference voltage.

Detailed Description

The technical solution of the present invention will be described clearly and completely with reference to the accompanying drawings, and obviously, the described embodiments are some, but not all embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

In the description of the present invention, 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 simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. 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 invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; 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 invention can be understood in specific cases to those skilled in the art.

Furthermore, the technical features mentioned in the different embodiments of the invention described below can be combined with each other as long as they do not conflict with each other.

In the process of generating power by using clean energy such as photovoltaic power generation and wind power generation, leakage current may be generated after inversion of an inverter, and in order to detect the leakage current, an alternating current side leakage current sensor needs to be provided on the inverter. At present, the lead wires of a plurality of alternating current side leakage current sensors are fixed when leaving a factory and cannot be replaced randomly according to the use requirements, and when the lead wires are damaged or do not meet the use conditions, the whole alternating current side leakage current sensor needs to be replaced, so that the waste of resources and poor applicability are caused.

Example 1

The present embodiment provides an ac side leakage current sensor 10, the ac side leakage current sensor 10 being based on an open-loop fluxgate design that uses a closed cobalt-based magnetic core as an inductive device.

As shown in fig. 1, 2 and 6, the ac side leakage current sensor 10 includes an induction body and a wire holder, the induction body includes a housing with a passage 1031 and a magnetic core 109 disposed in the housing, an induction coil (not shown) is wound on the magnetic core 109, and the magnetic core 109 wound with the induction coil simultaneously serves as an induction part and an excitation part of the ac side leakage current sensor 10. The cross-section of the core 109 includes, but is not limited to, circular, rectangular, polygonal, etc., and the core 109 has a through hole 1091 (shown in fig. 8). In this embodiment, the cross section of the magnetic core 109 is circular.

The lead frame is inserted into the passage 1031 and detachably connected to the sensing body, and the lead frame is used for fixing the lead 110 passing through the passage 1031. The lead 110 includes input and output terminals exposed outside the lead frame for connection to electrical wires (not shown). The electric wire is a three-phase alternating current wire at the inverter side, and when the inverter generates a leakage current, the three-phase current flows through the wire 110, and the sensing body of the alternating current side leakage current sensor 10 senses the leakage current. The lead 110 is a 2-4 phase red copper current wire, and the lead support is a current wire support made by injection molding.

In the above embodiment, the wire holder is detachably attached to the housing and fixes the wires 110 passing through the passages 1031, and when the wires 110 are damaged or do not satisfy the use requirement, the wire holder can be detached from the housing and the wires 110 can be replaced. The ac side leakage current sensor 10 provided in this embodiment does not need to replace the entire ac side leakage current sensor, but only needs to replace the wire 110 that is damaged or does not meet the use requirement, thereby avoiding unnecessary resource waste and increasing the applicability of the ac side leakage current sensor 10.

As shown in fig. 3-5, the wire support comprises a male wire support head 101 and a female wire support head 102, wherein the male wire support head 101 and the female wire support head 102 both have wire receiving cavities therein, and the male wire support head 101 and the female wire support head 102 are detachably connected. The wire accommodating chamber includes a third accommodating chamber 1013 disposed in the wire holder and a first accommodating chamber 1011 and a second accommodating chamber 1012 located at both sides of the third accommodating chamber 1013, wherein the first accommodating chamber 1011 and the second accommodating chamber 1012 are bent at an angle in the wire holder. In the present embodiment, each of the first receiving chamber 1011 and the second receiving chamber 1012 includes a vertical receiving chamber parallel to the third receiving chamber 1013 and a horizontal receiving chamber extending from the vertical receiving chamber toward the third receiving chamber 1013.

In use, the lead 110 is positioned within the first receiving chamber 1011, the second receiving chamber 1012, and the third receiving chamber 1013. The three-phase current lead 110 in the third receiving chamber 1013 is fixed to the inner wall of the passage through the upper wall of the third receiving chamber, and the leads in the first receiving chamber 1011 and the second receiving chamber 1012 are fixed through the inner wall of the lateral receiving chamber.

As shown in fig. 3 and 4, the inner side of the male lead frame head 101 is provided with a first clamping position 1014, the inner side of the female lead frame head 102 is provided with a second clamping position 1021, both the first clamping position 1014 and the second clamping position 1021 are a protruding structure, and the first clamping position 1014 and the second clamping position 1021 are inserted into the passage 1031 and clamped to realize the detachable connection of the lead frame and the housing. In some embodiments, the male lead frame head 101 and the female lead frame head 102 can also be directly connected with the housing in a snap-fit, threaded, or other detachable manner.

As shown in fig. 1, 7 and 8, the induction body further includes a core protector that wraps the core 109 to prevent the core 109 from being damaged, and an induction coil (not shown) is wound on the core 109 by being wound on the core protector. In this embodiment, the magnetic core 109 is in a ring shape with a through hole 1091, the magnetic core protection device includes a magnetic core housing 107 and a magnetic core cover 108, the magnetic core housing 107 has a circular hole therein, a magnetic core accommodating cavity 1071 is further formed in the magnetic core housing 107, the magnetic core 109 is located in the magnetic core accommodating cavity 1071, and the magnetic core cover 108 is located at an opening of the magnetic core accommodating cavity 1071 to wrap the magnetic core 109. In some embodiments, the magnetic core 109 may also be rectangular, polygonal, etc. with a channel, and suitably, the magnetic core accommodating cavity 1071 in the magnetic core shell 107 is also rectangular, polygonal, etc. Since the magnetic core 109 provided in this embodiment is a closed magnetic core, it has a magnetic field resistance and a magnetic shielding device may not be provided.

As shown in fig. 1 and 7, the induction body further includes a core holder 105 having a through hole and a PCB board 106 having a through hole, the core holder 105 has an inner cavity, and a core protector wrapping a core 109 is located in the inner cavity of the core holder 105 to fix the core protector and the core 109 wrapped by the core protector. The core holder 105 and the PCB 106 may be detachably connected by means of pins, double-sided tape, or snaps. The PCB 106 is further provided with a pin 1061, and the pin 1061 is used for connecting an external device.

As shown in fig. 1 and 6, the housing includes a housing 103 and a housing upper cover 104, which are engaged with each other, and the housing 103 and the housing upper cover 104 each have a hollow cylinder therein and may be formed by injection molding, 3D printing, or other forming methods, wherein an inner diameter of one hollow cylinder is larger than an outer diameter of the other hollow cylinder, and the passage 1031 is disposed on the hollow cylinder having a smaller inner diameter. The hollow cylinders of the housing 103 and the housing upper cover 104 are fitted to each other, and a magnetic core holder 105 with a through hole, a PCB board 106 with a through hole, and a magnetic core protector wrapping a magnetic core 109 are fixed in the housing to protect the wrapped parts. The housing 103 and the housing cover 104 may also be removably connected by means of snaps, pins, threads, etc.

If the ac side leakage current sensor 10 has a fault, the ac side leakage current sensor 10 may not operate normally, and in order to find that the ac side leakage current sensor 10 has a fault in time, as shown in fig. 9, the ac side leakage current sensor 10 further includes an independent self-checking circuit 206, where the self-checking circuit 206 includes a self-checking winding wound on the magnetic core 109, and the self-checking circuit may generate a stable current flowing in the self-checking winding by using a voltage stabilizing chip and a current limiting resistor, and is used to detect whether the ac side leakage current sensor 10 operates normally under the condition that the conducting wire 110 does not operate. The high level may trigger the self-test circuit 206 to generate a current flowing in the self-test winding, so that the ac side leakage current sensor 10 can self-test without passing a current from the outside.

In some embodiments, in order to ensure that an operator can timely find a fault in the ac side leakage current sensor 10, an alarm module (not shown) may be further provided, and the alarm module may timely send an alarm prompt when the ac side leakage current sensor 10 is found to have a fault, so as to avoid an accident.

When the magnetic core 109 in the ac side leakage current sensor 10 is exposed to an external magnetic field (e.g., geomagnetism), hysteresis is generated in the magnetic core 109, and the presence of the hysteresis affects the detection of the ac side leakage current sensor 10. Therefore, the ac side leakage current sensor 10 further includes a separate degaussing circuit (not shown), which in this embodiment is a single chip plus bridge circuit and includes a degaussing winding (not shown) wound around the magnetic core 109, and when the ac side leakage current sensor 10 is switched on, the degaussing winding generates a degaussing oscillation with gradually increasing frequency, so as to eliminate the magnetic hysteresis generated by the magnetic core 109 under the external large magnetic field interference, and maintain the detection accuracy of the ac side leakage current sensor 10.

The induction main body further comprises a signal processing module, the signal processing module is integrated on the PCB 106, as shown in fig. 9, the signal processing module comprises a coil interface 201, a filter 202, a zero setting circuit 203, a sampling resistor 204 and an amplifying circuit 205, the coil interface 201 is connected with the induction coil, the coil interface 201, the filter 202, the zero setting circuit 203, the sampling resistor 204 and the amplifying circuit 205 are sequentially connected, and the signal processing module processes a signal from the induction coil and outputs the processed signal after being processed by the amplifying circuit 205. Also included is a power supply and regulator 207 and a separate reference voltage 208. the filter 202 may be an RC filter, and the signal processing module is used for magnetic modulation, filtering, and signal sampling and amplification.

In the present embodiment, the magnetic core 109 is a cobalt-based magnetic core, and the use of the cobalt-based magnetic core can increase the saturation field of the magnetic core 109, so that the ac side leakage current sensor 10 can realize a wide-range measurement. In some embodiments, magnetic core 109 may also be a permalloy magnetic core.

In the ac-side leakage current sensor 10 provided in this embodiment, the inductance of the magnetic core 109 that is easily saturated changes with the magnitude of the excitation current (the current flowing through the induction coil) due to the excitation current, and the change in inductance causes the change in magnetic flux.

When the current value in the wire 110 is zero, there is a complete symmetrical excitation voltage signal in the magnetic core 109, and the excitation current in the induction coil; when the current value in the wire 110 is not zero, the exciting current and the current in the wire 110 act on the magnetic core 109 at the same time, the saturation of the magnetic core 109 is advanced, the inductance is reduced in advance, or the current waveform is not symmetrical any more, and even harmonic current is generated. Since the degree of asymmetry of the current waveform depends on the magnitude of the current in the conductive line 110, the measurement of the current in the conductive line 110 can be accomplished by processing the waveform of the excitation current to obtain a voltage or current signal proportional to the current in the conductive line 110.

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 can be made without departing from the scope of the invention.

Claims

1. An ac side leakage current sensor, comprising:

2. The ac side leakage current sensor according to claim 1, wherein said lead frame comprises a female lead frame head and a male lead frame head, said female lead frame head and said male lead frame head each having a lead receiving cavity and being detachably connected;

3. The AC side leakage current sensor according to claim 2, wherein said male lead frame head has a first clamping position, said female lead frame head has a second clamping position, and said first and second clamping positions are inserted into said channel and clamped.

4. The ac side leakage current sensor according to claim 1, further comprising a demagnetization circuit for canceling hysteresis of said magnetic core caused by an external magnetic field.

5. The ac side leakage current sensor according to claim 4, wherein said degaussing circuit comprises a degaussing winding wound around said core for generating a degaussing oscillation with a gradually increasing frequency to eliminate hysteresis of the core under influence of an external magnetic field.

6. The ac side leakage current sensor according to claim 1, further comprising a self-test circuit including a self-test winding wound around said magnetic core for detecting whether said ac side leakage current sensor is malfunctioning.

7. The ac side leakage current sensor according to any one of claims 1-6, wherein said sensing body comprises a signal processing module, said signal processing module comprises a coil interface, a filter, a zeroing circuit, a sampling resistor and an amplifying circuit, said coil interface is connected to said sensing coil, and said coil interface, filter, zeroing circuit, sampling resistor and said amplifying circuit are connected in sequence.

8. The ac side leakage current sensor of any one of claims 1-6, wherein said magnetic core is a cobalt based magnetic core.