CN216599009U - Single-phase filter circuit and filter - Google Patents

Abstract

The utility model discloses a single-phase filter circuit and a filter, which belong to the technical field of filters, wherein the single-phase filter circuit comprises a filter unit and a switch unit, the input end of the filter unit is connected with a power grid, the output end of the filter unit is connected with a load through a driver, and the grounding end of the filter unit is grounded through the switch unit; the filtering unit is used for suppressing the noise of the driver to the power grid; the switch unit is used for controlling the connection or disconnection of the filtering unit and the ground wire when the filtering unit carries out noise suppression; the utility model provides a single-phase filter among the prior art when using, lead to the problem of earth leakage protection circuit breaker malfunction easily, when reaching the solution earth leakage protection circuit breaker malfunction trouble, guarantee the effect of the noise suppression ability of filter.

Description

Single-phase filter circuit and filter

Technical Field

The utility model relates to a wave filter technical field, in particular to single-phase filter circuit and wave filter.

Background

At present, in order to reduce the size of the filter in design, the circuit topology of several common single-phase filters selects a grounding capacitor Cy with a relatively large capacitance value. However, in practical use, when a user applies such a single-phase filter to a scene with a plurality of drives, a large leakage current may exist, and a circuit breaker with leakage protection may be installed in front of the single-phase filter for safe power utilization. However, when the leakage current in the single-phase filter exceeds half of the operating current of the earth leakage circuit breaker after the earth leakage circuit breaker is installed, the earth leakage circuit breaker may malfunction.

SUMMERY OF THE UTILITY MODEL

The utility model discloses a main aim at: the utility model provides a single-phase filter circuit and wave filter, aims at solving among the prior art single-phase wave filter when using, leads to the technical problem of earth leakage protection circuit breaker malfunction easily.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

in a first aspect, the utility model provides a single-phase filter circuit, the input and the electric wire netting of circuit are connected, and the output is connected with the load, the circuit includes:

the input end of the filtering unit is connected with the power grid, the output end of the filtering unit is connected with the load through a driver, and the grounding end of the filtering unit is grounded through the switch unit;

the filtering unit is used for suppressing the noise of the driver to the power grid;

and the switch unit is used for controlling the filtering unit to be connected or disconnected with a ground wire when the filtering unit carries out noise suppression.

Optionally, in the single-phase filter circuit, the circuit further includes a lightning protection unit, and the lightning protection unit is connected to the filter unit and the switch unit respectively;

and the lightning protection unit is used for providing lightning protection.

Optionally, in the single-phase filter circuit, the lightning protection unit includes a voltage dependent resistor VDR3, a voltage dependent resistor VDR4, and a voltage dependent resistor VDR 5;

one end of the piezoresistor VDR3 is connected with a phase line L, one end of the piezoresistor VDR4 is connected with a phase line N, the other end of the piezoresistor VDR3 and the other end of the piezoresistor VDR4 are respectively connected with one end of the piezoresistor VDR5, and the other end of the piezoresistor VDR5 is connected with the switch unit.

Optionally, in the single-phase filter circuit, the filter unit includes a capacitor Cx1, an inductor L1, a capacitor Cy1, and a capacitor Cy 2;

the capacitor Cx1 and the inductor L1 are both connected between a phase line L and a phase line N;

the capacitor Cy1 is connected between the phase line L and the switch unit;

the capacitor Cy2 is connected between the phase line N and the switching unit.

Optionally, in the single-phase filter circuit, the filter unit further includes a resistor R1;

resistor R1 is connected between phase line L and phase line N.

Optionally, in the single-phase filter circuit, the filter unit further includes a capacitor Cx2 and an inductor L2;

the capacitor Cx2 and the inductor L2 are both connected between the phase lines L and N.

Optionally, in the single-phase filter circuit, the filter unit further includes a capacitor Cy3 and a capacitor Cy 4;

the capacitor Cy3 is connected between the phase line L and the switch unit;

the capacitor Cy4 is connected between the phase line N and the switching unit.

Optionally, in the single-phase filter circuit, the filter unit further includes a capacitor Cx3 and an inductor L3;

the capacitor Cx3 and the inductor L3 are both connected between the phase lines L and N.

Optionally, in the single-phase filter circuit, the switch unit includes a ground screw K1;

one end of the grounding screw K1 is respectively connected with the lightning protection unit and the filtering unit, and the other end of the grounding screw K1 is connected with the ground wire PE.

In a second aspect, the utility model also provides a filter, the input of filter passes through earth leakage circuit breaker and is connected with the electric wire netting, and the output passes through the driver to be connected with the load, filter includes:

such as the single-phase filter circuit described above.

The utility model provides an above-mentioned one or more technical scheme can have following advantage or has realized following technological effect at least:

the utility model provides a single-phase filter circuit and wave filter, through adopting the filtering unit to restrain the noise of driver to the electric wire netting, adopt the switch unit in the filtering unit carries out the in-process of noise suppression, control filtering unit and ground wire connection or disconnection to solve the trouble of earth leakage protection circuit breaker malfunction; compare the mode that the single-phase filter of direct disconnection is connected with the driver among the prior art, the utility model discloses can not reduce the noise suppression effect of wave filter, when having reached solution earth leakage protection circuit breaker malfunction fault, guarantee the technological effect of the noise suppression ability of wave filter to, enable single-phase filter adaptation multiple different application scenes.

Drawings

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

FIG. 1 is a schematic diagram of a first prior art single-phase filter circuit;

FIG. 2 is a schematic diagram of a second prior art single-phase filter circuit;

FIG. 3 is a schematic diagram of a third prior art single-phase filter circuit;

FIG. 4 is a schematic diagram of a lightning protection circuit for a single phase driver of the prior art;

fig. 5 is a schematic diagram of the single-phase filter circuit of the present invention.

The objects, features and advantages of the present invention will be further described with reference to the accompanying drawings.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

It is to be noted that, in the present invention, the terms "comprises", "comprising" or any other variation thereof are intended to cover a non-exclusive inclusion, so that an apparatus or system including a series of elements includes not only those elements but also other elements not explicitly listed or inherent to such apparatus or system. Without further limitation, an element defined by the phrase "comprising … …" does not exclude the presence of other like elements in a device or system that comprises the element. In the present application, unless expressly stated or limited otherwise, the terms "connected" and "fixed" are to be construed broadly, and thus, for example, "connected" may be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium; either internally or in interactive relation. In the present invention, if there is a description referring to "first", "second", etc., the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying relative importance or implicit indication of the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the present invention, suffixes such as "module", "part", or "unit" used to denote elements are used only for facilitating the description of the present invention, and have no specific meaning by themselves. Thus, "module", "component" or "unit" may be used mixedly.

The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art. In addition, the technical solutions of the embodiments may be combined with each other, but it must be based on the realization of those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be considered to be absent, and is not within the protection scope of the present invention.

The driver rectifies input power frequency alternating current into direct current, and the direct current is converted into voltage with different frequencies, so that the driver can generate large electromagnetic noise, particularly, the single-phase driver gradually enters a civil environment, the electromagnetic noise is strictly limited in the civil environment, and the electromagnetic noise generated by the single-phase driver needs to be suppressed in order to meet the requirement of the civil environment on the electromagnetic noise. In a single-phase drive, except for a few types of built-in EMC (Electro Magnetic Compatibility) filters, most single-phase drives use external EMC filters, and usually filter directly from standard single-phase filters purchased by filter manufacturers.

At present, circuit topologies of several common single-phase filters are shown in fig. 1 to fig. 3, and basically, a low-pass filter is formed by adopting a passive device inductor and a capacitor, and the low-pass filter filters voltage input by a power grid and outputs the filtered voltage to loads such as a driver. In the first single-phase filter circuit in the prior art shown in fig. 1, leakage inductance of a capacitor Cx1 and a common-mode inductor L1 between a phase line L (live line) and a phase line N (neutral line) can suppress differential mode noise generated by a driver; the common mode inductance L1 and the capacitances Cy1, Cy2 can suppress the common mode noise generated by the driver. On the basis of fig. 1, in order to further improve the differential mode noise suppression capability of the single-phase filter, a second single-phase filter circuit in the prior art is obtained as shown in fig. 2, and the leakage inductance of the capacitor Cx2 and the common-mode inductor L2 between the phase lines L and N can further suppress the differential mode noise generated by the driver. On the basis of fig. 1, in order to further improve the suppression capability of the single-phase filter for differential mode noise and the suppression capability for common mode noise, a third single-phase filter circuit in the prior art is obtained as shown in fig. 3, the leakage inductance of the capacitances Cx2 and Cx3 and the common mode inductance L2 between the phase line L and the phase line N can further suppress the differential mode noise generated by the driver, and the common mode inductance L2 and the capacitances Cy3 and Cy4 can further suppress the common mode noise generated by the driver.

Analysis of the three common single-phase filter circuits shows that, during normal operation, a certain leakage current flows through the grounded capacitor Cy (Cy1, Cy2, Cy3, and Cy4), the magnitude of the leakage current is related to the capacity value of the capacitor Cy, the operating voltage and the frequency of the power supply, and when the power supply is constant, the magnitude of the leakage current is directly related to the capacity value of the capacitor Cy. Conventionally, in designing a filter, a capacitor Cy having a relatively large capacitance value is selected in order to reduce the size of the filter. However, in practice, when a user applies such a single-phase filter to a scenario of a plurality of drives, there is a large leakage current, the magnitude of which is proportional to the number of single-phase filters. For safe electricity utilization, a circuit breaker with earth leakage protection is also installed in front of the single-phase filter. However, when the leakage current in the single-phase filter exceeds half of the operating current of the earth leakage circuit breaker after the earth leakage circuit breaker is installed, the earth leakage circuit breaker may malfunction. At present, two ways are available for solving the fault, one is to replace the leakage protection circuit breaker with larger action current, but the replacement of the leakage protection circuit breaker with larger action current may cause safety risk; the other is to disconnect the single-phase filter, but this will cause the external electromagnetic noise of the driver to become significantly large, and may also affect the normal operation of the whole system.

In addition, in order to prevent surge voltage or current from damaging the driver, a lightning protection circuit is also generally separately designed at the front end of the driver for protection. As shown in fig. 4, which is a lightning protection circuit of a single-phase driver in the prior art, a Voltage Dependent Resistor VDR1(Voltage Dependent Resistor) between phase lines L and phase lines N provides inter-phase surge Voltage or current protection, and a Voltage Dependent Resistor VDR2 between phase lines N and ground lines PE provides protection against ground. Generally, the voltage dependent resistor VDR1 is selected according to 230V ac working voltage, and when a user uses a single-phase driver, he usually takes one phase from a three-phase power grid to supply power to the driver, and in an IT power grid (a kind of three-phase power grid low-voltage distribution system), when a certain phase is short-circuited, the voltage of the single-phase driver can reach 380V of the three-phase power line voltage, at this time, the voltage dependent resistor VDR1 is easy to fail, and there is a risk of fire due to failure, which results in failure to effectively protect the driver.

Therefore, in the prior art, when the single-phase filter is used, the problem that the electromagnetic noise of the driver cannot be effectively suppressed due to the fact that the filter needs to be removed after the misoperation of the earth leakage protection circuit breaker occurs easily, and the problem that the existing lightning protection circuit is prone to failure and fire risks and the like occur.

In view of the above problems in the prior art, the present invention provides a single-phase filter circuit and a filter, which includes the following embodiments:

example one

Referring to fig. 5, the present embodiment provides a single-phase filter circuit. The input end of a filter comprising the single-phase filter circuit is connected with a power grid through an earth leakage protection circuit breaker, and the output end of the filter is connected with a load through a driver.

The filter suppresses noise generated by the driver and prevents the noise from being transmitted into a power grid; in practical application, the filter receives power frequency alternating current, and outputs the alternating current to the driver after noise suppression is carried out; the driver rectifies the filtered alternating current into direct current, and the direct current is inverted to output working voltages with different frequencies to a load, so that the variable frequency control of the load is realized. The leakage protection circuit breaker provides leakage protection according to the magnitude of leakage current in the single-phase filter circuit.

As shown in the schematic circuit diagram of fig. 5, the input terminal of the single-phase filter circuit may be connected to a power grid, and the output terminal may be connected to a load, and the circuit includes:

the input end of the filtering unit is connected with the power grid, the output end of the filtering unit is connected with the load through a driver, and the grounding end of the filtering unit is grounded through the switch unit;

the filtering unit is used for suppressing the noise of the driver to the power grid;

and the switch unit is used for controlling the filtering unit to be connected or disconnected with a ground wire when the filtering unit carries out noise suppression.

In this embodiment, the input of filtering unit passes through earth leakage circuit breaker and is connected with the electric wire netting, and the output passes through single-phase driver and is connected with the load, specifically can be connected with a plurality of single-phase drivers.

Further, the filtering unit comprises a capacitor Cx1, an inductor L1, a capacitor Cy1 and a capacitor Cy 2;

the capacitor Cx1 and the inductor L1 are both connected between a phase line L and a phase line N;

the capacitor Cy1 is connected between the phase line L and the switch unit;

the capacitor Cy2 is connected between the phase line N and the switching unit.

Specifically, the inductor L1 is a common mode inductor, the capacitors Cx1, Cy1, Cy2 and the inductor L1 form low-pass filtering, the leakage inductance of the capacitor Cx1 and the inductor L1 suppresses differential mode noise of the single-phase driver, and the capacitors Cy1, Cy2 and the inductor L1 suppress common mode noise of the single-phase driver.

Furthermore, the filtering unit further comprises a resistor R1;

resistor R1 is connected between phase line L and phase line N.

Specifically, the resistor R1 is a discharge resistor, and the resistor R1 is connected in parallel with the capacitor Cx1, so that energy in the capacitor Cx1 can be discharged after the filter is powered off, and the electric shock hazard can be prevented.

Further, the filtering unit further comprises a capacitor Cx2 and an inductor L2;

the capacitor Cx2 and the inductor L2 are both connected between the phase lines L and N.

Specifically, the inductor L2 is a common-mode inductor, the capacitor Cx2 and the inductor L2 form low-pass filtering, the leakage inductance of the capacitor Cx2 and the inductor L2 can further suppress differential mode noise of the single-phase driver, and the inductor L1 and the inductor L2 can both suppress oscillation of noise in a low-frequency band in conducted transmission.

Further, the filtering unit further comprises a capacitor Cy3 and a capacitor Cy 4;

the capacitor Cy3 is connected between the phase line L and the switch unit;

the capacitor Cy4 is connected between the phase line N and the switching unit.

In particular, the capacitor Cy3, the capacitor Cy4 and the inductor L2 can further suppress the common mode noise of the single-phase driver.

Further, the filtering unit further comprises a capacitor Cx3 and an inductor L3;

the capacitor Cx3 and the inductor L3 are both connected between the phase lines L and N.

Specifically, inductance L3 is the common mode inductance, and low pass filtering is formed by capacitance Cx3 and inductance L3, compares the filter circuit of prior art, and the filter circuit of this embodiment has additionally increased one-level common mode inductance, can restrain the oscillation of noise in the high-frequency band in conducted transmission, has promoted the noise suppression effect of filter.

In this embodiment, the capacitance values of the capacitor Cx1, the capacitor Cx2, and the capacitor Cx3 are 1uF, and in order to minimize leakage current under the condition of 230VAC/50Hz, the capacitance values of the capacitor Cy1, the capacitor Cy2, the capacitor Cy3, and the capacitor Cy4 are 10nF, the inductance L1 and the inductance L2 both use a manganese core common mode inductance, the inductance is 1.2mH @100kHz, the inductance L3 uses a nickel core common mode inductance, and the inductance is 0.65uH @100 kHz.

Further, the switch unit includes a ground screw K1;

one end of the grounding screw K1 is connected with the filtering unit, and the other end is connected with the ground wire PE.

In this embodiment, the capacitance Cy of the phase line to the ground (the capacitance Cy1, the capacitance Cy2, the capacitance Cy3, and the capacitance Cy4) is designed to be selectively grounded through the grounding screw K1, when the screw is screwed on, the capacitance Cy to the ground is grounded, and when the screw is screwed off, the capacitance Cy to the ground is disconnected from the ground.

In the specific circuit topology of the embodiment, a capacitor Cx1, a resistor R1, an inductor L1, a capacitor Cx2, an inductor L2, a capacitor Cx3 and an inductor L3 are sequentially arranged between a phase line L and a phase line N, the capacitor Cx1 is connected with a power grid, and the inductor L3 is connected with a load; the capacitors Cy1 and Cy2 are laid out before the inductance L2, the capacitors Cy3 and Cy4 are laid out before the inductance L3, and the capacitors Cy1 and Cy2, and the capacitors Cy3 and Cy4 are all connected to the ground line PE by means of a ground screw K1.

In the working process, a certain leakage current is generated in the capacitor Cy to the ground, the magnitude of the leakage current is in direct proportion to the number of the filters, when the magnitude of the leakage current exceeds half of the action current in the leakage protection circuit breaker, the leakage protection circuit breaker can trip out due to leakage protection, if the filter is possibly required to be removed according to the existing method, the system breaks down due to the increase of electromagnetic noise, and the production is easily influenced; the filter circuit of this embodiment, through setting up the switch unit, come the selectivity ground connection of electric capacity Cy in the control filter unit according to user's demand, effectively solve the problem of earth leakage protection circuit breaker malfunction to, provide the suppression ability to single-phase driver electromagnetic noise.

The single-phase filter circuit of the embodiment provides a new filter topology, solves the problem of misoperation of the leakage protection circuit breaker, and solves the fault of the misoperation of the leakage protection circuit breaker by adopting the filter unit to suppress noise of a driver to a power grid and adopting the switch unit to control the connection or disconnection of the filter unit and a ground wire in the process of noise suppression of the filter unit; compare the mode that the single-phase filter of direct disconnection is connected with the driver among the prior art, the utility model discloses when having reached the solution earth leakage protection circuit breaker malfunction trouble, guarantee the technological effect of the certain noise suppression ability of wave filter to, enable single-phase filter adaptation multiple different application scenes. The single-phase filter circuit of the embodiment also improves the noise suppression effect of the filter.

The single-phase filter circuit of this embodiment, realize the selective ground connection to ground capacitance Cy (electric capacity Cy1, electric capacity Cy2, electric capacity Cy3 and electric capacity Cy4) with ground screw K1, can make this single-phase filter be applied to more complicated scenes, when single-phase driver gets electricity from the three-phase electric network, the interphase voltage-sensitive of external lightning protection circuit is failed easily and is fired on fire, under the IT electric network, can prevent interphase voltage-sensitive failure and fire and the failure problem to ground capacitance Cy through disconnection ground screw K1, when the earth leakage protection circuit breaker is equipped with to the front stage, the problem of earth leakage protection circuit breaker malfunction is solved to accessible disconnection ground screw K1, and the production efficiency is improved.

Example two

With reference to fig. 5, on the basis of the first embodiment, the present embodiment provides a single-phase filter circuit. The circuit further comprises:

the lightning protection unit is respectively connected with the filtering unit and the switch unit;

and the lightning protection unit is used for providing lightning protection.

Utilize external filter space, integrated the lightning protection unit that can avoid alternate piezo-resistor to catch fire, can show the lightning protection effect who promotes single-phase driver, except can providing basic EMC filtering for single-phase driver, can also effectively protect the driver trouble because of surge voltage or electric current arouse.

Further, the lightning protection unit comprises a voltage dependent resistor VDR3, a voltage dependent resistor VDR4 and a voltage dependent resistor VDR 5;

one end of the piezoresistor VDR3 is connected with a phase line L, one end of the piezoresistor VDR4 is connected with a phase line N, the other end of the piezoresistor VDR3 and the other end of the piezoresistor VDR4 are respectively connected with one end of the piezoresistor VDR5, and the other end of the piezoresistor VDR5 is connected with the switch unit.

In this embodiment, the piezoresistors VDR3 and VDR4 adopt two piezoresistors with the same specification, and the grounded piezoresistor VDR5 is led out from the connection point of the two piezoresistors. In order to make the single-phase driver meet the surge test requirements in the IEC 61800-3 standard, and simultaneously take the risk that the phase-to-phase voltage of the single-phase driver may rise to 380V, the voltage-dependent voltages of the piezoresistor VDR3 and the piezoresistor VDR4 are 470V and the voltage-dependent voltage of the piezoresistor VDR5 is 910V.

The lightning protection unit of the embodiment can effectively prevent the interphase voltage dependent resistor VDR3 from being ignited when the voltage between the phase line L and the phase line N reaches the line voltage.

Further, the switch unit includes a ground screw K1;

one end of the grounding screw K1 is respectively connected with the lightning protection unit and the filtering unit, and the other end of the grounding screw K1 is connected with the ground wire PE.

In this embodiment, the capacitor Cy and the varistor VDR5 of the phase line to the ground are designed to be selectively grounded through the grounding screw K1, when the screw is screwed on, the capacitor Cy and the varistor VDR5 to the ground are grounded, and when the screw is screwed off, the capacitor Cy and the varistor VDR5 to the ground are disconnected from the ground.

In the working process, when the single-phase driver is used under an IT power grid, if one of the phase-to-ground drivers is short-circuited, pulse voltage is superposed on a capacitor CY and a piezoresistor VDR5 to the ground, within a relatively short time, a VDR5 may have a failure and fire risk, and the capacitor Cy may also generate heat and fail due to continuous large current flowing, but due to the fact that the switch unit is arranged in the embodiment, after the single-phase driver is selectively grounded, a grounding screw K1 can be screwed under a TN/TT power grid (the other two types of low-voltage power distribution systems of the three-phase power grid), and normal application is guaranteed; in an IT power grid, the grounding screw K1 is disconnected, so that the capacitor Cy and the piezoresistor VDR5 can be disconnected with the ground, and damage is prevented.

The single-phase filter circuit of this embodiment through with the integrated single-phase filter of lightning protection circuit, has reduced the rack usage space, indirectly saves the cost, can effectively protect the single-phase driver of back level because of the damage that surge voltage or electric current appear, behind the single-phase filter of installation this embodiment, originally external lightning protection circuit on single-phase driver can directly save, and then has reduced the volume of single-phase driver.

EXAMPLE III

This embodiment provides a filter, the input of filter passes through earth leakage protection circuit breaker and is connected with the electric wire netting, and the output passes through the driver and is connected with the load, the filter includes:

a single-phase filter circuit.

The specific structure of the single-phase filter circuit refers to the above embodiments, and since this embodiment employs all technical solutions of all the above embodiments, all beneficial effects brought by the technical solutions of the above embodiments are at least achieved, and are not described in detail herein.

The filter can be suitable for various application scenes, and particularly can be suitable for the scene of simultaneously connecting a plurality of single-phase drivers. The single-phase driver using the filter can utilize the space of an external filter, integrates the lightning protection unit, improves the lightning protection effect of the single-phase driver, and effectively protects the driver faults caused by surge voltage or current.

It should be noted that the numbers of the embodiments of the present invention are only for description, and do not represent the advantages and disadvantages of the embodiments. The above is only the optional embodiment of the present invention, and not therefore the limit of the patent scope of the present invention, all the concepts of the present invention utilize the equivalent structure transformation of the content of the specification and the attached drawings, or directly or indirectly applied to other related technical fields, all included in the patent protection scope of the present invention.

Claims (10)

1. A single-phase filter circuit having an input connected to a power grid and an output connected to a load, the circuit comprising:

the input end of the filtering unit is connected with the power grid, the output end of the filtering unit is connected with the load through a driver, and the grounding end of the filtering unit is grounded through the switch unit;

the filtering unit is used for suppressing the noise of the driver to the power grid;

and the switch unit is used for controlling the filtering unit to be connected or disconnected with a ground wire when the filtering unit carries out noise suppression.

2. The single-phase filter circuit of claim 1, further comprising a lightning protection unit connected to the filter unit and the switch unit, respectively;

and the lightning protection unit is used for providing lightning protection.

3. The single-phase filter circuit as recited in claim 2, wherein the lightning protection unit comprises a voltage dependent resistor VDR3, a voltage dependent resistor VDR4, and a voltage dependent resistor VDR 5;

one end of the piezoresistor VDR3 is connected with a phase line L, one end of the piezoresistor VDR4 is connected with a phase line N, the other end of the piezoresistor VDR3 and the other end of the piezoresistor VDR4 are respectively connected with one end of the piezoresistor VDR5, and the other end of the piezoresistor VDR5 is connected with the switch unit.

4. The single-phase filter circuit of claim 1, wherein the filter unit comprises a capacitance Cx1, an inductance L1, a capacitance Cy1, and a capacitance Cy 2;

the capacitor Cx1 and the inductor L1 are both connected between a phase line L and a phase line N;

the capacitor Cy1 is connected between the phase line L and the switch unit;

the capacitor Cy2 is connected between the phase line N and the switching unit.

5. The single-phase filter circuit of claim 4, wherein the filter unit further comprises a resistor R1;

resistor R1 is connected between phase line L and phase line N.

6. The single-phase filter circuit of claim 4, wherein the filter cell further comprises a capacitance Cx2 and an inductance L2;

the capacitor Cx2 and the inductor L2 are both connected between the phase lines L and N.

7. The single-phase filter circuit of claim 6, wherein the filter unit further comprises a capacitor Cy3 and a capacitor Cy 4;

the capacitor Cy3 is connected between the phase line L and the switch unit;

the capacitor Cy4 is connected between the phase line N and the switching unit.

8. The single-phase filter circuit of claim 7, wherein the filter cell further comprises a capacitance Cx3 and an inductance L3;

the capacitor Cx3 and the inductor L3 are both connected between the phase lines L and N.

9. The single-phase filter circuit of claim 2, wherein the switching unit includes a ground screw K1;

one end of the grounding screw K1 is respectively connected with the lightning protection unit and the filtering unit, and the other end of the grounding screw K1 is connected with the ground wire PE.

10. A filter, wherein an input of the filter is connected to a power grid through a leakage circuit breaker, and an output of the filter is connected to a load through a driver, the filter comprising:

the single-phase filter circuit of any one of claims 1 to 9.

Images