CN210867491U - Filter circuit, switching power supply and air conditioner - Google Patents
Filter circuit, switching power supply and air conditioner Download PDFInfo
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- CN210867491U CN210867491U CN201921595326.8U CN201921595326U CN210867491U CN 210867491 U CN210867491 U CN 210867491U CN 201921595326 U CN201921595326 U CN 201921595326U CN 210867491 U CN210867491 U CN 210867491U
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- switching power
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Abstract
The utility model discloses a filter circuit, switching power supply and air conditioner, filter circuit includes at least a set of wave filter, ground capacitance, input terminal and output terminal, the wave filter includes magnetic ring and low pass filter, the input of magnetic ring is connected the input terminal, the output of magnetic ring is connected low pass filter's input, low pass filter's output is connected output terminal is connected to ground capacitance's one end and common port, ground capacitance's other end ground connection. The utility model discloses a magnetic ring decay common mode noise through low pass filter suppression differential mode noise, can also restrain the conducted interference that switching power supply produced and scurry into the load, also can restrain the noise interference switching power supply that the load produced to effectual reduction switching power supply's EMI has promoted the quality of air conditioner.
Description
Technical Field
The utility model belongs to the technical field of switching power supply technique and specifically relates to a filter circuit, switching power supply and air conditioner are related to.
Background
The switching power supply is widely applied to the variable frequency air conditioner due to the advantages of small volume, high power density and the like, but the switching power supply has poor Electromagnetic Interference (EMI) resistance, so that the EMI test of the whole machine cannot pass.
Chinese invention patent CN104104216A discloses a switching power supply filter circuit, which focuses on filtering out harmonic waves and suppressing surge current impact; chinese utility model patent CN204559381U discloses filter circuit, switching power supply and domestic appliance with electromagnetic interference suppression function, with filter circuit design integration in switching power supply, but the commonality of the filter circuit of above two kinds is not high and the filtering effect is limited.
SUMMERY OF THE UTILITY MODEL
The utility model aims to overcome the weak point among the prior art and provide filter circuit, switching power supply and air conditioner, very big increase the filtering effect, the effectual EMI that reduces the switch power supply terminal.
The purpose of the utility model is realized through the following technical scheme of three aspect:
in a first aspect, the utility model provides a switching power supply's filter circuit, filter circuit includes at least a set of wave filter, ground capacitance, input terminal and output terminal, the wave filter includes magnetic ring and low pass filter, the input of magnetic ring is connected input terminal, the output of magnetic ring is connected low pass filter's input, low pass filter's output is connected output terminal is connected to ground capacitance's one end and common port, ground capacitance's other end ground connection.
Preferably, the filter circuit includes a first filter and a second filter, the first filter and the second filter are symmetrical, and a capacitor is connected between the first filter and the second filter.
Preferably, each group of low-pass filters includes a capacitor and a choke coil, one end of the capacitor is connected to the input end of the choke coil, the common end of the capacitor is connected to the input terminal, the output terminal of the choke coil is connected to the output terminal, and the other end of the capacitor is grounded.
Preferably, each set of filter blocks comprises a first magnetic ring and a second magnetic ring.
Preferably, the first magnetic ring is a first nanocrystalline magnetic ring, the second magnetic ring is a second nanocrystalline magnetic ring, the first nanocrystalline magnetic ring is wound to form a first common mode choke coil, and the second nanocrystalline magnetic ring is wound to form a second common mode choke coil.
Preferably, the first common mode choke coil and the second common mode choke coil have the same magnetic flux direction.
In a second aspect, the present invention provides a switching power supply, which includes the filter circuit of the first aspect.
In a third aspect, the present invention provides an air conditioner comprising the switching power supply of the second aspect.
Preferably, the air conditioner further comprises an artificial power supply network (LISN) and an electric load, wherein the input end of the artificial power supply network (LISN) is connected with an external power supply, the output end of the artificial power supply network (LISN) is connected with the input end of a switching power supply, the output end of the switching power supply is connected with the input end of the filter circuit, and the output end of the filter circuit is connected with the electric load.
Preferably, the electric load is one or more of an air conditioner control panel, a motor driver and an air conditioner display panel.
The utility model has the advantages that: the utility model provides a filter circuit, switching power supply and air conditioner through magnetic ring attenuation common mode noise, through low pass filter suppression differential mode noise, can also restrain the conducted interference that switching power supply produced and scurry into the load, also can restrain the noise interference switching power supply that the load produced to effectual reduction switching power supply's EMI.
Drawings
The invention is further described with the aid of the accompanying drawings, in which, however, the embodiments do not constitute any limitation to the invention, and for a person skilled in the art, other drawings can be derived from the following drawings without inventive effort.
Fig. 1 is a schematic circuit diagram of a filter circuit according to an embodiment of the present invention.
Fig. 2 is a schematic diagram of a filtering of a switching power supply of an air conditioner according to an embodiment of the present invention.
Fig. 3 is a disturbance voltage test chart measured in the case where the switching power supply according to an embodiment of the present invention does not use a filter circuit.
Fig. 4 is a disturbance voltage test chart measured in the case where the switching power supply according to an embodiment of the present invention uses a filter circuit.
Detailed Description
In order to make the technical solution of the present invention better understood, the technical solution of 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 shall belong to the protection scope of the present invention.
As shown in fig. 1, the filter circuit of the switching power supply of this embodiment includes two sets of filters, a ground capacitor, an Input terminal Input and an Output terminal Output, each set of filter includes a magnetic ring and a low-pass filter, an Input end of the magnetic ring is connected to the Input terminal Input, an Output end of the magnetic ring is connected to an Input end of the low-pass filter, an Output end of the low-pass filter is connected to one end of the ground capacitor, a common end of the low-pass filter is connected to the Output terminal Output, and the other end of the ground capacitor is grounded.
According to the principle of the LC filter, as the number n of stages increases, the performance of the filter will improve rapidly, but the cost also increases, and the cost of the 2-stage LC filter and the filtering performance are the optimal combination, so that two sets of filters are adopted in this embodiment.
The two groups of filters are respectively a first filter and a second filter which are symmetrical structures, and a capacitor C2 is connected between the first filter and the second filter.
As shown in fig. 2, the filter circuit of this embodiment is used in a switching power supply for reducing EMI at an output terminal of the switching power supply, and the switching power supply is used in an air conditioner, the air conditioner includes an artificial power supply network (LISN) and an electrical load, an input terminal of the LISN is connected to an external power supply, an output terminal of the LISN is connected to an input terminal of the switching power supply, an output terminal of the switching power supply is connected to an input terminal of the filter circuit, and an output terminal of the filter circuit is connected to the electrical load.
The electric load may be any device that uses a switching power supply to supply power to the inside of the air conditioner, such as an air conditioner control board, a motor driver, an air conditioner display board, and the like.
The power grid voltage is filtered by the LISN and then supplies power to the switching power supply, the switching power supply rectifies alternating-current voltage AC (200V-240V/50 Hz) into direct-current voltage required by the air conditioner control panel and outputs the direct-current voltage to the filter circuit, and the direct-current voltage is output to a subsequent load circuit after passing through the filter circuit.
The first filter comprises a capacitor C1, a choke coil L3, a nanocrystalline magnetic ring L1 and a nanocrystalline magnetic ring L2, the second filter comprises a nanocrystalline magnetic ring L4, a nanocrystalline magnetic ring L5, a choke coil L6 and a capacitor C3, the ground capacitor comprises a first ground capacitor C4 and a second ground capacitor C5, one end of a capacitor C1 is connected with a first Input terminal Input1 and the common end is connected with the Input end of the nanocrystalline magnetic ring L1, the other end of a capacitor C1 is connected with a second Input terminal Input2 and the common end is connected with the Input end of the nanocrystalline magnetic ring L2, the output end of the nanocrystalline magnetic ring L2 is connected with the Input end of the choke coil L2, the output end of the choke coil L2 is connected with one end of the capacitor C2 and the common end is connected with one end of the capacitor C2 and the Input end of the nanocrystalline magnetic ring L2, the output end of the nanocrystalline magnetic ring L2 is connected with the other end of the capacitor C2 and the common end of the capacitor C2 is connected with the ground, and the Input end of the capacitor C2, an Output end of the nanocrystalline magnetic ring L4 is connected with an input end of a choke coil L6, an Output end of a choke coil L6 is connected with one end of a capacitor C3, a common end of the choke coil is connected with a first Output terminal Output1, an Output end of the nanocrystalline magnetic ring L5 is connected with the other end of a capacitor C3, and a common end of the nanocrystalline magnetic ring L5 is connected with a second Output terminal Output 2.
In the first filter, the high-frequency bypass capacitor C1 and the choke coil L3 form a low-pass filter of the input port, so that differential mode noise on direct current incoming lines can be suppressed, and the air-conditioning control panel is prevented from being interfered by the low-pass filter. Common mode chokes L1 and L2 wound by nanocrystalline magnetic rings L1 and L2 effectively attenuate common mode noise. When a common mode current passes through the common mode choke coil L1 and the common mode choke coil L2, the magnetic flux directions of the common mode choke coil L1 and the common mode choke coil L2 are the same, so that the magnetic fields generated by the two common mode choke coils are mutually strengthened, the total inductance is rapidly increased after coupling, a large inductive reactance is presented, a common mode signal is not easy to pass, and the attenuation of common mode noise is realized.
In the second filter, the high-frequency bypass capacitor C3 and the choke coil L6 form a low-pass filter of an output port, and differential mode noise generated by the air-conditioning control panel is suppressed. Common mode chokes L4 and L5 wound by the nanocrystalline magnetic rings L4 and L5 effectively attenuate common mode noise. The two groups of filters are of symmetrical structures and form a bidirectional filter, so that not only can conduction interference generated by the switch power supply be inhibited from entering the air-conditioning control panel, but also noise generated by the air-conditioning control panel can be inhibited from interfering the switch power supply.
The grounding capacitors C4 and C5 can suppress high-frequency common-mode noise and introduce the high-frequency common-mode noise into a common ground network.
As shown in fig. 3, when the filter circuit of this embodiment is connected to the switching power supply output terminal of the air conditioner, the terminal disturbance voltage of the switching power supply drops by about 20 dB.
The utility model discloses a filter circuit, switching power supply and air conditioner through magnetic ring attenuation common mode noise, through low pass filter suppression differential mode noise, can also restrain the conducted interference that switching power supply produced and scurry into the load, also can restrain the noise interference switching power supply that the load produced to effectual reduction switching power supply's EMI has promoted the quality of air conditioner.
It should be finally noted that the above embodiments are only intended to illustrate the technical solutions of the present invention, and not to limit the scope of the present invention, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present invention can be modified or replaced with equivalents without departing from the spirit and scope of the technical solutions of the present invention.
Claims (10)
1. The filter circuit is characterized by comprising at least one group of filters, a grounded capacitor, an input terminal and an output terminal, wherein each filter comprises a magnetic ring and a low-pass filter, the input end of the magnetic ring is connected with the input terminal, the output end of the magnetic ring is connected with the input end of the low-pass filter, the output end of the low-pass filter is connected with one end of the grounded capacitor, the common end of the low-pass filter is connected with the output terminal, and the other end of the grounded capacitor is grounded.
2. A filter circuit as claimed in claim 1, wherein said filter circuit comprises a first filter and a second filter, said first filter and said second filter having a symmetrical configuration, and a capacitor connected between said first filter and said second filter.
3. A filter circuit as claimed in claim 1, wherein each of said groups of low-pass filters includes a capacitor and a choke, one end of said capacitor being connected to an input terminal of said choke and a common terminal being connected to said input terminal, an output terminal of said choke being connected to said output terminal, and the other end of said capacitor being grounded.
4. A filter circuit as recited in claim 1, wherein each of said sets of filter bricks comprises a first magnetic loop and a second magnetic loop.
5. The filter circuit according to claim 4, wherein the first magnetic ring is a first nanocrystalline magnetic ring, the second magnetic ring is a second nanocrystalline magnetic ring, the first nanocrystalline magnetic ring is wound to form a first common mode choke coil, and the second nanocrystalline magnetic ring is wound to form a second common mode choke coil.
6. A filter circuit as claimed in claim 5, wherein the first common mode choke and the second common mode choke have the same magnetic flux direction.
7. A switching power supply, characterized in that it comprises a filter circuit according to any one of claims 1-6.
8. An air conditioner characterized in that it comprises the switching power supply of claim 7.
9. An air conditioner according to claim 8, further comprising an artificial power supply network (LISN) having an input connected to an external power source, an output connected to an input of a switching power supply, an output connected to an input of said filter circuit, and an electrical load.
10. An air conditioner according to claim 9, wherein the electric loads are one or more of an air conditioner control board, a motor driver, and an air conditioner display board.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921595326.8U CN210867491U (en) | 2019-09-24 | 2019-09-24 | Filter circuit, switching power supply and air conditioner |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921595326.8U CN210867491U (en) | 2019-09-24 | 2019-09-24 | Filter circuit, switching power supply and air conditioner |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN210867491U true CN210867491U (en) | 2020-06-26 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201921595326.8U Active CN210867491U (en) | 2019-09-24 | 2019-09-24 | Filter circuit, switching power supply and air conditioner |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN210867491U (en) |
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2019
- 2019-09-24 CN CN201921595326.8U patent/CN210867491U/en active Active
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