CN210985938U - High-frequency EMC filter circuit and household appliance - Google Patents
High-frequency EMC filter circuit and household appliance Download PDFInfo
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- CN210985938U CN210985938U CN201921843189.5U CN201921843189U CN210985938U CN 210985938 U CN210985938 U CN 210985938U CN 201921843189 U CN201921843189 U CN 201921843189U CN 210985938 U CN210985938 U CN 210985938U
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Abstract
The utility model provides a high frequency EMC filter circuit and domestic appliance, high frequency EMC filter circuit includes magnetic ring, common mode choke coil, first filter capacitor group, second filter capacitor group and filter module, the input of first filter capacitor group is connected the commercial power is connected to common mode choke coil's input and public end, cup joint on the wire of first filter capacitor group connection commercial power the magnetic ring, common mode choke coil's output is connected the input of second filter capacitor group, first filter capacitor group or the output of second filter capacitor group is connected filter module's input, filter module's output is connected first filter capacitor or the output and the public end ground connection of second filter capacitor group. By adding the filter module between the first filter capacitor bank or the second filter capacitor bank and the ground, the filter level number of the high-frequency EMC filter circuit is reduced, and therefore the high-frequency band (10M-300M) common-mode electromagnetic interference is filtered at low cost.
Description
Technical Field
The utility model relates to an electronic circuit technical field, concretely relates to high frequency EMC filter circuit and domestic appliance.
Background
The common mode filter is used for filtering common mode interference generated by electrical equipment so as to meet the requirements of electromagnetic compatibility standards. A common structure of the common-mode filter includes a common-mode capacitor (also referred to as Y capacitor) and a common-mode inductor, and common-mode interference is reduced by a common-mode impedance of the common-mode inductor and a bypass effect of the common-mode capacitor. The common mode filter is generally used for conducting electromagnetic interference, and the action frequency band is 150 kHz-30 MHz.
The standard exceeding of electromagnetic interference of a high frequency band (10 MHz-300 MHz) is a common problem encountered by electromagnetic compatibility test. For high-frequency common-mode interference, a high-frequency EMC filter circuit commonly used in household appliances (such as an air conditioner outdoor unit) is shown in fig. 1, and a two-stage topology filter circuit is generally adopted, and is composed of two groups of common-mode chokes and a Y capacitor, and is wound into a magnetic ring at a power supply inlet. The filtering design structure has the filtering effect as shown in fig. 4, interference peaks occur near the high frequency 32M, and the implementation space needs to be increased.
Patent CN103477544B proposes an active common mode filter circuit, but the circuit needs to use high voltage transistors and auxiliary power supply, and has poor reliability and high circuit cost. Patent CN104518721B discloses a compressor control system of inverter air conditioner and a noise suppression method thereof, which are used for filtering current feedback signals of the compressor of the inverter air conditioner through a dual T network wave trap, but are not suitable for filtering high voltage and high current strong power EMI.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to avoid the weak point among the prior art and provide a high frequency EMC filter circuit and domestic appliance, be domestic appliance noise elimination interference signal through low-cost high frequency EMC filter circuit.
The purpose of the utility model is realized through the following technical scheme:
in a first aspect, the utility model provides a high frequency EMC filter circuit, including magnetic ring, common mode choke, first filter capacitor group, second filter capacitor group and filter module, the input of first filter capacitor group is connected the commercial power is connected to common mode choke's input and common port, cup joint on the wire of first filter capacitor group connection commercial power the magnetic ring, common mode choke's output is connected the input of second filter capacitor group, first filter capacitor group or the output of second filter capacitor group is connected filter module's input, filter module's output is connected first filter capacitor or the output and the common port ground connection of second filter capacitor group.
Preferably, the filtering module is a grounded magnetic ring or a grounded resistor.
Preferably, the material of the grounding magnetic ring is one or more of a ferrite material, an iron powder core material and a magnetic powder core material.
Preferably, the inner diameter of the grounding magnetic ring is 3-5 mm.
Preferably, the impedance of a single loop of the magnetic ring is more than 30 omega within the frequency of 10MHz-300 MHz.
Preferably, the ground resistance is an oxide film resistance or a metal film resistance.
Preferably, the resistance value of the grounding resistor is 30-100 omega, and the rated power of the grounding resistor is more than 2W.
Preferably, the first filter capacitor bank comprises two Y capacitors, one ends of the two Y capacitors are respectively connected with the mains supply zero line and the mains supply live line, and the other ends of the two Y capacitors are connected together and connected with the input end of the grounding module or the ground; the second filter capacitor group also comprises two Y capacitors, one ends of the two Y capacitors are respectively connected with the commercial power zero line and the commercial power live line, and the other ends of the two Y capacitors are connected together and connected with the input end or the ground of the filter module.
Preferably, the common mode choke coil comprises a magnetic core and a coil, the magnetic core is made of ferrite materials or amorphous materials, the coil is formed by sequential winding or butterfly winding when being a single-layer coil, the coil is formed by winding a plurality of coil sections in a segmented mode when being a multi-layer coil, and the coil sections are insulated from the coil sections by resin plates.
In a second aspect, the present invention further provides a household electrical appliance, which includes the first aspect of the high frequency common mode rejection circuit.
According to the above technical scheme, the utility model discloses following beneficial effect has: the utility model provides a high frequency EMC filter circuit and domestic appliance through increase filter module between first filter capacitor group or second filter capacitor group and ground, has reduced high frequency EMC filter circuit's wave filter progression to low-cost realization high frequency channel (10M-300M) common mode electromagnetic interference's filtering.
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 circuit structure diagram of a conventional two-stage EMC filter circuit.
Fig. 2 is a circuit configuration diagram of the high-frequency EMC filter circuit of embodiment 1 of the present invention.
Fig. 3 is a schematic circuit configuration diagram of a high-frequency EMC filter circuit according to embodiment 2 of the present invention.
Fig. 4 is a graph of conducted EMI test results obtained based on the two-stage EMC filter circuit described in fig. 1.
Fig. 5 is a graph of conducted EMI test results obtained based on the high frequency EMC filter circuit described in fig. 2.
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.
As shown in fig. 2, the high-frequency EMC filter circuit of this embodiment is characterized by including a magnetic loop a, a common mode choke, a first filter capacitor bank, a second filter capacitor bank, and a filter module, wherein an input end of the first filter capacitor bank is connected to an input end of the common mode choke and a common end of the first filter capacitor bank is connected to a mains supply, the first filter capacitor bank is connected to a wire of the mains supply and sleeved with the magnetic loop, an output end of the common mode choke is connected to an input end of the second filter capacitor bank, an output end of the second filter capacitor bank is connected to an input end of the filter module, and an output end of the filter module is connected to an output end of the first filter.
The filtering module in this embodiment is a grounded magnetic ring B, which has a very low inductive impedance value at a low frequency band, and does not affect transmission of a useful signal on a data line or a signal line. Starting at about 10MHz in the high frequency band, the impedance increases, the inductive reactance component remains small, and the resistive component increases rapidly, absorbing and dissipating the EMI interference energy in the high frequency band in the form of heat.
The grounding magnetic ring B is made of one or a combination of a plurality of ferrite materials, iron powder core materials and magnetic powder cores, wherein the ferrite magnetic ring B mainly comprises a nickel-zinc ferrite magnetic ring and a manganese-zinc ferrite magnetic ring, the nickel-zinc ferrite magnetic ring B is suitable for inhibiting the electromagnetic interference of a high frequency band, and the manganese-zinc ferrite magnetic ring is suitable for inhibiting the electromagnetic interference of a low frequency band. Therefore, the nickel-zinc ferrite magnetic ring B is selected in this embodiment, and the grounding magnetic ring B is sleeved on the wire between the second filter capacitor bank and the ground, so as to suppress the electromagnetic interference in the high frequency band.
The inner diameter of the nickel-zinc ferrite magnetic ring B can be any value of 3mm-5mm, the inner diameter of the magnetic ring B is selected according to the length of the outer diameter of the cable, the larger the difference value between the inner diameter and the outer diameter of the magnetic ring B is, the larger the longitudinal height is, the larger the impedance of the ferrite material is, the better the filtering effect of the magnetic ring B is, but the inner diameter of the magnetic ring B must be tightly wrapped by the cable to avoid magnetic leakage, so the nickel-zinc ferrite magnetic ring B with the inner diameter of 3mm is selected in the embodiment.
Since the larger the impedance of the magnetic ring B made of ferrite material is, the better the filtering effect of the magnetic ring B is, in this embodiment, the impedance of a single loop of the magnetic ring B needs to be greater than 30 Ω within the frequency range of 10MHz-300MHz, and since the impedance of the magnetic ring B increases with the increase of the frequency, in this embodiment, the impedance at 30MHz is not lower than 30 Ω.
In this embodiment, the common mode choke coil includes a core and a coil, the core is made of ferrite material, and the coil is formed by sequential winding when the coil is a single-layer coil.
The first filter capacitor group comprises two Y capacitors, one ends of the two Y capacitors are respectively connected with a mains supply zero line and a mains supply live wire, and the other ends of the two Y capacitors are connected together and grounded; the second filter capacitor group also comprises two Y capacitors, one ends of the two Y capacitors are respectively connected with the commercial power zero line and the commercial power live wire, and the other ends of the two Y capacitors are connected together and connected with the input end of the filter module.
The Y capacitor in this embodiment is a ceramic capacitor, and the size of the capacitor is usually 10nF, which is much larger than the parasitic capacitance of the common mode choke. The impedance of the first filter capacitor combination and the impedance of the second filter capacitor combination are smaller than 10 omega in the frequency range of 10MHz-30 MHz, and the high-frequency band resonant current is directly conducted by combining the two Y capacitors with the first filter capacitor combination and the two Y capacitors with the second filter capacitor combination.
As shown in fig. 5, compared with the interference peak occurring near the high frequency 32M in fig. 1, the EMI testing effect performed by using the high frequency EMC filter circuit of this embodiment is that the interference peak of the 32M is effectively suppressed by the suppression effect of the grounding magnetic ring B on the electromagnetic interference.
As shown in fig. 3, the difference between this embodiment and embodiment 1 is that the filtering module in this embodiment uses a ground resistor, the first filtering capacitor bank or the second filtering capacitor bank transmits the electromagnetic interference in the high frequency band to the ground resistor, and the electromagnetic interference is consumed by heat generation, so as to suppress the electromagnetic interference signal in the high frequency band.
The grounding resistor can be an oxide film resistor or a metal film resistor, and the metal film resistor has a small volume, low noise, high precision, stable performance, and a simple and light structure, so the metal film resistor is selected in the embodiment.
The resistance value of the grounding resistor is any value between 30 and 100 omega, and the resistor of 33 omega is selected in the embodiment. The rated power of the ground resistor is greater than 2W, the electromagnetic interference signal is consumed in a heating mode through the ground resistor, therefore, the voltage of the electromagnetic interference signal can be completely connected to the two ends of the ground resistor, the two ends of the ground resistor have larger voltage when the larger electromagnetic interference signal appears, and the power P = U of the ground resistor2The resistance of the ground resistor is constant, and the voltage U across the ground resistor is determined by the magnitude of the electromagnetic interference signal, so a larger-power resistor is required, and therefore the ground resistor in the embodiment needs to be larger than 2W.
Compared with embodiment 1, the embodiment is more convenient to implement and has lower cost.
Embodiment 3, a household appliance.
A household appliance comprises the high-frequency EMC filter circuit of embodiment 1 or embodiment 2, and the household appliance has better EMC performance, lower manufacturing cost and more reliability in use through the high-frequency EMC filter circuit.
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 utility model provides a high frequency EMC filter circuit, its characterized in that, includes magnetic ring, common mode choke, first filter capacitor group, second filter capacitor group and filter module, the input of first filter capacitor group is connected the commercial power is connected to the input of common mode choke and common port, cup joint on the wire of commercial power is connected to first filter capacitor group the magnetic ring, the output of common mode choke is connected the input of second filter capacitor group, first filter capacitor group or the output of second filter capacitor group is connected the input of filter module, the output of filter module is connected first filter capacitor or the output of second filter capacitor group and common port ground connection.
2. A high frequency EMC filter circuit according to claim 1, characterized in that: the filtering module is a grounding magnetic ring or a grounding resistor.
3. A high frequency EMC filter circuit according to claim 2, characterized in that: the grounding magnetic ring is made of one or more of ferrite materials, iron powder core materials and magnetic powder core materials.
4. A high frequency EMC filter circuit according to claim 2, characterized in that: the inner diameter of the grounding magnetic ring is 3-5 mm.
5. A high frequency EMC filter circuit according to claim 2, characterized in that: the impedance of a single loop of the magnetic ring is more than 30 omega within the frequency of 10MHz-300 MHz.
6. A high frequency EMC filter circuit according to claim 2, characterized in that: the grounding resistor is an oxide film resistor or a metal film resistor.
7. A high frequency EMC filter circuit according to claim 2, characterized in that: the resistance value of the grounding resistor is 30-100 omega, and the rated power of the grounding resistor is larger than 2W.
8. A high frequency EMC filter circuit according to claim 1, characterized in that: the first filter capacitor group comprises two Y capacitors, one ends of the two Y capacitors are respectively connected with a mains supply zero line and a mains supply live line, and the other ends of the two Y capacitors are connected together and connected with the input end of the grounding module or the ground; the second filter capacitor group also comprises two Y capacitors, one ends of the two Y capacitors are respectively connected with the commercial power zero line and the commercial power live line, and the other ends of the two Y capacitors are connected together and connected with the input end or the ground of the filter module.
9. A high frequency EMC filter circuit according to claim 1, characterized in that: the common mode choke coil comprises a magnetic core and a coil, wherein the magnetic core is made of ferrite materials or amorphous materials, the coil is formed by sequential winding or butterfly winding when being a single-layer coil, a plurality of coil sections are formed by winding in sections when being a multi-layer coil, and the coil sections are insulated with the coil sections through resin plates.
10. A household appliance, characterized by: the household appliance comprises a high frequency EMC filter circuit as claimed in any one of claims 1 to 9.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201921843189.5U CN210985938U (en) | 2019-10-30 | 2019-10-30 | High-frequency EMC filter circuit and household appliance |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201921843189.5U CN210985938U (en) | 2019-10-30 | 2019-10-30 | High-frequency EMC filter circuit and household appliance |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111884500A (en) * | 2020-08-03 | 2020-11-03 | 中车青岛四方车辆研究所有限公司 | Method for suppressing common-mode conducted interference of vehicle-mounted charger |
| CN112303806A (en) * | 2020-10-19 | 2021-02-02 | 青岛海信日立空调系统有限公司 | Communication circuit and air conditioner |
| WO2023082771A1 (en) * | 2021-11-15 | 2023-05-19 | 一巨自动化装备（上海）有限公司 | Dc-terminal multistage filter structure, motor controller, and vehicle |
-
2019
- 2019-10-30 CN CN201921843189.5U patent/CN210985938U/en active Active
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111884500A (en) * | 2020-08-03 | 2020-11-03 | 中车青岛四方车辆研究所有限公司 | Method for suppressing common-mode conducted interference of vehicle-mounted charger |
| CN111884500B (en) * | 2020-08-03 | 2022-02-22 | 中车青岛四方车辆研究所有限公司 | Method for suppressing common-mode conducted interference of vehicle-mounted charger |
| CN112303806A (en) * | 2020-10-19 | 2021-02-02 | 青岛海信日立空调系统有限公司 | Communication circuit and air conditioner |
| CN112303806B (en) * | 2020-10-19 | 2023-11-17 | 青岛海信日立空调系统有限公司 | Communication circuit and air conditioner |
| WO2023082771A1 (en) * | 2021-11-15 | 2023-05-19 | 一巨自动化装备（上海）有限公司 | Dc-terminal multistage filter structure, motor controller, and vehicle |
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