EMC filter circuit and household electrical appliance

Abstract

The utility model provides an EMC filter circuit and a household electrical appliance, and the EMC filter circuit comprises a voltage adjusting module which is used for connecting a live wire and a zero wire of commercial power and adjusting the output voltage; the two input ends of the selection module are connected with the two output ends of the voltage regulation module, and the selection module is used for selecting the output voltage; the filtering module comprises a surge anti-interference circuit, a first filtering circuit and a second filtering circuit; the surge anti-interference circuit is used for surge anti-interference; the first filter circuit is used for suppressing high-frequency noise in an electromagnetic interference signal received by the input end; the two input ends of the second filter circuit are connected with the two output ends of the first filter circuit respectively, and the second filter circuit is used for suppressing common-mode interference and differential-mode interference of input electromagnetic interference signals. The EMC filter circuit provided by the utility model can adjust the voltage input into a corresponding electric appliance, so as to stabilize the input voltage of the electric appliance, and enable the electric appliance to pass an EMC test more easily.

Description

Technical Field

[0001] The embodiments of the present disclosure relate to the technical field of household appliances, and in particular to an EMC filter circuit and a household appliance. Background Art

[0002] Electromagnetic compatibility (EMC) refers to the ability of a device to operate normally in the same electromagnetic environment without being affected by interference from other devices, while also ensuring that no interference affects the operation of other devices. With the rapid development of information technology, the number of electronic devices in users' homes is increasing, and EMC requirements for these devices are becoming increasingly stringent. Each country or region has strict EMC standards for electronic information products.

[0003] Currently, household appliances such as blenders, refrigerators, and clothes drying racks lack filter modules, making EMC testing difficult. This is especially true in remote, cold regions, where voltage is often unstable. EMC testing is complex and can result in inaccurate results. Utility Model Content

[0004] The purpose of the embodiments of the present disclosure is to provide an EMC filter circuit and a household appliance, thereby solving the aforementioned problems existing in the prior art.

[0005] In order to achieve the above objectives, the technical solutions adopted in the embodiments of the present disclosure are as follows:

[0006] In one aspect, an embodiment of the present disclosure provides an EMC filter circuit, the EMC filter circuit comprising: a voltage regulating module, a selection module, and a filter module, the filter module being configured to connect to a power source of a corresponding electrical appliance;

[0007] The voltage regulating module is used to connect the live wire and the neutral wire of the mains electricity to regulate the output voltage;

[0008] The two input terminals of the selection module are connected to the two output terminals of the voltage regulation module for selecting the output voltage;

[0009] The filtering module includes: a surge protection circuit, a first filtering circuit and a second filtering circuit:

[0010] The two input terminals of the surge immunity circuit are respectively connected to the two output terminals of the selected module, and the surge immunity circuit is used for surge immunity;

[0011] The first filter circuit is connected in parallel with the surge immunity circuit, and its two input terminals are respectively connected to the two output terminals of the selected module, and the first filter circuit is used to suppress high-frequency noise in the electromagnetic interference signal received at the input terminal;

[0012] The two input ends of the second filter circuit are respectively connected to the two output ends of the first filter circuit. The second filter circuit is used to suppress common-mode and differential-mode interference of the input electromagnetic interference signal.

[0013] Exemplarily, the voltage regulation module includes: a transformer for increasing or decreasing the mains voltage, the transformer including: a primary winding and a secondary winding, the two ends of the primary winding are respectively used to connect the live wire and the neutral wire of the mains, and the secondary winding is provided with at least two groups of output ends, each group of output ends is respectively connected to the selected module.

[0014] Exemplarily, the selected module includes: a multi-stage switch, each input end of the multi-stage switch is respectively connected to each output end of the secondary winding, the multi-stage switch has multiple groups of output ends, and each group of output ends is respectively connected to two input ends of the filtering module.

[0015] Exemplarily, the surge protection circuit includes: a varistor, wherein two ends of the varistor are respectively connected to two output ends of the selected module.

[0016] Exemplarily, the surge protection circuit further includes: a heating component connected in parallel with the varistor, the heating component including: a current limiting resistor and a heating wire connected in series, and two ends of the heating component are respectively connected to the two output ends of the selected module;

[0017] The heating wire is wound around the varistor.

[0018] Exemplarily, the first filtering circuit includes: a first capacitor, a resistor and a common-mode inductor connected in parallel; the two ends of the first capacitor and the resistor and the two input ends of the common-mode inductor are respectively connected to the two output ends of the selected module, and the two output ends of the common-mode inductor are respectively connected to the second filtering circuit.

[0019] Exemplarily, the second filtering circuit includes: a second capacitor and a fourth capacitor and a fifth capacitor connected in series, wherein the second capacitor is connected in parallel with the fourth capacitor and the fifth capacitor connected in series and are respectively connected to two output ends of the common-mode inductor;

[0020] The fourth capacitor and the fifth capacitor are grounded.

[0021] Another aspect of the embodiments of the present disclosure provides a household appliance, which includes: the EMC filter circuit as described above.

[0022] The beneficial effects of the embodiments of the present disclosure are:

[0023] The EMC filter circuit of the embodiment of the present disclosure solves the problem of adjusting the voltage input to the corresponding electrical appliance to adapt to the unstable voltage in remote areas, while making it easier for the electrical appliance to pass the EMC test. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the structure of an EMC filter circuit proposed in an embodiment of the present disclosure;

[0025] Figure 2 1 is a schematic structural diagram of a transformer in an EMC filter circuit according to an embodiment of the present disclosure;

[0026] Figure 3 1 is a schematic structural diagram of a filter module in an EMC filter circuit according to an embodiment of the present disclosure;

[0027] Figure 4 1 is a schematic structural diagram of a surge immunity circuit in a filter module in an EMC filter circuit according to an embodiment of the present disclosure;

[0028] Figure 5 1 is a schematic structural diagram of a first filter circuit in a filter module in an EMC filter circuit according to an embodiment of the present disclosure;

[0029] Figure 6 3 is a schematic structural diagram of the second filter circuit in the filter module in the EMC filter circuit of an embodiment of the present disclosure. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the embodiments of the present disclosure more clear, the embodiments of the present disclosure are further described in detail below with reference to the accompanying drawings. It should be understood that the specific implementation methods described herein are only used to explain the embodiments of the present disclosure and are not intended to limit the embodiments of the present disclosure.

[0031] like Figure 1 and Figure 3As shown, an embodiment of the present disclosure provides an EMC filter circuit, which includes: a voltage regulation module 1, a selection module 2, and a filter module 3. The filter module 3 is used to connect to the power supply 4 of the corresponding electrical appliance; the voltage regulation module 1 is used to connect the live wire and the neutral wire of the mains power supply to regulate the output voltage; the two input ends of the selection module 2 are connected to the two output ends of the voltage regulation module 1 to select the output voltage; the filter module 3 includes: a surge suppression circuit 31, a first filter circuit 32, and a second filter circuit 33: the two input ends of the surge suppression circuit 31 are respectively connected to the two output ends of the selection module 2, and the surge suppression circuit 31 is used for surge suppression; the first filter circuit 32 is connected in parallel with the surge suppression circuit 31, and its two input ends are respectively connected to the two output ends of the selection module 2. The first filter circuit 32 is used to suppress high-frequency noise in the electromagnetic interference signal received at the input end; the two input ends of the second filter circuit 33 are respectively connected to the two output ends of the first filter circuit 32, and the second filter circuit is used to suppress common-mode and differential-mode interference of the input electromagnetic interference signal.

[0032] The EMC filter circuit of the disclosed embodiment is suitable for use in remote, cold regions, where voltage instability is common year-round. This can affect the EMC test results of household appliances. Therefore, the disclosed embodiment adds a voltage regulation module, a selection module, and a filtering module to the household appliance. The voltage regulation module and selection module are used to adjust the input voltage of the household appliance, while the filtering module is used for filtering.

[0033] The voltage regulation module can increase or decrease the output voltage. The selection module is integrated with the voltage regulation module to determine the specific output voltage. The selection module can control the output voltage through multiple gears. The first filter circuit is mainly used to suppress high-frequency noise in the electromagnetic interference signal received at the input terminal. The first filter circuit can also suppress differential mode interference. The filter module also includes a fuse F101 connected to the neutral line output terminal of the selection module.

[0034] like Figure 2 As shown, the voltage regulation module includes: a transformer for increasing or decreasing the mains voltage, the transformer including: a primary winding and a secondary winding, the two ends of the primary winding are respectively used to connect the live wire and the neutral wire of the mains, and the secondary winding is provided with at least two groups of output ends, each group of output ends is respectively connected to the selected module.

[0035] The transformer of the disclosed embodiment achieves boosting and lowering of the mains voltage by providing output terminals at different coil turns of the secondary winding. The secondary winding has a common output terminal, and at least two other output terminals, each corresponding to a coil with a different number of turns, form at least two groups of output terminals with the common output terminal.

[0036] like Figure 2 As shown, the selected module includes: a multi-stage switch, each input end of the multi-stage switch is respectively connected to each output end of the secondary winding, the multi-stage switch has multiple groups of output ends, and each group of output ends is respectively connected to the two input ends of the filtering module.

[0037] The multi-stage switch is provided with multiple switches, each of which has an input terminal connected to a corresponding output terminal of the transformer. Two output terminals of each switch form a group of output terminals, and each group of output terminals can share a single output terminal. By controlling the corresponding switch or gear position, the output terminal group is adjusted to adjust the output voltage.

[0038] like Figure 4 As shown, the surge protection circuit includes: a varistor, and two ends of the varistor are respectively connected to the two output ends of the selected module.

[0039] A fuse F101 is provided between the varistor and the selected module, and the varistor ZR101 plays a role in anti-surge.

[0040] like Figure 4 As shown, the surge protection circuit 31 further includes: a heating component connected in parallel with the varistor, the heating component including: a current limiting resistor R1 and a heating wire R2 connected in series, the two ends of the heating component are respectively connected to the two output ends of the selected module; the heating wire is wound around the varistor.

[0041] In the embodiment of the present disclosure, conventional varistors can be selected. In order to make the varistor adapt to the cold environment in remote areas, a heating wire is further provided to maintain the working environment temperature of the varistor and extend the service life of the varistor.

[0042] For example, in some pastoral areas, herders use refrigerators and other electrical appliances when setting up tents outdoors. Sometimes the outdoor temperature is low. At this time, the electrical appliances use the EMC filter circuit of the embodiment of the present disclosure to enable the electrical appliances to better adapt to the external environment.

[0043] like Figure 5 As shown, the first filtering circuit 32 includes: a first capacitor, a resistor and a common-mode inductor connected in parallel; the two ends of the first capacitor and the resistor and the two input ends of the common-mode inductor are respectively connected to the two output ends of the selected module, and the two output ends of the common-mode inductor are respectively connected to the second filtering circuit.

[0044] The first capacitor CX102 of the disclosed embodiment has two ends connected to the two output ends of the selected module, specifically, a set of output ends of the multi-stage switch. The first capacitor CX102 has the function of suppressing differential mode interference. Here, two series resistors are provided as a first discharge resistor R11 and a second discharge resistor R8, R11 and R8 respectively. The first capacitor CX102 and the common-mode inductor L101 play a filtering role, mainly for suppressing high-frequency noise in the electromagnetic interference signal received at the input end.

[0045] like Figure 6 As shown, the second filtering circuit 33 includes: a second capacitor and a fourth capacitor and a fifth capacitor connected in series. The second capacitor is connected in parallel with the fourth capacitor and the fifth capacitor connected in series and are respectively connected to the two output ends of the common-mode inductor; the fourth capacitor and the fifth capacitor are grounded.

[0046] The second filter circuit consists of a second capacitor CX103, and a fourth capacitor CY1 and a fifth capacitor CY2 connected in series. The second capacitor CX103 suppresses differential-mode interference, while the fourth and fifth capacitors CY1 and CY2 are grounded, suppressing common-mode interference. The first and second filter circuits perform filtering functions.

[0047] The inductance of the common-mode inductor L101 and the capacitance of the first capacitor CX102 and the second capacitor CX103 can be changed according to different products to meet EMC requirements.

[0048] Many household appliances in remote and cold areas have unstable circuits and are difficult to pass EMC tests. By adding this EMC filter circuit, most appliances can pass EMC tests, greatly improving development efficiency and success rate. In addition, it makes household appliances more adaptable to the environment in remote and cold areas.

[0049] Another aspect of the embodiments of the present disclosure provides a household appliance, which includes: the EMC filter circuit as described above.

[0050] The above is only a preferred implementation of the embodiment of the present disclosure. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the embodiment of the present disclosure. These improvements and modifications should also be considered within the scope of protection of the embodiment of the present disclosure.

Claims

1. An EMC filter circuit, characterized in that: The EMC filter circuit includes: a voltage regulation module, a selection module and a filter module, wherein the filter module is used to connect to the power supply of the corresponding electrical appliance; The voltage regulating module is used to connect the live wire and the neutral wire of the mains electricity to regulate the output voltage; The two input terminals of the selection module are connected to the two output terminals of the voltage regulation module for selecting the output voltage; The filtering module includes: a surge protection circuit, a first filtering circuit and a second filtering circuit: The two input terminals of the surge immunity circuit are respectively connected to the two output terminals of the selected module, and the surge immunity circuit is used for surge immunity; The first filter circuit is connected in parallel with the surge immunity circuit, and its two input terminals are respectively connected to the two output terminals of the selected module, and the first filter circuit is used to suppress high-frequency noise in the electromagnetic interference signal received at the input terminal; The two input ends of the second filter circuit are respectively connected to the two output ends of the first filter circuit. The second filter circuit is used to suppress common-mode and differential-mode interference of the input electromagnetic interference signal.

2. The circuit according to claim 1, wherein: The voltage regulation module includes: a transformer for increasing or decreasing the mains voltage, the transformer including: a primary winding and a secondary winding, the two ends of the primary winding are respectively used to connect the live wire and the neutral wire of the mains, and the secondary winding is provided with at least two groups of output ends, each group of output ends is respectively connected to the selected module.

3. The circuit according to claim 2, characterized in that The selected module includes: a multi-stage switch, each input end of the multi-stage switch is respectively connected to each output end of the secondary winding, the multi-stage switch has multiple groups of output ends, and each group of output ends is respectively connected to two input ends of the filtering module.

4. The circuit according to any one of claims 1 to 3, characterized in that The surge protection circuit includes a varistor, and two ends of the varistor are respectively connected to two output ends of the selected module.

5. The circuit according to claim 4, characterized in that The surge protection circuit further includes: a heating component connected in parallel with the varistor, the heating component including: a current limiting resistor and a heating wire connected in series, and two ends of the heating component are respectively connected to the two output ends of the selected module; The heating wire is wound around the varistor.

6. The circuit according to any one of claims 1 to 3, characterized in that The first filtering circuit includes: a first capacitor, a resistor and a common-mode inductor connected in parallel; the two ends of the first capacitor and the resistor and the two input ends of the common-mode inductor are respectively connected to the two output ends of the selected module, and the two output ends of the common-mode inductor are respectively connected to the second filtering circuit.

7. The circuit according to claim 6, characterized in that The second filtering circuit includes: a second capacitor and a fourth capacitor and a fifth capacitor connected in series, wherein the second capacitor is connected in parallel with the fourth capacitor and the fifth capacitor connected in series and are respectively connected to two output ends of the common-mode inductor; The fourth capacitor and the fifth capacitor are grounded.

8. A household appliance, characterized in that: The household appliance comprises: the EMC filter circuit according to any one of claims 1 to 7.

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