Electromagnetic compatibility filter circuit of three-phase position-free direct-current fan

Abstract

The invention provides an electromagnetic compatibility filter circuit of a three-phase positionless direct-current fan, and relates to the technical field of conduction and radiation suppression of the three-phase positionless direct-current fan, and the circuit comprises a three-stage differential-mode filter capacitor, a first-stage common-mode capacitor and a first-stage common-mode inductor which are connected with a power supply in parallel, the three-stage differential-mode filter capacitor is used for filtering differential-mode interference signals in a circuit, the common-mode capacitor and the common-mode inductor are used for providing a low-impedance loop for common-mode interference signals and filtering common-mode interference signals, and the three-stage differential-mode filter capacitor comprises a first differential-mode filter capacitor, a second differential-mode filter capacitor and a third differential-mode filter capacitor group. The first-stage common-mode capacitor comprises a first common-mode filter capacitor, and the first-stage common-mode inductor comprises a first common-mode inductor. According to the filter circuit, a three-stage differential mode circuit and a two-stage common mode circuit are combined, and the filter circuit can play a good role in inhibiting differential mode interference signals and common mode interference signals generated in a three-phase position-free direct-current fan power supply and a commutation circuit.

Description

Technical Field

[0001] The invention relates to the technical field of conduction and radiation suppression of a three-phase positionless DC fan, and in particular provides an electromagnetic compatibility filter circuit for a three-phase positionless DC fan. Background Art

[0002] Due to the small size, limited space and inability to be completely shielded of three-phase non-position DC fans, during the operation of the DC fans, their power circuits and drive circuits will interfere with external devices, mainly in the form of conducted interference and radiated interference. Therefore, it is difficult to rectify the electromagnetic compatibility of three-phase non-position DC fans.

[0003] Currently, the electromagnetic compatibility circuit for three-phase non-position DC fans is complex, large in size, and inconvenient to use. Summary of the invention

[0004] The purpose of the present application is to provide an electromagnetic compatibility filter circuit for a three-phase positionless DC fan, which realizes electromagnetic compatibility in a limited space by combining a three-stage differential mode circuit and a two-stage common mode circuit.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A three-phase non-position DC fan electromagnetic compatibility filter circuit, the circuit includes a three-stage differential mode filter capacitor, a first-stage common mode capacitor and a first-stage common mode inductor connected in parallel with a power supply,

[0007] The three-level differential mode filter capacitor is used to filter out the differential mode interference signal in the circuit. The common mode capacitor and common mode inductor are used to provide a low impedance loop for the common mode interference signal to filter out the common mode interference signal.

[0008] The three-stage differential mode filter capacitor includes a first differential mode filter capacitor, a second differential mode filter capacitor and a third differential mode filter capacitor group; the first-stage common mode capacitor includes a first common mode filter capacitor; and the first-stage common mode inductor includes a first common mode inductor.

[0009] The three-phase positionless DC fan electromagnetic compatibility filter circuit provided by the present invention also has the following characteristics: the first differential mode filter capacitor is connected across the positive input terminal and the negative input terminal of the power line, and the first differential mode filter capacitor is a uF grade ceramic capacitor.

[0010] The three-phase positionless DC fan electromagnetic compatibility filter circuit provided by the present invention also has the following characteristics: the first common-mode filter capacitor is connected across the positive input end of the power line, the shell, the negative input end, and the shell; the common end of the first common-mode filter capacitor is connected to the shell; and the first common-mode filter capacitor is a pF-level capacitor.

[0011] The three-phase positionless DC fan electromagnetic compatibility filter circuit provided by the present invention also has the following characteristics: the second differential mode filter capacitor is connected across the positive input terminal and the negative input terminal of the power line, and the second differential mode filter capacitor is a pF level capacitor.

[0012] The electromagnetic compatibility filter circuit of the three-phase positionless DC fan provided by the present invention also has the following characteristics: the first common-mode inductor is placed after the field-effect transistor for anti-reverse operation, the first common-mode inductor is connected across the positive input terminal and the negative input terminal of the power line, and the first common-mode inductor is selected according to the power of the three-phase fan.

[0013] The three-phase positionless DC fan electromagnetic compatibility filter circuit provided by the present invention also has the following characteristics: the third differential mode capacitor group is connected across the positive input terminal and the negative input terminal of the power line, and the third differential mode capacitor group includes an electrolytic capacitor and a ceramic capacitor in parallel, the electrolytic capacitor is a uF grade electrolytic capacitor, and the ceramic capacitor is a pF grade ceramic capacitor.

[0014] Beneficial Effects

[0015] Compared with the prior art, the present invention has the following beneficial effects: the three-phase positionless DC fan filter circuit of the present invention is mainly used for small and medium-sized brushless DC fans whose shell material is metal. The filter circuit adopts a combination of a three-stage differential mode circuit and a two-stage common mode circuit to achieve the suppression of CE102 and RE102 in a limited space. The filter circuit can play a good suppression role for the differential mode interference signal and common mode interference signal generated in the power supply and commutation circuit of the three-phase positionless DC fan, and can solve the problems of CE102 and RE102 of the three-phase positionless fan. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 It is a structural diagram of the three-phase positionless DC fan filter circuit of the present application.

[0018] In the figure: ①: first differential mode filter capacitor; ②: first common mode filter capacitor; ③: second differential mode filter capacitor; ④: first common mode inductor; ⑤: third differential mode capacitor group. DETAILED DESCRIPTION

[0019] The present application is further described in detail below in conjunction with the accompanying drawings and examples, but it should be noted that these implementation methods are not limitations of the present application, and equivalent changes or substitutions in functions, methods, or structures made by ordinary technicians in the field based on these implementation methods are all within the scope of protection of the present application.

[0020] In the description of the embodiments of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the creation of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the creation of the present application.

[0021] In addition, the terms "first", "second", "third", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the invention of this application, unless otherwise specified, the meaning of "plurality" is two or more.

[0022] The terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention of this application can be understood by specific circumstances.

[0023] like Figure 1 As shown, the present application provides an electromagnetic compatibility filter circuit for a three-phase non-position DC fan, the circuit comprising a three-stage differential mode filter capacitor, a first-stage common mode capacitor and a first-stage common mode inductor connected in parallel with a power supply,

[0024] The three-level differential mode filter capacitor is used to filter out the differential mode interference signal in the circuit. The common mode capacitor and common mode inductor are used to provide a low impedance loop for the common mode interference signal to filter out the common mode interference signal.

[0025] The three-stage differential mode filter capacitor includes a first differential mode filter capacitor ①, a second differential mode filter capacitor ③ and a third differential mode filter capacitor group ⑤, the first-stage common mode capacitor includes a first common mode filter capacitor ②, and the first-stage common mode inductor includes a first common mode inductor ④.

[0026] In some embodiments, the first differential mode filter capacitor ① is connected across the positive input terminal and the negative input terminal of the power line, and the first differential mode filter capacitor ① is a uF-level ceramic capacitor. There is no electrical connection between the common end of the common mode capacitor and the DC fan housing, and the capacitor can be a ceramic capacitor with a larger capacitance, preferably 10uF.

[0027] In some embodiments, the first common-mode filter capacitor ② is connected across the positive input terminal of the power line, the housing, the negative input terminal, and the housing. The common terminal of the first common-mode filter capacitor ② is connected to the housing. The first common-mode filter capacitor ② is a pF-level capacitor, preferably 104pF.

[0028] In some embodiments, the second differential mode filter capacitor ③ is connected across the positive input terminal and the negative input terminal of the power line, and the second differential mode filter capacitor ③ is a pF level capacitor, preferably 104pF.

[0029] In some embodiments, the first common mode inductor ④ is placed after the field effect tube for anti-reverse operation, the first common mode inductor ④ is connected across the positive input terminal and the negative input terminal of the power line, and the first common mode inductor ④ is selected according to the power of the three-phase fan, preferably 100uH.

[0030] In some embodiments, the third differential mode capacitor group ⑤ is connected across the positive input terminal and the negative input terminal of the power line, and the third differential mode capacitor group ⑤ includes an electrolytic capacitor and a ceramic capacitor in parallel, the electrolytic capacitor is a uF grade electrolytic capacitor, preferably 100uF; the ceramic capacitor is a pF grade ceramic capacitor, preferably 104pF.

[0031] The three-phase positionless DC fan filter circuit provided in the above embodiment is mainly used for small and medium-sized brushless DC fans whose shell material is metal. The filter circuit adopts a combination of a three-stage differential mode circuit and a two-stage common mode circuit to achieve the suppression of CE102 and RE102 in a limited space. The filter circuit can be arbitrarily combined according to the actual electromagnetic compatibility of the DC fan and is not limited to the circuit structure. For the differential mode interference signal and common mode interference signal generated in the power supply and commutation circuit of the three-phase positionless DC fan, the filter circuit is simple in form and can play a good suppression role, which can solve the problems of CE102 and RE102 of the three-phase positionless fan.

[0032] The above is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application. The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present application, and these improvements and variations should also be regarded as the protection scope of the present application.

Claims

1. A three-phase non-position DC fan electromagnetic compatibility filter circuit, characterized in that: The circuit includes three-level differential mode filter capacitors, one-level common mode capacitors and one-level common mode inductors connected in parallel with the power supply. The three-stage differential mode filter capacitor is used to filter out the differential mode interference signal in the circuit. The common mode capacitor and common mode inductor are used to provide a low impedance loop for the common mode interference signal to filter out the common mode interference signal. The three-stage differential mode filter capacitor includes a first differential mode filter capacitor, a second differential mode filter capacitor and a third differential mode filter capacitor group, the first-stage common mode capacitor includes a first common mode filter capacitor, and the first-stage common mode inductor includes a first common mode inductor.

2. The electromagnetic compatibility filter circuit of the three-phase non-position DC fan according to claim 1 is characterized in that: The first differential mode filter capacitor is connected across the positive input terminal and the negative input terminal of the power line, and the first differential mode filter capacitor is a uF grade ceramic capacitor.

3. The electromagnetic compatibility filter circuit of the three-phase non-position DC fan according to claim 1 is characterized in that: The first common-mode filter capacitor is connected across the positive input end of the power line, the housing, the negative input end, and the housing. The common end of the first common-mode filter capacitor is connected to the housing. The first common-mode filter capacitor is a pF-level capacitor.

4. The electromagnetic compatibility filter circuit of the three-phase non-position DC fan according to claim 1 is characterized in that: The second differential mode filter capacitor is connected across the positive input terminal and the negative input terminal of the power line, and the second differential mode filter capacitor is a pF level capacitor.

5. The electromagnetic compatibility filter circuit of the three-phase non-position DC fan according to claim 1 is characterized in that: The first common-mode inductor is placed after the field effect transistor for anti-reverse operation, the first common-mode inductor is connected across the positive input terminal and the negative input terminal of the power line, and the first common-mode inductor is selected according to the power of the three-phase fan.

6. The electromagnetic compatibility filter circuit of the three-phase non-position DC fan according to claim 1 is characterized in that: The third differential mode capacitor group is connected across the positive input terminal and the negative input terminal of the power line. The third differential mode capacitor group includes an electrolytic capacitor and a ceramic capacitor connected in parallel. The electrolytic capacitor is a uF-level electrolytic capacitor, and the ceramic capacitor is a pF-level ceramic capacitor.

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