DC end multistage filtering structure
Through the design of the DC-end multi-stage filter structure, combined with screw connections and PCBA boards, integrated fuses, and the use of magnetic rings and ferrite cores, the problems of large space occupation and inflexible layout of traditional filter components are solved, and efficient EMC effect is achieved in a limited space.
Patent Information
- Application Number
- CN202510418696.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-03
- Publication Date
- 2025-08-05
AI Technical Summary
Traditional EMC filtering components need to occupy a lot of space and the capacitor arrangement is inflexible, which affects the space utilization and EMC effect of the filtering components.
The DC-end multi-stage filtering structure is adopted, including a shell, high-voltage plug-in, film capacitor, primary filter fixture and secondary filter fixture. The flexible arrangement of capacitors is achieved through screw connections and PCBA boards, and fuses are integrated, combined with magnetic rings and ferrite cores for filtering to form a multi-stage filtering network.
Meet EMC level requirements in a limited space, save space and connection wiring harness length, improve the space utilization rate and EMC effect of filter components, and realize magneto-electric and thermal collaborative design.
Smart Images
Figure CN120433729A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of motor controllers, and in particular relates to a DC-end multi-stage filtering structure. Background Art
[0002] Electromagnetic compatibility (EMC) refers to the ability of a device or system to operate normally in its electromagnetic environment without causing unacceptable electromagnetic interference to anything in that environment. According to the EMC definition, electronic equipment must meet EMC design requirements. On the one hand, it must ensure a certain degree of immunity to electromagnetic interference from its environment, and on the other hand, the electromagnetic interference generated by the electronic equipment during operation must not exceed specified limits.
[0003] An automotive motor controller is a typical electronic device, equipped with connecting wiring harnesses, PCBs, power modules, capacitor modules, and other electronic components. An all-in-one controller typically includes an OBC, DC-DC converter, and PTC. When designing an EMC solution, the general approach is to place filtering devices such as magnetic rings at the DC input and three-phase output terminals, along with filtering components such as magnetic cores and capacitors in the DC path. To prevent spatial coupling of high and low voltages, metal shielding walls or shielding plates are installed for physical isolation, and grounding is also required in specific locations. Sufficient filtering components must be placed within a given envelope to meet EMC requirements, maximizing the filtering level.
[0004] When designing the EMC for the DC side of a controller, the traditional approach is to place multiple filtering components—such as filter capacitors of varying capacitance, magnetic rings, magnetic cores, and filter circuits—along the current path. However, traditional EMC filter components have several drawbacks: First, as separate components, the filter components require a certain amount of space to secure them. Second, the power and grounding of the capacitors used in the filter circuits are both soldered to the capacitor pins via copper busbars. This results in inflexible and limited capacitor placement, limiting the space available for the filter components. Summary of the Invention
[0005] In view of the above problems, the present invention proposes a DC-end multi-stage filter structure, comprising a housing, a high-voltage plug-in, a film capacitor, a primary filter fixing member and a secondary filter fixing member;
[0006] The positive and negative input terminals of the first-level filter fixture are connected to the high-voltage plug-in, and the positive and negative output terminals of the first-level filter fixture are connected to the positive and negative input terminals of the second filter fixture via screws; the positive and negative output terminals of the second filter fixture are connected to the positive and negative input terminals of the film capacitor via screws, and the positive and negative output terminals of the second filter fixture are connected to the positive and negative power-taking points, respectively, and the negative power-taking points are connected to the film capacitor via screws; the positive and negative output terminals of the film capacitor are connected to the external load;
[0007] The secondary filter fixing component includes a secondary filter PCBA board; the grounding point of the secondary filter PCBA board is connected to the shell by a screw; the positive power point of the secondary filter PCBA board is connected to the fuse input copper bar and the fuse output copper bar, and a fuse body is installed between the fuse input copper bar and the fuse output copper bar, and the fuse body is set in the positive pole circuit.
[0008] Furthermore, the primary filter component includes a primary housing, a primary filter PCBA board, a primary X capacitor and a primary Y capacitor; the primary filter PCBA board is installed inside the primary housing, and the primary housing is installed in the outer shell; the primary filter PCBA board is connected to the primary X capacitor and the primary Y capacitor, and the primary filter PCBA board is connected to a primary power copper bus and a primary grounding copper bus; the primary grounding copper bus is connected to the outer shell.
[0009] Furthermore, the secondary filter component also includes a secondary magnetic ring component, a secondary shell and a ferrite core component; the secondary magnetic ring component and the ferrite core component are both mounted on the secondary shell, and the secondary shell is mounted on the outer shell; a copper bar heat dissipation area is arranged between the secondary magnetic ring component and the ferrite core component; a thermal pad is installed between the copper bar heat dissipation area and the secondary shell; the positive and negative input ends of the secondary magnetic ring component are connected to the positive and negative output ends of the primary filter fixing component, and the positive and negative output ends of the secondary magnetic ring component are correspondingly connected to the positive and negative input ends of the film capacitor;
[0010] The secondary filter PCBA board is connected with the No. 1 secondary power copper busbar, the No. 1 secondary grounding copper busbar, the No. 2 secondary power copper busbar and the No. 2 secondary grounding copper busbar; the No. 1 secondary grounding copper busbar and the No. 2 secondary grounding copper busbar are connected to the casing.
[0011] Furthermore, the secondary magnetic ring component includes a magnetic ring body and a magnetic ring shell; the magnetic ring body is fixed in the magnetic ring shell through a potting process.
[0012] Furthermore, the ferrite core piece includes a first core and a second core; the first core and the second core form a closed loop by matching.
[0013] Furthermore, the secondary filter PCBA board includes a first channel and a second channel; the first channel includes a magnetic ring body, a No. 1 secondary power copper bus, a No. 1 secondary grounding copper bus, a No. 1 secondary X capacitor and a No. 1 secondary Y capacitor connected in sequence; the magnetic ring body passes through the magnetic ring housing and is connected to the No. 1 secondary power copper bus;
[0014] The second channel includes a No. 1 magnetic core, a No. 2 magnetic core, a No. 2 secondary power copper busbar, a No. 2 secondary grounding copper busbar, a No. 2 secondary X capacitor and a No. 2 secondary Y capacitor which are connected in sequence.
[0015] Furthermore, the first-level filter PCBA board is welded with the first-level X capacitor and the first-level Y capacitor through openings, and the first-level filter PCBA board is electrically connected with the first-level power copper bus and the first-level grounding copper bus through openings.
[0016] Furthermore, there is one first-level X capacitor and two first-level Y capacitors; the two first-level Y capacitors are respectively distributed on both sides of the first-level X capacitor.
[0017] Furthermore, there is one No. 1 secondary X capacitor and four No. 1 secondary Y capacitors; the four No. 1 secondary Y capacitors are divided into two groups and arranged on both sides of the No. 1 secondary X capacitor.
[0018] Furthermore, there are two No. 2 secondary X capacitors and four No. 2 secondary Y capacitors, and the four No. 2 secondary Y capacitors are divided into two groups and arranged on both sides of the two No. 2 secondary X capacitors.
[0019] Beneficial effects
[0020] The beneficial effects of the present invention compared to the prior art are as follows:
[0021] 1. This application utilizes a secondary filter PCBA for grounding, neatly arranging the multi-stage filter structure to reduce its footprint, ensuring that the EMC requirements for the controller's DC terminal are met within a limited space. Furthermore, the multi-stage filter structure integrates the fuse body directly onto the secondary filter fixture, saving space and wiring harness length.
[0022] 2. This application adopts a multi-band collaborative filtering framework of the magnetic ring body and the ferrite core body. The magnetic ring body processes high-frequency interference, and the ferrite core body forms a closed loop to suppress differential mode / common mode interference. The magnetic, electrothermal collaborative design is realized through the copper busbar heat dissipation area and thermal pad.
[0023] 3. This application forms a multi-order filtering network by setting the first channel and the second channel inside the secondary filtering PCBA board to cover broadband interference suppression.
[0024] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0026] Figure 1 It shows a schematic diagram of the overall structure of an embodiment of the present invention.
[0027] Figure 2a A top view of a primary filter fixture in an embodiment of the present invention is shown.
[0028] Figure 2b A top view of the primary filter PCBA board is shown with the primary filter fixing member removed in an embodiment of the present invention.
[0029] Figure 3 A schematic structural diagram of a secondary filter fixing member in an embodiment of the present invention is shown.
[0030] Figure 4 A schematic diagram of the internal structure of a secondary filter fixing component in an embodiment of the present invention is shown.
[0031] In the figure, 1. Primary filter fixture; 2. Secondary filter fixture; 3. Primary negative input terminal; 4. Plug-in negative terminal; 5. Secondary negative input terminal; 6. Primary negative output terminal; 7. Secondary positive input terminal; 8. Primary positive output terminal; 9. Fuse input busbar; 10. Fuse body; 11. Fuse output busbar; 12. Positive power point; 13. Secondary positive output terminal; 14. Negative power point; 15. Secondary negative output terminal; 16. Primary positive input terminal; 17. Plug-in positive terminal; 18. High-voltage plug-in; 19. Housing; 20. Grounding fixture.
[0032] 24. Primary filter PCBA board; 25. Primary power busbar; 26. Primary grounding busbar; 27. Primary X capacitor; 28. Primary Y capacitor; 29. Magnetic ring body; 30. Magnetic ring shell; 31. Copper busbar heat dissipation area; 32. No. 1 magnetic core; 33. No. 2 magnetic core; 34. Secondary filter PCBA board; 36. Thermal pad; 41. No. 1 and No. 2 power busbar; 42. No. 1 and No. 2 grounding busbar; 43. No. 2 and No. 2 power busbar; 44. No. 2 and No. 2 grounding busbar; 45. No. 1 and No. 2 X capacitor; 46. No. 1 and No. 2 Y capacitor; 47. No. 2 and No. 2 X capacitor; 48. No. 2 and No. 2 Y capacitor. DETAILED DESCRIPTION
[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.
[0034] This application provides a DC-end multi-stage filtering structure, referring to Figure 1 , including a housing 19, a high-voltage plug-in 18, a film capacitor, a primary filter fixing part 1 and a secondary filter fixing part 2;
[0035] The positive and negative input terminals of the primary filter fixture 1 are connected to the high-voltage plug-in 18, and the positive and negative output terminals of the primary filter fixture 1 are correspondingly connected to the positive and negative input terminals of the second filter fixture; the positive and negative output terminals of the second filter fixture are correspondingly connected to the positive and negative input terminals of the film capacitor, and the positive and negative output terminals of the second filter fixture are correspondingly connected to the positive power point 12 and the negative power point 14, and the negative power point 14 is connected to the film capacitor; the positive and negative output terminals of the film capacitor are connected to the external load;
[0036] The secondary filter fixture 2 includes a secondary filter PCBA board 34; the grounding point of the secondary filter PCBA board 34 is connected to the housing 19; the positive power point 12 of the secondary filter PCBA board 34 is connected to the fuse input copper bus 9 and the fuse output copper bus 11, and a fuse body 10 is installed between the fuse input copper bus 9 and the fuse output copper bus 11, and the fuse body 10 is set in the positive circuit.
[0037] The positive and negative input terminals of the first-level filter fixture 1 are referred to as the first-level positive input terminal 16 and the first-level negative input terminal 3 respectively; the positive and negative output terminals of the first-level filter fixture 1 are referred to as the first-level positive output terminal 8 and the first-level negative output terminal 6 respectively; the positive and negative terminals of the high-voltage plug-in 18 are referred to as the plug-in positive terminal 17 and the plug-in negative terminal 4 respectively; the positive and negative input terminals of the film capacitor are referred to as the capacitor positive input terminal and the capacitor negative input terminal respectively; the positive and negative output terminals of the second filter fixture are referred to as the second-level positive output terminal 13 and the second-level negative output terminal 15 respectively; the positive and negative input terminals of the second filter fixture are referred to as the second-level positive input terminal 7 and the second-level negative input terminal 5 respectively; the positive power supply position and the negative power supply position of the second-level filter PCBA board 34 are referred to as the positive power supply point 12 and the negative power supply point 14; the grounding point of the second-level filter PCBA board 34 is referred to as the grounding fixing point 20;
[0038] The primary positive input terminal 16 is screwed to the positive terminal 17 of the plug-in, and the primary negative input terminal 3 is screwed to the negative terminal 4 of the plug-in; the primary positive output terminal 8 is screwed to the secondary positive input terminal 7, and the primary negative output terminal 6 is screwed to the secondary negative input terminal 5; the secondary positive output terminal 13 is screwed to the positive input terminal of the capacitor, and the secondary negative output terminal 15 is screwed to the negative input terminal of the capacitor; the grounding fixing point 20 is screwed to the casing 19; the fuse input copper busbar 9 is connected to the positive power point 12 using a wiring harness; the copper busbar connection method in the primary filter fixture 1 and the secondary filter fixture 2 can be connected using laser welding.
[0039] All-in-one controllers typically include fuses. To ensure easy installation, reliable electrical safety, and connection to the wiring harness, a separate fuse mounting base is often required. To meet the EMC level requirements for the controller's DC input within a limited space, capacitor power and grounding are both implemented via a PCBA. This arrangement is unaffected by the orientation of the main copper busbars, saving space in the filter assembly. This PCBA solution reduces the number of grounding and power busbars, saving costs and reducing space. Finally, the fuse is integrated into the filter assembly's plastic housing, reducing the number of parts and installation space, and simplifying the installation process.
[0040] The present application uses a secondary filter PCBA board 34 for grounding and regularly arranges the multi-stage filter structure to reduce the spatial volume, thereby ensuring that the EMC level requirements of the controller DC end are met within a limited space; in addition, the multi-stage filter structure directly installs the fuse body 10 on the secondary filter fixture 2 in an integrated manner, saving space and the length of the connection harness.
[0041] In one embodiment of the present invention, referring to Figure 2a and Figure 2b The primary filter component includes a primary housing, a primary filter PCBA board 24, a primary X capacitor 27 and a primary Y capacitor 28; the primary filter PCBA board 24 is installed inside the primary housing, and the primary housing is installed in the outer shell 19; the primary filter PCBA board 24 is connected to the primary X capacitor 27 and the primary Y capacitor 28, and the primary filter PCBA board 24 is connected to a primary power copper bus 25 and a primary grounding copper bus 26; the primary grounding copper bus 26 is connected to the outer shell 19.
[0042] There is one first-level X capacitor 27 and two first-level Y capacitors 28 ; the two first-level Y capacitors 28 are respectively distributed on both sides of the first-level X capacitor 27 .
[0043] The first-level filter PCBA board 24 is welded to the first-level X capacitor 27 and the first-level Y capacitor 28 through openings, and the first-level filter PCBA board 24 is electrically connected to the first-level power copper bus 25 and the first-level grounding copper bus 26 through openings.
[0044] The primary housing is made of plastic; the primary filter PCBA board 24 is connected to a primary X capacitor 27 and two primary Y capacitors 28 via pins, and the whole is tightly arranged to save space; the primary filter PCBA board 24 has holes opened to solder to the pins of the primary X capacitor 27 and the primary Y capacitor 28, wherein the primary filter PCBA board 24 has two holes electrically connected to the primary power copper bus 25 and the primary grounding copper bus 26; the primary power copper bus 25 is respectively connected to the electrical connection points of the primary negative input terminal 3 and the primary positive input terminal 16 by welding, and the screws are locked to obtain power;
[0045] Caseless capacitors can be directly encapsulated in plastic shells, which are smaller and more compact.
[0046] In one embodiment of the present invention, referring to Figure 3 The secondary filter component further includes a secondary magnetic ring component, a secondary shell and a ferrite core component; the secondary magnetic ring component and the ferrite core component are both mounted on the secondary shell, and the secondary shell is mounted on the outer shell 19; a copper busbar heat dissipation area 31 is arranged between the secondary magnetic ring component and the ferrite core component; a thermal pad 36 is installed between the copper busbar heat dissipation area 31 and the secondary shell; the positive and negative input ends of the secondary magnetic ring component are connected to the positive and negative output ends of the primary filter fixture 1, and the positive and negative output ends of the secondary magnetic ring component are correspondingly connected to the positive and negative input ends of the film capacitor;
[0047] refer to Figure 4 The secondary filter PCBA board 34 is connected to the No. 1 secondary power copper bus 41, the No. 1 secondary grounding copper bus 42, the No. 2 secondary power copper bus 43 and the No. 2 secondary grounding copper bus 44; the No. 1 secondary grounding copper bus 42 and the No. 2 secondary grounding copper bus 44 are connected to the casing 19.
[0048] In one embodiment of the present invention, the secondary magnetic ring component includes a magnetic ring body 29 and a magnetic ring housing 30 ; the magnetic ring body 29 is fixed in the magnetic ring housing 30 through a potting process.
[0049] In one embodiment of the present invention, the ferrite core member includes a first magnetic core 32 and a second magnetic core 33 ; the first magnetic core 32 and the second magnetic core 33 cooperate to form a closed loop.
[0050] The magnetic ring body 29 is a nanocrystalline magnetic ring. The first magnetic core 32 is a ferrite I core, and the second magnetic core 33 is a ferrite E core. The magnetic ring body 29 is potted in a reserved groove in the magnetic ring housing 30. A copper busbar heat sink area 31 is located between the magnetic ring body 29, the first magnetic core 32, and the second magnetic core 33. This area dissipates heat from the secondary housing via a thermally conductive gel pad 36. The first and second magnetic cores 32, 33 form a closed circuit, which suppresses the differential and common-mode inductance generated by the copper busbar current.
[0051] The three-stage magnetic circuit combination of the magnetic ring body 29, the first magnetic core 32 and the second magnetic core 33: the magnetic ring body 29 handles high-frequency interference, the ferrite core forms a closed loop to suppress differential mode / common mode interference, and the magnetic, electrothermal coordinated design is achieved through the copper busbar heat dissipation area 31 and the thermal conductive gel pad.
[0052] The "inverted arrangement" of ferrite core components (layout below the electrodes) optimizes space utilization and is an unconventional core installation method.
[0053] In one embodiment of the present invention, the secondary filtering PCBA board 34 includes a first channel and a second channel; the first channel includes a magnetic ring body 29, a No. 1 secondary power copper bus 41, a No. 1 secondary grounding copper bus 42, a No. 1 secondary X capacitor 45 and a No. 1 secondary Y capacitor 46 connected in sequence; the magnetic ring body 29 passes through the magnetic ring shell 30 and is connected to the No. 1 secondary power copper bus 41; the second channel includes a No. 1 magnetic core 32, a No. 2 magnetic core 33, a No. 2 secondary power copper bus 43, a No. 2 secondary grounding copper bus 44, a No. 2 secondary X capacitor 47 and a No. 2 secondary Y capacitor 48 connected in sequence.
[0054] Through the dual-channel design of the secondary filtering PCBA board 34, a multi-order filtering network is formed to cover broadband interference suppression.
[0055] In one embodiment of the present invention, there is one first secondary X capacitor 45 and four first secondary Y capacitors 46 ; the four first secondary Y capacitors 46 are divided into two groups and arranged on both sides of the first secondary X capacitor 45 .
[0056] In one embodiment of the present invention, there are two second-level X capacitors 47 and four second-level Y capacitors 48 . The four second-level Y capacitors 48 are divided into two groups and arranged on both sides of the two second-level X capacitors 47 .
[0057] On the front side of the secondary filter fixture 2 (with Figure 4 For example, the secondary filter PCBA 34 connects to the secondary power busbar and the secondary grounding busbar via pins. Two channels are internally located within the secondary filter PCBA 34. The first channel connects the No. 1 secondary power busbar 41 and No. 1 secondary grounding busbar 42 behind the nanocrystalline magnetic core to a No. 1 secondary X capacitor 45 and four No. 1 secondary Y capacitors 46. The second channel connects the No. 2 secondary power busbar 43 and No. 2 secondary grounding busbar 44 behind the No. 1 and No. 2 magnetic cores 32 and 33 to two No. 2 secondary X capacitors 47 and four No. 2 secondary Y capacitors 48. By strategically positioning the power connection points, the ferrite core is positioned below the circuit, resulting in a compact secondary magnetic ring assembly. The secondary filter fixture 2 includes a fuse input busbar 9 and a fuse output busbar 11. In the positive line, a fuse body 10 is installed between the fuse input busbar 9 and the fuse output busbar 11, eliminating a fuse mounting base, saving material costs and installation space.
[0058] The EMC device in this application includes a magnetic ring body 29, a first magnetic core 32, a second magnetic core 33, and first-stage filter PCBA boards 24 and 34. The filtering structure comprises a first-stage filter fixture 1 and a second-stage filter fixture 2. The first-stage filter fixture 1 and the second-stage filter fixture 2 are injection-molded housings, with a plastic-coated copper busbar inside. The magnetic cores and filter PCBA boards are secured by glue potting, welding, and screw fastening.
[0059] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A DC-end multi-stage filter structure, characterized in that: It comprises a housing (19), a high-voltage plug-in unit (18), a film capacitor, a primary filter fixing unit (1) and a secondary filter fixing unit (2); The positive and negative input terminals of the first-level filter fixture (1) are connected to the high-voltage plug-in (18); the positive and negative output terminals of the first-level filter fixture (1) are correspondingly connected to the positive and negative input terminals of the second filter fixture; the positive and negative output terminals of the second filter fixture are correspondingly connected to the positive and negative input terminals of the film capacitor; the positive and negative output terminals of the second filter fixture are correspondingly connected to the positive power-taking point (12) and the negative power-taking point (14), and the negative power-taking point (14) is connected to the film capacitor; the positive and negative output terminals of the film capacitor are connected to an external load; The secondary filter fixing member (2) includes a secondary filter PCBA board (34); the grounding point of the secondary filter PCBA board (34) is connected to the housing (19); the positive electrode power point (12) of the secondary filter PCBA board (34) is connected to a fuse input copper bar (9) and a fuse output copper bar (11); a fuse body (10) is installed between the fuse input copper bar (9) and the fuse output copper bar (11); and the fuse body (10) is arranged in the positive electrode circuit.
2. A DC-end multi-stage filter structure according to claim 1, characterized in that: The primary filter component comprises a primary housing, a primary filter PCBA board (24), a primary X capacitor (27) and a primary Y capacitor (28); the primary filter PCBA board (24) is installed inside the primary housing, and the primary housing is installed in the housing (19); the primary filter PCBA board (24) is connected to the primary X capacitor (27) and the primary Y capacitor (28); the primary filter PCBA board (24) is connected to a primary power copper busbar (25) and a primary grounding copper busbar (26); the primary grounding copper busbar (26) is connected to the housing (19).
3. A DC-end multi-stage filter structure according to claim 2, characterized in that: The secondary filter component further comprises a secondary magnetic ring component, a secondary shell and a ferrite core component; the secondary magnetic ring component and the ferrite core component are both mounted on the secondary shell, and the secondary shell is mounted on the outer shell (19); a copper bar heat dissipation area (31) is arranged between the secondary magnetic ring component and the ferrite core component; a thermal pad (36) is installed between the copper bar heat dissipation area (31) and the secondary shell; the positive and negative input ends of the secondary magnetic ring component are connected to the positive and negative output ends of the primary filter fixing component (1), and the positive and negative output ends of the secondary magnetic ring component are connected to the positive and negative input ends of the film capacitor; The secondary filtering PCBA board (34) is connected to a No. 1 secondary power copper busbar (41), a No. 1 secondary grounding copper busbar (42), a No. 2 secondary power copper busbar (43) and a No. 2 secondary grounding copper busbar (44); the No. 1 secondary grounding copper busbar (42) and the No. 2 secondary grounding copper busbar (44) are connected to the housing (19).
4. A DC-end multi-stage filter structure according to claim 3, characterized in that: The secondary magnetic ring component comprises a magnetic ring body (29) and a magnetic ring shell (30); the magnetic ring body (29) is fixed in the magnetic ring shell (30) through a potting process.
5. A DC-end multi-stage filter structure according to claim 4, characterized in that: The ferrite core piece comprises a first magnetic core (32) and a second magnetic core (33); the first magnetic core (32) and the second magnetic core (33) form a closed loop by matching.
6. A DC-end multi-stage filter structure according to claim 5, characterized in that: The secondary filtering PCBA board (34) includes a first channel and a second channel; the first channel includes a magnetic ring body (29), a No. 1 secondary power copper busbar (41), a No. 1 secondary grounding copper busbar (42), a No. 1 secondary X capacitor (45) and a No. 1 secondary Y capacitor (46) connected in sequence; the magnetic ring body (29) passes through the magnetic ring housing (30) and is connected to the No. 1 secondary power copper busbar (41); The second channel includes a No. 1 magnetic core (32), a No. 2 magnetic core (33), a No. 2 secondary power copper busbar (43), a No. 2 secondary grounding copper busbar (44), a No. 2 secondary X capacitor (47) and a No. 2 secondary Y capacitor (48) connected in sequence.
7. The DC-end multi-stage filter structure according to claim 2, characterized in that: The first-level filter PCBA board (24) is welded to the first-level X capacitor (27) and the first-level Y capacitor (28) through openings, and the first-level filter PCBA board (24) is electrically connected to the first-level power copper bus (25) and the first-level grounding copper bus (26) through openings.
8. The DC-end multi-stage filter structure according to claim 7, characterized in that: There is one first-level X capacitor (27) and two first-level Y capacitors (28); the two first-level Y capacitors (28) are respectively distributed on both sides of the first-level X capacitor (27).
9. The DC-end multi-stage filter structure according to claim 6, characterized in that: There is one No. 1 secondary X capacitor (45) and four No. 1 secondary Y capacitors (46); the four No. 1 secondary Y capacitors (46) are divided into two groups and arranged on both sides of the No. 1 secondary X capacitor (45).
10. The DC-end multi-stage filter structure according to claim 6, characterized in that: There are two second-level X capacitors (47) and four second-level Y capacitors (48). The four second-level Y capacitors (48) are divided into two groups and arranged on both sides of the two second-level X capacitors (47).