Integrated structure of EMC filter and DC capacitor of motor controller

Abstract

The utility model discloses an integrated structure of an EMC filter and a DC capacitor of a motor controller, which is characterized in that an anode busbar and a cathode busbar clamp a capacitor to form a strip-shaped capacitor assembly, one side of the capacitor assembly is provided with a DC output anode copper bar and a DC output cathode copper bar, and the other side of the capacitor assembly is provided with a DC input anode copper bar and a DC input cathode copper bar; a magnetic ring is arranged on the side face of the capacitor assembly, the DC input positive pole copper bar and the DC input negative pole copper bar penetrate through the magnetic ring, and the capacitor assembly and the magnetic ring are fixed in the insulation injection molding support. According to the integrated structure, through the integrated design of the magnetic rings, the XY capacitors and the positive and negative copper bars, differential-mode and common-mode components can be well suppressed, and the ever-increasing EMC level requirement is met; meanwhile, the size of the controller is reduced to the maximum extent, the weight of the controller is reduced, the development cost is reduced, and the requirements of higher integration level and higher reliability of the electric drive system are met.

Description

Technical Field

[0001] This utility model relates to the field of EMC filters and DC capacitor integration technology for new energy vehicle motor controllers. Background Technology

[0002] The electric drive system is a core component of new energy vehicles, mainly consisting of the motor, motor control unit, and reducer. With continuous technological advancements, electric drive systems are facing demands for higher integration and greater reliability.

[0003] In recent years, new energy drive systems have rapidly developed towards high-voltage platformization and SiC power transistors. Due to the presence of parasitic parameters and the high-frequency switching of switching devices in switching power supplies, significant common-mode and differential-mode interference is generated at the input. To mitigate and suppress the harmful effects of this electromagnetic interference on electronic systems, hardware engineers have added X capacitors and Y capacitors to the circuit design. Magnetic rings (generally made of ferrite materials such as Ni-Zn) also have a good suppression effect on high-frequency noise. Multiple X capacitors, Y capacitors, and magnetic rings connected in series and parallel are called filter components.

[0004] In motor controllers, the DC power from the battery pack serves as the input power and needs to be connected to the motor controller via a DC bus. This connection is called DC-LINK or DC support, and the capacitor used in this connection is called the bus capacitor, support capacitor, or DC-LINK capacitor. Because the motor controller receives very high effective or peak pulse currents from the battery pack, it also generates very high pulse voltages on the DC support, which the motor controller may find difficult to withstand. Therefore, a bus capacitor is needed to attenuate the peak voltage on the bus and absorb the high pulse current at the bus terminal.

[0005] Most motor controllers on the market currently use a filter component and a DC-L INC capacitor at the DC input terminal to suppress high current interference and improve EMC performance. For example, the published document with announcement number CN1530975A, publication date of 2004-09-22, and patent title "A Capacitor and Filter Assembly for Eliminating High-Frequency Electromagnetic Interference in High-Voltage Lines" discloses a capacitor and filter assembly for eliminating high-frequency electromagnetic interference in high-voltage lines. It uses special chemical raw materials such as barium carbonate, strontium carbonate, and calcium carbonate as the main components. These materials are mixed, ball-milled, dried, and pre-fired. Then, trace additives and a certain proportion of binder are added, followed by ball milling, spray drying granulation, and dry pressing into a circular ring-shaped blank. Finally, firing and electrode preparation are carried out to produce a ceramic capacitor. Alternatively, a double-ring ceramic capacitor is used as the main component. The double-ring ceramic capacitor is welded between a metal base and a metal cylindrical insert, then an insulating sleeve is inserted, a shell is installed, and finally, epoxy resin and anhydride curing agent, along with added silica powder and titanium dioxide, are used for resin encapsulation to produce a filter assembly.

[0006] On the one hand, the controller is usually quite large due to the need to accommodate these two components, which is not conducive to integrated controller design. On the other hand, the need to develop two sets of molds for the two components increases product development costs. In the original solution, the output copper busbar of the filter component was screwed to the input copper busbar of the DC-L I NK capacitor, which increased stray inductance and thus increased the power module's losses. Summary of the Invention

[0007] The technical problem to be solved by this utility model is to realize a more optimized integrated structure of motor controller EMC filter and DC capacitor.

[0008] To achieve the above objectives, the technical solution adopted by this utility model is as follows: an integrated structure of a motor controller EMC filter and a DC capacitor, wherein a positive busbar and a negative busbar clamp and fix the capacitor to form a strip-shaped capacitor assembly. One side of the capacitor assembly is provided with a DC output positive copper busbar and a DC output negative copper busbar, and the other side is provided with a DC input positive copper busbar and a DC input negative copper busbar. A magnetic ring is provided on the side of the capacitor assembly, and the DC input positive copper busbar and the DC input negative copper busbar pass through the magnetic ring. The capacitor assembly and the magnetic ring are fixed in an insulating injection molded support.

[0009] Six capacitors are connected between the positive busbar and the negative busbar. The six capacitors are connected in parallel and fixed to the positive busbar and the negative busbar by laser welding.

[0010] One end of the capacitor assembly is provided with a positive grounding Y capacitor, a positive grounding Y capacitor, a negative grounding Y capacitor, and a negative grounding Y capacitor fixed in an insulating injection molded support. The positive grounding Y capacitor and the positive grounding Y capacitor are connected between the positive busbar and the positive grounding copper busbar. The positive grounding Y capacitor and the positive grounding Y capacitor are in parallel. The negative grounding Y capacitor and the negative grounding copper busbar are connected between the negative grounding Y capacitor and the negative grounding copper busbar. The negative grounding Y capacitor and the negative grounding Y capacitor are in parallel. The positive grounding copper busbar and the negative grounding copper busbar extend out of the insulating injection molded support.

[0011] The insulating injection molded support includes a main area for placing capacitor components and a secondary area for placing magnetic rings. Both the main area and the secondary area are boxes with openings at the top. The secondary area is used to position the magnetic ring limiting structure. The secondary area is provided with a fixing cover. The fixing cover and the secondary area are fixed together by a snap-fit ​​connection. The DC output positive copper busbar and the DC output negative copper busbar are provided with multiple sets extending from the opening side of the main area.

[0012] The adhesive is poured into the main area, with the pouring depth slightly lower than the edge of the main area.

[0013] Both the DC output positive copper busbar and the DC input positive copper busbar are laser-welded to the positive busbar, and both the DC output negative copper busbar and the DC input negative copper busbar are laser-welded to the negative busbar. Both the outer ends of the DC input positive copper busbar and the DC input negative copper busbar are provided with press-fit nuts.

[0014] The magnetic ring has a parameter of 5uH, and its filtering effect range is concentrated in the range of 10MHz to 100MHz. The capacitor has a parameter of 45uF, and the total capacitance of multiple capacitors connected in parallel is 270uF.

[0015] The integrated structure of motor controller EMC filter and DC capacitor is applied in new energy vehicles.

[0016] This utility model's integrated structure, through the integrated design of magnetic ring, XY capacitor, and positive and negative copper busbars, can effectively suppress differential and common-mode components, meeting the increasingly stringent EMC requirements; at the same time, it maximizes the reduction of controller size and weight, lowers development costs, and meets the requirements of higher integration and higher reliability for electric drive systems. Attached Figure Description

[0017] The following is a brief explanation of the content and markings in each of the accompanying drawings in this utility model specification:

[0018] Figure 1 This is a schematic diagram of the welding assembly of the positive and negative copper busbars and the X and Y capacitors of this utility model;

[0019] Figure 2 This is a schematic diagram of the integrated EMC filter and DC capacitor structure of this utility model;

[0020] Figure 3 This is a schematic diagram of the limiting structure of the magnetic ring of this utility model;

[0021] Figure 4 This is a schematic diagram of the fixing structure of the fixing cover of this utility model;

[0022] Figure 5 This is a schematic diagram of the parallel arrangement of X capacitors according to this utility model;

[0023] Figure 6 This is a schematic diagram of the grounding copper busbar positioning structure of this utility model;

[0024] Figure 7 This is a schematic diagram of the glue-filling depth of this utility model.

[0025] Figure 8 This is a circuit diagram showing the arrangement of the magnetic ring and capacitor in this utility model.

[0026] The markings in the above diagrams are as follows: 1. Positive busbar; 2. Negative busbar; 3. DC output positive copper busbar; 4. DC output negative copper busbar; 5. Positive ground Y capacitor; 6. Positive ground Y capacitor; 7. Positive ground copper busbar; 8. Negative ground copper busbar; 9. Negative ground Y capacitor; 10. Negative ground Y capacitor; 11. Magnetic ring; 12. DC input positive copper busbar; 13. DC input negative copper busbar; 14. Steel sleeve; 15. Insulating injection molded support; 16. Fixing cover; 17. Press-fit nut; 18. Capacitor; 19. Epoxy resin. Detailed Implementation

[0027] The following description, with reference to the accompanying drawings, details the specific implementation of this utility model, including the shape and structure of each component, the relative positions and connections between the parts, the function and working principle of each part, the manufacturing process, and the operation and use methods. This will help those skilled in the art to have a more complete, accurate, and in-depth understanding of the inventive concept and technical solution of this utility model.

[0028] New energy vehicle motor controller EMC filter and DC capacitor integrated solution, such as Figure 1 As shown, it mainly includes positive busbar 1, negative busbar 2, DC output positive copper busbar 3, DC output negative copper busbar 4, positive grounding Y capacitor 5 (10nF), positive grounding Y capacitor 6 (100nF), positive grounding copper busbar 7, negative grounding copper busbar 8, negative grounding Y capacitor 9 (10nF), negative grounding Y capacitor 10 (100nF), magnetic ring 11, DC input positive copper busbar 12, DC input negative copper busbar 13, steel sleeve 14, insulating injection molded support 15, fixing cover 16, M8 press-fit nut 17, X capacitor 18 (45uF);

[0029] like Figure 1 As shown, positive busbar 1 and negative busbar 2 are arranged in an alternating vertical structure. The bottom of X capacitor 18 is laser-welded to negative busbar 2, and the top of X capacitor 18 is laser-welded to positive busbar 1. Three DC output positive copper busbars 3 are laser-welded to positive busbar 1, and three DC output negative copper busbars 4 are laser-welded to negative busbar 2. DC input positive copper busbar 12 and DC input negative copper busbar 13 are laser-welded to positive busbar 1 and negative busbar 2, respectively. Positive grounding Y capacitors 5 and 6 are welded between positive grounding copper busbar 7 and positive busbar 1, respectively, forming a parallel structure to suppress common-mode interference in the positive copper busbar. Negative grounding Y capacitors 9 and 10 are welded between negative grounding copper busbar 8 and negative busbar 2, respectively, forming a parallel structure to suppress common-mode interference in the negative copper busbar. A magnetic ring 11 (5uH, with a filtering effect concentrated in the 10MHz to 100MHz range) passes through the positive and negative copper busbars of the DC input to suppress high-frequency radiated interference within a specific frequency range in the circuit. Through the integrated design of the magnetic ring 11, XY capacitors, and positive and negative copper busbars, differential and common-mode components can be effectively suppressed, meeting increasingly stringent EMC requirements. Simultaneously, it maximizes the reduction of controller size and weight, lowers development costs, and meets the requirements of higher integration and reliability in electric drive systems.

[0030] As shown in Figure 2, first, the magnetic ring 1 is passed through the DC input positive and negative copper busbars, and then the positive and negative copper busbars are welded to the X and Y capacitors and the assembly is placed inside the insulating injection molded support 15. The insulating support has screw mounting positions for the entire module to be installed into the housing; the positive busbar 1 and the negative busbar 2 clamp the capacitors to form a capacitor assembly, and the capacitor assembly is a rectangular parallelepiped structure, with a positive grounding Y capacitor at one end; 5, positive grounding Y capacitor 6, positive grounding copper busbar 7, negative grounding copper busbar 8, negative grounding Y capacitor 9, and negative grounding Y capacitor 10, these components are all fixed in the main area of ​​the insulating injection molded support 15, the main area is a strip-shaped rectangular hollow structure with only one side open, and a secondary area is provided on one side of the insulating injection molded support 15, the secondary area is a smaller rectangular hollow structure used to place the magnetic ring 11, such as Figure 3 As shown, the magnetic ring 11 is placed inside the insulating injection molded support 15, and is limited in the left and right directions by the limiting structures a / b respectively. The upper position of the magnetic ring is fixed by the limiting surface c of the fixing cover 16. The fixing cover 16 and the insulating injection molded support 15 are connected by two left and right snap fasteners d.

[0031] like Figure 6 As shown, when placing the positive grounding copper busbar 7 and the negative grounding copper busbar 8, first insert the bent feet on the side of the copper busbars into the square holes of the insulating injection-molded brackets to fix their positions. Figure 5As shown, six X capacitors 18 are connected between the positive busbar 1 and the negative busbar 2. The six X capacitors 18 are connected in parallel (total capacitance 270uF) to suppress differential mode interference between the positive and negative copper busbars. The positive and negative terminals of the X capacitors 18 are laser welded to the positive and negative busbars, respectively.

[0032] like Figure 7 As shown, the main area is sealed by potting with epoxy resin 19, which needs to completely fill the main area. The edge of the potting resin (epoxy resin 19) is slightly lower than the edge of the main area shell, generally less than 1mm below the shell edge.

[0033] This utility model integrates the DC-L I NK capacitor and filter components into a single design. Compared to the original discrete design, the integrated design reduces the size of the components, thereby reducing the space required for the controller layout and making the controller more compact.

[0034] Compared to the original design and development of two parts, the integrated solution only requires the design of one part, which greatly reduces the cost of mold development and thus reduces the product development cost.

[0035] In the original design, the output copper busbar of the filter component and the input copper busbar of the DC-LINK capacitor were connected by screws, which increased the stray inductance of the circuit. Through integrated design, the filter component and the DC-LINK capacitor share a common busbar structure, avoiding screw connections, thereby reducing stray inductance, lowering power module losses, and improving controller efficiency.

[0036] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, are all within the protection scope of the present invention.

Claims

1. An integrated structure of an EMC filter and a DC capacitor for a motor controller, wherein a positive busbar and a negative busbar clamp and fix the capacitor to form a strip-shaped capacitor assembly. One side of the capacitor assembly is provided with a DC output positive copper busbar and a DC output negative copper busbar, and the other side is provided with a DC input positive copper busbar and a DC input negative copper busbar, characterized in that: A magnetic ring is provided on the side of the capacitor assembly. The DC input positive copper busbar and the DC input negative copper busbar pass through the magnetic ring. The capacitor assembly and the magnetic ring are fixed in an insulating injection molded support.

2. The integrated structure according to claim 1, characterized in that: Six capacitors are connected between the positive busbar and the negative busbar. The six capacitors are connected in parallel and fixed to the positive busbar and the negative busbar by laser welding.

3. The integrated structure according to claim 2, characterized in that: One end of the capacitor assembly is provided with a positive grounding Y capacitor, a positive grounding Y capacitor, a negative grounding Y capacitor, and a negative grounding Y capacitor fixed in an insulating injection molded support. The positive grounding Y capacitor and the positive grounding Y capacitor are connected between the positive busbar and the positive grounding copper busbar. The positive grounding Y capacitor and the positive grounding Y capacitor are in parallel. The negative grounding Y capacitor and the negative grounding copper busbar are connected between the negative grounding Y capacitor and the negative grounding copper busbar. The negative grounding Y capacitor and the negative grounding Y capacitor are in parallel. The positive grounding copper busbar and the negative grounding copper busbar extend out of the insulating injection molded support.

4. The integrated structure according to claim 1, 2 or 3, characterized in that: The insulating injection molded support includes a main area for placing capacitor components and a secondary area for placing magnetic rings. Both the main area and the secondary area are boxes with openings at the top. The secondary area is used to position the magnetic ring limiting structure. The secondary area is provided with a fixing cover. The fixing cover and the secondary area are fixed together by a snap-fit ​​connection. The DC output positive copper busbar and the DC output negative copper busbar are provided with multiple sets extending from the opening side of the main area.

5. The integrated structure according to claim 4, characterized in that: The adhesive is poured into the main area, with the pouring depth slightly lower than the edge of the main area.

6. The integrated structure according to claim 5, characterized in that: Both the DC output positive copper busbar and the DC input positive copper busbar are laser-welded to the positive busbar, and both the DC output negative copper busbar and the DC input negative copper busbar are laser-welded to the negative busbar. Both the outer ends of the DC input positive copper busbar and the DC input negative copper busbar are provided with press-fit nuts.

7. The integrated structure according to claim 6, characterized in that: The magnetic ring has a parameter of 5uH, and its filtering effect range is concentrated in the range of 10MHz to 100MHz. The capacitor has a parameter of 45uF, and the total capacitance of multiple capacitors connected in parallel is 270uF.

8. The integrated structure according to claim 1 or 7, characterized in that: The integrated structure of motor controller EMC filter and DC capacitor is applied in new energy vehicles.

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