Multistage filtering structure integrated with current acquisition

Abstract

The utility model discloses a multistage filtering structure integrated with current acquisition, which is used for filtering at a high-voltage end of a motor controller and comprises an injection molding shell, a nanocrystalline magnetic ring, a ferrite magnetic core and a filtering PCBA board, the injection molding shell is provided with a magnetic ring potting groove and a ferrite magnetic core potting groove, the injection molding shell is used for plastic coating of a positive / negative electrode copper bar, and the ferrite magnetic core potting groove is provided with a magnetic ring potting groove and a ferrite magnetic core potting groove. A magnetic gathering iron core is arranged on an output terminal of the positive pole copper bar and used for collecting current of a high-voltage input end, the filtering PCBA board is installed on the top of the injection molding shell in an inverted buckling mode, and a first filtering circuit located in front of the ferrite magnetic core and a second filtering circuit located behind the ferrite magnetic core are arranged on the filtering PCBA board. And the filter circuit I and the filter circuit II are respectively connected with the positive / negative copper bar to take electricity. According to the utility model, through the modular design, the product assembly process is simplified. A magnetism gathering iron core is designed at the high-voltage output end, a chip is inserted into a main control board to be used for collecting bus current, and monitoring of the current of the high-voltage input end is achieved.

Description

Technical Field

[0001] The utility model relates to a motor controller, in particular to a multi-stage filtering structure for integrated current collection. Background Art

[0002] Motor controllers often have interference, including interference in signal sampling, fluctuations in voltage and current, etc., so a filtering solution needs to be designed. Filtering is widely used in motor controllers to reduce noise, eliminate aliasing, and attenuate resonance, such as interference generated by electrical component interconnection, resolution limitations, EMI, and inherent noise in feedback devices.

[0003] When designing a filtering structure, the existing technical idea is generally to add filtering devices such as magnetic rings, magnetic cores, filter capacitors, and filter boards to the high-voltage input end according to EMC requirements, and arrange the corresponding filtering elements in a limited space to meet the system's electromagnetic compatibility requirements.

[0004] When designing the EMC of the high-voltage end of the controller, the traditional design method is to add a number of large and small filter capacitors, magnetic rings, filter circuit boards and other filter components in the current transmission path. However, the traditional EMC design method has the following two disadvantages:

[0005] 1. Since the filter components in the filter assembly are independent entities, a portion of space should be reserved for fixing the components during installation. When there are enough filter components, the space for accommodating the filter module at the DC end of the controller will be enlarged, the design space at the DC end will be compressed, and the design difficulty will be significantly increased;

[0006] 2. The filter elements are independent entities, the degree of integration of the filter modules is low, the installation process is cumbersome, the production cycle of the controller products will be lengthened, and the production efficiency will be significantly reduced. Utility Model Content

[0007] The utility model aims to provide a multi-stage filter structure with integrated current collection to improve the assembly processability of the filter structure.

[0008] To this end, the utility model provides a multi-stage filtering structure with integrated current collection, which is used for high-voltage end filtering of a motor controller, and includes an injection molded shell, a nanocrystalline magnetic ring, a ferrite core, and a filtering PCBA board. The injection molded shell has a magnetic ring potting groove and a ferrite core potting groove, wherein the nanocrystalline magnetic ring is potted in the magnetic ring potting groove, and the ferrite core is potted in the ferrite potting groove. The injection molded shell is used to encapsulate the positive / negative copper busbars, and a polymagnetic core is provided on the output terminal of the positive copper busbar for collecting current at the high-voltage input end. The injection molded shell is also used to encapsulate the polymagnetic core. The filtering PCBA board is invertedly installed on the top of the injection molded shell, and a filtering circuit 1 located before the ferrite core and a filtering circuit 2 located after the ferrite core are provided thereon. The filtering circuit 1 and the filtering circuit 2 are respectively connected to the positive / negative copper busbars for power collection.

[0009] Furthermore, the positive / negative copper busbar has a horizontal input terminal located inside the nanocrystalline magnetic ring, and the horizontal input terminal is used to be electrically connected to an external high-voltage terminal passing through the nanocrystalline magnetic ring.

[0010] Furthermore, the positive / negative copper busbar passes through the inner hole of the ferrite core in an upright posture, and the positive / negative copper busbar has a first pair of connection points located before the ferrite core and a second pair of connection points located after the ferrite core. The filtering PCBA board is connected to the first pair of connection points and the second pair of connection points by screws to obtain power.

[0011] Furthermore, the first pair of connection points include outward-turned lugs respectively arranged on the positive and negative copper busbars, and the outward-turned lugs are provided with rivet nuts.

[0012] Furthermore, the positive / negative copper busbars each include a copper busbar heat dissipation portion, wherein the bottom surface of the copper busbar heat dissipation portion is exposed for heat dissipation by conduction of the copper busbar.

[0013] Furthermore, the first filtering circuit comprises a plurality of capacitors, wherein the plurality of capacitors comprises an X capacitor connected between the positive and negative copper busbars for eliminating differential mode interference and a Y capacitor connected to the ground for eliminating common mode interference.

[0014] Furthermore, a plurality of capacitor protection grooves are formed on the injection-molded housing to protect the capacitor from being touched.

[0015] Furthermore, the injection molded housing is also used to overmold the steel sleeve to form an external mounting seat of the multi-stage filtering structure.

[0016] The utility model adopts modular design, in addition to splitting the nanocrystalline magnetic ring, the ferrite core, and the filter PCBA board into separate modules, the other components are integrally injection molded with the injection molded shell, and all the filter circuit components are integrated into the filter PCBA board, which simplifies the product assembly process.

[0017] At the same time, a magnetic core is designed at the high-voltage output end of multiple filter structures, and a chip is inserted on the main control board to collect the bus current, which realizes the monitoring of the current at the high-voltage input end, further improving the safety of the system and meeting the requirements of ASIL_D.

[0018] In addition to the above-described purposes, features and advantages, the present invention has other purposes, features and advantages. The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings constituting part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings:

[0020] Figure 1 It is a schematic diagram of the multi-stage filtering structure of the utility model;

[0021] Figure 2 yes Figure 1 Exploded diagram of

[0022] Figure 3 The figure shows the assembly position relationship between the exposed positive and negative copper bars and the filter components in the multi-stage filter structure;

[0023] Figure 4 The cross-sectional structure diagram of the magnetic core arranged on the positive copper busbar is shown;

[0024] Figure 5 is a schematic diagram of the filter PCBA board; and

[0025] Figure 6 It is an electrical principle diagram of the multi-stage filtering structure of the utility model. DETAILED DESCRIPTION

[0026] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0027] The utility model provides a multi-stage filtering structure for a high-voltage input end of a motor controller, and the filtering scheme can meet the requirements of EMC level 5 and ASIL_D.

[0028] Figure 1 It is a schematic diagram of the multi-stage filtering structure of the utility model. Figure 1 As shown, the multi-stage filtering structure includes a nanocrystalline magnetic ring 3, a ferrite core 4, a filtering PCBA board 5, and an injection molded housing 7.

[0029] Figure 2 It is an exploded diagram of the multi-stage filtering structure, such as Figure 2As shown, the multi-stage filter structure body is an injection molded shell 7, and the injection molded shell 7 is plastic-coated with positive and negative copper bars 1 / 2, a magnetic core 6, an embedded steel sleeve 8, and a riveted nut 9.

[0030] The magnetic core 6 is a U-shaped magnetic core, which has the function of magnetic concentration and is used to collect the current at the high voltage input end. The iron core 6 is integrally injection molded with the injection molded shell 7 and is arranged at the output end of the positive copper bus 1. Figure 4 The two ends of the magnetic core 6 extend upward from the control drive board 9 on the top, and the control drive board 9 is a circuit board on the motor controller. A current collection chip 10 is provided in the middle of the two ends of the magnetic core 6 to collect the current at the output end of the positive copper busbar through the magnetic core 6.

[0031] The nanocrystalline magnetic ring 3 is arranged outside the input end of the positive / negative copper bar 1 / 2 to absorb common mode interference, and is not limited to an oblong structure.

[0032] The ferrite core 4 is composed of an E core and an I core, and is disposed behind the nanocrystalline magnetic ring 3 to absorb common mode interference and differential mode interference.

[0033] The nanocrystalline magnetic ring 3 and the ferrite core 4 are fixed in the corresponding grooves 7a and 7b of the injection molded housing 7 through a potting process. The groove is also called a potting groove. The E core and the I core of the ferrite core 4 are fixed by gluing at the corresponding points in the potting groove and then potted.

[0034] Figure 3 The figure shows the assembly position relationship between the exposed positive and negative copper bars and the filter components in the multi-stage filter structure. Figure 3 As shown, the positive copper bar 1 includes a horizontal input terminal 11, a vertical extension 12, a horizontal output terminal 13, a pair of outward-turned lugs 14, and a copper bar heat dissipation portion 15. The structure of the negative copper bar 2 is similar to that of the positive copper bar, including a horizontal input terminal 21, a vertical extension 22, a horizontal output terminal 23, a pair of outward-turned lugs 24, and a copper bar heat dissipation portion 25.

[0035] The horizontal input terminal 11 is bent relative to the bottom of the vertical extension 12 and is equipped with a rivet nut 9. The horizontal output terminal 13 is bent relative to the top of the vertical extension 12 and is equipped with a rivet nut 9. Each outward-turned lug 14 is equipped with a rivet nut 9. A plurality of insert steel sleeves are arranged on the periphery of the injection-molded housing, and a plurality of connection seats are formed by integral injection molding.

[0036] In the positive and negative copper bars, except for the exposed top surfaces of the horizontal input terminal 11 for electrical connection, a pair of outward-turned lugs 14, and the horizontal output terminal 13, and the exposed bottom surface of the copper bar heat dissipation part 15, the other parts are all plastic-coated.

[0037] The upright extension portion 12 and the upright extension portion 22 are arranged side by side and the upright extension portion 12 is arranged outside, that is, the upright extension portion 12 is generally located on the same side of the multi-stage filtering structure as the nanocrystalline magnetic ring 3. The horizontal input terminal 11 and the horizontal input terminal 21 are arranged on the inner side of the nanocrystalline magnetic ring 3 and arranged side by side in the hole length direction of the nanocrystalline magnetic ring 3, and the horizontal input terminal 21 is located outside.

[0038] The copper bar heat dissipation part 15 is horizontally bent relative to the bottom of the vertical extension part, and is used for heat dissipation of the positive copper bar. Specifically, the copper bar heat dissipation part 15 has an exposed bottom surface, which contacts the thermal pad to achieve heat dissipation. The copper bar heat dissipation part 25 is the same, and is used for heat dissipation of the negative copper bar.

[0039] The pair of outward-turned lugs 14 of the positive and negative copper bars form a first pair of connection points located before the ferrite core and a second pair of connection points located after the ferrite core. Figure 4 and Figure 5 As shown in FIG. 1 , a filter circuit 1 connected to the first pair of connection points and a filter circuit 2 connected to the second pair of connection points are provided on the filter PCBA board.

[0040] The above-mentioned filter circuit 1 includes an X capacitor C9 / C10 connected between the positive and negative copper bars for eliminating differential mode interference, a first RC filter sub-circuit connected between the positive copper bar and the ground for eliminating common mode interference (the capacitors C1 / C2 are connected in parallel and connected in series with the chip resistor R1), and a second RC filter sub-circuit connected between the negative copper bar and the ground for eliminating common mode interference (the capacitors C3 / C4 are connected in parallel and connected in series with the chip resistor R4), wherein the first RC filter sub-circuit and the second RC filter sub-circuit are symmetrically arranged.

[0041] The above-mentioned second filter circuit includes an X capacitor C11 connected between the positive and negative copper bars for eliminating differential mode interference, a third RC filter sub-circuit connected between the positive copper bar and the ground for eliminating common mode interference (capacitor C5 is connected in series with the patch resistor R2, capacitor C6 is connected in series with the patch resistor R3, and the two are connected in parallel to the ground), and a fourth RC filter sub-circuit connected between the negative copper bar and the ground for eliminating common mode interference (capacitor C7 is connected in series with the patch resistor R5, capacitor C8 is connected in series with the patch resistor R6, and the two are connected in parallel to the ground), wherein the third RC filter sub-circuit and the fourth RC filter sub-circuit are symmetrically arranged.

[0042] The filter PCBA board 5 integrates 3 X capacitors and 8 Y capacitors. The X / Y capacitors are fixed on the PCB through pin welding, and a variety of arrangements can be realized, such as Figure 6As shown. The X capacitor is used to absorb differential mode interference, and the Y capacitor is used to absorb common mode interference. The injection molded housing is also formed with a plurality of capacitor protection grooves 7c with openings facing upward to protect the plurality of capacitors at the bottom of the filter PCBA board, especially the larger capacitors, from being touched by the outside world.

[0043] Four mounting holes are designed on the filter PCBA board 4, which are connected to the outward-turned lugs of the positive and negative copper bars 1 / 2 through four bolts to obtain power and are fixed on the injection molded housing 7.

[0044] The multi-stage filter structure of this embodiment is an LCLC filter structure, in which the nanocrystalline magnetic ring 3 constitutes the first stage, the filter circuit 1 on the filter PCBA board constitutes the second stage, the ferrite core constitutes the third stage, and the filter circuit 2 on the filter PCBA board constitutes the fourth stage. This filtering scheme can meet the requirements of EMC level 5 and ASIL_D.

[0045] The above description is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A multi-stage filtering structure with integrated current acquisition, used for DC high-voltage end filtering of a motor controller, characterized in that: The invention comprises an injection molded shell, a nanocrystalline magnetic ring, a ferrite core, and a filter PCBA board, wherein the injection molded shell has a magnetic ring potting groove and a ferrite core potting groove, wherein the nanocrystalline magnetic ring is potted in the magnetic ring potting groove, and the ferrite core is potted in the ferrite potting groove. The injection molded shell is used to encapsulate the positive / negative copper bars. The output terminal of the positive copper bar is provided with a magnetic core for collecting current at the high voltage input end. The injection molded shell is also used to encapsulate the magnetic core. The filter PCBA board is mounted upside down on the top of the injection molded shell, and is provided with a filter circuit 1 located before the ferrite core and a filter circuit 2 located after the ferrite core. The filter circuit 1 and the filter circuit 2 are respectively connected to the positive / negative copper busbars to obtain power.

2. The multi-stage filtering structure for integrated current acquisition according to claim 1 is characterized in that: The positive / negative copper busbar has a horizontal input terminal located inside the nanocrystalline magnetic ring, and the horizontal input terminal is used to be electrically connected to an external high-voltage terminal passing through the nanocrystalline magnetic ring.

3. The multi-stage filtering structure for integrated current acquisition according to claim 1 is characterized in that: The positive / negative copper busbar passes through the inner hole of the ferrite core in an upright posture. The positive / negative copper busbar has a first pair of connection points located before the ferrite core and a second pair of connection points located after the ferrite core. The filter PCBA board is connected to the first pair of connection points and the second pair of connection points by screws to obtain power.

4. The multi-stage filtering structure for integrated current acquisition according to claim 3 is characterized in that: The first pair of connection points include outward-turned lugs respectively arranged on the positive and negative copper bars, and the outward-turned lugs are provided with rivet nuts.

5. The multi-stage filtering structure for integrated current acquisition according to claim 3 is characterized in that: The positive / negative copper busbars each further include a copper busbar heat dissipation portion, wherein the bottom surface of the copper busbar heat dissipation portion is exposed for heat dissipation by conduction of the copper busbar.

6. The multi-stage filtering structure for integrated current acquisition according to claim 3 is characterized in that: The first filter circuit includes a plurality of capacitors, including an X capacitor connected between the positive / negative copper busbars for eliminating differential mode interference and a Y capacitor connected to the ground for eliminating common mode interference.

7. The multi-stage filtering structure for integrated current acquisition according to claim 6, characterized in that: The injection molded housing is also formed with a plurality of capacitor protection grooves with openings facing upwards to protect the capacitors from being touched.

8. The multi-stage filtering structure for integrated current acquisition according to claim 1, characterized in that: The injection molded housing is also used to overmold the insert steel sleeve to form an external mounting seat of the multi-stage filtering structure.

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