Filter structure, drive device and electric drive system

Abstract

Disclosed in the present application are a filter structure, a drive device and an electric drive system. The filter structure comprises a first magnetic core and a second magnetic core, wherein the first magnetic core comprises a first through hole, a second through hole and a third through hole, the first through hole being configured for a first conductive bus bar to pass through, the second through hole being configured for a second conductive bus bar to pass through, and the third through hole being configured for a third conductive bus bar to pass through. The second magnetic core is provided between the first through hole and the second through hole, and by means of setting a saturation magnetic flux density of the second magnetic core to be lower than that of the first magnetic core, when the current on the conductive bus bars is gradually increased, the second magnetic core enters a saturated state in advance, which not only reduces the magnetic permeability, but also prevents the first magnetic core from becoming saturated as the current continues to rise, thus maintaining a filtering function of the first magnetic core; consequently, the coupling coefficients of the first conductive bus bar, the second conductive bus bar and the third conductive bus bar are reduced after power-on, thereby ensuring that the EMC of electric drive positive and negative electrodes remains unchanged.

Description

A filter structure, a driving device, and a motor driving system

[0001] This application refers to Chinese Patent Application No. 202410264011.4 filed on March 7, 2024, entitled “Filter Structure, Drive Device, Motor Drive System,” which is incorporated herein by reference in its entirety. Technical Field

[0002] The present application relates to the field of filter technology, and in particular to a filter structure, a drive device, and a motor drive system. Background Art

[0003] With the widespread adoption of electric drive systems (EDS), the voltage level of these systems has gradually increased to 800V. To meet the current market requirement of 400V DC chargers capable of charging 800V battery packs, the current mainstream approach involves adding a relay between the charger and the motor. This circuit utilizes the motor windings as a boost inductor, which, together with the inverter's switching module, forms a boost circuit, thereby integrating the boost function into the motor drive system. At the same time, the electromagnetic compatibility (EMC) of electric vehicles is gaining increasing attention. Faced with harsh and complex electromagnetic environments, the requirements for electromagnetic interference (EMI) and electromagnetic susceptibility (EMS) of electric vehicle components are becoming increasingly stringent.

[0004] When the relay is disconnected, the motor drive system is in a normal driving mode. When the relay is closed, the motor drive system is in a Boost charging mode. However, when the current motor drive system operates in a mode that includes a Boost function, there is a problem of degraded EMC performance of the motor drive system. Technical issues

[0005] In view of the above problems, the present application provides a filter structure, a drive device, and a motor drive system, aiming to provide a filter structure that can solve the problem of degraded EMC performance of the motor drive system when the motor drive system operates in a mode including a Boost function. Technical Solutions

[0006] A first aspect of an embodiment of the present application provides a filter structure, the filter structure comprising: a first magnetic core, a second magnetic core;

[0007] The first magnetic core includes a first through hole, a second through hole, and a third through hole, wherein the first through hole is used to pass the first conductive cable, the second through hole is used to pass the second conductive cable, and the third through hole is used to pass the third conductive cable;

[0008] The second magnetic core is disposed between the first through hole and the second through hole, and a saturation magnetic flux density of the second magnetic core is smaller than a saturation magnetic flux density of the first magnetic core.

[0009] In the technical solution of the embodiment of the present application, the first through hole is used to pass through the first conductive cable, the second through hole is used to pass through the second conductive cable, and the third through hole is used to pass through the third conductive cable. By providing a second magnetic core between the first through hole and the second through hole, and setting the saturation magnetic flux density of the second magnetic core to be smaller than the saturation magnetic flux density of the first magnetic core, the second magnetic core can enter the saturation state in advance when the current on the conductive cable gradually increases, which not only reduces the magnetic permeability, but also prevents the first magnetic core from entering the saturation state as the current continues to increase, thereby maintaining the filtering function of the first magnetic core, thereby reducing the coupling coefficient between the first conductive cable, the second conductive cable and the third conductive cable, and ensuring that the EMC performance of the positive and negative poles of the motor drive remains unchanged.

[0010] In some embodiments, the second through hole and the third through hole are connected via a magnetic core air gap.

[0011] In the technical solution of the embodiment of the present application, the second through-hole is connected to the third through-hole by a magnetic core air gap. The size of the magnetic core air gap is determined according to the operating conditions of the motor drive. In the motor drive mode, the direction of the current in the second conductive cable is opposite to the direction of the current in the third conductive cable, and the magnetic field generated can be offset within the first magnetic core. Therefore, the first magnetic core will not saturate and can operate normally in the motor drive mode. A second magnetic core is provided between the first and second conductive cables. In the boost charging mode, the current flowing through the first conductive cable is opposite to the current flowing through the second and third conductive cables, and the magnetic field generated by them can be offset within the first magnetic core. Therefore, the first magnetic core will not saturate and can operate normally. This design ensures that the first magnetic core will not saturate in different operating modes, and the coupling coefficient between the first conductive cable and the second and third conductive cables is reduced, ensuring stable EMC performance on the positive and negative DC sides.

[0012] In some embodiments, an angle between an axis of symmetry of a cross section of the second through hole and an axis of symmetry of a cross section of the third through hole is any angle between 0° and 180°.

[0013] In some embodiments, an axis of symmetry of a cross section of the second through hole and an axis of symmetry of a cross section of the third through hole are parallel to each other; and / or

[0014] An axis of symmetry of a cross section of the second through hole is parallel to an axis of symmetry of a cross section of the first through hole.

[0015] In some embodiments, the symmetry axis of the cross section of the second through hole and the symmetry axis of the cross section of the third through hole are perpendicular to each other; and / or

[0016] An axis of symmetry of a cross section of the second through hole is perpendicular to an axis of symmetry of a cross section of the first through hole.

[0017] In some embodiments, the symmetry axis of the cross section of the first through hole, the symmetry axis of the cross section of the second through hole, and the symmetry axis of the cross section of the third through hole may be the longest symmetry axis of their cross sections.

[0018] In some embodiments, the height of the second magnetic core is greater than the height of the first through hole or greater than the height of the second through hole.

[0019] In the technical solution of the embodiments of the present application, by setting the height of the second magnetic core to be greater than the height of the first through-hole or greater than the height of the second through-hole, the second magnetic core can completely cover the area between the first and second through-holes. Furthermore, by utilizing the second magnetic core's relatively low saturation flux, the second magnetic core enters saturation first when current flows through the conductive cable, maintaining a low magnetic permeability. At this point, the second magnetic core is close to an insulating gas air gap, and the first magnetic core does not enter saturation as the current in the conductive cable continues to increase. This allows the first magnetic core to perform its filtering function, reducing the coupling coefficient between the first, second, and third conductive bars, preventing noise generated by the parasitic capacitance of the first conductive cable from coupling to the second and third conductive cables through the first magnetic core, and improving the EMC stability of the motor drive system.

[0020] In some embodiments, a third magnetic core is disposed between the second through hole and the third through hole.

[0021] In the technical solution of the embodiment of the present application, a third magnetic core can be provided between the second through hole and the third through hole. Another magnetic flux path can be added through the third magnetic core, thereby reducing the coupling coefficient between the second conductive cable and the third conductive cable. This can prevent the noise generated by the parasitic capacitance generated by the first conductive cable from being coupled to the second and third conductive cables through the first magnetic core, thereby improving the EMC stability of the motor drive system.

[0022] In some embodiments, at least one of the first side of the third magnetic core and the second side of the third magnetic core is provided with a first air gap; and a line between the first side of the third magnetic core and the second side of the third magnetic core intersects a line between the second through hole and the third through hole.

[0023] In the technical solution of the embodiment of the present application, a first air gap is provided on at least one of the first side of the third magnetic core and the second side of the third magnetic core, and the second through hole and the third through hole are connected by the third magnetic core and the first air gap, so that multiple magnetic flux paths can be provided between the second conductive cable and the third conductive cable. By adding multiple magnetic cores or distributing the air gaps, the edge effect of a single air gap on the second conductive cable and the third conductive cable can be reduced, thereby reducing the edge loss of the second conductive cable and the third conductive cable.

[0024] In some embodiments, at least one second air gap is provided in the third magnetic core, and the second air gap connects the second through hole and the third through hole.

[0025] In the technical solution of the embodiment of the present application, a second air gap is provided on at least one of the first side of the third magnetic core and the second side of the third magnetic core, and the second through hole and the third through hole are connected by the third magnetic core and the second air gap, so that multiple magnetic flux paths can be provided between the second conductive cable and the third conductive cable. Therefore, by adding multiple magnetic cores or distributing the air gaps, the edge effect of a single air gap on the second conductive cable and the third conductive cable is reduced, thereby reducing the edge loss of the second conductive cable and the third conductive cable.

[0026] In some embodiments, when there are multiple second air gaps, the second air gaps are evenly distributed.

[0027] In some embodiments, the first magnetic core is polygonal or elliptical.

[0028] In the technical solution of the embodiment of the present application, the shape of the first magnetic core can be set according to the application scenario of the motor drive system. By setting the first magnetic core to a regular shape, it is conducive to generating a uniformly distributed magnetic field in the first magnetic core, so that the noise coupled by the first magnetic core to the second conductive cable and the third conductive cable is smaller, thereby improving the EMC stability of the motor drive system.

[0029] In some embodiments, an insulating medium is filled between the first through hole and the first magnetic core; and / or

[0030] An insulating medium is filled between the second through hole and the first magnetic core; and / or

[0031] An insulating medium is filled between the third through hole and the first magnetic core.

[0032] In some embodiments, the insulating medium is an insulating gas or an insulating component; wherein the insulating component may be an insulating injection molded part.

[0033] In some embodiments, the first magnetic core is made of nanocrystalline material or high magnetic flux density ferrite material.

[0034] In some embodiments, the second magnetic core is a low flux density ferrite material.

[0035] A second aspect of an embodiment of the present application further provides a filter circuit, including a first conductive wire, a second conductive wire, a third conductive wire, and a filter structure as described in any one of the above items, wherein the first conductive wire passes through the first through hole, the second conductive wire passes through the second through hole, and the third conductive wire passes through the third through hole.

[0036] In some embodiments, the filtering circuit further comprises:

[0037] At least one first capacitor is connected between the second conductive wire and ground.

[0038] In some embodiments, the filtering circuit further comprises:

[0039] At least one second capacitor is connected between the third conductive line and ground.

[0040] A third aspect of the embodiments of the present application further provides a driving device for connecting to a battery pack, a charging device, and a motor, wherein the driving device includes a filter structure as described in any one of the above embodiments.

[0041] A fourth aspect of the embodiments of the present application further provides a driving device for connecting to a battery pack, a charging device, and a motor, wherein the driving device includes a filter circuit as described in any one of the above embodiments.

[0042] In some embodiments, the driving device further includes: a DC bus capacitor, a power module, and a first switch;

[0043] The battery pack, the DC bus capacitor, and the power module are connected in parallel between the second conductive cable and the third conductive cable. The first end of the charging device is connected to the second conductive cable, the second end of the charging device is connected to the first conductive cable via the first switch, and the first conductive cable is connected to the power module via the motor.

[0044] The power module is used to drive the motor to work when the first switch is disconnected;

[0045] The charging device is used to charge the battery pack via the first conductive cable, the coil of the motor, and the power module when the first switch is turned on.

[0046] In some embodiments, the driving device further includes: a filter capacitor, wherein the filter capacitor is connected in parallel to both ends of the charging device.

[0047] A fifth aspect of an embodiment of the present application further provides a motor drive system, comprising: a battery pack, a charging device, a motor; and a filter structure as described in any one of the above.

[0048] A sixth aspect of an embodiment of the present application further provides a motor drive system, comprising: a battery pack, a charging device, a motor; and a filter circuit as described in any one of the above.

[0049] A seventh aspect of an embodiment of the present application further provides a motor drive system, comprising: a battery pack, a charging device, a motor; and a drive device as described in any one of the above.

[0050] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. Beneficial effects

[0051] In the technical solution of the embodiment of the present application, a first magnetic core and a second magnetic core, the first magnetic core includes a first through hole, a second through hole, and a third through hole, wherein the first through hole is used to pass the first conductive cable, the second through hole is used to pass the second conductive cable, and the third through hole is used to pass the third conductive cable. A second magnetic core is provided between the first through hole and the second through hole. By setting the saturation magnetic flux density of the second magnetic core to be smaller than the saturation magnetic flux density of the first magnetic core, the second magnetic core can enter the saturation state in advance when the current on the conductive cable gradually increases, which not only reduces the magnetic permeability, but also prevents the first magnetic core from entering the saturation state as the current continues to increase, thereby maintaining the filtering function of the first magnetic core, thereby reducing the coupling coefficient between the first conductive cable, the second conductive cable and the third conductive cable, and ensuring that the EMC performance of the positive and negative poles of the motor drive remains unchanged. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present application. The same reference numerals are used throughout the drawings to represent the same components. In the drawings:

[0053] FIG1 is a schematic diagram of a first structure of a filter structure provided in an embodiment of the present application;

[0054] FIG2 is a schematic diagram of a second structure of a filter structure provided in an embodiment of the present application;

[0055] FIG3 is a schematic diagram of a third structure of a filter structure provided in an embodiment of the present application;

[0056] FIG4 is a schematic diagram of a fourth structure of a filter structure provided in an embodiment of the present application;

[0057] FIG5 is a schematic diagram of a fifth structure of a filter structure provided in an embodiment of the present application;

[0058] FIG6 is a schematic diagram of a sixth structural embodiment of the filter structure provided in the present application;

[0059] FIG7 is a schematic diagram of a seventh structure of a filter structure provided in an embodiment of the present application;

[0060] FIG8 is a schematic diagram of an eighth structural embodiment of the filter structure provided in the present application;

[0061] FIG9 is a ninth structural diagram of a filter structure provided in an embodiment of the present application;

[0062] FIG10 is a schematic diagram of the structure of a filter circuit provided in an embodiment of the present application;

[0063] FIG11 is a schematic structural diagram of a driving device provided in an embodiment of the present application. Modes for Carrying Out the Invention

[0064] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0065] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned figure descriptions are intended to cover non-exclusive inclusions.

[0066] In the description of the embodiments of this application, the technical terms "first" and "second" are used only to distinguish different objects and should not be understood to indicate or imply relative importance or implicitly specify the quantity, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0067] References to "embodiments" herein mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present application. References to the phrase "second connection port" at various locations in the specification do not necessarily refer to the same embodiment, nor do they constitute independent or alternative embodiments that are mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0068] In the description of the embodiments of this application, the term "and / or" is simply a description of the association relationship between associated objects, indicating that three relationships can exist. For example, A and / or B can represent the following three situations: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0069] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", 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 embodiments 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 embodiments of the present application.

[0070] To meet the requirement that a 400V DC charging station can charge an 800V battery pack, a relay is added between the charging station and the motor. The motor winding is used as a boost inductor and forms a Boost DC boost circuit with the inverter's switching module, thereby integrating the Boost DC boost function into the motor drive system. When the relay is disconnected, the motor drive system is in normal drive mode. When the relay is closed, the motor drive system is in Boost charging mode. However, current motor drive systems operating in a mode that includes the Boost function may experience a degradation in the EMC performance of the motor drive system.

[0071] To address the above technical issues, an embodiment of the present application provides a filter structure. Referring to FIG1 , the filter structure includes: a first magnetic core 110, a first through-hole 210, a second through-hole 220, and a third through-hole 230. The first through-hole 210, the second through-hole 220, and the third through-hole 230 are disposed within the first magnetic core 110, with a second magnetic core 120 disposed between the first through-hole 210 and the second through-hole 220. The saturation magnetic flux density of the second magnetic core 120 is lower than that of the first magnetic core 110. The first through-hole 210 is configured to pass through a first conductive cable, the second through-hole 220 is configured to pass through a second conductive cable, and the third through-hole 230 is configured to pass through a third conductive cable.

[0072] In this embodiment, by disposing the second magnetic core 120 between the first through hole 210 and the second through hole 220, and setting the saturation magnetic flux density of the second magnetic core 120 to be less than the saturation magnetic flux density of the first magnetic core 110, the second magnetic core 120 can enter the saturation state in advance when the current on the conductive cable gradually increases. This not only reduces the magnetic permeability, but also prevents the first magnetic core 110 from entering the saturation state as the current continues to increase, thereby maintaining the filtering function of the first magnetic core 110. Therefore, when the first conductive cable, the second conductive cable, and the third conductive cable are powered on, the coupling coefficient between the first conductive cable, the second conductive cable, and the third conductive cable is reduced, thereby ensuring that the EMC performance of the positive and negative poles of the motor drive remains unchanged.

[0073] In some embodiments, the third conductive cable and the second conductive cable respectively pass through the third through-hole and the second through-hole and then connect to the positive and negative electrodes of the battery pack. The positive electrode of the battery pack is connected to the first end of the power module via the third conductive cable, and the negative electrode of the battery pack is connected to the second end of the power module via the second conductive cable. The power module is connected to the first conductive cable via the motor. The power module can be composed of multiple bridge arms, the number of bridge arms corresponding to the phase of the motor. The first conductive cable, the coil in the motor, and the bridge arms in the power module constitute a Boost DC boost circuit. For example, in Boost charging mode, the charging device uses the Boost DC boost circuit to boost the 400V voltage to 800V DC voltage to charge the battery pack.

[0074] In some embodiments, the second through hole 220 and the third through hole 230 are connected via a magnetic core air gap.

[0075] In this embodiment, the core air gap can be a small through-hole between the second through-hole 220 and the third through-hole 230. The second through-hole 220 and the third through-hole 230 are connected by the core air gap, and the diameter of the core air gap is determined according to the motor drive operating conditions. When the first conductive cable passes through the first through-hole 210, the second conductive cable passes through the second through-hole 220, and the third conductive cable passes through the third through-hole 230, in motor drive mode, the current flowing through the second conductive cable is opposite to the current flowing through the third conductive cable, and the resulting magnetic field can be offset within the first magnetic core 110. Therefore, the first magnetic core 110 will not saturate and can operate normally in motor drive mode. A second magnetic core 120 is provided between the first through-hole 210 and the second through-hole 220. In boost charging mode, the current flowing through the first conductive cable is opposite to the current flowing through the second and third conductive cables, and the resulting magnetic field can be offset within the first magnetic core 110, preventing saturation and allowing the first magnetic core 110 to operate normally. This design ensures that the first magnetic core 110 will not be saturated in different working modes, and the coupling coefficient between the first conductive wire and the second conductive wire and the third conductive wire is reduced, thereby ensuring the stability of the EMC performance of the DC positive and negative sides.

[0076] In some embodiments, the cross-section of the first through hole 210 is axially symmetrical.

[0077] In some embodiments, the cross-section of the second through hole 220 is axially symmetrical.

[0078] In some embodiments, the cross-section of the third through hole 230 is axially symmetrical.

[0079] In some embodiments, the angle between the axis of symmetry of the cross section of the second through hole 220 and the axis of symmetry of the cross section of the third through hole 230 is any angle between 0° and 180°.

[0080] In this embodiment, the cross-sectional shape of the first conductive wire matches the cross-sectional shape of the first through hole 210, the cross-sectional shape of the second conductive wire matches the cross-sectional shape of the second through hole 220, and the cross-sectional shape of the third conductive wire matches the cross-sectional shape of the third through hole 230. When the first conductive wire passes through the first through hole 210, the second conductive wire passes through the second through hole 220, and the third conductive wire passes through the third through hole 230, the angle between the axes of symmetry of the cross-sectional shapes of the second conductive wire and the third conductive wire is related to the coupling coefficient between the second conductive wire and the third conductive wire. The coupling coefficient between the second conductive wire and the third conductive wire can be reduced by adjusting the angle between the cross-sectional shapes of the second conductive wire and the third conductive wire according to the requirements of the application scenario.

[0081] In some embodiments, the angle between the symmetry axis of the cross section of the second through hole 220 and the symmetry axis of the cross section of the third through hole 230 may be the angle between the long side of the cross section of the second through hole 220 and the long side of the cross section of the third through hole 230 .

[0082] In some embodiments, the angle between the axis of symmetry of the cross section of the second through hole 220 and the axis of symmetry of the cross section of the first through hole 210 is any angle between 0° and 180°.

[0083] In this embodiment, the cross-sectional shape of the first conductive wire matches the cross-sectional shape of the first through hole 210, the cross-sectional shape of the second conductive wire matches the cross-sectional shape of the second through hole 220, and the cross-sectional shape of the third conductive wire matches the cross-sectional shape of the third through hole 230. When the first conductive wire passes through the first through hole 210, the second conductive wire passes through the second through hole 220, and the third conductive wire passes through the third through hole 230, the angle between the cross-sections of the second conductive wire and the first conductive wire is related to the coupling coefficient between the second conductive wire and the first conductive wire. The coupling coefficient between the first conductive wire and the second conductive wire can be reduced by adjusting the angle between the cross-sections of the first conductive wire and the second conductive wire according to the requirements of the application scenario.

[0084] In some embodiments, the angle between the cross section of the second through hole 220 and the cross section of the first through hole 210 may be the angle between the long side of the cross section of the second through hole 220 and the long side of the cross section of the first through hole 210 .

[0085] In some embodiments, as shown in FIG. 2 , the second through hole 220 and the third through hole 230 are disposed in parallel.

[0086] In some embodiments, as shown in FIG. 2 , the second through hole 220 is disposed parallel to the first through hole 210 .

[0087] In some embodiments, as shown in FIG. 3 , the second through hole 220 and the third through hole 230 are disposed perpendicularly.

[0088] In some embodiments, referring to FIG. 3 and FIG. 6 , the second through hole 220 is disposed perpendicular to the first through hole 210 .

[0089] In some embodiments, as shown in FIG. 3 , the height of the second magnetic core 120 is greater than the height of the first through hole 210 .

[0090] In some embodiments, as shown in FIG. 4 , the height of the second magnetic core 120 is greater than the height of the second through hole 220 .

[0091] In this embodiment, by setting the height of the second magnetic core 120 to be greater than the height of the first through-hole 210 or greater than the height of the second through-hole 220, the second magnetic core 120 can completely cover the area between the first through-hole 210 and the second conductive cable 220. Furthermore, the relatively low saturation magnetic flux of the second magnetic core 120 allows the second magnetic core 120 to enter a saturation state first when current flows through the conductive cable, maintaining a low magnetic permeability. In this case, the magnetic permeability of the second magnetic core 120 is close to that of an insulating gas (e.g., air). The first magnetic core 110 does not enter a saturation state as the current in the first conductive cable continues to increase. This allows the first magnetic core 110 to perform its filtering function, preventing noise generated by the parasitic capacitance of the first conductive cable from coupling to the second and third conductive cables through the first magnetic core 110, thereby improving the EMC stability of the motor drive system.

[0092] In some embodiments, as shown in FIG. 7 , a third magnetic core 320 is disposed between the second through hole 220 and the third through hole 230 .

[0093] In this embodiment, a third magnetic core 320 can be provided between the second through hole 220 and the third through hole 230. The third magnetic core 320 can add another magnetic flux path, thereby reducing the coupling coefficient between the second conductive cable and the third conductive cable. This can prevent the noise generated by the parasitic capacitance generated by the first conductive cable from being coupled to the second and third conductive cables through the first magnetic core 110, thereby improving the EMC stability of the motor drive system.

[0094] In some embodiments, as shown in Figure 7, at least one of the first side of the third magnetic core 320 and the second side of the third magnetic core 320 is provided with a first air gap 330; the line between the first side of the third magnetic core 320 and the second side of the third magnetic core 320 intersects the line between the second through hole 220 and the third through hole 230.

[0095] In this embodiment, a first air gap 330 is provided on at least one of the first side of the third magnetic core 320 and the second side of the third magnetic core 320. The second through hole 220 and the third through hole 230 are connected by the third magnetic core 320 and the first air gap 330, so that there can be multiple magnetic flux paths between the second through hole 220 and the third through hole 230. By adding multiple magnetic cores or distributing the air gaps, the edge effect of a single air gap on the second conductive wire and the third conductive wire is reduced, thereby reducing the edge loss of the second conductive wire and the third conductive wire.

[0096] As shown in FIG. 7 , first air gaps 330 are provided on both the upper and lower sides of the third magnetic core 320 .

[0097] In some embodiments, as shown in FIG. 8 , at least one second air gap 350 is defined in the third magnetic core 320 , and the second air gap 350 connects the second through hole 220 and the third through hole 230 .

[0098] In this embodiment, a second air gap 350 is provided on at least one of the first side of the third magnetic core 320 and the second side of the third magnetic core 320. The second through hole 220 and the third through hole 230 are connected by the third magnetic core 320 and the second air gap 350, so that there can be multiple magnetic flux paths between the second through hole 220 and the third through hole 230. By adding multiple magnetic cores or distributing the air gaps, the edge effect of a single air gap on the second conductive wire and the third conductive wire is reduced, thereby reducing the edge loss of the second conductive wire and the third conductive wire.

[0099] In some embodiments, as shown in FIG. 8 , when there are multiple second air gaps 350 , the second air gaps 350 are evenly distributed.

[0100] In this embodiment, by providing the second air gap 350 to form a distributed air gap, the eddy current loss of the first magnetic core 110 can be reduced, the edge effect of a single air gap on the second and third conductive lines can be reduced, and the edge loss of the second and third conductive lines can be reduced.

[0101] In some embodiments, the saturation magnetic flux density of the third magnetic core 320 may be the same as the saturation magnetic flux density of the first magnetic core 110 , and may also be the same as the saturation magnetic flux density of the second magnetic core 120 .

[0102] In some embodiments, the saturation magnetic flux density of the third magnetic core 320 may be greater than the saturation magnetic flux density of the second magnetic core 120 , and may also be less than the saturation magnetic flux density of the first magnetic core 110 .

[0103] In some embodiments, the first magnetic core 110 is polygonal or elliptical.

[0104] In this embodiment, the shape of the first magnetic core 110 can be set according to the application scenario of the motor drive system. By setting the first magnetic core 110 to a regular shape, it is beneficial to generate a uniformly distributed magnetic field in the first magnetic core 110, so that the noise coupled to the second conductive cable and the third conductive cable by the first magnetic core 110 is smaller, thereby improving the EMC stability of the motor drive system.

[0105] In one embodiment, the first magnetic core 110 has a symmetrical structure.

[0106] In one embodiment, as shown in FIG. 8 , the first magnetic core 110 is octagonal.

[0107] In one embodiment, as shown in FIG. 5 , the first magnetic core 110 is rectangular.

[0108] In one embodiment, as shown in FIG. 3 , the first magnetic core 110 is elliptical.

[0109] In some embodiments, an insulating medium is filled between the first through hole 210 and the first magnetic core 110 .

[0110] In this embodiment, as shown in FIG. 1 , the first through hole 210 and the first magnetic core 110 are isolated by a first insulating dielectric layer 410 . The first insulating dielectric layer 410 is formed around the first through hole 210 .

[0111] In some embodiments, an insulating medium is filled between the second through hole 220 and the first magnetic core 110 .

[0112] In this embodiment, as shown in Figure 9, the second through hole 220 and the first magnetic core 110 are isolated by the second insulating dielectric layer 420, the second insulating dielectric layer 420 wraps the second through hole 220, and the second magnetic core 120 is in contact with the first insulating dielectric layer 410 and the second insulating dielectric layer 420 respectively.

[0113] In some embodiments, an insulating medium is filled between the third through hole 230 and the first magnetic core 110 .

[0114] In this embodiment, as shown in Figure 1, the third through hole 230 is isolated from the first magnetic core 110 by the third insulating dielectric layer 430, the third insulating dielectric layer 430 wraps the third through hole 230, and the magnetic core air gap is in contact with the second insulating dielectric layer 420 and the third insulating dielectric layer 430 respectively.

[0115] In some embodiments, the insulating medium is an insulating gas or an insulating component, wherein the insulating component may be an insulating component.

[0116] In some embodiments, the insulating gas may be air, a rare gas, or nitrogen.

[0117] In some embodiments, the first magnetic core 110 is made of nanocrystalline material or high magnetic flux density ferrite material.

[0118] In some embodiments, the second magnetic core 120 is made of a low magnetic flux density ferrite material.

[0119] An embodiment of the present application further provides a filter circuit, as shown in Figure 9, the filter circuit includes a first conductive wire 211, a second conductive wire 221, a third conductive wire 231, and a filter structure as described in any of the above embodiments, wherein the first conductive wire 211 passes through the first through hole 210, the second conductive wire 221 passes through the second through hole 220, and the third conductive wire 231 passes through the third through hole 230.

[0120] In some embodiments, the power module may be an inverter.

[0121] In some embodiments, the first conductive busbar 211 , the second conductive busbar 221 , and the third conductive busbar 231 are all copper busbars.

[0122] In some embodiments, the distance between the first conductive trace 211 and the inner wall of the first through hole 210 is the same.

[0123] In some embodiments, the distances between the second conductive trace 221 and the inner wall of the second through hole 220 are the same.

[0124] In some embodiments, the distances between the third conductive wire 231 and the inner wall of the third through hole 230 are the same.

[0125] In some embodiments, the cross-sectional shapes of the first conductive trace 211 and the first through hole 210 are the same.

[0126] In some embodiments, the second conductive trace 221 and the second through hole 220 have the same cross-sectional shape.

[0127] In some embodiments, the third conductive wire 231 and the third through hole 230 have the same cross-sectional shape.

[0128] In some embodiments, as shown in FIG. 10 , the filter circuit further includes at least one first capacitor 502 . The first capacitor 502 is connected between the second conductive trace 221 and the ground.

[0129] In this embodiment, the first conductive cable 211 passes through the first through-hole 210, the second conductive cable 221 passes through the second through-hole 220, and the third conductive cable 231 passes through the third through-hole 230. When the motor drive system is in the motor drive mode, the first conductive cable 211 contains transient switching voltage and high voltage. In addition, when the first through-hole 210 is arranged, a certain parasitic capacitance 501 exists after the first conductive cable 211 passes through the first through-hole 210, thereby generating a noise interference source. The noise interference source is then coupled to the second conductive cable 221 and the third conductive cable 231 through the third through-hole 230 via the first magnetic core 110. In this embodiment, by providing a first capacitor 502 connected between the second conductive cable 221 and the ground, and disposing a second magnetic core 120 having a magnetic flux density less than the saturation magnetic flux density of the first magnetic core 110 between the first through-hole 210 and the second through-hole 220, the second magnetic core 120 can enter a saturation state in advance when the current on the first conductive cable 211 gradually increases. This not only reduces the magnetic permeability, but also prevents the first magnetic core 110 from entering a saturation state as the current continues to increase, thereby maintaining the filtering function of the first magnetic core 110. This reduces the coupling coefficient between the first conductive cable 211, the second conductive cable 221, and the third conductive cable 231, thereby ensuring that the EMC performance of the positive and negative poles of the motor drive remains unchanged.

[0130] In some embodiments, as shown in FIG. 10 , the filter circuit further includes: at least one second capacitor 503 , and the second capacitor 503 is connected between the third conductive wire 231 and the ground.

[0131] In this embodiment, by providing a second capacitor 503 connected between the third conductive cable 231 and ground, and disposing a second magnetic core 120 having a magnetic flux density less than the saturation magnetic flux density of the first magnetic core 110 between the first through-hole 210 and the second through-hole 220, the second magnetic core 120 can enter a saturation state earlier when the current on the first conductive cable 211 gradually increases. This not only reduces the magnetic permeability, but also prevents the first magnetic core 110 from entering a saturation state as the current continues to increase. This maintains the filtering function of the first magnetic core 110, reduces the coupling coefficient between the first conductive cable 211, the second conductive cable 221, and the third conductive cable 231, and ensures that the EMC performance of the positive and negative poles of the motor drive remains unchanged.

[0132] In a specific embodiment, by providing a first capacitor 502 connected between the second conductive cable 221 and ground, providing a second capacitor 503 connected between the third conductive cable 231 and ground, and providing a second magnetic core 120 having a magnetic flux density less than the saturation magnetic flux density of the first magnetic core 110 between the first through-hole 210 and the second through-hole 220, the second magnetic core 120 can enter a saturation state in advance when the current on the first conductive cable 211 gradually increases. This not only reduces the magnetic permeability, but also prevents the first magnetic core 110 from entering a saturation state as the current continues to increase, thereby maintaining the filtering function of the first magnetic core 110, reducing the coupling coefficient between the first conductive cable 211, the second conductive cable 221, and the third conductive cable 231, and ensuring that the EMC performance of the positive and negative poles of the motor drive remains unchanged. For example, with the filter structure of the embodiment, when the first conductive wire 211 passes through the first through-hole 210, the second conductive wire 221 passes through the second through-hole 220, and the third conductive wire 231 passes through the third through-hole 230, the coupling coefficient between the first conductive wire 211 and the second conductive wire 221 is approximately 0.393, and the coupling coefficient between the first conductive wire 211 and the third conductive wire 231 is approximately 0.398. The coupling coefficient of the filter core composed of the first magnetic core 110 and the second magnetic core 120 is reduced by approximately 60% compared to the coupling coefficient of the filter core composed of only the first magnetic core 110.

[0133] In some embodiments, the second capacitor 503 can be connected between one end of the third conductive trace 231 and ground.

[0134] In some embodiments, the first capacitor 502 can be connected between one end of the second conductive trace 221 and ground.

[0135] In some embodiments, the number of the second capacitors 503 is at least two, and at least one second capacitor 503 is disposed at both ends of the third conductive trace 231 .

[0136] In some embodiments, the number of the first capacitors 502 is at least two, and at least one first capacitor 502 is disposed at each end of the second conductive trace 221 .

[0137] In some embodiments, the filter structure includes at least two first magnetic cores 101, and the first conductive wire 211, the second conductive wire 221 and the third conductive wire 231 pass through each first magnetic core 101 in sequence through the corresponding through holes, and a second magnetic core 120 is provided between the first through hole 210 and the second through hole 220 in each first magnetic core 101.

[0138] In some embodiments, at least one first capacitor 502 is connected to the second conductive trace 221 between adjacent first magnetic cores 101 .

[0139] In some embodiments, at least one second capacitor 503 is connected to the third conductive trace 231 between adjacent first magnetic cores 101 .

[0140] In some embodiments, the number of the first capacitors 502 is the same as the number of the first magnetic cores 101 , and each first capacitor 502 is connected to the second conductive trace 221 in the corresponding first magnetic core 101 .

[0141] In some embodiments, the number of the second capacitors 503 is the same as the number of the first magnetic cores 101 , and each second capacitor 503 is connected to the third conductive trace 231 in the corresponding first magnetic core 101 .

[0142] An embodiment of the present application further provides a driving device. As shown in FIG10 , the driving device is connected to a battery pack 610 , a charging device 640 , and a motor 620 . The driving device includes a filter structure as described in any one of the above embodiments.

[0143] In this embodiment, the third conductive cable 231 and the second conductive cable 221 are respectively connected to the positive and negative electrodes of the battery pack 610. The positive electrode of the battery pack 610 is connected to the first end of the power module 630 via the third conductive cable 231, and the negative electrode of the battery pack 610 is connected to the second end of the power module 630 via the second conductive cable 221. The power module 630 is connected to the first through-hole 210 via the motor 620. The power module 630 can be composed of multiple bridge arms, and the number of bridge arms corresponds to the phase of the motor 620. The first conductive cable 211, the coil in the motor 620, and the bridge arms in the power module 630 constitute a Boost DC boost circuit.

[0144] For example, in Boost charging mode, the charging device 640 uses the Boost DC boost circuit to boost the 400V voltage to 800V DC to charge the battery pack 610. In motor drive mode, the power module 630 converts the DC power provided by the battery pack 610 into multi-phase AC power and outputs it to the motor 620, driving the motor 620 to operate normally.

[0145] In some embodiments, as shown in FIG11 , the driving device further includes: a DC bus capacitor C2, a power module 630, and a first switch K1; the battery pack 610, the DC bus capacitor C2, and the power module 630 are connected in parallel between the second conductive cable 221 and the third conductive cable 231; a first end of the charging device 640 is connected to the second through-hole 220; a second end of the charging device 640 is connected to the first conductive cable 211 via the first switch K1; the first conductive cable 211 is connected to the power module 630 via the motor 620; the power module 630 drives the motor 620 to operate when the first switch K1 is disconnected; and the charging device 640 charges the battery pack via the first conductive cable 211, the coil of the motor 620, and the power module 630 when the first switch K1 is connected.

[0146] In this embodiment, the operating mode of the driving device can be controlled by turning on and off the first switch K1 and the bridge arm in the power module 630. Specifically, the first conductive cable 211, the coil in the motor 620, and the bridge arm in the power module 630 constitute a Boost DC boost circuit. When the first switch K1 is off, the power module 630 drives the motor 620 to operate; when the first switch K1 is on, the charging device 640 charges the battery pack 610 via the first conductive cable 211, the coil of the motor 620, and the power module 630.

[0147] In some embodiments, the driving device further includes a filter capacitor C1 , and the filter capacitor C1 is connected in parallel to both ends of the charging device 640 .

[0148] In this embodiment, the filter capacitor C1 is connected in parallel to both ends of the charging device 640 to filter the current output by the charging device 640 .

[0149] In some embodiments, the negative output terminal of the charging device 640 is connected to the negative electrode of the battery pack 610 , and the positive output terminal of the charging device 640 is connected to the first switch K1 .

[0150] In some embodiments, as shown in Figure 10, the power module 630 includes a first switch tube Q1, a second switch tube Q2, a third switch tube Q3, a fourth switch tube Q4, a fifth switch tube Q5 and a sixth switch tube Q6. The first switch tube Q1 and the second switch tube Q2 are connected in series to form a first bridge arm, the third switch tube Q3 and the fourth switch tube Q4 are connected in series to form a second bridge arm, and the fifth switch tube Q5 and the sixth switch tube Q6 are connected in series to form a third bridge arm. The common node of the first switch tube Q1 and the second switch tube Q2 is connected to the coil W in the motor, the common node of the third switch tube Q3 and the fourth switch tube Q4 is connected to the coil V in the motor, and the common node of the fifth switch tube Q5 and the sixth switch tube Q6 is connected to the coil U in the motor. One end of the coil U, coil V and coil W of the motor is connected to the node N.

[0151] The present application also provides a motor drive system comprising: a battery pack, a charging device, a motor, and a filter structure as described in any of the above embodiments. As shown in FIG10 , a third conductive cable 231 and a second conductive cable 221 are connected to the positive and negative electrodes of a battery pack 610, respectively. The positive electrode of the battery pack 610 is connected to the first end of a power module 630 via the third conductive cable 231, and the negative electrode of the battery pack 610 is connected to the second end of the power module 630 via the second conductive cable 221. The power module 630 is connected to the first conductive cable 211 via a motor 620. The power module 630 may be composed of multiple bridge arms, the number of which corresponds to the phase of the motor 620. The first conductive cable 211, the coils within the motor 620, and the bridge arms within the power module 630 constitute a Boost DC boost circuit.

[0152] For example, in Boost charging mode, the charging device 640 uses the Boost DC boost circuit to boost the 400V voltage to 800V DC to charge the battery pack 610. In motor drive mode, the power module 630 converts the DC power provided by the battery pack 610 into multi-phase AC power and outputs it to the motor 620, driving the motor 620 to operate normally.

[0153] In some embodiments, as shown in FIG10 , the driving device further includes: a DC bus capacitor C2, a power module 630, and a first switch K1; the battery pack 610, the DC bus capacitor C2, and the power module 630 are connected in parallel between the second conductive cable 221 and the third conductive cable 231; a first end of the charging device 640 is connected to the second conductive cable 221, and a second end of the charging device 640 is connected to the first conductive cable 211 via the first switch K1; the first conductive cable 211 is connected to the power module 630 via the motor 620; the power module 630 drives the motor 620 to operate when the first switch K1 is disconnected; and the charging device 640 charges the battery pack via the first conductive cable 211, the coil of the motor 620, and the power module 630 when the first switch K1 is connected.

[0154] In this embodiment, the operating mode of the driving device can be controlled by turning on and off the first switch K1 and the bridge arm in the power module 630. Specifically, the first conductive cable 211, the coil in the motor 620, and the bridge arm in the power module 630 constitute a Boost DC boost circuit. When the first switch K1 is off, the power module 630 drives the motor 620 to operate; when the first switch K1 is on, the charging device 640 charges the battery pack 610 via the first conductive cable 211, the coil of the motor 620, and the power module 630.

[0155] In some embodiments, the driving device further includes a filter capacitor C1 , and the filter capacitor C1 is connected in parallel to both ends of the charging device 640 .

[0156] In this embodiment, the filter capacitor C1 is connected in parallel to both ends of the charging device 640 to filter the current output by the charging device 640 .

[0157] In some embodiments, the negative output terminal of the charging device 640 is connected to the negative electrode of the battery pack 610 , and the positive output terminal of the charging device 640 is connected to the first switch K1 .

[0158] In some embodiments, as shown in Figure 10, the power module 630 includes a first switch tube Q1, a second switch tube Q2, a third switch tube Q3, a fourth switch tube Q4, a fifth switch tube Q5 and a sixth switch tube Q6. The first switch tube Q1 and the second switch tube Q2 are connected in series to form a first bridge arm, the third switch tube Q3 and the fourth switch tube Q4 are connected in series to form a second bridge arm, and the fifth switch tube Q5 and the sixth switch tube Q6 are connected in series to form a third bridge arm. The common node of the first switch tube Q1 and the second switch tube Q2 is connected to the coil W in the motor, the common node of the third switch tube Q3 and the fourth switch tube Q4 is connected to the coil V in the motor, and the common node of the fifth switch tube Q5 and the sixth switch tube Q6 is connected to the coil U in the motor. One end of the coil U, coil V and coil W of the motor is connected to the node N.

[0159] In the technical solution of the embodiment of the present application, the filter structure includes a first magnetic core and a second magnetic core. The first magnetic core includes a first through hole, a second through hole, and a third through hole. The first through hole is used to pass the first conductive cable, the second through hole is used to pass the second conductive cable, and the third through hole is used to pass the third conductive cable. A second magnetic core is provided between the first through hole and the second through hole. By setting the saturation magnetic flux density of the second magnetic core to be smaller than the saturation magnetic flux density of the first magnetic core, the second magnetic core can enter a saturation state in advance when the current on the conductive cable gradually increases, which not only reduces the magnetic permeability, but also prevents the first magnetic core from entering a saturation state as the current continues to increase, thereby maintaining the filtering function of the first magnetic core, thereby reducing the coupling coefficient between the first conductive cable, the second conductive cable, and the third conductive cable, thereby ensuring that the EMC performance of the positive and negative poles of the motor drive remains unchanged.

[0160] Those skilled in the art can clearly understand that, for the convenience and brevity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0161] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant description of other embodiments.

[0162] In the embodiments provided in this application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the electronic device embodiments described above are merely illustrative. For example, the division of modules or units is only a logical function division, and there may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0163] Units described as separate components may or may not be physically separate, and components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0164] In addition, the functional units in the various embodiments of the present application may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0165] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application 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. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. A filter structure, wherein: include: a first magnetic core and a second magnetic core; The first magnetic core includes a first through hole, a second through hole, and a third through hole, wherein the first through hole is used to pass the first conductive cable, the second through hole is used to pass the second conductive cable, and the third through hole is used to pass the third conductive cable; The second magnetic core is disposed between the first through hole and the second through hole, and a saturation magnetic flux density of the second magnetic core is smaller than a saturation magnetic flux density of the first magnetic core.

2. The filter structure according to claim 1, wherein The second through hole and the third through hole are connected via a magnetic core air gap.

3. The filter structure according to claim 1, wherein: An angle between an axis of symmetry of a cross section of the second through hole and an axis of symmetry of a cross section of the third through hole is any angle between 0° and 180°.

4. The filter structure according to claim 1, wherein The symmetry axis of the cross section of the second through hole and the symmetry axis of the cross section of the third through hole are parallel to each other; and / or An axis of symmetry of a cross section of the second through hole is parallel to an axis of symmetry of a cross section of the first through hole.

5. The filter structure according to claim 1, wherein The symmetry axis of the cross section of the second through hole and the symmetry axis of the cross section of the third through hole are perpendicular to each other; and / or An axis of symmetry of a cross section of the second through hole is perpendicular to an axis of symmetry of a cross section of the first through hole.

6. The filter structure according to claim 1, wherein: The height of the second magnetic core is greater than the height of the first through hole or greater than the height of the second through hole.

7. The filter structure according to claim 1, wherein: A third magnetic core is provided between the second through hole and the third through hole.

8. The filter structure according to claim 7, wherein: At least one of the first side of the third magnetic core and the second side of the third magnetic core is provided with a first air gap; a line connecting the first side of the third magnetic core and the second side of the third magnetic core intersects a line connecting the second through hole and the third through hole.

9. The filter structure according to claim 7, wherein: At least one second air gap is provided in the third magnetic core, and the second air gap connects the second through hole and the third through hole.

10. The filter structure according to claim 9, wherein: When there are multiple second air gaps, the second air gaps are evenly distributed.

11. The filter structure according to any one of claims 1 to 10, wherein: The first magnetic core is polygonal or elliptical.

12. The filter structure according to any one of claims 1 to 10, wherein: An insulating medium is filled between the first through hole and the first magnetic core; and / or An insulating medium is filled between the second through hole and the first magnetic core; and / or An insulating medium is filled between the third through hole and the first magnetic core.

13. The filter structure according to claim 12, wherein: The insulating medium is insulating gas or insulating components.

14. The filter structure according to any one of claims 1 to 10, wherein: The first magnetic core is made of nanocrystalline material or high magnetic flux density ferrite material.

15. The filter structure according to claim 14, wherein: The second magnetic core is made of a ferrite material with low magnetic flux density.

16. A filter circuit, wherein: The filter structure comprises a first conductive wire, a second conductive wire, a third conductive wire, and the filter structure according to any one of claims 1 to 15, wherein the first conductive wire passes through the first through hole, the second conductive wire passes through the second through hole, and the third conductive wire passes through the third through hole.

17. The filter circuit according to claim 16, wherein: The filtering circuit further includes: at least one first capacitor connected between the second conductive wire and ground; and / or, At least one second capacitor is connected between the third conductive line and ground.

18. A driving device, wherein: Used to connect with a battery pack, a charging device and a motor, the driving device includes the filter structure according to any one of claims 1 to 15, or includes the filter circuit according to claim 16 or 17.

19. The driving device according to claim 18, wherein: The driving device further includes: a DC bus capacitor, a power module, and a first switch; The battery pack, the DC bus capacitor, and the power module are connected in parallel between the second conductive cable and the third conductive cable. The first end of the charging device is connected to the second conductive cable, the second end of the charging device is connected to the first conductive cable via the first switch, and the first conductive cable is connected to the power module via the motor. The power module is used to drive the motor to work when the first switch is disconnected; The charging device is used to charge the battery pack via the first conductive cable, the coil of the motor, and the power module when the first switch is turned on.

20. The driving device according to claim 18, wherein The driving device further includes a filter capacitor connected in parallel to both ends of the charging device.

21. A motor drive system, wherein: include: Battery pack, charging device, motor; as well as The filter structure according to any one of claims 1 to 15, or The filter circuit according to claim 16 or 17, or A drive device as claimed in any one of claims 18 to 20.

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