Filter circuit and filter

Abstract

The utility model relates to a filter circuit and a filter. The filter circuit comprises a conductive element, a common mode inductor and a capacitance circuit; the first ends of a first conductive element and a second conductive element in the conductive elements are connected with the supporting capacitor, the second ends are connected with the high-voltage port, and the common-mode inductor performs first common-mode filtering on electromagnetic interference carried by direct current; a first end of a first capacitor in the capacitor circuit is connected with the first conductive element, and a second end of the first capacitor is grounded; the first end of the second capacitor is connected with the second conductive element, and the second end of the second capacitor is grounded so as to carry out second common-mode filtering on the electromagnetic interference; the first end of the third capacitor and the first end of the fourth capacitor are both connected with the first conductive element, and the second end of the third capacitor and the second end of the fourth capacitor are both connected with the second conductive element so as to carry out differential mode filtering on electromagnetic interference. By adopting the filter circuit, the interference of electromagnetic interference of an electric driving system of a new energy automobile on the automobile can be reduced.

Description

Technical Field

[0001] The present application relates to the technical field of new energy vehicles, and in particular to a filtering circuit and a filter. Background Art

[0002] New energy vehicles are a very important development direction for the automotive industry. New energy vehicles are composed of a three-electric system consisting of batteries, motors and motor controllers as their main electric drive system, but motor controllers working with high current and high switching frequency will inevitably produce conducted interference and radiated interference. The electromagnetic interference caused by these interferences will affect the CAN and LIN bus communications of other electronic components in the car, thereby causing malfunctions of the control system and endangering the life safety of users. Therefore, how to reduce the electromagnetic interference of the electric drive system of new energy vehicles on the vehicle needs to be solved urgently. Utility Model Content

[0003] Based on this, it is necessary to provide a filter circuit and filter that can reduce the electromagnetic interference of the electric drive system of new energy vehicles on the vehicle in order to solve the above technical problems.

[0004] In a first aspect, the present application provides a filter circuit, the filter circuit comprising:

[0005] A conductive element, the conductive element comprising a first conductive element and a second conductive element, wherein the first ends of the first conductive element and the second conductive element are both connected to the support capacitor, and the second ends of the first conductive element and the second conductive element are both connected to the high voltage port;

[0006] A common mode inductor connected to both the first conductive element and the second conductive element to perform a first common mode filtering process on electromagnetic interference carried by the direct current input from the support capacitor;

[0007] A capacitor circuit is provided between the common-mode inductor and the high-voltage port, and includes a first capacitor, a second capacitor, a third capacitor and a fourth capacitor; wherein the first end of the first capacitor is connected to the first conductive element, and the second end of the first capacitor is grounded; the first end of the second capacitor is connected to the second conductive element, and the second end of the second capacitor is grounded, so as to perform a second common-mode filtering process on the electromagnetic interference carried by the direct current through the first capacitor and the second capacitor; the first end of the third capacitor and the first end of the fourth capacitor are both connected to the first conductive element, and the second end of the third capacitor and the second end of the fourth capacitor are both connected to the second conductive element, so as to perform a differential-mode filtering process on the electromagnetic interference carried by the direct current through the third capacitor and the fourth capacitor.

[0008] In one embodiment, the filter circuit further includes a third conductive element and a fourth conductive element; a fifth conductive element and a sixth conductive element;

[0009] The first end of the third conductive element is connected to the first conductive element; the second end of the third conductive element is connected to the first end of the first capacitor, so that the first capacitor is connected to the first conductive element through the third conductive element;

[0010] The first end of the fourth conductive element is connected to the second conductive element; the second end of the fourth conductive element is connected to the first end of the second capacitor; so that the second capacitor is connected to the second conductive element through the fourth conductive element.

[0011] In one of the embodiments, the filter circuit further includes a fifth conductive element and a sixth conductive element;

[0012] The first end of the fifth conductive element is connected to the second end of the first capacitor; the second end of the fifth conductive element is grounded, so that the second end of the first capacitor is grounded through the fifth conductive element;

[0013] The first end of the sixth conductive element is connected to the second end of the second capacitor; the second end of the sixth conductive element is grounded, so that the second end of the second capacitor is grounded through the sixth conductive element.

[0014] In one of the embodiments, the filter circuit further includes a seventh conductive element and an eighth conductive element;

[0015] The first end of the seventh conductive element is connected to the first conductive element; the first end of the third capacitor and the first end of the fourth capacitor are both connected to the second end of the seventh conductive element, so as to be connected to the first conductive element through the seventh conductive element;

[0016] The first end of the eighth conductive element is connected to the second conductive element; the second end of the third capacitor and the second end of the fourth capacitor are both connected to the second end of the eighth conductive element, so as to be connected to the second conductive element through the eighth conductive element.

[0017] In one embodiment, the third conductive element is a first connecting copper bar, and the fourth conductive element is a second connecting copper bar;

[0018] The second end of the first connecting copper bar connected to the first end of the first capacitor is in a Y shape;

[0019] The second end of the second connecting copper bar connected to the first end of the second capacitor is in a Y shape.

[0020] In one embodiment, the fifth conductive element is a first grounding copper bar, and the sixth conductive element is a second grounding copper bar;

[0021] The second end of the grounded first grounding copper bar is in a ring shape; the first end of the first connecting copper bar connected to the second end of the first capacitor is in a Y shape;

[0022] The second end of the grounded second grounding copper bar is in a ring shape; the first end of the second connecting copper bar connected to the second end of the second capacitor is in a Y shape.

[0023] In one embodiment, the common mode inductor is a magnetic ring.

[0024] In one embodiment, the first conductive element is a positive busbar, and the second conductive element is a negative busbar; or,

[0025] The first conductive element and the second conductive element are cables; two ends of the two cables are located on two sides of the magnetic ring.

[0026] In one embodiment,

[0027] The first capacitor and the second capacitor are configured to filter out common mode interference within a frequency band of 1 MHz to 3 MHz;

[0028] The third capacitor is configured to filter out differential mode interference within a frequency band of 6 MHz to 10 MHz;

[0029] The fourth capacitor is configured to filter out differential mode interference within a frequency band of 30 MHz to 50 MHz.

[0030] In a second aspect, the present application also provides a filter, which includes an insulating shell and a filter circuit as described in any one of the first aspects above; wherein the first ends of the first conductive element and the second conductive element in the filter circuit are located outside the insulating shell and are both connected to the supporting capacitor; the second ends of the first conductive element and the second conductive element are located outside the insulating shell and are both connected to the high-voltage port.

[0031] The above-mentioned filtering circuit and filter, the filtering circuit includes: a conductive element, a common-mode inductor and a capacitor circuit, wherein the conductive element includes a first conductive element and a second conductive element, the first ends of the first conductive element and the second conductive element are both connected to the support capacitor, and the second ends are both connected to the high-voltage port; the common-mode inductor is connected to the first conductive element and the second conductive element to perform a first common-mode filtering process on the electromagnetic interference carried by the direct current input from the support capacitor; the capacitor circuit is arranged between the common-mode inductor and the high-voltage port, and the capacitor circuit includes a first capacitor, a second capacitor, a third capacitor and a fourth capacitor; wherein the first end of the first capacitor is connected to the first conductive element, and the second end of the first capacitor is grounded; the first end of the second capacitor is connected to the second conductive element, and the second end of the second capacitor is grounded, so as to perform a second common-mode filtering process on the electromagnetic interference carried by the direct current through the first capacitor and the second capacitor; the first end of the third capacitor and the first end of the fourth capacitor are both connected to the first conductive element, and the second end of the third capacitor and the second end of the fourth capacitor are both connected to the second conductive element, so as to perform a differential-mode filtering process on the electromagnetic interference carried by the direct current through the third capacitor and the fourth capacitor. In this way, the electromagnetic interference carried by the direct current input from the supporting capacitor can be common-mode filtered through the common-mode inductor, the first capacitor and the second capacitor, and then differential-mode filtered through the third capacitor and the fourth capacitor, thereby effectively filtering out the electromagnetic interference and reducing the interference of the electromagnetic interference of the electric drive system of the new energy vehicle to the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 is a schematic diagram of the circuit structure of a filter circuit in an embodiment;

[0034] Figure 2 is a circuit structure schematic diagram of another filter circuit in an embodiment;

[0035] Figure 3 is a circuit structure schematic diagram of another filter circuit in an embodiment;

[0036] Figure 4 is a circuit structure schematic diagram of another filter circuit in an embodiment;

[0037] Figure 5 is a circuit structure schematic diagram of another filter circuit in an embodiment;

[0038] Figure 6A schematic diagram of a process of electromagnetic interference filtering in one embodiment;

[0039] Figure 7 is a schematic diagram of the structure of a filter in one embodiment;

[0040] Figure 8 is a schematic diagram of the structure of another filter in one embodiment;

[0041] Fig. 9 is a schematic diagram of electromagnetic interference test results in one embodiment;

[0042] Fig.10 A schematic diagram of another electromagnetic interference test result in an embodiment. DETAILED DESCRIPTION

[0043] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. It should be understood that many specific details are set forth in the following description to facilitate a full understanding of the present application, but the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0045] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0046] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0047] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0048] It is understood that the terms "first", "second", etc. used in this application may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish a first element from another element. For example, without departing from the scope of this application, a first resistor may be referred to as a second resistor, and similarly, a second resistor may be referred to as a first resistor. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

[0049] It can be understood that “at least one” means one or more, “plurality” means two or more, and “at least a portion of an element” means a part or all of an element.

[0050] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. At the same time, the term "and / or" used in this specification includes any and all combinations of the relevant listed items.

[0051] New energy vehicles are a very important development direction for the automotive industry. New energy vehicles are composed of a three-electric system consisting of batteries, motors and motor controllers as their main electric drive systems. However, motor controllers operating at high currents and high switching frequencies will inevitably generate conducted interference and radiated interference, and these electromagnetic interferences will affect the CAN and LIN communications of other electronic components in the vehicle, thereby causing malfunctions of the control system and endangering the lives of users. For example, the inverter module in the electric drive system usually contains multiple IGBTs (Insulated Gate Bipolar Transistors). IGBTs generate radio frequency interference during high-speed switching on and off. Some radio frequency interference propagates from the inverter module to the DC power supply end, which will have an adverse effect on other electronic components. How to solve the electromagnetic compatibility problem of new energy vehicles in the design is an important factor affecting the reliability of new energy vehicles. Based on this, how to reduce the interference of electromagnetic interference of the electric drive system of new energy vehicles to the vehicle needs to be solved urgently.

[0052] In view of this, an embodiment of the present application provides a filter circuit, which can filter the electromagnetic interference generated by the electric drive system and reduce the interference of the electromagnetic interference to the vehicle.

[0053] In one embodiment, Figure 1 As shown, a circuit structure schematic diagram of a filter circuit is provided, which includes a conductive element, a common-mode inductor L and a capacitor circuit, wherein the conductive element includes a first conductive element 101 and a second conductive element 102, and the capacitor circuit includes a first capacitor C1, a second capacitor C2, a third capacitor C3 and a fourth capacitor C4. The first ends of the first conductive element 101 and the second conductive element 102 are both connected to the support capacitor P1, and the second ends are both connected to the high-voltage port P2; the common-mode inductor L is connected to the first conductive element 101 and the second conductive element 102 to perform a first common-mode filtering process on the electromagnetic interference carried by the direct current input from the support capacitor; the capacitor circuit is arranged between the common-mode inductor L and the high-voltage port, the first end of the first capacitor C1 is connected to the first conductive element 101, and the second end of the first capacitor C1 is grounded; the first end of the second capacitor C2 is connected to the second conductive element 102, and the second end of the second capacitor C2 is grounded, so as to perform a second common-mode filtering process on the electromagnetic interference carried by the direct current through the first capacitor C1 and the second capacitor C2; the first end of the third capacitor C3 and the first end of the fourth capacitor C4 are both connected to the first conductive element 101, and the second end of the third capacitor C3 and the second end of the fourth capacitor C4 are both connected to the second conductive element 102, so as to perform a differential-mode filtering process on the electromagnetic interference carried by the direct current through the third capacitor C3 and the fourth capacitor C4.

[0054] The support capacitor is a component in the electric drive system, and the high-voltage port is a current transmission port in the electric drive system. The filter circuit can be connected between the two to filter the electromagnetic interference carried by the direct current transmitted between the two.

[0055] For example, Figure 1 As shown, there may be two supporting capacitors, and the first conductive element 101 and the second conductive element 102 are connected to the two P1s respectively. Similarly, there may be two high-voltage ports, and the first conductive element 101 and the second conductive element 102 are connected to the two P2s respectively.

[0056] refer to Figure 1 The electromagnetic interference generated by the IGBT passes through the common mode inductor L along with the direct current to perform the first common mode filtering process. The common mode inductor L has the function of increasing the impedance of the common mode loop and reducing the current of the common mode loop to attenuate the common mode interference.

[0057] Optionally, the common mode inductor L is a magnetic ring, or other components that can achieve this function. Optionally, the material of the magnetic ring is generally nanocrystal or ferrite.

[0058] After the direct current containing electromagnetic interference undergoes the first common-mode filtering process through the common-mode inductor L, it continues to be transmitted along the first conductive element 101 and the second conductive element 102, and when passing through C1 and C2, C1 and C2 undergo the second common-mode filtering process. Among them, C1 and C2, as common-mode capacitors, can introduce electromagnetic interference into the ground plane and can attenuate the common-mode interference. Therefore, the electromagnetic interference carried by the direct current is attenuated again under the action of C1 and C2.

[0059] Optionally, the frequency bands of electromagnetic interference filtered by the common mode inductors L, C1 and C2 may be different. Optionally, the capacitance values ​​of C1 and C2 are the same.

[0060] In addition, C3 and C4, as differential mode capacitors, can attenuate differential mode interference. Therefore, electromagnetic interference continues to attenuate under the action of C3 and C4. Figure 1 , electromagnetic interference can be attenuated first under the action of C4, and then under the action of C3.

[0061] Optionally, the frequency bands of electromagnetic interference filtered by C3 and C4 may be different. Optionally, the capacitance values ​​of C3 and C4 are different.

[0062] In addition, the common mode inductor L, the first capacitor C1, the second capacitor C2, the third capacitor C3 and the fourth capacitor C4 form an LC filter, which can attenuate common mode interference.

[0063] In general, the electromagnetic interference generated by the inverter module of the electric drive system is first attenuated under the action of the first-stage common-mode filter module (that is, the common-mode inductor L), then attenuated under the action of the second-stage common-mode filter module (that is, the first capacitor C1 and the second capacitor C2), then attenuated under the action of the first-stage differential-mode filter module (that is, the fourth capacitor C4), and then attenuated under the action of the second-stage differential-mode filter module (that is, the third capacitor C3). That is, the electromagnetic interference generated by the inverter module of the electric drive system can be reduced to a very low level after two common-mode filters and two differential-mode filters.

[0064] The above-mentioned filtering circuit includes a conductive element, a common-mode inductor L and a capacitor circuit, wherein the conductive element includes a first conductive element 101 and a second conductive element 102, the first ends of the first conductive element 101 and the second conductive element 102 are both connected to the support capacitor, and the second ends are both connected to the high-voltage port; the common-mode inductor L is connected to the first conductive element 101 and the second conductive element 102 to perform a first common-mode filtering process on the electromagnetic interference carried by the direct current input from the support capacitor; the capacitor circuit is arranged between the common-mode inductor L and the high-voltage port, and the capacitor circuit includes a first capacitor C1, a second capacitor C2, a third capacitor C3 and a fourth capacitor C4; wherein, the first A first end of a capacitor C1 is connected to the first conductive element 101, and a second end of the first capacitor C1 is grounded; a first end of a second capacitor C2 is connected to the second conductive element 102, and a second end of the second capacitor C2 is grounded, so that a second common-mode filtering process is performed on the electromagnetic interference carried by the direct current through the first capacitor C1 and the second capacitor C2; a first end of a third capacitor C3 and a first end of a fourth capacitor C4 are both connected to the first conductive element 101, and a second end of the third capacitor C3 and a second end of the fourth capacitor C4 are both connected to the second conductive element 102, so that a differential-mode filtering process is performed on the electromagnetic interference carried by the direct current through the third capacitor C3 and the fourth capacitor C4. Among them, the magnetic ring can increase the impedance of the common-mode loop, reduce the current of the common-mode loop, and can attenuate the common-mode interference. The first capacitor C1 and the second capacitor C2 act as common-mode capacitors to introduce electromagnetic interference into the ground plane, which can attenuate the common-mode interference. The third capacitor C3 and the fourth capacitor C4 act as differential-mode capacitors to attenuate differential-mode interference. By performing two common-mode filtering and two differential-mode filtering on the electromagnetic interference generated by the inverter module of the electric drive system, the forward-propagating electromagnetic interference can be greatly reduced, and the interference of the electromagnetic interference of the electric drive system of the new energy vehicle to the vehicle can be reduced.

[0065] In one embodiment, please refer to Figure 2, which shows a circuit structure diagram of another filter circuit provided by an embodiment of the present application. The filter circuit further includes a third conductive element 103 and a fourth conductive element 104; the first end of the third conductive element 103 is connected to the first conductive element 101; the second end of the third conductive element 103 is connected to the first end of the first capacitor C1, so that the first capacitor is connected to the first conductive element through the third conductive element; the first end of the fourth conductive element 104 is connected to the second conductive element 102; the second end of the fourth conductive element 104 is connected to the first end of the second capacitor C2, so that the second capacitor is connected to the second conductive element through the fourth conductive element.

[0066] As mentioned above, the capacitor circuit is arranged between the common mode inductor L and the high voltage port, and the first end of the third conductive element 103 is connected to the first conductive element 101, that is, the first end of the third conductive element 103 is connected to the portion of the first conductive element 101 located between the common mode inductor L and the high voltage port. Similarly, the first end of the fourth conductive element 104 is connected to the second conductive element 102, that is, the first end of the fourth conductive element 104 is connected to the portion of the second conductive element 102 located between the common mode inductor L and the high voltage port.

[0067] In the embodiment of the present application, by providing the third conductive element 103 and the fourth conductive element 104 , it can be ensured that the connection between each capacitor and the first conductive element 101 and the second conductive element 102 is more secure, thereby ensuring the quality of the filtering process.

[0068] In one embodiment, please refer to Figure 3 , which shows a circuit structure diagram of another filter circuit provided by an embodiment of the present application. The filter circuit also includes a fifth conductive element 105 and a sixth conductive element 106; the first end of the fifth conductive element 105 is connected to the second end of the first capacitor C1; the second end of the fifth conductive element 105 is grounded, so that the second end of the first capacitor C1 is grounded through the fifth conductive element 105; the first end of the sixth conductive element 106 is connected to the second end of the second capacitor C2; the second end of the sixth conductive element 106 is grounded, so that the second end of the second capacitor C2 is grounded through the sixth conductive element 106.

[0069] In the embodiment of the present application, by providing the fifth conductive element 105 and the sixth conductive element 106 , it can be ensured that each capacitor is more firmly grounded, thereby ensuring the quality of the filtering process.

[0070] In one embodiment, please refer to Figure 4 , which shows a circuit structure diagram of another filter circuit provided in an embodiment of the present application. The filter circuit also includes a seventh conductive element 107 and an eighth conductive element 108;

[0071] The first end of the seventh conductive element 107 is connected to the first conductive element; the first end of the third capacitor and the first end of the fourth capacitor are both connected to the second end of the seventh conductive element 107, so as to be connected to the first conductive element through the seventh conductive element 107;

[0072] The first end of the eighth conductive element 108 is connected to the second conductive element; the second end of the third capacitor and the second end of the fourth capacitor are both connected to the second end of the eighth conductive element 108 to be connected to the second conductive element through the eighth conductive element 108 .

[0073] In the embodiment of the present application, by providing the seventh conductive element 107 and the eighth conductive element 108, it can be ensured that the third capacitor and the fourth capacitor are more firmly connected to the first conductive element and the second conductive element, thereby ensuring the quality of the filtering process.

[0074] In one embodiment, the third conductive element 103 is a first connecting copper bar, and the fourth conductive element 104 is a second connecting copper bar; the second end of the first connecting copper bar connected to the first end of the first capacitor C1 is Y-shaped; the second end of the second connecting copper bar connected to the first end of the second capacitor C2 is Y-shaped.

[0075] In other words, the first end of the first connecting copper bar is welded to the first conductive element 101, and the second end is welded to a pin of C1; the first end of the second connecting copper bar is welded to the second conductive element 102, and the second end is welded to a pin of C2. The ends of the first connecting copper bar and the second connecting copper bar welded to the capacitor pin are in a Y shape, which is conducive to the positioning and welding of the capacitor pin.

[0076] Optionally, the seventh conductive element 107 and the eighth conductive element 108 may also be connecting copper bars.

[0077] In one embodiment, the fifth conductive element 105 is a first grounding copper bar, and the sixth conductive element 106 is a second grounding copper bar; the second end of the grounded first grounding copper bar is in a circular ring shape; the first end of the first grounding copper bar connected to the second end of the first capacitor C1 is in a Y shape; the second end of the grounded second grounding copper bar is in a circular ring shape; the first end of the second grounding copper bar connected to the second end of the second capacitor C2 is in a Y shape.

[0078] In other words, one end of the grounding copper bar is in a ring shape, and the other end is in a Y shape. Among them, the ring-shaped end of the first grounding copper bar is connected to the housing of the controller through a fastener (such as a screw) to be grounded; the other end is in a Y shape and welded to another pin of C1; the ring-shaped end of the second grounding copper bar is connected to the housing of the controller through a fastener (such as a screw) to be grounded; the other end is in a Y shape and welded to another pin of C2, which is conducive to the positioning and welding of the capacitor pins. Among them, the controller is a component in the circuit drive system, and the filter can be set in the controller.

[0079] In one embodiment, the first conductive element 101 is a positive bus bar, and the second conductive element 102 is a negative bus bar.

[0080] As mentioned above, there can be two supporting capacitors, and the first conductive element 101 and the second conductive element 102 are connected to the two P1s respectively. In other words, one of the two supporting capacitors is positive and the other is negative, the first conductive element 101 is the positive busbar, and the first conductive element 101 is connected to the positive P1, and the second conductive element 102 is the negative busbar, and the second conductive element 102 is connected to the negative P1.

[0081] Among them, the common-mode inductor L is a magnetic ring, and when the first conductive element 101 is the positive busbar and the second conductive element 102 is the negative busbar, the first ends of the two busbars pass through the magnetic ring so that the common-mode inductor L is connected between the supporting capacitor and the high-voltage port, and the common-mode inductor L is connected to the first conductive element 101 and the second conductive element 102.

[0082] In one embodiment, the first conductive element 101 and the second conductive element 102 are cables; the two ends of the two cables are located on both sides of the magnetic ring. When the common mode inductor L is a magnetic ring, the first ends of the two cables can pass through the magnetic ring, so that the two ends of the two cables can be located on both sides of the magnetic ring, so that the magnetic ring is connected between the supporting capacitor and the high voltage port, and the magnetic ring is connected to the first conductive element 101 and the second conductive element 102.

[0083] In one embodiment, the first capacitor C1 and the second capacitor C2 are common mode capacitors, and the third capacitor C3 and the fourth capacitor C4 are differential mode capacitors.

[0084] In one embodiment, the first capacitor C1 and the second capacitor C2 are configured to filter out common-mode interference in the 1MHz to 3MHz frequency band; the third capacitor C3 is configured to filter out differential-mode interference in the 6MHz to 10MHz frequency band; and the fourth capacitor C4 is configured to filter out differential-mode interference in the 30MHz to 50MHz frequency band.

[0085] In this way, the interference in different frequency bands is filtered out by configuring the capacitors, thereby increasing the filtering range of the filter and ensuring that the electromagnetic interference can be effectively filtered out.

[0086] In one embodiment, a filter is provided, the filter comprising an insulating housing and a filter circuit as described in any of the above embodiments; wherein the first ends of the first conductive element and the second conductive element in the filter circuit are located outside the insulating housing and are both connected to the support capacitor; the second ends of the first conductive element and the second conductive element are located outside the insulating housing and are both connected to the high-voltage port. Other elements may be located inside the insulating housing.

[0087] For ease of understanding, the filter circuit and filter provided by the present application are described below with a complete embodiment.

[0088] The present application aims to provide a filter circuit and filter for use in a new energy vehicle electric drive system to reduce electromagnetic interference of the electric drive system. Figure 5 As shown, 1 and 2 are two conductive elements, L is a common mode inductor, C1 and C2 are common mode capacitors, and C3 and C4 are differential mode capacitors. The common mode inductor L can be a magnetic ring, and the conductive elements 1 and 2 pass through the magnetic ring. The magnetic ring can increase the impedance of the common mode loop and reduce the current of the common mode loop, thereby attenuating the common mode interference. One end of the common mode capacitor C1 is connected to the conductive element 1 and the other end is grounded; one end of the common mode capacitor C2 is connected to the conductive element 2 and the other end is grounded; the common mode capacitors C1 and C2 can attenuate the common mode interference. The differential mode capacitors C3 and C4 are connected between the conductive element 1 and the conductive element 2, and can attenuate the differential mode interference. In addition, the common mode inductor L, the common mode capacitors C1 and C2, and the differential mode capacitors C3 and C4 form an LC type filter, which can attenuate the common mode interference. The conductive element 1 can be a positive busbar, and the conductive element 2 can be a negative busbar.

[0089] The filter circuit further includes a first connecting copper bar, a second connecting copper bar, a third connecting copper bar, a fourth connecting copper bar, a first grounding copper bar and a second grounding copper bar ( Figure 5 One end of C1 is welded to the positive busbar through the first connecting copper bar, and the other end is grounded through the first grounding copper bar. One end of C2 is welded to the negative busbar through the second connecting copper bar, and the other end is grounded through the second grounding copper bar. C3 and C4 both have one pin connected to the third connecting copper bar, thereby connecting to the positive busbar, and the other pin connected to the fourth connecting copper bar, thereby connecting to the negative busbar.

[0090] Specifically, the electromagnetic interference generated by the inverter module of the electric drive system is first attenuated by the first-stage common-mode filter module (that is, the common-mode inductor L), then attenuated by the second-stage common-mode filter module (that is, the common-mode capacitors C1 and C2), then attenuated by the first-stage differential-mode filter module (that is, the differential-mode capacitor C4), and then attenuated by the second-stage differential-mode filter module (that is, the differential-mode capacitor C3). That is, the electromagnetic interference generated by the inverter module of the electric drive system can be reduced to a very low level after two common-mode filters and two differential-mode filters. Figure 6 A schematic diagram of the electromagnetic interference filtering process is shown.

[0091] The structure of the filter provided in this application is as follows Figure 7 and Figure 8As shown, the filter includes a positive busbar 1, a negative busbar 2, a magnetic ring L, a first connecting copper bar 5 and a second connecting copper bar 6, capacitors C1 and C2, a first grounding copper bar 7 and a second grounding copper bar 8, an insulating shell 9, differential mode capacitors C3 and C4, a third connecting copper bar, and a fourth connecting copper bar. The third connecting copper bar and the fourth connecting copper bar are not shown.

[0092] The positive busbar 1 and the negative busbar 2 are located in the insulating shell, one section of which passes through the magnetic ring, and both ends of the device pass through the insulating shell. The positive busbar and the negative busbar can also be located on the surface of the insulating shell.

[0093] Each capacitor and magnetic ring are located in an insulating shell and fixed with a polymer resin insulating material to ensure stability. A mounting hole is opened on the outside of the insulating shell, and the filter can be installed inside the chassis of the electric drive system through fasteners (such as screws).

[0094] One end of the first connecting copper bar 5 is welded to the positive busbar 1, and the other end is welded to a pin of C1; one end of the second connecting copper bar 6 is welded to the positive busbar 2, and the other end is welded to a pin of C2. The ends of the two connecting copper bars welded to the capacitor pins are in a Y shape, which is conducive to the positioning and welding of the capacitor pins.

[0095] One end of the first grounding copper bar 7 is in a circular shape and is located in the insulating housing, connected to the controller housing through a fastener (such as a screw) (grounded), and the other end is in a Y shape, and is welded to the other pin of the capacitor C1 after passing through the insulating housing. One end of the second grounding copper bar 8 is in a circular shape and is located in the insulating housing, connected to the controller housing through a fastener (such as a screw) (grounded), and the other end is in a Y shape, and is welded to the other pin of the capacitor C2 after passing through the insulating housing.

[0096] Differential mode capacitors C3 and C4 each have one pin connected to the positive busbar 3 by a connecting copper bar, and the other pin connected to the negative busbar 4 by a connecting copper bar. The material of the magnetic ring L is generally nanocrystalline or ferrite; the insulating shell can be made by injection molding.

[0097] Please refer to Fig. 9 and Fig.10 A schematic diagram showing the test results of electromagnetic interference, wherein Fig. 9 The electromagnetic interference test results of the electric drive system without the above-mentioned filter circuit are shown. Fig.10 The following are the test results of electromagnetic interference of the electric drive system equipped with the above-mentioned filter circuit. Fig. 9 and Fig.10 In the figure, the horizontal axis is frequency in Hz, and the vertical axis is the conducted emission value in dBuV. Fig. 9 L1 is the peak curve, and L2 is the average curve; Fig.10L3 is the peak curve and L4 is the average curve.

[0098] pass Fig. 9 and Fig.10 By comparison, it can be seen that after the filter circuit and filter provided in this application are set in the electric drive system, electromagnetic interference can be well suppressed, so that the electric drive system can meet the Class 3 level of the CISPR25.2016 standard.

[0099] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0100] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A filter circuit, characterized in that: The filtering circuit comprises: A conductive element, the conductive element comprising a first conductive element and a second conductive element, wherein the first ends of the first conductive element and the second conductive element are both connected to the support capacitor, and the second ends are both connected to the high voltage port; A common mode inductor connected to both the first conductive element and the second conductive element to perform a first common mode filtering process on electromagnetic interference carried by the direct current input from the support capacitor; A capacitor circuit, wherein the capacitor circuit is arranged between the common-mode inductor and the high-voltage port, and the capacitor circuit includes a first capacitor, a second capacitor, a third capacitor and a fourth capacitor; wherein the first end of the first capacitor is connected to the first conductive element, and the second end of the first capacitor is grounded; the first end of the second capacitor is connected to the second conductive element, and the second end of the second capacitor is grounded, so as to perform a second common-mode filtering process on the electromagnetic interference carried by the direct current through the first capacitor and the second capacitor; the first end of the third capacitor and the first end of the fourth capacitor are both connected to the first conductive element, and the second end of the third capacitor and the second end of the fourth capacitor are both connected to the second conductive element, so as to perform a differential-mode filtering process on the electromagnetic interference carried by the direct current through the third capacitor and the fourth capacitor.

2. The filter circuit according to claim 1, characterized in that: The filter circuit further includes a third conductive element and a fourth conductive element; The first end of the third conductive element is connected to the first conductive element; the second end of the third conductive element is connected to the first end of the first capacitor, so that the first capacitor is connected to the first conductive element through the third conductive element; The first end of the fourth conductive element is connected to the second conductive element; the second end of the fourth conductive element is connected to the first end of the second capacitor, so that the second capacitor is connected to the second conductive element through the fourth conductive element.

3. The filter circuit according to claim 1, characterized in that: The filter circuit further includes a fifth conductive element and a sixth conductive element; The first end of the fifth conductive element is connected to the second end of the first capacitor; the second end of the fifth conductive element is grounded, so that the second end of the first capacitor is grounded through the fifth conductive element; The first end of the sixth conductive element is connected to the second end of the second capacitor; the second end of the sixth conductive element is grounded, so that the second end of the second capacitor is grounded through the sixth conductive element.

4. The filter circuit according to claim 1, characterized in that: The filter circuit also includes a seventh conductive element and an eighth conductive element; The first end of the seventh conductive element is connected to the first conductive element; the first end of the third capacitor and the first end of the fourth capacitor are both connected to the second end of the seventh conductive element, so as to be connected to the first conductive element through the seventh conductive element; The first end of the eighth conductive element is connected to the second conductive element; the second end of the third capacitor and the second end of the fourth capacitor are both connected to the second end of the eighth conductive element, so as to be connected to the second conductive element through the eighth conductive element.

5. The filter circuit according to claim 2, characterized in that: The third conductive element is a first connecting copper bar, and the fourth conductive element is a second connecting copper bar; The second end of the first connecting copper bar connected to the first end of the first capacitor is in a Y shape; The second end of the second connecting copper bar connected to the first end of the second capacitor is in a Y shape.

6. The filter circuit according to claim 3, characterized in that: The fifth conductive element is a first grounding copper bar, and the sixth conductive element is a second grounding copper bar; The second end of the first grounding copper bar connected to the ground is in a ring shape; the first end of the first grounding copper bar connected to the second end of the first capacitor is in a Y shape; The second end of the grounded second grounding copper bar is in a ring shape; the first end of the second grounding copper bar connected to the second end of the second capacitor is in a Y shape.

7. The filter circuit according to any one of claims 1 to 6, characterized in that: The common mode inductor is a magnetic ring.

8. The filter circuit according to claim 7, characterized in that: The first conductive element is a positive busbar, and the second conductive element is a negative busbar; or, The first conductive element and the second conductive element are cables; two ends of the two cables are located on two sides of the magnetic ring.

9. The filter circuit according to any one of claims 1 to 6, characterized in that: The first capacitor and the second capacitor are configured to filter out common mode interference in a frequency band from 1 MHz to 3 MHz; The third capacitor is configured to filter out differential mode interference in a frequency band from 6 MHz to 10 MHz; The fourth capacitor is configured to filter out differential mode interference within a frequency band of 30 MHz to 50 MHz.

10. A filter, characterized in that: The filter comprises an insulating housing and a filter circuit as claimed in any one of claims 1 to 9; Among them, the first ends of the first conductive element and the second conductive element in the filter circuit are located outside the insulating shell and are both connected to the supporting capacitor; the second ends of the first conductive element and the second conductive element are located outside the insulating shell and are both connected to the high-voltage port.

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