Class Y Capacitors and Inverters

Abstract

A class Y capacitor (1, 7, 12, 16, 27) is disclosed that can be connected between a line and ground, the class Y capacitor (1, 7, 12, 16, 27) comprising first and second conductors (2, 3) separated by a dielectric medium, the first conductor (2) being connected to a first leg (4, 8, 9, 13, 18) and the second conductor (3) being connected to a second leg (5, 10, 11, 19), the first leg (4, 8, 9, 13, 18) having a larger cross section than the second leg (5, 10, 11, 19). Also disclosed is an inverter (23) having the class Y capacitor (1, 7, 12, 16, 27).

Description

[Technical Field]

[0001] The present invention relates to a class Y capacitor that can be connected between a line and ground, the class Y capacitor comprising first and second conductors separated by a dielectric medium, the first conductor being connected to a first leg and the second conductor being connected to a second leg. [Background technology]

[0002] To prevent or minimize the adverse effects of electromagnetic and radio frequency interference, a class Y capacitor, also known as a "line to ground capacitor," may be placed between the line and ground. Summary of the Invention [Problem to be solved by the invention]

[0003] Class Y capacitors are used as filter components in high-voltage electrical equipment in automobiles. Currently, there is a trend toward higher voltages, higher switching frequencies, and faster switching speeds. When using conventional Class Y capacitors, they tend to overheat due to a loss of filtering function, which can lead to failure. Therefore, the operating temperature of Class Y capacitors must be kept below certain limits. Most Class Y capacitors have a plastic housing, which does not conduct heat well. As a solution, several Class Y capacitors are connected in series.

[0004] It is an object of the present invention to provide a class Y capacitor that can operate as a filter component in high voltage applications without overheating. [Means for solving the problem]

[0005] This object is achieved by a class Y capacitor having the features of claim 1.

[0006] This invention is based on the idea that a Class Y capacitor can be operated without risk of overheating if the first leg has a larger cross-section than the second leg. The first leg can then be connected to the housing chassis or ground to dissipate heat from the capacitor. If sufficient heat can be dissipated, there is no risk of the capacitor overheating. By modifying a conventional Class Y capacitor to have two legs with different cross-sections, the risk of overheating can be avoided. Implementation of this invention is inexpensive, making this solution attractive for all applications where Class Y capacitors are subject to higher voltages, higher switching frequencies, and faster switching speeds.

[0007] According to the invention, it is possible for the first leg to have two or more leads. The use of several leads increases the surface area over which heat is dissipated. This can also improve the mechanical stability of the capacitor in position Y when placed on a printed circuit board.

[0008] According to a preferred embodiment of the present invention, the leads are preferably formed as parallel wires. Using wire-shaped leads is easy, and therefore the capacitor of the present invention can be manufactured using conventional machinery. Furthermore, such wires can be easily placed on a PCB.

[0009] Preferably, the first leg of the Class Y capacitor of the present invention is formed as a strip. Preferably, the strip has a rectangular cross section. This shape allows the first leg to have a larger cross section than the second leg, resulting in a greater amount of heat being dissipated through the strip. Such a strip can dissipate several times more heat than a conventional wire with a circular cross section.

[0010] The conductor of the class Y capacitor of the present invention may be divided into several sections, each section being connected to the first leg and the second leg. Preferably, the class Y capacitor includes three sections.

[0011] Preferably, the three parts are formed as bobbins, preferably arranged in parallel. Each bobbin may be provided with a housing, which may be made of a plastic or metal material.

[0012] The first and second conductors of the class Y capacitor of the present invention may be housed within a metal housing.

[0013] The metal housing of the Class Y capacitor of the present invention may be provided with mounting points for mounting heat dissipating components, and the mounting points may be provided with holes so that screws can be used to mount the capacitor to a support.

[0014] It is particularly preferred that the first conductor and / or the first leg be connected to a metal housing, which assists in the transfer of heat from the conductor to the housing.

[0015] Furthermore, the present invention relates to an inverter having a Class Y capacitor of the present invention, in which the first leg having a larger cross section is connected to the chassis and / or ground and the second leg is connected to an AC or DC line. The inverter of the present invention is very reliable because the Class Y capacitor does not overheat.

[0016] The invention will now be described by way of a preferred example with reference to the drawings, which are schematic and show: [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a first embodiment of a class Y capacitor of the present invention. [Figure 2] 2 is a second embodiment of a class Y capacitor of the present invention. [Figure 3] 3 is a third embodiment of a class Y capacitor of the present invention. [Figure 4] 4 is a fourth embodiment of the class Y capacitor of the present invention. [Figure 5] This is an inverter of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0018] FIG. 1 shows an exploded perspective view of a first embodiment of a Class Y capacitor 1, formed in a rectangular parallelepiped shape. Contained within the capacitor 1 are a first conductor 2 and a second conductor 3, separated by a dielectric medium and formed as a wound film. The first conductor 2 is connected to a first leg 4, and the second conductor 3 is connected to a second leg 5. Furthermore, the Class Y capacitor 1 also includes a housing 6 in the form of a rectangular case with an open side, into which the wound conductors 2 and 3 can be inserted. The housing 6 is preferably made of a metal material to further optimize thermal behavior. However, in other embodiments, the housing can be made of aluminum, steel, or a plastic material, for example.

[0019] Both legs 4, 5 are formed as wires, with the first leg 4 having a larger cross-section than the second leg 5. Class Y capacitor 1 is particularly suitable for applications where the adverse effects of electromagnetic and radio frequency interference must be prevented or minimized, such as inverters that convert direct current to alternating current. During operation, Class Y capacitor 1 heats up due to electrical losses. This heat must be dissipated to prevent the temperature of Class Y capacitor 1 from exceeding a predetermined limit. First leg 4, with its larger cross-section, is suitable for connection to the housing of an electronic device, such as an inverter housing. Second leg 5 is intended for connection to the busbars of the electronic device. Due to its larger cross-section, first leg 4 functions as a heat conductor, helping to dissipate heat from Class Y capacitor 1. This embodiment has the advantage that additional cooling, such as water cooling, is not required. Dissipation of heat from Class Y capacitor 1 through first leg 4, with its larger cross-section, is sufficient to keep the temperature below the limit.

[0020] FIG. 2 shows a second embodiment of a Class Y capacitor 7. Components identical to those of the first embodiment will not be described in detail again. According to the first embodiment, the Class Y capacitor 7 includes a wound first conductor 2 and a wound second conductor 3, and a housing 6 into which the conductors 2 and 3 are inserted. The first conductor 2 is connected to two separate first legs 8 and 9. The second conductor 3 is connected to two separate second legs 10 and 11. The first legs 8 and 9 have a larger cross-section than the second legs 10 and 11. In this embodiment, the legs 8, 9, 10, and 11 have a circular cross-section, although other shapes, such as a square or rectangular cross-section, are also possible. Because the overall cross-section of the first legs 8 and 9 is larger than that of the first embodiment, the Class Y capacitor 7 can dissipate even more heat than the Class Y capacitor 1 of the first embodiment. Furthermore, the use of four legs improves the mechanical stability of the Class Y capacitor 7 when mounted on a support such as a printed circuit board. To further improve heat transfer, the first legs 8, 9 may be connected to a metal housing of an electronic device such as an inverter.

[0021] Figure 3 shows a third embodiment of a Class Y capacitor 12 similar to the first embodiment. The Class Y capacitor 12 includes a first leg 13 and a second leg 5. The first leg 13 has a rectangular cross section and is strip-shaped. Due to its large cross section, the first leg 13 can dissipate a relatively large amount of heat. The first leg 13 has an angled end 14 with a hole 15, allowing the Class Y capacitor 12 to be fastened to a support with a screw. The first leg 13 may be connected to the chassis or inverter housing, and the second leg 5 may be connected to a busbar. In this third embodiment, the first leg 13 is internally connected to the bobbin of the Class Y capacitor 12. Alternatively, the first leg 13 may be connected to a metallic housing 6, which serves as a ground connection. In this case, a capacitor film is connected to the metal housing inside the housing 6. This configuration is thermally advantageous for the first leg 13 and the housing connection.

[0022] FIG. 4 shows a fourth embodiment of a class Y capacitor 16 having a first conductor and a second conductor divided into three sections formed as a bobbin 17 and arranged in parallel. A first leg 18 connected to the first conductor has a larger cross-section than a second leg 19 connected to the second conductor. Both legs 18, 19 have angled ends 20, 21, respectively, with holes 22. The class Y capacitor 16 may be housed in a housing (not shown). Due to the asymmetrical connection, the thermal interface of the class Y capacitor 16 is more effective on the side of the leg 18 with the larger cross-section than on the other side of the leg 19.

[0023] 5 is a schematic diagram of an inverter 23 connected to a battery 24 and a motor 25. Direct current from the battery 24 is converted to alternating current by the inverter 23. The inverter includes a high-voltage DC bus filter, which illustratively comprises an inductor 26, a class Y capacitor 27, and a power semiconductor device 28. The alternating current is used to drive the motor 25. [Explanation of symbols]

[0024] 1 Class Y Capacitor 2 First conductor 3 Second Conductor 4 First Leg 5 Second leg 6. Housing 7 Class Y Capacitors 8 First Leg 9 First Leg 10 Second leg 11 Second leg 12 Class Y Capacitors 13 First Leg 14 End 15 holes 16 Class Y Capacitors 17 Bobbin 18 First Leg 19 First Leg 20 End 21 End 22 holes 23 Inverter 24 Battery 25 motor 26 Inductor 27 Class Y Capacitors 28 Power Semiconductor Devices

Claims

1. A class Y capacitor (1, 7, 12, 16, 27) that can be connected between a line and ground, comprising first and second conductors (2, 3) separated by a dielectric medium; The first conductor (2) is connected to the first legs (4, 8, 9, 13, 18); The second conductor (3) is connected to the second leg (5, 10, 11, 19); A class Y capacitor, characterized in that said first legs (4, 8, 9, 13, 18) have a larger cross section than said second legs (5, 10, 11, 19).

2. 2. The class Y capacitor of claim 1, wherein the first leg (8, 9, 18) comprises two or more leads.

3. 3. A class Y capacitor as claimed in claim 2, wherein the leads are formed as wires preferably arranged in parallel.

4. 4. A class Y capacitor according to claim 1, wherein the first legs (13, 18) are formed as strips.

5. 5. A class Y capacitor according to claim 4, wherein the strip (13) has a rectangular cross section.

6. the conductors (2, 3) are divided into several parts, preferably three parts, 6. A class Y capacitor according to any one of claims 1 to 5, wherein each section is connected to the first leg (18) and the second leg (19).

7. 7. A class Y capacitor according to claim 6, wherein the three parts are formed as bobbins (17), preferably arranged in parallel.

8. 8. A class Y capacitor according to any one of claims 1 to 7, wherein the conductors (2, 3) are housed in a metal housing (6).

9. 9. A class Y capacitor according to claim 8, wherein the metal housing (6) is provided with mounting points for mounting heat dissipation components.

10. 10. A class Y capacitor according to claim 8 or 9, wherein the first conductor (2) and / or the first leg (4, 8, 9, 13, 18) are connected to the metal housing (6).

11. A class Y capacitor (27) according to any one of claims 1 to 10, connected to a chassis and / or ground by the first leg having the larger cross section; An inverter (23) connected by said second leg to an AC or DC line.

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