Electrical equipment

Abstract

To prevent condensation on the walls, etc. of a sealed space and to prevent damage to an electrical component due to atmospheric pressure in electrical equipment in which the electrical component such as an electrolytic capacitor is arranged in the sealed space.SOLUTION: The electrical equipment includes an electrical component, an electrical component support and an outer frame. An internal space is formed between the electrical component support and the outer frame. The electrical component is installed in the inner space. The inner space is filled with a gas having a water vapor pressure of 0.60 kPa or less.SELECTED DRAWING: Figure 1

Description

Technical Field

[0005]

[0001] The present disclosure relates to electrical equipment.

Background Art

[0002] Towards the realization of a zero-carbon society, CO2 emission regulations are strongly demanded in each country, and as an alternative to engines using fossil fuels, electrification of the power system is actively promoted. In all engine-driven mobility products, the application of power electronics equipment is being considered, and an improvement in its output density is required. Along with this, power electronics equipment is required to be applicable to any climate in the world. In aircraft, environmental resistance capable of coping with rapid altitude changes is essential. At the same time, improvements in cooling performance, higher voltage, weight reduction, etc. are required, and technical development for this is underway.

[0003] Patent Document 1 discloses an air conditioner equipped with an inverter device for driving an electric compressor. As a dew condensation prevention structure inside the case of the inverter device, an inert gas is filled in the case accommodating the power element and the control circuit for controlling the same. In Patent Document 1, it is described that the inert gas is filled at normal temperature and at a pressure slightly higher than atmospheric pressure.

[0004] Patent Document 2 discloses a power conversion device for an aircraft, which includes a sealed housing including a gas inlet valve and a gas outlet valve, a power semiconductor module disposed in the internal space of the sealed housing, and a dry gas filling the internal space of the sealed housing. Further, Patent Document 2 discloses injecting a dry gas from the ambient pressure (for example, atmospheric pressure) outside the sealed housing to set the internal space of the sealed housing to a set pressure.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] Patent documents 1 and 2 disclose a method for raising the air pressure inside a container containing electrical components to a level higher than atmospheric pressure. However, some types of electrical components may be damaged when the air pressure is increased.

[0007] This disclosure aims to prevent condensation from occurring on the walls of a sealed space and damage to electrical components due to air pressure in electrical equipment in which electrical components such as electrolytic capacitors are placed in a sealed space. [Means for solving the problem]

[0008] The electrical equipment of this disclosure comprises an electrical component, an electrical component support, and an outer frame, wherein an internal space is formed between the electrical component support and the outer frame, the electrical component is installed in the internal space, and the internal space is filled with a gas having a water vapor pressure of 0.60 kPa or less. [Effects of the Invention]

[0009] According to this disclosure, in electrical equipment in which electrical components such as electrolytic capacitors are arranged in a sealed space, it is possible to prevent condensation from occurring on the walls of the sealed space and to prevent damage to the electrical components due to air pressure. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic cross-sectional view showing the electrical equipment of Example 1. [Figure 2] This is a schematic cross-sectional view showing the electrical equipment of Example 2. [Figure 3] This is a schematic cross-sectional view showing the electrical equipment of Example 3. [Figure 4] This is a schematic cross-sectional view showing the electrical equipment of Example 4. [Figure 5]This is a schematic cross-sectional view showing the electrical equipment of Example 5. [Modes for carrying out the invention]

[0011] The embodiments relating to this disclosure will be described in detail below with reference to the drawings.

[0012] In this specification, electrical and electronic equipment that functions as an energy source is collectively referred to as "electrical equipment." Electrical equipment also includes power converters. [Examples]

[0013] Figure 1 is a schematic cross-sectional view showing the electrical equipment of Example 1.

[0014] The electrical device shown in this figure is a power converter with a liquid cooling mechanism. The power converter comprises a switching element 1, an electrolytic capacitor 60, a substrate 2, a substrate support 21, a heat conductive member 22, and an outer frame 90.

[0015] A liquid channel 8 is provided in the substrate support section 21. The substrate 2 and the heat conductive member 22 are installed in the substrate support section 21. The switching element 1 is positioned in contact with the heat conductive member 22. The electrolytic capacitor 60 is positioned on the substrate 2.

[0016] The outer frame 90 is fixed to the substrate support portion 21 so as to cover the switching element 1, the electrolytic capacitor 60, the substrate 2, and the heat conductive member 22. Thereby, an internal space 92 is formed between the substrate support portion 21 and the outer frame 90. The internal space 92 is completely sealed so that there is no air in and out with the outside. The switching element 1, the electrolytic capacitor 60, the substrate 2, and the heat conductive member 22 are configured not to contact the outer frame 90. A gas substantially free of water vapor such as dry air is enclosed in the internal space 92. Thereby, condensation does not occur on the inner wall surface of the outer frame 90. The water vapor pressure of the gas enclosed in the internal space 92 is preferably 0.60 kPa or less, more preferably 0.080 kPa or less, and particularly preferably 0.0020 kPa or less. Here, dry air has the same composition as normal atmosphere (including about 78% by volume of nitrogen and about 21% by volume of oxygen as main components).

[0017] The switching element 1 includes a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) or a power module. The substrate support portion 21 is made of metal. In this specification, components that function by being energized like the switching element 1 are collectively referred to as "electrical components". Electrical components include capacitors, printed circuit boards (PCBs), etc.

[0018] The outer frame 90 is made of metal such as an aluminum alloy or stainless steel, and bears the strength as a cover of the switching element 1. The thickness of the outer frame 90 is preferably about 2 to 3 mm depending on the material.

[0019] Also, by making the outer frame 90 of metal, even if lightning strikes, it is difficult for noise current to occur inside the power conversion device, and malfunction can be made difficult to occur.

[0020] The contact area between the substrate support portion 21 and the heat conduction member 22, and the contact area between the switching element 1 and the heat conduction member 22 are preferably made wide enough so that the heat generated in the switching element 1 can be sufficiently removed. Also, the liquid flow path 8 of the substrate support portion 21 is preferably arranged so that the liquid flowing through the liquid flow path 8 can sufficiently remove heat from the heat conduction member 22. Examples of the liquid flowing through the liquid flow path 8 include water, mineral oil, fluorocarbon-based coolants, vegetable oil, and the like. In this specification, although the cooling of the power conversion device and the like by the liquid flowing through the liquid flow path 8 is described, the cooling mechanism of the electric device according to the present disclosure is not limited to this, and may be by a gas such as air, by a refrigerant accompanied by a phase change, or the like. Specifically, it may be by forced air cooling or using a heat pipe.

[0021] The electrolytic capacitor 60 is used for smoothing and filtering in the power conversion device. In addition to such a capacitor, ceramic capacitors, film capacitors, hybrid capacitors, and the like are also applicable. Capacitors other than those exemplified here may be applied, and the type is not limited.

[0022] In the case of the electrolytic capacitor 60, a valve may be provided in the electrolytic capacitor 60 in order to prevent damage due to an increase in atmospheric pressure. In this case, when the pressure of the gas in the internal space 92 of the sealed power conversion device rises due to a temperature increase during operation or the like, the operation of the valve of the electrolytic capacitor 60 may be hindered. Therefore, in a state where the power conversion device is not energized, in other words, in a state where there is no heat generation in the power conversion device and the temperature is not high, it is desirable to finely adjust the atmospheric pressure in the internal space 92 to less than the atmospheric pressure. That is, when the power conversion device is not operating, it is desirable to make the initial pressure in the internal space 92 slightly negative.

[0023] Regarding electrical components other than the electrolytic capacitor 60, by making the internal space 92 negative pressure, the pressure increase during operation can be offset, and damage to each electrical component can be prevented.

[0024] The substrate support portion 21 having the liquid channel 8 is preferably at ground potential. The substrate support portion 21 is preferably made of an aluminum alloy, stainless steel, copper alloy, or other metal.

[0025] In low-pressure environments, the partial discharge initiation voltage is significantly lower than at atmospheric pressure. Therefore, a solid or liquid with a partial discharge initiation voltage approximately 10 times higher than that of air must be applied to the surface to which the voltage is applied and the surface to which it is grounded.

[0026] When there is concern about the initiation of partial discharge due to high voltage, high electric field stress, etc., it is desirable to cover areas with high electrical stress, such as the periphery of switching element 1, with a solid insulating material such as silicone. This makes it less likely for partial discharge to occur under low pressure conditions. Other suitable solid insulating materials include polyphenylene sulfide resin (PPS), epoxy resin, and unsaturated polyester.

[0027] The gas sealed in the internal space 92 may be dry air, nitrogen, argon, carbon dioxide, nitrogen dioxide, or other gases. Ideally, the gas should not liquefy even at -70°C. Alternatively, these gases may be mixed and sealed together.

[0028] Furthermore, the gas sealed in the internal space 92 may be dry air to which oxygen has been added to increase the oxygen concentration above that of the atmosphere (oxygen concentration 21 vol%). Increasing the oxygen concentration increases the electron adhesion of the sealed gas, making it easier to suppress discharge and improving insulation. In addition to oxygen, other gases that increase electron adhesion may be carbon dioxide, sulfur hexafluoride, carbon monoxide, etc. In addition to the aforementioned sulfur hexafluoride, halogen-containing gases may also be mixed. Known halogen-containing gases containing fluorine, chlorine, iodine, etc. include fluoride gases such as BF3 and CF4, as well as chloride gas and fluorocarbon gases.

[0029] Furthermore, the internal space 92 may be depressurized to a vacuum. In this case, a higher degree of vacuum is desirable, specifically, 1 Pa or less is desirable, and 0.1 Pa or less is even more desirable. By creating a vacuum in the internal space 92, the water vapor pressure is also reduced, which can prevent condensation, etc. In addition, corrosion caused by condensation and malfunctions due to lightning surges can be prevented. [Examples]

[0030] In this embodiment, only the configurations that differ from those in Embodiment 1 will be described.

[0031] Figure 2 is a schematic cross-sectional view showing the electrical equipment of Example 2.

[0032] In this figure, a low-pressure chamber 100 is provided between the substrate support 21 and the outer frame 90, in addition to the internal space 92. The internal space 92 and the low-pressure chamber 100 are separated by a partition plate 101. A vent filter 99 is provided on the partition plate 101.

[0033] The electrical components are installed in the internal space 92. The low-pressure chamber 100 has a lower pressure than the internal space 92. With this configuration, if the pressure in the internal space 92 increases due to heat generated by the electrical components, the vent filter 99 opens, allowing the gas in the internal space 92 to flow out into the low-pressure chamber 100. In this case, in the initial state, it is possible to raise the pressure in the internal space 92 above atmospheric pressure (1 atm). [Examples]

[0034] In this embodiment, only the configurations that differ from those in Embodiment 1 will be described.

[0035] Figure 3 is a schematic cross-sectional view showing the electrical equipment of Example 3.

[0036] In this figure, the switching element 1 is electrically connected to the outside by a cable 111. The cable 111 is a wire with a protective coating. The cable outlet for the cable 111, provided on the outer frame 90, is sealed with silicone FIPG 112 or the like to ensure airtightness of the internal space 92. Here, FIPG is an abbreviation for Formed In Place Gasket. [Examples]

[0037] In this embodiment, only the configurations that differ from those in Embodiment 3 will be described.

[0038] Figure 4 is a schematic cross-sectional view showing the electrical equipment of Example 4.

[0039] In this diagram, the switching element 1 is electrically connected to the outside by a busbar 115 connected to it. A cable may be used instead of the busbar 115. The cable is a wire with a protective covering.

[0040] The connection point for the busbar 115 provided on the outer frame 90 is a BNC connector 116 (Bayonet Neill-Concelman connector). This ensures airtightness of the internal space 92 and also facilitates connection work. [Examples]

[0041] In this embodiment, only the configurations that differ from those in Embodiment 1 will be described.

[0042] Figure 5 is a schematic cross-sectional view showing the electrical equipment of Example 5.

[0043] In this figure, instead of the outer frame 90 (made of metal) in Figure 1, a frame is used in which the outer wall surface of a flame-retardant resin frame 130 is covered with a metal coating 131. This frame is also called an "outer frame." The metal coating 131 is preferably made of aluminum, iron, nickel, etc. The metal coating 131 may also be applied to the inner wall surface of the flame-retardant resin frame 130. This configuration can prevent ignition during lightning strikes and the inflow of noise. It can also reduce the weight of electrical equipment.

[0044] Suitable materials for the flame-retardant resin frame 130 include, for example, foamed resins such as polyurethane, polystyrene, polyethylene, polypropylene, and silicone. Vacuum insulation materials with glass wool or silica powder as core materials are also desirable. However, the materials for the flame-retardant resin frame 130 are not limited to these.

[0045] Alternatively, a metal frame may be used instead of the flame-retardant resin frame 130.

[0046] In the above embodiment, the electrical device has a substrate 2, a substrate support portion 21, and a heat conductive member 22. However, the electrical device according to this disclosure does not necessarily have to have these parts, and instead of the substrate support portion 21, it may have a member that supports electrical components. Furthermore, an internal space may be formed between the member and the outer frame 90. In this specification, the substrate support portion 21 and the member are collectively referred to as the "electrical component support portion."

[0047] Furthermore, the electrical equipment described in this disclosure is also applicable to all forms of mobility, including aircraft, transportation equipment, and construction machinery.

[0048] The following describes preferred embodiments of the electrical equipment related to this disclosure.

[0049] Electrical components include electrolytic capacitors.

[0050] The air pressure inside the space is set to be lower than atmospheric pressure.

[0051] The gas in the internal space is dry air, nitrogen, argon, carbon dioxide, or nitrogen dioxide, or a mixture of two or more of these.

[0052] The internal space is in a vacuum state.

[0053] The outer frame is made up of one or more of the following materials: polyurethane, polystyrene, polyethylene, polypropylene, and silicone, and is covered with a metal coating.

[0054] The outer frame includes a vacuum insulation material containing one or more of either glass wool or silica powder as a core material.

[0055] The oxygen concentration of the gas in the internal space is higher than 21% by volume.

[0056] The gas in the internal space contains one or more of the following: carbon dioxide, sulfur hexafluoride, carbon monoxide, and halogen-containing gases.

[0057] Between the electrical component support section and the outer frame, a low-pressure chamber adjacent to the internal space is provided. The low-pressure chamber is set to a lower atmospheric pressure than the internal space, and a vent filter is provided between the internal space and the low-pressure chamber.

[0058] The electrical components are electrically connected to the outside by cables, and the cable outlets located on the outer frame are sealed with silicone FIPG.

[0059] Electrical components are electrically connected to the outside by cables or busbars, and BNC connectors are provided at the cable outlets or busbar connection points located on the outer frame. [Explanation of symbols]

[0060] 1: Switching element, 2: Substrate, 8: Liquid flow path, 21: Substrate support, 22: Thermal conductive material, 60: Electrolytic capacitor, 90: Outer frame, 92: Internal space, 99: Vent filter, 100: Low-pressure chamber, 101: Partition plate, 111: Cable, 112: Silicone FIPG, 115: Busbar, 116: BNC connector, 130: Flame-retardant resin frame, 131: Metal coating.

Claims

1. Electrical components and, Electrical component support section, Equipped with an outer frame, An internal space is formed between the electrical component support portion and the outer frame. The aforementioned electrical components are installed in the internal space, The aforementioned internal space is filled with a gas having a water vapor pressure of 0.60 kPa or less. An electrical device wherein the outer frame comprises one or more of polyurethane, polystyrene, polyethylene, polypropylene, and silicone, and is covered with a metal coating.

2. The electrical device according to claim 1, wherein the aforementioned electrical component includes an electrolytic capacitor.

3. The electrical apparatus according to claim 1, wherein the air pressure in the internal space is set to less than atmospheric pressure.

4. The electrical equipment according to claim 1, wherein the gas is dry air, nitrogen, argon, carbon dioxide, or nitrogen dioxide, or a mixture of two or more of these.

5. The electrical apparatus according to claim 1, wherein the internal space is in a vacuum state.

6. The electrical equipment according to claim 1, wherein the outer frame includes a vacuum insulation material containing one or more of glass wool and silica powder as a core material.

7. The electrical apparatus according to claim 1, wherein the oxygen concentration of the gas is higher than 21% by volume.

8. The electrical equipment according to claim 1, wherein the gas contains one or more of carbon dioxide, sulfur hexafluoride, carbon monoxide, and halogen-containing gases.

9. Between the electrical component support section and the outer frame, a low-voltage chamber adjacent to the internal space is provided. The aforementioned low-pressure chamber is set to a lower pressure than the internal space, The electrical equipment according to claim 1, wherein a vent filter is provided between the internal space and the low-pressure chamber.

10. The aforementioned electrical component is electrically connected to the outside by a cable. The electrical equipment according to claim 1, wherein the cable outlet provided in the outer frame is sealed with silicone FIPG.

11. The aforementioned electrical components are electrically connected to the outside by cables or busbars. The electrical equipment according to claim 1, wherein a BNC connector is provided at the cable outlet or busbar connection portion provided on the outer frame.

12. An electrical device according to claim 1, which is a power conversion device.

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