JP2022136855A - Power conversion unit and power conversion device - Google Patents

Abstract

To provide a power conversion unit with high reliability of an operation even at temperature and air pressure deviated from ordinary temperature and ordinary pressure, and whose weight can also be reduced depending on selection of a material, and a power conversion device with the same.SOLUTION: A power conversion unit 1 comprises: a cooling unit 5; an input side power conversion unit 3 arranged on one side of the cooling unit 5; an output side power conversion unit 4 arranged to face the input power conversion unit 3 with the cooling unit 5 therebetween; and a housing 2 which covers the cooling unit 5, the input side power conversion unit 3 and the output side power conversion unit 4, in which the input side power conversion unit 3 and the output side power conversion unit 4 have switching elements 11 and circuit boards 10, and the housing 2 is porous. A power conversion device comprises: a plurality of power conversion units 1; and a frame which accommodates the power conversion units 1 so as to be supported, and the plurality of power conversion units 1 supported in the frame are electrically connected in series or in parallel with one another.SELECTED DRAWING: Figure 3

Description

The present invention relates to a power conversion unit and a power conversion device.

Hybrid vehicles and electric vehicles are becoming popular due to the recent heightened awareness of the problem of global warming and the reduction of _CO2 emissions. Power sources for vehicles and the like will replace engines that require fossil fuels with motors due to electrification. Motors as a power source are expected to contribute to curbing global warming because they emit less _CO2 when fossil fuels are not used.

When a motor is used as a power source, a power converter is required to control the rotation of the motor. Power converters are indispensable for improving the operating efficiency of motors in hybrid and electric vehicles, as well as other products. In general, a power conversion device is provided as an auxiliary device to a main device such as a motor that uses power and a storage battery that stores power.

At present, with the spread of motors, storage batteries, etc. as power sources, there is a demand for miniaturization and weight reduction of the entire power system including the main engine. Therefore, it is desired to reduce the size and weight of the power converter as well. In addition, as motors, storage batteries, etc. become popular, it is expected that usage environments for motors, storage batteries, etc. will expand. Therefore, power converters are desired to have performance corresponding to various usage environments.

For example, the temperature drops by about 0.6°C for every 100m increase in altitude. At low temperatures, dew condensation is more likely to occur, so short-circuits, deterioration and breakage of circuit elements, deterioration and deterioration of materials, and the like are more likely to occur. In addition, in high-altitude operating environments, not only the temperature but also the atmospheric pressure is low, so different performance is required than at low altitudes. It is known that discharge is more likely to occur under low atmospheric pressure according to Paschen's law.

Power converters are desired to be designed with high reliability so that desired operation can be maintained for a long period of time even in environments where low temperature deterioration, heat deterioration, thermal stress, short circuit, dielectric breakdown, etc. are likely to occur. . If the design is highly resistant to temperature and atmospheric pressure deviating from normal temperature and atmospheric pressure, and temperature and atmospheric pressure changes, equipment with the same specifications can be used in various environments, improving the mass production and cost efficiency of equipment. There is expected.

Patent Documents 1 to 3 describe techniques related to miniaturization of power converters.

JP 2020-178406 A (paragraph 0006, FIG. 2, etc.) JP 2020-077763 A (paragraph 0010, FIG. 2, etc.) JP 2014-050113 A (paragraph 0010, FIG. 6, etc.)

It is desired to reduce the weight and size of power converters. In addition, there is a demand for a structure that is highly resistant to temperature and atmospheric pressure that deviate from normal temperature and atmospheric pressure, and to temperature and atmospheric pressure changes. From the viewpoint of mass productivity and cost efficiency of the apparatus, it is desired that the apparatus of the same specification essentially have such performance.

The techniques described in Patent Documents 1 to 3 improve the structure related to heat dissipation in order to cool the heat-generating parts built into the device. However, although the devices described in Patent Documents 1 to 3 have improved heat dissipation from the inside to the outside, they have structures that sufficiently ensure reliability against the effects of the external environment where the devices are placed. It cannot be said that it is. In addition, there is room for significant improvement in terms of weight reduction of the device.

Therefore, the present invention provides a power conversion unit that has high operational reliability even at temperatures and pressures that deviate from normal temperature and pressure, and that can be made lighter depending on the selection of materials, and a power conversion device including the same. intended to

In order to solve the above problems, the power conversion unit according to the present invention includes: a cooling unit through which a cooling medium flows; an input-side power conversion unit arranged on one side of the cooling unit; an output-side power conversion unit disposed facing each other across the cooling unit; and a housing covering the cooling unit, the input-side power conversion unit, and the output-side power conversion unit, wherein the input-side power The conversion section and the output-side power conversion section each have a switching element and a circuit board, and the casing is porous.

Further, a power conversion apparatus according to the present invention includes the plurality of power conversion units and a frame that accommodates and supports the power conversion units, wherein the plurality of power conversion units supported in the frame are , are electrically connected in series or in parallel with each other.

According to the present invention, there is provided a power conversion unit that is highly reliable in operation even at temperatures and pressures that deviate from normal temperature and pressure, and that can be made lighter depending on the selection of materials, and a power converter including the same. can do.

It is the perspective view which looked at the power conversion unit which concerns on embodiment of this invention from the front side. It is the perspective view which looked at the power conversion unit which concerns on embodiment of this invention from the back surface side. 1 is a cross-sectional view of a power conversion unit according to an embodiment of the invention; FIG. It is a figure which shows an example of the circuit incorporated in a power inverter unit. FIG. 2 is a perspective view showing an example of a divided structure of a housing when the housing is viewed from the front side. FIG. 3 is a perspective view showing an example of a divided structure of a housing when the housing is viewed from the rear side; FIG. 4 is a top view showing an example of a joint structure of a housing, in which a main part of the housing provided in the split structure is enlarged. FIG. 4 is a cross-sectional view showing an example of a joining structure of a housing, in which a main part of the housing provided in the split structure is enlarged. It is a cross-sectional view of the power conversion unit which concerns on the modification of this invention. FIG. 2 is a perspective view showing an example of a divided structure of a housing when the housing is viewed from the front side. FIG. 3 is a perspective view showing an example of a divided structure of a housing when the housing is viewed from the rear side; FIG. 4 is a top view showing an example of a joint structure of a housing, in which a main part of the housing provided in the split structure is enlarged. FIG. 4 is a cross-sectional view showing an example of a joining structure of a housing, in which a main part of the housing provided in the split structure is enlarged. FIG. 4 is a perspective view showing an example of the rib structure of the housing when the housing is viewed from the rear side; BRIEF DESCRIPTION OF THE DRAWINGS It is the perspective view which looked at the power converter device which concerns on embodiment of this invention from the front side.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A power conversion unit according to an embodiment of the present invention and a power converter including the same will be described below with reference to the drawings. In addition, in each of the following figures, the same reference numerals are given to the common configurations, and redundant explanations are omitted.

FIG. 1 is a front perspective view of a power conversion unit according to an embodiment of the present invention. FIG. 2 is a rear perspective view of the power conversion unit according to the embodiment of the present invention. FIG. 3 is a cross-sectional view of a power conversion unit according to an embodiment of the invention. FIG. 3 corresponds to a cross-sectional view taken along the two-dot chain line in FIG.
As shown in FIGS. 1 to 3, the power conversion unit 1 according to the present embodiment includes a housing 2 that forms an outer shell, an input side power conversion section 3 that converts input power, and a power converter that converts the power. It is provided with an output-side power converter 4 that outputs power and a cooling unit 5 that cools heat-generating components. The power conversion unit 1 is a device that performs AC/DC conversion as an example of power conversion.

The housing 2 accommodates the input side power conversion section 3 , the output side power conversion section 4 and the cooling section 5 . The housing 2 covers all or part of these built-in components except for terminals and the like. In the power conversion unit 1 according to the present embodiment, as described later, the housing 2 is made of a resin having a high electrical resistivity, and the pores in the resin matrix are mainly closed pores (independent cells). and

As shown in FIG. 1, the front side of the housing 2 is provided with through holes 21a and 21b for cooling pipes. Cooling pipes 51 and 52 are led out from the inside of the housing 2 to the outside through the through holes 21a and 21b. In FIG. 1, two through holes 21a and 21b are provided for the cooling pipes corresponding to the two cooling pipes 51 and 52, respectively.

The through-holes 21a and 21b for cooling pipes are horizontally arranged near the center of the front surface of the housing 2 in the vertical direction. The tip sides of the cooling pipes 51 and 52 are exposed to the outside of the housing 2 . The cooling pipes 51 and 52 form pipelines through which a cooling medium flows, and can be connected to a cooling unit via pipes, tubes, or the like. One of the cooling pipes 51 and 52 is on the inlet side and the other is on the outlet side.

The cooling unit is a device that causes a cooling medium to flow through the power conversion unit 1, and is connected to the power conversion unit 1 while the power conversion unit 1 is in operation, on standby, or the like. The cooling unit supplies a low-temperature cooling medium to the power conversion unit 1 while the power conversion unit 1 is operating, waiting, or the like, and recovers the high-temperature cooling medium that has received heat from the power conversion unit 1 .

As shown in FIG. 2, through holes 22a, 22b, 23a, and 23b for terminals are provided on the rear side of the housing 2. As shown in FIG. Input terminals 31 and 32 and output terminals 41 and 42 are led out from the inside of the housing 2 to the outside through the through holes 22a, 22b, 23a and 23b. In FIG. 2, two through-holes for terminals, a through-hole 22a on the left side and a through-hole 22b on the right side, are provided corresponding to the two input terminals 31 and 32, respectively. Two through holes 23a and 23b are provided corresponding to the two output terminals 41 and 42, respectively.

The through holes 22a and 22b through which the input terminals 31 and 32 are drawn out are aligned substantially horizontally above the rear surface of the housing 2 in the vertical direction and on one side in the horizontal direction. The through holes 23a and 23b through which the output terminals 41 and 42 are drawn out are arranged substantially horizontally on the lower side of the rear surface of the housing 2 in the vertical direction and on the opposite side in the horizontal direction. The tip sides of the terminals 31 , 32 , 41 , 42 are exposed to the outside of the housing 2 . The terminals 31, 32, 41, and 42 are connectable to a main machine such as a power source, a motor, and a storage battery via wiring.

As materials for the terminals 31, 32, 41, and 42, materials with low electrical resistivity, such as metals such as copper, silver, and aluminum, and alloys thereof can be used. Also, when the unit is used in an environment where corrosion resistance is required, nickel, nickel alloy, stainless steel, etc. can be used. The surfaces of the terminals may be plated to prevent corrosion. As the plating treatment, gold plating, silver plating, tin plating, or the like can be used.

In the power conversion unit 1 that performs AC/DC conversion, when AC power is input to the input terminals 31 and 32, the waveform is converted by the input side power conversion section 3 and the output side power conversion section 4 built in the housing 2. , output terminals 41 and 42 output DC power. Such a power conversion unit 1 can be used, for example, as an accessory such as a motor or a storage battery.

The housing 2 is made of a resin having a high electrical resistivity, and is porous in that the pores in the resin matrix are mainly closed pores (independent cells). The porous casing 2 can be formed, for example, as a rigid foam-like foam made by foaming a resin, or a molded product in which pores are dispersed in a resin matrix. The housing 2 mainly has closed pores in order to reduce the influence of temperature and atmospheric pressure on the inside, but may partially have open pores.

Methods for forming the porous casing 2 include a method of generating gas in the raw material resin by a gas generation reaction or a thermal decomposition reaction, a method of injecting gas into the raw resin to disperse the pores, and a method of stirring the raw resin.・Method of dispersing pores by shearing, method of dispersing porogen in raw material resin and separating from substantially closed pores after curing, method of dispersing hollow-structured filler in raw resin, high bulk density in raw resin An appropriate method can be used, such as a method of dispersing the filler and stirring and shearing to disperse the pores.

Examples of materials for the housing 2 include epoxy resin, polyurethane (PU), polyethylene (PE), polypropylene (PP), polystyrene (PS), polyethylene terephthalate (PET), ethylene vinyl acetate copolymer (EVA), and polycarbonate. (PC), modified polyphenylene ether (mPPE), polyamide (PA), polyimide (PI), polyamideimide (PAI), and the like can be used. By using a resin as the porous material, the weight can be reduced.

For example, PS for cost reduction, PP for lightness and strength, PE for molding precision, PC for impact resistance, PA, PI for heat resistance, PAI or the like can be used. As the material of the housing 2, one type of resin may be used, a polymer alloy of a plurality of resins may be used, or a modified resin into which a reactive group or the like is introduced may be used.

All of these resins can basically be made porous by appropriately selecting a foaming method or a method of dispersing air bubbles/pores. A preferred method for forming the porous housing 2 is a method of foaming a thermoplastic resin containing a foaming agent in a molten state, or a method of dispersing the foaming agent in a monomer such as a thermosetting resin to initiate a curing reaction. There is a method of foaming during the process, and a method of using a hollow filler instead of these foaming agents. According to these methods, expansion ratio, porosity, density, etc. can be relatively stably controlled.

Examples of hollow structure fillers include glass balloons, silica balloons, etc., hollow structure inorganic fillers formed of alumina, zirconia, carbon, fly ash, shirasu, pearlite, etc., crosslinked acrylic resins, and crosslinked styrene-acrylic resins. An organic filler or the like having a hollow structure formed by, for example, can be used. Examples of high bulk density fillers include flaky, porous, and fibrous fillers.

Conventionally, the casing of a general power conversion device is formed as a non-porous bulk using resin, metal, ceramics, or the like. A bulk housing has excellent heat dissipation from the inside to the outside if the material has high thermal conductivity. Moreover, appropriate electrical insulation can be obtained according to the electrical resistivity of the material. In addition, mechanical strength and airtightness can be easily ensured.

However, if the thermal conductivity of the material is high, there is a problem that the temperature and pressure inside the housing are affected by the temperature and pressure of the external environment where the device is placed. If the power conversion equipment is exposed to temperature and atmospheric pressure that deviate from normal temperature and atmospheric pressure, or changes in temperature and atmospheric pressure, the operation and performance of the internal components of the housing will deteriorate, and the properties of the internal components will deteriorate. occur. In addition, the bulk housing may be heavy depending on the material, which is disadvantageous in terms of weight reduction.

On the other hand, in the power conversion unit 1 according to the present embodiment, the housing 2 is made porous in which the pores in the resin matrix are mainly closed pores (independent cells). High resistance to temperature and pressure that deviate from the normal temperature and pressure of the external environment where the unit is placed, and to temperature and pressure changes . Since the internal environment inside the housing is less likely to be affected by the temperature and atmospheric pressure of the external environment, the internal environment can easily be kept normal with respect to the external environment in which the device is placed.

Therefore, according to the power conversion unit 1, low-temperature deterioration, heat deterioration, thermal stress caused by the external environment, short circuit, dielectric breakdown, etc. due to discharge under low pressure can be made less likely to occur. It is possible to maintain the operation and performance of the built-in components of the housing and the properties of the materials of the built-in components over a long period of time. In addition, since the density of the housing is lower than when bulk resin or the like is used, the weight of the unit can be reduced.

As shown in FIG. 3, the input-side power converter 3 and the output-side power converter 4 each include a circuit board 10, a switching element 11 mounted on the circuit board 10, a resonance capacitor 15 (see FIG. 4), It is composed of circuit elements such as a smoothing capacitor 16 (see FIG. 4), a heat radiation member 12, and the like. The circuit elements are electrically connected to each other via wiring to form a predetermined circuit between the input terminals 31 and 32 and the output terminals 41 and 42 .

Base ends of the input terminals 31 and 32 are electrically connected to the circuit board 10 of the input-side power converter 3 . Base end sides of the output terminals 41 and 42 are electrically connected to the circuit board 10 of the output-side power converter 4 . That is, the input terminals 31, 32 and the output terminals 41, 42 are electrically connected to circuit elements on the circuit board 10, respectively.

In the circuit elements, the surfaces of the terminals, bonding wires, etc. exposed inside the housing 2 are insulated. The insulation treatment is performed using a coating material capable of forming a film exhibiting electrical insulation, moisture resistance, dust resistance, and the like. The use of a coating material suppresses discharge between terminals, between wires, etc., so that the operation stability of the unit can be improved and failures can be reduced.

As the coating material, it is preferable to use a self-adhesive elastomer rather than a non-adhesive gel. A non-adhesive gel may crack, burst, bubble, or the like in a low-temperature environment or a low-pressure environment, which may cause partial discharge and dielectric breakdown. In addition, since the enclosed air bubbles expand in a low-pressure environment, they are easily peeled off. On the other hand, self-adhesive elastomers such as cured liquid rubber form a film that is difficult to peel off and cause partial discharge even in low-temperature or low-pressure environments. Moisture resistance, dust resistance, etc. can be ensured.

As the coating material, a material having fluidity in an uncured state at room temperature is preferable, and silicone containing organopolysiloxane as a main component is preferable. As the coating material, either an addition reaction type, a condensation reaction type, or the like can be used, but from the viewpoint of avoiding generation of air bubbles accompanying the curing reaction, it is preferable to use the addition reaction type.

Specific examples of coating materials include SYLGARD184, SH850, SE1816CV, SE1817CVM (manufactured by Dow Corning Toray Co., Ltd.) and KE-1204, KE-1282, KE-109E, KE-1846, KE-1886 (manufactured by Shin-Etsu Silicone Co., Ltd.). etc.

As shown in FIG. 3 , the input-side power conversion unit 3 and the output-side power conversion unit 4 are arranged inside the housing 2 to face each other with the cooling unit 5 interposed therebetween. The input-side power conversion unit 3 is arranged on one side of the cooling unit 5 with the cooling unit 5 interposed therebetween. The output-side power conversion unit 4 is arranged on the other side of the cooling unit 5 with the cooling unit 5 interposed therebetween. Such an arrangement facilitates ensuring electrical insulation between the power conversion units and heat dissipation from each power conversion unit to the cooling unit 5 .

The input-side power conversion unit 3, the output-side power conversion unit 4, and the cooling unit 5, which are built-in components of the housing 2, are arranged so that, for example, the circuit boards 10 are oriented in the horizontal direction and stacked vertically on each other. can be done. With such an arrangement, the pressure on the housing 2 due to the load of the internal objects is reduced, so partial compression, breakage, etc. of the porous housing 2 can be reduced.

A circuit element such as the switching element 11 is a heat-generating component that generates Joule heat due to its own resistance during operation of the unit. Heat generated in a circuit causes thermal deterioration, thermal stress, etc. in circuit elements and materials, leading to malfunction and aged deterioration. Therefore, the heat-generating parts are cooled by the cooling unit 5, and the heat is removed by the cooling unit 5 during operation of the unit, standby, and the like.

The heat dissipation member 12 is made of a material with high thermal conductivity. The heat dissipation member 12 thermally connects circuit elements such as the switching element 11 and the cooling path forming member 53 in each of the input power converter 3 and the output power converter 4 . The heat dissipation member 12 can be provided as a plate-shaped heat dissipation plate or the like. The heat dissipation member 12 can be arranged so that one surface is in surface contact with the surface of the circuit element such as the switching element 11 and the other surface is in surface contact with the cooling path forming member 53 .

With the heat dissipating member 12, the heat dissipating member 12 and circuit elements such as the switching element 11 and the heat dissipating member 12 and the cooling path forming member 53 are thermally connected to each other. A heat transfer path with excellent heat dissipation can be formed from the heat generating component to the cooling path forming member 53 via the heat radiating member 12 . Heat-dissipating grease or the like having high thermal conductivity may be added between the heat-dissipating member 12 and the heat-generating component and between the heat-dissipating member 12 and the cooling path forming member 53 .

As materials for the heat dissipation member 12, metals such as copper, aluminum, gold, and silver, alloys thereof, inorganic substances such as aluminum oxide, aluminum nitride, and silicon nitride, and resin materials with high thermal conductivity can be used. As a resin material with high thermal conductivity, epoxy resin to which a filler having high thermal conductivity such as aluminum oxide or aluminum nitride is added can be used.

The heat dissipation member 12 is preferably made of an insulating material having a high electrical resistivity. When using the heat radiating member 12 with low electrical resistivity, it is preferable to use the cooling path forming member 53 with high electrical resistivity.

Moreover, it is preferable that the heat radiation member 12 has a width parallel to the circuit board 10 larger than that of the heat-generating components such as the switching elements 11, and is arranged near the center so as to cover the entire surface of the heat-generating components. With such an arrangement, the heat transfer path from the heat-generating component to the heat-dissipating member 12 can be expanded in the direction parallel to the circuit board 10, and the heat dissipation from the heat-generating component can be improved.

As shown in FIG. 3, the cooling unit 5 is composed of a cooling path forming member 53 and a cooling path 54 through which a cooling medium flows. The cooling path 54 is formed inside the cooling path forming member 53 . As the cooling medium, for example, an appropriate medium can be used, such as water to which a corrosion inhibitor, a deoxidizer, etc. are added as necessary, or an antifreeze solution containing ethylene glycol, propylene glycol, or the like.

The cooling path forming member 53 is made of a material with high thermal conductivity. The cooling path forming member 53 can be provided in an outer shape such as a rectangular parallelepiped having approximately the same width as the space so as to fit in the space inside the housing 2 . Cooling pipes 51 and 52 are provided on the side surface of the cooling path forming member 53 so as to protrude outward. The cooling pipes 51 and 52 form through holes that communicate the outside of the cooling path forming member 53 and the cooling path 54 inside.

As materials for the cooling path forming member 53 and the cooling pipes 51 and 52, light alloys such as aluminum alloys, magnesium alloys, and titanium alloys, copper, copper alloys, bulk resins, and the like can be used. From the viewpoint of improving the cooling capacity and reducing the weight of the unit, the material of the cooling path forming member 53 is preferably a material with high thermal conductivity and low density, and particularly preferably a light alloy.

The cooling path 54 can be provided inside the cooling path forming member 53 in an arbitrary path or flow path shape. The cooling path 54 communicates with the cooling pipes 51 and 52 as inlets and outlets, and is liquid-tight except for the inlets and outlets. The cooling path 54 may have a single channel or a plurality of channels inside the cooling channel forming member 53 . For example, the plurality of flow paths can be provided symmetrically adjacent to each other for each power converter.

A cooling unit can be connected to the cooling pipes 51 and 52 via pipes, tubes, or the like. A cooling medium can be introduced into the cooling path forming member 53 through one of the cooling pipes. The cooling medium that has taken heat through the cooling passage 54 can be discharged to the cooling unit through the other cooling pipe. The cooling medium can be circulated between the cooling path 53 and the cooling unit while the power conversion unit 1 is in operation, on standby, or the like.

According to the structure of the cooling part 5 as described above, the heat generated in the heat-generating parts such as the switching element 11 during the operation of the unit is transferred to the heat-dissipating member 12 and then transferred from the heat-dissipating member 12 to the cooling path forming member 54 . The heat of the cooling path forming member 54 is removed by the cooling medium flowing through the cooling path 53 . The cooling medium that has received heat from the cooling path forming member 54 is discharged to the outside of the housing 2 through one of the cooling pipes 51 and 52 .

Therefore, the cooling unit 5 can forcibly cool the heat-generating components such as the switching element 11 . A higher cooling capacity can be obtained compared to the natural heat dissipation method in which a heat dissipation member that penetrates the inside and outside of the housing is provided. In addition, in order to exhaust the heat inside the housing 2 to the outside, the housing 2 has an adiabatic structure except for the through holes 21a, 21b for the cooling pipes and the through holes 22a, 22b, 23a, 23b for the terminals. can be set to

Inside the housing 2, there is provided a space for accommodating built-in components such as the input-side power conversion unit 3, the output-side power conversion unit 4, the cooling unit 5, and the like. The input-side power converter 3 , the output-side power converter 4 , and the cooling unit 5 can be accommodated and fixed inside the housing 2 . These built-in items may be detachably fixed to the housing 2 or may be irremovably fixed.

As a method of fixing to the housing 2, there is a method of fitting into the inside of the housing 2, a method of adhering to the housing 2 using an adhesive or the like, and a method of mechanically joining to the housing 2 using a joint part such as a bolt. An appropriate method can be used, such as a method of

When a method of fitting inside the housing 2 or a method of adhering to the housing 2 is used, built-in components such as the input side power conversion unit 3, the output side power conversion unit 4, the cooling unit 5, etc. are attached to the housing. 2, or the size with interference added. According to the fitting method, fixing and removal can be easily performed without using an adhesive or joining parts. Further, when the built-in objects are brought into close contact with the housing 2, the porous housing 2 functions as a cushioning material against vibrations and impacts, thereby preventing failure of the built-in objects.

In FIG. 3 , the space inside the housing 2 contains air in a region excluding built-in components such as the input-side power conversion unit 3 , the output-side power conversion unit 4 , the cooling unit 5 , and the like. The housing 2 is preferably provided with a highly airtight structure inside, except for the through holes 21a, 21b for cooling pipes and the through holes 22a, 22b, 23a, 23b for terminals. The gaps between these through holes and the cooling pipes and terminals are preferably sealed with a caulking material, packing, or the like.

If the housing 2 has a highly airtight structure, it will be highly resistant to the external environment in which the unit is placed, for example, the temperature and pressure that deviate from normal temperature and pressure, and temperature and pressure changes. Since the internal environment can easily be kept normal with respect to the external environment, it is possible to suppress the deterioration of the operation and performance of the built-in components of the housing and the deterioration of the properties of the built-in components. In addition, since it becomes difficult for dust, moisture, and the like to enter the inside of the housing 2, dielectric breakdown due to tracking can be suppressed.

FIG. 4 is a diagram showing an example of a circuit incorporated in the power conversion unit.
As shown in FIG. 4 , a circuit incorporated in the power conversion unit 1 is formed by an input side power conversion section 3 and an output side power conversion section 4 . The input power converter 3 and the output power converter 4 are electromagnetically coupled via a high frequency transformer 19 .

In the power conversion unit 1 that performs AC/DC conversion, the input side power conversion section 3, the output side power conversion section 4 and the high frequency transformer 19 form a resonant DC-DC converter together with the AC-DC converter. The high-frequency transformer 19 is accommodated in the space inside the housing 2, such as on the side of the input-side power conversion unit 3, the output-side power conversion unit 4, and the cooling unit 5 (on the front side or the back side in FIG. 3). can be done.

The input-side power conversion section 3 includes a first bridge circuit section 13 a, a second bridge circuit section 13 b, a resonance capacitor 15 , a smoothing capacitor 16 , and a primary coil of a high frequency transformer 19 . The output-side power conversion section 4 includes a third bridge circuit section 13 c, a smoothing capacitor 16 , and a secondary coil of a high frequency transformer 19 .

Each of the bridge circuit sections 13a, 13b, and 13c is formed as a full-bridge type circuit by the switching element 11 and a free wheel diode connected in anti-parallel. As the switching element 11, a semiconductor element such as a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), an IGBT (Insulated Gate Bipolar Transistor), GaN, Si, or SiC can be used.

The first bridge circuit section 13 a is electrically connected between positive and negative terminals on the input side of the input side power conversion section 3 . A smoothing capacitor 16 is connected in parallel to the first bridge circuit section 13a. The smoothing capacitor 16 of the input-side power conversion section 3 is connected in parallel with the second bridge circuit section 13b. A resonance circuit is connected in parallel to the midpoint of the second bridge circuit section 13b.

The resonance circuit includes the primary coil of the high frequency transformer 19 and the resonance capacitor 15 . A primary coil of the high-frequency transformer 19 is electrically connected between positive and negative terminals of the input-side power converter 3 . A secondary coil of the high-frequency transformer 19 is electrically connected between positive and negative terminals of the output-side power converter 4 .

The middle point of the third bridge circuit section 13c is connected in parallel to the secondary coil of the high frequency transformer 19 . A smoothing capacitor 16 is connected in parallel to the third bridge circuit section 13c. The smoothing capacitor 16 of the output power converter 4 is electrically connected between positive and negative terminals on the output side of the output power converter 4 .

An alternating current is input from the power supply to the first bridge circuit section 13a through the input terminals 31 and 32 . The input AC current is full-wave rectified and converted into a DC current. In the second bridge circuit section 13b, the DC current is converted into an AC current such as a square wave. The high frequency transformer 19 converts alternating current into high frequency. The resonance capacitor 15 reduces the switching loss by reducing the current/voltage during switching due to resonance. In the third bridge circuit section 13c, alternating current is converted into direct current.

According to the circuit shown in FIG. 4, switching loss is reduced by the resonant DC-DC converter, so even if the frequency is high, AC/DC conversion can be performed while suppressing power loss. In addition, since the power loss can be suppressed and the power can be converted to a high frequency, there is no need to use a large core for the high frequency transformer 19, and the size of the transformer can be reduced. Therefore, if it is incorporated in the power conversion unit 1, the size and weight of the unit can be reduced.

Here, specific performances of the power conversion unit 1 and the housing 2 will be described.

In the power conversion unit 1, the input side power conversion section 3, the output side power conversion section 4, and the input terminals 31 and 32 and the output terminals 41 and 42 drawn out of the housing 2 are electrically insulated from each other. There is a need. In addition, it is necessary to prevent not only short circuits between terminals and wiring, but also partial discharges occurring in materials.

Partial discharge is a discharge unnecessary for circuit operation that occurs in voids or the like in materials, and causes deterioration of the electrical insulation of materials and failure of circuit elements and the like. If the material is porous, the presence of voids in the material will cause partial discharge in the material, degrading the properties of the material. Even resins with high electrical resistivity may cause dielectric breakdown, so insulation performance and insulation design are required.

Japanese Industrial Standard JIS C61800-5-1:2016 and International Electrotechnical Commission Standard IEC 61800-5-1:2007 define creepage distances of solid insulators. Creepage distance is defined as the distance along the surface of a solid insulator. Creepage distances are defined in stages depending on the operating voltage, pollution degree and insulating material group, taking into consideration the deterioration of solid insulation due to long-term use.

The degree of pollution is classified into stages of 1 to 4 according to the presence of contaminants such as dust in the air and the conductivity of the contaminants. The insulating material groups are divided into Group I (CTI≧600 V), Group II (600 V>CTI≧400 V), Group IIIa (400 V>CTI≧175 V), Group IIIb ( 175V>CTI≧100V).

Pollution degree 1 is a condition in which there is no fouling or only dry, non-conductive fouling occurs, which does not affect the insulation. Contamination degree 2 is a state in which only non-conductive contamination occurs, and is a state in which it is expected that the device will temporarily become conductive due to dew condensation when the device is stopped. Pollution degree 3 is the condition where either conductive fouling or dry, non-conductive fouling that becomes conductive due to the expected condensation occurs. Pollution degree 4 is a state in which contamination that produces continuous conductivity occurs due to conductive dust, rain, snow, or the like.

A comparative tracking index (CTI) is measured according to JIS C 2134 and IEC60112. The CTI is measured using a test apparatus in which a pair of platinum electrodes are tilted so that their tip ends are close to each other at a predetermined distance. A predetermined electrolyte solution is dropped between the electrodes of the test apparatus at predetermined time intervals, and the maximum voltage that does not cause dielectric breakdown due to tracking is determined for voltage sweeps between the electrodes. Insulating material groups are defined for each degree of pollution according to the range of the highest voltage.

The operating voltage of the power conversion unit 1 is not particularly limited, but is preferably 800 V or higher, more preferably 1250 V or higher, from the viewpoint of use in applications requiring high output. Also, the operating voltage can be 2500V or less, or 1250V or less. In the range of operating voltages above 800 V, the insulating material group IIIb is deprecated if the pollution degree is 3. Therefore, the housing 2 of the power conversion unit 1 preferably belongs to the insulating material group I, II or IIIa.

That is, it is preferable that the housing 2 of the power conversion unit 1 has a comparative tracking index (CTI) of 175 V or higher, which is measured according to IEC60112. With such performance, even if the operating voltage is as high as 800 V or higher, partial discharge can be suppressed on the surface of the housing 2 which is porous. Even if there are open pores on the surface of the housing 2, deterioration and dielectric breakdown of the housing 2 are unlikely to occur, and a highly reliable unit that can be used in various environments can be obtained.

In the power conversion unit 1, the creepage distance of the solid insulator can be designed according to the usage environment, but is preferably 20 mm or more. That is, the creepage distance between the input terminal 32 and the output terminal 41, the creepage distance between the input terminal 31 and the input terminal 32, and the creepage distance between the output terminal 41 and the output terminal 42 should be 20 mm or more. preferable. With such a design, the insulation performance around the terminals can be ensured in various environments including an environment where the pollution degree is 3.

Although the operating temperature of the power conversion unit 1 is not particularly limited, it is preferably -40°C or higher and 50°C or lower. Within such a range, the internal temperature can be appropriately maintained by the housing 2 which is porous. Temperatures that deviate from room temperature and temperature changes can be mitigated, and the operation and performance of the internal components of the housing and the properties of the materials of the internal components can be maintained normally, so deterioration and failure of the unit can be suppressed.

The usage environment of the power conversion unit 1 is not particularly limited, but it can be used at low and medium altitudes of less than 0 m above sea level, 0 m or more and less than 5000 m, high altitudes of 5000 m or more and 15000 m or less, and atmospheric pressures corresponding to these altitudes. etc. At an altitude of 0m above sea level, the temperature drops by about 30°C at 5000m, and drops by about 60°C at 10000m. Even in such a usage environment, the internal air pressure can be appropriately maintained by the porous housing 2 . By alleviating air pressure that deviates from normal pressure and changes in air pressure, the operation and performance of the built-in components of the housing and the properties of the materials of the built-in components can be maintained normally, so deterioration and failure of the unit can be suppressed. .

The electrical resistivity of the housing 2 is preferably 10 ¹² Ω·m or more. The thermal conductivity and thickness of the housing 2 are not particularly limited. The thermal conductivity of the housing 2 can be appropriately designed according to the temperature of the usage environment, temperature changes, and the like. The thickness of the housing 2 can be appropriately designed according to the temperature of the usage environment, temperature change, atmospheric pressure, atmospheric pressure change, weight of internal objects, load area of internal objects, and the like. The thickness of the housing 2 may be different for each surface, or may be different for each in-plane portion.

The thermal conductivity of the housing 2 is preferably less than 0.10 W/mK, more preferably less than 0.05 W/mK. If the unit is placed in an extremely low or high temperature environment, or exposed to extreme temperature changes, the circuit elements will malfunction or deteriorate. When the heat conductivity of the porous housing 2 is less than 0.10 W/mK, the internal temperature can be appropriately maintained compared to a general housing made of bulk resin.

For example, in the case of polystyrene, which is widely used as a heat insulating material, the thermal conductivity of bulk resin is about 0.10 W/mK near room temperature. When a modified polyphenylene ether ( ^mPPE ) foam is used as the material of the housing 2, the thermal conductivity of the housing 2 is It has been confirmed by a test using a prototype that it can be reduced to about 0.034 W/mK.

That is, mPPE foamed at an expansion ratio of 10 times or more has a thermal conductivity suppressed to about ⅓ of that of bulk polystyrene, which is widely used as a heat insulating material. The transfer rate of heat quantity is about 1/3 when the thickness is the same, and about 1/5 when the weight is the same. Therefore, by adjusting the foaming ratio, density, etc. and lowering the thermal conductivity within the range where closed pores are maintained to a certain extent, the speed of temperature change inside the housing will be slowed down, and the probability of failure will be reduced. can be made

The thickness of the housing 2 is preferably 5 mm or more. When the weight of the internals of the housing 2 is 2 kg, and the pressure applied to the bottom upper surface of the housing 2 by the load of the internals is 0.2 MPa, an mPPE foam with a density of 0.1 g/cm ³ is used. It has been confirmed in a test using a prototype that a built-in object can be supported with a thickness of 5 mm. mPPE is a material excellent in moldability, mechanical strength, flame retardancy, chemical resistance, and the like.

The density of housing 2 is preferably less than 0.9 g/cm ³ . Polyethylene has a low density among synthetic resins, and its bulk density is about 0.9 g/cm ³ . When bulk polyethylene is used as the material of the housing 2, the weight ratio of the housing 2 to the entire unit is about 59%. If the density is less than 0.9 g/cm ³ , the weight ratio of the housing 2 will be lower than before, so the weight of the unit will be reduced. For example, for a foam with a density of 0.1 g/cm ³ , the weight percentage of housing 2 is reduced to about 6%.

It should be noted that increasing the foaming ratio or decreasing the density of the porous housing 2 reduces the mechanical strength such as the bending strength while reducing the weight. Therefore, the housing 2 must be provided with a certain thickness according to the weight of the built-in items, the load area of the built-in items, and the like. However, when the thickness increases, the volume of the unit as a whole increases, which hinders miniaturization of the unit. Therefore, it is preferable to set the thickness and density of the housing 2 within the range of required performance according to the weight of the internal objects, the load area of the internal objects, and the like.

FIG. 5 is a perspective view showing an example of the division structure of the housing when the housing is viewed from the front side. FIG. 6 is a perspective view showing an example of the division structure of the housing when the housing is viewed from the rear side. 5 and 6 show the same housing.
As shown in FIGS. 5 and 6, the casing of the power conversion unit, which is made porous, can be provided in a split structure that can be split into two members on one side.

In FIGS. 5 and 6, the case 2A, which has a split structure, can be divided along one plane passing through cooling pipe through holes 21a and 21b and terminal through holes 22a, 22b, 23a and 23b. ing. Reference numeral 110 in the drawing represents a dividing surface where the members constituting the housing 2A are divided, and also represents abutting surface where the members are butted against each other when they are joined.

As shown in FIG. 5, on the front side of the housing 2A, through holes 21a and 21b for drawing out the cooling pipes 51 and 52 can be provided near the center of the front surface in the vertical direction. Further, as shown in FIG. 6, through holes 22a and 22b for drawing out the input terminals 31 and 32 are provided on the upper side of the rear surface in the vertical direction and on one side in the horizontal direction on the rear surface side of the housing 2A. can be done. Further, through holes 23a and 23b for drawing out the output terminals 41 and 42 can be provided on the lower side in the vertical direction of the rear surface and the opposite side in the horizontal direction. Such an arrangement of through holes is suitable for securing creepage distances and clearances for electrical insulation, and for accommodating internal components at different heights so that they can be individually fixed and removed.

The housing 2A, which has a divided structure, is composed of a lower member 20a located on the lower side in the vertical direction and an upper member 20b located on the upper side in the vertical direction. The lower member 20a and the upper member 20b can divide the substantially rectangular parallelepiped housing 2A by one dividing plane 110 passing through the cooling pipe through holes 21a and 21b and the terminal through holes 22a, 22b, 23a and 23b. As shown, the dimension in the height direction is changed for each height of the through hole. The lower member 20a and the upper member 20b are each formed with a partial hole which is notched in a semi-columnar shape and serves as a through hole when the lower member 20a and the upper member 20b are abutted.

Inside the housing 2A having a split structure, a space is provided to accommodate built-in components such as the input side power conversion section 3, the output side power conversion section 4, the cooling section 5, and the like. The input-side power converter 3, the output-side power converter 4, and the cooling unit 5 may or may not be fixed in advance to each main body member constituting the housing 2A.

According to the housing 2A having such a divided structure, the internal space can be easily opened and closed, so that the input side power conversion unit 3, the output side power conversion unit 4 and the cooling unit 5 can be accommodated in the housing 2A, Ejection from 2A can be easily performed. Therefore, the assembly of the unit, the electrical insulation test of the built-in items, the inspection of the built-in items, the replacement of parts, etc. can be easily performed without disassembling the unit.

In particular, if it is provided in a structure that can be divided at one dividing plane passing through all the through holes, the cooling pipes 51, 52 and the terminals 31, 32, 41, 42 can be inserted into the respective through holes when accommodating the built-in components. Instead, the built-in object can be placed on the lower member 20a and closed with the upper member 20b so as to be pulled out to the outside. In addition, it is possible to easily take out the accommodated built-in items to the outside. Therefore, damage to the cooling pipes 51 and 52, the terminals 31, 32, 41 and 42, and the housing 2 can be reduced when the built-in items are accommodated or removed.

FIG. 7A is a top view showing an example of a joining structure of a housing, in which a main part of the housing provided in the divided structure is enlarged. FIG. 7B is a cross-sectional view showing an example of the joint structure of the housing, in which the main part of the housing provided in the divided structure is enlarged. FIG. 7B corresponds to a cross-sectional view taken along line II of FIG. 7A. 7A and 7B show an enlarged view of one of the four corners near the abutment surface 110 between the lower member 20a and the upper member 20b of the housing 2A having a split structure. .
As shown in FIGS. 7A and 7B, the housing having a split structure can be provided in a structure in which the members forming the housing are joined together by fitting.

As shown in FIG. 7A, locking holes 24 can be provided in a mating surface 110 against which a mating member is mated in the housing 2A having a split structure. The locking hole 24 can be provided in the mating surface 110 of one of the members constituting the housing 2</b>A of the divided structure so as to open in a direction perpendicular to the mating surface 110 .

As shown in FIG. 7B, a projecting portion 25 that can be inserted into the locking hole 24 can be provided on the abutment surface 110 of the mating member that abuts against the member provided with the locking hole 24 . The projecting portion 25 can be provided on the mating surface 110 of one of the members constituting the housing 2</b>A of the split structure so as to protrude in a direction perpendicular to the mating surface 110 .

The locking hole 24 and the projecting portion 25 are provided in mutually-fitting shapes at positions facing each other. The locking hole 24 and the projecting portion 25 may be joined by adhesion or welding as a molded component to the members constituting the split-structure housing 2A. It is preferable to integrally mold with.

An arbitrary number of locking holes 24 and protrusions 25 can be provided for the members constituting the housing 2A having a split structure. The vertical relationship between the locking hole 24 and the protrusion 25 is not particularly limited. The locking holes 24 and the protrusions 25 can be provided at the corners of the abutment surface 110 against which the mating members are abutted, intermediate portions on the sides of the abutment surface 110, and the like. In particular, from the viewpoint of increasing the strength of bonding between members, it is preferable to provide them at four corners and one or more locations on the sides in the longitudinal direction.

In this way, in the housing 2A having a split structure, if one member constituting the housing 2A is provided with the protrusion 25 and the other member is provided with the locking hole 24 into which the protrusion 25 is inserted and secured, The members can be joined together by butting the members together and fitting the locking holes 24 and the protrusions 25 together. In the closed state of the housing 2A, it is possible to prevent unintentional opening, displacement of members, falling off, etc., so that the internal contents of the housing 2A can be protected against temperature and atmospheric pressure that deviate from the usage environment, temperature and atmospheric pressure changes, and tracking. It can be adequately protected from factors such as dust and moisture.

7A and 7B, the protrusion 25 having a substantially spherical recess is fitted into the locking hole 24 having a substantially spherical recess so that the movement of the member is restrained in the horizontal and vertical directions. It's becoming However, the shapes of the locking hole 24 and the protrusion 25 are not particularly limited as long as the movement of the member is restrained in the horizontal direction. It is preferable that the locking hole 24 and the protrusion 25 have a narrow opening side, a barb, a claw, or the like so that they do not easily come off from the fitted state.

FIG. 8 is a cross-sectional view of a power conversion unit according to a modification of the invention.
As shown in FIG. 8, the power conversion unit having a porous housing can also be in the form of a power unit 1A according to a modification in which the space inside the housing 2 is filled with a filler 7. FIG.

Similar to the power conversion unit 1, the power conversion unit 1A according to the modification includes a housing 2 forming an outer shell, an input-side power conversion unit 3 for converting input power, and a power converter for converting and outputting power. and a cooling unit 5 for cooling heat-generating components.

In the power conversion unit 1A, internal components such as an input side power conversion section 3, an output side power conversion section 4, a cooling section 5, and the like are accommodated in the space inside the housing 2. FIG. The filling material 7 can be filled in a space inside the housing 2 other than the built-in objects. Other configurations of the power conversion unit 1A are the same as those of the power conversion unit 1 described above.

The filler 7 is made of a material with high electrical resistivity and low thermal conductivity. As the filler 7, molded resin or a coating material similar to that used for insulating circuit elements can be used. As the molded resin, the same resin as that of the housing 2 can be used in bulk. As the coating material, adhesive gel may be used, or self-adhesive rubber or the like may be used.

The filling material 7 is interposed between the circuit board 10 and the housing 2, between the circuit board 10 and the heat radiation member 12, and between the circuit board 10 and the cooling path forming member 54. is filled in the space inside the If a molded resin is used, it can be housed with the internals. When a coating material is used, the space can be filled and hardened after the built-in object is accommodated. One or more of the surface of the circuit elements, the surface of the circuit board 10 and the inner surface of the housing 7 can be coated with a coating material.

According to such a mode of filling with the filler 7, vibrations and shocks to the built-in components of the housing 2 can be suppressed as compared with the case where the filling material 7 is filled with air. When the unit is filled with air, depending on the location where the unit is installed, the built-in objects may be subject to direct external vibration or impact, causing deterioration or breakage of the built-in objects. On the other hand, when the filling material 7 is filled, the fixing strength of the built-in object can be improved and the force to the built-in object can be dispersed. Therefore, it is possible to suppress deterioration, breakage, etc. of the built-in components and improve the reliability of the unit.

FIG. 9 is a perspective view showing an example of the divided structure of the housing when the housing is viewed from the front side. FIG. 10 is a perspective view showing an example of the divided structure of the housing when the housing is viewed from the rear side. 9 and 10 show the same housing.
As shown in FIGS. 9 and 10, the porous housing of the power conversion unit can also be provided in a multi-layer split structure that can be split on a plurality of surfaces.

In FIGS. 9 and 10, the case 2B having a multi-layer split structure can be divided at a plurality of planes passing through cooling pipe through holes 21a and 21b and terminal through holes 22a, 22b, 23a and 23b. there is Reference numeral 110 in the drawing represents a dividing surface where the members constituting the housing 2B are divided, and also represents a butting surface where the members are butted against each other when they are joined.

As shown in FIG. 9, on the front side of the housing 2B, through holes 21a and 21b for drawing out the cooling pipes 51 and 52 can be provided near the center of the front surface in the vertical direction. Further, as shown in FIG. 10, through holes 22a and 22b for drawing out the input terminals 31 and 32 are provided on the upper side of the rear surface in the vertical direction and on one side in the horizontal direction on the rear surface side of the housing 2B. can be done. Further, through holes 23a and 23b for drawing out the output terminals 41 and 42 can be provided on the lower side in the vertical direction of the rear surface and the opposite side in the horizontal direction. Such an arrangement of through holes is suitable for securing creepage distances and clearances for electrical insulation, and for accommodating internal components at different heights so that they can be individually fixed and removed.

The housing 2B having a multi-layer split structure has a main body of a split structure of four splits, and furthermore, the top cover can be split from such a main body. The housing 2B is formed of main body members 20c, 20d, 20e, and 20f forming a box-shaped main body, and a lid member 20g forming a lid covering the opening of the box-shaped main body. The lid member 20g is provided so that it can be opened and closed independently so that the internal contents can be easily viewed when opened.

The body portion of the housing 2B having a split structure includes a first body member 20c positioned at the lowest level in the vertical direction, a second body member 20d positioned at the second level, and a third body member 20e positioned at the third level. and a fourth body member 20f located on the uppermost stage.

The main body members 20c, 20d, 20e, and 20f are rectangular parallelepiped so that they can be divided at a plurality of dividing surfaces 110 passing through the cooling pipe through holes 21a, 21b and the terminal through holes 22a, 22b, 23a, and 23b, respectively. , and are laminated while forming division planes 110 parallel to each other. The main body members 20c, 20d, 20e, and 20f are each formed with partial holes that are notched in a semi-columnar shape to form through holes that are butted against each other.

Inside the housing 2B having a split structure, a space is provided to accommodate built-in components such as the input side power conversion section 3, the output side power conversion section 4, the cooling section 5, and the like. The input-side power converter 3, the output-side power converter 4, and the cooling unit 5 may or may not be fixed in advance to each main body member constituting the housing 2B.

According to the housing 2B having such a split structure, the input side power conversion section 3, the output side power conversion section 4, and the cooling section 5 can be accommodated in order in the internal space to assemble a unit. In addition, it becomes possible to individually expose the built-in objects to the outside, to store them individually, and to take them out individually. By opening at a specific dividing surface 110, it is possible to check specific points such as electrical connection points and thermal connection points of the built-in components. Therefore, it is possible to easily assemble the unit, test the electrical insulation of the built-in items, inspect the built-in items, and replace parts.

In FIGS. 9 and 10, the case 2B having a split structure has a split structure in which the main body is divided into four parts. can be set to an appropriate number of divisions. The housing 2B has a separable cover, but the bottom may be separable, or the body may be separable without the cover and the bottom being separable. .

FIG. 11A is a top view showing an example of a joint structure of a housing, in which a main part of the housing provided in the divided structure is enlarged. FIG. 11B is a cross-sectional view showing an example of the joint structure of the housing, in which the main part of the housing provided in the divided structure is enlarged. FIG. 11B corresponds to a cross-sectional view along line II-II of FIG. 11A. 11A and 11B show an enlarged view of one of the four corners near the abutment surface 110 between the first body member 20c and the second body member 20d of the housing 2B having a split structure. exemplified.
As shown in FIGS. 11A and 11B, the housing having a split structure can also be provided in a structure in which the members constituting the housing are joined together by fastening with joining parts.

As shown in FIG. 11A, a through-hole 26 can be provided in a mating surface 110 with which a mating member is mated in a casing 2B having a split structure. The through hole 26 can be formed by providing a flange extending outward on the mating surface 110 of the member constituting the housing 2B so as to penetrate through the mating surface 110 on the flange in the vertical direction.

The through-holes 26 may be joined by adhesion, welding, or the like as molded parts to the members forming the split-structure housing 2B. preferably.

As shown in FIG. 11B, when joining the members constituting the housing 2B, a joining part 27a such as a bolt is inserted into the through hole 26. As shown in FIG. By fastening a joint part 27b such as a nut to the inserted joint part 27a, the members can be fixed to each other. When bolts and nuts are used as the joint parts 27a and 27b, the members can be freely joined and divided. The joint parts 27a and 27b are preferably parts made of an insulating material such as resin.

An arbitrary number of through-holes 26 can be provided in the members constituting the housing 2B having a split structure. The through-holes 26 can be provided at the corners of the abutment surface 110 against which the mating members are abutted, intermediate portions on the sides of the abutment surface 110, and the like. In particular, from the viewpoint of increasing the strength of bonding between members, it is preferable to provide them at four corners and one or more locations on the sides in the longitudinal direction.

In FIGS. 11A and 11B, through hole 26 and joining parts 27a and 27b join first body member 20c and second body member 20d. can be provided so as to join the members of The through hole 26 can be provided concentrically so as to pass through a plurality of members. The joint parts 27a and 27b can improve the strength and rigidity as a whole by providing a length that penetrates a plurality of members.

In FIG. 11A, the through hole 26 is provided on the outer flange. If so, the abutment surface 110 may be provided with an inwardly extending inner flange and may be provided on the inner flange. Moreover, it may be provided on the abutment surface 110 so as to penetrate the side wall of the housing 2B without providing a flange.

In FIGS. 11A and 11B, the first main body member 20c and the second main body member 20d are joined to each other, but one or more of the members constituting the housing of the split structure are joined by fastening with joining parts. can be provided in the structure. Besides bolts and nuts, screws, rivets, pins, snap pins, clips, and the like may be used as joining parts. Depending on the joining method, a flange for holding a clip or the like, a concave portion, or the like may be provided without providing the through hole 26 .

FIG. 12 is a perspective view showing an example of the rib structure of the housing when the housing is viewed from the rear side.
As shown in FIG. 12, the porous housing of the power conversion unit may have ribs 28 on the surface for the purpose of extending the creepage distance for electrical insulation and strengthening the mechanical strength. . In FIG. 12, a plurality of ribs 28 are provided on the rear surface side of the housing 2 from which the terminals 31, 32, 41, 42 are drawn for the purpose of extending the creepage distance between the terminals.

The ribs 28 are molded integrally with the main body of the housing 2 . In FIG. 12 , the rib 28 is provided as a protrusion having a substantially rectangular cross-sectional shape and protrudes outside the housing 2 . The ribs 28 are provided in a plurality of rows between the through holes through which the input terminals 31 and 32 and the output terminals 41 and 42 are passed so as to separate the through holes. The rib 28 extends from the lower end to the upper end of the rear surface of the housing 2 .

In FIG. 12, the ribs 28 are provided on the outer surface of the housing 2, but are preferably provided on the inner surface of the housing 2 for the purpose of extending the creepage distance between the terminals. That is, they are provided symmetrically between the inside and outside so as to project to the inside of the housing 2 between the through holes through which the input terminals 31 and 32 and the output terminals 41 and 42 are passed. is preferred.

When such ribs 28 are provided, the creeping distance between the terminals is extended along the surfaces of the ribs 28 by the total distance of the width and height of the ribs 28, thereby improving the tracking resistance of the housing 2. can be done. Between the input terminals 31 and 32 and the output terminals 41 and 42 drawn to the outside, the surface of the housing 2, which is porous, makes it difficult for partial discharge to occur. can be prevented.

The ribs 28 can be provided with an appropriate cross-sectional shape, width, length, and height depending on the purpose of the ribs 28 . The position of the ribs 28 is not limited to between terminal through-holes, but is provided on one or more of the rear surface, front surface, bottom surface, top surface, and side surface of the housing 2 according to the purpose of the ribs 28. be able to. Moreover, it can be provided on any of the outer surface, the inner surface, or both the outer surface and the inner surface of the housing 2 .

When the ribs 28 are provided for the purpose of strengthening the mechanical strength, the ribs 28 may be provided in any structure such as a single row, a plurality of parallel rows, or a plurality of crossing rows in a grid pattern. Moreover, it is good also as a leg structure, a damper structure, etc., provided in block shape. By providing such ribs 28, it is possible to increase the mechanical strength and rigidity of a specific portion of the housing 2, so that external vibrations and impacts can be alleviated, and the load from internal components can be supported. can do.

Next, a power converter according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 13 is a perspective view of the power conversion device according to the embodiment of the present invention as viewed from the front side.
As shown in FIG. 13, the power conversion device 100 according to this embodiment includes a plurality of power conversion units 1 and frames 101, 102, 103, 104, and 105 that accommodate and support the power conversion units 1. ing. A power conversion device 100 has a configuration in which a plurality of power conversion units 1 supported in frames 101, 102, 103, 104, and 105 are electrically connected to each other in series or in parallel.

The frames 101, 102, 103, 104, and 105 are configured by combining a pair of left and right side plates 101, a top plate 102, a bottom plate 103, a plurality of vertical partition members 104, and a plurality of horizontal partition members 105. ing. These members are joined together by joining parts such as screws, bolts and nuts. These members can be made of appropriate materials such as metals and resins.

A pair of left and right side plates 101, a top plate 102, and a bottom plate 103 form a rectangular parallelepiped box whose front and rear surfaces are open. The vertical partition member 104 is vertically supported inside the box and divides the inside of the box into a plurality of horizontally arranged spaces. The horizontal partition member 105 is laterally supported inside the box, and partitions the inside of the box into a plurality of vertically arranged shelves.

The power conversion unit 1 is placed or fixed on each shelf sectioned in a grid pattern. In FIG. 13, the power conversion units 1 are stacked in three rows of seven stages, but the number of stages, the number of rows, and the number of units accommodated by the frame are not particularly limited. Each of the side plate 101, the top plate 102, the bottom plate 103, the vertical partition member 104, and the horizontal partition member 105 may be composed of one member, or may be composed of a plurality of members.

The power conversion units 1 are connected in series or parallel to each other via wires connected to terminals 31, 32, 41, 42, and the entire unit is electrically connected to a main machine such as a power supply, motor, storage battery, and the like. can do. For example, the negative terminal can be grounded. Also, the power conversion unit 1 can be connected to a cooling unit via a pipe, a tube, a manifold, or the like connected to the cooling pipes 51 and 52 .

According to such a power conversion device 100, since a plurality of units are provided, a device that realizes high power conversion and redundancy of the power conversion function is provided. In addition, since a plurality of units can be housed in a small exclusive area due to the frame structure, space can be saved. Moreover, since the cooling pipes 51 and 52 drawn out from each unit can be arranged, the efficiency and ease of forcibly cooling each unit can be improved.

In FIG. 13, the pair of left and right side plates 101, top plate 102, and bottom plate 103 form a rectangular parallelepiped box with open front and rear surfaces. As long as it is possible, the box may be a box whose front or rear surface is not open, or a box whose front or rear surface is provided with a door or sheet that can be freely opened and closed. According to such a box, it is possible to further suppress the intrusion of dust, moisture, and the like.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and includes various modifications without departing from the technical scope. For example, the above embodiments are not necessarily limited to having all the configurations described. Also, it is possible to replace part of the configuration of an embodiment with another configuration, or add another configuration to the configuration of a certain embodiment. Moreover, it is also possible to add another configuration, delete a configuration, or replace a part of the configuration of a certain embodiment.

For example, the configurations of FIGS. 3, 7, 8, 11 and 12 can be applied in combination with the divided structures of FIGS. 5 and 6 and the divided structures of FIGS. The same applies to division structures other than those shown in FIGS. The casings 2 and 2A are made of resin and are porous. A reinforcing material or the like may be provided.

The air-filled structure of FIG. 3 and the filler-filled structure of FIG. 8 may be partially combined in one unit. For example, if the space adjacent to the input-side conversion unit 3 in the space around the input-side conversion unit 3 is filled with a filling material, and the remaining space is filled with air, heat transfer to the housing 2 is suppressed. , it may be possible to increase the strength.

Further, the power conversion unit 1 is provided with through holes for cooling pipes and through holes for terminals on the front surface and the rear surface. The number, shape and the like are not particularly limited. The number of cooling pipes may be one as long as it penetrates the inside and outside of the housing, like a heat pipe, and the number of through holes for cooling pipes may be one. In addition, they may be separately provided on one or more of the rear surface, front surface, lower surface, upper surface, and side surface of the housing, or may be provided collectively. In addition to the through holes for cooling pipes and the through holes for terminals, through holes for other functions may be provided.

The power conversion unit 1 is configured to perform AC/DC conversion. It may be a device that performs conversion. Also, the circuit for AC/DC conversion is not limited to the circuit shown in FIG.

Moreover, the cooling path forming member 53 and the cooling pipes 51 and 52 may be provided integrally, or may be provided separately and joined to each other. The cooling path forming member 53 may be composed of one functional unit, or may be composed of a plurality of functional units. A packing such as an O-ring can be attached to these joints to prevent leakage of the cooling medium.

1 power conversion unit 2 housing 3 input side power conversion section 4 output side power conversion section 5 cooling section 7 filler 10 circuit board 11 switching element 12 heat radiation member 13 rectifier circuit 15 resonance capacitor 16 smoothing capacitor 20a lower member 20b upper member 20c First body member 20d Second body member 20e Third body member 20f Fourth body member 20g Lid member 21a Through hole 21b Through hole 22a Through hole 22b Through hole 23a Through hole 23b Through hole 24 Locking hole 25 Protrusion 26 Through hole 27a Joint part 27b Joint part 28 Rib 31 Input terminal 32 Input terminal 41 Output terminal 42 Output terminal 51 Cooling pipe 52 Cooling pipe 53 Cooling passage forming member 54 Cooling passage 101 Side plate (frame)
102 top plate (frame)
103 bottom plate (frame)
104 Vertical partition member (frame)
105 horizontal partition member (frame)

Claims (10)

a cooling unit through which a cooling medium flows; an input-side power conversion unit arranged on one side of the cooling unit; and an output-side power conversion unit arranged to face the input-side power conversion unit with the cooling unit interposed therebetween. and a housing covering the cooling unit, the input-side power conversion unit, and the output-side power conversion unit, wherein the input-side power conversion unit and the output-side power conversion unit include a switching element and a circuit board. and wherein the housing is porous. In the power conversion unit according to claim 1,
The housing is a power conversion unit that is a foamed body obtained by foaming a resin, or a molded body obtained by dispersing pores in a resin matrix. In the power conversion unit according to claim 1,
A power conversion unit, wherein the comparative tracking index (CTI) of the housing is 175V or more. In the power conversion unit according to claim 1,
A power conversion unit, wherein the housing has a thermal conductivity of less than 0.10 W/mK. In the power conversion unit according to claim 1,
A power conversion unit, wherein the housing has a density of less than 0.9 g/cm ³ . In the power conversion unit according to claim 1,
The housing has a terminal through-hole for drawing a terminal to the outside from the circuit board, and a cooling pipe through-hole for drawing a cooling pipe to the outside from the cooling unit. A power conversion unit having a structure that can be divided along a plane that passes through one or more of the through holes and the through holes for the cooling pipes. In the power conversion unit according to claim 6,
The housing has a projection on one of the members that can be separated from each other, and has a locking hole into which the projection is inserted and locked in the other member, and the projection is inserted into the locking hole. and a power conversion unit in which the members are joined together. In the power conversion unit according to claim 6,
The housing has a through hole into which a joining part can be inserted into one member and the other member that can be separated from each other, and the members are joined together by fastening by the joining part inserted into the through hole. conversion unit. In the power conversion unit according to claim 1,
The housing has a plurality of through-holes for drawing out terminals from the circuit board, and the terminals are arranged between the through-holes for terminals on the outside and inside of the housing. A power conversion unit having ribs for electrical isolation. A plurality of the power conversion units according to any one of claims 1 to 9, and a frame that accommodates and supports the power conversion units, wherein the plurality of power conversion units are supported in the frame. A power converter in which units are electrically connected to each other in series or parallel.

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