WO2021166341A1 - Power conversion unit and power conversion device - Google Patents

Abstract

The present invention comprises: a primary-side unit (10A) having a primary-side circuit body (11A) having a switching element (21A) and a circuit board (22A), and a primary-side housing (24A) that accommodates the primary-side circuit body (11A); a secondary-side unit (10B) having a secondary-side circuit body (11B) having a switching element (21B) and a circuit board (22B), and a secondary-side housing (24B) that accommodates the secondary-side circuit body (11B); and a cooling path (32) formed from a cooling pipe (31) positioned between the primary-side circuit body (11A) and the secondary-side circuit body (11B).

Description

Power conversion unit and power conversion device

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

_{CO 2} emission regulations are being tightened around the world to curb global warming. As an alternative to engines that use fossil fuels, electrification of power systems is being actively promoted. On the other hand, future power electronics devices (power electronics devices) are required to have an output density (power electronics device output / power electronics device volume) that is more than double the current output density. Therefore, as the related technology, a technology for drastically improving the cooling performance and increasing the voltage is required.
In addition, the partial discharge generation voltage drops under low pressure, which is encountered by high-altitude aircraft. For example, in a low pressure environment, the partial discharge start voltage is significantly lower than that under atmospheric pressure. Therefore, it is necessary to apply a solid or liquid having a partial discharge start voltage about 10 times higher than that of air on the surface to which the voltage is applied and the surface to be grounded. However, when a failure occurs in an individual part, it is generally difficult to repair the part surrounded by a solid.
Patent Document 1 and Patent Document 2 are related to these techniques.

[Summary] of Patent Document 1 provides a power conversion device capable of achieving both "[problem] suppression of surge voltage, high heat dissipation of SW element, and suppression of ringing. [Solution] Two The element modules 10H and 10L of the SW element are laminated in the thickness direction so that the side surfaces S1 are parallel to each other in the same direction via the insulating layer 20, and are already connected to the positive terminal (+) of one SW element. A power conversion device 100 in which the negative terminals (-) of one of the SW elements are arranged so as to overlap each other in the thickness direction. ", And the technology of the power conversion device is disclosed. As described above, Patent Document 1 discloses a technique of a power conversion device in which two switching elements are laminated in the height direction, a grounding conductor is provided inside, and a cooling path is provided in the grounding conductor.

In the [Summary] of Patent Document 2, "[Problem] Propulsion system for an aircraft is provided. [Solution] The propulsion system (300) for an aircraft (10) includes a power supply (302) and an electric motor. The propulsion system (300) is also driven by an electric motor (312), including an electric propulsion assembly (304) having (312) and a propulsion unit (314). Includes a power bus (306) that electrically connects to the electric propulsion assembly (304). The power supply (302) is configured to power the power bus (306) and the power bus (306) is 800. It is configured to transmit power to the electric propulsion assembly (304) at a voltage above the volt. ", Disclosing the technology of propulsion systems for aircraft. As described above, Patent Document 2 discloses a propulsion system for an electric motor in which electric power is passed through an inverter converter controller by an electric power bus corresponding to a high voltage exceeding 800 V, and then the motor is driven by the converted electric power. ing. In addition, there is a description about the insulation configuration that suppresses partial discharge and the installation of a cooling mechanism to cope with the heat generation of the power bus for electric motors that operate at low pressure and high voltage.

JP 2015-056925 Japanese Unexamined Patent Publication No. 2018-184162

In Patent Document 1, the rated voltage is 1 kV or less, that is, in a power conversion device in which the inside of the unit is air-insulated, the structure is effective in consideration of the balance between the insulating property and the cooling property of the entire unit. However, for high-voltage power converters for which it is difficult to apply air insulation, it is difficult to replace parts in a solid or liquid-insulated power conversion unit when an abnormality occurs in the cooling mechanism such as leakage. Therefore, there is a problem (problem) that the loss cost at the time of failure is high because all the replacements are performed. Further, there is a problem (problem) that regular maintenance for corrosion of the cooling path is impossible.

In Patent Document 2, the insulation structure that achieves both high cooling performance and high insulation performance is insufficient only by the partial discharge countermeasure and the cooling countermeasure of the electric power bus, and the electric motor and the electric power converter are placed in a low pressure environment (for example, high altitude). There is a problem (problem) that it is difficult to operate on an aircraft.

An object (object) of the present invention is to provide a power conversion unit (power conversion device) having a cooling structure for improving the output density and reliability of the power conversion unit in order to cope with the above problems.

In order to solve the above-mentioned problems, the present invention was configured as follows.
That is, the power conversion unit of the present invention includes a primary side unit having a switching element and a circuit board, a primary side housing including the primary side circuit board, and a switching element. A secondary side unit including a secondary side circuit body having a circuit board, a secondary side housing for accommodating the secondary side circuit board, the primary side circuit body, and the secondary side circuit body. It is characterized in that it is provided with a cooling passage by a cooling pipe arranged between the two.

In addition, other means will be described in the form for carrying out the invention.

According to the present invention, it is possible to provide a power conversion unit (power conversion device) having a cooling structure for improving the output density and reliability of the power conversion unit (power conversion device).

It is a figure which shows typically the structural example of the electric power conversion unit which concerns on 1st Embodiment of this invention by the cross-sectional structure of the side surface. It is a figure which shows typically the structural example in which the electric power conversion unit which concerns on 1st Embodiment of this invention is housed in the frame in a panel, in the cross-sectional structure of a side surface. It is a figure which shows typically the appearance of the power conversion unit shown in FIG. 1A as a bird's-eye view. It is a figure which shows typically the cross-sectional structure of the power conversion unit shown in FIG. 1A as a bird's-eye view. It is a figure which shows the outline of the device structure which flows the cooling medium through the cooling path by the cooling pipe of a power conversion unit schematically. It is a figure which shows typically the structural example of the electric power conversion unit which concerns on 2nd Embodiment of this invention by the cross-sectional structure of the side surface. It is a figure which shows typically the structural example which housed the electric power conversion unit which concerns on 2nd Embodiment of this invention in the frame in a panel by the cross-sectional structure of the side surface. It is a figure which shows typically the appearance of the power conversion unit shown in FIG. 4A as a bird's-eye view. It is a figure which shows typically the cross-sectional structure of the power conversion unit shown in FIG. 4A as a bird's-eye view. It is a figure which shows typically the structural example of the electric power conversion unit which concerns on 3rd Embodiment of this invention by the cross-sectional structure of the side surface. It is a figure which shows typically the structural example of the electric power conversion unit which concerns on 4th Embodiment of this invention by the cross-sectional structure of the side surface. It is a figure which shows typically the structural example of the liquid leakage detection of the power conversion unit which concerns on 5th Embodiment of this invention as a bird's-eye view. It is a figure which shows typically the structural example of the electric power conversion unit which concerns on 6th Embodiment of this invention by the cross-sectional structure of the side surface. It is a figure which shows typically the structural example of the electric power conversion unit which concerns on 7th Embodiment of this invention by the cross-sectional structure of the side surface. It is a figure which shows typically the structural example of the electric power conversion unit which concerns on 8th Embodiment of this invention by the cross-sectional structure of the side surface. It is a figure which shows the 1st circuit configuration example of the power conversion unit which concerns on 1st Embodiment of this invention. It is a figure which shows the 2nd circuit configuration example of the power conversion unit which concerns on 1st Embodiment of this invention. It is a figure which shows the 3rd circuit configuration example of the power conversion unit which concerns on 1st Embodiment of this invention. It is a figure which shows the circuit structure example of the power conversion apparatus which combines any power conversion unit of the embodiment of this invention with the circuit structure shown in FIG. 14 and converts a three-phase AC voltage into a DC voltage. It is a figure which shows the circuit structure example of the power conversion apparatus which combines any power conversion unit of the embodiment of this invention with the circuit structure shown in FIG. 12, and converts it into the DC voltage of a different voltage.

Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as “embodiments”) will be described as appropriate with reference to the drawings.

<< First Embodiment >>
The configuration of the power conversion unit 100 according to the first embodiment of the present invention will be described with reference to FIGS. 1A, 1B, 2A, and 2B.
FIG. 1A is a diagram schematically showing a configuration example of the power conversion unit 100 according to the first embodiment of the present invention in a cross-sectional structure on the side surface.
FIG. 1B is a diagram schematically showing a configuration example in which the power conversion unit 100 according to the first embodiment of the present invention is housed in the in- panel frames 1001A and 1001B by the cross-sectional structure of the side surface.
FIG. 2A is a diagram schematically showing the appearance of the power conversion unit 100 shown in FIG. 1A as a bird's-eye view.
FIG. 2B is a diagram schematically showing a cross-sectional structure of the power conversion unit 100 shown in FIG. 1A as a bird's-eye view.

In FIG. 1A, the power conversion unit 100 includes a primary side unit 10A, a secondary side unit 10B, and a cooling path 32 by a cooling pipe 31.
The primary side unit 10A includes a primary side circuit body 11A and a primary side housing 24A.
The primary side circuit body 11A is equipped with an electric circuit (primary side circuit board 22A, a plurality of switching elements 21A, and electric / electronic components such as capacitors and reactors (not shown in the cross section of FIG. 1)). Electronic circuit). In FIG. 1A, the number and arrangement of the plurality of switching elements 21A are schematically shown for convenience of notation, and do not directly correspond to the arrangement (arrangement) of the switching elements in FIG. 2B described later.
Further, in FIG. 1A, a portion having high electrical stress such as around the switching element of the primary circuit body 11A is sealed with silicone gel 23A.
The primary side circuit body 11A is housed in the primary side housing 24A.

The secondary side unit 10B includes a secondary side circuit body 11B and a secondary side housing 24B.
The secondary side circuit body 11B comprises a secondary side circuit board 22B, a plurality of switching elements 21B, and electric / electronic components such as capacitors and reactors (not shown) to form an electric circuit (electronic circuit). There is.
Silicone gel 23B is used to seal the portion of the secondary circuit body 11B where electrical stress is high, such as around the switching element.
The secondary side circuit body 11B is housed in the secondary side housing 24B.

The cooling passage 32 provided by the cooling pipe 31 is arranged so as to be sandwiched between the primary side unit 10A and the secondary side unit 10B. Further, as shown in FIG. 1A, in the primary side unit 10A and the secondary side unit 10B, the cooling passage 32 is provided on the plane having the widest cross-sectional area. With this configuration, it is possible to secure the maximum area where the cooling medium is filled in the cooling path (liquid cooling path) 32.
The primary side unit 10A and the secondary side unit 10B are arranged so as to have a symmetrical shape with the center of the cooling path 32 as the center line 40. By arranging in this way, it is possible to reduce variations in temperature rise in a plurality of switching elements.

The cooling pipes 31 constituting the cooling passage 32 are separately provided in contact with the primary side housing 24A and the secondary side housing 24B at the upper part and the lower part of the center line 40, respectively, and are separately provided with the primary side unit 10A. Combined when assembling the secondary side unit 10B.
Further, the cooling pipe 31 constituting the cooling passage 32 has a ground potential (ground potential). Metals such as aluminum, stainless steel, and copper are applied to the structural members of the cooling pipe 31 constituting the cooling passage 32.
The refrigerant flowing in the cooling passage (liquid cooling passage) 32 is a liquid, and examples thereof include water, mineral oil, fluorinert, and vegetable oil.

In the regions of the primary side unit 10A and the secondary side unit 10B, a solid, liquid, or gel-like material is used, and an air region (gas region) does not exist. For example, the silicone gel 23A is applied to a portion having high electrical stress such as around the switching element 21A.
With these structures, the insulating property is improved, and even if a partial discharge occurs and the solid insulation is deteriorated, the insulating property can be easily repaired by replacing the fluid silicone gel.
In addition, since the electrical stress is slightly low in the area where high voltage is directly applied or in the unit (primary side unit 10A, secondary side unit 10B) that does not come into contact with the grounding part, a simpler insulating material is used. It is also possible to apply. Examples of the simple insulating material include PPS (Polyphenylene sulfide) resin, epoxy resin, and unsaturated polyester.

FIG. 1B is a diagram schematically showing a configuration example in the case where the power conversion unit 100 shown in FIG. 1A is housed in the in- panel frames 1001A and 1001B as a power conversion device, in a cross-sectional structure on the side surface, as described above. Is.
The power conversion unit 100 is actually used by being housed in and fixed to the in- panel frames 1001A and 1001B as the power conversion device.
FIG. 1B is different from FIG. 1A in that the in- panel frames 1001A and 1001B are shown, and the other parts are the same as those in FIG. 1A.

As described above, FIG. 2A is a diagram schematically showing the appearance of the power conversion unit 100 shown in FIG. 1A as a bird's-eye view.
In FIG. 2A, the power conversion unit 100 is configured by combining the primary side unit 10A and the secondary side unit 10B. The joint (joint with a built-in liquid cooling tube) 61 serves to join the primary side unit 10A and the secondary side unit 10B, and is also connected to the cooling passage 32 (FIG. 1) inside to pass the cooling medium through the liquid cooling tube (non-liquid cooling tube). (Shown).
When there are a plurality of power conversion units 100, a plurality of power conversion units are connected between the plurality of power conversion units 100 via a joint (joint with a built-in liquid cooling tube) 61 and a cooling pipeline (62: FIG. 3). 100 is also cooled.
Further, in FIG. 2A, the IA-IA axis shows the cross section of FIG. 1A, and the IIB-IIB axis shows the cross section of FIG. 2B described later.

FIG. 2B is a diagram schematically showing a cross-sectional structure of the power conversion unit 100 shown in FIG. 1A as a bird's-eye view, as described above.
In FIG. 2B, the cooling passage 32 provided by the cooling pipe 31 is provided on a vertically symmetrical dividing surface of the primary side unit 10A and the secondary side unit 10B.
Further, the plurality of switching elements 21A are housed in the primary side housing 24A. Further, the primary side housing 24A is provided with a wiring hole 71 through which electrical wiring from the outside of the primary side unit 10A is passed.
As described above, the number and arrangement of the plurality of switching elements 21A are schematically shown for convenience of notation, and do not directly correspond to the arrangement (arrangement) of the switching elements in FIG. 1A described above.

As shown in FIG. 2B, a cooling path (liquid cooling path) 32 is provided between the primary side unit 10A (input side) and the secondary side unit 10B (output side) to cool the power conversion unit 100. ..
By adopting such a structure, the cooling performance for increasing the output density of the power conversion unit 100 (power conversion device) and the insulation reliability under low atmospheric pressure are ensured. For example, the output density of the power conversion unit 100 (power conversion device) is 10 [kW / cc] or more, and the rated voltage is 1 [kV] or more.

A circuit configuration example of the power conversion unit 100 and a circuit configuration example of a power conversion device combining the power conversion unit 100 will be described later.

<Device configuration in which a cooling medium flows through the cooling path of the power conversion unit>
FIG. 3 is a diagram schematically showing an outline of a device configuration for flowing a cooling medium (cooling liquid) through a cooling passage (liquid cooling passage) 32 by a cooling pipe 31 (FIG. 1A) of the power conversion unit 100. In FIG. 3, the in- panel frames 1001A and 1001B (FIG. 1B) are not shown.
In FIG. 3, the joint (joint with a built-in liquid cooling tube) 61 of the power conversion unit 100 is connected to one of the cooling pipelines (cooling pipe connecting portion) 62. Further, the other end of the cooling pipeline 62 is connected to the pump 65. The pump 65 sends a cooling medium (cooling liquid) to the heat exchanger 66 via the cooling pipeline 63. The heat exchanger 66 cools the cooling medium and sends the cooling medium from the other joint (liquid cooling tube built-in joint) 61 of the power conversion unit 100 to the inside of the power conversion unit 100 via the cooling pipeline 64.

The power conversion unit 100 is cooled by the above device configuration.
In addition, in FIG. 3, the case of one power conversion unit 100 is shown. When there are a plurality of power conversion units 100 (multiple units), a plurality of power conversion units are connected between the plurality of power conversion units 100 via a joint (joint with a built-in liquid cooling tube) 61 and a cooling pipeline (62, 64). 100 is also cooled.

<Summary of the first embodiment>
In the power conversion unit 100 of the first embodiment shown in FIG. 1A, a cooling passage (liquid cooling passage) 32 is provided between the primary side unit 10A and the secondary side unit 10B to provide the power conversion unit 100. Cooling. Further, the cooling passage 32 is provided on the plane having the widest cross-sectional area at the boundary surface between the primary side unit 10A and the secondary side unit 10B. With this configuration, it is possible to secure the maximum area filled with the cooling medium.
By adopting such a structure, the cooling performance for increasing the output density of the power conversion unit 100 (power conversion device) and the insulation reliability under a low pressure are ensured. Further, it is possible to reduce the variation in temperature rise in the plurality of switching elements 21A and 21B.
Since insulation reliability can be ensured, partial discharge in the space where the substrate of the power conversion unit is arranged is suppressed, and a highly reliable power conversion unit and power conversion device are realized.
Further, the above-mentioned configuration has an effect of sharing the cooling path 32 to improve the output density of the power conversion device and reducing the weight.

Further, since the cooling path 32 is provided with the divided surface (40), the corrosion state can be monitored and repaired in order to prevent the cooling path surface in contact with the cooling medium from being corroded.
Further, since the unit is provided with a dividing surface in the cross section including the cooling passage 32, even if the switching element becomes defective, only one of the divided units can be replaced, as compared with the case where all of the divided units are replaced. The loss cost can be reduced. In addition, it is easy to inspect parts other than switching elements and replace defective parts.
Further, since the silicone gels 23A and 23B are used in the parts having high electrical stress such as around the switching elements 21A and 21B, even if a partial discharge occurs and the solid insulation deteriorates, there is fluidity. Insulation repair can be easily performed by replacing the silicone gel.

<Effect of the first embodiment>
According to the power conversion unit of the first embodiment of the present invention, since a cooling path (liquid cooling path) is provided between the primary side unit and the secondary side unit, cooling for increasing the output density is provided. In addition to ensuring improved performance and insulation reliability under low pressure, the output density of the power conversion unit is improved.
In addition, it is possible to reduce variations in temperature rise in a plurality of switching elements.
Since insulation reliability can be ensured, partial discharge in the space where the substrate of the power conversion unit is arranged can be suppressed, and a highly reliable power conversion unit and a power conversion device can be provided.
Further, the cooling path (liquid cooling path) is shared to improve the output density of the power conversion device, which has the effect of reducing the weight.
Further, since the cooling path (liquid cooling path) is provided with a divided surface, it is possible to monitor and repair the corrosion state of the cooling path surface in contact with the cooling medium.
Further, even if the switching element becomes defective, only one of the divided units can be replaced, and the loss cost can be reduced as compared with the case where all of the divided units are replaced. In addition, parts inspection, repair, and replacement of defective parts are easy.

<< Second Embodiment >>
The configuration of the power conversion unit 200 according to the second embodiment of the present invention will be described with reference to FIGS. 4A, 4B, 5A, and 5B.
FIG. 4A is a diagram schematically showing a configuration example of the power conversion unit 200 according to the second embodiment of the present invention in cross-sectional structure on the side surface.
FIG. 4B is a diagram schematically showing a configuration example in which the power conversion unit 200 according to the second embodiment of the present invention is housed in the in- panel frames 1001A and 1001B by the cross-sectional structure of the side surface.
FIG. 5A is a diagram schematically showing the appearance of the power conversion unit 200 shown in FIG. 4A as a bird's-eye view.
FIG. 5B is a diagram schematically showing a cross-sectional structure of the power conversion unit 200 shown in FIG. 4A as a bird's-eye view.

The power conversion unit 200 of the second embodiment in FIG. 4A differs from the power conversion unit 100 of the first embodiment in FIG. 1A at the boundary (division surface) between the primary side unit 10A and the secondary side unit 10B. , The leak sensor (leakage detecting means) 51 shown in FIG. 4A is provided, and the O-ring 52 for preventing the leak is further provided.
In the power conversion device mounted on a moving body or the like, the waterproof mechanism may be mechanically broken due to vibration due to load fluctuation or impact at the time of takeoff and landing, and liquid may leak.
Therefore, by providing the liquid leakage sensor (liquid leakage detecting means) 51, it is possible to detect an abnormality at an early stage and perform maintenance.
Further, two O-rings are arranged so as to sandwich the liquid leakage sensor (liquid leakage detecting means) 51. By arranging the O-rings in duplicate, the risk of liquid leakage is reduced.

As described above, the power conversion unit 200 in FIG. 4A differs from the power conversion unit 100 in FIG. 1A in that it is provided with a liquid leakage sensor (leakage detecting means) 51 and an O-ring 52, and the others are shown in FIG. Since it is the same as 1A, a duplicate description will be omitted.

FIG. 4B is a diagram schematically showing a configuration example in the case where the power conversion unit 200 shown in FIG. 4A is housed in the in- panel frames 1001A and 1001B as the power conversion device, in a cross-sectional structure on the side surface, as described above. Is.
It is used by accommodating and fixing the power conversion unit 200 in the in- panel frames 1001A and 1001B as the power conversion device.
FIG. 4B is different from FIG. 4A in that the in- panel frames 1001A and 1001B are shown, and the other parts are the same as those in FIG. 4A, so that the duplicated description will be omitted.

As described above, FIG. 5A is a diagram schematically showing the appearance of the power conversion unit 200 shown in FIG. 4A as a bird's-eye view.
The power conversion unit 200 in FIG. 5A differs from the power conversion unit 100 in FIG. 2A in that the liquid leakage sensor (liquid leakage detecting means) 51 is shown in FIG. 5A. Since the O-ring 52 is arranged inside the power conversion unit 200 and cannot be seen from the outside, it is not shown in FIG. 5A.
Further, in FIG. 5A, the IVA-IVA axis shows the cross section of FIG. 4A, and the VB-VB axis shows the cross section of FIG. 5B described later.
Others are the same as those in FIG. 2A, so duplicate description will be omitted.

The power conversion unit 200 in FIG. 5B differs from the power conversion unit 100 in FIG. 2B in that the liquid leakage sensor (leakage detecting means) 51 and the O-ring 52 are shown in FIG. 5B. Others are the same as in FIG. 2B, so duplicate description will be omitted.

<Effect of the second embodiment>
According to the second embodiment of the present invention, in addition to the effect of the first embodiment, by providing a liquid leakage sensor (liquid leakage detecting means), it becomes possible to detect an abnormality at an early stage and perform maintenance.
In addition, the risk of liquid leakage is reduced by arranging the O-rings in duplicate.

<< Third Embodiment >>
FIG. 6 is a diagram schematically showing a configuration example of the power conversion unit 300 according to the third embodiment of the present invention in cross-sectional structure on the side surface.
The power conversion unit 300 of the third embodiment in FIG. 6 is different from the power conversion unit 100 of the first embodiment in FIG. 1B (FIG. 1A) at the boundary between the primary side unit 10A and the secondary side unit 10B (the boundary between the primary side unit 10A and the secondary side unit 10B). The split surface) is provided with the liquid leakage detection sheet (liquid leakage detecting means) 53 shown in FIG. 6 on the outer side surfaces of the units (primary side unit 10A and secondary side unit 10B).
The liquid leakage detection sheet 53 detects the liquid leakage in the cooling medium of the cooling passage 32 including the cooling pipe 31 of the power conversion unit 300 as discoloration of the sheet or other changes.

The liquid leakage detection sheet 53 provided as shown in FIG. 6 has an advantage that it is relatively easy to install, and can be performed as a part of the work in an application in which a periodic inspection is performed on a daily basis.
Further, in the power conversion unit 300 as shown in FIG. 6, since the dividing surface (boundary) between the primary side unit 10A and the secondary side unit 10B is wide, if liquid leakage occurs in a part, the entire divided surface is covered. Leakage can be detected. Therefore, the liquid leakage detection sheet 53 exerts its function if it is provided on a part of the divided surface.
Others are the same as those in FIG. 1B (FIG. 1A), so duplicate description will be omitted.

<Effect of the third embodiment>
According to the liquid leakage detection sheet (liquid leakage detection means) of the third embodiment of the present invention, it is relatively easy to install, and it is performed as a part of work in an application in which periodic inspection is performed on a daily basis. Can be done.
Further, if the liquid leakage detection sheet 53 is provided on a part of the divided surface, it has an effect of exerting a function.

<< Fourth Embodiment >>
FIG. 7 is a diagram schematically showing a configuration example of the power conversion unit 400 according to the fourth embodiment of the present invention in cross-sectional structure on the side surface.
The power conversion unit 400 of the fourth embodiment in FIG. 7 is different from the power conversion unit 300 of the third embodiment in FIG. 6 as a liquid leakage detection means, instead of the liquid leakage detection sheet 53, an IC tag type liquid leakage. It is equipped with a detector 54.
The IC tag type leak detector 54 has an IC (Integrated Circuit) built-in and has a wireless function. It is also possible to eliminate the need for batteries by utilizing the ionizing action of the leaked liquid. In the case of a structure that does not require a battery, it is possible to save the trouble of battery replacement.
Further, as described above, the IC tag type liquid leakage detector has an IC built-in and has a wireless function, so that it can be constantly monitored. In addition, since no power supply or wiring work is required, the installation cost can be reduced.
Others are the same as those in FIG. 1B (FIG. 1A), so duplicate description will be omitted.

<Effect of Fourth Embodiment>
According to the fourth embodiment of the present invention, in addition to the effect of the first embodiment, by providing the IC tag type leak detector 54, it is possible to constantly monitor the leak. In addition, since no power supply or wiring work is required, the installation cost can be reduced.

<< Fifth Embodiment >>
FIG. 8 is a diagram schematically showing a configuration example of liquid leakage detection of the power conversion unit according to the fifth embodiment of the present invention as a bird's-eye view.
In FIG. 8, the sound listening rod 55 is attached to a joint (joint with a built-in liquid cooling tube) 61 of a power conversion unit (for example, a power conversion unit 100), and the signal detected by the sound listening rod 55 is transmitted by sound waves or radio waves to the sound listening analysis unit. Communicate to 56.
That is, the diagnosis is performed using the sound listening rod 55 as the liquid leakage detection means (leakage detection method).

Regarding the leakage of the cooling medium from the cooling path 32 of the power conversion unit 100, the sound listening rod 55 has the housings 24A and 24B as the sound in the normal state where there is no leakage and the sound in the abnormal state where the leakage is generated. It detects as a sign that it changes subtly due to vibrations exerted on it.
By applying machine learning or the like to the sound obtained by the sound listening rod 55, the sound listening analysis unit 56 can detect a slight change in the sound, and the liquid generated before the leakage occurs. It is also possible to detect subtle cracks in cold channels.
Others are the same as those in FIG. 2A, so duplicate description will be omitted.

<Effect of the fifth embodiment>
According to the fifth embodiment of the present invention, in addition to the effect of the first embodiment, the sound listening rod 55 and the sound listening analysis unit 56 can be provided to monitor the leakage. Furthermore, by applying machine learning or the like to the sound and hearing analysis unit 56, it is possible to detect a delicate crack in the liquid cooling path that occurs before the leakage occurs.

<< 6th Embodiment >>
FIG. 9 is a diagram schematically showing a configuration example of the power conversion unit 500 according to the sixth embodiment of the present invention in cross-sectional structure on the side surface.
The power conversion unit 500 of the sixth embodiment in FIG. 9 is different from the power conversion unit 200 of the second embodiment in FIG. 4B (FIG. 4A) in that the power conversion unit 500 is divisible in FIG. It has structural surfaces 81A and 81B.
In the power conversion unit 500 shown in FIG. 9, a plurality of switching elements (21A, 21B) existing in the unit (power conversion unit 500) and associated members (for example, the copper plate and the heat conductive layer of FIG. 11 described later) and the like. The structure should be divisible by the unit of peripheral insulation).
With this structure, even if one switching element is broken, the range of replacing parts can be minimized, and the loss cost can be minimized.
Others are the same as those in FIG. 4B (FIG. 4A), so duplicate description will be omitted.

<Effect of the sixth embodiment>
According to the sixth embodiment of the present invention, in addition to the effect of the second embodiment, the switching element is one by forming a structure that can be divided into units of a plurality of switching elements existing in the unit and members associated therewith. Even if it breaks, the range of parts replacement can be minimized, and the loss cost can be minimized.

<< 7th Embodiment >>
FIG. 10 is a diagram schematically showing a configuration example of the power conversion unit 600 according to the seventh embodiment of the present invention in a cross-sectional structure on the side surface.
The power conversion unit 60 of the seventh embodiment in FIG. 10 is different from the power conversion unit 200 of the second embodiment in FIG. 4B (FIG. 4A) in that the cooling pipe 31 constituting the cooling passage (32) is different from the power conversion unit 200 of the second embodiment. By providing the cooling fins (cooling pipe protrusions) 31B or the concavo-convex structure of the cooling fins 31B on the inner surface of the above, the surface area inside the cooling pipe 31 for liquid cooling is increased.
With this structure, the cooling function of the cooling pipe 31 constituting the cooling passage (32) is improved.
Others are the same as those in FIG. 4B (FIG. 4A), so duplicate description will be omitted.

<Effect of the 7th embodiment>
According to the seventh embodiment of the present invention, in addition to the effect of the second embodiment, the surface area inside the cooling pipe to be liquid-cooled is increased by providing an uneven structure with cooling fins on the inner surface of the cooling pipe. , The cooling function of the cooling pipes constituting the cooling path is improved.

<< Eighth Embodiment >>
FIG. 11 is a diagram schematically showing a configuration example of the power conversion unit 700 according to the eighth embodiment of the present invention with a cross-sectional structure on the side surface.
In FIG. 11, the power conversion unit 700 includes a primary side unit (10A: FIG. 4A), a secondary side unit (10B: FIG. 4A), and a cooling path (32: FIG. 1A) by a cooling pipe 31. ing.
The primary side unit (10A) includes a primary side circuit body 11A9. Further, the secondary side unit (10B) includes a secondary side circuit body 11B9.
The power conversion unit 700 is characterized by the primary side circuit body 11A9 and the secondary side circuit body 11B9.

The primary side circuit body 11A9 includes a primary side circuit board (22A: FIG. 4A) and a plurality of switching elements 21A.
A copper plate (first conductor) 91A is provided on the surface of the switching element 21A on the cooling pipe 31 side. Further, a heat conductive layer 92A composed of an insulating member is provided between the copper plate 91A and the cooling pipe 31.
Further, the cooling pipe 31 is connected to the ground potential (ground potential). Further, the member used for the heat conductive layer 92A shall have a heat conductivity of 0.5 [W / mK] or more. For the member of the heat conductive layer 92A, for example, an epoxy resin or a ceramic plate is applied.

Similarly to the primary circuit body 11A9, the secondary circuit body 11B9 of the secondary unit also has a copper plate (second conductor) 91B and a heat conductive layer 92B on the surface of the switching element 21B on the cooling pipe 31 side. It is provided. Since the secondary circuit body 11B9 and the primary circuit body 11A9 are substantially the same with respect to these copper plates and the heat conductive layer, overlapping description will be omitted.

With the above configuration, the heat generated by the plurality of switching elements 21A and 21B is transferred to the cooling pipe 31 (cooling path 32), and the temperatures of the primary side circuit body 11A9 and the secondary side circuit body 11B9, that is, the power conversion unit 700. Reduce the rise.

<Effect of the eighth embodiment>
According to the eighth embodiment of the present invention, the temperature rise of the power conversion unit is further increased by providing a copper plate (first conductor, second conductor) and a heat conductive layer between the plurality of switching elements and the cooling pipe. Reduce.

<About the frame in the board>
As shown as the power conversion unit 100 and the power conversion unit 200 in FIGS. 1A and 4A, the power conversion unit does not include the in- panel frames 1001A and 1001B shown in FIGS. 1B and 4B, respectively.
However, when used as a power conversion device, an in-panel frame is provided to structurally protect the power conversion unit. In addition, metals such as aluminum, stainless steel, and iron are applied to the frame inside the panel. In this way, by using metal for the in-panel frame, it is possible to electrically fix the potential of the in-panel frame.
A structure in which the power conversion unit is provided with an in-panel frame may be treated as a “power conversion unit”.

<About the cooling conduit outside the housing>
FIG. 3 schematically shows an outline of a device configuration for flowing a cooling medium (cooling liquid) through a cooling passage (liquid cooling passage) 32 by a cooling pipe 31 (FIG. 1A) of the power conversion unit 100.
In FIG. 3, the joint (joint with a built-in liquid cooling tube) 61 of the power conversion unit 100 is connected to one of the cooling pipelines (cooling pipe connecting portion) 62.
As the metal constituting the cooling pipeline (cooling pipe connecting portion) 62, a metal different from the metal constituting the cooling pipe 31 of the power conversion unit 100 is adopted. Specifically, as the metal constituting the cooling pipe line (cooling pipe connecting portion) 62, a metal having a higher ionization tendency than the metal constituting the cooling pipe 31 is applied. That is, the metal constituting the cooling pipe 31 has a lower ionization tendency than the metal forming the cooling pipeline (cooling pipe connecting portion) 62.

With this configuration, even when the cooling pipe 31 of the power conversion unit 100 is corroded by the coolant and ambient environment factors, the cooling pipe line (cooling pipe connection portion) 62 outside the power conversion unit 100 is first used. Corrodes quickly, so it is possible to know whether or not the cooling pipe 31 in the power conversion unit has corroded without opening the dividing surface of the power conversion unit 100. Therefore, maintenance of the power conversion unit 100 becomes easy.

<Circuit configuration example of power conversion unit>
Next, a circuit configuration example of the power conversion unit 100 will be described below.

<< First circuit configuration example of power conversion unit >>
FIG. 12 is a diagram showing a first circuit configuration example of the power conversion unit 100 according to the first embodiment of the present invention. The circuit configuration 810 shown in FIG. 12 is an example of a circuit having a function of a DC-DC converter.
The four switching elements 21A and the four switching elements 21B in FIG. 12 are the four switching elements 21A of the primary side circuit body 11A and the four switching elements 21B of the secondary side circuit body 11B, respectively, in FIG. It corresponds to.
In FIG. 12, diodes are connected in antiparallel to each of the switching elements 21A and 21B. As these diodes, diodes parasitic on the internal structure of the elements of the switching elements 21A and 21B may be used, or they may be provided externally.
Further, the diode connected in antiparallel to the switching element is described in FIGS. 13 and 14 described later, but the duplicate description of the diode in FIGS. 13 and 14 is omitted.

In FIG. 12, a primary side circuit (input side circuit) is configured by including four switching elements 21A, capacitors 1211, 1212, and a reactor 1213. Further, a secondary side circuit (output side circuit) is configured by including four switching elements 21B and a capacitor 1221. Further, a transformer 1201 is provided between the primary side circuit and the secondary side circuit, and electrically connects the primary side circuit and the secondary side circuit.
The four switching elements 21A are configured in a bridge type, and the four switching elements are controlled by PWM (Pulse Width Modulation) by a control circuit (not shown) to control the DC between the DC input terminals 12D1P and 12D1N. Converts the voltage to a sine wave and outputs it from the terminal of the bridge. The output voltage of this sine wave passes through the capacitor (resonant capacitor) 1212 and the reactor 1213, and the voltage is converted by the transformer 1201 and transmitted to the secondary circuit.

In the secondary side circuit, the four switching elements 21B are configured in a bridge type, and by controlling each of the four switching elements by a control circuit (not shown), a sine wave (alternating current) of the input terminal of the bridge is generated. It rectifies and outputs a DC voltage between the DC output terminals 12D2P and 12D2N.
Further, the output side capacitor 1221 and the input side capacitor 1211 both act as smoothing capacitors for smoothing the ripple voltage.
The switching elements 21A and 21B are composed of any of semiconductor elements such as IGBT (Insulated Gate Bipolar Transistor), IEGT (Injection Enhanced Gate Transistor), MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor), and Super Junction MOSFET. NS.
By configuring the circuit shown in FIG. 12 in this way, a DC-DC conversion circuit (power conversion device) that converts a DC voltage can be configured.

Although the power conversion unit 100 has been described, the circuit configuration 810 may be embodied by using any of the power conversion units 200, 300, 400, 500, 600, and 700.
The power conversion unit whose circuit is configured by the circuit configuration 810 is referred to as a power conversion unit 1810, and is used in FIG. 16 described later.

<< Example of second circuit configuration of power conversion unit >>
FIG. 13 is a diagram showing a second circuit configuration example of the power conversion unit 100 according to the first embodiment of the present invention. The circuit configuration 820 shown in FIG. 13 is an example of a circuit having a function of a single-phase AC-3 phase AC converter.
Although the circuit corresponding to the power conversion unit 100 has been described, the switching elements 21A and 21B in the power conversion unit 100 shown in FIG. 1 are described as four. However, in FIG. 1A, for convenience of notation, the number is shown as four, and the number is not limited to four. In FIG. 13, six switching elements 21B will be described.
In FIG. 13, a primary side circuit (input side circuit) is configured by including four switching elements 21A, a capacitor 1313, and reactors 1311, 1312. Further, a secondary side circuit (output side circuit) is configured by including six switching elements 21B.

The four switching elements 21A are configured in a bridge type and are controlled by a control circuit (not shown).
The AC voltage input to the input terminal of the bridge via the reactors 1311, 1312 is rectified by the four bridge-type switching elements 21A and converted into a DC voltage.
This DC voltage is smoothed by the capacitor 1313 and supplied as a DC power supply for the secondary side circuit (output side circuit).

In the secondary side circuit, in the series circuit of the two switching elements 21B, the two switching elements 21B are PWM-controlled by a control circuit (not shown), so that the AC voltage of one phase (for example, U phase) is generated. can get. Further, in the series circuit of the other two switching elements 21B, by PWM-controlling the two switching elements 21B with a control circuit (not shown), the AC voltage of the other one phase (for example, V phase) can be increased. can get. Further, in the series circuit of the two switching elements 21B, the two switching elements 21B are PWM-controlled by a control circuit (not shown), so that an alternating current for another one phase (for example, W phase) is obtained. The voltage is obtained.
As described above, the three-phase AC voltage is output to the AC output terminals 13A2U, 13A2V, 13A2W on the secondary side. That is, by configuring the power conversion unit 100 as a circuit configuration 820, a conversion circuit (power conversion device) that converts single-phase alternating current to three-phase alternating current can be configured.

<< Third circuit configuration example of the power conversion unit >>
FIG. 14 is a diagram showing a third circuit configuration example of the power conversion unit 100 according to the first embodiment of the present invention. The circuit configuration 830 shown in FIG. 14 is an example of a circuit having a function of an AC-DC converter.
The four switching elements 21A and the four switching elements 21B in FIG. 14 are the four switching elements 21A of the primary side circuit body 11A and the four switching elements 21B of the secondary side circuit body 11B, respectively, in FIG. It corresponds to.
Although it is described as "four switching elements 21A of the primary side circuit body 11A and four switching elements 21B of the secondary side circuit body 11B", in FIG. 14, the primary side circuit and the secondary side There is no distinction from the circuit, and the circuits in the primary side circuit body 11A and the secondary side circuit body 11B in FIG. 1 are used in parallel.

In FIG. 14, the four switching elements 21A are configured in a bridge type, and a sine wave input between the input terminals 14AP and 14AQ of the bridge by controlling each of the four switching elements by a control circuit (not shown). Is rectified, and a DC voltage is output between the DC output terminals 14DP and 14DN.
Further, the four switching elements 21B are configured in a bridge type, and the sine wave input between the input terminals 14AP and 14AQ of the bridge is rectified by controlling each of the four switching elements by a control circuit (not shown). Then, a DC voltage is output between the DC output terminals 14DP and 14DN.

That is, the two rectifier circuits each composed of the four switching elements are used by connecting the input and the output in parallel.
The capacitors 1411, 1421 are connected between the DC output terminals 14DP and 14DN to smooth the rectified DC voltage.
With the circuit configuration 830 shown in FIG. 14 above, the power conversion unit 100 is embodied in an AC-DC conversion circuit (AC-DC power conversion device).

Although the power conversion unit 100 has been described, the circuit configuration 830 may be embodied by using any of the power conversion units 200, 300, 400, 500, 600, and 700.
The power conversion unit whose circuit is configured by the circuit configuration 830 is referred to as a power conversion unit 1830, and is used in FIG. 15 described later.

<Summary of circuit configuration of power conversion unit>
The power conversion unit 100 includes a primary side circuit body 11A and a secondary side circuit body 11B, and the circuit configuration in these primary side circuit body 11A and the secondary side circuit body 11B has a high degree of freedom. .. That is, various power conversion units (power conversion devices) can be configured by mounting various elements on a circuit board and making various connections. For example, as described above, FIG. 12 shows an example of a DC-DC conversion circuit, FIG. 13 shows an example of a single-phase AC-3 phase AC conversion circuit, and FIG. 14 shows an example of an AC-DC conversion circuit.
As in these examples, various power conversion circuits (power conversion unit, power conversion device) can be configured by selecting elements and selecting circuits by wiring.

Further, as shown in FIG. 12, the circuit elements to be mounted are not limited to capacitors and reactors.
Further, as shown in FIG. 13, the number of switching elements in the primary side circuit body 11A and the secondary side circuit body 11B is not limited to four.
Further, as shown in FIG. 14, it is not necessary to limit the primary side circuit body 11A and the secondary side circuit body 11B as an input circuit and an output circuit, and the primary side circuit body 11A and the secondary side circuit body 11B are used. It may be used in parallel.
Further, although the power conversion unit has been described as the power conversion unit 100 shown in FIG. 1, the power conversion units 200, 300, 400, respectively shown in FIGS. 4A, 6, 7, 9, 10, and 11, respectively. Similar circuit configurations are possible for 500, 600, and 700.

<Circuit configuration example of a power conversion device using multiple power conversion units>
Next, an example of a circuit configuration of a power conversion device using a plurality of power conversion units will be described below.

<< First circuit configuration example of a power conversion device using a plurality of power conversion units >>
FIG. 15 shows a combination of a power conversion unit according to any one of the first to eighth embodiments of the present invention and a plurality of power conversion units 1830 according to the circuit configuration 830 shown in FIG. 14 to convert a three-phase AC voltage into a DC voltage. It is a figure which shows the circuit structure example of the power conversion apparatus 8000 which converts into.
In FIG. 15, the power conversion device 8000 includes three power conversion units (power conversion devices) 1830 having the AC-DC conversion function shown in FIG.

Further, in FIG. 15, AC voltages of each phase from the U phase, V phase, and W phase of the three-phase AC power supply 1550 are input to the three power conversion units 1830, respectively.
Each of the three power conversion units 1830 converts an AC voltage (AC power) into a DC voltage (DC power), and outputs each DC voltage (DC power) between the output terminals 15DP and 15DN.
As shown in FIG. 15, the output terminals of the three power conversion units 1830 are connected in parallel with each other.
As described above, the three-phase AC AC voltage is converted as a DC voltage, and the output power conversion device 8000 is embodied.

<< Second circuit configuration example of a power conversion device using a plurality of power conversion units >>
FIG. 16 shows that the power conversion unit according to any one of the first to eighth embodiments of the present invention is converted into a DC voltage having a different voltage by combining a plurality of power conversion units 1810 according to the circuit configuration 810 shown in FIG. It is a figure which shows the circuit structure example of the power conversion apparatus 9000.
In FIG. 16, the power conversion device 9000 includes three power conversion units (power conversion devices) 1810 having a DC-DC conversion function shown in FIG.
Further, in FIG. 16, DC voltages are input to the three power conversion units 1810 from the input terminals 16D1P and 16DIN for inputting the voltage of the DC power supply, respectively.
Each of the three power conversion units 1810 converts a DC voltage (DC1: FIG. 12) into a DC voltage (DC2: FIG. 12) having a different voltage. The output terminals of the three power conversion units 1810 are connected in series, and the sum of the DC voltages (3 × DC2) is output between the output terminals 16D2P and 16D2N of the power conversion device 9000.
As described above, the power conversion device 9000 in which the DC voltage is converted into a DC voltage having a different voltage and is output is embodied.

<Summary of power conversion equipment using multiple power conversion units>
Various power conversion devices can be configured by combining a plurality of power conversion units.
For example, as described above, FIG. 15 shows that a three-phase AC-DC conversion circuit can be configured by using three power conversion units 1830 (830: FIG. 14) of the AC-DC conversion circuit.
Further, FIG. 16 shows that a DC-DC conversion circuit that converts a DC voltage DC1 into a high-voltage DC voltage DC3 can be configured by using three power conversion units 1810 (810: FIG. 12) of the DC-DC conversion circuit. ing.
The power conversion device is not limited to the above example by combining a plurality of power conversion units. Further, in the example of the power conversion device shown in FIGS. 15 and 16, the example in which three power conversion units are used is not limited to three. You may combine four or more power conversion units.

<Insulation between in-panel frames of multiple power conversion units>
A power conversion device 8000 configured by combining a plurality of (three) power conversion units 1830 shown in FIG. 15 and a power conversion device 9000 configured by combining a plurality of (three) power conversion units 1810 shown in FIG. In, there may be a plurality of in-panel frames of the power conversion unit (for example, 1001A, 1001B: FIG. 1B) for each power conversion unit, and the ground voltages of the in-panel frames may differ from each other.
In this case, an insulating plate for ensuring insulation may be provided between different in-panel frames of different power conversion units.

<< Other Embodiments >>
The present invention is not limited to the embodiments described above, and further includes various modifications. For example, the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to those having all the described configurations. Further, it is possible to replace a part of the configuration of one embodiment with a part of the configuration of another embodiment, and further, add a part or all of the configuration of another embodiment to the configuration of one embodiment. It is also possible to delete / replace.
Hereinafter, other embodiments and modifications will be further described.

≪Number of switching elements≫
In FIG. 1A, the number of switching elements 21A and 21B in the primary side circuit body 11A and the secondary side circuit body 11B in the power conversion unit 100 has been illustrated and described, but the number is not limited to four. It may be composed of 3 or less or 5 or more. Further, the apparent number may be changed by connecting in parallel or in series depending on the wiring. Alternatively, a part of the switching element may be left unused without wiring.
Further, the open / close signal of some switching elements may be fixed at a predetermined potential and always used as an on (ON) state or an off (OFF) state.

≪Arrangement of switching elements≫
An example of the arrangement of the switching element is shown in FIGS. 1A and 2B. However, for convenience of explanation, these are schematically arranged. The arrangement is not limited to the above figure.
Further, as shown in FIG. 1A, the structure of the power conversion unit 100 including the switching element is shown to have a symmetrical shape with the center of the cooling path surface as the center line. This is because the symmetrical shape can reduce the variation in temperature rise in a plurality of switching elements.
However, when the bias in the operation of the switching element is taken into consideration, the arrangement may be asymmetrical without this limitation.

≪Switching element and semiconductor substrate≫
In the circuit configuration 810 of FIG. 12, semiconductor elements such as IGBTs (Insulated Gate Bipolar Transistors), IEGTs (Injection Enhanced Gate Transistors), MOSFETs (Metal-Oxide-Semiconductor Field Effect Transistors), and superjunction MOSFETs are used as switching elements. I explained that.
Further, the semiconductor substrate of the semiconductor element will be described. As the semiconductor element of the switching element, a semiconductor substrate such as GaN (gallium nitride), Si (silicon), or SiC (silicon carbide) is used.

<< Leakage detection sheet >>
FIG. 6 shows an example in which the liquid leakage detection sheet 53 is provided on the side surface of the dividing surface (joining surface) of the primary side unit 10A and the secondary side unit 10B. This is because, in the power conversion unit 300 shown in FIG. 6, since the divided surface is wide, if a liquid leak occurs in a part of the power conversion unit 300, the liquid leak can be detected on the entire surface of the divided surface.
However, it is also effective to apply a sheet to the entire surface of the divided surface on the safety side.

《Sound Listening Stick 55》
In FIG. 8, the sound listening rod 55 was attached to the joint (joint with a built-in liquid cooling tube) 61 of the power conversion unit (for example, the power conversion unit 100) to detect the leakage of the liquid refrigerant body. The listening rod 55 may be attached to the power conversion unit 300 of FIG. 6 provided with the above, and the power conversion unit may be provided with double detection means.
In this case, there is an effect that the leakage detection becomes more accurate.

《O-ring》
In FIG. 4A, the number of O-rings 52 is not limited to two. It may be one or three or more.
As shown in FIG. 4A, the liquid leakage sensor 51 is arranged between the two O-rings, but the arrangement is not limited to this. For example, due to structural restrictions, the liquid leakage sensor 51 may be provided at a location other than between the two O-rings.
Further, the shape in which the O-ring 52 is arranged is not limited to the circular shape. Depending on the structural restrictions and the shape and arrangement of the primary side circuit body 11A and the secondary side circuit body 11B, the primary side circuit body 11A may be arranged in a shape other than the circular shape.

《Copper plate and heat conductive layer》
In the fifth embodiment shown in FIG. 11, it has been described that the copper plate (first conductor) 91A is provided on the surface of the switching element (21A) on the cooling pipe 31 side. Further, it has been described that the copper plate (second conductor) 91B is provided on the surface of the switching element (21B) on the cooling pipe 31 side.
However, the first conductor (91A) and the second conductor (91B) may be a metal other than copper. For example, silver, aluminum, or an alloy having high thermal conductivity may be used.
As for the heat conductive layers 92A and 92B, an epoxy resin or a ceramic plate has been given as an example, but other materials may be used as long as they have good insulation and heat conductivity.
If the voltage difference between the copper plates 91A and 91B and the cooling pipe 31 is small and the silicone gels 23A and 23B have a withstand voltage, the heat conductive layers 92A and 92B can be omitted.

《Gel-like substance》
In FIGS. 1A and 4A, examples of filling the space of the primary side circuit body 11A and the secondary side circuit body 11B with the silicone gel are shown, but the present invention is not limited to the silicone gel. Another gel-like insulating substance may be used as a filling substance instead of the silicone gel.
There is also a method of adding another substance to the silicone gel.

《Dividable structural surface》
In the sixth embodiment shown in FIG. 9, the power conversion unit 200 shown in FIG. 4A has a structure in which the divisible structural surfaces 81A and 81B shown in FIG. 9 are provided. However, the basis is not limited to the power conversion unit 200. For example, the separable structural surfaces 81A and 81B may be provided for each of the power conversion units shown in FIGS. 1A, 6, 7, 10, and 11.

《Concave and convex structure of cooling pipe by cooling fins》
In the seventh embodiment shown in FIG. 10, the power conversion unit 200 shown in FIG. 4A has a structure in which the uneven structure of the cooling pipe 31 by the cooling fins 31B shown in FIG. 10 is provided. However, the basis is not limited to the power conversion unit 200. For example, each of the power conversion units shown in FIGS. 1A, 6, 7, 9, and 11 may be provided with an uneven structure of the cooling pipe 31 by the cooling fins 31B, respectively.

<< Configuration of cooling pipe and cooling path >>
In FIG. 1A, the cooling pipe 31 constituting the cooling passage 32 has been described as a configuration in which the upper and lower cooling pipes 31 are combined on the dividing surface (center line) 40, but the cooling pipes 31 are integrally formed to generate electric power. A method of inserting into the divided portion of the conversion unit 100 may be adopted. In this case, leakage of the cooling medium from the cooling pipe 31 can be reduced.

<< Structure with a copper plate and a heat conductive layer in the switching element >>
In the seventh embodiment shown in FIG. 11, the power conversion unit 200 shown in FIG. 4A has a structure in which the switching element shown in FIG. 11 has a copper plate and a heat conductive layer. However, the basis is not limited to the power conversion unit 200. For example, each power conversion unit shown in FIGS. 1A, 6, 7, 9, and 10 may be provided with a structure having a copper plate and a heat conductive layer in the switching element, respectively.

<< Other circuit configuration examples of power conversion unit and power conversion device >>
The circuit example of the power conversion unit is shown in FIGS. 12, 13, and 14, but is not limited thereto as described above. For example, if the number of switching elements of the primary circuit body 11A is set to 8, AC-DC conversion is performed by the rectifier circuit function with 4 switching elements, and the DC output is sent to the input terminals 12D1P and 12D1N in FIG. If input, a power conversion unit (power conversion device) having an AC-DC conversion function can be configured by the primary side circuit body 11A (8 switching elements) and the secondary side circuit body 11B.
Alternatively, the power conversion unit 1830 having the circuit configuration 830 having the conversion function of the AC-DC converter shown in FIG. 14 and the power conversion unit (100) having the circuit configuration 810 having the conversion function of the DC-DC converter shown in FIG. And can be combined to form a power conversion device that converts an AC voltage into a high DC voltage.

100,200,300,400,500,600,700,1810,1830 Power conversion unit (power conversion device)
1001A, 1001B, 1002A, 1002B In-panel frame 10A Primary side unit 10B Secondary side unit 11A Primary side circuit board 11B Secondary side circuit board 21A, 21B Switching element 22A Primary side circuit board 22B Secondary side circuit board 23A , 23B Silicone gel 24A Primary side housing 24B Secondary side housing 31 Cooling pipe 31B Cooling fin (cooling pipe protrusion)
32 Cooling path (liquid cooling path)
40 Divided surface (center line)
51 Leakage sensor (leakage detection means)
52 O-ring 53 Leakage detection sheet (leakage detection means)
54 IC tag type leak detector (leakage detection means)
55 Sound listening stick (leakage detection means)
56 Sound analysis unit 61 Fitting (joint with built-in liquid cooling tube)
62 Cooling pipeline (cooling pipe connection)
63, 64 Cooling pipeline 8000, 9000 Power converter 81A, 81B Dividable structural surface 810, 820, 830 Circuit configuration 91A First conductor (conductor, copper plate)
91B 2nd conductor (conductor, copper plate)
92A, 92B heat conductive layer

Claims (15)

1. A primary side unit including a primary side circuit body having a switching element and a circuit board, and a primary side housing for accommodating the primary side circuit body.
   A secondary side unit including a secondary side circuit body having a switching element and a circuit board, and a secondary side housing for accommodating the secondary side circuit body.
   A cooling path by a cooling pipe arranged between the primary side circuit body and the secondary side circuit body, and
   To prepare
   A power conversion unit characterized by that.
2. In claim 1,
   A liquid is used as a cooling medium in the cooling path, and the liquid is used.
   A liquid leakage detecting means for detecting leakage of the cooling medium is provided at a position where the primary side unit and the secondary side unit are in contact with each other.
   A power conversion unit characterized by that.
3. In claim 2,
   The liquid leakage detecting means is installed on the joint surface between the primary side unit and the secondary side unit.
   An O-ring is provided at the joint surface between the primary side unit and the secondary side unit.
   A power conversion unit characterized by that.
4. In claim 2,
   The liquid leakage detecting means is a liquid leakage detecting sheet that detects leakage of the cooling medium by discoloration of the sheet.
   A power conversion unit characterized by that.
5. In claim 2,
   The liquid leakage detecting means is an IC tag type liquid leakage detector that has a built-in IC and detects leakage of the cooling medium.
   A power conversion unit characterized by that.
6. In claim 4,
   The liquid leakage detecting means is a sound listening rod that detects leakage of the cooling medium by vibration.
   A power conversion unit characterized by that.
7. In claim 1,
   Inside the cooling path provided by the cooling pipe, the structure of the unevenness of the cooling pipe is provided.
   A power conversion unit characterized by that.
8. In claim 1,
   A plurality of grounded first conductors in contact with predetermined portions of the plurality of switching elements of the primary circuit body, respectively.
   A plurality of grounded second conductors, each of which is in contact with a predetermined portion of a plurality of switching elements of the secondary circuit body,
   With
   The cooling passage by the cooling pipe is arranged between the plurality of the first conductors and the plurality of the second conductors.
   A power conversion unit characterized by that.
9. In claim 8.
   A plurality of heat conductive layers composed of insulating members are provided between the plurality of the first conductors and the cooling pipes and between the plurality of the second conductors and the cooling pipes.
   A power conversion unit characterized by that.
10. In claim 1,
    A cooling pipe connecting portion for connecting to the cooling path is provided outside the primary side housing and the secondary side housing.
    The metal constituting the cooling pipe has a lower ionization tendency than the metal constituting the cooling pipe connection portion.
    A power conversion unit characterized by that.
11. In claim 1,
    The primary side circuit body and the space between the primary side housing and the primary side circuit body are filled with silicone gel and sealed.
    A silicone gel is filled and sealed between the secondary side circuit body and the secondary side housing and the secondary side circuit body.
    A power conversion unit characterized by that.
12. In claim 1,
    The inside of the primary side unit and the secondary side unit is composed of a solid, a liquid, or a gel, and there is no air region.
    A power conversion unit characterized by that.
13. In claim 1,
    The switching element is composed of an IGBT or MOSFET or IEGT.
    The semiconductor substrate constituting the switching element is made of GaN, Si, or SiC.
    A power conversion unit characterized by that.
14. A power conversion device comprising the power conversion unit according to any one of claims 1 to 12.
15. In claim 14,
    It has an in-panel frame as a power conversion device on the surface adjacent to multiple power conversion units.
    Insulating plates are provided between different in-panel frames of different power conversion units.
    A power conversion device characterized by the fact that.

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