CN114446643A

CN114446643A - Power conversion device

Info

Publication number: CN114446643A
Application number: CN202111275355.8A
Authority: CN
Inventors: 野野村昌也; 岸和田优; 渡边俊夫
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2020-11-05
Filing date: 2021-10-29
Publication date: 2022-05-06
Anticipated expiration: 2041-10-29
Also published as: JP6999777B1; CN114446643B; JP2022074617A

Abstract

The invention aims to realize the miniaturization of a power conversion device in a plane direction, restrain the deflection caused by vibration and improve the vibration resistance. A power conversion device (1) is provided with: a power module (20) mounted on a cooling surface (11) of the cooler (10); and a first capacitor (30a) and a second capacitor (30b) mounted on the C-surface (40a) and the S-surface (40b) of the printed circuit board (40), respectively. The first capacitor (30a) is of a type having a higher cooling requirement than the second capacitor (30 b). The printed board (40) is arranged with the C surface (40a) as one side of the cooling surface (11) and opposite to the cooling surface (11), and the first capacitor (30a) is thermally connected with the cooling surface (11). As a result, the area of the cooling surface (11) and the area of the printed circuit board (40) can be reduced as compared with the case where all the capacitors are thermally connected to the cooling surface (11).

Description

Power conversion device

Technical Field

The present application relates to a power conversion apparatus.

Background

A power conversion device generally includes a power module including switching elements for converting power or a module of the switching elements, and a smoothing capacitor for suppressing variation in a dc voltage input to the power module.

With the recent miniaturization and high output of power conversion devices, a cooling structure for efficiently dissipating heat from a power module to a cooler has been developed. On the other hand, the smoothing capacitor also has a large temperature rise due to its own heat generation or heat received from the power module, and thus needs to be cooled so as not to exceed the capacitor rated temperature. Therefore, a cooling structure capable of cooling not only the power module but also the smoothing capacitor is required.

As a cooling structure capable of cooling both the power module and the smoothing capacitor, for example, patent document 1 discloses a structure in which a capacitor module insertion portion is provided in a water channel case in which a refrigerant flow channel is formed, and semiconductor module insertion portions are provided on both sides of the capacitor module insertion portion.

Documents of the prior art

Patent document

Patent document 1: japanese patent No. 5247745

Disclosure of Invention

Technical problem to be solved by the invention

In recent years, in electric vehicles that have been frequently developed, there is an increasing demand for a highly durable power conversion device that has a higher output and is compact. In the demand for miniaturization, there is a case where a restriction is imposed on one planar direction, unlike the volume of the entire device. In the cooling structure as in patent document 1, since all the smoothing capacitors are disposed on the cooling surface, there is a problem that the device expands toward the cooling surface. In addition, there are problems as follows: since the cooling surface is enlarged, the deflection due to the vibration generated when the automobile is running is increased, and the device is easily damaged.

The present application discloses a technique for solving the above-described problems, and an object of the present application is to provide a power conversion device that is reduced in size in a planar direction, is suppressed in deflection due to vibration, and is improved in vibration resistance.

Means for solving the problems

The power conversion device according to the present application includes: a cooler having a coolant flow path and having at least one surface as a cooling surface; a power module mounted on the cooling surface; a printed board having two or more wiring layers on which wiring patterns are formed; and a capacitor mounted on the printed circuit board, the capacitor including a first capacitor and a second capacitor, the first capacitor being of a type having a higher cooling requirement than the second capacitor, the printed circuit board being disposed to face the cooling surface, the first capacitor being mounted on the first surface and thermally connected to the cooling surface, and the second capacitor being mounted on the second surface, when a surface of the printed circuit board on the cooling surface side is set as the first surface and a surface on the opposite side to the first surface is set as the second surface.

Effects of the invention

According to the power conversion device disclosed in the present application, the first capacitor and the second capacitor having different cooling requirements are included, and only the first capacitor having a higher cooling requirement is thermally connected to the cooling surface, so that the area of the cooling surface and the area of the printed circuit board can be reduced as compared with the case where all the capacitors are thermally connected to the cooling surface. Therefore, the performance diagram can be miniaturized in the planar direction, and the deflection due to vibration can be suppressed, thereby improving the vibration resistance.

Drawings

Fig. 1 is a diagram showing an example of a circuit of a power conversion device according to embodiment 1.

Fig. 2 is a plan view of the power conversion device according to embodiment 1.

Fig. 3 is a side sectional view of the power conversion device according to embodiment 1.

Fig. 4 is a front cross-sectional view of the power conversion device according to embodiment 1.

Fig. 5 is a diagram showing an example of a wiring pattern of a printed circuit board of the power conversion device according to embodiment 1.

Fig. 6 is a side sectional view of the power conversion device according to embodiment 2.

Fig. 7 is a front cross-sectional view of the power conversion device according to embodiment 2.

Fig. 8 is a three-dimensional view of a cooler of the power converter according to embodiment 2.

Fig. 9 is a front cross-sectional view of a power conversion device according to embodiment 3.

Fig. 10 is a three-dimensional view of a cooler of the power converter according to embodiment 3.

Fig. 11 is a front cross-sectional view of a power conversion device according to embodiment 4.

Fig. 12 is a side sectional view of the power conversion device according to embodiment 4.

Fig. 13 is a plan view of the power conversion device according to embodiment 5.

Fig. 14 is a front cross-sectional view of a power conversion device according to embodiment 5.

Fig. 15 is a plan view of the power conversion device according to embodiment 6.

Fig. 16 is a diagram illustrating a power conversion device according to embodiment 6.

Fig. 17 is a side sectional view of a power conversion device according to embodiment 6.

Fig. 18 is a front cross-sectional view of a power conversion device according to embodiment 6.

Fig. 19 is a diagram showing an example of the first-layer and fourth-layer wiring patterns of the printed circuit board of the power conversion device according to embodiment 6.

Fig. 20 is a diagram showing an example of the second-layer and third-layer wiring patterns of the printed circuit board of the power conversion device according to embodiment 6.

Fig. 21 is a diagram showing an example of the first-layer and sixth-layer wiring patterns of the printed circuit board of the power conversion device according to embodiment 7.

Fig. 22 is a diagram showing an example of the second layer and fifth layer wiring patterns of the printed circuit board of the power conversion device according to embodiment 7.

Fig. 23 is a diagram showing an example of the third-layer and fourth-layer wiring patterns of the printed circuit board of the power conversion device according to embodiment 7.

Fig. 24 is a plan view of a power conversion device according to embodiment 8.

Fig. 25 is a side sectional view of a power conversion device according to embodiment 8.

Fig. 26 is a front cross-sectional view of a power conversion device according to embodiment 8.

Detailed Description

Embodiment 1.

Next, a power conversion device according to embodiment 1 will be described with reference to the drawings. Fig. 1 is a diagram showing an example of a circuit of a power converter according to embodiment 1, fig. 2 is a plan view of the power converter according to embodiment 1, fig. 3 is a side sectional view of a portion shown in a-a in fig. 2 as viewed in the direction of an arrow, and fig. 3 is a front sectional view of a portion shown in B-B in fig. 2 as viewed in the direction of the arrow. Fig. 5 shows an example of a wiring pattern formed on a printed circuit board of the power conversion device according to embodiment 1. In the drawings, the same or corresponding portions are denoted by the same reference numerals.

The power conversion device 1 according to embodiment 1 is mounted on, for example, an electric vehicle, and includes an inverter circuit shown in fig. 1. The inverter circuit includes a power conversion unit 2, a power smoothing unit 3, P-side wirings 4a and N-side wirings 4b (collectively, wirings 4), and a control circuit unit 5.

The power converter 2 includes a power module 20 including a switching element 20 a. The power module 20 converts a direct current into an alternating current by switching the switching element 20a, and drives the motor 6 through an alternating current wiring. Further, an ac current generated in the motor 6 by a regenerative brake or the like is rectified by the ac wiring power module 20, smoothed by the smoothing capacitor 30, and stored in the battery 7.

The motor 6 for driving the electric vehicle is mostly driven by a full bridge circuit of a three-phase current type, and thus is composed of 3 power modules 20. The switching element 20a is, for example, a MOSFET (metal Oxide Semiconductor Field Effect Transistor) or an IGBT (Insulated Gate Bipolar Transistor).

The power smoothing unit 3 includes a smoothing capacitor 30 disposed at an input stage of the power conversion unit 2, and smoothes an input voltage of the battery 7, which is a lithium ion battery of several tens V to several hundreds V. The smoothing capacitor 30 smoothes an input voltage of the power module 20 that is likely to vibrate from the battery 7 through a long wiring or a pulse voltage generated by the motor 6 and rectified by the power module 20. The smoothing capacitor 30 is, for example, an aluminum electrolytic capacitor, a thin film capacitor, a ceramic capacitor, an electric double layer capacitor, or the like.

The control circuit unit 5 outputs an appropriate signal to the power module 20, and controls the switching of the power module 20 so as to obtain a target motor driving frequency and torque. The voltage of the control circuit unit 5 is usually 20V or less, and is often electrically insulated from the power module 20 to which several tens to several hundreds of V are applied.

The power module 20 and the smoothing capacitor 30 are electrically connected through the wiring 4. Since the wiring 4 often reaches a high temperature due to a large current flowing therethrough, a bus bar having a conductor exposed to the outside or a wiring pattern of the printed board 40 is used without using a cable with a coating. The wiring 4 includes a P-side wiring 4a which is electrically at the same potential as the high-voltage portion of the battery 7, and an N-side wiring 4b which is electrically at the same potential as the low-voltage portion of the battery 7. The material of the wiring 4 is selected from metals including copper, aluminum, tin, gold, silver, iron, an alloy thereof, and a nickel alloy, for example.

In the power conversion device 1 shown in fig. 1, the smoothing capacitor 30 has a temperature rise due to joule heat generated by its own Equivalent Series Resistance (hereinafter, referred to as ESR) and heat received from the wiring 4 and the power supply module 20. Therefore, the smoothing capacitor 30 is required not to exceed the rated temperature.

The cooler 10, the power module 20, the printed circuit board 40, and the smoothing capacitor 30 constituting the power conversion device 1 will be described in detail with reference to fig. 2 to 5. As shown in fig. 3, the cooler 10 has a refrigerant passage 12 through which a refrigerant 13 passes, and the refrigerant 13 flows in from the outside of the power conversion device 1 through a passage inlet 12a and flows out to the outside of the power conversion device 1 through a passage outlet 12 b. For the refrigerant 13, a liquid such as water or ethylene glycol, or a gas such as a fluorocarbon, propane, propylene, butane, carbon dioxide, or ammonia is used.

At least one surface of the cooler 10 is formed as a cooling surface 11. Cooling surface 11 is formed by making the thermal resistance from cooling surface 11 to coolant flow passage 12 smaller than the thermal resistance from the other surface of cooler 10 to coolant flow passage 12. Specifically, the thickness of the structure from the cooling surface 11 to the coolant flow passage 12 is reduced, and the heat conductivity is increased by providing the structure from the cooling surface 11 to the coolant flow passage 12 with a material having high heat conductivity, or by providing fins in the coolant flow passage 12 on the cooling surface 11 side.

The material of the cooler 10 is selected from aluminum, copper, tin, gold, silver, iron, an alloy containing these metals, a metal such as a nickel alloy, a ceramic such as aluminum nitride and silicon carbide, a carbon-based composite material, and the like. The cooler 10 is, for example, configured to be separable into an upper portion and a lower portion on a plane including a lower surface of the refrigerant flow path 12.

As a molding method of the cooler 10, in addition to extrusion molding using a die, there are a method of pouring a liquid material into a die and solidifying, a method of cutting out a lump material, and the like. After the upper and lower portions are formed, the upper and lower portions are fixed to each other by screwing, welding, or adhesion, including the flow path inlet 12a and the flow path outlet 12 b. Alternatively, the modeling may be performed using a device such as a 3D printer.

The power module 20 includes terminals such as a P-side terminal 21a, an N-side terminal 21b, an ac terminal 23 connected to an ac wiring, and a signal terminal 22 connected to an inverter control unit. The power module 20 is mounted on the cooling surface 11 of the cooler 10, and is fixed to the cooler 10 by a pressing spring, a screw stopper, or the like. TIM (Thermal Interface Material), heat-dissipating lubricating oil, adhesive having high Thermal conductivity, and the like are disposed between the power module 20 and the cooling surface 11 as necessary.

The printed circuit board 40 has two or more wiring layers on which wiring patterns such as a P-side wiring pattern 41a and an N-side wiring pattern 41b are formed, and has two layers of a C-side 40a and an S-side 40b in embodiment 1. The wiring pattern is made of, for example, copper, silver, gold, tin, nickel, or the like. The material of the printed board 40 is, for example, paper phenol, paper epoxy glass composite, glass epoxy, polyimide, metal, or the like.

The capacitor mounted on the printed circuit board 40 is the smoothing capacitor 30 and includes a first capacitor 30a and a second capacitor 30 b. Further, when it is not necessary to particularly distinguish them, they are collectively referred to as the smoothing capacitor 30. The first capacitor 30a is of a kind whose cooling requirement is higher than that of the second capacitor 30 b.

The printed circuit board 40 is disposed to face the cooling surface 11 of the cooler 10. In embodiment 1, the printed circuit board 40 and the cooling surface 11 are disposed to face each other with the spacer 14 interposed therebetween. When the surface of the printed circuit board 40 on the cooling surface 11 side is a first surface and the surface on the opposite side to the first surface is a second surface, the first capacitor 30a is mounted on the first surface (i.e., the C surface 40a) and thermally connected to the cooling surface 11, and the second capacitor 30b is mounted on the second surface (i.e., the S surface 40 b).

In addition, the thermal connection refers to a state in which two objects are in direct contact or in contact through a heat conductive member (see fig. 14). That is, the heat conductive member may be disposed between the first capacitor 30a and the cooling surface 11. The thermal conductivity of the heat conductive member is 0.1W/(mK) or more, preferably 1.0W/(mK) or more, and more preferably 10.0W/(mK) or more.

Examples of the heat conductive member include TIM, heat dissipating lubricating oil, adhesive, potting, and the like, and the material thereof is a resin such as silicon, epoxy, urethane, and acrylic. The heat conductive member has elasticity or thermosetting properties, and is preferably embedded without a gap between the two objects. In addition, the heat conductive member preferably has insulation properties.

The printed substrate 40 is fixed to the cooler 10 by a plurality of fixing mechanisms. In embodiment 1, the fixing mechanism is the spacer 14 and the screw 15. The spacer 14 is fixed to the cooler 10, and the screws 15 are fixed to screw holes (not shown) formed in the spacer 14. The thermal conductivity of the spacer 14 and the screw 15 is 0.1W/(m · K) or more, preferably 1.0W/(m · K) or more, and more preferably 10.0W/(m · K) or more. Thereby, the heat of the printed circuit board 40 is transferred to the cooler 10 via the spacer 14 and the screws 15.

The material of the spacer 14 and the screw 15 is selected from, for example, aluminum, copper, tin, gold, silver, iron, an alloy containing these, a metal such AS a nickel alloy, a ceramic such AS aluminum nitride and silicon carbide, a resin such AS engineering plastic (for example, PC, POM, PA, PET, AS), and super engineering plastic (for example, PEEK, PPS, PTFE, PES), and the like. The spacer 14 and the screw 15 may be made of the same material or different materials.

In embodiment 1, as shown in fig. 2, a plurality of screws 15 are provided on the peripheral edge portion of the printed board 40, and one screw 15 is provided at a place other than the peripheral edge portion of the printed board 40. Further, a plurality of screws 15 may be provided outside the peripheral edge portion of the printed board 40, or may not be provided in the central portion of the printed board 40.

The fixing means for fixing the printed circuit board 40 to the cooler 10 is not limited to the screw 15, and may be adhesion using an adhesive, welding or caulking to a metal portion of the printed circuit board 40, or the like. In either case, at least one of the fixing mechanisms is preferably disposed at a position other than the peripheral edge portion of the printed board 40.

The first capacitor 30a and the second capacitor 30b may be one capacitor or may include a plurality of capacitors. The first capacitor 30a and the second capacitor 30b have a total capacity of about 1 μ F to 100mF, and preferably 0.1 μ F or more per capacitor.

The first capacitor 30a is a type of capacitor whose cooling requirement is higher than that of the second capacitor 30b, and needs to be cooled more aggressively than the second capacitor 30 b. Since the first capacitor 30a is thermally connected to the cooling surface 11, it is cooled more actively than the second capacitor 30 b. The second capacitor 30b is cooled by using the printed substrate 40, the screws 15, the spacers 14, and the first capacitor 30a as a heat conduction path to the cooler 10.

When the difference in the cooling requirements of the first capacitor 30a and the second capacitor 30b is caused by the difference in the heat generation amounts thereof, the heat generation amount of the first capacitor 30a is larger than that of the second capacitor 30 b. In addition, when the difference in the amount of heat generation is caused by the difference in the capacitances thereof, the capacitance of the first capacitor 30a is larger than that of the second capacitor 30 b.

When the capacitance of the first capacitor 30a is C1 and the capacitance of the second capacitor 30b is C2, the relationship of C2< C1 holds. Further, since the impedance Z of the ideal capacitor is represented by Z ═ 1/ω C (ω: angular frequency), Z1< Z2 holds for the impedance Z1 of the first capacitor 30a and the impedance Z2 of the second capacitor 30 b.

Further, according to the above-described relationship of the impedances, when power is supplied from the battery 7 to the smoothing capacitor 30 or to the motor 6, I2< I1 holds for the current I1 flowing through the first capacitor 30a and the current I2 flowing through the second capacitor 30 b. When the ESR levels of the first capacitor 30a and the second capacitor 30b are the same, P2 < P1 holds for the heat generation P1 generated by the first capacitor 30a and the heat generation P2 generated by the second capacitor 30 b. Therefore, the temperature rise of the first capacitor 30a is larger than the temperature rise of the second capacitor 30 b.

In addition, in the case where the difference in the amounts of heat generation is due to the difference in the dielectric tangents thereof, the dielectric tangent of the first capacitor 30a is larger than that of the second capacitor 30 b. When the dielectric tangent of the first capacitor 30a is tan δ 1 and the dielectric tangent of the second capacitor 30b is tan δ 2, the relationship of tan δ 2< tan δ 1 holds. Since the dielectric tangent is an index indicating a ratio of the capacitance C to the ESR of the capacitor, when the ESR of the first capacitor 30a is ESR1 and the ESR of the second capacitor 30b is ESR2, ESR 2< ESR1 is satisfied under the condition that C1 is equal to C2. At this time, if I1 is I2, P2 < P1 is established. Therefore, the temperature rise of the first capacitor 30a is larger than the temperature rise of the second capacitor 30 b.

In addition, in the case where the difference in the cooling requirements of the first capacitor 30a and the second capacitor 30b is due to their lifetimes, there is a difference in the lifetimes of the first capacitor 30a and the second capacitor 30b when used under the same conditions. For example, L1 < L2 is established when the lifetime of the first capacitor 30a at an arbitrary temperature is L1 and the lifetime of the second capacitor 30b is L2. However, since the difference between the rated temperature and the actual capacitor temperature (longer life as larger) and the difference between the actual capacitor temperature and the ambient temperature (shorter life as larger) affect the life of the capacitor, the capacitor 30a having a longer life when used under the same conditions may be used as the first capacitor 30 a. In either case, by mounting the first capacitor 30a on the C-surface 40a and thermally connecting the same to the cooling surface 11, and mounting the second capacitor 30b on the S-surface 40b, the difference in the life of the first capacitor 30a and the second capacitor 30b becomes smaller than the difference in the life when used under the same conditions.

The printed board 40 in embodiment 1 is composed of two layers, and fig. 5(a) shows an example of a wiring pattern on the S-side, and fig. 5(b) shows an example of a wiring pattern on the C-side. In addition, in these figures, for easy understanding of the wiring pattern, a wiring pattern of a portion overlapping with the smoothing capacitor 30 is also shown. The P-side wiring pattern 41a and the N-side wiring pattern 41b on the S-plane and the C-plane are preferably symmetrical in shape except for the portion where the through hole 42 for electrically connecting the layers is formed or the periphery thereof.

The printed circuit board 40 has a connection portion 44 electrically connected to the power module 20, and also has a wiring pattern electrically connecting the connection portion 44 and the smoothing capacitor 30. The P-side terminal 21a and the N-side terminal 21b of the power module 20 are electrically connected to the P-side wiring pattern 41a and the N-side wiring pattern 41b, respectively, via the connection portion 44.

The smoothing capacitor 30 is electrically connected to the P-side wiring pattern 41a and the N-side wiring pattern 41b via the capacitor terminal 31. The capacitor terminal 31 may have a straight shape such as to be inserted into a through hole of the printed board 40, or may have a curved shape such as to be connected to a pattern of the printed board 40 by surface mounting.

The connection portion 44 is a through hole into which the P-side terminal 21a and the N-side terminal 21b provided in the power module 20 can be inserted, a metal fitting attached to the printed circuit board 40, or the like. The terminal and the metal fitting are fixed and connected by fastening with a screw 15, welding, adhesion using a conductive adhesive, or the like.

When the connection portion 44 is not formed on the printed board 40, a wiring member such as a bus bar or a wire harness electrically connected to the P-side wiring pattern 41a and the N-side wiring pattern 41b is mounted on the printed board 40. These wiring members are connected to the terminals directly or via other conductive structures.

According to the power conversion device 1 of embodiment 1 configured as described above, by providing the first capacitor 30a and the second capacitor 30b having different cooling requirements, and mounting the first capacitor 30a having a higher cooling requirement on the C-surface 40a of the printed circuit board 40 and thermally connecting the same to the cooling surface 11 of the cooler 10, the area of the cooling surface 11 and the area of the printed circuit board 40 can be reduced as compared with the case where all the smoothing capacitors 30 are thermally connected to the cooling surface 11.

Further, by using the first capacitor 30a and the second capacitor 30b having different heat generation amounts and actively cooling the first capacitor 30a having a larger heat generation amount than the second capacitor 30b having a smaller heat generation amount, a temperature difference between them can be suppressed and more efficient cooling can be performed.

As a comparative example, when capacitors having the same amount of heat generation are disposed on the C surface 40a and the S surface 40b of the printed circuit board 40, it is necessary to overcool the capacitor on the C surface 40a side so that the capacitor mounted on the S surface 40b does not exceed the rated temperature.

Further, by using the first capacitor 30a and the second capacitor 30b having different specifications such as capacitance and dielectric tangent, the degree of freedom in design with respect to the size and cost of the entire device is improved as compared with the case of using only the same type of capacitor.

In addition, by using the first capacitor 30a and the second capacitor 30b which have differences in life span when used under the same conditions, and actively cooling the first capacitor 30a as compared with the second capacitor 30b, it is possible to reduce the difference in life span therebetween. This increases the total capacitance of the capacitors over the same number of years, and thus a capacitor having a small initial capacitor capacitance can be selected. In general, the smaller the capacitor capacitance, the smaller the capacitor size, and therefore the area of the cooling surface 11 and the area of the printed board 40 can be reduced.

As another comparative example, when capacitors having the same degree of life are disposed on the C-side 40a and the S-side 40b of the printed circuit board 40, the life of the capacitor mounted on the S-side 40b is shorter than that of the capacitor mounted on the C-side 40a, and therefore, it is necessary to design the capacitors according to the capacitors mounted on the S-side 40 b.

Further, by disposing the heat conductive member between the first capacitor 30a and the cooling surface 11, the cooling effect for the first capacitor 30a is improved, and the cooling effect for the printed circuit board 40 and the second capacitor 30b having the first capacitor 30a as the heat conductive path is also improved. This allows the smoothing capacitors 30 to be arranged more densely, and the printed circuit board 40 to be further downsized.

In addition, since the P-side wiring pattern 41a and the N-side wiring pattern 41b formed on the printed board 40 face each other between the layers, inductance generated by these wiring patterns can be reduced. This can reduce the switching loss of the power module 20 and reduce the amount of heat received by the smoothing capacitor 30 from the power module 20.

Further, since the printed board 40 has the connection portion 44, it is not necessary to provide a wiring member such as a bus bar for electrically connecting the smoothing capacitor 30 and the power module 20, a terminal portion for connecting the wiring member and the printed board 40, or a structure such as a terminal portion for connecting the wiring member and the power module 20.

Therefore, the amount of heat received by the smoothing capacitor 30 due to heat generation caused by wiring resistance existing in the structure and current flowing through the structure can be reduced as compared with the case of using these structures. Further, since the wiring inductance can be reduced as compared with the case of having the above-described structure, the switching loss of the power module 20 can be reduced, and the amount of heat received by the smoothing capacitor 30 can be reduced.

Further, by fixing the printed circuit board 40 to the cooler 10 by the spacer 14 and the screws 15, the second capacitor 30b and the printed circuit board 40 have a heat conduction path to the cooler 10 in addition to cooling by the surrounding gas phase, and therefore the temperature rise is reduced. This can further increase the characteristic difference between the first capacitor 30a and the second capacitor 30 b. In addition, the number of first capacitors 30a can be reduced and the number of second capacitors 30b can be increased, thereby improving the degree of freedom in design with respect to the size or cost of the entire device.

Further, by forming the spacer 14 of a material having high thermal conductivity such as copper and integrating it with the cooler 10 by soldering or the like, the thermal resistance can be further reduced, and the temperature rise of the second capacitor 30b and the printed circuit board 40 can be further reduced. This makes it easier for the heat of the first capacitor 30a to be transferred to the printed circuit board 40 and the second capacitor 30b, and the temperature rise of the first capacitor 30a can be further reduced.

Further, by providing the screws 15 for fixing the printed circuit board 40 to the cooler 10 at a portion other than the peripheral portion of the printed circuit board 40, a heat conduction path to the cooler 10 is formed at a portion other than the peripheral portion of the printed circuit board 40, and therefore, the temperature rise of the smoothing capacitor 30 mounted in the vicinity of the central portion of the printed circuit board 40 can be reduced.

As described above, according to embodiment 1, in addition to the arrangement of the first capacitor 30a and the second capacitor 30b, the arrangement and material of the screw 15 and the spacer 14, and the wiring pattern of the printed circuit board 40 and the connection portion 44 are devised, whereby the temperature rise of the smoothing capacitor 30 can be reduced. This allows smoothing capacitors 30 to be arranged more densely, and the area of cooling surface 11 and the area of printed circuit board 40 to be further reduced.

Further, by reducing the size of the printed circuit board 40, when the power conversion device 1 vibrates, the bending stress generated in the printed circuit board 40 is reduced, and the printed circuit board 40 is less likely to be damaged. By fixing the portion other than the peripheral portion of the printed board 40 with the screws 15, the printed board 40 can be further suppressed from being deflected by vibration. This realizes a reduction in size of the power conversion device 1 in the planar direction and improves vibration resistance.

Embodiment 2.

Since the plan view of the power conversion device according to embodiment 2 is the same as that of embodiment 1, fig. 2 is used. Fig. 6 and 7 show a power conversion device according to embodiment 2, fig. 6 is a side sectional view of a portion shown in a-a in fig. 2 viewed from the direction of an arrow, and fig. 7 is a front sectional view of a portion shown in B-B in fig. 2 viewed from the direction of the arrow. Fig. 8 is a three-side view of a cooler according to embodiment 2.

The cooler 10 of the power conversion device according to embodiment 2 includes a concave portion 16 formed on a cooling surface. In embodiment 2, there is one recess 16, but a plurality of recesses 16 may be provided. As shown in fig. 7, the side wall 16a of the recess 16 is preferably integrally molded with the cooler 10.

The cooler 10 has a second cooling surface 11b as the bottom of the recess 16 and a third cooling surface 11c as the top of the side wall portion 16a of the recess 16. In the following description, the portion where the power module 20 is mounted is referred to as a first cooling surface 11a, and the first cooling surface 11a, a second cooling surface 11b, and a third cooling surface 11c are collectively referred to as cooling surfaces.

As shown in fig. 7, the printed circuit board 40 is fixed to the third cooling surface 11c by screws 15 and is thermally connected to the third cooling surface 11 c. The first capacitor 30a is disposed inside the recess 16 and thermally connected to the second cooling surface 11 b.

When the plurality of first capacitors 30a are disposed inside the concave portion 16, a part or all of them are thermally connected to the second cooling surface 11b and the side surface of the side wall portion 16 a. In embodiment 2, as shown in fig. 7, the first capacitor 30a disposed at one end of the recess 16 is in contact with the side surface of the side wall portion 16 a. Further, an insulating heat conductive member may be disposed between the first capacitor 30a and the second cooling surface 11b and between the first capacitor 30a and the side wall portion 16 a.

When the direction perpendicular to the cooling surface of the cooler 10 is taken as the height direction, the C-surface 40a of the printed circuit board 40 and the second cooling surface 11b are separated by only a distance substantially equal to the height dimension of the first capacitor 30 a. The C-surface 40a of the printed circuit board 40 is spaced apart from the first cooling surface 11a by a distance substantially equal to the height of the power module 20, or by a distance of several millimeters in addition to the height.

The height of the side wall portion 16a is substantially the same as the height of the first capacitor 30a, which is the distance from the second cooling surface 11b to the C-surface 40a of the printed circuit board 40. The printed circuit board 40 is fixed to the third cooling surface 11c by a plurality of screws 15. As shown in fig. 8, cylindrical screw stoppers 16c are provided at two locations inside the recess 16. This allows three sides of the peripheral edge of the printed circuit board 40 and other portions to be fixed to the cooler 10. The other structures are the same as those of embodiment 1, and therefore, the description thereof is omitted here.

According to the power conversion device of embodiment 2, by disposing the first capacitor 30a inside the concave portion 16 formed in the cooling surface 11 of the cooler 10, a part of the first capacitor 30a is thermally connected to the side wall portion 16a of the concave portion 16, and the first capacitor 30a can be cooled more efficiently.

Further, since the height of the first cooling surface 11a on which the power module 20 is mounted is different from the height of the second cooling surface 11b on which the first capacitor 30a is disposed, the power module 20 is spaced apart from the first capacitor 30a, and therefore, heat generated by the power module 20 is not easily transmitted to the first capacitor 30 a. Therefore, the temperature rise of the first capacitor 30a can be further reduced as compared with embodiment 1. Further, since the distance between the bottom surface of the cooler 10 and the upper surface of the second capacitor 30b is shorter than that in embodiment 1, the dimension in the height direction can be reduced as well as the dimension in the plane direction.

Further, since the distance from the power module 20 to the printed board 40 can be set to 0 to several millimeters, the P-side terminal 21a and the N-side terminal 21b can be shortened as compared with embodiment 1, and the wiring inductance generated by each terminal can be reduced. Thereby, the switching loss in the power module 20 can be reduced, and the temperature rise of the smoothing capacitor 30 due to the temperature rise of the power module 20 and the heat received from the power module 20 can be reduced. Therefore, the areas of the first cooling surface 11a and the second cooling surface 11b can be reduced. In addition, since the terminal is shortened, folding of the terminal due to vibration can be reduced.

Further, since the printed circuit board 40 and the third cooling surface 11c are directly fixed by the screws 15, the thermal resistance is reduced as compared with the case of passing through the spacers 14, and the heat of the printed circuit board 40 and the second capacitor 30b is easily transmitted to the cooler 10. This can further reduce the temperature rise of the printed circuit board 40 and the second capacitor 30 b. Further, by fixing the printed circuit board 40 to the third cooling surface 11c, compared with the case of fixing to the spacer 14, flexure due to vibration is suppressed, and vibration resistance is improved.

Thus, according to embodiment 2, in addition to the same effects as embodiment 1, the temperature rises of the smoothing capacitor 30 and the power module 20 can be further reduced compared to embodiment 1, and therefore, they can be arranged more densely. This reduces the area of the printed circuit board 40 and the area of the cooling surface of the cooler 10, thereby achieving a reduction in the size of the power conversion device in the planar direction and the height direction and improving vibration resistance.

Embodiment 3.

Since the plan view of the power conversion device according to embodiment 3 is the same as that of embodiment 1, fig. 2 is used. Fig. 9 is a front cross-sectional view of a portion B-B in fig. 2, viewed from the direction of the arrows, showing a power converter according to embodiment 3. Fig. 10 is a three-side view of a cooler according to embodiment 3. The power conversion device according to embodiment 3 is the same as that of embodiment 2 described above in side sectional view (see fig. 6).

The cooler 10 of the power conversion device according to embodiment 3 has a plurality of concave portions 16 on the cooling surface thereof, and the concave portions 16 extend in the flow direction of the refrigerant 13. The plurality of first capacitors 30a are arranged in the flow direction of the refrigerant 13, and are housed in the concave portion 16 in respective rows. Thereby, all the first capacitors 30a are thermally connected to the second cooling surface 11b and the side surfaces of the side wall portions 16a directly or via an insulating heat transfer member.

In embodiment 3, the screws 15 provided in the portions other than the peripheral portion of the printed circuit board 40 are fixed to the third cooling surface 11c other than the end portion of the cooler 10. Since other configurations are the same as those in embodiments 1 and 2, descriptions thereof are omitted here.

According to the power conversion device of embodiment 3, in addition to the same effects as those of embodiments 1 and 2 described above, the first capacitors 30a mounted on the inner side of the printed circuit board 40 can be cooled by the side wall portions 16a of the concave portions 16, so that the cooling effect of all the first capacitors 30a can be improved, and the temperature rise of the first capacitors 30a can be further reduced.

Further, since the area of the third cooling surface 11c thermally connected to the printed circuit board 40 is increased as compared with embodiment 2, heat of the printed circuit board 40 and the second capacitor 30b is more easily transferred to the cooler 10 than in embodiment 2. This can further reduce the temperature rise of the printed circuit board 40 and the second capacitor 30 b. This allows the smoothing capacitors 30 to be arranged more densely, reduces the area of the printed circuit board 40, and improves the vibration resistance.

Further, since the portions other than the peripheral portion of the printed board 40 can be fixed by the third cooling surface 11c and the screws 15, the printed board 40 can be reduced in deflection due to temperature rise. Therefore, the state in which the first capacitor 30a mounted on the inner side of the printed circuit board 40 is thermally connected to the second cooling surface 11b can be ensured and maintained. Therefore, the reliability of cooling the first capacitor 30a is improved.

Further, it is possible to prevent the mounted components of the printed circuit board 40 and the printed circuit board 40 from being damaged due to thermal stress in the thermal cycle during operation and stoppage of the circuit. Similarly, damage to components mounted on the printed circuit board 40 or the printed circuit board 40 due to external vibration can be prevented, and durability and vibration resistance of the printed circuit board 40 can be improved.

Embodiment 4.

Since the plan view of the power conversion device according to embodiment 4 is the same as that of embodiment 1, fig. 2 is used. Fig. 11 and 12 show a power conversion device according to embodiment 4, fig. 11 is a front sectional view of a portion shown in B-B of fig. 2 as viewed in the direction of the arrow, and fig. 12 is a side sectional view of a portion shown in C-C of fig. 11 as viewed in the direction of the arrow.

The cooler 10 of the power conversion device according to embodiment 4 includes a plurality of concave portions 16, and a side wall channel 12c as a refrigerant channel is provided inside a side wall portion 16a of the concave portion 16. Thus, the refrigerant 13 flows through the side wall portion 16a, and the cooling effect of the third cooling surface 11c and the side surface of the side wall portion 16a is further improved as compared with the above embodiment 3. Since the other structures are the same as those of embodiment 3, the description thereof is omitted here.

According to embodiment 4, in addition to the same effects as those of embodiment 3, the cooling effect of the smoothing capacitor 30 and the printed circuit board 40 can be further improved as compared with embodiment 3, and the temperature rise thereof can be reduced.

Embodiment 5.

Fig. 13 is a plan view of the power conversion device according to embodiment 5, and fig. 14 is a front cross-sectional view of a portion shown by D-D in fig. 13 as viewed in the direction of the arrows. The power conversion device according to embodiment 5 is the same as that of embodiment 4 described above in side sectional view (see fig. 12).

The cooler 10 of the power conversion device according to embodiment 5 includes a plurality of concave portions 16 and side wall channels 12c, as in embodiment 4. The positional relationship between the first capacitor 30a and the second capacitor 30b and the positional relationship between the through hole 42 formed in the printed circuit board 40 are different from those in embodiment 4. Since the other structures are the same as those in embodiment 4, the description thereof is omitted here.

In the plan view of fig. 13, the first capacitor 30a mounted on the rear surface of the printed circuit board 40 is shown by a broken line. As shown in fig. 13, the first capacitor 30a and the second capacitor 30b are disposed at positions that do not overlap with the cooling surface of the cooler 10 in the vertical direction. As shown in fig. 14, the second capacitor 30b is disposed to face the third cooling surface 11c with the printed board 40 interposed therebetween.

A heat conductive member 50 is disposed at least partially between the third cooling surface 11c and the printed board 40, and the printed board 40 and the third cooling surface 11c are thermally connected by the heat conductive member 50. The heat conductive member 50 preferably has elasticity, and when insulation is required between the wiring of the printed circuit board 40 and the cooler 10, an insulating member is used.

The printed board 40 has a through hole 42 for electrically connecting the layers at a position facing the third cooling surface 11c via the heat conductive member 50. The through-holes 42 are preferably conductive paths electrically connecting the P-side wiring patterns 41a or the N-side wiring patterns 41b formed on the C-side, S-side, or inner layer of the printed board 40. When the temperature of the first capacitor 30a is lower than that of the second capacitor 30b, it is preferable to dispose a part of the hole 42 within 10mm of the periphery of the second capacitor 30b as much as possible. However, the configuration of the through-hole 42 is not limited thereto.

Although the requirement for cooling the second capacitor 30b is lower than that of the first capacitor 30a, the temperature rise is not so small depending on the heat received from the first capacitor 30a, the wiring pattern, the power module 20, the atmospheric temperature, and the like, in addition to the self-heat generation. Similarly, the printed board 40 also has a temperature rise due to self-heating in the wiring pattern. In particular, in a power converter that handles a large current, the wiring pattern of the printed circuit board 40 on which the current is concentrated may be higher in temperature than the smoothing capacitor 30 that can distribute the current by increasing the number of parallel capacitors. Therefore, a means for reducing the temperature rise of the second capacitor 30b and the printed circuit board 40 may be necessary.

In embodiment 5, since the first capacitor 30a and the second capacitor 30b are disposed so as not to overlap the cooling surface of the cooler 10 in the vertical direction, the amount of heat received by the second capacitor 30b from the first capacitor 30a can be reduced. Therefore, the temperature rise of the second capacitor 30b due to the first capacitor 30a can be reduced.

Further, since the second capacitor 30b is disposed to face the third cooling surface 11c via the printed board 40, heat of the second capacitor 30b is easily transferred to the cooler 10. Further, by disposing the heat conductive member 50 between the printed circuit board 40 and the third cooling surface 11c, the printed circuit board 40 can be more reliably thermally connected to the third cooling surface 11c, and the cooling effect can be improved.

Further, since the temperature rise of the second capacitor 30b can be reduced, the capacitance or number of the second capacitors 30b can be increased, and the capacitance or number of the first capacitors 30a can be decreased. Further, by using the heat conductive member 50 having elasticity, the vibration of the printed circuit board 40 can be reduced, and the vibration resistance can be improved.

Further, since the heat of the wiring pattern, particularly the inner side of the printed circuit board 40, can be transmitted to the third cooling surface 11c via the conductive member 50, the heat transmitted from the printed circuit board 40 to the first capacitor 30a can be reduced, and as a result, the temperature rise of the first capacitor 30a can be reduced.

Further, by providing the through hole 42 in the printed circuit board 40, heat transfer through the through hole 42 can be performed, and the effect of equalizing the temperatures of the C-plane and the S-plane, or the first capacitor 30a and the second capacitor 30b can be obtained. In particular, the cooling effect on the first capacitor 30a is sufficiently good, and when the temperature of the first capacitor 30a is lower than that of the second capacitor 30b, there is a heat conduction path through which the heat of the second capacitor 30b is transferred from the S-surface to the C-surface, the first capacitor 30a, and the cooler 10 via the through hole 42, and the second capacitor 30b can be efficiently cooled.

According to embodiment 5, in addition to the same effects as those of embodiment 4, the cooling effect of the second capacitor 30b and the printed circuit board 40 can be further improved as compared with embodiment 4, and the temperature rise thereof can be reduced.

Embodiment 6.

Fig. 15 is a plan view of the power converter according to embodiment 6, fig. 16 is a plan view of fig. 15 with the printed circuit board removed, fig. 17 is a side sectional view of a portion shown in E-E of fig. 15 viewed in the direction of the arrow, and fig. 18 is a front sectional view of a portion shown in F-F of fig. 15 viewed in the direction of the arrow. Fig. 19 and 20 show an example of a wiring pattern formed on a printed circuit board of the power conversion device according to embodiment 6.

As shown in fig. 15, in the power conversion apparatus according to embodiment 6, most of the cooling surface of the cooler 10 is covered with the printed circuit board 40. When the printed board 40 is removed, as shown in fig. 16, a plurality of concave portions 16 are formed in the cooler 10. The second cooling surface 11b, which is the bottom of the plurality of concave portions 16, is rectangular, and the long sides of the rectangle are arranged to face each other, thereby forming a plurality of elongated third cooling surfaces 11 c.

The power module 20 includes a switching element 20a constituting a three-phase ac inverter circuit. In embodiment 6, one power module 20 includes 2 switching elements 20a, which correspond to the upper arm and the lower arm of the bridge circuit section in the inverter circuit diagram shown in fig. 1. By using three such power modules 20, the power conversion unit 2 of the three-phase ac inverter is configured.

The plurality of power modules 20 constituting the U-phase, the V-phase, and the W-phase are arranged with their long sides facing each other, and a plurality of recesses 16 extending in the longitudinal direction of the power modules 20 are formed adjacent to the power modules 20. In embodiment 6, the top of the side wall portion 16a of the recess 16 is the third cooling surface 11c and is also the first cooling surface 11a on which the power module 20 is mounted.

The first capacitors 30a housed in the recess 16 are arranged in the longitudinal direction of the power module 20. The number of first capacitors 30a housed in each recess 16, that is, the number of first capacitors 30a adjacent to each power module 20 is preferably equal. Although the arrangement of the second capacitors 30b is not particularly limited, it is preferable that the number of the power modules 20 and the second capacitors 30b adjacent to each other through the printed substrate 40 be equal to each other.

A distance for ensuring insulation between the printed board 40 and the power module 20 is required, but the P-side terminal 21a and the N-side terminal 21b are preferably close to each other by a distance of about 0.5mm to 20mm in order to prevent the P-side terminal 21a and the N-side terminal 21b from becoming excessively long. The upper surface of the power module 20 may be a heat radiation surface other than the terminal portion, and the printed circuit board 40 and the heat radiation surface of the power module 20 may be in contact with each other with an insulating heat conductive member interposed therebetween.

As shown in fig. 15, the printed board 40 is formed with a long hole 45 for passing the signal terminal 22 and the ac terminal 23 extending from the power module 20. Among them, there is also a method of connecting the control circuit unit 5 or the motor 6 to the power module 20 via a connector or the like mounted on the printed circuit board 40. In this case, a through hole having a side surface plated with gold such as copper is formed in the printed board 40, and the signal terminal 22 or the ac terminal 23 is electrically connected and fixed by soldering, welding, or the like.

The printed substrate 40 in embodiment 6 is configured of four layers, and fig. 19 (a) shows an example of a wiring pattern of a first layer, fig. 19 (b) shows an example of a wiring pattern of a fourth layer, fig. 20 (a) shows an example of a wiring pattern of a second layer, and fig. 20 (b) shows an example of a wiring pattern of a third layer. In the same manner, the P-side wiring pattern 41a and the N-side wiring pattern 41b are formed on the first layer (S-side) on which the second capacitor 30b is mounted and the fourth layer (C-side) on which the first capacitor 30a is mounted.

In addition, the second layer and the third layer are substantially the same pattern, except that the second layer is the N-side wiring pattern 41b and the third layer is the P-side wiring pattern 41 a. However, the structure of the printed circuit board 40 is not limited to this, and the printed circuit board 40 may be a printed circuit board 40 having two layers without the second layer and the third layer, or may be a printed circuit board 40 having more layers.

According to embodiment 6, since the cooler 10 having the plurality of concave portions 16 is used to cool the first capacitor 30a with the second cooling surface 11b and the side surface of the side wall portion 16a and cool the power module 20 with the third cooling surface 11c, the area corresponding to the first cooling surface 11a in embodiments 3 to 5 can be reduced.

In addition, when the power module 20 and the cooler 10 are reliably fixed, the P-side terminal 21a and the N-side terminal 21b extending from the power module 20 operate as a fixing mechanism that fixes the printed substrate 40 to the cooler 10 by being inserted into the connection portion 44 of the printed substrate 40. Therefore, since the portion other than the peripheral portion of the printed circuit board 40 can be fixed without using the screw 15, the flexure due to the vibration can be suppressed, and the vibration resistance can be improved.

Further, by equalizing the number of first capacitors 30a adjacent to each power module 20 and the number of second capacitors 30b adjacent to each power module 20, the wiring resistance and the wiring inductance from the first capacitors 30a and the second capacitors 30b to the power modules 20 can be equalized. Therefore, the currents flowing through the respective first capacitors 30a and the respective second capacitors 30b are almost equal, and the temperature rises are also almost equal.

Accordingly, it is not necessary to design a cooling area or a cooling structure corresponding to the smoothing capacitor 30 having the largest temperature rise, and therefore, the area of the cooling surface can be reduced, the cooling structure can be simplified, and cost reduction can be achieved.

In addition, since the distance between each power module 20 and the center of the printed circuit board 40 is shorter and the wiring resistance and the wiring inductance can be reduced as compared with embodiments 1 to 5, the temperature rise of the wiring and the switching loss at the power module 20 can be reduced. This can reduce the amount of heat received by the smoothing capacitor 30 from the wiring and the power module 20, and can suppress a temperature increase in the smoothing capacitor 30.

When the heat dissipation surface, that is, the upper surface of the power module 20 is thermally connected to the printed circuit board 40 via the heat conductive member, a heat conduction path is formed through which the heat of the power module 20 is transferred to the screw 15, the first capacitor 30a, and the cooler 10 via the printed circuit board 40. This heat conduction path is applied to a case where there is a margin for the rated temperatures of the printed circuit board 40 and the smoothing capacitor 30 and there is no margin for the rated temperature of the power module 20, and can suppress a temperature rise of the power module 20.

In addition, in the printed substrate 40, the P-side wiring pattern 41a and the N-side wiring pattern 41b are opposed in parallel with a wide area in the second layer and the third layer, and therefore, the wiring inductance generated in the P-side wiring pattern 41a and the N-side wiring pattern 41b can be reduced. Therefore, the switching loss at the power module 20 can be reduced, the amount of heat received by the first capacitor 30a from the power module 20 can be reduced, and the temperature rise of the first capacitor 30a can be reduced.

Further, by forming wiring patterns as wide as the second layer and the third layer, heat is easily diffused to the entire substrate, and heat is easily transmitted to the cooler 10 from the screws 15 disposed on the peripheral edge portion of the printed substrate 40. Therefore, the cooling effect of the printed circuit board 40 can be improved, and the temperature rise of the printed circuit board 40 can be reduced.

Embodiment 7

The power conversion device according to embodiment 7 is the same as that of embodiment 6 except for the wiring pattern of the printed circuit board 40, and therefore only the wiring pattern will be described here. The printed board 40 according to embodiment 7 is composed of six layers, fig. 21 (a) shows an example of a wiring pattern of a first layer, fig. 21 (b) shows an example of a wiring pattern of a sixth layer, fig. 22 (a) shows an example of a wiring pattern of a second layer, fig. 22 (b) shows an example of a wiring pattern of a fifth layer, and fig. 23 shows examples of wiring patterns of a third layer and a fourth layer.

The third and fourth layers of the printed board 40 are heat dissipation layers, and the others are wiring layers. The first layer (S-side) and the sixth layer (C-side) have the same wiring patterns as those of the first layer and the fourth layer (see fig. 19) of embodiment 6, except that the heat dissipation pattern 43 is provided on the peripheral edge portion. The second layer and the fifth layer have the same wiring patterns as those of the second layer and the third layer (see fig. 20) of embodiment 6, except that the heat dissipation pattern 43 is provided in the peripheral edge portion.

In the heat dissipation layer shown in fig. 23, a heat dissipation pattern 43 for mainly transferring heat of the printed board 40 is formed on almost the entire surface. The heat dissipation pattern 43 extends to screw holes in the peripheral edge of the printed circuit board 40. The heat dissipation pattern 43 formed on the peripheral edge of the wiring layer is electrically and thermally connected to the heat dissipation pattern 43 of the heat dissipation layer via the through hole 42. The heat dissipation layer is electrically and thermally connected to the screws 15 and the cooler 10 through the heat dissipation pattern 43 formed on the C-side or the S-side.

According to embodiment 7, since the printed circuit board 40 has the heat dissipation layer, the heat of the printed circuit board 40 is easily transferred to the cooler 10, and the temperature rise of the printed circuit board 40 can be reduced. If the temperature of the printed circuit board 40 is lower than that of the first capacitor 30a, the heat of the first capacitor 30a can be transferred from the printed circuit board 40 to the cooler 10, and the area of the second cooling surface 11b for cooling the first capacitor 30a can be reduced.

Since the heat dissipation layer is electrically connected to the cooler 10 and at the same potential, the heat dissipation layer serves as a shield for reducing noise radiated to an area above the heat dissipation layer by the power module 20 during switching. Therefore, the control circuit unit 5, which is susceptible to switching noise, can be disposed closer to the power module 20 than in the case where the heat dissipation layer is not provided, and the power conversion device can be downsized. Further, by including a heat dissipation layer, which is a thin metal plate, the printed circuit board 40 is less likely to be bent than in the case without the heat dissipation layer, and vibration resistance is improved.

Embodiment 8.

Fig. 24 shows a power conversion device according to embodiment 8, fig. 25 is a side sectional view of a portion indicated by G-G in fig. 24 as viewed in the direction of the arrow, and fig. 26 is a front sectional view of a portion indicated by H-H in fig. 24 as viewed in the direction of the arrow.

The power converter according to embodiment 8 includes a cover case 60 facing the S-surface 40b, which is the second surface of the printed circuit board 40, in addition to the same configuration as the power converter according to embodiment 4 (see fig. 11 and 12). The cover case 60 includes a cover main surface 61 that covers the upper portions of the printed circuit board 40 and the second capacitor 30b, and a cover leg 62 that supports the cover main surface 61.

The material of the lid case 60 is selected from metals such as aluminum, copper, tin, gold, silver, iron, alloys containing these metals, nickel alloys, ceramics such as aluminum nitride and silicon carbide, carbon-based composite materials, and the like, and the thermal conductivity is preferably 10.0W/(m · K) or more. As a method for manufacturing the cover case 60, a sheet metal may be punched to be molded, or a material in a molten or deformable state may be put into a mold and fixed.

The cover case 60 is thermally connected to the top surface of the second capacitor 30b via a heat conductive member as necessary by the cover main surface 61. As shown in fig. 26, the cover leg 62 extends from an end of the cover main surface 61 in a direction perpendicular to the cooling surface 11, and is fixed to the printed circuit board 40 and the cooler 10 by a screw 15. Thereby, the cover case 60, the screw 15, and the cooler 10 are thermally connected, and the cover case 60 is also electrically connected if it is a conductive member.

In the example shown in fig. 24 to 26, the cover case 60 covers only the upper portion of the printed circuit board 40, but may cover the upper portion of the power module 20. In this case, the range and shape of the cover case 60 need to be determined so that the cover case 60 does not interfere with the respective terminal portions of the power module 20.

According to embodiment 8, in addition to the same effects as those of embodiment 4 described above, the second capacitor 30b has a heat path from the cover case 60 side to the cooler 10, and therefore the temperature rise of the second capacitor 30b can be reduced. This can reduce the temperature rise of the first capacitor 30a, and can further reduce the area of the cooling surface.

Further, by extending the cover case 60 to the power module 20 side as well, the power module 20 has a heat path from the cover case 60 side to the cooler 10, and therefore, the temperature rise of the power module 20 can be reduced. This can reduce the area of the first cooling surface 11 a.

In addition, by pressing the entire second capacitor 30b and the printed circuit board 40 against the cooler 10 from above with the cover case 60, the flexure due to vibration is suppressed, and the vibration resistance is improved. The cover case 60 is conductive, and thus has an effect of reducing noise emitted from the power module 20 during switching. This allows the control circuit unit 5 to be disposed closer to the power module 20, thereby achieving a reduction in size of the power conversion device.

Various exemplary embodiments and examples are described in the present disclosure, but the various features, forms, and functions described in 1 or more embodiments are not limited to the application to the specific embodiments, and may be applied to the embodiments alone or in various combinations. Therefore, it is considered that numerous modifications not illustrated are also included in the technical scope disclosed in the present specification. For example, the present invention includes a case where at least one of the components is modified, added, or omitted, and a case where at least one of the components is extracted and combined with the components of the other embodiments.

Industrial applicability of the invention

The present invention can be used as a power converter, particularly as a power converter of a vehicle-mounted power supply mounted on an electric vehicle.

Description of the reference symbols

1 power conversion device

2 power conversion part

3 power smoothing

4 wiring

4a P side wiring

4b N side wiring

5 control circuit part

6 electric motor

7 cell

10 cooler

11 Cooling surface

11a first cooling surface

11b second cooling surface

11c third Cooling surface

12 refrigerant flow path

12a flow path inlet

12b flow path outlet

12c side wall channel

13 refrigerant

14 spacer

15 screw

16 concave part

16a side wall part

16c screw stop

20 power module

20a switching element

21a P side terminal

21b N side terminal

22 signal terminal

23 AC terminal

30 smoothing capacitor

30a first capacitor

30b second capacitor

31 capacitor terminal

40 printed circuit board

40a C noodle (first noodle)

40b S side (second side)

41a P side wiring pattern

41b N side wiring pattern

42 through hole

43 Heat dissipation pattern

44 connecting part

45 long hole

50 heat conduction member

60 cover shell

61 cover plate main surface

62 cover plate feet.

Claims

1. A power conversion apparatus, comprising:

a cooler having a refrigerant flow path and at least one surface formed as a cooling surface;

a power module mounted on the cooling surface;

a printed board having two or more wiring layers on which wiring patterns are formed; and

a capacitor mounted on the printed circuit board,

the capacitors include a first capacitor and a second capacitor, the first capacitor being of a higher class of capacitors whose cooling requirements are higher than the second capacitor,

the printed board is disposed so as to face the cooling surface, and when a surface of the printed board on the cooling surface side is a first surface and a surface on the opposite side to the first surface is a second surface,

the first capacitor is mounted on the first surface and thermally connected to the cooling surface, and the second capacitor is mounted on the second surface.

2. The power conversion apparatus according to claim 1,

the first capacitor and the second capacitor are smoothing capacitors.

3. The power conversion apparatus according to claim 1 or 2,

the first capacitor generates a larger amount of heat than the second capacitor.

4. The power conversion apparatus according to claim 3,

the first capacitor has a larger capacitance than the second capacitor.

5. The power conversion apparatus according to claim 3,

the first capacitor has a dielectric tangent greater than that of the second capacitor.

6. The power conversion apparatus according to any one of claims 1 to 5,

there is a difference in lifetime of the first capacitor and the second capacitor when used under the same conditions,

the first capacitor is mounted on the first surface and thermally connected to the cooling surface, and the second capacitor is mounted on the second surface, so that a difference in lifetime between the first capacitor and the second capacitor is smaller than a difference in lifetime when used under the same condition.

7. The power conversion apparatus according to any one of claims 1 to 6,

the cooler includes a recess formed in the cooling surface,

the cooling surface includes a second cooling surface that is a bottom of the concave portion and a third cooling surface that is a top of a side wall portion of the concave portion,

the printed substrate is fixed on the third cooling surface and is thermally connected with the third cooling surface,

the first capacitor is disposed inside the concave portion and thermally connected to the second cooling surface.

8. The power conversion apparatus of claim 7,

the cooler has the refrigerant flow path inside the side wall portion.

9. The power conversion apparatus according to claim 7 or 8,

the plurality of first capacitors are disposed inside the concave portion, and a part or all of the plurality of first capacitors are thermally connected to the second cooling surface and the side surface of the side wall portion.

10. The power conversion apparatus according to any one of claims 7 to 9,

includes a heat conductive member disposed between the printed substrate and the third cooling surface.

11. The power conversion apparatus according to any one of claims 7 to 10,

the printed circuit board has a through hole for electrically connecting the layers at a position facing the third cooling surface.

12. The power conversion apparatus according to any one of claims 7 to 11,

the power module includes switching elements constituting a three-phase ac inverter circuit, and a plurality of power modules constituting a U-phase, a V-phase, and a W-phase are arranged so that long sides thereof face each other, and a plurality of concave portions extending in a longitudinal direction of the power module are formed adjacent to the power module.

13. The power conversion apparatus of claim 12,

the number of the first capacitors adjacent to each of the power modules is equal.

14. The power conversion apparatus according to any one of claims 1 to 13,

the first capacitor and the second capacitor are disposed at positions not overlapping with the cooling surface of the cooler in a vertical direction.

15. The power conversion apparatus according to any one of claims 1 to 14,

the printed substrate has a connection portion electrically connected to the power module, and has a wiring pattern electrically connecting the connection portion and the capacitor.

16. The power conversion apparatus according to any one of claims 1 to 15,

the printed substrate has one or more heat dissipation layers different from the wiring layer, and the heat dissipation layers are thermally and electrically connected to the cooler.

17. The power conversion apparatus according to any one of claims 1 to 16,

the printed circuit board fixing device includes a plurality of fixing mechanisms for fixing the printed circuit board to the cooler, and at least one of the fixing mechanisms is provided at a position other than a peripheral edge portion of the printed circuit board.

18. The power conversion apparatus according to any one of claims 1 to 17,

a cover housing is included opposite the second side of the printed substrate, the cover housing being thermally connected to the second capacitor and the cooler.