JP2017147260A - heat sink - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat sink for a power conversion device for a photovoltaic power generation system capable of effectively and easily cooling a heat generating semiconductor element without increasing the size and cost thereof.SOLUTION: In a heat sink in which a heat-generating semiconductor element is configured to be attachable to one surface of a metal base board with heat conductivity, a plurality of plate-shaped heat radiation fins whose distal ends have substantially the same height are configured in parallel on the opposite other surface of the base board, and the semiconductor element is cooled by air flow between the heat radiation fins, a protruding portion having a constant height and having the other surface opposite to the attached portion of the semiconductor element protruding to the distal ends of the heat radiation fins, is integrally molded together with the base board and the heat radiation fins.SELECTED DRAWING: Figure 2

Description

The present invention relates to a heat sink for dissipating heat generated when a semiconductor element used in a power conversion device or the like is switched, and for example, a single-phase or three-phase system in which DC power obtained from renewable energy is synchronized with a system. The present invention relates to a heat sink capable of effectively dissipating heat from a semiconductor element used in a power conversion device or the like that is converted into phase AC power and can be superimposed on the system.

For example, a power conversion device (power conditioner) for a solar power generation system installed indoors
In order to obtain a product that has good heat dissipation characteristics and the case surface does not become hot, the case is a metal case, and the orthogonal transformation that converts the DC power generated by the solar cell into AC power in the case 2. Description of the Related Art A circuit and a power module of this orthogonal transformation circuit, in particular, a heat sink equipped with a heat-generating semiconductor switching element are known (see Patent Document 1).

This Patent Document 1 describes an effect that heat can be satisfactorily dissipated in the casing of the power converter, and that burns and electric shocks can be prevented when a person touches the casing of the power converter. That is, in this power converter, the heat sink to which the power module is attached is used for cooling by the air cooling method, and the surface portion of a large number of fins attached to the heat sink is brought into contact with the air in the housing, thereby generating heat. The power module can be cooled.

Like the above-described power converter, the heat sink can be effectively cooled to some extent. In the above-described power conversion device, the air flow penetrates the inside and outside of the housing, and in particular, the slit hole is formed so as to pass between the fins of the heat sink, thereby forming the air flow that goes out of the housing. Has been. In general, the size of the heat sink (cooling capacity) is designed according to the amount of heat generated by the power module, etc. For example, when the air flow inside the housing is not smooth, the cooling capacity of the heat sink was exceeded. There is a risk that the heat generated by the semiconductor switching element may be trapped in the housing. As a result, the heat resistance limit of these circuit elements may be exceeded, the characteristics of the elements may change, and the expected operation as a power conditioner may not be obtained, or the elements may be destroyed. Therefore, the design of the heat sink is set with a sufficient cooling capacity, but there is a tendency to increase the size accordingly.

In Patent Document 2, a planar upper surface portion on which an electronic component having a ceramic substrate is mounted is formed on one surface side of a plate-shaped portion made of a metal material, and on the opposite surface side of the upper surface portion, A lower surface portion in which a large number of pin-shaped fins are erected is formed, and the lower surface portion has a peripheral mounting portion and a thickness that gradually increases from the inner edge to the central portion of the mounting portion. The pin-shaped fin integrated heat sink is characterized by being formed by a central portion formed on the central portion and a large number of the pin-shaped fins erected on the central portion. It is described that the ceramic substrate, which is a brittle material, can be supported so as not to be cracked by mechanical stress such as pressure (see Patent Document 2).

FIG. 5 is an explanatory view showing a configuration of a conventional general heat sink.
The conventional heat sink 1A is, for example, an inverter circuit (
The semiconductor switching element IPM (intelligent power module) forming the INV) is mounted on the base 2 of the heat sink 1A so as to be able to conduct heat. A plurality of radiating fins 4 having a certain height are arranged in parallel on the other surface 3 side opposite to the base 2, and the IPM is cooled by the air flowing between the radiating fins 4. Has been. Reference numeral 8 denotes a mounting screw.

A case where such a conventional heat sink is used in a power conversion device for a photovoltaic power generation system will be described below. FIG. 6 is an explanatory diagram showing the relationship between current and voltage when the solar cell PV is given the amount of solar radiation required for rated output.
The direct-current power generated by the solar cell PV is supplied to a power conversion device for a solar power generation system having a schematic electrical configuration of a power conversion device for a solar power generation system shown in FIG. The rated output of the solar cell PV is when the output current peak (optimum operating point) and the optimal operating point voltage. When the amount of solar radiation decreases and the rated output of the solar cell PV cannot be obtained, this VI characteristic changes to a new VI characteristic in which the height of the peak (optimum operating point) is lowered. . In general, the peak (optimum operating point) changes so as to increase the output current when the amount of solar radiation is large, and changes so as to decrease the output current when the amount of solar radiation is small. That is, solar cell P
The output current of V changes with the amount of solar radiation if the optimum operating point voltage is maintained. Therefore, the power converter is controlled so that the solar cell PV always operates at the optimum operating point voltage regardless of the amount of solar radiation.
For example, in the case of a solar radiation amount where the current value at the peak is 30 Amp (when the rated current is 36 Amp) (not when the solar radiation amount is large), the ambient temperature is high and the IPM temperature is below the limit temperature (eg 110 ° C.) If the cooling capacity of the heat sink is not sufficient, when the amount of solar radiation increases further, the peak current value increases, and at the same time, the heat generation amount increases and the temperature of the IPM becomes higher.

In order to solve this problem, there is a method of reducing the output current by shifting the operating voltage of the solar cell PV from the voltage at the optimum operating point and reducing the output current of the solar cell PV to suppress the heat generation of the IPM. In this case, there is a problem that the rated output of the solar cell PV cannot be obtained. There are methods such as increasing the cooling capacity by increasing the size of the heat sink 1A, or increasing the cooling capacity by forcibly circulating air between the radiating fins 4 with a blower, both of which are combined with the heat sink and / or the blower. Because of the large size, new problems such as a problem that it cannot be installed in the metal enclosure and a significant increase in cost occur.

JP 2009-164351 A JP 2012-248576 A

An object of the present invention is to provide a heat sink capable of improving the cooling capacity without increasing the size.

As a result of diligent research, the inventors of the present invention attached a heat-generating semiconductor element to one surface of a metal base plate with thermal conductivity, and a tip height on the other surface on the opposite side of the base plate. A plurality of substantially equal plate-like radiating fins are installed in parallel, and in the heat sink that cools the semiconductor element by the flow of air between the radiating fins, the other opposite to the portion where the semiconductor element is attached Protrusions having a certain height projecting toward the front end side of the radiating fins on the surface, wherein the problem can be solved by providing a projecting part integrally formed with the base and the radiating fins. As a result, the present invention has been accomplished.

According to a first aspect of the present invention for solving the above-mentioned problem, a heat-generating semiconductor element can be attached to one surface of a metal substrate so as to be thermally conductive, and the other side opposite to the substrate. A plurality of plate-like heat radiation fins having a substantially equal tip height on the surface of the heat sink, and in a heat sink that cools the semiconductor element by the air flow between the heat radiation fins, relative to the mounting portion of the semiconductor element A heat sink comprising a structure in which a protruding portion having a certain height is formed by projecting the other surface facing toward the tip side of the radiating fin together with the base and the radiating fin.

According to a second aspect of the present invention, in the heat sink according to the first aspect, the projecting portion has a range including a projected area on the other surface of the semiconductor element, and the constant height is a height of the heat radiating fin. It is characterized by being in the vicinity of 15% to 22%.

According to a third aspect of the present invention, in the heat sink according to the first or second aspect, the protruding portion extends between both end portions along the direction of the heat radiating fin. is there.

According to a first aspect of the present invention, a heat-generating semiconductor element can be attached to one surface of a metal base plate so as to be thermally conductive, and a tip height is provided on the other surface on the opposite side of the base plate. A plurality of plate-like radiating fins that are substantially equal to each other in parallel, and in the heat sink that cools the semiconductor element by the flow of air between the radiating fins, the other surface facing the mounting portion of the semiconductor element is A heat sink comprising a structure in which a protruding portion having a certain height protruding toward the tip end side of the radiating fin is integrally formed with the base and the radiating fin,
The thickness of the heat sink near the semiconductor element is increased by providing a protrusion having a certain height on the other surface facing the mounting portion of the semiconductor element, thereby increasing the heat capacity. As a result, the heat transfer speed to the radiating fin is increased, leading to a decrease in temperature (cooling) of the semiconductor element. Therefore, the heat dissipation capability of the heat sink can be increased and the size can be reduced, and the heat-generating semiconductor element can be effectively and easily cooled.

According to a second aspect of the present invention, in the heat sink according to the first aspect, the projecting portion has a range including a projected area on the other surface of the semiconductor element, and the constant height is a height of the heat radiating fin. 15% to around 22% of the length,
By defining the area and the height of the protruding portion, there is a further remarkable effect that the exothermic semiconductor element can be cooled more effectively, more easily and reliably.

According to a third aspect of the present invention, in the heat sink according to the first or second aspect, the protruding portion extends between both end portions along the direction of the heat radiating fin. Yes,
There is a further remarkable effect that it is easy to be integrally formed with the base and the radiating fin.

FIG. 1 is an explanatory diagram showing a schematic electrical configuration of a power converter for a photovoltaic power generation system. FIG. 2 (a) is an explanatory view showing the configuration of the heat sink of the present invention attached to the power conversion device for a photovoltaic power generation system, and (b) shows the configuration as viewed from above (b). It is explanatory drawing, (C) is explanatory drawing which shows the structure and protrusion part which looked upward from the downward direction of (A). FIG. 3 is a characteristic diagram showing measured values of the protrusion amount of the protrusion and the temperature of the IPM (heat generating component). 4 is a perspective explanatory view of the heat sink of the present invention shown in FIG. FIG. 5 is an explanatory diagram showing a configuration of a conventional general heat sink attached to the power conversion device for a photovoltaic power generation system. FIG. 6 is an explanatory diagram showing a relationship between current and voltage of DC power generated by a solar cell of a power conversion device for a photovoltaic power generation system provided with a conventional heat sink.

Next, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is an explanatory diagram showing a schematic electrical configuration of a power conversion device for a photovoltaic power generation system.
Direct current power generated by a solar cell (PV), which is a renewable energy, is converted into a booster (DC /
The voltage is boosted by the chopper operation of the DC converter. This booster (DC / DC converter)
The DC power boosted by the D / A converter (DC / AC converter) is converted into a commercial power system (G
Converted into a predetermined low frequency pseudo sine wave AC power (DC / AC) corresponding to the frequency of RID)
Converted). The boosting unit and the D / A conversion unit are collectively referred to as an inverter unit (INV).
This AC power is superimposed on the commercial power system (GRID) as AC power in which high-frequency components are blocked or suppressed via a filter unit (LPF) constituting a low-pass filter circuit. These operations are appropriately controlled by the control circuit.

FIG. 2 (a) is an explanatory view showing the configuration of the heat sink of the present invention attached to the power conversion device for a photovoltaic power generation system, and (b) shows the configuration as viewed from above (b). It is explanatory drawing, (C) is explanatory drawing which shows the structure and protrusion part which looked upward from the downward direction of (A).
The heat sink 1 of the present invention is made of metal such as aluminum, copper, or an alloy thereof, and is manufactured by extrusion molding or die casting. In this embodiment, the heat sink 1 is molded by extrusion molding. In the heat sink 1, a heat-generating semiconductor element having a large heat generation amount is attached to one surface of a rectangular base 2 with heat conductivity. A specific semiconductor element is an IPM (intelligent power module) in which a plurality of switching elements constituting an electric circuit of an inverter unit (INV) are housed in a single package. The other surface 3 on the opposite side of the base 2
The plate-like radiating fins 4 are arranged so that the height from the base 2 to the tip is substantially equal so that a plurality of them are parallel to each other.
The air that has entered the heat sink 1 from the outside in the direction indicated by the arrows cools the heat from the IPM by the air flowing between the heat radiating fins 4. The heat radiation fins 4 are arranged so that the air acting on the cooling flows from the bottom to the top, and this air is caused by the tunnel effect caused by the rise of the air heated by the heat generated by the IPM and the air path between the heat radiation fins 4. As a result, the IPM can be cooled naturally. In addition, you may carry out forced circulation using an air blower. Further, when the front end side of the radiating fin 4 is opposed to the wall surface or the back plate, the air passage becomes cylindrical and the tunnel effect is improved.

Further, as shown in FIGS. 2 (a) to 2 (c) and FIG. 4, the base 2 has the other surface 3 opposite to the mounting portion of the IPM made of the same heat conductive material as the base 2. A protruding portion 6 having a certain height protruding toward the tip end side of the heat radiating fin 4 is formed integrally with the base 2 and the heat radiating fin 4. The structure of this integral molding is made by, for example, extrusion molding of an aluminum material,
It can also be formed by die casting. The shaded portion described in FIG.
It is.
In this embodiment, the thickness L0 of the base 2 is 6 mm, and the protruding amount (corresponding to the height) L1 of the protruding portion 6 is 10.
mm, and the height L2 from the base 2 to the tip of the radiating fin 4 is 57 mm, {(height L1 of the protrusion 6 / height L2 of the radiating fin 4) × 100-17.5%}, It is not limited to this dimension, and is appropriately designed based on the amount of heat generated by a heat-generating component such as an IPM, the size of the heat sink 1, and the presence or absence of a blower.
The protruding portion 6 preferably has an area having a range including a projected area on the other surface 3 of the semiconductor element. The area, shape, dimensions, and the like are not limited, and are appropriately designed based on the amount of heat generated by a heat-generating component such as an IPM, the size of the heat sink 1, and the presence or absence of a blower.
The thickness of the base 2 including the protruding portion 6 at that location is configured to be thicker than other locations 7 of the base 2. Reference numeral 8 denotes a mounting screw.

The thickness of the base 2 at the location is substantially increased by providing the protrusions 6, so that the IPM (
The heat capacity of the heat sink in the vicinity of the semiconductor element) becomes large, and there is room for heat supply to the radiation fins 4 by this stored heat, resulting in an increase in the heat transfer speed to the radiation fins and a decrease in IPM temperature (cooling). Leads to. Alternatively, heat energy can be temporarily stored in the protruding portion 6, and heat can be dissipated by dissipating heat to the radiating fins 4 directly connected to the protruding portion 6 and other portions 7 that are not thickened. In addition, the cooling capacity can be increased without increasing the cost, and the exothermic IPM can be effectively and easily cooled.
FIG. 3 is a characteristic diagram showing measured values of the protruding amount (horizontal axis) of the protruding portion 6 and the IPM (heat generating component) or the temperature in the vicinity (vertical axis). The horizontal axis indicates the height of the radiation fin 4. The ratio (%) of the height L1 of the protrusion 6 to L2 and the value of L1 are described. From the temperature when the protrusion amount is 0 mm (conventional structure), the temperature decreases rapidly as the protrusion amount is increased to 5 mm and 10 mm.
On the other hand, when the thickness is increased to 20 mm and 25 mm, the temperature rises conversely, but is lower than the temperature when the protrusion amount is 5 mm.
Therefore, although the temperature reduction effect of the IPM can be obtained by providing the projecting portion 6, there is no effect corresponding to the projecting amount even if the projecting amount is increased. Therefore, the metal (aluminum) required by increasing the projecting amount is not provided. 20mm or less is reasonable when considering the increase in weight due to the increase in the temperature, etc., but the effective range including the lowest point of the IPM temperature is 13mm or less (the height to the tip of the radiating fin is 57mm). (Approx. 22% or less) is suitable. Also, considering the range of good characteristics when changing the shape of the heat sink fins of the heat sink, the protrusion amount of the protrusion is 8 mm or more (
A ratio of about 15% or more in the ratio of the height to the tip of the radiating fin is 57% or more) is suitable. However, if priority is given to weight reduction, if the thickness is about 5 mm, a considerable temperature reduction effect of IPM can be expected.
In this embodiment, thermal analysis software was used in consideration of variations in setting conditions for temperature measurement, but the same measurement results can be obtained even if actually measured using a temperature sensor (thermocouple, etc.). It is.

The manufacturing method of the protrusion part 6 is not specifically limited, Specifically, for example, the heat sink 1 is used.
It may be made by extrusion molding or die casting at the time of manufacture, or it may be added after the heat sink 1 is manufactured, and it may be made integrally by welding or screwing, or a synthetic resin or metal with good thermoelectric conductivity is used. Any manufacturing method may be used as long as the heat sink 1 can be manufactured without losing thermal conductivity, mechanical strength, etc., and durability. The thickness and area are also suitable for the solar cell to be used, and are preferably designed to have a cooling capacity so that all the electric power generated by the solar cell can be used effectively and determined by testing in advance.

In the above example, the material having the same thermal conductivity as that of the base 2 was used as the material of the protruding portion 6.
It is preferable that the heat sink 1 provided with the protrusions 6 is integrally formed when the heat sink 1 is extruded. However, the same material may be used when the protrusion 6 is added after the heat sink 1 is manufactured and is integrally formed by welding or screwing, but it is a material excellent in thermal conductivity, mechanical strength, durability, etc. As long as it is a material that can produce an excellent heat sink 1, a material different from the base 2 can be used, or the same material and a different material can be used in combination.
In the present embodiment, the height (projection amount) of the protrusion 6 is constant, but it can be modified within a range where the heat capacity by the protrusion 6 is not reduced.

The description of the above embodiment is for explaining the present invention, and does not limit the invention described in the claims or reduce the scope thereof. Moreover, each part structure of this invention is not restricted to the said embodiment, A various deformation | transformation is possible within the technical scope as described in a claim.

The present invention is configured so that a heat-generating semiconductor element can be attached to one surface of a metal base with heat conductivity, and the tip of the plate is substantially equal in height to the other surface on the opposite side of the base. A heat sink comprising a plurality of heat radiation fins arranged in parallel and cooling the semiconductor element by an air flow between the heat radiation fins, the other surface facing the mounting portion of the semiconductor element is the tip of the heat radiation fin A heat sink comprising a structure in which a protrusion having a certain height protruding toward the side is formed integrally with the base and the heat dissipating fin, and the other opposite to the mounting portion of the semiconductor element By providing a thick protrusion on the surface, the heat energy can be temporarily stored there, and then dissipated by conducting heat to the fins and other parts where the thickness is not increased. Therefore, the cooling capacity can be increased without increasing the size and cost of the heat sink, and the remarkable effect that the heat-generating semiconductor element can be effectively and easily cooled is achieved. It ’s big.

DESCRIPTION OF SYMBOLS 1, 1A Heat sink 2 Base 3 The other surface on the opposite side of the base 4 Radiation fin 6 Protrusion 7 Other location 8 Mounting screw L0 Base thickness L1 Protrusion height L2 Height from base to tip of heat dissipation fin

Claims (3)

A heat-generating semiconductor element can be attached to one surface of a metal base plate with thermal conductivity, and a plurality of plate-shaped plurality of tips whose heights are substantially equal to the other surface on the opposite side of the base plate. In the heat sink that configures the heat radiation fins in parallel and cools the semiconductor element by the air flow between the heat radiation fins, the other surface facing the mounting portion of the semiconductor element is directed toward the tip side of the heat radiation fin. A heat sink comprising a structure in which a protruding portion having a certain height is integrally formed with the base and the heat dissipating fin. The protrusion has a range including a projected area on the other surface of the semiconductor element, and the fixed height is approximately 15% to 22% of the height of the radiation fin. Item 1. A heat sink according to item 1. The heat sink according to claim 1, wherein the protruding portion extends between both end portions along the direction of the radiation fin.

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