JP2016146438A - Power converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem that the internal temperature of a housing increases due to the heat released from a heating component, such as a conductor switching element or a reactor, into the housing.SOLUTION: A die-cast housing 10 is cooled by providing outer heat dissipation fins 10o on the upper outside and the back of the housing 10, and inner heat dissipation fins 10i are provided on the upper inside of the housing 10, at the same positions as the outer heat dissipation fins 10o on the upper outside and the back of the housing 10, so that the heat released into the housing 10 from heating components, such as a semiconductor switching element 4a, a DC reactor 3a, an AC reactor 5a, and the like, is transmitted to the inner heat dissipation fins 10i provided above the housing.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power conversion device having a heat dissipation structure.

  2. Description of the Related Art Conventionally, power conversion devices such as solar power generation using solar cells, wind power generation using wind power, storage batteries, or fuel cells have been put into practical use by converting DC power into AC power and supplying it to a load or power system. The power conversion device converts DC power into AC power by a power conversion circuit having functional elements such as a semiconductor switching element and a reactor.

  When these power converters operate, exothermic parts such as semiconductor switching elements or reactors generate a lot of heat, and thus must be housed in a casing having an appropriate heat dissipation structure and cooled. Patent Document 1 describes this cooling structure.

  In Patent Document 1, heat radiation is provided by a structure in which heat radiation fins are provided on the rear surface of a substantially cubic housing having an opening in a front surface portion obtained by die casting of an aluminum alloy, and the heat radiation fins are cooled by a blower. Done. Die-casting is one of die casting methods, and is a casting method that produces a large amount of castings with high dimensional accuracy in a short time by press-fitting molten metal into the die.

JP 2014-207845 A

  However, according to the technique of Patent Document 1, the heat transferred to the housing by heat conduction can be cooled by the heat radiation fins on the back surface of the housing, but from the heat-generating parts such as semiconductor switching elements and reactors to the housing. The heat dissipated inside cannot be effectively dissipated, and there is a problem that the internal temperature of the housing rises due to the heat.

  The present invention has been made in view of the above, and can effectively dissipate heat released from a heat generating component such as a semiconductor switching element or a reactor into the housing, thereby suppressing a temperature rise inside the housing. An object of the present invention is to obtain a power conversion device having a heat dissipation structure.

  In order to solve the above-described problems and achieve the object, a power conversion device of the present invention uses a semiconductor switching element, an inverter circuit that converts DC power into AC power, a DC reactor, and power having an AC reactor The housing includes a conversion circuit unit, a power conversion circuit unit, a housing having an opening in the front surface portion, and a front cover that covers the opening of the housing. An outer heat radiation fin is provided on the outer side of the housing, and an inner heat radiation fin is provided on the inner side of the housing. The outer heat radiation fin and the inner heat radiation fin are located on the housing in a straight line through the housing. It is characterized by that.

  According to the present invention, it is possible to suppress an increase in temperature inside the casing by effectively conducting heat released from the heat generating components such as semiconductor switching elements and reactors to the inside of the casing. To do.

Front view of power converter of Embodiment 1 The principal part enlarged view of the power converter device of Embodiment 1 AA sectional view which is a cross section of the power converter of Embodiment 1 BB sectional view which is a longitudinal section of the power converter of Embodiment 1 The rear perspective view of the power converter of Embodiment 1 Block diagram of power converter of Embodiment 1 The principal part enlarged view of the power converter device of Embodiment 2

  Hereinafter, a power converter according to an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
1 is a front view of a power conversion device according to a first embodiment of the present invention, FIG. 2 is an enlarged view of a main part of the power conversion device, and FIG. 3 is a cross-sectional view of the power conversion device of FIG. -A sectional view, FIG. 4 is a BB sectional view which is a longitudinal section of the power converter of FIG. 1, and FIG. 5 is a rear perspective view of the power converter. FIG. 6 is a block diagram of the power converter. In addition, although the front surface of the power converter is originally covered with the front cover, FIG. 1 shows a view seen through the front cover. As shown in FIG. 1 and FIG. 2, the power conversion device 100 according to the present embodiment includes an outer radiating fin 10 o provided outside the casing 10 that houses the power conversion circuit unit 2, and an inner side of the casing 10. The provided inner radiating fin 10i is positioned on a straight line through the casing 10, and a heat transfer path along the arrow is formed so that heat can be efficiently radiated. The outer radiation fin 10o constitutes the rear outer radiation fin 10r on the rear surface R.

As shown in FIG. 6, in the electric circuit of the power conversion apparatus 100 according to the present embodiment, a DC power source 1 that generates DC power, for example, a solar cell, is connected to a DC side input 2 _in of the power conversion circuit unit 2. Is done. The AC output 2 _out of the power conversion circuit unit 2 is connected to the commercial power system 8. A load 7 such as a home appliance is connected to the commercial power system 8. The power conversion circuit unit 2 is connected to the inverter circuit 4 via the DC filter circuit 3 so that high-frequency noise or the like does not flow out to the DC power supply 1. The DC filter circuit 3 includes a booster circuit (not shown) that boosts the voltage of the DC power supply 1 to a voltage at which the inverter circuit 4 can operate. In the inverter circuit 4, the input DC power is converted into AC by inverter technology. The output of the inverter circuit 4 is connected to the commercial power system 8 via the AC filter circuit 5 so that high frequency noise or the like does not flow out to the commercial power system 8 or the load 7 such as home appliances. Open and close connection to system 8.

  FIG. 1 is a front view of a power conversion device 100 according to the present embodiment, which is obtained by die-casting an aluminum alloy, and has a power conversion circuit inside a substantially cubic body case 10 having an opening in the front portion. Each part which comprises the part 2 is attached. Each component is arranged throughout the housing 10, and the semiconductor switching element 4 a which is a heat generating component of the power conversion circuit unit 2 and a component of the inverter circuit 4 is directly fixed to the housing 10, and the semiconductor switching element 4 a. The heat generated from the heat is directly transferred to the housing 10. The direct current reactor 3a of the direct current filter circuit 3 and the alternating current reactor 5a of the alternating current filter circuit 5 are attached to the recessed portion O of the housing 10 and are thermally coupled to the housing 10 by a resin mold or an insulating heat conductor. The heat generated from the DC reactor 3a and the AC reactor 5a is directly transferred to the casing 10.

  As shown in FIG. 3, the housing 10 is provided with a plurality of rear outer radiation fins 10 r for radiating the heat transferred to the housing 10 on the rear surface. FIG. 3 is a cross-sectional view taken along the line AA of FIG. Further, as shown in FIG. 1, a plurality of outer radiating fins 10 o are provided on the outer side of the upper surface at the upper portion of the housing 10, and a plurality of inner radiating fins are also provided on the inner side of the housing 10 at the same position as the outer radiating fins 10 o 10i is provided.

As shown in FIG. 6, a DC filter circuit 3 having a DC reactor 3a mounted therein and a semiconductor switching element 4a mounted on a circuit board 4b to convert the DC power into AC power, as shown in FIG. And a power conversion circuit unit 2 having an AC filter circuit 5 on which an AC reactor 5a is mounted. In the power conversion apparatus according to the first embodiment, for example, it is output via a DC filter circuit 3 including a step-up / step-down circuit (not shown) and a DC reactor 3a that step up or step down DC power from a DC power source 1 made of a solar cell module. A semiconductor switching element 4a that controls DC power to be converted into AC power, an electrolytic capacitor 4c that accumulates electric charge by DC power, and an AC reactor 5a that removes high-frequency components from the output of the semiconductor switching element 4a are arranged. Yes. The control circuit C is composed of an L-shaped substrate, includes a connection relay 6 for connecting AC power to the power system, and controls the semiconductor switching element 4a or the connection relay 6. Although the interconnection relay 6 is illustrated in the block diagram of FIG. 6, on the circuit board constituting the control circuit C, the interconnection relay 6 is disposed below the AA cross section of FIG. Not shown. The terminal block T with the input and output terminals T _i in a region surrounded by the L-shaped substrate of the control circuit C is arranged.

  FIG. 4 is a BB cross-sectional view showing a vertical cross section of the present embodiment, and the front cover 11 that covers the front surface of the housing 10 having an opening in the front portion infiltrates rainwater when installed outdoors. In order to prevent this, the contact surface with the casing 10 is sealed with the packing 12. The inner radiating fins 10 i of the housing 10 are configured in a substantially L shape inside the upper portion of the housing 10 in order to increase the heat transfer area and facilitate heat exchange of the heat inside the housing 10. As shown in FIG. 4, the housing 10 has a cubic shape, and the inner radiating fins 10 i are formed in an L shape extending from the upper surface U of the housing 10 to the rear surface R along the inner wall of the housing 10 as shown in FIG. It has a contact surface.

  As described above, the inner radiating fins 10i and the outer radiating fins 10o are integrally molded together with the housing 10 by die casting. The inner radiating fin 10i and the outer radiating fin 10o have the same thickness. The thickness of the casing 10 in the region sandwiched between the inner radiating fins 10i and the outer radiating fins 10o is equal to or smaller than the thickness of the inner radiating fins 10i and the outer radiating fins 10o. Thereby, the material which comprises the housing | casing 10 can be decreased, ensuring the favorable thermal radiation path from the inner side radiation fin 10i to the outer side radiation fin 10o including the back surface outside radiation fin 10r.

  The semiconductor switching element 4a is formed of, for example, silicon carbide (SiC), gallium nitride (GaN) -based material, or a wide band gap (WBG) semiconductor such as diamond. Since the semiconductor switching element 4a formed of these WBG semiconductors can operate at a high temperature of about 200 ° C. or higher, it is disposed in the upper part of the housing 10 as a high temperature region as shown in FIG. The electrical connection between the semiconductor switching element 4a and the circuit board 4b of the inverter circuit 4 is achieved by wire bonding via a bonding wire 4w. When the semiconductor switching element 4a is formed of a WBG semiconductor, it can operate at a high temperature, so that the size of the housing can be reduced as compared with the case where the semiconductor switching element 4a is made of a material other than the WBG semiconductor such as Si. However, in that case, the internal temperature of the housing easily rises.

  The electrolytic capacitor 4c is a low heat generating component. Since the life is shortened in a high temperature environment, it is desirable to arrange in a region where the temperature is low in the housing 10, but it is a component of the inverter circuit 4 and also needs to be arranged in the vicinity of the semiconductor switching element 4a. In the present embodiment, it is disposed in the vicinity of the inner wall of the housing 10, which is a region where the temperature is relatively low. If possible, the electrolytic capacitor 4c may be disposed in the lower part of the housing 10.

  Since the DC reactor 3a and the AC reactor 5a are heat-generating components that generate a large amount of heat during operation, like the semiconductor switching element 4a, the DC reactor 3a and the AC reactor 5a are located near the inner wall of the housing 10 together with the semiconductor switching element 4a. It is desirable to be placed.

  Similarly to the electrolytic capacitor 4c, the interconnection relay 6 is a low heat generation component that generates a small amount of heat during operation, and the operating voltage range becomes narrow under a high temperature environment. Therefore, the interconnection relay 6 is located below the semiconductor switching element 4a that is a heat generation component and It is arranged at a remote location. Moreover, it is desirable to arrange | position in the area | region where heat dissipation is favorable with the electrolytic capacitor 4c.

  As described above, since the control circuit C is equipped with relatively low heat generating components such as the interconnection relay 6, the amount of heat generated during operation is relatively small.

  FIG. 5 is a rear perspective view of the present embodiment. A plurality of rear outer radiating fins 10r are provided on the rear surface R of the housing 10, and the rear outer radiating fins 10r are provided in order to improve the air flow on the rear surface R. It is divided into three stages in the height direction. The number of divisions is not limited to three, and can be changed as appropriate. In the present embodiment, external heat radiation is performed by a natural convection method. However, a forced convection method may be employed by attaching a blower (not shown) so that the rear outer radiation fins 10r can be cooled.

  Next, operation | movement of the thermal radiation structure of the power converter device of this Embodiment is demonstrated. When the power conversion circuit unit 2 operates, the DC reactor 3a of the DC filter circuit 3 and the AC reactor 5a of the AC filter circuit 5 generate heat. The generated heat is transferred from the recessed portion O of the housing 10 to the housing 10. However, the direct current reactor 3a and the alternating current reactor 5a have a thickness, a part of the direct current reactor 3a protrudes to the front surface, and the whole cannot be embedded in the recessed portion O of the housing 10, so that heat is also radiated to the inside of the housing 10. Similarly, when the power conversion circuit unit 2 operates, the semiconductor switching element 4 a also generates heat and is transferred to the housing 10 from the contact surface with the housing 10, but also dissipates heat inside the housing 10. In addition, heat is generated from the components of the DC filter circuit 3, the inverter circuit 4, and the AC filter circuit 5, such as the electrolytic capacitor 4 c as well as components such as coil components and wiring (not shown), and is dissipated into the housing 10.

  The heat radiated to the inside of the casing 10 is transmitted to the upper part of the casing 10 by internal convection, and is transferred to the casing 10 by the inner radiation fins 10i. Further, as shown in FIG. 2, a plurality of inner radiating fins 10i and outer radiating fins 10o are arranged in a direction perpendicular to the casing 10, and the inner radiating fins 10i and the outer radiating fins 10o are located at the same position. Therefore, the heat conduction path between the inner radiating fins 10i and the outer radiating fins 10o is shortened, and the heat of the heat radiating fins 10i that has been transferred is easily conducted to the outer radiating fins 10o. Similarly, by providing the rear outer radiation fin 10r in the outer radiation fin 10o at the same position as the inner radiation fin 10i, heat conduction from the inner radiation fin 10i to the rear outer radiation fin 10r is facilitated.

  Since the inside of the housing 10 has a higher temperature at the top, the effect of providing the inner heat radiation fins 10 i at the top of the housing 10 is great. However, it is necessary to incorporate a large number of components such as the DC filter circuit 3, the inverter circuit 4, and the AC filter circuit 5 in the housing 10, and it is desirable that the housing 10 be as small as possible. By providing the inner heat radiation fin 10i in a substantially L shape between the bottom surface and the top surface of the circuit board 4b of the inverter circuit 4, the heat radiation area can be increased and heat radiation can be facilitated.

  Moreover, as shown in FIG. 5, the back surface external radiation fin 10r provided in the back surface R of the housing | casing 10 is partly divided | segmented into 3 steps | paragraphs in the height direction. When the heat of the high heating element such as the upper semiconductor switching element 4a is not uniformly transferred to the rear external heat radiation fin 10r, the temperature of the H portion shown in FIG. 5 rises. Since the rear external heat radiation fin 10r is divided into three stages, even in such a case, the air flow of the rear external heat radiation fin 10r also flows to the low temperature part as indicated by the arrow Ar, and efficiently radiates heat. be able to.

  In the present embodiment, the heat of the inner radiating fin 10i is described as being conducted to the outer radiating fin 10o and the rear outer radiating fin 10r. However, the DC filter circuit 3, the inverter circuit 4, and the AC filter circuit 5 generate heat. If the number is small, it is possible to omit either one or a part of the outer radiating fin 10o or the rear outer radiating fin 10r. Also in this case, efficient heat radiation is realized by leaving the rear external heat radiation fin 10r in a region facing the inner heat radiation fin 10i through the wall surface of the housing 10.

  Further, in the present embodiment, the structure in which the inside of the housing 10 is sealed from the outside by the front cover 11 in order to be installed outdoors has been described. However, in the case of indoor installation equipment, it is not necessary to have a sealed structure. However, since the power conversion circuit unit 2 has a high voltage circuit, it needs to have a structure close to sealing in order to prevent an electric shock, and can be similarly applied to an indoor installation.

  With such a structure, the heat radiated from the heat generating components such as the semiconductor switching element 4a, the DC reactor 3a, and the AC reactor 5a to the inside of the housing 10 is conducted to the housing 10 by the inner heat radiating fins 10i, whereby the inside of the housing 10 is This has the effect of suppressing the temperature rise.

Embodiment 2. FIG.
FIG. 7 is an enlarged view of a main part of the power conversion device according to the second embodiment of the present invention. In the power conversion device 100 according to the present embodiment, the outer radiating fin 10o provided outside the housing 10 that houses the power conversion circuit unit 2 changes its direction and moves outward as it moves away from the housing 10. It is arranged to spread. The outer radiating fins 10o provided on the outer side of the casing 10 are in a straight line with the inner radiating fins 10i provided on the inner side of the casing in the vicinity of the region in contact with the casing 10. positioned. And it is comprised so that it may spread outside in the outer side of a housing | casing.

  According to the power conversion device of the second embodiment, an efficient heat transfer path along the arrow is formed in the region from the inner radiating fin 10i to the outer radiating fin 10o, and the outer radiating fin 10o is outward on the outer side. More efficient heat dissipation is realized by bending so as to spread.

  As described above, according to the power conversion devices of the first and second embodiments, the outer radiating fins provided outside the casing and the inner radiating fins provided inside the casing include the casing. The heat generated in the housing can be transferred from the inner radiating fins to the outer radiating fins in a straight line, minimizing thermal resistance, and heat dissipation. Can be increased.

  Further, since the inner heat radiation fin has an L-shaped contact surface extending from the top surface of the housing to the back surface along the inner wall of the housing at the upper portion of the housing, heat from above is transferred to the two surfaces of the top surface and the back surface. By conducting efficiently and transmitting to the outer heat dissipating fins provided opposite to each other, heat can be radiated extremely efficiently.

  Since the inner radiating fin and the outer radiating fin are formed by integral molding with the housing, they are extremely easy to manufacture and have good heat dissipation.

  Since the thickness of the housing in the region sandwiched between the inner and outer radiating fins is equal to the thickness of the inner and outer radiating fins, manufacturing by casting is easy and the radiating characteristics are also good. . Alternatively, the thickness of the casing in the region sandwiched between the inner and outer radiating fins is smaller than or equal to the thickness of the inner and outer radiating fins, thereby increasing the thermal resistance in the direction along the casing. doing. Therefore, the material constituting the housing 10 can be reduced while securing the heat radiation path in the direction connecting the inner and outer heat radiation fins in the housing portion, not in the lateral direction.

  The AC output of the power conversion circuit unit is connected to a commercial power system, and even when the heat generation amount of the power conversion circuit unit is high, the power conversion device of the present embodiment can realize efficient heat dissipation. In addition, when a wide band gap semiconductor is used as a semiconductor switching element to reduce the size of the housing, the efficiency according to the present embodiment is also prevented in order to prevent the temperature inside the housing from increasing and affecting other components. A good heat dissipation structure is effective.

  In the above embodiment, the casing, the outer radiating fin, and the inner radiating fin are formed by die casting using an aluminum alloy. However, in addition to the aluminum alloy, the casing, the outer radiating fin, and the inner radiating fin may be made of a material having a low melting point such as a zinc alloy. desirable. As long as the material has high thermal conductivity, a resin material may be used without being limited to metal.

  Needless to say, the layout inside the housing can be changed as appropriate.

  1 DC power supply, 2 power conversion circuit unit, 3 DC filter circuit, 3a DC reactor, 4 inverter circuit, 4a semiconductor switching element, 5 AC filter circuit, 5a AC reactor, 6 interconnection relay, 7 load, 8 commercial power system, DESCRIPTION OF SYMBOLS 10 Housing | casing, 10r back surface outside radiation fin, 10o outside radiation fin, 10i inside radiation fin, 11 front cover, 12 packing, U upper surface, R back surface, 100 power converter.

Claims (9)

An inverter circuit that converts DC power into AC power using a semiconductor switching element, a DC reactor, and a power conversion circuit unit having an AC reactor,
While housing the power conversion circuit unit, a housing having an opening on the front surface,
A front cover covering the opening of the housing;
An outer radiating fin provided on the outside of the housing;
An inner heat dissipating fin provided inside the housing;
The outer radiating fin and the inner radiating fin are arranged on the casing via the casing.
A power conversion device, which is located on a straight line.   2. The electric power according to claim 1, wherein the inner radiating fin has an L-shaped contact surface extending from an upper surface to a rear surface of the housing along an inner wall of the housing at an upper portion of the housing. Conversion device.   The said inner side radiation fin and the said outer side radiation fin are arranged in multiple numbers by the orthogonal | vertical direction with respect to the said housing | casing, The said housing | casing was formed by integral molding, The Claim 1 or 2 characterized by the above-mentioned. Power conversion device.   The power converter according to any one of claims 1 to 3, wherein the inner radiating fin and the outer radiating fin have the same thickness.   The thickness of the housing | casing of the area | region pinched | interposed by the said inner side radiating fin and the said outer side radiating fin is smaller than or equal to the thickness of the said inner side radiating fin and the said outer side radiating fin. Power converter.   The power converter according to claim 1, wherein the inner radiating fin, the outer radiating fin, and the casing are formed by die casting.   The power conversion device according to claim 1, wherein the outer radiating fin spreads outward at a position away from a surface on the housing.   The power conversion device according to claim 1, wherein the semiconductor switching element is formed of a wide band gap semiconductor.   The power converter according to any one of claims 1 to 8, wherein the AC output of the power conversion circuit unit is connected to a commercial power system.

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