JPWO2019107358A1 - Sealed electronic device - Google Patents

Abstract

The sealed electronic device is installed on a base plate (1) located in a lower layer in a sealed housing, and a first substrate (2,) on which a plurality of elements including heat generating elements (4,5,6,7) are mounted 3), the second substrate (10, 11) installed on the upper plate (8) located on the upper layer of the base plate in the housing and mounting a plurality of elements, and the upper plate installed on the upper plate toward the heat generating element. It is provided with a blower (12) that blows cooling air.

Description

The present invention relates to a sealed electronic device in which a substrate on which a large number of electronic components are mounted is housed in a sealed housing.

In a photovoltaic power generation system for general households, DC power generated by a solar panel is converted into commercial AC power by a power conditioner and supplied to an AC load in the home or a commercial power system.

Specifically, the direct current power generated by the solar panel is boosted by the PV (photovoltaic) converter and converted into commercial AC power by the inverter. Then, the AC load or the commercial AC power is supplied from the inverter to the commercial power system.

In a relatively low-power power conditioner for home use, which is premised on outdoor installation, a PV converter board on which a large number of electronic components constituting the PV converter are mounted and an inverter are configured in a sealed housing. It houses an inverter board or the like on which a large number of electronic components are mounted.

The PV converter board is equipped with a reactor and a switching element for boosting the DC voltage, and the inverter board is mounted with a reactor and a switching element for converting DC power into AC power.

Since these elements generate a large amount of heat, and especially in a closed type housing, it is not possible to take a means of taking in outside air to enhance the heat dissipation effect. Therefore, in addition to heat transfer by heat transfer by a heat sink or the like, a fan is installed inside the closed type housing. It is important to efficiently circulate the air inside the housing by providing it.

As a heat radiating structure that dissipates heat generated from an electronic component mounted on a substrate, the one disclosed in Patent Document 1 is known.

JP-A-2007-221057

In the heat dissipation structure disclosed in Patent Document 1, a heat generating element, a heat sink, and a fan are mounted close to each other on the same printed circuit board. Therefore, since these mounting areas increase, the printed circuit board becomes large, and the housing for accommodating the printed circuit board becomes large. Further, depending on the layout of the elements on the substrate, the circulating air sent from the fan may not sufficiently reach the heat generating element and the heat sink.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a sealed electronic device capable of stably cooling a heat generating element on a substrate by blowing air from a blower.

A sealed electronic device that solves the above problems is installed on a base plate located in a lower layer in a sealed housing, and is mounted on a first substrate on which a plurality of elements including heat generating elements are mounted and on the upper layer of the base plate in the housing. It includes a second substrate installed on a located upper plate and mounted with a plurality of elements, and a blower installed on the upper plate and blowing cooling air toward the heat generating element.

With this configuration, cooling air is blown from the blower installed on the upper plate to the heat generating element on the base plate to cool the heat generating element.
Further, in the above-mentioned sealed electronic device, it is preferable to install the blower diagonally downward so that the cooling air is directed toward the heat generating element.

With this configuration, the cooling air is blown diagonally downward from the blower toward the heat generating element.
Further, in the above-mentioned sealed electronic device, it is preferable to position the lower edge of the blower between the base plate and the upper plate.

With this configuration, it is possible to reduce the height of the blower installed on the upper plate.
Further, in the above-mentioned sealed electronic device, it is preferable that the upper plate has a shape that does not cover the upper part of the heat generating element so that the cooling air is directed toward the heat generating element.

With this configuration, cooling air is blown from the blower toward the heating element.
Further, in the above-mentioned sealed electronic device, it is preferable that the heat generating element includes at least one of a reactor and a power semiconductor element.

With this configuration, the reactor or power semiconductor element is cooled by the cooling air.
Further, in the above-mentioned sealed electronic device, it is preferable to mount a smoothing capacitor on the first substrate on the circulation path of the cooling air circulating in the housing.

With this configuration, the smoothing capacitor is cooled by the cooling air.
Further, in the sealed electronic device, it is preferable that the inverter and the PV converter are mounted on the first substrate, and the control circuit of the inverter and the PV converter is mounted on the second substrate. ..

With this configuration, the heat generating element is mounted on the first substrate.
Further, it is preferable that the sealed electronic device is provided with heat radiation fins on the back surface of the base plate.

With this configuration, the heat dissipated from the cooling air to the housing is dissipated from the heat radiation fins to the outside of the housing.

According to the sealed electronic device of the present invention, the heat generating element on the substrate can be stably cooled by blowing air from the blower.

The perspective view which shows the appearance of the power conditioner of one Embodiment. The perspective view which shows the internal structure of the power conditioner of one Embodiment. The exploded perspective view which shows the internal structure of the power conditioner of one Embodiment. A side view showing the cooling air blown from the blower.

Hereinafter, embodiments that are one aspect of the present invention will be described with reference to the drawings. 1 and 2 show power conditioners constituting a photovoltaic power generation system for general households.
FIG. 1 shows an external view in which the lid portion 21 is covered and the closed type is formed, and FIG. 2 shows an internal configuration diagram in which the lid portion 21 is removed.

The base plate 1 constituting the housing is made of a metal having thermal conductivity, and the PV converter board 2 and the inverter board 3 are installed on the base plate 1.
A PV converter including a booster circuit for boosting the generated power of the solar panel is mounted on the PV converter substrate 2. The booster circuit is composed of a non-isolated chopper circuit, and includes a plurality of reactors 4 serving as heat generating elements and a plurality of switching elements (power semiconductor elements) 5 through which a large current flows.

As shown in FIG. 2, the reactor 4 is mounted close to one end side (front side in FIGS. 1 and 2) of the PV converter board 2, and the switching element 5 is mounted near the other end side of the PV converter board 2. There is. Further, a plurality of smoothing capacitors 19 composed of aluminum electrolytic capacitors are mounted between the reactor 4 and the switching element 5.

The reactor 4 is mounted side by side along one end edge of the PV converter board 2, and the smoothing capacitor 19 and the switching element 5 are mounted side by side in the same direction as the reactor 4, respectively.

On the inverter board 3, an inverter that converts the DC power boosted by the PV converter into commercial AC power of 50 Hz or 60 Hz is mounted. The inverter is composed of a bridge converter including a half bridge or a full bridge, and includes a reactor 6 as a heat generating element and a switching element (power semiconductor element) 7 through which a large current flows.

Further, a plurality of smoothing capacitors 20 composed of aluminum electrolytic capacitors are mounted on the rear and side of the switching element 7 (see FIG. 3).
As shown in FIG. 2, the reactor 6 and the switching element 7 are mounted close to one end side (front side in FIGS. 2 and 3) of the inverter board 3.

An upper plate 8 is arranged above the PV converter board 2 and the inverter board 3. The upper plate 8 is formed of a metal plate made of the same material as the base plate 1 in a substantially L shape, and is formed above the boundary portion between the PV converter board 2 and the inverter board 3 and the other end side of the inverter board 3 (FIGS. 2 and 2). While covering the upper side (rear side in 3), the upper side of the reactor 6 and the switching element 7 is open.

Then, each corner of the upper plate 8 is fixed to the base plate 1 via the fixing pin 9. Further, a space is secured between the lower surface of the upper plate 8 and the elements mounted on the PV converter board 2 and the inverter board 3 so that the cooling air can be circulated.

On the upper plate 8, a control board 10 on which a control circuit for controlling the booster circuit mounted on the PV converter board 2 is mounted and a control circuit for controlling the inverter mounted on the inverter board 3 are mounted. The control board 11 is installed. Therefore, the PV converter board 2, the inverter board 3, and the control boards 10 and 11 are separately installed in two layers, one on the base plate 1 which is the lower layer in the housing and the other on the upper plate 8 which is the upper layer.

A blower 12 is installed on the upper plate 8 at a position above the middle portion in the front-rear direction of the inverter board 3. More specifically, in the blower 12, a fan 14 rotationally driven by a motor is supported by a case 13. Mounting pieces 15 are formed in the vertical intermediate portion of the case 13 on both sides of the fan 14 in the radial direction.

A recess 16 is formed on the front edge of the upper plate 8 located above the inverter board 3 so that the case 13 can be inserted from above or from the front, and support portions 17 for supporting the mounting piece 15 are formed on both sides of the recess 16. Is provided. Then, the blower 12 is fixed to the upper plate 8 by inserting the case 13 into the recess 16 and screwing the mounting piece 15 to the support portion 17.

Therefore, as shown in FIG. 4, the lower edge of the case 13 of the blower 12 is located between the base plate 1 and the upper plate 8.
Further, as shown in FIG. 4, the blower 12 is attached diagonally downward so that the fan 14 faces the reactor 6, and when the fan 14 is rotated, the cooling air is blown from the blower 12 toward the reactor 6. W is designed to be blown. The blower 12 operates when the booster circuit of the PV converter and the inverter are operated to blow the cooling air W toward the reactor 6 on the inverter board 3.

A heat radiation fin 18 is attached to the back surface of the base plate 1. The heat radiating fin 18 is made of a metal of the same material as the base plate 1, and heat dissipated from the heat generating element on the PV converter substrate 2, the heat generating element on the inverter board 3, and the cooling air W to the base plate 1 causes the heat radiating fin 18. It is dissipated to the outside of the housing via.

As described above, when the PV converter board 2 and the inverter board 3 are installed on the base plate 1, the control boards 10 and 11 and the blower 12 are installed on the upper plate 8, the side plate is attached to the base plate 1 and the lid portion 21 is covered. , A closed power conditioner is formed.

Next, the operation of the power conditioner configured as described above will be described.
When the power conditioner is operated, the reactor 4 and the switching element 5 on the PV converter board 2 generate heat, and the reactor 6 and the switching element 5 on the inverter board 3 generate heat. Further, the smoothing capacitor 19 on the PV converter board 2 and the smoothing capacitor 20 on the inverter board 3 also generate heat due to the flow of the ripple current.

Aluminum electrolytic capacitors used as smoothing capacitors are preferably used at as low a temperature as possible because the evaporation (dry-up) of the electrolytic solution inside is directly related to the product life due to the structure of the parts. In general, measures such as increasing the capacitance to reduce the difference between the maximum and minimum values of the flowing ripple current, avoiding placement in a place with a high ambient temperature, or placing in a place exposed to cooling air. Is taken.

Therefore, when the power conditioner is operated, the cooling air W is blown from the blower 12 toward the reactor 6 on the inverter board 3. The cooling air W cools the switching element 7 and the smoothing capacitor 20 on the inverter board 3 in addition to the reactor 6, and then passes below the upper plate 8 by the inner surface of the housing to the reactor 4 on the PV converter board 2. It is guided toward the center, passes through the smoothing capacitor 19 and the switching element 5, and returns to the blower 12 from above the control boards 10 and 11 to circulate. Since the elements mounted on the control boards 10 and 11 have a small calorific value, the cooling air W which has been warmed by cooling the reactors 6 and 4 is slightly cooled on the control boards 10 and 11 and reaches the blower 12.

By such circulation of the cooling air W, the reactors 6 and 4 and the switching elements 5 and 7 having a particularly large calorific value are cooled. The smoothing capacitors 19 and 20 are also cooled.
With the above-mentioned power conditioner, the following effects can be obtained.

(1) The cooling air W blown from the blower 12 is blown toward the reactor 6 on the inverter board 3 having the largest calorific value. Therefore, the reactor 6 is efficiently cooled by the cooling air W.

(2) The blower 12 is installed on the upper plate 8 and is installed diagonally downward so that the cooling air W faces the reactor 6, and more specifically, the cooling air W directly hits the reactor 6. .. Therefore, the cooling efficiency of the reactor 6 is improved.

(3) The PV converter board 2 and the inverter board 3 on which the reactors 4 and 6 having a large heat generation amount and the switching elements 5 and 7 are mounted are installed on the base plate 1, and the control boards 10 and 11 on which the elements having a small heat generation amount are mounted are mounted. It was installed on the upper plate 8. Therefore, by blowing the cooling air W diagonally downward from the blower 12 installed on the upper plate 8, it is possible to efficiently cool the element having a large calorific value.

(4) By circulating the cooling air W in the housing, the heating elements such as the reactors 4 and 6 and the switching elements 5 and 7 and the smoothing capacitors 19 and 20 can be cooled. Since the smoothing capacitor can be cooled together with the heat generating element, the life of the smoothing capacitor can be extended.

(5) Since the blower 12 is installed so that the lower edge of the blower 12 is located between the upper plate 8 and the base plate 1, the installation height of the blower 12 can be reduced in the housing. Therefore, even in a two-layer structure in which the substrates are separately installed on the base plate 1 and the upper plate 8, it is possible to suppress an increase in the dimensions of the housing in the height direction.

(6) By installing the PV converter board 2, the inverter board 3, and the control boards 10 and 11 separately in two layers, the dimensions of the housing in the plan view direction can be reduced.
(7) As shown in FIG. 4, the center of the fan 14 of the blower 12 is located above the upper plate 8. As a result, the blower 12 can blow the relatively cold air above the upper plate 8 as the cooling air W. Therefore, the cooling efficiency of the reactors 6 and 4, the switching elements 5 and 7, and the smoothing capacitors 19 and 20 is improved.

(8) As shown in FIG. 2, the smoothing capacitor 19 and the switching element 5 on the PV converter substrate 2 are mounted side by side in a direction orthogonal to the direction in which the cooling air W flows. As a result, the cooling efficiency of the smoothing capacitor 19 and the switching element 5 is improved.

The above embodiment may be changed as follows.
-The blower 12 does not necessarily have to blow air diagonally downward toward the reactor 6 as long as the cooling air can be circulated in the housing.

-Elements other than the reactor, switching element, and smoothing capacitor of the power conditioner may be cooled.
-The PV converter board 2 and the inverter board 3 may be configured by a common board.

1 ... Base plate, 2 ... First substrate (PV converter substrate), 3 ... First substrate (inverter substrate), 4, 6 ... Heat generation element (reactor), 5, 7 ... Heat generation element (power semiconductor element, switching element) ), 8 ... Upper plate, 10, 11 ... Second board (control board), 12 ... Blower, 18 ... Heat dissipation fin, 19, 20 ... Smoothing capacitor.

Claims (8)

The first substrate, which is installed on the base plate located in the lower layer in the sealed housing and has multiple elements including heat generating elements, and
A second substrate installed on an upper plate located on the upper layer of the base plate in the housing and mounting a plurality of elements, and
A sealed electronic device provided on the upper plate and provided with a blower that blows cooling air toward the heating element. In the sealed electronic device according to claim 1,
A sealed electronic device in which the blower is installed obliquely downward so that the cooling air is directed toward the heat generating element. In the sealed electronic device according to claim 1 or 2.
A sealed electronic device in which the lower edge of the blower is located between the base plate and the upper plate. In the sealed electronic device according to any one of claims 1 to 3.
The upper plate is a sealed electronic device having a shape that does not cover the upper part of the heat generating element so that the cooling air is directed toward the heat generating element. In the sealed electronic device according to any one of claims 1 to 4.
The heat generating element is a sealed electronic device including at least one of a reactor and a power semiconductor element. In the sealed electronic device according to any one of claims 1 to 4.
A sealed electronic device in which a smoothing capacitor is mounted on the first substrate on a circulation path of cooling air circulating in the housing. In the sealed electronic device according to claim 5 or 6.
A sealed electronic device in which an inverter and a PV converter are mounted on the first substrate, and a control circuit of the inverter and the PV converter is mounted on the second substrate. In the sealed electronic device according to claim 7.
A sealed electronic device having radiating fins on the back surface of the base plate.

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