JP2016027777A - Power conversion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power conversion device that can secure heat radiation of a reactor while securing heat radiation of other heat radiating elements.SOLUTION: A power conversion device has a container having a bottom which is opened at the front surface side thereof. The bottom wall of the container is provided with a first heat radiation part contributing to heat radiation of a reactor which forms a booster circuit directing to the outside of the container, a second heat radiation part contributing to heat radiation of a semiconductor element forming an inverter circuit, and a third heat radiation part contributing to heat radiation of a reactor forming a filter when AC power is obtained. An air channel extending vertically is provided substantially at the center of the outside of the bottom wall, and the first heat radiation and the third heat radiation are configured above the right and left sides of the second heat radiation part at the outside of the bottom wall.SELECTED DRAWING: Figure 3

Description

The present invention relates to a power conversion device that converts DC power output from a solar cell into AC power.

In a conventional power converter, an inverter circuit is configured by connecting a plurality of semiconductor elements (power modules) in a single-phase or multi-phase bridge shape, and these semiconductor elements are periodically turned on / off based on PWM control. To generate AC power. At this time, a semiconductor element (power module) or a reactor through which a large current flows (for example, a DC reactor of a booster circuit or an AC reactor of a filter circuit) generates heat, and thus the power conversion device requires a heat dissipation structure. .

As such a heat dissipation structure, “a container that can be installed on a wall surface for mounting and contains a power conversion unit for performing power conversion between a predetermined power generation apparatus and a commercial power system, A first heat sink and a second heat sink that are spaced apart from each other on both sides of the center line are provided, and the first heat sink corresponds to a first electrical component that generates a relatively large amount of heat. On the other hand, the second heat sink corresponds to the second electric component having a relatively small calorific value. (Patent Document 1).

JP2013-243826A

However, as described in Patent Document 1, in the case of using the first heat sink and the second heat sink separated from each other in the left and right directions, the two electrical components are arranged in descending order of the heat generation amount. When the number of electrical components with large calorific value increased, it was not possible to cope with it sufficiently. In addition, in order to keep the first heat sink and the second sheet sink separated from each other, it is impossible to dispose electric components that generate heat between them, and the number of electric components that generate a relatively large amount of heat generation is limited. It was a thing.

Therefore, the device described in Patent Document 1 is suitable for a power conversion device with a relatively small output or a power conversion device that does not include many electrical components with a large amount of heat generation, and has an output of several KW or more, for example. When a large amount of heat-generating electrical components such as a booster circuit, an inverter circuit, and a high frequency component filter are used in a power converter, it is difficult to cope with the conventional separated structure.

The present invention has been made in view of such problems, and provides a power conversion device that can suppress thermal interference between electrical components when a large number of heat-generating electrical components are housed in a single container. The purpose is to do.

The power conversion device of the present invention has a bottomed container having an open front side, and a first heat radiating portion contributing to heat radiation of a reactor that forms a booster circuit on the bottom wall of the container toward the outside of the container. A second heat radiating portion that contributes to heat radiation of the semiconductor element that forms the inverter circuit, and a third heat radiating portion that contributes to heat radiation of the reactor that forms the filter when obtaining AC power, respectively, It is configured to have an air path extending vertically in the center of the outside of the wall, and the first heat radiating part and the third heat radiating part are configured on the left and right upper sides of the second heat radiating part outside the bottom wall. is there.

The power conversion device of the present invention is capable of suppressing heat interference and ensuring heat dissipation performance when using a plurality of heat generating components.

It is a circuit diagram of the power converter device which shows Example 1. FIG. It is a front view of the power converter device which shows Example 1. FIG. It is the perspective view seen from the bottom wall outer side of the power converter device which shows Example 1. FIG. It is the perspective view seen from the front side of the power converter device which shows Example 2. FIG.

In the present embodiment, by separating the heat radiation of the semiconductor element forming the inverter circuit and the heat radiation of the reactor, it is difficult for the heat of the reactor to be transmitted to the semiconductor element, and the heat radiation of the semiconductor element and the heat radiation of the reactor can be ensured.

As shown in FIG. 1, the power conversion device 1 includes switches 3 a to 3 d, a booster circuit 4, an inverter circuit 5, a filter 6, a grid interconnection relay 7, and a control circuit 9. The DC power output from the plurality of solar cells (panels or strings) 2a to 2d is input via the switches 3a to 3d, and then converted into AC power having a frequency substantially synchronized with the commercial power system 8. Is output. This AC power can be superimposed on the grid 8 or directly supplied to an AC load (not shown).

The DC power output from the solar cells 2a to 2d is collected and input to the booster circuit 4 via the switches 3a to 3d and the backflow prevention diode (not labeled), respectively. Switch 3a ~
3d is a release operation when performing maintenance or the like to open the contact, and solar cells 2a to 2d
The DC power supplied from is cut off.

The booster circuit 4 includes at least a DC reactor DCL, a switch element (MOSFET or IG
A non-insulated chopper circuit is composed of a semiconductor element (BT) 4a, a diode (semiconductor element) 4b, and a capacitor 4c. The booster circuit 4 boosts the input DC power voltage to a desired voltage by controlling the on-duty of the switch element 4a at a predetermined frequency, and outputs the boosted voltage to the inverter circuit 5. This on-duty is controlled so that the DC power output from the solar cells 2a to 2d reaches the maximum or the maximum. MPPT (Maximum Power)
r Point Tracking) operation is controlled.

The inverter circuit 5 includes a circuit in which a plurality of switch elements (semiconductor elements such as MOSFETs and IGBTs) 5a to 5d are connected in a single-phase bridge shape, and these switch elements 5a
˜5d using a modulated wave that substantially synchronizes with system 8 and a carrier wave of a predetermined frequency (P
The DC power is converted into AC power having the same frequency as that of the modulated wave by periodically performing on / off operation while varying the on-duty by ulse width modulation) control. The converted AC power is supplied to an output line L that connects between the inverter circuit 5 and the system 8. Note that the configuration of the inverter circuit 5 is not limited to a single-phase bridge connection, and a neutral point clamp method or the like can be used, and a multi-phase bridge circuit can also be used.

The filter 6 constitutes an L-type filter from the AC reactor ACL and the capacitor 6 a interposed in the output line L, and attenuates high frequency components from the output of the inverter circuit 5.
The AC power from which high-frequency components have been attenuated or substantially removed is superimposed on the system 8 or output to an AC load (not shown) via the grid interconnection relay 7.

The control circuit 9 is composed of a microcomputer or the like, and controls on / off operations of the switch elements of the booster circuit 4 and the inverter circuit 5.

A current flows in the reactor DCL according to the on / off state of the switch element 4a, and a coil (copper wire) and a core (such as an electric iron plate or an electromagnetic steel plate) forming the reactor DCL generate heat according to the amount of the current. For example, in the case where the DC power supplied from the solar cells 2a to 2d is about 5.5 Kw, a heat dissipating unit that uses heat dissipation measures to suppress the heat generation temperature to about 110 degrees is used. The reactor ACL uses a heat dissipating part that continuously generates an output from the inverter circuit 5 and similarly generates heat, and similarly suppresses the heat generation temperature to about 110 degrees. The heat generated from the reactor DCL and the reactor ACL varies depending on the conversion capacity (input capacity and output capacity) of the power converter,
Generally, heat generation increases as the capacity increases, so heat dissipation measures are individually designed according to the heat generation. Further, the heat resistance temperature of the reactor DCL and the reactor ACL is normally about 150 degrees unless a special member or structure is applied.

The inverter circuit 5 includes a switch element (semiconductor element such as MOSFET or IGBT) 5a.
These switch elements are ON / OFF controlled by PWM control, but when they are ON, current flows and heat is generated. The switch elements 5a to 5d are IPM (Intelligent Power Module) together with a diode for controlling the regenerative current and are configured as a single package product, so that the inverter circuit 5 substantially represents the intelligent module IPM. The regenerative control diode similarly generates heat when a regenerative current flows, and the temperature of the switch elements 5a to 5d substantially indicates the temperature of the inverter circuit 5 or the temperature of the intelligent module IPM.

Therefore, the temperature of the switch elements 5a to 5d (intelligent module IPM) constitutes the heat radiating part so as not to exceed about 100 degrees from the protection of the semiconductor. When at least the switch elements 5a to 5d, the reactor DCL, and the reactor ACL are housed in a single container, heat is transferred from the heat radiation portion of the reactor DCL and the reactor ACL to the heat radiation portion of the inverter circuit 5, and the temperature of the inverter circuit 5 is set. Since there is a possibility of exceeding the temperature, the temperature of the heat radiating portion of the reactor DCL and the reactor ACL is suppressed to about 110 degrees so that high-temperature heat is not transmitted to the intelligent module IPM.

FIG. 2 is a front view of the container (housing) 10 (viewed from the opening on the front side), and FIG. 3A is a view of the container 10 viewed from the outside of the bottom wall (side attached to a building or the like). It is a perspective view. FIG.
) Is a perspective view seen from the outside of the bottom wall when the case 40 (described later) is separated from the container 10.

The intelligent module IPM including a plurality of switch elements 5a to 5d and the like of the inverter circuit 5 is directly attached to the second heat radiating portion configured outside the bottom wall 15, and other electronic components are attached to the plurality of substrates 16. Separately mounted and stored in the container 10. Further, the direct current reactor DCL and the alternating current reactor ACL are arranged in cases (corresponding to a heat radiating portion) 40a and 40b that protrude outward from the container 10 (details will be described later).

The container 10 has a substantially rectangular parallelepiped shape, and includes an upper wall 11, a lower wall 12, a left wall 13, a right wall 14,
The bottom wall 15 is formed by drawing a sheet metal, and is attached to the wall surface or gantry of the building with the top wall 11 facing up. Front side configured on the upper wall 11, the lower wall 12, the left wall 13, and the right wall 14 of the container 10 (
The sealing between the container 10 and the front lid is ensured by pressing and closing the packing 19 of the front lid to which the rubber packing 19 is attached at the end on the front side. Also,
A guard G having a plurality of slit-like holes that allow ventilation is attached to the outer periphery of the upper wall 11, the lower wall 12, the left wall 13, and the right wall 14. FIG. 3 shows the guard G for the sake of clarity.
The figure which removed is shown.

An intelligent module IPM (shown by a dotted line in FIG. 2 because it is hidden by the substrate 16) is attached to the center of the bottom wall 15 inside the container 10 through the hole of the bottom wall 15, and this The second heat dissipating part has a plurality of heat dissipating fins F1 and contributes to heat dissipating (cooling) of the intelligent module IPM (heat dissipating part such as a semiconductor element). This fin F1 (second
The heat radiation portion of the intelligent module IPM is formed by forming a plurality of air paths up and down approximately at the center of the outside of the bottom wall 15 with the top wall 11 as the top. It performs heat dissipation (cooling). The air paths at the left and right ends of these air paths are the heat insulation effect against the heat radiation (radiant heat) from the cases 40a and 40b described below and the intelligent module I.
It contributes to both heat dissipation of PM.

Two holes 17a (not shown) and 17b penetrating the bottom wall 15 are provided on the upper left and right sides of the fin F1 (corresponding to the second heat radiating portion) on the outside of the bottom wall 15. Hole 17a on the left wall 13 side (
A case 40a (first heat radiating portion) is provided so as to cover (not shown), and a case 40b (third heat radiating portion) is provided so as to cover the hole 17b on the right wall 14 side. The case 40a houses a direct current reactor DCL that forms the booster circuit 4, and the case 40b houses an alternating current reactor ACL that forms the filter 6. By configuring the cases 40a, 40b on the upper side of the bottom wall 15, the amount of heat transmitted from the cases 40a, 40b to the fins F1 (second heat radiating portion) is suppressed.

Switches 3a to 3d are arranged below the reactor DCL on the left wall 13 side of the bottom wall 15 of the container 10, and a terminal for outputting AC power to the lower side of the reactor ACL on the right wall 14 side of the bottom wall 15 21
Is arranged.

Next, a specific arrangement of the AC reactor ACL will be described. The direct current reactor DCL is disposed in the same manner as the alternating current reactor ACL, and thus the description thereof is omitted.

The AC reactor ACL is attached to the case 40b by screwing or the like. The case 40b has a substantially rectangular parallelepiped shape having an opening. After the AC reactor ACL is received from the opening H and the AC reactor ACL is screwed to the case 40b, the case 40b
The inside is filled with a resin having good thermal conductivity. A plurality of fins F2 may be provided outside the case 40b, and the heat generated by the reactor is resin, the case 40b, and the fins F2.
The heat is dissipated through

A plate-shaped attachment member 30 is disposed between the case 40 b and the container 10. Mounting member 3
0 covers the opening of the case 40b and is attached to the container 10 together with the case 40b by screws. Between the case 40b and the mounting member 30, a first packing 33 made of rubber such as silicon rubber having a low thermal conductivity and a heat insulation property of about 1 mm in thickness is sandwiched.

The mounting member 30 has a circular hole 32 for passing the wiring of the AC reactor ACL (output line L).
A protrusion 36 (spacer) is formed around the hole 32 so as to protrude about 5 mm from the case 40b to the container 10 side. A rib 37 higher than the convex portion 36 is formed on the inner edge of the convex portion 36.

When the mounting member 30 is disposed in the container 10, the rib 37 is fitted into the hole 17b, and the mounting member 30 is positioned. In addition, a second packing 34 made of rubber such as silicon rubber having a low thermal conductivity and having a thickness of about 1 mm is interposed between the convex portion 36 and the container 10. In addition, the convex part 36 (spacer) may be provided in the container 10 side, and may be provided by another member.

Thus, in this embodiment, the clearance S (air insulation layer) of about 5 mm to 6 mm is formed between the container 10 and the mounting member 30 (case 40b) by the convex portion 36 and the second packing 34 (FIG. Therefore, the heat insulation effect by air is obtained between the container 10 and the case 40b. Therefore, the heat of the AC reactor ACL becomes difficult to be transmitted to other heat radiating elements (for example, a switch element constituting the inverter circuit), and heat radiation of the other heat radiating elements can be ensured. Moreover, the heat radiation of AC reactor ACL is ensured from fin F2 of case 40b.

The attachment member 30 is disposed between the case 40b and the container 10, and the case 40b and the attachment member 30 are disposed.
Since the first packing 33 and the second packing 34 are disposed between the mounting member 30 and the container, respectively, the case 40b and the container can be sealed to improve waterproofness.

Moreover, in this embodiment, since AC reactor ACL is attached to case 40b,
The heat of the AC reactor ACL becomes difficult to be transferred to the container 10 due to the heat insulation effect of the gap S, and the portion of the container 10 to which the intelligent module IPM is attached becomes the AC reactor ACL.
As a result, the heat of the intelligent module IPM is secured.

Therefore, the heat dissipation (cooling) capability of the case 40b is suppressed, and the reactor temperature is 150.
Even if it is configured so as to be close to the temperature (the amount of heat radiation for the reactor ACL is reduced), the heat generated by the reactor ACL is prevented from being directly transmitted to the fin F1 (intelligent module IPM) through the bottom wall 15 of the container 10. , FinM intelligent module IPM
The temperature rise due to the heat radiation of the reactor of the intelligent module IPM is suppressed by securing the heat radiation amount.
In other words, the thermal interference between the reactor and the intelligent module IPM (semiconductor element, etc.) due to the heat radiation temperature is suppressed, the degree of freedom in setting each temperature is increased, and the configuration mainly consists of cooling the intelligent module IPM in a limited space. It becomes possible.

Moreover, in this embodiment, although the convex part 36 provided in case 40b touches the container 10, this contact area is small, and there is substantially no influence of the heat | fever of AC reactor ACL transmitted to the container 10. FIG. A heat insulating packing may be provided.

Further, in the present embodiment, the heat insulation layer is provided while the case 40b and the container 10 face each other to provide heat insulation. However, a heat insulation member may be disposed on the air heat insulation layer, or the attachment member. 30 may be a member having a heat insulating property.

In the first embodiment, the case 40 a and the case 40 b are placed outside the bottom wall 15 with the attachment member 30 and the first.
Although it attached via the packing 33 and the 2nd packing 34, as shown in FIG. 4, you may use the case 50 attached to the inner side of the bottom wall 15 (inner side of the container 10). In the description, the case on the DC reactor DCL side will be described for the sake of simplicity, but the same configuration can be adopted for the case on the AC reactor ACL side.

The case 50 has a flange 51 formed in the opening, and unlike the cases 40a and 40b of the first embodiment, the fin F2 is not formed on the outside of the case 50. The case 50 is made of a metallic member, a DC reactor DCL is screwed in the case, and the case 50 is filled with a resin having good thermal conductivity. Thereby, the heat of reactor DCL is transferred to case 50 through the resin and is radiated from case 50. That is, the case 50 does not have the fins F2, but functions as a heat radiating material in the same manner as the case 40a and the case 40b.

The case 50 is attached by sandwiching a rubber packing 53 such as silicon rubber having a low thermal conductivity and a heat insulation property having a thickness of about 1 mm between the flange 51 and the inside of the bottom wall 15. A hole through which a screw is passed is formed in the flange 51 and the third packing of the case 50, and the case 50 is screwed through the screw hole and fixed to the bottom wall 15. A lid 52 is attached to the opening side of the case 50.

Even if comprised in this way, it becomes difficult for the heat | fever of a reactor to be transmitted to the container 10 by the heat insulation effect between the case 50 and the container 10, and the part of the container 10 in which intelligent module IPM is attached influences the heat_generation | fever of AC reactor ACL. It becomes difficult to receive and heat dissipation of the intelligent module IPM is secured.

As mentioned above, although one Embodiment of this invention was described, the above description is for making an understanding of this invention easy, and does not limit this invention. It goes without saying that the present invention can be changed and improved without departing from the gist thereof, and that the present invention includes equivalents thereof.

The power conversion device 1 of the present embodiment can also be used as a power conversion system including a DC power source such as solar cells 2a to 2d.

DESCRIPTION OF SYMBOLS 1 Power converter 2a-2d Solar cell 3a-3d Switch 4 Booster circuit 5 Inverter circuit 6 Filter 7 Relay 8 System 9 Control circuit 10 Container 11 Upper wall 12 Lower wall 13 Left wall 14 Right wall 15 Bottom wall 16 Substrate 17a Hole 17b hole 19 packing 21 terminal 30 mounting member 32 hole 33 first packing 34 second packing 36 convex portion 37 rib 40a case 40b case 50 case 51 flange 52 lid 53 packing IPM intelligent module F1, F2 fin L output line G guard H opening S clearance

Claims (5)

In a power conversion device that boosts DC power output from a solar cell with a booster circuit and then converts it into AC power having the same frequency as the system using an inverter circuit, it has a bottomed container with an opening on the front side. A first heat dissipating part that contributes to heat radiation of the reactor that forms the step-up circuit toward the outside of the container on the bottom wall of the container, a second heat dissipating part that contributes to heat radiation of the semiconductor element that forms the inverter circuit, And a third heat dissipating part that contributes to heat dissipating the reactor that forms the filter for obtaining the AC power, and the second heat dissipating part is configured to have an air passage extending vertically at the substantially center outside the bottom wall. And a first heat radiating portion and a third heat radiating portion are formed on the left and right upper sides of the second heat radiating portion outside the bottom wall. 2. At least one of the first heat radiating part and the third heat radiating part is configured separately from the container, and each reactor is accommodated through a hole formed in the container. The power converter device described in 1. 3. The electric power according to claim 2, wherein at least one of the first heat radiating portion and the third heat radiating portion is attached to the container via a member that contributes to heat insulation with the container. Conversion device. At least one of the first heat radiating portion and the third heat radiating portion is attached to the outside of the bottom wall via the bottom wall and the attachment member, and an air layer is provided between the attachment member and the bottom wall. The power converter according to claim 2, wherein the power converter is provided. At least one of the first heat radiating portion and the third heat radiating portion is provided with a flange at the opening of the case, and is attached between the flange and the bottom wall via a member that contributes to the heat insulation. The power conversion device according to claim 3.

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