JP6550858B2 - Power converter - Google Patents

Description

  The present invention relates to a power converter.

  In a power conversion device in which a semiconductor module for controlling a large power such as an IGBT (Insulated Gate Bipolar Transistor) or a balance resistor is mounted on a circuit board, various cooling structures are used to prevent the influence of heat generated from these electronic components. It has been subjected. For example, in Patent Document 1, the inside of the housing is cooled by forming a vent hole in the housing that houses the circuit board. According to this power conversion device, since ventilation is performed between the inside and outside of the housing through the ventilation hole, it is possible to prevent the inside of the housing from being maintained at a high temperature.

JP 2008-92632 A

  When the ventilation hole is provided in the housing, natural convection can be used, and therefore it is preferable to provide the ventilation hole on the upper surface of the housing. However, in the power conversion device in which the upper surface of the housing is provided with a vent hole, not only dust can easily enter the inside of the housing, but also a foreign object having a relatively large shape may enter. Therefore, in a power conversion device having a vent on the top surface of the housing, it is extremely important how to prevent the influence on the electronic components due to the entry of foreign matter when cooling the inside of the housing. It becomes.

  In view of the above circumstances, an object of the present invention is to provide a power conversion device capable of cooling the inside of a housing without causing an influence on an electronic component due to entry of a foreign substance.

  In order to achieve the above object, a power converter according to the present invention has a circuit board on which electronic components constituting a plurality of capacitors and a control circuit are mounted, a vent hole on an upper surface, and the circuit board is accommodated therein. A power conversion device including a housing, on a mounting surface of the circuit board, above the electronic components constituting the control circuit, and in a region that is a lower region of a vent hole provided on the upper surface of the housing The capacitor is mounted.

  In the power converter described above, the present invention is characterized in that the capacitor is mounted on the upper edge of the mounting surface of the circuit board.

  In the power converter described above, the capacitor is connected in series between a pair of power supply lines that supply a power supply voltage to the inverter circuit, and the capacitor includes the pair of power supplies. Balance resistors connected in series between the lines are connected in parallel to each other, and the balance resistor is an air passage region configured inside the casing by mounting the capacitor on the circuit board. Implemented in the

  In the power converter described above, the present invention is characterized in that two or more sets of capacitors having different mounting heights are mounted on the circuit board.

  According to the present invention, since the capacitor is mounted above the electronic component for configuring the control circuit, even if a foreign object enters from the vent hole provided on the upper surface of the housing, the capacitor further moves downward. Entry is blocked. For this reason, according to this power converter, it is possible to cool the inside of the housing efficiently without fear of affecting the electronic components.

FIG. 1 is a perspective view showing a state in which a circuit board is accommodated in a case in a power conversion device according to an embodiment of the present invention. FIG. 2 is a cross-sectional side view of the power conversion device shown in FIG. FIG. 3 is a plan view of the power conversion device shown in FIG. FIG. 4 is a circuit diagram of the power conversion device shown in FIG. FIG. 5 is a view schematically showing the inside of a case in the power conversion device shown in FIG. FIG. 6 is a view schematically showing the inside of a housing in the first modification of the power conversion device shown in FIG. FIG. 7 is a view schematically showing the inside of a housing in the second modification of the power conversion device shown in FIG. FIG. 8 is a view schematically showing the inside of a housing in the third modification of the power conversion device shown in FIG. FIG. 9 is a view schematically showing the inside of a housing in the fourth modification of the power conversion device shown in FIG. FIG. 10 is a view schematically showing the inside of a housing in the fifth modification of the power conversion device shown in FIG.

  Hereinafter, preferred embodiments of a power conversion device according to the present invention will be described in detail with reference to the attached drawings.

  FIG.1, FIG.2, FIG.3 shows the power converter device which is embodiment of this invention. As shown in the circuit diagram of FIG. 4, the power converter exemplified here outputs AC power to a load 1 such as an induction motor or a synchronous motor. A converter circuit 2 and an inverter are provided on a flat circuit board 10. A circuit 3 and a control circuit 4 are provided. The converter circuit 2 converts an AC voltage input from a power supply 5 such as a commercial power supply into a DC voltage. The inverter circuit 3 converts the DC voltage converted by the converter circuit 2 into an AC voltage. The control circuit 4 is for outputting a drive control signal to the inverter circuit 3.

  Between a pair of power supply lines 6 that supply power supply voltage from the converter circuit 2 to the inverter circuit 3, a plurality of capacitors 7 are connected in series, and a resistor 8 is connected in series. The capacitor 7 is for smoothing the output voltage from the converter circuit 2. The resistors 8 are connected in parallel to the capacitors 7 and function as balance resistors so that the voltages applied to the individual capacitors 7 are equal.

  As shown in FIGS. 1, 2 and 3, the circuit board 10 described above is housed inside the housing 20. The housing 20 includes a frame body 21, a peripheral wall body 22, and a front wall body 23 that are molded from resin, sheet metal, aluminum die casting, or the like.

  Although not explicitly shown in the drawing, the frame body 21 has a box shape in which the upper surface 21a, the lower surface 21b, and the rear surface 21c are opened. The rear surface 21c of the frame body 21 is formed in a flat shape and serves as an attachment surface when attached to the support plate B along the vertical direction of a switchboard or the like. On the front surface of the frame body 21, bosses 21d are provided at appropriate places. The boss portion 21 d is a portion erected from the front surface of the frame body 21, and is located on the same plane in which each protruding end surface is substantially parallel to the front surface of the frame body 21. The boss portion 21d is supported by the circuit board 10 so as to be parallel to the front surface of the frame body 21 by screwing a screw s in a state where the rear surface 10r of the circuit board 10 is in contact with the protruding end surface. is there. A heat sink 30 and a cooling fan 40 are disposed inside the frame body 21. The heat sink 30 is for cooling the IGBT module 11 mounted on the back surface 10 r of the circuit board 10. The cooling fan 40 ventilates the heat sink 30.

  The peripheral wall body 22 is provided so as to surround the circuit board 10 supported on the front surface of the frame body 21. In the present embodiment, the peripheral wall body 22 is configured to include an upper wall portion 22a, left and right side wall portions 22b, and a bottom wall portion 22c. Ventilation holes 22 d are provided in the upper wall 22 a and the bottom wall 22 c of the peripheral wall 22. The vent hole 22d is a notch formed so as to penetrate the peripheral wall body 22, and as shown in FIG. 3, the upper wall portion 22a and the bottom wall portion 22c are on the front side of the surface (mounting surface) 10f of the circuit board 10. It forms in the part which becomes. As is clear from the figure, the vent hole 22d of the upper wall portion 22a is formed in a portion that is almost the entire region in the width direction.

  As shown in FIG. 2, the front wall body 23 has a size that covers the entire front surface of the peripheral wall body 22, and is disposed so as to be detachable from the peripheral wall body 22. When the front wall body 23 is attached to the support plate B via the frame body 21, the front wall body 23 becomes the front surface of the power conversion device. Although not clearly shown in the figure, the front wall 23 is provided with an interface such as an operation unit and a display unit.

  As shown in FIGS. 1 and 5, the circuit board 10 accommodated in the housing 20 configured as described above includes the above-described capacitor 7, resistor 8, and electronic component 12 such as an IC chip constituting the control circuit 4. It has been implemented. Capacitor 7 has a cylindrical shape with a relatively large diameter, and two sets having different mounting heights are the surface 10f of circuit board 10, that is, the upper edge of the same surface as the surface on which electronic component 12 is mounted. Are located in the A capacitor having a large mounting height (hereinafter referred to as “high capacitor 7H”) and a capacitor having a mounting height smaller than that of the high capacitor 7H (hereinafter referred to as “low capacitor 7L”) are both upper wall portions 22a of the peripheral wall body 22. In the above, the dimensions are such as to project forward than the position where the vent holes 22d are provided. In FIG. 5, for convenience, the high capacitor 7H is drawn with a double circle, and the low capacitor 7L is drawn with a single circle. That is, in the embodiment, two high capacitors 7H are arranged side by side right and left at a position corresponding to the center of the upper wall 22a at the upper edge of the circuit board 10, and both sides of the high capacitor 7H Low capacitors 7L are disposed at positions below the lower side. On the surface below the capacitors 7H and 7L in the circuit board 10, the electronic component 12 constituting the control circuit 4 is mounted. The resistor 8 that functions as a balance resistor has a large amount of heat generation, and is therefore disposed in an air passage region from the vent hole 22d of the bottom wall portion 22c to the vent hole 22d of the upper wall portion 22a. In the present embodiment, as described above, the high capacitor 7H is disposed in the central portion at the upper edge of the circuit board 10, and the low capacitor 7L is disposed on both sides thereof. The air taken in from 22d collides with the high condenser 7H and branches left and right, passes through the gap between the low condenser 7L and the inner surface of the front wall 23 and passes through the air hole 22d of the upper wall 22a to the outside Will be discharged (arrow A in FIG. 5). Therefore, the resistors 8 are respectively disposed in a portion immediately below the high capacitor 7H and in a portion immediately above the low capacitor 7L. In the present embodiment, the converter circuit 2, the inverter circuit 3, and the control circuit 4 are mounted on the circuit board 10. However, it is sufficient that at least the capacitor 7 and the control circuit 4 are mounted on the circuit board 10. The converter circuit 2 and the inverter circuit 3 may be mounted on a circuit board different from the circuit board 10.

  In the power conversion device configured as described above, when heat is generated inside the housing 20 during operation, the heat is exhausted to the outside from the vent hole 22d of the upper wall portion 22a by natural convection, while the bottom wall portion. Outside air is drawn into the inside of the housing 20 from the vent 22 d of 22 c. Therefore, there is no case where the inside of the housing 20 is maintained at a high temperature. In particular, since the resistor 8 which is in a high temperature state is disposed in the air passage area, cooling can be efficiently achieved. In addition, according to this power converter, since the high capacitor 7H and the low capacitor 7L are arranged in the lower region of the vent hole 22d provided in the upper wall portion 22a, the metal made of a screw, a wire or the like is temporarily provided from the vent hole 22d. Even if the foreign matter enters, there is no possibility of affecting the electronic component 12 mounted below these capacitors 7H and 7L.

  In addition, the arrangement | positioning aspect of the capacitor | condenser 7 and the resistor 8 is not restricted to embodiment, It can change suitably like the modification shown in FIGS.

  That is, in the first modification shown in FIG. 6, the high capacitor 7 </ b> H is arranged at the corners at the upper edge of the circuit board 10. The low capacitor 7L is a portion slightly lower than the high capacitor 7H at a center position of the high capacitor 7H. When the capacitors 7H and 7L are arranged in this way, the air sucked from the vent hole 22d of the bottom wall portion 22c avoids the high capacitor 7H and passes through the central portion where the low capacitor 7L is arranged to pass through the upper wall. The air is discharged to the outside from the vent holes 22d of the portion 22a (arrow A in FIG. 6). Therefore, the resistor 8 is disposed only in the portion immediately above the low capacitor 7L.

  In the second modification shown in FIG. 7, high capacitors 7 H are disposed at the upper edge of the circuit board 10 at a distance from each other. The low capacitors 7L are disposed at the lower right portions of the respective high capacitors 7H in FIG. When the capacitors 7H and 7L are arranged in this way, the air sucked from the vent hole 22d of the bottom wall portion 22c avoids the high capacitor 7H and the portion where the low capacitor 7L is arranged as in the first modification. It passes through and is discharged | emitted from the vent hole 22d of the upper wall part 22a outside (arrow A in FIG. 7). Therefore, the resistor 8 is disposed only in the portion immediately above the low capacitor 7L.

  In all of Modification 3, Modification 4, and Modification 5 shown in FIGS. 8 to 10, a high capacitor 7 </ b> H and a low capacitor 7 </ b> L are arranged in parallel along the upper edge of the circuit board 10. In the third modification shown in FIG. 8, the high capacitor 7H is disposed at the center, and the low capacitors 7L are disposed at both corners. In the modification 4 shown in FIG. 9, the low capacitor 7L is arrange | positioned in the center contrary to the modification 3, and the high capacitor 7H is arrange | positioned at both corners. In the fifth modification shown in FIG. 10, high capacitors 7H and low capacitors 7L are alternately arranged. In these modified examples, the air sucked from the vent hole 22d of the bottom wall portion 22c avoids the high capacitor 7H, passes through the portion where the low capacitor 7L is disposed, and passes through the vent hole 22d of the upper wall portion 22a to the outside. Will be discharged (arrow A in each figure). Therefore, the resistor 8 is disposed only in a portion immediately below the low capacitor 7L.

  In the above-described embodiment and Modifications 1 to 5, the capacitor 7 is mounted on the upper edge portion of the surface 10f of the circuit board 10. However, in the surface 10f of the circuit board 10, The upper edge is not necessarily required as long as it is a portion that is above the electronic component 12 that constitutes the control circuit 4 and that is a lower region of the vent hole 22d of the housing 20.

  In the above-described embodiment and Modifications 3 to 5, the resistor 8 is mounted on the upstream side of the condenser 7 with respect to the ventilation. However, the influence of heat on the capacitor 7 is taken into consideration. In this case, it is preferable that the resistor 8 is arranged at a site on the downstream side of the ventilation with respect to the capacitor 7 as in Modification 1 and Modification 2. In addition, since the capacitors 7H and 7L having different mounting heights are mounted as the capacitor 7, it is possible to arbitrarily set the air passage area inside the housing. It is not limited to.

  Further, in the above-described embodiment, air is sucked into the housing 20 through the air holes 22d provided in the bottom wall portion 22c of the housing 20, but in the side wall portion 22b of the housing 20 A vent for suction may be provided at the lower position. In this case, the vents need not be provided in the two side walls, but it is sufficient if they are provided in one of the side walls.

  In the above-described embodiment, four capacitors 7 are mounted on the circuit board 10, but the number of capacitors 7 may be two or more. Further, the plurality of capacitors 7 need not be connected in series, and two or more capacitors 7 may be connected in parallel or may be connected in series-parallel. In addition, three or more sets of capacitors 7 having different mounting heights may be appropriately disposed on the circuit board.

DESCRIPTION OF SYMBOLS 3 inverter circuit 4 control circuit 5 power supply 6 power supply line 7 capacitor 8 resistance 10 circuit board 10f surface 12 electronic components 20 housing | casing 22a upper wall part 22d air vent

Claims (4)

A circuit board mounted with electronic components constituting a plurality of capacitors and a control circuit, and a accommodating the circuit board in the internal housing, the upper wall portion constituting the upper surface of said housing, said housing A power conversion device provided with a vent hole that communicates the inside and the outside of
Wherein the site electronic components above and ing than constituting the control circuit in the mounting surface of the circuit board, and mounting the plurality of capacitors to parallel only along the left-right direction, the upper wall of the housing The whole area under the vent hole provided in the part is covered with the plurality of capacitors .   The power conversion device according to claim 1, wherein the capacitor is mounted on a portion which becomes an upper edge in a mounting surface of the circuit board. The capacitor is connected in series between a pair of power supply lines for supplying a power supply voltage to the inverter circuit,
Balance resistors connected in series between the pair of power supply lines are connected in parallel to the capacitors, respectively.
The power converter according to claim 1, wherein the balance resistor is mounted in an air passage region configured in the housing by mounting the capacitor on the circuit board.   4. The power conversion device according to claim 1, wherein two or more sets of capacitors having different mounting heights are mounted on the circuit board. 5.

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