JP3402326B2 - Inverter power supply - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter application device such as a microwave oven, and an inverter having a heating element such as a magnetron for heating dielectrics such as foods and catalysts using microwaves. The present invention relates to a cooling structure including a structure of a power supply device and a ventilation passage.

[0002]

2. Description of the Related Art In a conventional high frequency heating apparatus equipped with this type of inverter power source, as shown in FIG. 6, an inverter power source 29, a magnetron 30, and an axial flow type cooling fan 31 are individually provided in a main body 28. It is installed. The inverter power supply 29 arranged on the printed circuit board 32 is
Explaining with reference to the circuit diagram shown in FIG. 7, a rectifying circuit 34 for rectifying the electric power obtained from the commercial power source 33, and a control circuit 35.
And a semiconductor switching element 38 that transmits the output power of the rectifier circuit 34 to the resonance circuit 37 via the filter circuit 36 by the output signal of the control circuit 35, and a boosting transformer 39 that boosts and outputs the resonance power of the resonance circuit 37. Then, the magnetron 30 is driven by the high voltage rectification circuit 40 that rectifies the output of the step-up transformer 39 into a DC high voltage and the heater winding 41. Since the inverter power supply 29 handles a high output power, the electric element parts 42 such as the semiconductor switching element 38 which compose the inverter power supply 29 are accompanied by considerably large heat loss, and are forcedly cooled by the cooling fan 31 together with the magnetron 30. There is. At that time, the semiconductor switching element 38 and the rectifier circuit 34 are provided with heat radiating plates 43 and 44, respectively, in order to promote heat radiation, and the cooling fan 31
It is arranged in a part of the ventilation passage 45 of.

[0003]

However, in the above-mentioned conventional configuration, the inverter power supply, the magnetron, and the cooling fan are individually arranged in a wide air passage, so that the required air volume is supplied to all the target cooling components. In order to do so, a large amount of cooling air is required, so that there is a problem that the device cannot be downsized and noise is large.

The present invention solves the above-mentioned conventional problems. The magnetron, the inverter power supply, and the cooling fan are housed in one case to simplify the air passage and cool the main heat-generating components such as semiconductor switching elements. The first purpose is to improve efficiency and reduce noise by reducing the amount of cooling air.

The second purpose is to effectively utilize the space inside the case, to control the inverter power supply and the motor, and to arrange the control parts which do not generate much heat so as not to become the ventilation passage resistance of the cooling fan. It is to improve the air blowing performance and achieve low noise.

[0006]

In order to achieve the above first object, an inverter power supply device of the present invention is an inverter in which a magnetron and electric element parts such as a semiconductor switching element and a step-up transformer are arranged on a main printed board. A power supply, a cooling fan having a centrifugal impeller, and a partition plate for fluidly blocking the intake port and the discharge port of the cooling fan outside the cooling fan are provided in a case having a plurality of suction holes and discharge holes. , One end surface of the cooling fan is the main printed circuit board, the impeller is located above the main printed circuit board,
A scroll-shaped cooling plate having a partially discontinuous portion in cross section is formed around the scroll-shaped cooling plate, and the scroll-shaped cooling plate is a cooling fan.
And the semiconductor switching element is provided on at least one of the outer surface and the inner surface of the cooling plate side surface , and at least the outer surface of the cooling plate side surface or
A fin portion is provided on one of the inner surfaces to obtain a heat transfer area.

In order to achieve the second object, a magnetron, an inverter power source in which electric element parts such as a semiconductor switching element and a step-up transformer are arranged on a main printed circuit board, and a cooling fan having a centrifugal impeller are provided. A partition plate for fluidly blocking the intake port and the discharge port of the cooling fan outside the cooling fan is provided in a case having a plurality of suction holes and discharge holes, and one end surface of the cooling fan is provided with the main print. and substrate, the impeller is located in the main printed circuit board top, constitute a scroll-shaped cooling plate having a cross-section portion discontinuity in its periphery, said
A scroll-shaped cooling plate constitutes the casing of the cooling fan
And, provided with the semiconductor switching element to at least one of outer or inner surface of the cooling plate side, small
At least one of the outer surface and the inner surface of the side surface of the cooling plate is provided with a fin portion to obtain a heat transfer area, and the partition plate is composed of a sub-printed board on which a control component for controlling an inverter power supply or the like is arranged.

[0008]

According to the present invention, the scroll-shaped cooling plate constitutes the casing of the cooling fan with the above-mentioned structure, and the cooling air mainly flows along the wall surface of the cooling plate due to the rotation of the centrifugal impeller. The heat generated by the loss of a rectifying diode or a semiconductor switching element with a large loss attached to the cooling plate is cooled, and the air is sequentially blown from the discontinuous portion to the magnetron or the step-up transformer.

The inverter power supply device of the second invention is
A control component that controls the inverter power supply etc. that was disposed in the cooling fan air passage and does not require much cooling is disposed on a sub printed circuit board different from the main printed circuit board,
It is provided as a partition plate for preventing the recirculation of air in the surface side having the intake port of the cooling fan or in the case, and both printed boards are connected by a conductor portion. As a result, the packaging density of the main printed circuit board is reduced, and the air passage resistance inside the cooling fan is reduced.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 show an inverter power supply device of the first invention, in which an inverter power supply 3 in which an electric component 1 is mounted on a main printed circuit board 2 is a centrifugal type with a magnetron 4 for generating microwaves. It is housed in a conductive case 6 together with a cooling fan 5 having an impeller 9. Inside the case 6, a cooling fan 5 and a main printed circuit board 2 are sequentially joined to the case 6 via a support component 7. The cooling fan 5 penetrates the main printed circuit board 2 and is fixed to the case 6 by a motor 8 and blades. It is composed of a wheel 9, and the impeller 9 is attached to the motor 8 so as to be positioned a few millimeters above the main printed circuit board 2.

Around the impeller 9, there is a tongue portion 10 having a tongue portion 10 and a rectifying diode 11 and a part of the electric element component 1 such as the semiconductor switching element 12 and a partial discontinuity portion 13 in cross section. The cooling plate 14 is provided on the main printed circuit board 2. The cooling plate 14 is made of aluminum or the like, which has excellent heat conduction, and has a configuration capable of extrusion molding in terms of productivity. Therefore, as shown in FIG.
The fin portion 15 can be arbitrarily provided in order to obtain the heat transfer area in the axial direction of the motor 8. An upper plate 17 having an intake port 16 of the cooling fan 5 is provided on the upper surface of the cooling plate 14, and the main printed circuit board 2, the cooling plate 14, and the upper plate 17 serve as the cooling fan 5.
Constitutes the casing of. In order to prevent the recirculation of the air in the case 6, a partition plate 18 which fluidly shuts off the external space of the cooling fan 5 is provided between the intake port 16 and the exhaust port (discontinuous portion) 13. Further, in the case 6, a plurality of suction holes 19 and the partition plate 1 are provided on the intake port 16 side of the partition plate 18.
A plurality of discharge holes 20 are provided closer to the magnetron 4 than 8 is.

In the above structure, the impeller 9 is provided in the case 6.
When is rotated, cooling air enters the case 6 through the plurality of suction holes 19, passes through the intake port 16 of the upper plate 17, the inside of the scroll-shaped cooling plate 14, further cools the magnetron 4 and the step-up transformer 21, and then the plurality of Is discharged to the outside of the case 6 through the discharge hole 20. At that time, since the partition plate 18 blocks the negative pressure region corresponding to the upstream side of the cooling fan 5 and the positive pressure region corresponding to the downstream side of the cooling fan 5 in the case 6, the air (shown by the solid line arrow in the figure) is regenerated. Suction hole 19 without circulation
To the discharge hole 20.

Further, the cooling air first enters the case 6 to cool a part of the outer wall side of the cooling plate 14 and then enters the inside of the cooling plate 14 to accelerate the flow velocity along the inner wall surface of the cooling plate 14. Mainstream flows. Therefore, the heat dissipation area itself of the cooling plate 14 can be configured to be large and useless air can be suppressed. Therefore, cooling is particularly important, and cooling of the rectifying diode 11 and the semiconductor switching element 12 that causes a loss of about 10 W to 70 W when the inverter operates. However, since it is performed efficiently and sufficiently, the amount of cooling air can be reduced to a necessary minimum, and further, the shape of the cooling plate 14 is a scroll shape that matches the casing configuration of the centrifugal fan, and large irregularities inside are also reduced. As a result, the pressure loss in the ventilation passage itself is reduced, and the noise due to the disturbance such as collision is suppressed, so that the overall effect can be significantly reduced.

Next, an embodiment of the inverter power supply device of the second invention will be described. 3 is different from the above embodiment in that a sub-printed circuit board 23 is provided on the surface of the cooling fan 5 having the intake port 22. The sub-printed circuit board 23 is provided with a cooling circuit for controlling the inverter power supply 3 and the motor 8. A control part 24 for a small object such as a resistor or a capacitor that does not require the above is provided, and is connected to the main printed circuit board 25 through a conductor portion 26.

Further, FIG. 4 shows a constitution in which the cooling plate 14 is used as the conductor portion 26, and FIG. 5 shows the sub-printed circuit board 27 as a partition for preventing recirculation in the case 6. With these configurations, the control component 2 mounted on the main printed circuit board 25 facing the inside of the cooling fan 5
4 can be put out of the air passage of the cooling fan 5, the resistance of the air passage can be reduced and the air blowing performance of the cooling fan 5 can be improved. As a result, the rotation speed of the cooling fan 5 can be reduced and the noise during cooling can be reduced. Can be reduced. Also the main printed circuit board 2
The mounting density of No. 5 is reduced, the insulation distance between the high-voltage components can be increased, and the reliability of the inverter power supply when housed in a compact case is significantly improved.

[0017]

As described above, according to the inverter power supply device of the present invention, the following effects can be obtained.

(1) A scroll-shaped cooling plate is provided around a centrifugal impeller provided on the upper part of the main printed circuit board, and a semiconductor switching element having a large loss is attached to the cooling plate. Since most of the air blown by the impeller passes through the wall surface of the cooling plate, the air that does not contribute to cooling is significantly reduced, and both the inside and outside of the cooling plate serve as heat dissipation surfaces, and air with a high flow velocity can be sent to the heat dissipation surface. Effective cooling is performed with a small amount of air, the cooling effect of the semiconductor switching element that is the weakest in terms of heat is significantly improved, and the thermal reliability of the inverter power supply is improved.

(2) Due to the reduction of the cooling air flow and the reduction of the ventilation passage resistance, the ventilation load is reduced and the operating noise during cooling can be greatly reduced. In addition, the motor load can be reduced accordingly, which is advantageous in terms of downsizing of the device and cost.

(3) Further, since the packaging density of the main printed circuit board is reduced, the insulation distance between the high-voltage components provided can be increased, the size of the device can be reduced, and the reliability of the inverter power source can be greatly improved. Be improved.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of an inverter power supply device according to an embodiment of the present invention.

FIG. 2 is a plan view of a main part of the inverter power supply device.

FIG. 3 is a sectional view of an essential part of an inverter power supply device according to another embodiment of the present invention.

FIG. 4 is a cross-sectional view of an essential part of an inverter power supply device according to another embodiment of the present invention.

FIG. 5 is a cross-sectional view of an essential part of an inverter power supply device according to another embodiment of the present invention.

FIG. 6 is a cross-sectional view of an inverter power supply unit of a conventional high frequency heating device.

FIG. 7 is a block diagram showing a circuit configuration of the inverter power supply device.

[Explanation of symbols]

1 Electric element parts 2,25 Main printed circuit board 3 Inverter power supply 4 magnetron 5 cooling fan 6 cases 9 impeller 12 Semiconductor switching element 13 Discontinuous part (outlet) 14 Cooling plate 16 air intake 18 dividers 19 Suction port 20 discharge holes 21 Step-up transformer 22 Inlet 23, 27 Sub printed circuit board 24 Control parts 26 Conductor

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Villa Daisuke 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Yuji Nakabayashi 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. In-house (72) Inventor Makoto Shibuya 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.In-house (72) Inventor Yoshio Ishio, 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. Documents JP-A-4-304168 (JP, A) JP-A-2-269451 (JP, A) JP-A-2-13266 (JP, A) JP-A-63-186550 (JP, A) Actual development Sho-63- 69398 (JP, U) Actually open 62-115772 (JP, U) Actually open 59-28285 (JP, U) Actually open 2-20346 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) H02K 3/28 H05K 7/20

Claims (3)

(57) [Claims] 1. A magnetron, an inverter power source in which electric element parts such as a semiconductor switching element and a step-up transformer are arranged on a main printed circuit board, a cooling fan having a centrifugal impeller, and an intake port and a discharge port of the cooling fan. A partition plate for fluidly blocking the outlet from the outside of the cooling fan is provided in a case having a plurality of suction holes and discharge holes,
One end surface of the cooling fan is used as the main printed circuit board, the impeller is located above the main printed circuit board, and a scroll-shaped cooling plate having a partially discontinuous portion in cross section is formed around the impeller, and the scroll-shaped cooling plate is provided . The cooling plate is
And a semiconductor switching element on at least one of the outer surface and the inner surface of the cooling plate side surface and at least the outer surface of the cooling plate side surface.
In addition, an inverter power supply device is provided with a fin portion to obtain a heat transfer area on one of the inner surfaces . 2. The inverter power supply device according to claim 1, wherein a sub-printed circuit board having control components for controlling an inverter power supply and the like is provided on the surface of the cooling fan having the intake port. 3. A sub-printed board in which the partition plate is provided with a control component for controlling an inverter power supply and the like.
Inverter power supply described.