JP4581175B2 - Air conditioner - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an air conditioner including a converter device that suppresses harmonics and improves power factor by a semiconductor switching element.
[0002]
[Prior art]
A reactor mounting method and a cooling method for a converter device in a conventional air conditioner will be described with reference to FIGS. 1 and 2. FIG. 1 is a simplified circuit diagram of an air conditioner including a converter device that suppresses harmonics and improves a power factor by a conventional semiconductor switching element. FIG. 2 illustrates a reactor mounted state of a converter device in a conventional air conditioner, and is a cross-sectional view of the outdoor unit of the air conditioner as viewed from above.
[0003]
In FIG. 1, 1 is a semiconductor switching element, 2 is a reactor for suppressing harmonics and power factor improvement, 3 is a lead wire for electrically connecting the reactor 2 to the main circuit board 4, 13 is an electric field capacitor, 16 is A diode, 23 is a shunt resistor, and 24 is a gate resistor. In FIG. 2, 5 is a heat dissipating means that is attached to the main circuit board 4 and promotes heat dissipating the heat-generating components mounted on the board, 6 is an outdoor fan, 7 is an outdoor unit, and 8 is an upstream of the outdoor fan 6 in the outdoor unit 7. 9 is an electrical equipment box containing the main circuit board 4 and the reactor 2, 10 is a direct wind from the outdoor fan 6, 11 is a ventilation hole formed in the electrical box, 12 Is a slight wind that flows due to the pressure difference.
[0004]
In the reactor 2 of the power factor improving converter circuit of the air conditioner represented by the simplified circuit diagram of FIG. 1, a large current of up to about 30 A flows by the inverter-driven compressor motor. For this reason, since the size and heat generation amount are large and the weight becomes heavy, the main circuit board 4 cannot be mounted. As shown in FIG. 2, the main circuit on which the electronic components such as the semiconductor switching element 1 and the electric field capacitor 13 are mounted. It was electrically connected to the substrate 4 via the lead wire 3. Further, since it is not connected to the heat radiating means 5 unlike the semiconductor switching element 1, it is naturally cooled in a place where a slight wind 12 flowing due to a pressure difference is obtained by the outdoor fan 6 of the outdoor unit 7 such as near the ventilation hole 11. It was.
[0005]
[Problems to be solved by the invention]
Since the reactor of the converter apparatus in the conventional air conditioner has a large calorific value, it has a structural design restriction that a ventilation path must be secured or placed in a place where ventilation is easily obtained. The outdoor unit of the air conditioner has a configuration in which an outdoor fan 6, a reactor 2, and an electrical box 9 in which the main circuit board 4 is housed are arranged inside the heat exchanger 8 as shown in FIG. 6 is difficult to obtain, and the electric box 9 has a narrow ventilation hole 11 as shown in FIG. 2 in order to minimize the entry of dust and moisture. Only a little flowing air was obtained.
[0006]
Therefore, for devices that require a control device to be built in a small electrical box such as an air conditioner, the size of the reactor is limited and it can only be placed in the immediate vicinity of the ventilation hole. As a result, there was a problem that the temperature of the product increased, parts such as the electric field capacitor on the control board deteriorated, and the product life decreased. Although it may be possible to suppress the temperature rise inside the box by mounting the reactor outside the electrical box, there are problems such as long lead wires, process variations and poor productivity, and high-pressure parts are easily exposed to dust and moisture. there were.
[0007]
Further, since the power factor improving converter device represented by the circuit as shown in FIG. 2 performs PWM control of the semiconductor switching element 1 with a high carrier (about 20 KHz), a current voltage change becomes abrupt and a high-frequency voltage oscillation occurs. This radiates as noise to the space using the circuit loop as an antenna. Therefore, there is a problem that when the lead wire 3 becomes longer, the antenna becomes larger and the amount of noise emitted increases. In particular, when alternative refrigerants such as R407C and R410A, which have a higher pressure than R22, are used, there is a problem that the problem of radiation noise becomes significant because the power input to the compressor increases.
[0008]
This invention was made to solve the above problems, and by dividing the reactor and connecting it in parallel, it was downsized to a size that can be mounted on a board, and the heat dissipating means actively dissipates it. The purpose is to alleviate the structural constraints and suppress the temperature rise in the electrical box. It is another object of the present invention to reduce processing variations and radiation noise by shortening the lead wire or using leadless.
[0009]
[Means for Solving the Problems]
An air conditioner according to the present invention includes at least two or more parallel-connected reactors used for harmonic suppression and power factor improvement, one or more semiconductor switching elements connected to the reactor, and the semiconductor A heat dissipating means for cooling the switching element, and the reactor is disposed in the vicinity of the heat dissipating means, and the space between the reactor and the heat dissipating means is sealed with a resin or gel-like substance having good thermal conductivity and insulation. Thus, a converter device that cools the reactor by the heat radiating means by heat conduction is provided , and an HFC refrigerant or an HC refrigerant that is a refrigerant having a pressure higher than that of R22 is used as the refrigerant.
[0011]
In addition, a resin or gel-like substance having good thermal conductivity and insulation is mixed with a material that improves thermal conductivity .
[0012]
Also, an EMC countermeasure material is mixed into the resin or gel material having good thermal conductivity and insulation .
[0016]
DETAILED DESCRIPTION OF THE INVENTION
The converter device in the air conditioner according to the present invention is configured by dividing the reactor and connecting them in parallel to reduce the individual size to a size that can be mounted on a board, and connecting to the main circuit board in a leadless manner. Enables reduction of processing variation. Furthermore, the heat dissipation of the semiconductor switching element is achieved by enclosing the reactor and a heat conductive substrate having a heat dissipation means on which the semiconductor switching element is mounted with a resin or gel material having good heat conductivity and insulation. The reactor is also cooled using the means. In addition, radiation generated from the circuit loop of the enclosed power factor correction converter device can be obtained by mixing EMC (Electric Magnetic Compatibility) countermeasure materials or materials that improve thermal conductivity into the resin or gel material that encapsulates the reactor. Noise can be reduced and heat dissipation can be improved.
[0017]
Embodiment 1 FIG.
The first embodiment of the present invention will be described below with reference to FIGS. 3, 4, and 5. FIG. The arrangement of the electric box and the outdoor fan in the outdoor unit is the same as that of the conventional apparatus shown in FIG. 2, and the same reference numerals as those of the conventional apparatus indicate the same or corresponding elements, and the description thereof is omitted. . FIG. 3 is an example of a schematic cross-sectional view showing the converter device of the present invention. FIG. 4 shows a simplified circuit diagram of an air conditioner equipped with the converter device of the present invention. FIG. 5 is an assembly view of the converter device of the present invention.
[0018]
As shown in FIG. 3, the semiconductor switching element 1 and the diode 16 of the converter section shown in FIG. 4 are mounted on the heat conductive substrate 14 by soldering, and the heat conductive substrate 14 is used as a bottom to form a box shape. An insulating resin case 17 is formed so that the heat dissipating means 5 and the heat conductive substrate 14 are in close contact with each other by mounting screws 18. The reactor 2 that is divided and downsized to the board mounting size is mounted on the reactor board 19, arranged hierarchically on the upper part of the thermally conductive board 14, and connected to the board by a connecting means such as a bus bar taken out in the vertical direction of the board. 19 is fixed and electrically connected.
[0019]
Further, the space between the heat conductive substrate 14 and the reactor substrate 19 is filled with a resin or gel-like substance 15 having good heat conductivity and insulation, and the heat radiation means 5 can be used to radiate the heat of the reactor 2. . In addition, it is possible to improve thermal conductivity by mixing a filler such as alumina into a resin or gel substance. A control board 21 is arranged on a further upper layer of the reactor board 19, and the semiconductor switching element 1 and the like are mounted and similarly connected by connecting means such as a bus bar and a connector. The uppermost portion is sealed with an insulating resin, and an AC power supply input terminal, an output terminal, and a control interface terminal are attached as external terminals 22.
[0020]
In the control circuit according to the embodiment of the present invention, as shown in FIG. 4, the reactor 2 is divided into four parts, and the semiconductor switching element 1 is also connected to the reactor 2. In an air conditioner with an input current peak of about 30A, if the reactor is divided into four, the current value per unit can be suppressed to a peak of 8A or less, so the reactor can be mounted on a board, and it is a general-purpose mechanical wound reactor. There is also an advantage that even if the number of reactors used increases, the cost can be reduced compared to a single high-current reactor. Furthermore, it is possible to select the number of reactors used for each model with different input current values.
[0021]
Since the semiconductor switching element 1 (MOS-FET) mounted on the heat conductive substrate 14 has few surface mount type general-purpose products for large current exceeding 10A, the input current of 30A peak in FIG. As described above, one or two semiconductor switching elements 1 are provided in parallel for each reactor 2. In addition to the semiconductor switching element 1, the thermally conductive substrate 14 drives a heat-generating component other than the semiconductor switching element 1 such as a shunt resistor 23 for current detection, and the driving of the semiconductor switching element 1 such as a gate resistor 24 and a temperature sensor 25. Also, components that should be placed in the vicinity for protection are also mounted. In the future, if surface-mounted semiconductor switching elements (MOS-FETs) for higher currents will be generalized or semiconductor switching elements such as IGBTs with general-purpose products up to 50A class will be used, semiconductor switching elements will be individually applied to each reactor. The number of elements in the converter section can be reduced, and the semiconductor switching element in the inverter section can be mounted in a vacant space, and all the main circuits of the air conditioner are placed on a thermally conductive board of almost the same size. Can be downsized.
[0022]
As shown in FIG. 5, the reactor substrate 19 is inserted into the box-shaped insulating resin case 17 and then filled with a resin or gel-like substance having good thermal conductivity and insulation. In the case of a gel-like substance, it is also possible to fill the insulating resin case 17 first and insert the reactor substrate 19 later. Further, in the converter device that improves the power factor by the semiconductor switching element 1, since the semiconductor switching element 1 makes the current and voltage change suddenly, high-frequency voltage oscillation occurs, and the circuit loop of the main circuit section shown in FIG. Strong radiated noise is generated as an antenna. The converter device of the present invention is integrated to reduce a circuit loop and suppress radiation noise. Furthermore, radiation noise can be significantly suppressed by mixing EMC countermeasure materials such as ferrite and alumina that have the effect of suppressing radiation noise in the resin or gel-like substance 15 enclosing the reactor 2 and the circuit of the converter unit.
[0023]
The control board 21 disposed above the reactor board 19 includes a circuit for performing PWM control of the semiconductor switching element 1 so as to achieve power factor improvement, harmonic suppression, and an arbitrary bus voltage, and an external control interface circuit. The uppermost external connection terminal and the semiconductor switching element are mounted on a substrate having good thermal conductivity by a bus bar or a connector. In addition, a control circuit may be incorporated on the reactor board without providing a separate control board, so that a converter device having a two-stage configuration of a board having high thermal conductivity and a reactor board can be provided.
[0024]
Further, in the refrigeration cycle in which the compressor 31, the condensation heat exchanger 32, the expansion device 33, and the evaporating heat exchanger 34 shown in FIG. 7 are sequentially connected, a converter / inverter device that controls the drive motor of the compressor 31 is used. When the converter apparatus of this invention is used, it can be set as the refrigerating-cycle apparatus which became low noise and low vibration and reduced radiation noise. In particular, refrigerants used in the refrigeration cycle use refrigerants higher in pressure than R22, such as HFC R410A, R407C, R32, and HC R600A, which do not destroy the ozone layer, compared to conventional HCFC R22 refrigerant that destroys the ozone layer. In this case, the influence of radiation noise increases because the input power to the compressor tends to increase. However, by connecting a plurality of reactors in parallel as in the present invention, the wiring through which the main current such as the lead wire 3 flows It is possible to reduce the length of the converter, reduce radiation noise, and provide a converter device suitable for an alternative refrigerant.
[0025]
Embodiment 2. FIG.
The second embodiment of the present invention will be described below with reference to FIG. FIG. 6 is an example of a schematic cross-sectional view showing the converter device in the air conditioner of the present invention.
[0026]
As shown in FIG. 6, the semiconductor switching element 1, the diode 16, and the reactor 2 that is divided and downsized to the board mounting size are mounted on the heat conductive substrate 14, and the heat conductive substrate 14 is used as a bottom surface in a box shape. An insulating resin case 17 is formed so that the heat dissipating means 5 and the heat conductive substrate 14 are in close contact with each other by mounting screws 18. The heat conductive substrate 14 is filled with a resin or gel-like substance 15 having good heat conductivity and insulation until the reactor 2 is hidden, and the heat radiation means 5 is used to radiate the heat of the reactor 2. Radiation noise can be suppressed by mixing an EMC countermeasure material such as ferrite into the resin or gel-like substance 15 as in the first embodiment. Moreover, the heat dissipation of the reactor 2 is accelerated | stimulated by mixing heat conductive materials, such as an alumina. A control board 21 is arranged above the reactor 2, and the board 21 is fixed and electrically connected by connecting means such as a bus bar taken out in the vertical direction of the board. The uppermost part is hermetically sealed with an insulating resin, and an AC power supply input terminal, an output terminal, and a control interface terminal are attached as the external connection terminals 22, whereby a converter device having the same performance as in the first embodiment can be obtained.
[0027]
【The invention's effect】
As described above, according to the present invention, in a converter device that performs harmonic suppression and power factor improvement using a semiconductor switching element, the reactor used for harmonic suppression and power factor improvement is radiated to cool the semiconductor element and the like. as well as arranged in the vicinity of the unit, to encapsulate by heat conductivity and insulating properties good resin or gel-like substance, a reactor by heat conduction can be cooled by the heat dissipating unit, alleviate the placement constraints of the reactor And the temperature rise of an electrical component box can be suppressed. Further, it is possible to prevent deterioration of the soldering portion of the reactor due to temperature rise.
[0028]
Furthermore, by connecting at least two reactors in parallel, the peak current that flows per reactor can be suppressed, and the size can be mounted on a board and the reactor can be a general-purpose product. It is possible to reduce radiation noise and cost due to the conversion.
[0029]
Moreover, since the material which improves heat conductivity was mixed in the resin and gel-like substance which had favorable heat conductivity and had insulation, the heat dissipation of a reactor can be improved.
[0030]
In addition, by mixing EMC countermeasure material into a resin or gel material having good thermal conductivity and insulation, radiation noise can be significantly suppressed in combination with downsizing of the main circuit.
[0031]
By providing the temperature detecting means on the substrate with good heat dissipation on which the semiconductor element is mounted, it is possible to protect the semiconductor element against thermal destruction.
[0032]
It is arranged in parallel connection on or near the thermally conductive substrate on which the semiconductor element is mounted, and has a reactor used for harmonic suppression and power factor improvement, with the semiconductor switching element, harmonic suppression, In the case of using a converter device that improves the power factor and uses a refrigerant having a pressure higher than R22 as the refrigerant, even if the input power of the compressor increases due to the use of a high-pressure alternative refrigerant, can do.
[Brief description of the drawings]
FIG. 1 is a simplified circuit diagram showing a converter device of a conventional air conditioner.
FIG. 2 is a view of a reactor mounted state of a converter device of a conventional air conditioner as viewed from above the outdoor unit.
FIG. 3 is a schematic cross-sectional view of the converter device according to the first embodiment of the present invention.
FIG. 4 is a simplified circuit diagram of a converter device according to Embodiment 1 of the present invention.
FIG. 5 is an assembly diagram of the converter device according to the first embodiment of the invention.
FIG. 6 is a schematic sectional view of a converter device according to a second embodiment of the present invention.
FIG. 7 is a system conceptual diagram showing a refrigeration cycle apparatus.
[Explanation of symbols]
1. 1. semiconductor switching element; 2. reactor, 3. Lead wire, 4. main circuit board; 5. heat dissipating means; 6. outdoor fan, Outdoor unit, 8. 8. heat exchanger, Electrical box, 10. Direct wind from the fans, 11. Ventilation holes, 12. A slight wind flowing due to pressure difference, 13. Electric field capacitor, 14. A thermally conductive substrate, 15. Resin or gel-like substance, 16. Diode, 17. 17. Insulating resin case Mounting screws, 19. Reactor board, 20. Connecting means, 21. Control board, 22. External terminal, 23. Shunt resistor, 24. Gate resistance, 25. Temperature sensor.

Claims (3)

At least two or more reactors connected in parallel used for harmonic suppression and power factor improvement, one or more semiconductor switching elements connected to the reactor, and heat dissipation means for cooling the semiconductor switching elements And placing the reactor in the vicinity of the heat radiating means, and encapsulating the reactor and the heat radiating means with a resin or a gel-like substance having good thermal conductivity and insulation, so that the reactor is thermally conductive. A converter device for cooling by the heat dissipating means ;
An air conditioner using an HFC refrigerant or an HC refrigerant, which is a refrigerant having a pressure higher than that of R22, as the refrigerant .   The air conditioner according to claim 1, wherein a material that improves thermal conductivity is mixed in the resin or gel substance having good thermal conductivity and insulation.   The air conditioner according to claim 1, wherein an EMC countermeasure material is mixed in the resin or gel substance having good thermal conductivity and insulation.

Images