JPH02140577A - Cold storage refrigerator - Google Patents

Abstract

PURPOSE:To perform variable control of the rotation speed of a compressor motor in a refrigerating cycle by a method wherein wiring, resistances and semiconductors, except energy accumulation passive elements having so large capacity that it is impossible to integrate them into an integrated circuit, are integrated into a monolithic integrated circuit which is formed on a substrate together with a signal control circuit that controls the rotating speed of the compressor motor according to changes in the temperature in a compartment. CONSTITUTION:A power transformer 1, a compressor temperature detector 4 of a signal controller 48 are enclosed in a metallic box 10. A power source line 51 that connects to a commercial power source, and a signal line 52 that connects to a microcomputer 8 of the signal controller 48 are output as outside connection lines. The signal line 51 outputs a speed instruction and a start instruction of a compressor motor 2 by which rotation speed control is carried out so as to increase the rotating speed of the compressor motor 2 when the temperature in a compartment increases, and to reduce it when the temperature in the compartment decreases. In case the capacity of the signal controller 48 is small, it can be enclosed in the metallic box 10 as it can be integrated into a monolithic integrated circuit.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a refrigerator operation control device, and particularly to a cooling device control device and a device suitable for variable control of the rotation speed of a compressor motor in a refrigeration cycle. It concerns the implementation method.

[Prior art] Conventional refrigerators generally use an induction motor that generates only a constant number of rotations to drive the compressor, so it is not possible to obtain a cooling capacity that corresponds to the temperature load, and the temperature load is large. In this case, it takes a long time to reach the target temperature, making it difficult to cool down. On the other hand, when the temperature load is small, the cooling capacity exceeds the required level, resulting in undershoot from the target temperature and frequent intermittent operation, resulting in large temperature fluctuations and wasted power consumption. In order to improve this, a drive circuit that can control the compressor rotation speed as disclosed in Japanese Patent Application Laid-Open No. 61-070:163 is provided, and when the temperature load is human, the rotation speed of the compression equipment is maximized. When the temperature load is small, a system has emerged that controls the rotation speed to a small level according to the temperature load.

The control circuit for this compressor motor rectifies the commercial power supply,
It is composed of a bridge type inverter using transistors, and a commutation signal is applied to the transistors by a microcomputer to control the rotation speed of the motor in the compressor. Conventionally, these control circuits have been constructed using individual semiconductor elements on a wiring board.

[Problems to be Solved by the Invention] The first problem is that this wiring board circuit is a so-called power type circuit that handles commercial power, so it is relatively large and heat radiation must be taken into consideration.

As described in Japanese Patent Application Laid-Open No. 61-213592, this control circuit that can control the rotation speed of the compressor is placed on the top of the refrigerator, and is connected to the compressor located at the bottom of the refrigerator via multiple wires. Ta.

Therefore, there is a second problem in that the wiring connection work becomes complicated and noise increases due to the mutual inductance and stray capacitance between the wirings.

In addition, this type of refrigerator that can control capacity uses an electric motor that can continuously control the rotation speed to drive the compressor, so there is a circuit that detects the difference between the target temperature and the actual temperature as a temperature load. When the temperature load is large, the quick freezing command increases the cooling capacity of the compressor to the maximum rotation speed, and when the temperature load is small, the temperature load detection means increases the cooling capacity according to the temperature load. Appropriate cooling capacity is obtained by controlling the number of

However, as shown in FIG. 8, in actual refrigerators, in addition to the freezing compartment 38 and the refrigerator compartment 39, there are an increasing number of foods that have various storage temperatures specified, such as a chilled storage compartment 41, frozen storage water 40, and vegetable compartment 42. In these storage compartments, one compressor 3 circulates the refrigerant in a refrigeration cycle 44, and a fan motor 43 in the freezer compartment sends cold air 47 as indicated by the arrow to each storage compartment.Therefore, each storage compartment , are connected by a cold air ventilation path,
The temperature of each storage chamber is controlled by a damper 46 or the like. Therefore, the temperature in each storage room not only has a temperature range of about 3℃ relative to the desired temperature, but also when the door is opened and closed, the internal temperature rises, and it takes a long time to stabilize at the set temperature. This caused problems in food preservation. Another drawback was that the odor of vegetables stored in the vegetable compartment reached the freezer compartment, resulting in the odor of vegetables being attached to the ice. Furthermore, when defrosting, the speed of frosting on the evaporator changes depending on the rotation speed of the compressor motor, so the amount of frosting per given operating time is not always constant. The third problem was that the moisture spread throughout the refrigerator from the cold air ventilation ducts, making it easy for frost to form.

[Means for Solving the Problems] The first of the above problems is the large capacity energy storage structure that cannot be integrated into an integrated circuit for the power converter for a compressor using a commercial power source as a drive source! The wiring, resistor, and semiconductor section excluding the '/J element are made into a monolithic integrated circuit, and formed on a circuit board together with a signal control section that controls the rotation speed of the compressor motor according to changes in the temperature inside the refrigerator. This monolithic integrated circuit is a special integrated circuit that has a high breakdown voltage using dielectric isolation, and this technology has been established in recent years. Compared to pn junction isolation technology, this dielectric isolation technology allows for more complete isolation between elements using the vI dielectric, and even when the voltage is increased, latch-up FT
1. This invention is suitable for the power conversion section of a compressor motor of several hundreds of volts using a commercial power source as a body motion source. Therefore, the board area of the power conversion section can be significantly reduced, and the power conversion section can be formed on a circuit board together with the signal control section or alone to reduce the size of the circuit, and the board can be housed in a small metal box. It was resolved by doing this.

In addition, when converting the power oscillating part into a monolithic structure,
In order to configure a power semiconductor element on a chip of several mm square,
Technology is needed to minimize element loss and suppress heat generation. Further, in order to improve the efficiency of power semiconductor elements, elements such as MO3F[ET, IC; BT, etc. are used, but a power source is required to drive these elements. Therefore, it is necessary to generate power using a circuit within the chip and reduce the amount of power supplied from the outside.

This control device is connected to a winding of a compressor motor, and this winding is connected to the external control device via a sealed terminal of the compressor. Therefore, a terminal is also provided in the metal box in which the control device is housed so that the control device can be directly attached to the sealed terminal of the compressor with a plug-in type. Therefore, conventionally the compressor and the control device were connected by a plurality of wires, but this wire can be eliminated.

In addition, when detecting the temperature of the compressor, a temperature detector is provided in the control device, and the control device is attached to the compressor directly, so that the temperature sensor directly detects the temperature of the compressor itself. This eliminates the need for wiring to exposed elements such as thermistors, which were conventionally used, and the second problem mentioned above is reduced to M,/1'1.

In addition, in the storage room, the actual temperature has a temperature range of about ±2℃ compared to the set temperature, and the internal temperature rises when the door is opened and closed, and it takes time to stabilize at the set temperature. By making each storage room or storage room with a relatively equal internal temperature independent, each storage room is equipped with a small compressor, and the temperature is controlled independently, making it easy to control the temperature of each storage room. Become. At this time, the control device may be provided in each storage chamber in pairs with the compressor, or one control device may control the compressor provided in each storage chamber. As the compressor becomes smaller, the speed of the compressor motor is increased to increase the output.

Furthermore, the problem of vegetable odor on the ice in the freezer compartment can be solved by making the vegetable compartment independent and completely shutting it off from the freezer compartment to control the temperature. As for frosting on the evaporator installed in each storage room, as mentioned above, by controlling the temperature of only the vegetable compartment independently, the moisture in the vegetable compartment does not move to other storage rooms, so frosting on the evaporator does not occur. is reduced, and the defrosting time is shortened to 1111i. The third problem can also be solved by the above.

[Objective] The object of the present invention is to provide a multi-chamber refrigerator while solving the first, second, and third problems mentioned above.

[Function] In the present invention, first, the wiring, resistors, and semiconductor parts, except for the large-capacity energy storage passive elements that cannot be integrated into an integrated circuit, of the power conversion section for a compressor that uses a commercial power source as a drive source, are dielectrically connected. By using the body separation method to create a monolithic integrated circuit, we can significantly reduce the board area and miniaturize the circuit. In addition, in refrigerators, by increasing the maximum rotation speed of the variable speed drive motor for the compressor, the compressor can be made more compact, resulting in a space-saving cooling drive device, each with an independent 11? The storage room may be provided with a compressor, the power converter, and the signal controller, respectively. In this way each It? Since the temperature of each storage room can be controlled independently, it is easy to control the temperature of the storage room.Also, even if the temperature inside the storage room rises when the door is opened or closed, the compressor capacity of each storage room is varied, so the temperature will not reach the set temperature. Stabilize quickly.

Therefore, the quality preservation of food is improved.

In addition, by controlling the temperature of the vegetable compartment independently,
Is the humidity in the vegetable room from another fl? Since it does not move to the storage room, there is less young frost in the evaporator. Moreover, the ice in the freezer compartment does not carry odors from the vegetable compartment or other storage compartments, making it possible to make ice with a good taste.

Furthermore, in the present invention, the monolithic integrated circuit is housed in a metal case, and the case is attached to the compressor case by direct pin connection or plug-in connection, so that the metal case temperature can be measured as the compressor case temperature. Therefore, there is no need to pull out the compressor side temperature thermistor outside the case, and since the connection wiring between the integrated circuit and the compressor is completely shielded, there is no risk of introducing noise.

This effect is particularly effective in the independent multi-chamber refrigerator. This is because a large number of signal control circuits for a large number of compressors are placed close to each other in the same refrigerator, causing interference between signal wirings.

[Implementation example] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a 4W configuration of a control circuit for driving a refrigerator and a compressor. The compressor power conversion unit 1 includes a power factor improvement reactor 13
, rectifier circuit 6, smoothing capacitor 14, inverter section 5,
The signal control unit 48 is composed of a current detection resistor 55 and a control circuit 7 , and a microcomputer 8° internal temperature detector 49 , a compressor temperature detector 4 , and a microcomputer control circuit 54 . Here, individual circuits will be explained in detail. The rectifier circuit 6 is composed of diodes 15 to 18, and is connected to a commercial power supply 12.
The inverter section 5 has freewheeling diodes 19 to 24.
and transistors 25 to 30 form a voltage bridge connection, and are connected to the drive motor 2 of the compression 813. The control circuit 7 is a power transistor that drives the inverter section 5 and a circuit that protects the elements from overcurrent and temperature, and is connected to the microcomputer 8 by a signal line. The microcomputer control circuit 54 is a circuit for controlling the microcomputer 8.

In the above circuit, the elements that can be monolithically integrated using the dielectric separation method are the rectifier circuit 6, the inverter section 5, the current detection resistor 55. and a control circuit 7. Since the power factor improvement reactor 13 and the smoothing capacitor 14 are energy elements with a large capacity, it is difficult to form them into a monolithic circuit. Also.

Since the rectifier circuit 6 simply rectifies current, the area of the monolithic integrated circuit increases depending on the capacitance, so it may be better not to integrate it. In one embodiment of the present invention, only the power conversion section is made monolithic, but the signal control section, which generally uses the microcomputer 8, can also be made monolithic if its capacity is small.

Here, we will briefly explain the dielectric separation method.

Recently, the development of power ICs has been progressing in which monolithic output elements capable of handling large currents, circuits for controlling the operation of the output elements, and protection function circuits for currents and voltages are integrated. Conventional isolation technology using pn junctions.

As the voltage was increased, a launch-up phenomenon occurred, and reliability could not normally be ensured above 100 µ. Therefore, we used dielectric separation technology to create a good separation between the element Ts.
Withstand voltage of several hundred volts or more, it can be used even with commercial power supply.

FIG. 2 shows a sectional view of the integrated circuit of the dielectric substrate. This is a vertical power element 3 in a polycrystalline silicon 31 in a substrate.
2, a digital circuit 33, and a drive circuit 34 are formed, and the elements are connected with aluminum wiring 36. Dielectric silicon oxide 35 is provided between these circuits and the polycrystalline silicon 31 and between the circuits to ensure breakdown voltage between the elements.

FIG. 3 is a connection diagram of a metal box housing a compressor and a power converter for the compressor, and FIG. 4 is an enlarged view of the connection section.

This metal box 10 houses a power conversion section and a compressor temperature detector 4 as a signal control section. As an external connection line,
A power line 51 connected to the commercial power source 12 and a signal line 52 connected to the microcomputer 8 of the signal control section are output. From this signal line 52, the number of revolutions of the compressor motor 2 is increased when the temperature inside the refrigerator increases and the number of revolutions of the motor 2 is decreased when the temperature inside the refrigerator decreases. A speed command for controlling the rotation speed and a starting command for the electric motor 2 are input. At this time, if the signal control unit 48 has a small capacity, it can be made into a monolithic circuit, so the metal box 1
It is possible to store it within 0.

Generally, the winding 9 of the electric motor 2 in the compressor 3 is electrically connected to a power converter, so it is pulled out by a sealed terminal pin 11 provided at an end of the compressor 3. Therefore, as shown in FIG.
By providing a receptacle terminal 11' that can be plugged in, the power converter can be directly connected.

In addition, conventionally, a detecting element such as a thermistor is pasted to the compressor 3 to detect the temperature, but the compressor 3 has a built-in compressor temperature detector 4 to prevent the temperature of the compressor 3 from rising too much. Since the metal box 10 with good transmission is in direct contact, the metal box 1
0 and the temperature of the compressor 3 are equivalent, and the temperature of the compressor can be detected without running a thermistor lead wire from the compressor.

According to this configuration, since the thermistor is housed in the metal box 10, it is effective to protect the thermistor from radiation noise. However, in the present invention, the power conversion section is
Since the temperature is always equivalent to a3, if the temperature rises to a certain extent to protect the elements inside the metal box 10, it is necessary to protect the system by reducing the rotation speed of the compressor motor 2 and lowering the compressor temperature. Become. Another protection method is to drive a fan motor installed next to the compressor 3 when the compressor temperature rises to a certain extent.
There is also a method of cooling the metal box 10.

The compressor 3 in the present invention is required to be relatively smaller than the conventional type. Therefore, a conventional constant-speed induction motor is not used, and the compressor motor 2 is controlled by an inverter to increase the speed and output.

Figure 5 (,) shows three storage compartments with different temperature ranges thermally insulated, each storage compartment equipped with an evaporator 44 of the refrigeration cycle on the back, and a condenser 53 and a compressor 3 outside the storage compartment. , a structural diagram of a refrigerator is shown in which a metal box 10 containing a power converter 1 and a pressure and compressor temperature detector 4 is plug-in connected to the compressor 3. Incidentally, FIG. 5(b) shows an 11 diagram of the control system. The three independent storage compartments include a freezer compartment 38, a vegetable compartment 42, and a refrigerator compartment 39, and a power converter unit 1 including a condenser 53 and a compressor temperature detector 4 is placed outside each compartment. , the additional chilled compartment 41 and iced compartment 40 are the refrigerated compartment 39
The temperature of the cold air is controlled by a damper 46. Each of the independent storage compartments is equipped with an internal temperature detector 49, and the internal temperature command is transmitted to each power conversion unit via the microcomputer 8 of the common signal control unit 48. Each compressor 3 is controlled at a rotation speed according to the difference between the temperature of each storage chamber and the one-shot temperature. At this time, one signal control unit 48
So each savings'A! The signal controller 48 receives a command from the temperature detector 49 in the i-room and controls the plurality of power converters 1 to drive the compressor 3, but the signal controllers 48 may also be plural and provided in pairs with the power converter 1. It is possible. Note that since the vegetable compartment has a higher set temperature than other storage compartments, a direct cooling plate 45 may be used instead of the evaporator 44. I would like to add that the freezer compartment is 38. It goes without saying that the refrigerator compartment 39 and the vegetable compartment 42 can be separated.

FIG. 6(,) shows a structural diagram of a refrigerator in which independent storage compartments are each equipped with an evaporator 44 and a manifold valve 56 is controlled. FIG. 6(b) shows a control diagram of the system 11.

Equipped with an evaporation zone 44 disposed in each storage room, one condenser 5 3 for each of the plurality of evaporators 44, and a compressor 3,
A manifold valve is provided between each flow path of the evaporator 44 and the compressor 3, and by controlling the manifold valve 56, the temperature of the evaporator 44 is changed and the temperature of each storage chamber is controlled.

The refrigerator, which does not thermally insulate the storage compartment and whose temperature is controlled using a conventional damper 4G, is equipped with a monolithic power converter 1 and a small compressor 3, and controls the rotation speed of the electric motor 2 to control the temperature inside the refrigerator. It is also possible.

FIG. 7(a) shows the structure of a refrigerator that is equipped with a small variable speed compressor 3 and a condenser 53 outside independent storage compartments, and the compressors 3 are switched by a switch, similar to FIG. 5(a). show. FIG. 7(b) shows an 11 diagram of the control system. 1
The power conversion units 1 and the signal control unit 48 provide
The temperature is controlled by switching the compressors 3 provided in the independent freezer compartment 38, vegetable compartment 42, and refrigerator compartment 39, respectively. The temperature detector 49 provided in each storage compartment detects the temperature of each storage compartment and sends a command to the microcomputer 8 of the signal control unit 48, and the microcomputer 8 determines which compressor 3 provided in each storage compartment is to be driven. is selected, and the power converter 1 is driven. At this time, if the compressor motor is a DC motor, the position of the rotor must be detected, so feedback must be given to the microcomputer 8. Therefore, each storage room is equipped with a compressor 3.
cannot be driven at the same time. Therefore, the microcomputer 8 receives the command from the temperature detector 49 of each storage room, and determines which Jt? It is determined whether the temperature of the storage room is significantly different from the set temperature, the compressor to be driven is selected, and the compressor 3 of each storage room is switched using the switch 50 or the like. In this case, since the compressor 3 provided in each storage room is switched and driven, when the compressor 3 stops, the temperature inside the refrigerator increases. Therefore, the temperature control is controlled by the microcomputer 8 so that the temperature is within the designated temperature range.

If the compressor motor is an alternating current machine, the rotor rotates by being guided by the rotating magnetic field of the stator, so feedback to the microcomputer 8 is not necessary. Therefore, the compressors 3 in each storage chamber can be driven simultaneously. However, if the compressor 3 is driven at the same time, the capacity of the power converter increases. Therefore, the drive element needs to have a large capacity. Incidentally, even when the electric motor is an alternating current machine, it is also possible to operate the compressor 3 in each storage chamber by switching over it using the switch 50 or the like.

[Effects of the Invention] According to the present invention, the power conversion section of the compressor drive control circuit and/or the signal control section for the compression fi motor is integrated into an I/C, and the control circuit has a length of 100 mm and a width of 5.0 mm. , height 3
It can be downsized to about 0mm. In addition, a compact compressor with a built-in electric motor whose rotation speed can be controlled and this I/C circuit are connected together in a plug-in type to create a space-saving cooling system and independently control the temperature of each storage compartment. As a result, the quality of food can be improved by suppressing the temperature control range of each storage compartment to ±1°C or less. In addition, the odor from the vegetable compartment is not transferred to the ice in the freezer compartment, making it possible to make ice with a good taste. Regarding frost formation, by providing an independent storage room, moisture in the vegetable compartment does not enter other storage compartments, making it difficult for frost to form, and defrosting can be done in about one-tenth the time of a conventional refrigerator. It is possible.

Furthermore, although refrigerators generally cannot tolerate malfunctions that would stop their operation, with the refrigerator of the present invention, there is no possibility that all storage compartments will become unusable at the same time.

Even if it breaks down, the circuit is connected in a plug-in type, making it extremely convenient for repairs.

[Brief explanation of the drawing]

Fig. 1 is a compressor drive control circuit that is an embodiment of the present invention, Fig. 2 is a cross-sectional view of an integrated circuit of a dielectric isolation substrate used to implement the present invention, and Fig. 3 is a compressor casing and a compressor drive control circuit. Connection diagram with the metal box housing the power converter, Figure 4 is an enlarged view of the connection, and Figure 5 (a) shows the power converter and common power converter located outside the independent storage space. 5(b) is a system control diagram thereof. FIG. 6(a) is a sectional view of a refrigerator equipped with an evaporator in an independent storage chamber and controlled by a manifold valve 56. ) is the system 15 control diagram, No. 7
In Figure (0), the compressor is placed outside of each independent storage unit, and one power converter and one crystal one signal control unit are used.
Cross-sectional view of a refrigerator that switches and controls the compressor, Figure 7 (
Fig. 8(b) shows a system control diagram thereof, Fig. 8(zl) shows a sectional view of a conventional refrigerator, and Fig. 8(b) shows its system control diagram. ■...Power conversion unit 3...Compressor 5...Inverter unit 7...Control circuit 8...Microcomputer 9...Connection line 11...Terminal 12...Commercial power supply 13... - Power factor correction reactors 15-18...Diodes 19-24...Freewheeling diodes 25-30...Transistors 31...Polycrystalline silicon 32...
Power element 33...Digital circuit 34...
Drive circuit 2, variable speed motor 4...temperature detection HH 6...rectifier circuit 10...metal box 11'...terminal 14...smoothing capacitor 35...dielectric 37...heat sink 39 ... Refrigerator room ■ ... Chilled room 43 ... Fan motor 45 ... Direct cooling plate 47 ... Cold air 49 ... Temperature detector 51 ... Power line 53 ... Condenser, 55 ... Current projection resistor 36...Aluminum wiring 38...Freezer compartment 40...Ice greenhouse 42...Vegetable compartment 44...Evaporator 46...Damper 48...Signal control unit 50...Switch switch 52...Signal Line 54...Microcomputer control unit 56/manifold valve Fig. 5 (α) Fig. 5 (b) b

Claims (1)

[Claims] 1. When the temperature inside the refrigerator rises due to a change in the load inside the refrigerator, a signal is generated to increase the rotation speed of the compressor motor connected to the refrigeration cycle, and when the temperature inside the refrigerator decreases. This is a control device consisting of a signal control unit that generates a signal to reduce the rotational speed, and a power conversion unit for a compressor motor that converts the commercial power supply to direct current or directly converts the frequency. 1. A refrigerator comprising: a component of a power converter of the compressor motor that is substantially integrated into a monolithic circuit, and the power converter and the signal controller are formed on a circuit board. 2. The refrigerator according to claim 1, wherein a plurality of storage compartments having different temperature ranges are thermally insulated, each storage compartment is equipped with an evaporator of a refrigeration cycle, and a condenser and a compressor are respectively provided outside of each storage compartment. , the power converter is connected to the compressor, and the internal temperature detector of the storage room and the signal control unit output a rotation speed control signal of the compressor according to the load, and the power converter is This refrigerator is characterized in that the temperature of each storage compartment is controlled independently by transmitting data to the storage compartment and changing the rotation speed of the compressor. 3. The refrigerator according to claim 2, wherein the power conversion section and the signal control section are arranged on a circuit board, housed in a metal box, and connected to the compressor in a plug-in format. . 4. The refrigerator according to claim 2, wherein a condenser and a compressor are provided outside each storage chamber, and the one power conversion section and the one signal control section control the internal temperature detector of each storage chamber. A refrigerator-mounted control method characterized in that a plurality of the compressors are switched and driven by a switch according to the output. 5. A method for controlling a refrigerator according to claim 4, characterized in that a plurality of the compressors are simultaneously driven by one of the power converters. 6. The refrigerator according to claim 3, comprising a plurality of evaporators, one condenser, and a compressor disposed in each of the plurality of storage compartments, and a plurality of cycles between each evaporator and compressor. A refrigerator comprising a valve and controlling the multi-valve according to the output of a temperature detector in each storage compartment. 7. The refrigerator according to claim 3 or 6, wherein the compressor temperature detector is provided in the power conversion section or the signal control section to directly detect the temperature of the compressor.