JP7314166B2 - refrigerator - Google Patents

Description

The present invention relates to refrigerators.

Refrigerators with fixed speed compressors (fixed speed compressor refrigerators) with thermostatic on/off control of the operation of the compressor to maintain the temperature of the storage compartment are known as refrigerators of simple construction. Also, a refrigerator equipped with a variable speed compressor controlled by an inverter (variable speed compressor type refrigerator) is known as a more power-saving refrigerator.

Furthermore, as disclosed in Patent Document 1, a variable-speed compressor type refrigerator is being studied in which inverter control is performed using a thermostat used in a refrigerator equipped with a fixed-speed compressor to reduce costs. In the present technology, the inverter control circuit acquires the temperature information of the storage chamber from the thermostat and controls the variable speed compressor.

U.S. Pat. No. 6,134,901

However, the output of the thermostat is a signal indicating whether the commercial AC power supplied from the outside is on or off. Therefore, in the above-mentioned variable speed compressor type refrigerator, the voltage of the commercial AC power supply from the outside is directly input as a control signal to the inverter control circuit.

In fixed speed compressor refrigerators, the thermostat output is either directly input to the fixed speed compressor motor or used to control a relay on the fixed speed compressor motor AC input. Since these electrical components are highly resistant to surges, there was no particular problem with surges entering the thermostat output from the commercial AC power supply system. However, it has been found that if the output of the thermostat is directly input to the inverter control circuit, such a surge may be applied and cause failure of the inverter control circuit.

An object of one aspect of the present invention is to provide a variable-speed compressor refrigerator that uses a thermostat for temperature detection, in which failure of an inverter control circuit due to surges is suppressed.

In order to solve the above-described problems, a refrigerator according to an aspect of the present invention includes a compressor, an inverter control circuit that controls the compressor, a storage chamber, a thermostat provided in the storage chamber, a supply line for an external power source voltage to the thermostat, and a ground terminal. A surge protection component is connected between the line and the ground terminal.

According to one aspect of the present invention, in a variable speed compressor refrigerator using a thermostat for temperature detection, it is possible to realize a refrigerator in which failure of an inverter control circuit due to surge is suppressed.

1 is a front view of a refrigerator according to Embodiment 1; FIG. 1 is a front view of the refrigerator according to Embodiment 1 with the door opened. FIG. 2 is a bird's-eye view of the refrigerator according to Embodiment 1 from the rear oblique direction. 1 is a schematic circuit diagram of a refrigerator according to Embodiment 1. FIG. 3 is a schematic diagram showing the outer shape of the thermostat of the refrigerator according to Embodiment 1. FIG. 4 is a circuit diagram showing a specific example of a surge absorption circuit of the refrigerator according to Embodiment 1. FIG. 4 is a schematic circuit diagram of a refrigerator according to Embodiment 2. FIG. 1 is a schematic circuit diagram of a fixed-speed compressor type refrigerator that shares a heat insulating box with the refrigerator according to Embodiment 1. FIG.

[Embodiment 1]
An embodiment of the present invention will be described in detail below with reference to FIGS. 1 to 6. FIG.

FIG. 1 is a front view of a refrigerator 10 according to this embodiment. A door 11 covers almost the entire front surface of the refrigerator 10 . FIG. 2 is a front view with the door 11 opened. The interior of the refrigerator 10 is a storage compartment, which is composed of a freezing compartment 13 and a refrigerating compartment 14 at the top. Inside the door 11, a storage pocket 12 is provided. A shelf plate 15 and a tray 16 are provided in the refrigerator compartment 14 to divide the refrigerator compartment 14 appropriately. A dial 141 is arranged beside the freezer compartment 13 . A dial 141 is a dial for adjusting the set temperature of a thermostat 140 installed in a place that cannot be directly seen from the outside. Thus, in refrigerator 10, thermostat 140 is used to set the temperature of the storage compartment. Although not shown, the wall surface of the freezer compartment 13 also serves as an evaporator, and by cooling the evaporator, the entire storage compartment is maintained at a low temperature. The entire storage compartment composed of the freezing compartment 13 and the refrigerating compartment 14 is configured as a heat insulating box filled with a heat insulating material.

FIG. 3 is a bird's-eye view of the refrigerator 10 from the rear oblique direction. A bottom space 17 that opens toward the back is provided at the bottom of the refrigerator 10 . The bottom space 17 is a space in which a compressor or the like can be placed. A power cord 110 for introducing commercial AC power from the outside into the refrigerator 10 is pulled out from the bottom space 17 to the outside. A ground terminal 120 (E) is provided in the chassis portion of the bottom space 17 . Although not shown in FIG. 3, an inverter control circuit INV and a surge absorption circuit SA, which will be described later, are also installed in the bottom space 17 .

FIG. 4 is a circuit diagram showing an outline of the circuit configuration of refrigerator 10. As shown in FIG. A region surrounded by a dotted line in the drawing indicates the range of the bottom space 17 . The circuit portion disposed outside the bottom space 17 in FIG. 4 is the electrical equipment portion disposed within the heat insulating box. Terminals R 1 , R 2 , Et, T 1 , A 2 , and A 1 are provided at locations where wires are led out from the heat insulating box to the bottom space 17 .

The configuration of the electric circuit inside the heat insulating box is as follows.

Terminal R1 is connected to interior light L via door switch SW, and its return is connected to terminal R2. A wiring branched from the terminal R1 is connected to the terminal A1 and one end of the thermostat TM (140). The other end of thermostat TM is connected to terminal T1. A ground terminal provided on the conductive shell 142 of the thermostat TM (140) is connected to the terminal Et. Terminal A2 is connected to terminal R2.

A terminal R1 and a terminal R2 are a terminal pair for supplying an external power supply voltage inside the heat insulating box. Terminals A 1 and A 2 are a service terminal pair for supplying an external power supply voltage to the compressor installed in the bottom space 17 . A terminal T1 is a terminal for taking out a thermostat signal.

FIG. 5 shows the appearance of the thermostat 140. As shown in FIG. Thermostat 140 includes an electrically conductive shell 142 . Thermostat 140 also includes a pair of external terminals 144 and a grounding terminal 143 provided on conductive outer shell 142 . A pair of external terminals 144 are connected to the terminal T1 and the terminal R1 by wiring. Furthermore, the thermostat 140 has a temperature setting dial 141 and a capillary 146 . A capillary 146 is fitted with a temperature sensing tip and is fixed in place in the reservoir. As an example, the temperature sensing part of capillary 146 is fixed to the wall surface of freezer compartment 13 .

The configuration of the circuits in the bottom space 17 is as follows.

A pair of power cords 110 for introducing a power supply voltage from an external commercial power supply are connected to a pair of AC input terminals of the surge absorption circuit SA near the lead-in portion to the housing of the refrigerator 10 . One AC output terminal L of surge absorbing circuit SA is connected to terminal R1, and the other AC output terminal N is connected to terminal R2. A grounding terminal Es of the surge absorbing circuit SA is connected to the grounding terminal E (120). Terminal Et is connected to ground terminal E (120). It is preferable that the ground terminal E is connected to the ground of an external commercial power source.

Terminal A1 and terminal A2 are connected to the AC input terminal pair of the inverter control board INV. A terminal T1 is connected to a temperature signal input terminal of the inverter control circuit INV. A compressor control output (three-wire) of the inverter control circuit INV is input to the electric motor M of the variable speed compressor 130 . Ground terminals of the inverter control circuit INV and the electric motor M are connected to the ground terminal E (120), respectively.

With the above circuit configuration, the interior light L is lit when the door 11 is opened by turning on/off the door switch SW associated with the opening and closing of the door 11 . The thermostat TM becomes conductive when the detected temperature of the wall surface of the freezer compartment 13 rises above the set upper limit temperature, and outputs a conductive signal (external power supply voltage) to the terminal T1. When the temperature of the wall surface of the freezer compartment 13 to be detected falls below the lower limit temperature, which is the set value, the thermostat TM is turned off and does not output the external power supply voltage to the terminal T1. In other words, at this time, the thermostat TM outputs a cutoff signal (no voltage) to the terminal T1. The inverter control circuit INV is activated by an AC input, and performs ignition control of the inverter based on the above signal input from the thermostat TM to the temperature signal input terminal through the terminal T1. Then, the temperature of the storage chamber is adjusted by controlling the operation and rotation speed of the electric motor M of the variable speed compressor. For such a control method, Patent Document 1 and other known techniques can be applied.

FIG. 6 shows a specific example of the surge absorption circuit SA. The surge absorption circuit SA includes an AC input terminal pair, an AC output terminal pair, and a ground terminal Es. In this specific example, the respective lines are directly connected to the AC input terminal pair and the AC output terminal pair. A surge countermeasure component Sn is connected between the AC input terminal pair (between the AC output terminal pair). This is because normal mode noise is removed by the surge countermeasure component Sn. A surge countermeasure component Sc is connected between the AC output terminal L connected to the terminal R1 connected to the thermostat TM and the grounding terminal Es. This is because common mode noise is removed by the surge countermeasure component Sc.

Here, the surge protection component is an electronic component that has a function of allowing a current to flow through the surge protection component (releasing the surge current) when an overvoltage is applied between both terminals. A surge protection component may also be referred to as a surge absorption component or a surge absorption element. As surge countermeasure parts, parts such as varistors, arresters, and surge absorbers can be used.

Further, two capacitors C are connected in series between a pair of AC output terminals on the AC output terminal pair side of the surge countermeasure components Sn and Sc, and the connection point between the capacitors C is connected to the grounding terminal Es. This constitutes a so-called Y capacitor. This is to prevent switching noise generated by the inverter control circuit INV from leaking into the commercial power system.

With the above configuration, the refrigerator 10 according to Embodiment 1 has the following advantages.

Refrigerator 10 is a variable speed compressor type refrigerator including inverter control circuit INV and variable speed compressor 130 . Therefore, lower power consumption is realized compared to a fixed speed compressor type refrigerator.

Furthermore, because of the specific circuit configuration described above, the heat-insulating box, which is the housing portion of the refrigerator 10 , can be shared with the fixed-speed compressor type refrigerator 90 . Next, referring to FIG. 8, this point will be described.

FIG. 8 is a diagram showing an overview of the circuit configuration of a fixed-speed compressor type refrigerator 90 that shares a heat insulating box with the refrigerator 10 according to the first embodiment. In the figure, the partial configuration of the circuit arranged inside the heat insulating box, which is the area outside the bottom space 17 surrounded by the dotted line, is the same as that of the refrigerator 10 of FIG. Terminals R1, R2, Et, T1, A2, and A1 provided at locations where wires are led out from the heat insulating box to the bottom space 17 are also the same as those of the refrigerator 10 of FIG.

The configuration of the circuits in the bottom space 17 is as follows.

A pair of power cords 110 for introducing an external commercial power supply are connected to terminals R1 and R2. In this regard, the surge absorption circuit SA is omitted from the refrigerator 10, which is a variable speed compressor type refrigerator. Terminal Et is connected to ground terminal E (120). It is preferable that the ground terminal E is connected to the ground of an external commercial power supply.

Terminals A1 and A2 are connected to the AC input pair of motor m of fixed speed compressor 930 via relay RL. On/off control of the relay RL is performed by the output from the thermostat TM of the terminal T1. The motor m may be directly driven by the output from the thermostat TM without using the relay RL. In this case, the terminal connected to the terminal A1 of the AC input pair of the motor m in FIG. 8 is connected to the terminal T1. It will be understood that when relay RL is used, in either case of direct input, conduction/disconnection of thermostat TM turns on/off electric motor m to control the temperature of the reservoir. A PTC (Positive Temperature Coefficient) relay for starting the electric motor may be appropriately connected to the input of the electric motor m.

As can be understood by comparing FIG. 4 and FIG. 8, the insulation box body including the internal electric circuit can be made compatible between the refrigerator 10, which is a variable speed compressor refrigerator, and the fixed speed compressor refrigerator 90. It is difficult to ensure compatibility unless the structure of the heat insulating box including the internal electric circuit is standardized. This is because the inside of the wall of the heat insulating box is filled with a heat insulating material, and the wiring cannot be changed after the heat insulating box is formed. In this respect, according to the present invention, the terminals provided at the locations where the wires are drawn out from the heat insulating box to the bottom space 17 are made to coincide with each other. Therefore, the manufacturer can install a compressor and a peripheral circuit of each type in the open bottom space 17 of the prepared heat insulating box body, and connect wiring to each terminal with a connector or the like, so that a variable speed compressor type refrigerator and a fixed speed compressor type refrigerator can be manufactured separately. Therefore, it is not limited to simply using an inexpensive thermostat system as a temperature sensor, but it becomes possible to mass-produce the heat-insulating box body and to manufacture separately according to demand, so that a variable-speed compressor refrigerator can be realized at a lower cost.

In fixed-speed compressor refrigerators, no special surge countermeasures are taken for the output (terminal T1) of the thermostat TM. This is because the relay RL and the motor m are electrical components that are highly resistant to surges, so surges from the commercial AC power supply system to the output of the thermostat TM pose no particular problem. However, in the refrigerator 10 in which the output of the thermostat TM is input to the inverter control circuit INV, such a surge causes the inverter control circuit INV to malfunction. According to the results of various countermeasures studied by the present inventors, the main cause of the surge that enters from the output of the thermostat TM and causes the inverter control circuit INV to malfunction is common mode noise (surge) between the ground and the terminals of the thermostat TM.

In the refrigerator 10, as shown in FIGS. 4 and 6, on the side of the supply line (L line connected to the terminal R1) of the external power supply voltage from the external commercial power supply to the thermostat TM, a surge countermeasure component Sc that connects the line and the ground terminal E is arranged. This effectively prevents a common mode surge introduced from the terminal T1 to the inverter control circuit INV via the thermostat TM.

In addition, the surge countermeasure component Sc is provided on the bottom space 17 side (the external commercial power supply side) of the terminal R1 before the supply line of the external power supply voltage to the thermostat and the supply line of the external power supply voltage to the inverter control circuit branch in the heat insulating box. Thus, surges that can be introduced from terminal A1 to the AC input of inverter control circuit INV via terminal R1 are also prevented at the same time. In this manner, the surge absorption circuit SA prevents surges that can be introduced to the inverter control circuit INV through the AC input terminal pair (compressor service terminals A1 and A2) and the temperature signal input terminal (terminal T1) with a single circuit. Therefore, the inverter control circuit INV can be completely protected at low cost compared to the case where a separate surge absorption circuit is provided.

Further, in Embodiment 1, since the outer shell 142 of the thermostat TM is connected to the ground terminal E, malfunction of the thermostat TM due to external noise is prevented. Therefore, by connecting the surge countermeasure component Sc between the line connected to the thermostat TM (the line of the terminal R1) and the ground, the common mode noise between the terminal of the thermostat TM and the ground can be removed. Therefore, especially when the thermostat TM is cut off, that is, when the terminal T1 is in an open state, surge noise from the ground terminal E can be prevented from entering the temperature signal input terminal of the inverter control circuit INV and causing a malfunction or failure of the inverter control circuit INV.

Furthermore, in the refrigerator 10, the surge absorption circuit SA is provided in the vicinity of the introduction portion of the power cord 110 into the refrigerator housing. Therefore, introduction of surge into refrigerator 10 itself is prevented. For example, if the surge absorption circuit SA is provided immediately before the inverter control circuit INV, the surge itself that may be introduced into the inverter control circuit INV can be prevented, but the surge will pass through the wiring inside the refrigerator. This can cause inductive noise within the refrigerator, which can cause problems when other electronic devices are located within the refrigerator. However, with the refrigerator 10, such a fear is also prevented. Here, the vicinity of the introduction portion to the refrigerator housing refers to the area immediately inside the portion where the power cord 110 is pulled out from the refrigerator housing in FIG. Also, in the circuit diagram of FIG. 4, it means the immediate vicinity from the terminal to which the power cord 110 is fixed. Alternatively, in the circuit diagram of FIG. 4, it means that the terminal to which the power cord 110 is fixed is directly connected to the surge absorption board SA without going through another circuit board or wiring inside the heat insulation box.

Also, in the surge absorption circuit SA, the Y capacitor for preventing the switching noise generated by the inverter control board INV from leaking to the external power supply has a limited withstand voltage, and may be damaged by a surge from the external commercial power supply. However, in the refrigerator 10, in the surge absorption circuit SA, the surge countermeasure component Sc and the surge countermeasure component Sn are provided on the upstream side (external commercial power supply side) of the Y capacitor, so that the surge that damages the Y capacitor is effectively removed.

[Embodiment 2]
Other embodiments of the invention are described below. For convenience of description, members having the same functions as those of the members described in the above embodiments are denoted by the same reference numerals, and description thereof will not be repeated. The same applies to the following embodiments.

A refrigerator 20 according to Embodiment 2 has a structure similar to that of the refrigerator 10 shown in FIGS. However, the circuit configuration in the bottom space 17 is different from that of the refrigerator 10 . FIG. 7 is a circuit diagram showing an outline of an electric circuit of refrigerator 20. As shown in FIG. A region surrounded by a dotted line in the drawing indicates the range of the bottom space 17 .

Terminals R1, R2, Et, T1, A2, and A1 provided at locations where wires are led out from the heat insulating box to the bottom space 17 are the same as those of the refrigerator 10 . The configuration of the circuits in the bottom space 17 is as follows.

Refrigerator 20 is provided with circuit board 150 in the vicinity of variable speed compressor 130, on which inverter control circuit INV and surge absorption circuit SA are configured.

Wiring connected to a pair of power cords 110 for introducing an external commercial power supply is connected to a pair of AC input terminals of the surge absorption circuit SA. The AC output terminal pair of the surge absorption circuit SA is input to the AC input terminal pair of the inverter control circuit INV within the circuit board 150 . One AC output terminal L of the surge absorption circuit SA is branched and connected to the terminal R1, and the other AC output terminal N is branched and connected to the terminal R2. The ground terminal of the inverter control circuit INV and the ground terminal Es of the surge absorption circuit SA are connected to the ground terminal E (120). The grounding terminal of the inverter control circuit INV and the grounding terminal Es of the surge absorption circuit SA may be connected within the circuit board 150 to form a common terminal. Further, it is preferable that the ground terminal E is connected to the ground of an external commercial power source. A compressor control output (three-wire) of the inverter control circuit INV is input to the electric motor M of the variable speed compressor 130 . The terminal Et and the grounding terminal of the electric motor M are connected to the grounding terminal E (120).

Since the AC input to the inverter control circuit INV is performed from the surge absorption circuit SA within the circuit board 150, wiring is not connected to the bottom space 17 side of the terminals A1 and A2. However, refrigerator 20 also has the same circuit configuration electrically as refrigerator 10, except that the position of surge absorption circuit SA is different. Therefore, in the second embodiment as well, the same effects as in the first embodiment can be obtained except for the difference in the effects due to the difference in the physical position where the surge absorption circuit SA is installed.

In refrigerator 20 , surge absorption circuit SA and inverter control circuit INV can be formed on the same circuit board 150 . Alternatively, they can be formed in the same housing even if they are on separate circuit boards. Therefore, compared with the case where the circuit board and the housing are separately formed as in the first embodiment, the cost can be further reduced.

Furthermore, in the second embodiment, the surge absorption circuit SA and the inverter control circuit INV can be packaged together with the variable speed compressor 130, such as by being attached to the variable speed compressor 130. FIG. As a result, a variable speed compressor type refrigerator can be easily made simply by replacing a conventional fixed speed compressor with a variable speed compressor and performing wiring processing, and a variable speed compressor type refrigerator can be realized at a lower cost and with fewer processes.

[Additional notes]
In each embodiment above, the case where the surge absorption circuit SA is a specific example has been described. However, the specific configuration of the surge absorbing circuit SA is not limited to the above. For example, in the circuit diagram of FIG. 6, it is possible to omit the surge countermeasure component Sn between the AC input terminal pair, the Y capacitor, or both. Alternatively, in the circuit diagram of FIG. 6, it is also possible to add a grounded surge protection component to the side of the AC input terminal where the grounded surge protection component Sc is not provided. Also, in order to more effectively prevent leakage of switching noise from the inverter control circuit INV, an X capacitor may be provided in the circuit. Also, the AC input terminal pair and the AC output terminal pair are directly connected with their respective lines, but this is not limiting, and a filter element such as a coil may be interposed between the AC input terminal pair and the AC output terminal pair.

〔summary〕
A refrigerator according to aspect 1 of the present invention includes a compressor, an inverter control circuit for controlling the compressor, a storage compartment (freezer compartment 13 and refrigerator compartment 14), a thermostat provided in the storage compartment, a supply line for an external power supply voltage to the thermostat, and a ground terminal. A surge countermeasure component is connected between the supply line of the external power supply voltage and the ground terminal.

According to the above configuration, in a variable speed compressor type refrigerator using a thermostat for temperature detection, it is possible to realize a refrigerator in which failure of the inverter control circuit due to surge is suppressed.

In the refrigerator according to aspect 2 of the present invention, in the above-described aspect 1, the refrigerator may include an external power supply voltage supply line to the inverter control circuit, and the surge countermeasure component may be connected upstream of a branch point between the external power supply voltage supply line to the thermostat and the external power supply voltage supply line to the inverter control circuit.

According to the above configuration, not only the surge entering from the supply line of the power supply voltage to the thermostat, but also the surge entering from the supply line of the power supply voltage to the inverter control circuit can be suppressed by the surge countermeasure component.

A refrigerator according to aspect 3 of the present invention, in aspect 1 or 2, may include a power cord for introducing the external power supply voltage, and may include a configuration in which the surge countermeasure component is arranged near an introduction portion of the power cord into the refrigerator housing.

According to the above configuration, it is possible to suppress not only the surge that enters the inverter control circuit from the supply line of the power supply voltage to the thermostat, but also the surge that enters the refrigerator.

In the refrigerator according to aspect 4 of the present invention, in the above aspects 1 to 3, the surge countermeasure component may be arranged on the same substrate or in the same housing as the inverter control circuit.

According to the above configuration, the surge countermeasure component and the inverter control circuit do not have to be handled as separate components, and a variable speed compressor refrigerator can be realized at lower cost and with fewer steps.

In the refrigerator according to aspect 5 of the present invention, in any one of aspects 1 to 4, the thermostat may include a conductive outer shell, and the wiring connected to the ground terminal may be connected to the outer shell.

According to the above configuration, it is possible to effectively suppress the surge entering the inverter control circuit from the supply line of the power supply voltage to the thermostat.

In the refrigerator according to aspect 6 of the present invention, in any one of aspects 1 to 5, the surge countermeasure component may include a varistor, a surge absorber, or an arrester.

According to the above configuration, the surge countermeasure component can be specifically configured.

The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments are also included in the technical scope of the present invention. Furthermore, new technical features can be formed by combining the technical means disclosed in each embodiment.

Reference Signs List 10, 20 refrigerator 11 door 12 storage pocket 13 freezer compartment 14 refrigerator compartment 15 shelf board 16 tray 17 bottom space 110 power cord 120 ground terminal (E)
130 variable speed compressor 140 thermostat (TM)
141 Dial 142 Outer shell 143 Ground terminal 144 External terminal 146 Capillary 150 Circuit board INV Inverter control circuit SA Surge absorption circuit Sc, Sn Surge countermeasure parts

Claims (6)

A compressor, an inverter control circuit that controls the compressor, a storage chamber, a thermostat provided in the storage chamber, an external power supply voltage supply line to the thermostat, and a ground terminal,
the thermostat outputs the external power supply voltage to the inverter control circuit in a conductive state and does not output the external power supply voltage to the inverter control circuit in a disconnected state;
A refrigerator, wherein a surge countermeasure component is connected between a supply line of an external power supply voltage to said thermostat and said earth terminal. A supply line for an external power supply voltage to the inverter control circuit,
2. The refrigerator according to claim 1, wherein the surge countermeasure component is connected upstream of a branch point between a supply line of the external power supply voltage to the thermostat and a supply line of the external power supply voltage to the inverter control circuit. A power cord for introducing the external power supply voltage,
3. The refrigerator according to claim 1, wherein said surge countermeasure component is arranged in the vicinity of an introduction portion of said power cord into said refrigerator housing. 4. The refrigerator according to any one of claims 1 to 3, wherein said surge countermeasure component is arranged on the same board or in the same housing as said inverter control circuit. 5. The refrigerator according to any one of claims 1 to 4, wherein said thermostat has an electrically conductive shell, and a wire connected to said ground terminal is connected to said shell. 6. The refrigerator according to any one of claims 1 to 5, wherein the surge countermeasure component includes any one of a varistor, a surge absorber, and an arrester.

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