Refrigerator

Abstract

To reduce consumption power of an inverter control circuit in a refrigerator in which an external source voltage is input from a thermostat to an inverter control circuit.SOLUTION: A refrigerator includes: a housing with a storage room therein; a thermostat including a first external terminal and a second external terminal to which an external source voltage is input, and assuming a conducting state or a cut-off state according to a temperature of the storage room; a compressor; and an inverter control circuit including an AC voltage input terminal electrically connected to the second external terminal, wherein the inverter control circuit determines a rotational frequency in a current operation of the compressor when a control circuit is driven by an AC voltage input to the AC voltage input terminal and is input into the AC voltage input terminal, operates the compressor at said rotational frequency while the external source voltage is being input to the AC voltage input terminal, and stops the control circuit and the compressor while the external source voltage is not being input to the AC voltage input terminal.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a refrigerator.

Background Art

[0002] Patent Document 1 discloses a refrigerator. In the refrigerator, when the temperature of the wall surface of the freezer compartment rises above the upper limit temperature, the thermostat outputs an external power supply voltage to terminal T, and when the temperature drops below the lower limit temperature, the thermostat does not output an external power supply voltage to terminal T. The inverter control circuit performs arc ignition control of the inverter based on the external power supply voltage input to the temperature signal input terminal through terminal T, and controls the operation and rotation speed of the motor of the variable speed compressor to adjust the temperature of the storage compartment (paragraph 0022).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the refrigerator disclosed in Patent Document 1, even when the temperature of the wall surface of the freezer compartment drops below the lower limit temperature, the inverter control circuit remains energized. For this reason, the power consumption of the inverter control circuit increases.

[0005] The present disclosure has been made in view of this problem. One aspect of the present disclosure aims to reduce the power consumption of the inverter control circuit in a refrigerator in which an external power supply voltage is input from a thermostat to the inverter control circuit, for example.

Means for Solving the Problems

[0006] A refrigerator according to an aspect of the present disclosure includes a housing in which a storage chamber is formed, a first external terminal to which an external power supply voltage is input, and a second external terminal. A thermostat configured to be in a conduction state in which the second external terminal conducts with the first external terminal or an off state in which the second external terminal does not conduct with the first external terminal according to the temperature of the storage chamber, a compressor, and an AC voltage input terminal electrically connected to the second external terminal. A control circuit is driven by an AC voltage input to the AC voltage input terminal, determines the rotation speed of the compressor during the current operation when the AC voltage is input to the AC voltage input terminal, and operates the compressor at the rotation speed while the external power supply voltage is input to the AC voltage input terminal, and an inverter control circuit that stops the control circuit and the compressor while the external power supply voltage is not input to the AC voltage input terminal. It comprises.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

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Figure 16

[0008] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same or equivalent elements are denoted by the same reference numerals, and redundant descriptions are omitted.

[0009] 1 First Embodiment 1.1 Structure of Refrigerator FIG. 1 is a front view schematically showing a state in which the door of the refrigerator according to the first embodiment is closed. FIG. 2 is a front view schematically showing a state in which the door of the refrigerator according to the first embodiment is open.

[0010] Refrigerators include a fixed-speed compressor type refrigerator that controls the on / off of a fixed-speed compressor with a fixed rotation speed according to the output of a thermostat, and a variable-speed compressor type refrigerator that controls the on / off and rotation speed of a variable-speed compressor with a variable rotation speed according to the output of an inverter. The fixed-speed compressor type refrigerator has a simple structure but does not have high power-saving performance. On the other hand, the variable-speed compressor type refrigerator has a complex structure but has high power-saving performance. The refrigerator 1 of the first embodiment illustrated in FIGS. 1 to 4 is a variable-speed compressor type refrigerator in which the fixed-speed compressor provided in the fixed-speed compressor type refrigerator is replaced with a variable-speed compressor. Thereby, most of the refrigerator 1 can be composed of components common to the components constituting the fixed-speed compressor type refrigerator. Thereby, the development cost of the refrigerator 1 can be reduced.

[0011] As illustrated in FIGS. 1 and 2, the refrigerator 1 includes a housing 11, a shelf 12, a tray 13, a dial 14, and a door 15.

[0012] The housing 11 has a box shape. A storage chamber 11A and an opening 11B are formed in the housing 11. The storage chamber 11A is formed inside the housing 11. The opening 11B is formed on the front surface of the housing 11. Each wall surface of the housing 11 is filled with a heat insulating material. Thereby, the housing 11 prevents heat exchange between the storage chamber 11A formed inside the housing 11 and the outside of the housing 11. The storage chamber 11A is exposed to the outside of the housing 11 through the opening 11B when the door 15 is opened. The storage chamber 11A is sealed by the housing 11 and the door 15 when the door 15 is closed.

[0013] The storage chamber 11A includes a freezer compartment 11D and a refrigerating compartment 11E. The freezer compartment 11D is disposed vertically above the refrigerating compartment 11E. The refrigerating compartment 11E communicates with the freezer compartment 11D.

[0014] The inner wall surrounding the freezer compartment 11D also serves as the evaporator that constitutes the refrigeration cycle. The evaporator evaporates the refrigerant that constitutes the refrigeration cycle and extracts heat from the air present inside the freezer compartment 11D. As a result, the evaporator cools the freezer compartment 11D and the refrigerator compartment 11E communicating with the freezer compartment 11D.

[0015] The shelf 12 is housed in the refrigerator compartment 11E. The shelf 12 has a plate-like shape. The shelf 12 separates the space above the shelf 12 in the vertical direction from the space below the shelf 12 in the vertical direction. An object to be stored is placed on the shelf 12.

[0016] The tray 13 is housed in the refrigerator compartment 11E. The tray 13 has a box-like shape. The tray 13 separates the space inside the tray 13 from the space outside the tray 13. An object to be stored is stored in the tray 13.

[0017] The dial 14 accepts an operation for adjusting the set temperature. The dial 14 may be replaced with an operation member other than a dial. The dial 14 is disposed on the side of the freezer compartment 11D.

[0018] The door 15 is coupled to the housing 11. The door 15 is openable and movable between a position where it does not block the opening 11B and a position where it blocks the opening 11B. When the door 15 is opened, it is disposed at a position where it does not block the opening 11B. When the door 15 is closed, it is disposed at a position where it blocks the opening 11B.

[0019] A storage pocket 15A is formed in the door 15. The storage pocket 15A is formed on the inner surface of the door 15. An object to be stored is stored in the storage pocket 15A.

[0020] FIG. 3 is a perspective view schematically showing the refrigerator of the first embodiment.

[0021] As shown in FIG. 3, the refrigerator 1 includes a housing 11, a chassis 16, an earth terminal 17, a compressor 18, and a power cord 19.

[0022] The chassis 16 has a skeletal shape. A bottom space 16A is formed in the chassis 16. The bottom space 16A is disposed outside the housing 11 and is exposed on the back surface of the refrigerator 1. The chassis 16 supports the ground terminal 17 and the compressor 18.

[0023] The ground potential is applied to the ground terminal 17. The ground terminal 17 is preferably grounded. The ground terminal 17 is disposed in the bottom space 16A.

[0024] The compressor 18 compresses the refrigerant that constitutes the refrigeration cycle. The compressor 18 is disposed in the bottom space 16A. The compressor 18 is a variable speed compressor. Therefore, the rotational speed of the compressor 18 is variable.

[0025] The power cord 19 is detachable from the outlet. When the power cord 19 is attached to the outlet, the power cord 19 conducts the external power supply voltage from the outlet. The conducted external power supply voltage is supplied from a commercial power supply.

[0026] 1.2 Circuit of the Refrigerator FIG. 4 is a circuit diagram of the refrigerator according to the first embodiment.

[0027] As shown in FIG. 4, the refrigerator 1 includes a ground terminal 17, a compressor 18, a power cord 19, a first terminal pair 20, a surge absorption circuit 21, a second terminal pair 22, a thermostat 23, a third terminal pair 24, a terminal 25, a detection unit 26, an inverter control circuit 27, a door switch 28, and an indoor lamp 29. The first terminal pair 20 includes a first terminal 20X and a second terminal 20Y. The second terminal pair 22 includes a first terminal 22X and a second terminal 22Y. The third terminal pair 24 includes a first terminal 24X and a second terminal 24Y.

[0028] The ground terminal 17, the compressor 18, the first terminal pair 20, the surge absorption circuit 21, the second terminal pair 22, the third terminal pair 24, the terminal 25, and the inverter control circuit 27 are arranged in the bottom space 16A. The first terminal pair 20, the second terminal pair 22, the third terminal pair 24, and the terminal 25 are arranged at positions where wiring is drawn out from the housing 11. The thermostat 23, the door switch 28, and the indoor lamp 29 are arranged inside the housing 11. The detection unit 26 is arranged outside the housing 11.

[0029] As shown in FIG. 4, the power cord 19 includes a plug 40, a first cord 41, and a second cord 42. The plug 40 includes a first plug blade 51 and a second plug blade 52.

[0030] The first plug blade 51 and the second plug blade 52 can be inserted into and removed from the first insertion port and the second insertion port of the outlet, respectively. When the first plug blade 51 and the second plug blade 52 are inserted into the first insertion port and the second insertion port, respectively, they are electrically connected to the first insertion port and the second insertion port, respectively.

[0031] One end of the first cord 41 is coupled to the first plug blade 51 and is electrically connected to the first plug blade 51. One end of the second cord 42 is coupled to the second plug blade 52 and is electrically connected to the second plug blade 52. Thereby, the power cord 19 conducts the external power supply voltage from the first plug blade 51 and the second plug blade 52 to the other end of the first cord 41 and the other end of the second cord 42.

[0032] The first terminal 20X is coupled to the other end of the first cord 41 and is electrically connected to the other end of the first cord 41. The second terminal 20Y is coupled to the other end of the second cord 42 and is electrically connected to the other end of the second cord 42. Thereby, the power cord 19 conducts the external power supply voltage from the first insertion port and the second insertion port to the first terminal 20X and the second terminal 20Y.

[0033] As shown in FIG. 4, the surge absorption circuit 21 includes an input terminal pair 61, an output terminal pair 62, and a ground terminal 63. The input terminal pair 61 includes a first input terminal 61X and a second input terminal 61Y. The output terminal pair 62 includes a first output terminal 62X and a second output terminal 62Y.

[0034] The surge absorption circuit 21 electrically connects the first input terminal 61X and the second input terminal 61Y to the first output terminal 62X and the second output terminal 62Y, respectively. Thereby, the surge absorption circuit 21 outputs the external power supply voltage input to the first input terminal 61X and the second input terminal 61Y from the first output terminal 62X and the second output terminal 62Y.

[0035] The surge absorption circuit 21 includes surge countermeasure components. The surge countermeasure components conduct current when an overvoltage is applied. The surge countermeasure components are also called surge absorption components, surge absorption elements, etc. The surge countermeasure components are varistors, arresters, surge absorbers, etc. The surge countermeasure components are inserted between the first input terminal 61X and the second input terminal 61Y. Thereby, the surge absorption circuit 21 absorbs the surge input to the first input terminal 61X and the second input terminal 61Y and suppresses the output of the surge from the first output terminal 62X and the second output terminal 62Y.

[0036] The first input terminal 61X and the second input terminal 61Y are electrically connected to the first terminal 20X and the second terminal 20Y respectively. The first terminal 22X and the second terminal 22Y are electrically connected to the first output terminal 62X and the second output terminal 62Y respectively. Thereby, the surge absorption circuit 21 causes the external power supply voltage led by the power cord 19 to be output from the first terminal 22X and the second terminal 22Y. Also, the surge absorption circuit 21 suppresses the output of the surge led by the power cord 19 from the first terminal 22X and the second terminal 22Y. Thereby, it is possible to suppress the circuit subsequent to the first terminal 22X and the second terminal 22Y from failing due to a surge. In particular, it is possible to suppress the inverter control circuit 27 from failing due to a surge. The ground terminal 63 is electrically connected to the ground terminal 17. Thereby, the surge absorption circuit 21 prevents the first terminal 22X and the second terminal 22Y from exceeding a determined upper limit voltage with respect to the ground potential to which the ground terminal 17 is connected.

[0037] The surge absorption circuit 21 may be omitted. When the surge absorption circuit 21 is omitted, the first terminal 22X and the second terminal 22Y are coupled to the first terminal 20X and the second terminal 20Y respectively, and are electrically coupled to the other end of the first cord 41 and the other end of the second cord 42 respectively. In this case, the first terminal pair 20 and the second terminal pair 22 can be omitted.

[0038] As shown in FIG. 4, the thermostat 23 includes a first external terminal 71, a second external terminal 72, and a ground terminal 73.

[0039] The thermostat 23 is arranged in the storage chamber 11A. The thermostat 23 assumes a conducting state in which the second external terminal 72 is electrically connected to the first external terminal 71 or a blocking state in which the second external terminal 72 is not electrically connected to the first external terminal 71 according to the temperature of the storage chamber 11A. The thermostat 23 includes the above-described dial 14. When the temperature of the storage chamber 11A becomes higher than the upper limit temperature of the set temperature adjusted by the dial 14, the thermostat 23 assumes a conducting state, and when the temperature of the storage chamber 11A becomes lower than the lower limit temperature of the set temperature, the thermostat 23 assumes a blocking state.

[0040] The first external terminal 71 is electrically connected to the first terminal 22X. Thereby, an external power supply voltage is input to the first external terminal 71. The ground terminal 73 is electrically connected to the terminal 25. The terminal 25 is electrically connected to the ground terminal 17. Thereby, the ground terminal 73 is electrically connected to the ground terminal 17 via the terminal 25.

[0041] The first terminal 24X is electrically connected to the second external terminal 72. The second terminal 24Y is electrically connected to the second terminal 22Y.

[0042] The detection unit 26 detects the temperature of the outside air of the refrigerator 1 and outputs a signal indicating the detected temperature. The detection unit 26 is a temperature sensor or the like.

[0043] As illustrated in FIG. 4, the inverter control circuit 27 includes an input terminal pair 81, an output terminal group 82, and a ground terminal 83. The input terminal pair 81 includes a first input terminal 81X and a second input terminal 81Y. The output terminal group 82 includes a first output terminal 82X, a second output terminal 82Y, and a third output terminal 82Z.

[0044] While an external power supply voltage is input to the first input terminal 81X and the second input terminal 81Y, the inverter control circuit 27 generates a driving voltage from the input external power supply voltage and outputs the generated driving voltage from the first output terminal 82X, the second output terminal 82Y, and the third output terminal 82Z. While no external power supply voltage is input to the first input terminal 81X and the second input terminal 81Y, the inverter control circuit 27 does not output a driving voltage from the first output terminal 82X, the second output terminal 82Y, and the third output terminal 82Z.

[0045] The first input terminal 81X is electrically connected to the first terminal 24X. Thereby, the first input terminal 81X is electrically connected to the second external terminal 72 via the first terminal 24X and is electrically connected to the first terminal 22X via the thermostat 23. The second input terminal 81Y is electrically connected to the second terminal 24Y. Thereby, the second input terminal 81Y is electrically connected to the second terminal 22Y via the second terminal 24Y. Due to these, while the thermostat 23 is in a conductive state, an external power supply voltage is input to the first input terminal 81X and the second input terminal 81Y. On the other hand, while the thermostat 23 is in an open state, no external power supply voltage is input to the first input terminal 81X and the second input terminal 81Y. The ground terminal 83 is electrically connected to the ground terminal 17. Note that the second terminal 24Y may be omitted. In this case, the second input terminal 81Y is electrically connected to the second terminal 22Y within the bottom space 16A.

[0046] The inverter control circuit 27 is electrically connected to the detection unit 26. Thereby, the inverter control circuit 27 can receive a signal indicating the temperature of the outside air of the refrigerator 1. The inverter control circuit 27 can control the driving voltage based on the temperature indicated by the received signal.

[0047] As shown in FIG. 4, the compressor 18 includes an input terminal group 91 and a ground terminal 92. The input terminal group 91 includes a first input terminal 91X, a second input terminal 91Y, and a third input terminal 91Z.

[0048] The compressor 18 operates while a driving voltage is input to the first input terminal 91X, the second input terminal 91Y, and the third input terminal 91Z. While operating, the compressor 18 rotates at a rotational speed corresponding to the input driving voltage waveform to compress the refrigerant. On the other hand, the compressor 18 stops when no driving voltage is input to the first input terminal 91X, the second input terminal 91Y, and the third input terminal 91Z. While stopped, the compressor 18 does not rotate and does not compress the refrigerant.

[0049] The first input terminal 91X, the second input terminal 91Y, and the third input terminal 91Z are electrically connected to the first output terminal 82X, the second output terminal 82Y, and the third output terminal 82Z, respectively. Thereby, the compressor 18 operates while a driving voltage is output from the first output terminal 82X, the second output terminal 82Y, and the third output terminal 82Z. On the other hand, the compressor 18 stops while no driving voltage is output from the first output terminal 82X, the second output terminal 82Y, and the third output terminal 82Z. The ground terminal 92 is electrically connected to the ground terminal 17.

[0050] As a result, while the temperature of the storage chamber 11A is higher than the set upper limit temperature and then becomes equal to or lower than the set lower limit temperature (while the thermostat 23 is in the conductive state and an external power supply voltage is input to the first input terminal 81X and the second input terminal 81Y), the inverter control circuit 27 operates the compressor 18. The inverter control circuit 27 stops the compressor 18 while the temperature of the storage chamber 11A is equal to or lower than the set lower limit temperature and then becomes higher than the set upper limit temperature (while the thermostat 23 is in the cut-off state and an external power supply voltage is not input to the first input terminal 81X and the second input terminal 81Y). While the compressor 18 is stopped, no external power supply voltage is input to the inverter control circuit 27. Thereby, the power consumption of the inverter control circuit 27 can be reduced. For example, the power consumption of the inverter control circuit 27 can be reduced by about 35%. Also, the probability of failure of the inverter control circuit 27 due to a surge can be lowered. The reason why the probability of failure of the inverter control circuit 27 due to a surge can be lowered when no external power supply voltage is input to the inverter control circuit 27 is that the probability of failure of the inverter control circuit 27 due to a surge when the inverter control circuit 27 is energized is higher than the probability of failure of the inverter control circuit 27 due to a surge when the inverter control circuit 27 is not energized. Thereby, it becomes possible to reduce the absorption capacity of the surge absorption circuit 21 or omit the surge absorption circuit 21.

[0051] As shown in FIG. 4, the door switch 28 includes a first terminal 111 and a second terminal 112.

[0052] The door switch 28 assumes a conductive state in which the second terminal 112 is conductive to the first terminal 111 or a cut-off state in which the second terminal 112 is not conductive to the first terminal 111 according to the position where the door 15 is disposed. The door switch 28 is in the conductive state while the door 15 is disposed at a position where it does not block the opening 11B. On the other hand, the door switch 28 is in the cut-off state while the door 15 is disposed at a position where it blocks the opening 11B.

[0053] The first terminal 111 is electrically connected to the first terminal 22X.

[0054] As shown in FIG. 4, the interior light 29 includes a first terminal 121 and a second terminal 122.

[0055] The interior light 29 is turned off while no external power supply voltage is input to the first terminal 121 and the second terminal 122. The interior light 29 is turned on while an external power supply voltage is input to the first terminal 121 and the second terminal 122.

[0056] The first terminal 121 is electrically connected to the second terminal 112. Thereby, the first terminal 121 is electrically connected to the first terminal 22X via the door switch 28. The second terminal 122 is electrically connected to the second terminal 22Y. Thereby, while the door switch 28 is in a conductive state, an external power supply voltage is input to the first terminal 121 and the second terminal 122. While the door switch 28 is in an open state, no external power supply voltage is input to the first terminal 121 and the second terminal 122.

[0057] Accordingly, the interior light 29 is arranged at a position where the door 15 does not block the opening 11B and is turned on while an external power supply voltage is input to the first terminal 121 and the second terminal 122. The interior light 29 is arranged at a position where the door 15 blocks the opening 11B and is turned off while no external power supply voltage is input to the first terminal 121 and the second terminal 122.

[0058] In the above description, the fact that the first element is electrically connected to the second element includes the fact that the first element is directly connected to the second element and the fact that the first element is connected to the second element via a wiring.

[0059] 1.3 Thermostat FIG. 5 is a perspective view schematically showing a thermostat provided in the refrigerator of the first embodiment.

[0060] As shown in FIG. 5, the thermostat 23 includes a dial 14, a first external terminal 71, a second external terminal 72, a capillary 74, and an outer case 75.

[0061] The dial 14, the first external terminal 71, and the second external terminal 72 are disposed outside the outer shell 75.

[0062] The capillary 74 has a linear shape and is flexible. One end of the capillary 74 is disposed inside the outer shell 75. The other end of the capillary 74 is provided with a temperature detection unit 131. The temperature detection unit 131 is fixed inside the storage chamber 11A. Thereby, the temperature detection unit 131 can detect the temperature of the storage chamber 11A. The temperature detection unit 131 is fixed, for example, on the wall surface surrounding the freezer compartment 11D.

[0063] The outer shell 75 is made of a conductive material. The outer shell 75 is provided with an earth terminal 73. Thereby, the outer shell 75 is grounded via the terminal 25 and the earth terminal 17. Thereby, it is possible to suppress noise from entering from the outside of the outer shell 75 into the inside of the outer shell 75.

[0064] 1.4 Inverter control circuit FIG. 6 is a block diagram of an inverter control circuit provided in the refrigerator according to the first embodiment.

[0065] As shown in FIG. 6, the inverter control circuit 27 includes a drive circuit 141, a control unit 142, and a storage unit 143.

[0066] The drive circuit 141 generates a drive voltage from the external power supply voltage input to the first input terminal 81X and the second input terminal 81Y, and outputs the generated drive voltage from the first output terminal 82X, the second output terminal 82Y, and the third output terminal 82Z according to a control signal from the control unit 142. The drive circuit 141 includes a converter, an inverter, and an accessory circuit.

[0067] The control unit 142 controls the drive voltage output by controlling the drive circuit 141. Thereby, the control unit 142 controls the rotational speed of the compressor 18. The control unit 142 writes information necessary to control the rotational speed of the compressor 18 during the next and subsequent operations into the storage unit 143, and reads out information necessary to control the rotational speed of the compressor 18 during the current operation from the storage unit 143. The control unit 142 is constituted by a processor. The processor reads out a program stored in the storage unit 143, executes the read program, and performs processing necessary to control the rotational speed of the compressor 18. A dedicated electronic circuit may perform all or part of the processing necessary to control the rotational speed of the compressor 18.

[0068] The storage unit 143 stores information necessary to control the rotational speed of the compressor 18 and a program executed by the processor. The storage unit 143 is constituted by a memory, a storage, etc.

[0069] The drive circuit 141, the control unit 142, and the storage unit 143 operate by an external power supply voltage input to the first input terminal 81X and the second input terminal 81Y. Further, the control unit 142 and the storage unit 143 can operate for a short period (about several seconds) immediately after a change occurs from a state where an external power supply voltage is input to the first input terminal 81X and the second input terminal 81Y to a state where no external power supply voltage is input to the first input terminal 81X and the second input terminal 81Y by a backup function.

[0070] 1.5 Information Used to Control the Rotational Speed of the Compressor FIG. 7 is a diagram showing information used to control the rotational speed of the compressor provided in the refrigerator according to the first embodiment.

[0071] As shown in FIG. 7, the inverter control circuit 27 uses the operation time 152 during the past operation of the compressor 18 to control the rotation speed 151 during the current operation of the compressor 18. When the inverter control circuit 27 uses the operation time 152 during the past operation, it controls the rotation speed 151 during the current operation based on the operation time 152 during the past operation. For example, the inverter control circuit 27 controls the rotation speed 151 during the current operation based on the operation time 162 during the previous operation of the compressor 18. The inverter control circuit 27 increases the rotation speed 151 during the current operation as the operation time 152 during the past operation becomes longer. Thereby, when the cooling capacity of the refrigeration cycle was insufficient during the past operation of the compressor 18 and the operation time 152 during the past operation became long, the cooling capacity of the refrigeration cycle can be increased during the current operation of the compressor 18. Thereby, the operation time during the current operation of the compressor 18 can be shortened.

[0072] The inverter control circuit 27 increases the rotational speed 151 during the current operation of the compressor 18 as the operation time 152 during the previous operation becomes longer than the preset steady operation time, and decreases the rotational speed 151 during the current operation as the operation time 152 during the previous operation becomes shorter than the steady operation time. By repeating this, the rotational speed of the compressor 18 can be converged to the steady rotational speed, the operation time of the compressor 18 can be brought closer to the steady operation time, and the operation rate of the compressor 18 can be brought closer to the steady operation rate. The steady rotational speed is, for example, 1400 to 2800 rpm (depending on the outside air temperature and the load inside the storage), the steady operation time is, for example, 27 minutes, and the steady operation rate is, for example, 65%. That is, when the operation time of the previous compressor 18 is longer than the steady operation time or the operation rate of the compressor 18 is higher than the steady operation rate, the inverter control circuit 27 increases the rotational speed of the compressor 18, shortens the operation time of the compressor 18, and lowers the operation rate of the compressor 18. On the other hand, when the operation time of the previous compressor 18 is shorter than the steady operation time or the operation rate of the compressor 18 is lower than the steady operation rate, the inverter control circuit 27 decreases the rotational speed of the compressor 18, lengthens the operation time of the compressor 18, and increases the operation rate of the compressor 18. As a result, the inverter control circuit 27 brings the operation time of the compressor 18 closer to the steady operation time and the operation rate of the compressor 18 closer to the steady operation rate. At that time, the rotational speed of the compressor 18 also approaches the steady rotational speed.

[0073] As shown in FIG. 7, the inverter control circuit 27 may use the outside air temperature 156 of the refrigerator 1 during the current operation detected by the detection unit 26 to control the rotational speed 151 of the compressor 18 during the current operation. When using the outside air temperature 156 during the current operation, the inverter control circuit 27 controls the rotational speed 151 during the current operation based on the outside air temperature 156 during the current operation. For example, the inverter control circuit 27 increases the rotational speed 151 during the current operation as the outside air temperature 156 during the current operation increases. Thereby, when the temperature of the outside air rises and there is a possibility that the cooling capacity of the refrigeration cycle is insufficient during the current operation of the compressor 18, the cooling capacity of the refrigeration cycle can be increased.

[0074] As shown in FIG. 7, in order for the inverter control circuit 27 to control the rotational speed 151 of the compressor 18 during the current operation, the outside air temperature 154 during the past operation detected by the detection unit 26 during the past operation of the compressor 18 and the outside air temperature 156 during the current operation detected by the detection unit 26 during the current operation of the compressor 18 may be used. When the inverter control circuit 27 uses the outside air temperature 154 during the past operation and the outside air temperature 156 during the current operation, it controls the rotational speed 151 during the current operation based on the outside air temperature 154 during the past operation and the outside air temperature 156 during the current operation. For example, the inverter control circuit 27 controls the rotational speed 151 during the current operation based on the outside air temperature 164 during the previous operation detected by the detection unit 26 during the previous operation of the compressor 18 and the outside air temperature 156 during the current operation. The inverter control circuit 27 increases the rotational speed 151 during the current operation as the increase amount of the outside air temperature 156 during the current operation from the outside air temperature 154 during the past operation becomes larger. For example, the inverter control circuit 27 increases the rotational speed 151 during the current operation as the increase amount of the outside air temperature 156 during the current operation from the outside air temperature 164 during the previous operation becomes larger. Thereby, when the temperature of the outside air rises and there is a possibility that the cooling capacity of the refrigeration cycle is insufficient during the current operation of the compressor 18, the cooling capacity of the refrigeration cycle can be increased.

[0075] As shown in FIG. 7, the inverter control circuit 27 may use the stop time 153 at the previous stop of the compressor 18 to control the rotational speed 151 of the compressor 18 during the current operation. When using the stop time 153 at the previous stop, the inverter control circuit 27 controls the rotational speed 151 during the current operation based on the stop time 153 at the previous stop and the operation time 152 during the previous operation. For example, the inverter control circuit 27 controls the rotational speed 151 during the current operation based on the stop time 163 at the previous stop and the operation time 162 during the previous operation of the compressor 18. The inverter control circuit 27 decreases the rotational speed 151 during the current operation as the stop time 153 at the previous stop becomes longer. For example, the inverter control circuit 27 decreases the rotational speed 151 during the current operation as the stop time 163 at the previous stop becomes longer. Note that while the compressor 18 is stopped, no external power supply voltage is input to the inverter control circuit 27. Therefore, when the inverter control circuit 27 uses the stop time 153 at the previous stop, the control unit 142 and the storage unit 143 are backed up by a backup battery or the like to perform the process necessary to write the stop time of the compressor 18 to the storage unit 143. The stop time 153 at the previous stop may be an estimated time or a fixed time instead of the actually measured time. Also, when the control unit 142 is configured to be able to communicate with the outside, the stop time 163 at the previous stop of the compressor 18 can be calculated by communicating with an external server, router, etc. to obtain the current time and storing the obtained time in the storage unit 143.

[0076] As shown in FIG. 7, the inverter control circuit 27 may use the rotational speed 155 during the past operation of the compressor 18 to control the rotational speed 151 during the current operation of the compressor 18. When the inverter control circuit 27 uses the rotational speed 155 during the past operation, it controls the rotational speed 151 during the current operation based on the rotational speed 155 during the past operation. For example, the inverter control circuit 27 controls the rotational speed 151 during the current operation based on the rotational speed 165 during the previous operation of the compressor 18. The higher the rotational speed 155 during the past operation is, the higher the inverter control circuit 27 makes the rotational speed 151 during the current operation. For example, the higher the rotational speed 165 during the previous operation is, the higher the inverter control circuit 27 makes the rotational speed 151 during the current operation.

[0077] The rotational speed 155 during the past operation may be specified by a speed step associated with the rotational speed 155. The rotational speed 151 during the current operation may be specified by a speed step associated with the rotational speed 151. Specific examples of these speed steps will be described below.

[0078] The inverter control circuit 27 may perform the process of determining the rotational speed 151 during the current operation using an arithmetic expression, using a table, or using both an arithmetic expression and a table.

[0079] 1.6 Operation of the Refrigerator FIG. 8 is a flowchart showing the operation flow of the refrigerator according to the first embodiment.

[0080] The refrigerator 1 executes steps S101 to S107 shown in FIG. 8.

[0081] In step S101, a change occurs from a state where the external power supply voltage is not input to the first input terminal 81X and the second input terminal 81Y to a state where the external power supply voltage is input to the first input terminal 81X and the second input terminal 81Y. Such a change occurs when the temperature of the storage chamber 11A rises to a temperature higher than the set upper limit temperature and the thermostat 23 changes from the off state to the on state, or when the plug 40 is inserted into the outlet when the temperature of the storage chamber 11A is higher than the set upper limit temperature.

[0082] In the subsequent step S102, the control unit 142 acquires information used to control the rotation speed 151 during the current operation. When the control unit 142 uses the operation time 152 during the past operation, the stop time 153 during the past stop, the outside air temperature 154 during the past operation, and the rotation speed 155 during the past operation, the control unit 142 reads out the operation time 152 during the past operation, the stop time 153 during the past stop, the outside air temperature 154 during the past operation, and the rotation speed 155 during the past operation from the storage unit 143, respectively. When the control unit 142 uses the outside air temperature 156 during the current operation, the control unit 142 receives a signal indicating the outside air temperature 156 during the current operation from the detection unit 26.

[0083] By steps S101 and S102, the control unit 142 can acquire the information used to control the rotation speed 151 during the current operation in conjunction with the occurrence of a change from a state where the external power supply voltage is not input to the first input terminal 81X and the second input terminal 81Y to a state where the external power supply voltage is input to the first input terminal 81X and the second input terminal 81Y.

[0084] In the subsequent step S103, the control unit 142 determines the rotation speed 151 during the current operation based on the acquired information.

[0085] In the subsequent step S104, the control unit 142 starts the rotation of the compressor 18. The control unit 142 continues to rotate the compressor 18 at the determined rotation speed 151 during the current operation from when the rotation of the compressor 18 is started in step S104 until the rotation of the compressor 18 ends in step S106.

[0086] From step S101 to S104, while the external power supply voltage is not input to the first input terminal 81X and the second input terminal 81Y, the control unit 142 does not rotate the compressor 18. Also, when a change occurs from a state where the external power supply voltage is not input to the first input terminal 81X and the second input terminal 81Y to a state where the external power supply voltage is input to the first input terminal 81X and the second input terminal 81Y, the control unit 142 starts to rotate the compressor 18. At that time, the control unit 142 determines the rotation speed 151 during the current operation based on the acquired information.

[0087] In the subsequent step S105, the control unit 142 determines whether a change from a state where the external power supply voltage is input to the first input terminal 81X and the second input terminal 81Y to a state where the external power supply voltage is not input to the first input terminal 81X and the second input terminal 81Y is detected. This change occurs when the temperature of the storage chamber 11A drops to a temperature equal to or lower than the set lower limit temperature and the thermostat 23 changes from the conductive state to the cut-off state. If it is determined that this change is not detected, step S105 is executed again. Thus, until this change is detected, the control unit 142 continues to rotate the compressor 18. If it is determined that this change is detected, step S106 is executed.

[0088] In step S106, since the external power supply voltage is no longer input to the first input terminal 81X and the second input terminal 81Y, the drive voltage is no longer output from the first output terminal 82X, the second output terminal 82Y, and the third output terminal 82Z. Therefore, the rotation of the compressor 18 ends.

[0089] In the subsequent step S107, the control unit 142 writes information used to control the rotational speed during the next and subsequent operations of the compressor 18 into the storage unit 143. When the control unit 142 uses the rotational speed 151 during the current operation, the outside air temperature 156 during the current operation, and the operation time during the current operation, the control unit 142 writes the rotational speed 151 during the current operation, the outside air temperature 156 during the current operation, and the operation time during the current operation into the storage unit 143, respectively. The control unit 142 writes the information into the storage unit 143 within the effective time of the backup function exhibited when the voltages input to the first input terminal 81X and the second input terminal 81Y drop below the reference. As described above, the information used to control the rotational speed during the next and subsequent operations can be written into the storage unit 143.

[0090] 1.7 First Example of Process for Determining Rotational Speed of Compressor During Current Operation FIG. 9 is a diagram showing a first table used in a first example, a second example, and a third example of a process for determining the rotational speed of a compressor provided in the refrigerator according to the first embodiment during the current operation.

[0091] As shown in FIG. 9, the first table 171 includes speed step candidates "1",..., "12" and rotational speed candidates "1200 rpm",..., "3900 rpm".

[0092] The first table 171 associates the rotational speed candidates "1200 rpm",..., "3900 rpm" with the speed step candidates "1",..., "12", respectively.

[0093] FIG. 10 is a diagram showing a second table used in a first example of a process for determining the rotational speed of a compressor provided in the refrigerator according to the first embodiment during the current operation.

[0094] As shown in FIG. 10, the second table 172 includes temperature range candidates "less than 0°C",..., "40°C or higher" and standard operation time candidates "10 minutes",..., "60 minutes".

[0095] The second table 172 associates candidates for the standard operation time, "10 minutes",..., "60 minutes", with candidates for the temperature range, "less than 0°C",..., "40°C or higher", respectively.

[0096] FIG. 11 is a diagram showing a third table used in a first example of a process for determining the rotational speed of a compressor provided in the refrigerator of the first embodiment during the current operation.

[0097] As shown in FIG. 11, the third table 173 includes candidates for the range of the operation time difference, "-less than 15 minutes",..., "+15 minutes or more", and candidates for the amount of speed step change, "-2",..., "+2".

[0098] The third table 173 associates candidates for the amount of step change, "-2",..., "+2", with candidates for the range of the operation time difference, "-less than 15 minutes",..., "+15 minutes or more", respectively.

[0099] FIG. 12 is a diagram showing the content of a first example of a process for determining the rotational speed of a compressor provided in the refrigerator of the first embodiment during the current operation.

[0100] As shown in FIG. 12, the control unit 142 refers to the second table 172 and determines the candidate for the standard operation time associated with the candidate for the temperature range to which the outside air temperature 156 during the current operation belongs as the standard operation time 181.

[0101] Further, the control unit 142 obtains an operation time difference 182 ("operation time 162 during the previous operation" - "standard operation time 181") by subtracting the determined standard operation time 181 from the operation time 162 during the obtained previous operation.

[0102] Further, the control unit 142 refers to the third table 173 and determines the candidate for the amount of speed step change associated with the candidate for the range of the operation time difference to which the obtained operation time difference 182 belongs as the amount of speed step change 183.

[0103] Further, the control unit 142 makes a change indicated by the determined speed step change amount 183 to the speed step 184 at the previous operation that has been acquired, and determines the speed step 185 at the current operation of the compressor 18.

[0104] Also, the control unit 142 refers to the first table 171 and determines the rotation speed candidate 151 at the current operation corresponding to the speed step candidate that matches the determined speed step 185 at the current operation.

[0105] Thereby, the control unit 142 can determine the rotation speed 151 at the current operation based on the outside air temperature 156 at the current operation, the operation time 162 at the previous operation, and the speed step 184 at the previous operation.

[0106] 1.8 Second example of the process for determining the rotation speed at the current operation of the compressor FIG. 13 is a diagram showing a fourth table used in a second example of the process for determining the rotation speed at the current operation of the compressor provided in the refrigerator of the first embodiment.

[0107] As shown in FIG. 13, the fourth table 174 includes candidates for the range of the operation time change amount “less than -5 minutes”, ···, “5 minutes or more” and candidates for the speed step change amount “-1”, ···, “+1”.

[0108] The fourth table 174 associates the candidates for the speed step change amount “-1”, ···, “+1” with the candidates for the range of the operation time change amount “less than -5 minutes”, ···, “5 minutes or more”, respectively.

[0109] FIG. 14 is a diagram showing the content of a second example of the process for determining the rotation speed at the current operation of the compressor provided in the refrigerator of the first embodiment.

[0110] As shown in FIG. 14, the control unit 142 obtains the change amount of the operation time 187 (the operation time 162 at the previous operation - the operation time 186 at the operation before the previous operation) by subtracting the operation time 186 at the operation before the previous operation from the obtained operation time 162 at the previous operation.

[0111] Further, the control unit 142 refers to the fourth table 174 and determines the candidate for the speed step change amount corresponding to the candidate for the range of the operation time change amount to which the obtained operation time change amount 187 belongs as the speed step change amount 183.

[0112] Further, the control unit 142 performs the change indicated by the determined speed step change amount 183 on the obtained speed step 184 at the previous operation to determine the speed step 185 at the current operation.

[0113] Further, the control unit 142 refers to the first table 171 and determines the candidate for the rotation speed corresponding to the candidate for the speed step that matches the determined speed step 185 at the current operation as the rotation speed 151 at the current operation.

[0114] Thereby, the control unit 142 can determine the rotation speed 151 at the current operation based on the operation time 162 at the previous operation, the operation time 186 at the operation before the previous operation, and the speed step 184 at the previous operation.

[0115] The fourth table 174 is set such that when the operation time change amount 187 is positive and the operation time of the compressor 18 is increasing, the rotation speed 151 during the reverse operation increases, and when the operation time change amount 187 is negative and the operation time of the compressor 18 is decreasing, the rotation speed 151 at the current operation decreases. Thereby, the cooling capacity of the refrigeration cycle can be varied according to the variation in the load applied to the refrigeration cycle. For example, when the number of times the door 15 is opened and closed is large, or when a storage item having a large heat capacity is stored in the storage chamber 11A, the cooling capacity of the refrigeration cycle can be increased.

[0116] The second example can be used in combination with the first example.

[0117] 1.9 Third Example of Process for Determining Rotation Speed during Current Operation of Compressor FIG. 15 is a diagram showing a fifth table used in a third example of a process for determining the rotation speed during the current operation of a compressor provided in the refrigerator of the first embodiment.

[0118] As shown in FIG. 15, the fifth table 175 includes candidates for temperature ranges “less than 0° C.”, ···, “40° C. or higher”, candidates for ranges of change in operation time “less than -5 minutes”, ···, “5 minutes or more”, and candidates for speed steps “3”, ···, “11”.

[0119] The fifth table 175 associates candidates for speed steps “3”, ···, “11” with candidates for temperature ranges “less than 0° C.”, ···, “40° C. or higher”, respectively.

[0120] The control unit 142 refers to the table in FIG. 15 and sets the candidate for the speed step associated with the candidate for the temperature range to which the outside air temperature 156 belongs as the speed step during the current operation.

[0121] Also, the control unit 142 refers to the first table 171 and determines the candidate for the rotation speed associated with the candidate for the speed step that matches the determined speed step during the current operation as the rotation speed 151 during the current operation.

[0122] As a result, since the rotation speed 151 is determined only by the outside air temperature 156, time measurement and storage are not required.

[0123] 1.10 Defrosting FIG. 16 is a block diagram of a defrosting mechanism that may be provided in the refrigerator of the first embodiment.

[0124] The refrigerator 1 may be provided with a defrosting mechanism 191 illustrated in FIG. 16. The defrosting mechanism 191 includes an operation time counter 201 and a defrosting heater 202.

[0125] The operation time counter 201 counts the operation time during which the compressor 18 has been operated. The counted operation time increases as time elapses while the compressor 18 is operating, and does not increase even if time elapses while the compressor 18 is stopped. Further, when the defrost heater 202 defrosts the storage chamber 11A, the operation time counter 201 resets the counted operation time to 0. Therefore, the time during which the compressor 18 has been operated since the storage chamber 11A was last defrosted can be specified from the counted operation time.

[0126] The defrost heater 202 defrosts the storage chamber 11A in synchronization with the counted operation time by the operation time counter 201 reaching the set time. The set time is, for example, 8 hours. Thereby, when it is estimated that frost has formed in the storage chamber 11A because the operation time of the compressor 18 has become long, the storage chamber 11A can be defrosted.

[0127] The present disclosure is not limited to the above-described embodiments, and may be replaced with a configuration that is substantially the same as the configuration shown in the above-described embodiments, a configuration that exhibits the same operational effects, or a configuration that can achieve the same purpose.

Description of Reference Numerals

[0128] 1 Refrigerator, 11 Housing, 11A Storage Room, 11B Opening, 11D Freezer, 11E Refrigerator Compartment, 12 Shelf Board, 13 Tray, 14 Dial, 15 Door, 15A Storage Pocket, 16 Chassis, 16A Bottom Space, 17 Earth Terminal, 18 Compressor, 19 Power Cord, 20 First Terminal Pair, 21 Surge Absorption Circuit, 22 Second Terminal Pair, 23 Thermostat, 24 Third Terminal Pair, 25 Terminal, 26 Detection Unit, 27 Inverter Control Circuit, 28 Door Switch, 29 Indoor Light, 20X First Terminal, 20Y Second Terminal, 22X First Terminal, 22Y Second Terminal, 24X First Terminal, 24Y Second Terminal, 40 Plug, 41 First Cord, 42 Second Cord, 51 First Plug Blade, 52 Second Plug Blade, 61 Input Terminal Pair, 62 Output Terminal Pair, 63 Earth Terminal, 61X First Input Terminal, 61Y Second Input Terminal, 62X First Output Terminal, 62Y Second Output Terminal, 71 First External Terminal, 72 Second External Terminal, 73 Earth Terminal, 74 Capillary, 75 Outer Shell, 81 Input Terminal Pair, 82 Output Terminal Group, 83 Earth Terminal, 81X First Input Terminal, 81Y Second Input Terminal, 82X First Output Terminal, 82Y Second Output Terminal, 82Z Third Output Terminal, 91 Input Terminal Group, 91X First Input Terminal, 91Y Second Input Terminal, 91Z Third Input Terminal, 92 Earth Terminal, 111 First Terminal, 112 Second Terminal, 121 First Terminal, 122 Second Terminal, 131 Temperature Detection Unit, 141 Drive Circuit, 142 Control Unit, 143 Memory Unit, 151 Rotation Speed during Current Operation, 152 Operation Time during Past Operation, 153 Stop Time during Past Stop, 154 Temperature during Past Operation, 155 Rotation Speed during Past Operation, 156 Temperature during Current Operation, 162 Operation Time during Previous Operation, 163 Stop Time during Previous Stop, 165 Rotation Speed during Previous Operation, 171 First Table, 172 Second Table, 173 Third Table, 174 Fourth Table, 175 Fifth Table, 181 Standard Operation Time, 182 Operation Time Difference, 183 Speed Step Change Amount, 184 Speed Step during Previous Operation, 185 Speed Step during Current Operation, 186 Operation Time during the Operation before the Previous One, 187 Operation Time Change Amount, 191 Defrosting Mechanism, 201 Operation Time Counter, 202 Defrosting Heater.

Claims

1. A housing formed with a storage room, a first external terminal to which an external power supply voltage is input, and a second external terminal, and a thermostat in which the second external terminal becomes a conduction state in which the second external terminal conducts with the first external terminal or a cutoff state in which the second external terminal does not conduct with the first external terminal according to the temperature of the storage room, a compressor, an AC voltage input terminal electrically connected to the second external terminal, a control circuit is driven by an AC voltage input to the AC voltage input terminal, determines the rotation speed during the current operation of the compressor when input to the AC voltage input terminal, operates the compressor at the rotation speed while the external power supply voltage is input to the AC voltage input terminal, and stops the control circuit and the compressor while the external power supply voltage is not input to the AC voltage input terminal, an inverter control circuit, A refrigerator comprising.

2. The inverter control circuit changes the rotation speed during the current operation based on the operation time during past operations The refrigerator according to claim 1.

3. The operation time during the past operation is the operation time during the previous operation The refrigerator according to claim 2.

4. Comprising a detection unit that detects the temperature of the outside air of the refrigerator, The inverter control circuit controls the rotation speed during the current operation based on the temperature detected by the detection unit during the current operation The refrigerator according to claim 1.

5. The inverter control circuit controls the rotation speed during the current operation from the difference between the temperature detected by the detection unit during the past operation and the temperature detected by the detection unit during the current operation The refrigerator according to claim 4.

6. The inverter control circuit, a storage unit, In conjunction with the change from the state in which the external power supply voltage is input to the AC voltage input terminal to the state in which the external power supply voltage is not input to the AC voltage input terminal, the operation time during the current operation of the compressor is written to the storage unit, and the external power supply voltage is input to the AC voltage input terminal. A control unit that reads the operation time during the past operation from the storage unit in conjunction with the change from the state in which the voltage is not input to the state in which the external power supply voltage is input to the AC voltage input terminal, Comprising The refrigerator according to any one of claims 1 to 3.

7. The inverter control circuit controls the rotation speed during the current operation based on the stop time at the past stop of the compressor and the operation time during the past operation The refrigerator according to claim 1.

8. The stop time at the past stop is the stop time at the previous stop The refrigerator according to claim 7.

9. The inverter control circuit calculates an operation rate from the operation time during the past operation and the stop time at the past stop of the compressor, and controls the rotational speed during the current operation based on the operation rate. The refrigerator according to claim 1.

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