refrigerator

Abstract

To provide a refrigerator which can perform processing for improving a frosting state when the generation of a frost is determined by determining the presence or absence of the frosting of a blower to a rotary vane.SOLUTION: A refrigerator of this embodiment comprises a box body, a cooler, a blower, a frosting determination part and an operation control part. The box body includes a storage chamber. The cooler is arranged in the box body. The blower sends cold air which is cooled by the cooler. The frosting determination part determines the presence or absence of frosting to a rotary vane on the basis of a continuation situation of a state that detection is made of at least either the fact that a control signal of feedback control to the blower indicates an increase of a rotational speed of the rotary vane with respect to the fact that a target value of the rotational speed of the rotary vane of the blower is constant, or the fact that a measurement value of the rotational speed is decreased with respect to the fact that the control signal indicates the constant speed rotation of the rotary vane. When a prescribed condition including the determination of the frosting to the rotary vane is satisfied, the operation control part performs defrosting processing to the rotary vane.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] An embodiment of the present invention relates to a refrigerator. [Background technology]

[0002] Frost may form on the rotor of a blower that blows cool air inside a refrigerator. When frost forms on the rotor, for example, even if the blower is stopped and then restarted, the frost condition may not improve. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-61709 A Summary of the Invention [Problem to be solved by the invention]

[0004] The problem that the present invention aims to solve is to provide a refrigerator that can determine whether or not frost has formed on a blower rotor and, if it is determined that frost has formed, can perform processing to improve the frost condition. [Means for solving the problem]

[0005] The refrigerator according to the embodiment includes a housing, a cooler, a blower, a frost determination unit, and an operation control unit. A frost information recording unit and a frost notification unitThe housing includes a storage chamber. The cooler is provided in the housing. The blower blows cool air cooled by the cooler. The frost determination unit determines the presence or absence of frost on the rotor blades based on a continuation state in which at least one of the following is detected: a target value of the rotation speed of the rotor blades of the blower is constant while a control signal of a feedback control for the blower instructs an increase in the rotation speed of the rotor blades, or the control signal instructs constant speed rotation of the rotor blades while a measured value of the rotation speed is decreasing. The operation control unit performs a defrosting process on the rotor blades when predetermined conditions are satisfied, including a determination that frost is present on the rotor blades. The frost information recording unit records frost information indicating frost on the rotor when it is determined that frost has formed on the rotor. The frost notification unit notifies that frost is frequently forming on the rotor when it is determined based on the frost information that frost has formed on the rotor more than a predetermined number of times within a predetermined time. [Brief description of the drawings]

[0006] [Figure 1] FIG. 2 is a front view showing the refrigerator according to the embodiment. [Diagram 2] 2 is a cross-sectional view taken along line F3-F3 of the refrigerator shown in FIG. 1. [Diagram 3] FIG. 2 is a diagram showing the external shape of a blower according to the embodiment. [Figure 4] FIG. 2 is a block diagram showing a part of the configuration of a control unit according to the embodiment. [Diagram 5] FIG. 4 is a diagram showing an example of control of a blower by an operation control unit of the embodiment. [Figure 6] 4 is a graph showing an example of characteristics of a DC motor according to an embodiment. [Figure 7] FIG. 4 is a diagram showing an example of a decrease in rotation speed due to frost on a rotor blade in the embodiment. [Figure 8] 10 is a graph showing an example of change of a lower limit threshold of the rotation speed of the rotor blades by a threshold changing unit of the embodiment. [Figure 9] 5 is a flowchart illustrating an example of a process for controlling an operation of a blower by a control unit of the embodiment. [Figure 10] 5 is a flowchart illustrating an example of a process for controlling an operation of a blower by a control unit of the embodiment. [Figure 11] 6 is a flowchart illustrating an example of a processing procedure in which a control unit of the embodiment updates a control command value. [Figure 12] 5 is a flowchart illustrating an example of a process performed by a frost determination unit of the embodiment to determine whether or not frost has formed on a rotor blade. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] Hereinafter, a refrigerator according to an embodiment will be described with reference to the drawings. In the following description, components having the same or similar functions are denoted by the same reference numerals. Furthermore, duplicated descriptions of those components may be omitted. "Based on XX" means "based on at least XX" and may include a case where the component is based on another element in addition to XX. "Based on XX" is not limited to a case where XX is directly used, and may include a case where the component is based on XX that has been subjected to calculation or processing. "XX or YY" is not limited to a case where either XX or YY is used, and may include a case where both XX and YY are used. This also applies to a case where there are three or more selective elements. "XX" and "YY" are any element (for example, any information).

[0008] 1 is a front view showing refrigerator 100. Refrigerator 100 includes, for example, a housing 1, a refrigerator compartment door 2a, a vegetable compartment door 4a, an ice making compartment door 5a, a small freezer compartment door 6a, a large freezer compartment door 7a, a refrigerator compartment door opening / closing detection unit 2b, a vegetable compartment door opening / closing detection unit 4b, an ice making compartment door opening / closing detection unit 5b, a small freezer compartment door opening / closing detection unit 6b, a large freezer compartment door opening / closing detection unit 7b, and an input / output device 8.

[0009] The housing 1 has an upper wall 1a, a lower wall 1b, a left side wall 1c, a right side wall 1d, and a rear wall 1e (see FIG. 2), and is formed in a box shape with an open front. The housing 1 includes, for example, an inner box forming the inner surface of the housing 1, an outer box forming the outer surface of the housing 1, and a foam insulation material provided between the inner box and the outer box, and has thermal insulation properties. Inside the housing 1, a plurality of partitions 1f, 1g, and 1h are provided that divide the inside of the housing 1 into a plurality of storage chambers, which will be described later.

[0010] The housing 1 includes a plurality of storage compartments. The plurality of storage compartments include, for example, a refrigerator compartment 2, a chilled compartment 3, a vegetable compartment 4, an ice-making compartment 5, a small freezer compartment 6, and a large freezer compartment 7. In this embodiment, the refrigerator compartment 2 is located at the top, the vegetable compartment 4 is located below the refrigerator compartment 2, the ice-making compartment 5 and the small freezer compartment 6 are located below the vegetable compartment 4, and the large freezer compartment 7 is located below the ice-making compartment 5 and the small freezer compartment 6. The chilled compartment 3 is provided inside the refrigerator compartment 2, and is at least partially partitioned from other areas of the refrigerator compartment 2 by a shelf, a lid, or the like.

[0011] The openings of the multiple storage compartments are each closed by a door so that they can be opened and closed. The opening of refrigerator compartment 2 is closed by refrigerator compartment doors 2a provided on the left and right of the opening so that they can be opened and closed. The opening of vegetable compartment 4 is closed by vegetable compartment door 4a so that they can be opened and closed. The opening of ice-making compartment 5 is closed by ice-making compartment door 5a so that they can be opened and closed. The opening of small freezer compartment 6 is closed by small freezer compartment door 6a so that they can be opened and closed. The opening of large freezer compartment 7 is closed by large freezer compartment door 7a so that they can be opened and closed. Thus, refrigerator compartment door 2a, vegetable compartment door 4a, ice compartment door 5a, small freezer compartment door 6a, and large freezer compartment door 7a are examples of storage compartment doors.

[0012] The door opening / closing detection unit is provided at a position corresponding to each door and detects the opening / closing of each door. The door opening / closing detection unit may be configured to include a push button switch that is pressed to close (ON) when the door is closed, and the opening / closing of the door may be detected by the opening / closing of this push button switch. However, the configuration of the door opening / closing detection unit is not limited to this, and various configurations capable of detecting the opening / closing of the door may be used.

[0013] The refrigerator door opening / closing detection unit 2b detects whether the refrigerator door 2a is open or closed. The vegetable door opening / closing detection unit 4b detects whether the vegetable door 4a is open or closed. The ice-making door opening / closing detection unit 5b detects whether the ice-making door 5a is open or closed. The small freezer door opening / closing detection unit 6b detects whether the small freezer door 6a is open or closed. The large freezer door opening / closing detection unit 7b detects whether the large freezer door 7a is open or closed. Thus, the refrigerator compartment door opening / closing detection unit 2b, the vegetable compartment door opening / closing detection unit 4b, the ice-making compartment door opening / closing detection unit 5b, the small freezer door opening / closing detection unit 6b, and the large freezer door opening / closing detection unit 7b are examples of door opening / closing detection units.

[0014] The input / output device 8 is provided on the housing 1 or the door. The input / output device 8 notifies a user (a user of the refrigerator 100) and accepts user operations. The configuration of the input / output device 8 is not limited to a specific configuration. For example, the input / output device 8 may be configured to include a display device and a loudspeaker, and may notify the user by displaying an image and / or outputting sound. The input / output device 8 may also be configured to include a touch sensor provided on the display screen of the display device, and detecting a user operation by a finger or the like.

[0015] Alternatively, the input / output device 8 may be provided with an indicator light such as an LED (Light Emitting Diode) and may notify the user by turning on or off the indicator light. Also, the input / output device 8 may be configured to include a push button switch and may accept a user operation by pressing the push button switch.

[0016] Fig. 2 is a cross-sectional view taken along line F3-F3 of refrigerator 100 shown in Fig. 1. In addition to the components shown in Fig. 1, refrigerator 100 includes blower 9, refrigerator compartment temperature measuring unit 10, freezer compartment temperature measuring unit 11, outdoor air temperature measuring unit 12, humidity measuring unit 13, cool air flow adjusting unit 14, cooler 15, compressor 16, control unit 17, defrost heater 18, and wireless communication unit 19 shown in Fig. 2.

[0017] Compressor 16 compresses the refrigerant. The refrigerant flows into compressor 16 in a gaseous state and is compressed, and then is cooled and liquefied by heat exchange with air outside housing 1. The liquefied refrigerant flows into cooler 15. The air outside housing 1 is also referred to as outside air. Cooler 15 is provided inside housing 1. Cooler 15 cools the air inside housing 1. Specifically, the refrigerant that flows into cooler 15 evaporates. When the refrigerant evaporates, it takes heat of evaporation from the air around cooler 15 (air inside housing 1), thereby cooling the air around cooler 15.

[0018] The blower 9 blows the air cooled by the cooler 15. The air cooled by the cooler 15 is also referred to as cool air. 3 is a diagram showing the external shape of blower 9. Blower 9 is configured to include, for example, a direct current motor (DC motor) 91 and a propeller (propeller) 92. Propeller 92 is provided rotatably around the rotation shaft of DC motor 91. DC motor 91 rotates by receiving a supply of electric power, thereby rotating propeller 92. In the following, it is assumed that the rotation speed of DC motor 91 and the rotation speed of rotor 92 are the same, and controlling the rotation speed of DC motor 91 and controlling the rotation speed of rotor 92 are treated as the same thing.

[0019] However, the rotation shaft of the DC motor 91 and the rotation shaft of the rotor 92 may be different. Furthermore, the rotation speed of the DC motor 91 and the rotation speed of the rotor 92 may be different. For example, a gear may be provided between the rotation shaft of the DC motor 91 and the rotation shaft of the rotor 92, so that the rotational force generated by the DC motor 91 is transmitted to the rotor 92 through the gear.

[0020] The defrost heater 18 defrosts the blower 9 and / or the cooler 15. Specifically, when frost forms on the blower 9 and / or the cooler 15, the defrost heater 18 heats according to the control of the control unit 17, thereby heating the air around the defrost heater 18, and the heat of this air defrosts the blower 9 and / or the cooler 15.

[0021] The cold air flow adjustment unit 14 is provided in the flow path of the cold air to adjust the flow of the cold air. In the example of Fig. 2, the cold air flow adjustment unit 14 is provided between the ice making compartment 5 and the vegetable compartment 4, and adjusts the flow rate of the cold air from the freezer side to the refrigerator side. The freezer side here is a space that includes the ice making compartment 5, the small freezer compartment 6, and the large freezer compartment 7 and is cooled to a temperature below 0 degrees. The refrigerator side is a space that includes the refrigerator compartment 2, the chilled compartment 3, and the vegetable compartment 4 and is cooled to a temperature higher than 0 degrees or close to 0 degrees. For example, the cool air flow adjustment unit 14 may be configured to include a shutoff valve, and the flow rate of the cool air may be adjusted according to the ratio of the time the shutoff valve is open to the time it is closed. The cool air flow adjustment unit 14 is also called a damper.

[0022] The refrigerator compartment temperature measurement unit 10 measures the temperature of the air in the refrigerator compartment 2. The freezer compartment temperature measurement unit 11 measures the temperature of the air in the large freezer compartment 7. The outdoor air temperature measurement unit 12 measures the temperature of the outdoor air. The refrigerator compartment temperature measurement unit 10, the freezer compartment temperature measurement unit 11, and the outdoor air temperature measurement unit 12 are collectively referred to as temperature measurement units. The humidity measuring unit 13 measures the humidity of the outside air.

[0023] The wireless communication unit 19 communicates with other devices (devices other than the refrigerator 100). For example, the wireless communication unit 19 may communicate with a smartphone carried by a user to transmit various information and receive instructions from the user. Control unit 17 acquires status information of each part of refrigerator 100 and controls each part of refrigerator 100. The status information of a certain part here is information indicating the status of that part. Control unit 17 is configured using a computer such as a microcomputer. Alternatively, control unit 17 may be configured using hardware designed specifically for control unit 17, such as an application specific integrated circuit (ASIC), a programmable logic device (PLD), or a field programmable gate array (FPGA). The storage unit 20 stores various information. The storage unit 20 is configured using, for example, a non-volatile memory element (Memory Device). The storage unit 20 may be configured as a part of the control unit 17, or may be configured externally to the control unit 17.

[0024] 4 is a block diagram showing part of the configuration of the control unit 17. The control unit 17 includes, for example, an operation control unit 171, a frost formation determination unit 172, a frost formation information recording unit 173, a door opening / closing information recording unit 174, a notification control unit 175, a threshold value changing unit 176, and an outside temperature and humidity information recording unit 177. The control unit 17 also acquires information on user operations received by the input / output device 8, and controls the input / output device 8 to make a notification. The control unit 17 also acquires information on the open / close status of the doors from each of the refrigerator door open / close detection unit 2b, the vegetable door open / close detection unit 4b, the ice-making door open / close detection unit 5b, the small freezer door open / close detection unit 6b, and the large freezer door open / close detection unit 7b. The control unit 17 also acquires measured values ​​of temperature from each of the refrigerator temperature measurement unit 10, the freezer temperature measurement unit 11, and the outside air temperature measurement unit 12. The control unit 17 also acquires measured values ​​of humidity from the humidity measurement unit 13. The control unit 17 also acquires information received by the wireless communication unit 19, and controls the wireless communication unit 19 to transmit various information. The control unit 17 also writes various information to the memory unit 20, and reads out various information stored in the memory unit 20. The control unit 17 also controls each of the blower 9, the cool air flow adjustment unit 14, the compressor 16, and the defrost heater 18. The control unit 17 also obtains status information of each of the blower 9 and the compressor 16.

[0025] The operation control unit 171 controls each part of the refrigerator 100. Fig. 5 is a diagram showing an example of control of blower 9 by operation control unit 171. Operation control unit 171 includes, for example, signal conversion unit 271, subtractor 272, speed correction unit 273, and square wave counting unit 274. Blower 9 includes, for example, DC motor 91 and rotor 92 shown in Fig. 3, as well as power supply circuit 93 and blower driving integrated circuit 94 shown in Fig. 5. Blower driving integrated circuit 94 includes, for example, speed setting unit 95 and square wave generating unit 96.

[0026] The operation control unit 171 controls the rotation speed of the DC motor 91 by feedback control. In the example of Fig. 5, the operation control unit 171 outputs a control signal to the blower 9 as a PWM (Pulse Width Modulation) signal. In addition, the blower 9 outputs a measured value of the rotation speed of the DC motor 91 as an FG (Frequency Generator) signal.

[0027] A PWM signal is a signal that expresses two signal values, "high" and "low," as a square wave (Pulse Wave). With a PWM signal, a control command value in the range from 0 to 1 ([0,1]) can be expressed as the percentage of time that the signal value is "high." For example, a control command value of 1 (i.e., 100%) can be expressed by maintaining the value of the PWM signal at "high." Conversely, a control command value of 0 (i.e., 0%) can be expressed by maintaining the value of the PWM signal at "low." Control that uses a PWM signal is called PWM control.

[0028] The percentage of time that the PWM signal value is "high" is also called the duty ratio or duty cycle. For example, if the PWM signal value remains "high," the duty ratio is 100%. If the PWM signal value remains "low," the duty ratio is 0%.

[0029] 5, the PWM signal is used as a signal representing a command value for the rotation speed of the DC motor 91 in a steady state. The operation control unit 171 represents the rated maximum rotation speed of the DC motor 91 by maintaining the value of the PWM signal at "high", and represents the stop (rotation speed 0) of the DC motor 91 by maintaining the value of the PWM signal at "low". The operation control unit 171 then represents the command value for the rotation speed of the DC motor 91 as a ratio to the rated maximum rotation speed, based on the percentage of time during which the value of the PWM signal is "high".

[0030] The FG signal is a signal that represents the rotation speed by the number of square waves per unit time. In the example of Fig. 5, the fan 9 outputs two square waves as the FG signal every time the DC motor 91 rotates once. In this way, the fan 9 outputs the FG signal that represents the rotation speed of the DC motor 91 by the number of square waves per unit time. For example, if the number of square waves of the FG signal per second is 40, this indicates that the DC motor 91 rotates 20 times per second, and the rotation speed is 1200 rpm (Revolutions Per Minute). However, the control signal output by the operation control unit 171 is not limited to a specific type. The signal indicating the measured value of the rotation speed of the DC motor 91 output by the blower 9 is also not limited to a specific type.

[0031] The signal conversion unit 271 receives an input of a target rotation speed for the DC motor 91 and converts it into data in a format that can be calculated by the subtractor 272 . The data representing the target rotation speed input to the signal conversion unit 271 is represented as "Fcom." Fcom is represented, for example, in revolutions per minute (rpm). Moreover, data representing the target rotation speed output by the signal conversion unit 271 is represented as "Ncom." Ncom is represented, for example, by a target value of the number of square waves included in the FG signal per unit time.

[0032] The square wave counter 274 counts the number of FG signals from the blower 9 per unit time. Data indicating the counting result by the square wave counter 274 is denoted as "Nret." Nret indicates a measured value of the number of rotations of the DC motor 91 per unit time. The subtractor 272 subtracts the value of Nret from the value of Ncom. The result of the subtraction by the subtractor 272 is denoted as "ΔN." ΔN represents the difference obtained by subtracting the measured value from the target value of the rotation speed of the DC motor 91.

[0033] The speed correction unit 273 generates a PWM signal based on ΔN. For example, the speed correction unit 273 changes the proportion of time during which the value of the PWM signal is "high" by the value of ΔN multiplied by a predetermined coefficient. When ΔN is a positive value, it indicates that the measured rotation speed of the DC motor 91 is smaller than the target value. In this case, the speed correction unit 273 increases the proportion of time during which the value of the PWM signal is "high" by a proportion proportional to the magnitude of ΔN. However, if the value of the PWM signal remains "high" (duty ratio 100%), the control command value cannot be increased any further. If the value of the PWM signal remains "high", the speed correction unit 273 maintains the value of the PWM signal as "high" even when ΔN is a positive value.

[0034] When ΔN is a negative value, it indicates that the measured rotation speed of the DC motor 91 is greater than the target value. In this case, the speed correction unit 273 reduces the proportion of time during which the value of the PWM signal is "high" by a proportion proportional to the magnitude of ΔN. However, it is not appropriate to operate the DC motor 91 at a rotation speed lower than the rated minimum rotation speed. For this reason, when the PWM signal represents the rated minimum rotation speed of the DC motor 91, even when ΔN is a negative value, the speed correction unit 273 maintains the proportion of time during which the value of the PWM signal is "high" at the proportion representing the rated minimum rotation speed.

[0035] The power supply circuit 93 receives an instruction to supply power from the operation control unit 171, and outputs power of a voltage intended for the fan driving integrated circuit 94 to the fan driving integrated circuit 94. The configuration of the power supply circuit 93 is not limited to a specific one. For example, the power supply circuit 93 may be configured using a FET (Field Effect Transistor), but is not limited thereto. The power supply circuit 93 supplies power according to the rating of the fan drive integrated circuit 94, such as a power supply voltage of 12 volts (V) or 14 volts.

[0036] The fan driving integrated circuit 94 controls the DC motor 91 based on a control signal from the operation control unit 171, and also measures the rotation speed of the DC motor 91. The fan driving integrated circuit 94 may be integrated into one integrated circuit (IC). In the example of FIG. 5, the fan driving integrated circuit 94 receives power from the power supply circuit 93. The speed setting unit 95 sets the rotation speed of the DC motor 91 to the rotation speed indicated by the PWM signal. For example, the speed setting unit 95 sets the voltage value of the power supplied to the DC motor 91 to a value corresponding to the proportion of time during which the value of the PWM signal is "high."

[0037] The square wave generating unit 96 measures the rotation speed of the DC motor 91 and outputs the measurement result as an FG signal. For example, as described above for the blower 9, the square wave generating unit 96 outputs two square waves as an FG signal for each rotation of the DC motor 91. As a result, the square wave generating unit 96 outputs an FG signal that represents the rotation speed of the DC motor 91 as the number of square waves per unit time.

[0038] Fig. 6 is a graph showing an example of the characteristics of the DC motor 91. Fig. 6 shows the relationship between the duty ratio of the PWM signal output by the speed correction unit 273 and the rotation speed of the DC motor 91 in a steady state. The horizontal axis of the graph in Fig. 6 shows the duty ratio in the unit of %, and the vertical axis shows the rotation speed of the DC motor 91 in the unit of rpm.

[0039] 6 shows an example in which a rated minimum rotation speed is set for the DC motor 91, and the straight line portion of the graph (line L11) shows the relationship between the duty ratio and the rotation speed in the range from the rated minimum rotation speed to the rated maximum rotation speed. The rotation speed increases monotonically according to the duty ratio.

[0040] The rotation speed when the duty ratio is 100% indicates the rated maximum rotation speed, which is 2600 rpm. The transition point between the straight line portion (line L11) and the dashed line portion (line L12) of the graph indicates the rated minimum rotation speed. The rated minimum rotation speed is 1000 rpm when the duty ratio is 35%.

[0041] In the configuration of the control unit 17 shown in Fig. 4, the frost determination unit 172 determines whether or not frost has formed on the rotor blades 92. When frost has formed on the rotor blades 92, the rotation speed of the rotor blades 92 decreases due to the weight of the frost. When the target value of the rotation speed of the rotor 92 of the blower 9 is constant, it is considered that the operation control unit 171 instructs the blower 9 to increase the rotation speed of the rotor 92 by a control signal of the feedback control to keep the rotation speed of the rotor 92 constant against the formation of frost on the rotor 92. For example, in Fig. 5, while Ncom instructs a constant rotation speed, it is considered that the rotation speed of the DC motor 91 decreases due to the formation of frost on the rotor 92. In this case, the value of ΔN increases due to the decrease in the rotation speed of the DC motor 91, and the speed correction unit 273 increases the duty ratio of the PWM signal.

[0042] Furthermore, when the operation control unit 171 outputs a control signal instructing the rotor 92 to rotate at a constant speed, it is considered that the rotation speed of the rotor 92 will decrease due to frost on the rotor 92. For example, in Fig. 5, when the speed correction unit 273 outputs a PWM signal with a duty ratio of 100%, it is considered that the rotation speed of the DC motor 91 will decrease due to frost on the rotor 92. This decrease in rotation speed is represented by a decrease in the number of square waves per unit time in the FG signal.

[0043] Thus, the frost determination unit 172 determines the presence or absence of frost on the rotor 92 based on the continuation of a state in which at least one of the following is detected: a control signal of the feedback control for the blower 9 instructs an increase in the rotation speed of the rotor 92 while the target value of the rotation speed of the rotor 92 of the blower 9 is constant, or a control signal instructs constant speed rotation of the rotor 92 while the measured value of the rotation speed is decreasing. Determining that frost exists is also referred to as detecting frost.

[0044] FIG. 7 is a diagram showing an example of a decrease in rotation speed due to frost on the rotor blades 92. In FIG. 7, in the time period from 0 minutes to 7 minutes, no frost forms on the rotor blades 92, and the blower 9 is in a normal state. In the normal state, the operation control unit 171 sets the duty ratio of the PWM signal to 80.0%, and the DC motor 91 rotates at a rotation speed of 2200 rpm, which is set as the target rotation speed.

[0045] On the other hand, after 8 minutes, frost forms on the rotor blades 92. In the time period from 8 minutes to 31 minutes, the operation control unit 171 increases the duty ratio of the PWM signal to maintain the target rotation speed of 2200 rpm. In addition, at 16 minutes, the frost determination unit 172 detects frost on the rotor blades 92. Fig. 7 shows an example in which, even after frost is detected, the operation control unit 171 maintains the same target rotation speed as before frost was detected.

[0046] At 32 minutes, the duty ratio reaches 100%, and the operation control unit 171 cannot increase the duty ratio any further. Therefore, in the time period from 32 minutes onwards, the operation control unit 171 maintains the duty ratio at 100%. However, the rotation speed of the rotor 92 is decreasing due to frost formation.

[0047] 7, changes in the case of frost formation on the rotor blades 92 occur relatively slowly over time. When the operation control unit 171 increases the duty ratio to maintain a constant target rotation speed, as illustrated in the time period from 8 minutes to 31 minutes, the increase in the duty ratio is relatively slow. When the rotation speed of the rotor blades 92 decreases while the duty ratio is constant, as illustrated in the time period from 32 minutes onwards, the decrease in the rotation speed is relatively slow.

[0048] For this reason, the frost determination unit 172 can detect frost on the rotor blades 92 by continuously observing the above-mentioned changes for a certain period of time or more, and distinguish it from an abnormality in the rotation speed due to a malfunction of the blower 9. For example, the frost determination unit 172 determines whether or not frost has formed on the rotor 92 when a state in which at least one of the following is detected for a predetermined time or longer: the target value of the rotation speed of the rotor 92 of the blower 9 is constant, while the control signal of the feedback control for the blower 9 instructs an increase in the rotation speed of the rotor 92, or the control signal instructs the rotor 92 to rotate at a constant speed, while the measured value of the rotation speed is decreasing.

[0049] When the frost formation determination unit 172 determines that frost has formed on the rotor 92, the frost formation information recording unit 173 records frost formation information indicating frost formation on the rotor 92. Recording the information here may also mean storing the information in the storage unit 20. For example, the frost information recording unit 173 generates frost information linking a message indicating that frost has been detected on the rotor blades 92, the time when the frost was detected, and an index value indicating the degree of frost such as ΔN in Fig. 5, and stores the frost information in the storage unit 20. While frost is detected on the rotor blades 92, the frost information recording unit 173 may generate the frost information and store it in the storage unit 20 at regular time intervals, for example, every minute. Alternatively, the frost information recording unit 173 may generate frost information including the time when frost on the rotor blades 92 began to be detected and the time until frost was no longer detected, and store the frost information in the memory unit 20.

[0050] The door opening / closing information recording unit 174 records the door opening / closing information indicating the opening / closing status of the door based on the detection result of the door opening / closing detection unit. For example, every time it is detected that any of the refrigerator door 2a, the vegetable door 4a, the ice-making door 5a, the small freezer door 6a, or the large freezer door 7a is opened, the door opening / closing information recording unit 174 generates door opening / closing information and stores it in the memory unit 20. The door opening / closing information recording unit 174 may generate frost formation information that is linked to the name of the opened door, a message indicating that it was detected that the door was opened, the time the door was opened, and the time from when the door was opened to when it is closed, and store it in the memory unit 20. The act of a door being opened can also be written as "door agaru".

[0051] The outside temperature and humidity information recording unit 177 records information on the outside temperature and humidity when the door is opened or closed (particularly when the door is opened). The information on the outside temperature and humidity is also referred to as outside temperature and humidity information. The outside temperature and humidity information recording unit 177 may store in the memory unit 20 the outside temperature (°C) measured by the outside temperature measuring unit 12 and the outside humidity (%) measured by the humidity measuring unit 13 together with information indicating that the door has been opened.

[0052] A high outside temperature indicates that the air has a high ability to retain moisture. Also, high humidity means that the moisture contained in the air is highly saturated. Therefore, outside temperature / humidity information recording unit 177 can record information on the air that flows into the refrigerator when the door is opened (especially information on the moisture content) by recording the outside temperature / humidity information when the door is opened.

[0053] The notification control unit 175 controls the input / output device 8 to perform notification. For example, the notification control unit 175 determines whether or not frost formation on the rotor blades 92 occurs more frequently than a predetermined condition based on the frost formation information. Specifically, the notification control unit 175 determines whether or not frost formation on the rotor blades 92 occurs more than a predetermined number of times within a predetermined time period. If it is determined that frost is forming on the rotor 92 more frequently than a specified condition, i.e., if it is determined that frost has formed on the rotor 92 more than a specified number of times within a specified time period, the notification control unit 175 notifies the input / output device 8 that frost is forming frequently on the rotor 92.

[0054] In this case, the input / output device 8 corresponds to an example of a frost formation notification unit. The input / output device 8 may notify the user by displaying or outputting a message indicating that frost formation on the rotor blades 92 is occurring frequently, or by both of them. A user who receives the notification can understand that frost is occurring frequently and can take measures, such as reducing the number of times the door is opened.

[0055] The notification control unit 175 may cause the wireless communication unit 19 to notify the user of frequent frost formation on the rotor blades 92 in addition to or instead of the input / output device 8. In this case, the wireless communication unit 19 corresponds to an example of a frost formation notification unit. For example, wireless communication unit 19 may transmit information indicating that frost frequently forms on rotor 92 to a server device installed in an office where maintenance of refrigerator 100 is performed, or to a smartphone carried by a maintenance worker, or to both of them. The maintenance worker who receives the notification can understand that frost frequently forms, and can take measures such as suggesting to the user to perform an inspection.

[0056] In addition, when the notification control unit 175 determines that there is frost on the rotor 92 and determines, based on the door opening / closing information, that at least either the number of times the door was opened or the time the door was open is greater or longer than a predetermined condition, it causes the input / output device 8 to be notified of the possibility of frost forming due to opening the door.

[0057] For example, when the frost determination unit 172 determines that frost has formed on the rotor 92, the notification control unit 175 reads the door opening / closing information from the storage unit 20, counts the number of times the door has been opened, and calculates the time the door has been open. Then, the notification control unit 175 determines whether the number of times the door has been opened is greater than or equal to a predetermined condition, and whether the time the door has been open is greater than or equal to a predetermined condition. When it is determined that at least either the number of times the door has been opened is greater than or equal to the predetermined condition, or the time the door has been open is greater than or equal to the predetermined condition, the notification control unit 175 causes the input / output device 8 to notify that frost may have formed as a result of the user opening the door.

[0058] In this case, the combination of the notification control unit 175 and the input / output device 8 corresponds to an example of a frost formation cause notification unit. The input / output device 8 may notify by displaying or outputting a voice message indicating that frost may occur when the user opens the door, or by both. A user who receives the notification can understand that frost may be occurring when the door is opened, and can take measures such as reducing the number of times the door is opened.

[0059] The notification control unit 175 may cause the wireless communication unit 19 to notify the possibility of frost formation due to opening of the door in addition to or instead of the input / output device 8. In this case, the combination of the notification control unit 175 and the wireless communication unit 19 corresponds to an example of a frost formation cause notification unit. For example, wireless communication unit 19 may transmit information indicating that frost may be caused by the user opening the door to a server device installed in an office where maintenance of refrigerator 100 is performed, or to a smartphone carried by a maintenance worker, or to both of them. The maintenance worker who receives the notification can understand that frost may be caused by the user opening the door, and can take measures such as suggesting to the user how to use refrigerator 100 in a way that reduces the number of times the door is opened.

[0060] Here, the number of times the doors are opened may be greater than or equal to a predetermined condition, but is not limited to this, and the total number of times each door is opened for all doors is greater than or equal to a predetermined threshold. The duration that a door is open may be greater than or equal to a predetermined condition, but is not limited to this, and the total duration that each door is open for all doors is greater than or equal to a predetermined threshold.

[0061] When it is determined that frost has formed on the rotor 92, the notification control unit 175 may determine the possibility of frost forming due to opening the door based on the outside air temperature and humidity information at the time the door is opened and closed, in addition to or instead of the door opening / closing information. For example, the notification control unit 175 applies the outside air temperature and humidity to a predetermined moisture content calculation formula to calculate an estimated moisture content contained in the air that will flow into the interior (storage chamber) when the door is opened. Then, the notification control unit 175 determines whether the estimated moisture content is equal to or greater than a moisture content under a predetermined condition, such as determining whether the estimated moisture content is equal to or greater than a predetermined threshold value. If it is determined that the estimated moisture content is equal to or greater than the moisture content under the specified conditions, as described above, the notification control unit 175 causes the input / output device 8 or the wireless communication unit 19, or both, to notify the user of the possibility of frost formation due to opening the door.

[0062] In addition, when it is determined that there is frost on the rotor 92 and, based on the door opening / closing information, that both the number of times the door was opened and the time the door was open are within predetermined conditions, the notification control unit 175 causes the input / output device 8 to be notified of the possibility of frost formation due to a malfunction of the refrigerator 100. For example, when the frost determination unit 172 determines that frost has formed on the rotor 92, the notification control unit 175 reads the door opening / closing information from the storage unit 20, counts the number of times the door has been opened, and calculates the time the door has been open. Then, the notification control unit 175 determines whether or not the number of times the door has been opened is equal to or less than a predetermined condition, and whether or not the time the door has been open is equal to or less than a predetermined condition. When it is determined that both the number of times the door has been opened and the time the door has been open are equal to or less than the predetermined condition, the notification control unit 175 causes the input / output device 8 to notify that frost may have formed due to a malfunction of the refrigerator 100.

[0063] In this case, the combination of the notification control unit 175 and the input / output device 8 corresponds to an example of a malfunction possibility notification unit. The input / output device 8 may perform the notification by displaying or outputting a sound or by both of a message indicating that frost may have occurred due to a malfunction of the refrigerator 100. The user who receives the notification can understand that frosting may be caused by a malfunction of the refrigerator 100, and can take measures such as requesting a repairman to repair the refrigerator.

[0064] The notification control unit 175 may cause wireless communication unit 19 to notify of the possibility of frost formation due to a malfunction of refrigerator 100 in addition to or instead of input / output device 8. In this case, the combination of notification control unit 175 and wireless communication unit 19 corresponds to an example of a malfunction possibility notification unit. For example, wireless communication unit 19 may transmit information indicating that frost may have occurred due to a malfunction of refrigerator 100 to a server device installed in an office where maintenance of refrigerator 100 is performed, or to a smartphone carried by a maintenance worker, or to both of them. The maintenance worker who receives the notification can understand that frost may have occurred due to a malfunction of refrigerator 100, and can take measures such as suggesting to the user to perform inspection and repair work.

[0065] Here, the number of times the door is opened may be equal to or less than a predetermined condition, and the total number of times each door is opened for all doors may be equal to or less than a predetermined threshold value, but is not limited to this. The duration that the door is open may be equal to or less than a predetermined condition, and the total duration that each door is open for all doors may be equal to or less than a predetermined threshold value, but is not limited to this.

[0066] When it is determined that frost has formed on rotor 92, notification control unit 175 may determine the possibility of frost formation due to a malfunction of refrigerator 100 based on outside air temperature and humidity information at the time of opening and closing of the door in addition to or instead of the door opening / closing information. For example, as described above, the notification control unit 175 applies the outside air temperature and the outside air humidity to a predetermined moisture content calculation formula to calculate an estimated moisture content contained in the air that flows into the interior (storage chamber) when the door is opened. Then, the notification control unit 175 determines whether the estimated moisture content is equal to or less than a moisture content of a predetermined condition, such as determining whether the estimated moisture content is equal to or less than a predetermined threshold value. The predetermined condition for determining the possibility of frost formation due to a malfunction of the refrigerator 100 may be the same as or different from the predetermined condition for determining the possibility of frost formation due to opening the door, as described above. When it is determined that the estimated moisture content is equal to or less than the moisture content of the predetermined condition, as described above, the notification control unit 175 causes the input / output device 8 or the wireless communication unit 19, or both, to notify of the possibility of frost formation due to a malfunction of the refrigerator 100.

[0067] The notification control unit 175 may determine whether the number of times the door is opened is equal to or less than the predetermined condition by determining whether the number of times the door is opened is greater than or equal to the predetermined condition, as described above. In this case, the notification control unit 175 may determine that the number of times the door is opened is equal to or less than the predetermined condition by determining that the number of times the door is opened is not greater than or equal to the predetermined condition, that is, that the number of times the door is opened is less than the predetermined condition.

[0068] The notification control unit 175 may also determine whether the time the door was open is equal to or less than the predetermined condition by determining whether the time the door was open is longer than the predetermined condition, as described above. In this case, the notification control unit 175 may determine that the time the door was open is equal to or less than the predetermined condition by determining that the time the door was open is not longer than the predetermined condition, that is, that the time the door was open is less than the predetermined condition.

[0069] In order to determine whether the blower 9 is operating stably (normality of feedback control), an upper threshold and a lower threshold are set for the rotation speed of the rotor 92, based on the target rotation speed Ncom per unit time. The operation control unit 171 can detect an operational abnormality of the blower 9 by monitoring whether the operation of the blower 9 at a rotation speed outside the threshold continues for a certain period of time or more.

[0070] The threshold changing unit 176 variably sets the lower limit threshold of the rotation speed of the rotor 92. In particular, when it is determined that there is frost on the rotor 92, the threshold changing unit 176 changes the lower limit threshold of the rotation speed of the rotor 92 to a value smaller than the lower limit threshold when it is determined that there is no frost on the rotor 92. This lower limit threshold of the rotation speed of the rotor 92 is used to determine whether an abnormality has occurred in the rotation speed of the rotor 92.

[0071] Fig. 8 is a graph showing an example of changing the lower limit threshold of the rotation speed of the rotor 92 by the threshold changing unit 176. The horizontal axis of the graph in Fig. 8 represents time, and the vertical axis represents the rotation speed of the DC motor 91. In Fig. 8, the rotation speed of the DC motor 91 is represented by the number of square waves per unit time in the FG signal.

[0072] A line L21 indicates the rotation speed of the DC motor 91. Specifically, the line L21 indicates Nret in Fig. 5. A line L22 indicates an upper threshold of the rotation speed of the DC motor 91. A line L23 indicates a lower threshold of the rotation speed of the DC motor 91. 8, the frost determination unit 172 determines at time T1 that frost has formed on the rotor blades 92. Before time T1, the threshold value change unit 176 sets the upper threshold value indicated by line L22 to Nu and sets the lower threshold value indicated by line L23 to Nl1.

[0073] 8, the threshold change unit 176 sets the upper limit threshold and the lower limit threshold such that the margin from Ncom, which is the target value of the rotation speed during normal operation, is the same value E for both the upper limit threshold and the lower limit threshold. That is, Nu-Ncom=E, Ncom-Nl1=E. However, the threshold change unit 176 may set the upper limit threshold and the lower limit threshold such that the magnitude of the margin from Ncom differs between the upper limit threshold and the lower limit threshold.

[0074] When the frost determination unit 172 determines that frost has formed on the rotor blades 92, the threshold change unit 176 changes the lower limit threshold indicated by the line L23 to Nl2, which is smaller than Nl1. In this case, the size of the margin from Ncom is represented as P. That is, Ncom-Nl2=P. After time T1, at time T2, the rotation speed of the DC motor 91 indicated by line L21 starts to decrease from Ncom due to frost on the rotor blades 92. In the example of Fig. 8, the rotation speed of the DC motor 91 decreases at a constant rate of change, and reaches the lower limit threshold value Nl2 at time T3.

[0075] The value of Nl2 can be set to various values ​​that are smaller than Nl1 and are equal to or greater than the rated minimum rotation speed of the DC motor 91. For example, the value of P may be set to four times the value of E. Alternatively, the value of N12 may indicate the rated minimum rotation speed of the DC motor 91.

[0076] The operation control unit 171 may change the process to be performed when the rotation speed of the DC motor 91 reaches the lower limit threshold depending on whether frost formation on the rotor blades 92 is detected. When the frost determination unit 172 does not detect frost on the rotor blades 92 and the operation control unit 171 detects that the rotation speed of the DC motor 91 is equal to or lower than a lower limit threshold, the operation control unit 171 may stop or restart the DC motor 91. Restarting the DC motor 91 may eliminate or reduce the abnormality, and may reduce the error between the target value and the measured value of the rotation speed. In addition, when the abnormality is not eliminated by restarting the DC motor 91, it may be possible to stop the DC motor 91 and wait for maintenance such as repair.

[0077] On the other hand, if frost has formed on the rotor 92, the frost will not be removed even if the rotor 92 is stopped for restart. Conversely, the amount of frost may increase when the rotor 92 is stopped. Therefore, when the frost determination unit 172 detects frost on the rotor 92 and the operation control unit 171 detects that the rotation speed of the DC motor 91 has fallen below a lower threshold value, the operation control unit 171 may perform a defrosting process on the rotor 92 without restarting the rotor 92.

[0078] In the defrosting process, the operation control unit 171 controls the defrost heater 18 to heat the defrost heater 18 itself. This heats the air around the defrost heater 18. The heated air reaches the blower 9 and melts the frost adhering to the rotor 92. Note that in the defrosting process, the operation control unit 171 stops the blower 9 in order to reduce as much as possible the temperature rise in the storage compartment caused by the air heated by the defrost heater 18 flowing into the storage compartment.

[0079] In preparation for a rise in temperature inside the storage compartment during defrosting, the operation control unit 171 may perform pre-cooling of the storage compartment before the defrosting process is performed. In pre-cooling, the operation control unit 171 controls the blower 9 to increase the rotation speed of the rotor 92. This increases the amount of cool air flowing into the storage compartment by the cooler 15, and the storage compartment is cooled.

[0080] For example, when the frost determination unit 172 determines that frost has formed on the rotor blades 92, the operation control unit 171 starts pre-cooling of the storage compartment prior to defrosting of the rotor blades 92. After a predetermined time has elapsed, the operation control unit 171 ends the pre-cooling and performs the defrosting process. Here, even during the execution of pre-cooling, the amount of frost adhering to the rotor 92 may increase, causing a decrease in the rotation speed of the rotor 92. If the rotation speed of the rotor 92 decreases and a rotation speed required for pre-cooling cannot be obtained, it is possible to terminate or shorten the pre-cooling and perform a defrosting process on the rotor 92. Therefore, when the operation control unit 171 determines that the measured value of the rotation speed of the rotor 92 has fallen to a lower limit threshold value or lower during the execution of pre-cooling, it terminates or shortens the pre-cooling and performs a defrosting process on the rotor 92.

[0081] Alternatively, the operation control unit 171 may perform the defrosting process without performing pre-cooling. In this case, even after it is determined that there is frost on the rotor blades 92, the operation control unit 171 may continue the same cooling control as before it is determined that there is frost on the rotor blades 92, and then perform the defrosting process. Continuing the same cooling control here may mean that the target value of the rotation speed of the rotor 92 remains the same. By continuing the same cooling control as before it is determined that frost has formed on the rotor 92 before the operation control unit 171 starts the defrosting process, it is possible to stabilize the temperature inside the storage compartment, for example by returning the temperature inside the storage compartment to the temperature before the door was opened when the door is opened and the temperature inside the storage compartment temporarily rises.

[0082] For example, when it is determined that there is frost on the rotor 92, the operation control unit 171 continues the same cooling control as before it was determined that there is frost on the rotor 92. Thereafter, when it is determined that the measured rotation speed has fallen to a value equal to or lower than the lower limit threshold value of the rotation speed, the operation control unit 171 performs a defrosting process on the rotor 92.

[0083] Alternatively, when the operation control unit 171 determines that frost has formed on the rotor 92, it may combine the continuation of the same cooling control as before it was determined that frost has formed on the rotor 92 with pre-cooling the storage chamber. For example, when it is determined that there is frost on the rotor 92, the operation control unit 171 continues the same cooling control as before it was determined that there is frost on the rotor 92. Thereafter, when the operation control unit 171 determines that the measured value of the rotation speed has fallen to a pre-cooling threshold or lower, it starts pre-cooling the storage compartment prior to the defrosting process of the rotor 92. When a predetermined time has elapsed, the operation control unit 171 ends the pre-cooling and performs the defrosting process. Alternatively, when the operation control unit 171 determines that the measured value of the rotation speed of the rotor 92 has fallen to a lower limit threshold of the rotation speed during the execution of pre-cooling, it ends or shortens the pre-cooling and performs the defrosting process of the rotor 92.

[0084] 9 and 10 are flowcharts showing an example of a processing procedure in which control unit 17 controls the operation of blower 9. Control unit 17 repeatedly executes the processing shown in Figs. 9 and 10 periodically, for example, every second. 9 and 10, the operation control unit 171 acquires the value of Ncom (step S101). As described above, Ncom indicates the target value of the rotation speed of the DC motor 91.

[0085] Next, the operation control unit 171 judges whether or not the value of Ncom is 0 (step S102). The value of Ncom being 0 indicates that the DC motor 91 is to be stopped. When it is determined that the value of Ncom is 0 (step S102: YES), the operation control unit 171 sets the value of FLG_retry to 0 (step S141). The value of FLG_retry being 1 indicates that the fan 9 is to be restarted. The value of FLG_retry being 0 indicates that the fan 9 is not to be restarted.

[0086] Next, the operation control unit 171 sets the value of CNT_stop to 0 (step S142). CNT_stop is a variable that counts the waiting time when the blower 9 is restarted. Next, the operation control unit 171 sets the value of CNT_retry to 0 (step S161). CNT_retry is a variable that counts the duration of the abnormal state of the rotation speed in order to determine whether or not to restart the blower 9.

[0087] Next, the operation control unit 171 sets the value of DUTY_next to 0 (step S162). In the process shown in Figs. 9 and 10, DUTY_now and DUTY_next are used as variables indicating the duty ratio in the PWM signal for the blower 9. DUTY_now indicates the current setting value of the duty ratio. DUTY_next indicates the next setting value of the duty ratio. Setting the duty ratio to 0 is equivalent to instructing the DC motor 91 to stop.

[0088] Next, the operation control unit 171 sets the value of DUTY_now to the value of DUTY_next (step S163). That is, the operation control unit 171 substitutes the value of DUTY_next for DUTY_now. Next, the operation control unit 171 outputs a PWM signal having a duty ratio indicated by DUTY_now to the blower 9 (step S164).

[0089] Next, the operation control unit 171 increments the value of CNT_loop by 1 (step S165). CNT_loop is a variable that counts the number of times the processes shown in Fig. 9 and Fig. 10 are executed. CNT_loop is used to determine whether or not frost has formed on the rotor blades 92 every time the processes shown in Fig. 9 and Fig. 10 are repeated a predetermined number of times.

[0090] Next, the operation control unit 171 determines whether the value of CNT_loop is 60 or not (step S166). If the operation control unit 171 determines that the value of CNT_loop is not 60 (step S166: NO), the control unit 17 ends the processing shown in FIG. 9 and FIG. 10.

[0091] On the other hand, when the operation control unit 171 determines that the value of CNT_loop is 60 (step S166: YES), the frost formation determination unit 172 determines whether or not frost has formed on the rotor blades 92 (step S171). In addition, the operation control unit 171 sets the value of CNT_loop to 0 (step S172). After step S172, the control unit 17 ends the process shown in FIGS.

[0092] On the other hand, if it is determined in step S102 that the value of Ncom is not 0 (step S102: NO), the operation control unit 171 determines whether the value of FLG_defrost_propeller is 1 or 0 (step S111). A value of FLG_defrost_propeller of 1 indicates that defrost processing of the rotor blades 92 is performed. A value of FLG_defrost_propeller of 0 indicates that defrost processing of the rotor blades 92 is not performed.

[0093] When the operation control unit 171 determines that the value of FLG_defrost_propeller is 1 (step S111: YES), the process proceeds to step S141. On the other hand, if the operation control unit 171 determines that the value of FLG_defrost_propeller is 0 (step S111: NO), the operation control unit 171 determines whether the value of FLG_retry is 1 or 0 (step S121).

[0094] When it is determined that the value of FLG_retry is 1 (step S121: YES), the operation control unit 171 determines whether the value of CNT_stop is smaller than the value of TM_stop (step S131). TM_stop indicates an upper threshold value of the value of CNT_stop. When restarting the blower 9, the operation control unit 171 sets the duty ratio to 0 to instruct the blower to stop, and then, after TM_stop seconds have elapsed, operates the blower 9 with a duty ratio according to Ncom.

[0095] When it is determined that the value of CNT_stop is smaller than the value of TM_stop (step S131: YES), the operation control unit 171 increments the value of CNT_stop by 1 (step S151). After step S151, the process proceeds to step S161. On the other hand, in step S131, if the operation control unit 171 determines that the value of CNT_stop is equal to or greater than the value of TM_stop (step S131: NO), the process proceeds to step S141.

[0096] On the other hand, when it is determined in step S121 that the value of FLG_retry is 0 (step S121: NO), the operation control unit 171 acquires the value of Nret (step S201). As described above, the value of Nret indicates the measured value of the rotation speed of the DC motor 91. Next, the subtractor 272 of the operation control unit 171 sets the value of diff to the difference obtained by subtracting the value of Nret from the value of Ncom. diff corresponds to ΔN in FIG.

[0097] Next, the operation control unit 171 determines whether the value of diff is greater than −E (step S203). Here, E is the same as E shown in Fig. 8. The value of diff being greater than −E is equivalent to Nret being smaller than the threshold value Nu shown in Fig. 8.

[0098] When it is determined that the value of diff is greater than -E (step S203: YES), the operation control unit 171 determines whether the value of FLG_Propeller is 0 or 1 (step S211). The value of FLG_Propeller being 1 indicates a determination result that frost has formed on the rotor blades 92. The value of FLG_Propeller being 0 indicates a determination result that frost has not formed on the rotor blades 92.

[0099] When it is determined that the value of FLG_Propeller is 0 (step S211: YES), the operation control unit 171 determines whether or not the value of diff is smaller than E (step S221). The value of diff being smaller than E is equivalent to the value of Nret being larger than the threshold value Nl1 shown in FIG.

[0100] When it is determined that the value of diff is smaller than E (step S221: YES), the operation control unit 171 sets the value of CNT_retry to 0 (step S251). Next, the operation control unit 171 performs a process of updating the control command value (step S271). After step S271, the process proceeds to step S163.

[0101] On the other hand, when it is determined in step S203 that the value of diff is equal to or less than −E (step S203: NO), the operation control unit 171 increments the value of CNT_retry by 1 (step S231). Then, the operation control unit 171 determines whether or not the value of CNT_retry is smaller than the value of TM_retry (step S232). TM_retry constitutes part of the determination condition for whether or not to restart the blower 9. The operation control unit 171 restarts the blower 9 when a state in which the value of diff does not fall within ±E continues for TM_retry seconds.

[0102] When it is determined that the value of CNT_retry is smaller than the value of TM_retry (step S232: YES), the operation control unit 171 sets the value of FLG_retry to 1 (step S241). In addition, the operation control unit 171 sets the value of CNT_stop to 0 (step S242). After step S242, the process proceeds to step S162.

[0103] On the other hand, in step S221, when the driving control unit 171 determines that the value of diff is equal to or greater than the value of E (step S221: NO), the process proceeds to step S231. In step S232, if it is determined that the value of CNT_retry is equal to or greater than the value of TM_retry (step S232: NO), the process proceeds to step S237.

[0104] When it is determined in step S211 that the value of FLG_propeller is 1 (step S211: NO), the operation control unit 171 determines whether or not the value of diff is smaller than P (step S261). Here, P is the same as P shown in Fig. 8. The value of diff being smaller than P is equivalent to Nret being larger than the threshold value Nl2 shown in Fig. 8.

[0105] When the driving control unit 171 determines that the value of diff is smaller than the value of P (step S261: YES), the process proceeds to step S271. On the other hand, if it is determined that the value of diff is equal to or greater than the value of P (step S261: NO), the operation control unit 171 sets the value of FLG_defrost_propeller to 1 (step S281). That is, the operation control unit 171 decides to perform the defrosting process on the rotor blades 92. Furthermore, the operation control unit 171 sets the value of DUTY_next to 0 (step S282) in order to stop the blower 9 during the defrosting process. After step S282, the process proceeds to step S163.

[0106] 11 is a flowchart showing an example of a processing procedure for updating a control command value by the control unit 17. In step S271 of FIG. In the process shown in Fig. 11, the operation control unit 171 judges whether the value of diff is greater than the value of -F0 and smaller than the value of F0 (step S301). F0 indicates a first threshold for evaluating the magnitude (absolute value) of the value of diff. When the magnitude of the value of diff is large, the operation control unit 171 evaluates the magnitude of the value of diff in order to control Nret to approach Ncom by greatly changing the duty ratio.

[0107] When it is determined that the value of diff is greater than the value of -F0 and smaller than the value of F0 (step S301: YES), the operation control unit 171 sets the value of DUTY_delta to a value obtained by multiplying the value of diff by the value of K0 (step S321). The value of DUTY_delta indicates the amount of change in the duty ratio. K0 is a positive real coefficient that is multiplied by the value of diff according to the evaluation result of the magnitude of the value of diff.

[0108] Next, the operation control unit 171 sets the value of DUTY_next to a value obtained by adding the value of DUTY_delta to the value of DUTY_now (step S331). As a result, the operation control unit 171 updates the rectangular width (duty ratio) of the PWM signal so that the value of the difference diff between the value of Ncom and the value of Nret approaches 0. Next, the operation control unit 171 determines whether the value of DUTY_next is greater than the value of DUTY_MAX (step S341). DUTY_MAX indicates the maximum value that the duty ratio can take. For example, in the case of FIG. 6, the value of DUTY_MAX is set to 100%.

[0109] When it is determined that the value of DUTY_next is greater than the value of DUTY_MAX (step S341: YES), the operation control unit 171 sets the value of DUTY_next to the value of DUTY_MAX (step S361). That is, the operation control unit 171 substitutes the value of DUTY_MAX for DUTY_next. After step S361, the control unit 17 ends the process shown in FIG.

[0110] On the other hand, when it is determined in step S341 that the value of DUTY_next is equal to or less than the value of DUTY_MAX (step S341: NO), the operation control unit 171 determines whether the value of DUTY_next is smaller than the value of DUTY_MIN (step S351). DUTY_MIN indicates the minimum value that the duty ratio can take. For example, in the case of FIG. 6, the value of DUTY_MIN is set to 35% at which the rotation speed of the DC motor 91 becomes the rated minimum rotation speed.

[0111] When it is determined that the value of DUTY_next is smaller than the value of DUTY_MIN (step S351: YES), the operation control unit 171 sets the value of DUTY_next to the value of DUTY_MIN (step S371). That is, the operation control unit 171 substitutes the value of DUTY_MIN for DUTY_next. After step S371, the control unit 17 ends the process shown in FIG. On the other hand, if the operation control unit 171 determines that the value of DUTY_next is equal to or greater than the value of DUTY_MIN (step S351: YES), the control unit 17 ends the process shown in FIG.

[0112] 12 is a flowchart showing an example of a processing procedure in which the frost formation determining unit 172 determines the presence or absence of frost on the rotor blades 92. The frost formation determining unit 172 performs the processing shown in FIG. 12, the frost formation determination unit 172 determines whether the value of Ncom is equal to or greater than 1 (step S401). When the value of Ncom is equal to or greater than 1, it indicates that an instruction is issued to operate the DC motor 91.

[0113] When it is determined that the value of Ncom is equal to or greater than 1 (step S401: YES), the frost formation determining unit 172 determines whether the value of Ncom is equal to the value of Ncom_old (step S402). Ncom_old indicates the previous value of Ncom. When it is determined that the value of Ncom is equal to the value of Ncom_old (step S402: YES), the frost formation determining unit 172 determines whether the value of DUTY_old is less than the value of DUTY_now (step S403). DUTY_old indicates the previous duty ratio.

[0114] When it is determined that the value of DUTY_old is less than the value of DUTY_now (step S403: YES), the frost formation determining unit 172 determines whether the value of Nret_old-Nret is equal to or greater than -1 and equal to or less than 1 (step S404). Nret_old indicates the previous value of Nret.

[0115] When it is determined that the value of Nret_old-Nret is equal to or greater than -1 and equal to or less than 1 (step S404: YES), the frost formation determination unit 172 increments the value of CNT_propeller by 1 (step S421). CNT_propeller is a variable that counts the number of times that the conditions determined in steps S401 to S413 are satisfied consecutively.

[0116] Next, the frost determination unit 172 determines whether the value of CNT_propeller is equal to or greater than the value of TM_propeller (step S422). TM_propeller indicates the number of times that the conditions determined in steps S401 to S413 must be satisfied in succession in order to determine that frost has formed on the rotor blades 92.

[0117] When it is determined that the value of CNT_propeller is equal to or greater than the value of TM_propeller (step S422: YES), the frost determination unit 172 sets the value of FLG_Propeller to 1 (step S431). The value of FLG_Propeller being 1 indicates a determination result that frost has formed on the rotor blades 92.

[0118] Next, the frost formation determination unit 172 sets the value of DUTY_now to the value of DUTY_old (Step S451). That is, the frost formation determination unit 172 substitutes the value of DUTY_now for DUTY_old. Moreover, the frost formation determination unit 172 sets the value of Nret_now to the value of Nret_old (Step S452). That is, the frost formation determination unit 172 substitutes the value of Nret_now for Nret_old. Then, the frost formation determination unit 172 sets the value of Ncom to the value of Ncom_old (step S453). That is, the frost formation determination unit 172 substitutes the value of Ncom for Ncom_old. After step S453, the frost formation determining unit 172 ends the process shown in FIG.

[0119] On the other hand, when it is determined in step S401 that the value of Ncom is smaller than 1 (step S401: NO), the frost formation determining unit 172 sets the value of CNT_propeller to 0 (step S441). After step S441, the process proceeds to step S451. Also in step S402, if the frost formation determining unit 172 determines that the value of Ncom is different from the value of Ncom_old (step S402: NO), the process proceeds to step S441.

[0120] On the other hand, when it is determined in step S403 that the value of DUTY_old is equal to or greater than the value of DUTY_now (step S403: NO), the frost formation determining unit 172 determines whether the value of DUTY_old is equal to the value of DUTY_MAX (step S411). When it is determined that the value of DUTY_old is equal to the value of DUTY_MAX (step S411: YES), the frost formation determining unit 172 determines whether the value of DUTY_now is equal to the value of DUTY_MAX (step S412).

[0121] When it is determined that the value of DUTY_now is equal to the value of DUTY_MAX (step S412: YES), the frost formation determining unit 172 determines whether the value of Nret_old is greater than the value of Nret (step S413). When the frost formation determining unit 172 determines that the value of Nret_old is larger than the value of Nret (step S413: YES), the process proceeds to step S421.

[0122] On the other hand, in step S411, if the frost formation determining unit 172 determines that the value of DUTY_old is different from the value of DUTY_MAX (step S411: NO), the process proceeds to step S441. If the frost formation determining unit 172 determines in step S412 that the value of DUTY_now is different from the value of DUTY_MAX (step S412: NO), the process also proceeds to step S441.

[0123] If the frost formation determining unit 172 determines in step S413 that the value of Nret_old is equal to or less than the value of Nret (step S413: NO), the process also proceeds to step S441. On the other hand, in step S404, if the frost formation determining unit 172 determines that the value of Nret_old-Nret is outside the range from -1 to 1 (step S404: NO), the process proceeds to step S411.

[0124] As described above, the housing 1 includes a storage chamber. The cooler 15 is provided in the housing 1. The blower 9 blows cool air to be cooled by the cooler 15. The frost determination unit 172 determines the presence or absence of frost on the rotor 92 based on the continuation of a state in which at least one of the following is detected: a target value of the rotation speed of the rotor 92 of the blower 9 is constant, while a control signal of feedback control for the blower 9 indicates an increase in the rotation speed of the rotor 92, or a control signal indicates constant speed rotation of the rotor 92, while a measured value of the rotation speed of the rotor 92 is decreasing. The operation control unit 171 performs a defrosting process on the rotor 92 when predetermined conditions including a determination that frost is present on the rotor 92 are satisfied.

[0125] According to refrigerator 100, frost formation determination unit 172 can detect frost formation on rotor 92 by distinguishing it from an abnormality in the rotation speed of rotor 92 caused by a malfunction of blower 9. When frost formation determination unit 172 detects frost formation on rotor 92, operation control unit 171 can perform a defrosting process on rotor 92.

[0126] Here, as one of the countermeasures when an abnormality occurs in the rotation speed of the rotor blades of the blower of the refrigerator, it is considered to restart the blower. However, when frost has formed on the rotor blades, restarting the blower usually does not improve the frost condition. Furthermore, by temporarily stopping the rotation of the rotor blades in order to restart the blower, the amount of frost that adheres to the rotor blades may increase. In response to this, in refrigerator 100, frost on rotor 92 is detected separately from an abnormality in the rotation speed of rotor 92 caused by a failure of blower 9, and thus defrosting process can be performed on rotor 92. It is expected that the abnormality in the rotation speed of rotor 92 will be resolved by the defrosting process.

[0127] Furthermore, when it is determined that frost has formed on the rotor 92, the frost information recording unit 173 records frost information indicating frost formation on the rotor 92. When it is determined based on the frost information that frost formation on the rotor 92 occurs more frequently than a predetermined condition, the frost notification unit notifies that frost formation on the rotor 92 occurs frequently.

[0128] When a user receives the notification, the user can understand that frost formation occurs frequently and can take measures such as reducing the number of times the door is opened. Alternatively, when a maintenance worker receives the notification, the maintenance worker can understand that frost formation occurs frequently and can take measures such as suggesting to the user that an inspection be performed.

[0129] The door of the storage compartment is closed so that the storage compartment can be opened and closed. The door opening / closing detection unit detects whether the door is open or closed. The door opening / closing information recording unit 174 records door opening / closing information indicating the door opening / closing status based on the detection result of the door opening / closing detection unit. The frost formation cause notification unit notifies the possibility of frost formation due to opening of the door when it is determined that there is frost on the rotor blade and, based on the door opening / closing information, it is determined that at least one of the number of times the door is opened or the time the door is open is greater than or longer than a predetermined condition. In addition to or instead of the door opening / closing information, it is also possible to notify the possibility of frost formation due to opening the door based on the outside temperature and humidity information at the time the door is opened or closed.

[0130] When a user receives the notification, the user can understand that frost may be caused by opening the door, and can take measures such as reducing the number of times the door is opened. Alternatively, when a maintenance worker receives the notification, the maintenance worker can understand that frost may be caused by the user opening the door, and can take measures such as suggesting to the user how to use refrigerator 100 in a way that reduces the number of times the door is opened.

[0131] Further, the door of the storage compartment closes to allow the storage compartment to be opened and closed. The door opening / closing detection unit detects whether the door is opened or closed. The door opening / closing information recording unit 174 records the door opening / closing information indicating the opening / closing status of the door based on a detection result of the door opening / closing detection unit. When it is determined that there is frost on the rotor 92 and based on the door opening / closing information that both the number of times the door is opened and the time the door is open are equal to or less than predetermined conditions, the malfunction possibility notification unit notifies of the possibility of frost formation due to a malfunction of the refrigerator. In addition to or instead of the door opening / closing information, it is also possible to notify the possibility of frost formation due to a malfunction of the refrigerator 100 based on the outside air temperature and humidity information at the time the door is opened or closed.

[0132] When the user receives the notification, the user can understand that frost may be occurring due to a malfunction of the refrigerator 100, and can take measures such as requesting a repair service. When a maintenance worker receives the notification, the maintenance worker can understand that frost may be occurring due to a malfunction of refrigerator 100, and can take measures such as suggesting to the user to perform inspection and repair work.

[0133] Furthermore, the threshold change unit 176 sets a variably lower limit threshold for the rotation speed of the rotor 92. When the operation control unit 171 determines that the measured value of the rotation speed is equal to or lower than the lower limit threshold for the rotation speed, it performs processing for when an abnormality in the rotation speed occurs. When it is determined that there is frost on the rotor 92, the threshold change unit 176 changes the lower limit threshold for the rotation speed to a value smaller than the lower limit threshold for the rotation speed when it is determined that there is no frost on the rotor 92. This allows the operation control unit 171 to continue the same cooling control for a relatively long period of time before starting the defrosting process, as was done before it was determined that frost had formed on the rotor blades, thereby stabilizing the temperature inside the storage chamber.

[0134] In addition, if it is determined that there is no frost on the rotor 92, the operation control unit 171 stops or restarts the blower 9 as a process to be taken when an abnormality occurs in the rotation speed of the rotor 92, and if it is determined that there is frost on the rotor 92, the operation control unit 171 performs a defrost process on the rotor 92 as a process to be taken when an abnormality occurs in the rotation speed of the rotor 92. As a result, in refrigerator 100, when frost forms on rotor 92, rotor 92 can be temporarily stopped for restart to prevent the amount of frost from increasing, and it is expected that rotor 92 can be defrosted in a relatively short time.

[0135] In addition, if the operation control unit 171 determines that frost has formed on the rotor 92, it continues the same cooling control as before it determined that frost has formed on the rotor 92, and then, if it determines that the measured rotation speed of the rotor 92 has fallen below the lower limit threshold of the rotation speed, it performs a defrosting process on the rotor 92. The operation control unit 171 continues the same cooling control as before it was determined that there was frost on the rotor blades 92, thereby stabilizing the temperature inside the storage chamber. Furthermore, according to the operation control unit 171, when it becomes impossible to ensure the rotation speed of the rotor 92 required to keep the interior of the storage compartment cooled, it is possible to transition to a defrosting process.

[0136] In addition, when the operation control unit 171 determines that frost has formed on the rotor 92, it starts pre-cooling the storage chamber prior to the defrosting process of the rotor 92, and when it determines that the measured rotation speed has fallen below the lower threshold value of the rotation speed during pre-cooling, it ends or shortens the pre-cooling and performs the defrosting process of the rotor. The operation control unit 171 pre-cools the storage compartment, thereby reducing the effect of a temperature rise in the storage compartment during defrosting. Furthermore, the operation control unit 171 can transition to defrosting when the rotation speed of the rotor 92 required to continue pre-cooling cannot be ensured.

[0137] Furthermore, when the operation control unit 171 determines that frost has formed on the rotor 92, it continues the same control as before it determined that frost has formed on the rotor 92. If it then determines that the measured rotation speed has fallen below a certain pre-cooling threshold, it starts pre-cooling for the storage chamber prior to the defrosting process of the rotor 92. If it then determines that the measured rotation speed of the rotor 92 has fallen below a lower threshold for the rotation speed during pre-cooling, it terminates or shortens the pre-cooling and performs the defrosting process of the rotor. The operation control unit 171 can stabilize the temperature inside the storage compartment by continuing the same control as before it was determined that there was frost on the rotor 92. Furthermore, the operation control unit 171 can reduce the influence of a temperature rise inside the storage compartment during defrosting processing by pre-cooling the storage compartment. Furthermore, the operation control unit 171 can transition to defrosting processing when it becomes impossible to ensure the rotation speed of the rotor 92 required to continue pre-cooling.

[0138] Furthermore, the outdoor air temperature measuring unit 12 is provided outside the housing 1 and measures the outdoor air temperature. The humidity measuring unit 13 is provided outside the housing 1 and measures the outdoor air humidity. The door of the storage compartment is closed so that the storage compartment can be opened and closed. The outdoor air temperature and humidity information recording unit 177 records outdoor air temperature and humidity information indicating the outdoor air temperature and the outdoor air humidity when the door is opened and closed. When the frost formation cause notifying unit (e.g., the notifying control unit 175 and the input / output device 8) determines that frost has formed on the rotor 92 and determines based on the outdoor air temperature and humidity information that the estimated moisture amount flowing into the storage compartment is equal to or greater than the moisture amount under a predetermined condition, it notifies the possibility of frost formation by opening the door.

[0139] When a user receives the notification, the user can understand that frost may be caused by opening the door, and can take measures such as reducing the number of times the door is opened. Alternatively, when a maintenance worker receives the notification, the maintenance worker can understand that frost may be caused by the user opening the door, and can take measures such as suggesting to the user how to use refrigerator 100 in a way that reduces the number of times the door is opened.

[0140] Furthermore, outdoor air temperature measuring unit 12 is provided outside housing 1 and measures the outdoor air temperature. Humidity measuring unit 13 is provided outside housing 1 and measures the humidity of the outdoor air. The door of the storage compartment closes so that the storage compartment can be opened and closed. Outdoor air temperature and humidity information recording unit 177 records outdoor air temperature and humidity information indicating the outdoor air temperature and the outdoor air humidity when the door is opened and closed. When it is determined that there is frost on rotor 92 and based on the outdoor air temperature and humidity information that the estimated moisture amount flowing into the compartment is equal to or less than the moisture amount of a predetermined condition, a frost formation cause notifying unit (for example, notifying control unit 175 and input / output device 8) notifies of the possibility of frost formation due to a malfunction of refrigerator 100.

[0141] When the user receives the notification, the user can understand that frost may be occurring due to a malfunction of the refrigerator 100, and can take measures such as requesting a repair service. When a maintenance worker receives the notification, the maintenance worker can understand that frost may be occurring due to a malfunction of refrigerator 100, and can take measures such as suggesting to the user to perform inspection and repair work.

[0142] In the above embodiments, the control unit 17 and each of its components are software functional units, but they may be hardware functional units such as an LSI.

[0143] According to at least one of the embodiments described above, the frost determination unit determines whether or not frost has formed on the rotor blades based on the continuation of at least one of the following conditions: a target value for the rotation speed of the rotor blades of the blower is constant while a control signal of the feedback control for the blower instructs an increase in the rotation speed of the rotor blades, or a control signal instructs constant rotation of the rotor blades while a measured value of the rotation speed is decreasing. With this configuration, it is possible to distinguish and detect abnormalities in the rotation speed due to frost on the rotor blades from abnormalities in the rotation speed due to a blower failure, and perform defrosting processing.

[0144] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope of the invention and its equivalents described in the claims, as well as in the scope and spirit of the invention. [Explanation of symbols]

[0145] 100...refrigerator, 8...input / output device, 2b...refrigerator door opening / closing detection unit, 4b...vegetable door opening / closing detection unit, 5b...ice-making door opening / closing detection unit, 6b...small freezer door opening / closing detection unit, 7b...large freezer door opening / closing detection unit, 19...wireless communication unit, 20...storage unit, 17...control unit, 171...operation control unit, 172...frost formation determination unit, 173...frost formation information recording unit, 174...door opening / closing information recording unit, 175...notification control unit, 176...threshold value changing unit, 9...blower, 91...DC motor, 92...rotor, 18...defrost heater

Claims

1. a housing including a storage chamber; A cooler provided in the housing; and A blower that blows the cool air cooled by the cooler; a frost determination unit that determines whether or not frost has formed on the rotor blades based on a continuation state of at least one of the following conditions: a target value of the rotation speed of the rotor blades of the blower is constant while a control signal of a feedback control for the blower instructs an increase in the rotation speed of the rotor blades, or a control signal instructs constant speed rotation of the rotor blades while a measured value of the rotation speed is decreasing; An operation control unit that performs a defrosting process on the rotor blades when a predetermined condition including a determination that frost has formed on the rotor blades is satisfied; a frost information recording unit that records frost information indicating frost on the rotor blade when it is determined that frost has formed on the rotor blade; A frost notification unit that notifies the user that frost is frequently occurring on the rotor blade when it is determined based on the frost information that the number of times that frost is formed on the rotor blade within a predetermined time period exceeds a predetermined number. A refrigerator equipped with

2. A housing including a storage chamber; A cooler provided in the housing; A blower that blows the cool air cooled by the cooler; a frost determination unit that determines whether or not frost has formed on the rotor blades based on a continuation state of at least one of the following conditions: a target value of the rotation speed of the rotor blades of the blower is constant while a control signal of a feedback control for the blower instructs an increase in the rotation speed of the rotor blades, or a control signal instructs constant speed rotation of the rotor blades while a measured value of the rotation speed is decreasing; An operation control unit that performs a defrosting process on the rotor blades when a predetermined condition including a determination that frost has formed on the rotor blades is satisfied; A door for opening and closing the storage chamber; A door opening / closing detection unit that detects whether the door is opened or closed; a door opening / closing information recording unit that records door opening / closing information indicating an opening / closing state of the door based on a detection result of the door opening / closing detection unit; a frost formation cause notification unit that notifies the possibility of frost formation due to opening of the door when it is determined that there is frost formation on the rotor blade and, based on the door opening / closing information, it is determined that at least one of the number of times the door is opened or the time the door is open is greater than or longer than a predetermined condition; A refrigerator equipped with

3. A housing including a storage chamber; A cooler provided in the housing; and A blower that blows the cool air cooled by the cooler; a frost determination unit that determines whether or not frost has formed on the rotor blades based on a continuation state of at least one of the following conditions: a target value of the rotation speed of the rotor blades of the blower is constant while a control signal of a feedback control for the blower instructs an increase in the rotation speed of the rotor blades, or a control signal instructs constant speed rotation of the rotor blades while a measured value of the rotation speed is decreasing; An operation control unit that performs a defrosting process on the rotor blades when a predetermined condition including a determination that frost has formed on the rotor blades is satisfied; A door for opening and closing the storage chamber; A door opening / closing detection unit that detects whether the door is opened or closed; a door opening / closing information recording unit that records door opening / closing information indicating an opening / closing state of the door based on a detection result of the door opening / closing detection unit; a failure possibility notification unit that notifies a possibility of frost formation due to a malfunction of the refrigerator when it is determined that frost has formed on the rotor and, based on the door opening / closing information, both of the number of times the door has been opened and the time the door has been open are equal to or less than predetermined conditions; and A refrigerator equipped with

4. A housing including a storage chamber; A cooler provided in the housing; and A blower that blows the cool air cooled by the cooler; a frost determination unit that determines whether or not frost has formed on the rotor blades based on a continuation state of at least one of the following conditions: a target value of the rotation speed of the rotor blades of the blower is constant while a control signal of a feedback control for the blower instructs an increase in the rotation speed of the rotor blades, or a control signal instructs constant speed rotation of the rotor blades while a measured value of the rotation speed is decreasing; An operation control unit that performs a defrosting process on the rotor blades when a predetermined condition including a determination that frost has formed on the rotor blades is satisfied; a threshold value changing unit capable of changing a lower limit threshold value of the rotation speed; Equipped with When the operation control unit determines that the measured value of the rotation speed is equal to or lower than the lower limit threshold value of the rotation speed, the operation control unit performs a process for when an abnormality occurs in the rotation speed, The threshold change unit changes the lower limit threshold of the rotation speed to a value smaller than the lower limit threshold of the rotation speed when it is determined that frost has formed on the rotor blades, refrigerator.

5. The operation control unit is When it is determined that there is no frost on the rotor blades, as a process for handling the occurrence of an abnormality in the rotation speed, the blower is stopped or restarted; When it is determined that frost has formed on the rotor blades, a defrosting process is performed on the rotor blades as a process to be performed when an abnormality in the rotation speed occurs.

5. The refrigerator according to claim 4.

6. A housing including a storage chamber; A cooler provided in the housing; and A blower that blows the cool air cooled by the cooler; a frost determination unit that determines whether or not frost has formed on the rotor blades based on a continuation state of at least one of the following conditions: a target value of the rotation speed of the rotor blades of the blower is constant while a control signal of a feedback control for the blower instructs an increase in the rotation speed of the rotor blades, or a control signal instructs constant speed rotation of the rotor blades while a measured value of the rotation speed is decreasing; An operation control unit that performs a defrosting process on the rotor blades when a predetermined condition including a determination that frost has formed on the rotor blades is satisfied; Equipped with When it is determined that frost has formed on the rotor blades, the operation control unit continues the same cooling control as before it was determined that frost has formed on the rotor blades, and thereafter, when it is determined that the measured value of the rotation speed has decreased to or below a lower limit threshold value of the rotation speed, the operation control unit performs a defrosting process on the rotor blades. refrigerator.

7. A housing including a storage chamber; A cooler provided in the housing; and A blower that blows the cool air cooled by the cooler; a frost determination unit that determines whether or not frost has formed on the rotor blades based on a continuation state of at least one of the following conditions: a target value of the rotation speed of the rotor blades of the blower is constant while a control signal of a feedback control for the blower instructs an increase in the rotation speed of the rotor blades, or a control signal instructs constant speed rotation of the rotor blades while a measured value of the rotation speed is decreasing; An operation control unit that performs a defrosting process on the rotor blades when a predetermined condition including a determination that frost has formed on the rotor blades is satisfied; Equipped with When it is determined that frost has formed on the rotor blades, the operation control unit starts pre-cooling of the storage chamber prior to a defrosting process of the rotor blades, and when it is determined that the measured value of the rotation speed has fallen to or below a lower limit threshold value of the rotation speed during the execution of the pre-cooling, the operation control unit ends or shortens the pre-cooling and performs a defrosting process of the rotor blades. refrigerator.

8. A housing including a storage chamber; A cooler provided in the housing; and A blower that blows the cool air cooled by the cooler; a frost determination unit that determines whether or not frost has formed on the rotor blades based on a continuation state of at least one of the following conditions: a target value of the rotation speed of the rotor blades of the blower is constant while a control signal of a feedback control for the blower instructs an increase in the rotation speed of the rotor blades, or a control signal instructs constant speed rotation of the rotor blades while a measured value of the rotation speed is decreasing; An operation control unit that performs a defrosting process on the rotor blades when a predetermined condition including a determination that frost has formed on the rotor blades is satisfied; Equipped with When it is determined that frost has formed on the rotor blades, the operation control unit continues the same cooling control as before it was determined that frost has formed on the rotor blades, and when it is thereafter determined that the measured value of the rotation speed has fallen to a pre-cooling threshold or lower, it starts pre-cooling of the storage chamber prior to a defrosting process of the rotor blades, and when it is thereafter determined that the measured value of the rotation speed has fallen to a pre-cooling threshold or lower during the execution of the pre-cooling, it ends or shortens the pre-cooling and performs a defrosting process of the rotor blades. refrigerator.

9. A housing including a storage chamber; A cooler provided in the housing; and A blower that blows the cool air cooled by the cooler; a frost determination unit that determines whether or not frost has formed on the rotor blades based on a continuation state of at least one of the following conditions: a target value of the rotation speed of the rotor blades of the blower is constant while a control signal of a feedback control for the blower instructs an increase in the rotation speed of the rotor blades, or a control signal instructs constant speed rotation of the rotor blades while a measured value of the rotation speed is decreasing; An operation control unit that performs a defrosting process on the rotor blades when a predetermined condition including a determination that frost has formed on the rotor blades is satisfied; an outside air temperature measuring unit provided outside the housing and configured to measure an outside air temperature; a humidity measuring unit provided outside the housing for measuring the humidity of outside air; A door for opening and closing the storage chamber; an outside temperature and humidity information recording unit that records outside temperature and humidity information indicating the outside temperature and humidity when the door is opened and closed; a frost formation cause notification unit that notifies the possibility of frost formation due to opening of the door when it is determined that frost has formed on the rotor blade and that the estimated moisture amount flowing into the storage compartment is equal to or greater than a moisture amount under a predetermined condition based on the outside air temperature and humidity information; A refrigerator equipped with

10. A housing including a storage chamber; A cooler provided in the housing; and A blower that blows the cool air cooled by the cooler; a frost determination unit that determines whether or not frost has formed on the rotor blades based on a continuation state of at least one of the following conditions: a target value of the rotation speed of the rotor blades of the blower is constant while a control signal of a feedback control for the blower instructs an increase in the rotation speed of the rotor blades, or a control signal instructs constant speed rotation of the rotor blades while a measured value of the rotation speed is decreasing; An operation control unit that performs a defrosting process on the rotor blades when a predetermined condition including a determination that frost has formed on the rotor blades is satisfied; an outside air temperature measuring unit provided outside the housing and configured to measure an outside air temperature; a humidity measuring unit provided outside the housing for measuring the humidity of outside air; A door for opening and closing the storage chamber; an outside temperature and humidity information recording unit that records outside temperature and humidity information indicating the outside temperature and humidity when the door is opened and closed; a failure possibility notification unit that notifies a possibility of frost formation due to a failure of the refrigerator when it is determined that frost has formed on the rotor and, based on the outside air temperature and humidity information, it is determined that an estimated amount of moisture flowing into the refrigerator is equal to or less than a moisture amount under a predetermined condition. A refrigerator equipped with

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