Refrigerator

Abstract

Provided is a refrigerator in which a control unit determines whether or not a defrosting start condition is satisfied during operation of a cooling cycle; if the defrosting starting condition is met, whether a defrosting delay condition is met or not is judged; if the defrosting delay condition is not met, defrosting operation is started immediately; if the defrosting delay condition is satisfied, starting a defrosting operation at a delayed defrosting start time; the condition that the defrosting starting condition is met is the condition that the accumulated working time of the cooling cycle reaches the defrosting reference time; the energy-saving operation state or the normal operation state of the refrigerator in each unit time is stored in the memory; the control unit determines a delayed defrosting start time such that the defrosting operation is started in a section in which the energy-saving operation sections continuously exist. The defrosting operation comprises a pre-defrosting step and a defrosting step in which a defrosting heater works; the RPM of the fan in the first step and the RPM of the fan in the second step included in the pre-defrosting step are different and are both larger than the RPM of the fan in the working process of the cooling circulation.

Description

[0001] This invention is a divisional application of the following patent application: Application No.: 201911181245.8, Application Date: November 27, 2019, Invention Title: Refrigerator and Control Method Thereof Technical Field

[0002] This invention relates to refrigerators. Background Technology

[0003] A refrigerator is a household appliance that stores objects such as food at low temperatures in a storage compartment set up in a cabinet. Because the storage compartment is surrounded by insulated walls, the interior of the storage compartment can be maintained at a temperature lower than the outside temperature.

[0004] Based on the temperature range of the storage room, the storage room can be divided into a refrigeration room or a freezer room.

[0005] The refrigerator may include an evaporator for supplying cold air to the storage compartment. Air from the storage compartment flows into the space where the evaporator is located and is cooled during heat exchange with the evaporator; the cooled air is then resupplyed to the storage compartment.

[0006] At this time, when the air exchanging heat with the evaporator contains moisture, the moisture condenses on the surface of the evaporator during the heat exchange, thereby forming frost on the surface of the evaporator.

[0007] Since the frost acts as a flow resistance to air, the more frost condenses on the surface of the evaporator, the greater the flow resistance, which reduces the heat exchange efficiency of the evaporator and increases power consumption.

[0008] Therefore, the refrigerator also includes a defrosting mechanism for removing frost from the evaporator.

[0009] A method for changing the defrosting cycle is disclosed in Korean Patent Publication No. 2000-0004806, which is existing literature.

[0010] In existing literature, the cumulative operating time of the compressor and the external gas temperature are used to adjust the defrosting cycle.

[0011] However, when the defrosting cycle is determined by using only the cumulative operating time of the compressor and the external gas temperature, as in existing literature, it fails to reflect the actual amount of frost on the evaporator (hereinafter referred to as "frost amount"), making it difficult to accurately determine the actual time point when defrosting is required.

[0012] That is, the amount of frost on the evaporator varies depending on various environmental factors such as the user's refrigerator usage patterns and the level of moisture in the air. However, existing literature does not reflect these various environmental factors, and the defrosting cycle has not been determined.

[0013] Therefore, even with a small amount of frost, defrosting will begin, causing unnecessary power consumption due to defrosting. Summary of the Invention

[0014] This embodiment provides a refrigerator and its control method, which can delay the start of defrosting even when the defrosting start conditions are met, thereby preventing unnecessary power consumption increase caused by defrosting.

[0015] This embodiment provides a refrigerator and its control method, which can determine the compressor's cooling power based on the user's refrigerator usage mode after defrosting operation is completed, thereby preventing unnecessary power consumption increase during operation after defrosting.

[0016] According to one aspect of a refrigerator control method, the refrigerator includes: a compressor; an evaporator for supplying cold air to a storage compartment; a defrost heater for defrosting the evaporator; and a control unit for controlling the defrost heater. The refrigerator control method may include: a step of operating a cooling cycle to cool the storage compartment; a step of the control unit determining whether a defrost start condition is met during the cooling cycle; a step of the control unit determining whether a defrost delay condition is met when the defrost start condition is met; and a step of immediately starting defrost operation if the defrost delay condition is not met, and starting defrost operation at a delayed defrost start time if the defrost delay condition is met.

[0017] In this embodiment, when the defrosting start condition is met, the cumulative working time of the cooling cycle may have reached the defrosting reference time.

[0018] In this embodiment, the defrosting reference time can be shortened based on the opening time of the door used to open and close the storage compartment, and the cumulative working time of the cooling cycle may reach the shortened reference time when the defrosting start condition is met.

[0019] In this embodiment, the refrigerator may further include: an evaporator sensor for sensing the temperature of the evaporator or the temperature around the evaporator; and a temperature sensor for sensing the temperature of the storage compartment.

[0020] In this case, when the defrost delay condition is met, the difference between the temperature of the storage compartment sensed by the temperature sensor and the temperature sensed by the evaporator sensor may be less than the reference temperature value.

[0021] Alternatively, the refrigerator may also include an evaporator sensor for sensing the temperature of the evaporator or the temperature around the evaporator. In this case, during the operation of the cooling cycle, the compressor may be turned on or off, and when the defrost delay condition is met, the difference between the temperature of the evaporator sensor at the time the compressor is turned on and the temperature of the evaporator sensor at the time the compressor is turned off may be less than a reference temperature value.

[0022] In this embodiment, the control unit can determine the delayed defrosting start time within a predetermined maximum delay time range.

[0023] The control unit can determine the delayed defrosting start time within the time interval following the minimum delay time interval within the maximum delay time range. The length of the minimum delay time can be half the length of the maximum delay time.

[0024] The refrigerator may also include a memory in which the operating status of the refrigerator per unit time based on the door opening information is stored.

[0025] The energy-saving or normal operating status of the refrigerator per unit time can be stored in the memory.

[0026] In this embodiment, the control unit can determine the delayed defrost start time, so that defrost operation begins in the interval where the energy-saving interval exists continuously.

[0027] When there is no energy-saving interval in the time interval after the minimum delay time interval, the control unit can control the defrosting operation to start immediately after the maximum delay time.

[0028] The defrosting operation may include a pre-defrosting step and a defrosting step. The defrosting heater may operate during the defrosting step.

[0029] The refrigerator control method of this embodiment may further include: a step of determining whether the defrosting operation is completed; and a step of performing post-defrosting operation when the defrosting operation is completed.

[0030] In this embodiment, the control unit can control the compressor to operate at a cooling power lower than the maximum cooling power during the defrosting operation.

[0031] While the compressor is operating at a cooling power less than the maximum cooling power, when the door of the storage compartment is sensed to be opened, the control unit can control the compressor to operate at the maximum cooling power.

[0032] In this embodiment, when the defrosting operation is completed within the energy-saving operation range, and the next range is also an energy-saving operation range, the control unit can control the compressor to operate at a cooling power less than the maximum cooling power during the operation after defrosting.

[0033] In this embodiment, regardless of whether the defrosting operation begins in the normal operating range or the energy-saving operating range, if the next range is the normal operating range, the control unit can control the compressor to operate at maximum cooling power.

[0034] According to another aspect, a refrigerator may include: an evaporator for supplying cold air to the storage compartment; a defrost heater for defrosting the evaporator; and a control unit for controlling the defrost heater.

[0035] The control unit determines whether the defrosting start condition is met, and when the defrosting start condition is met, it can determine whether the defrosting delay condition is met.

[0036] The system can control the defrosting operation to start immediately when the defrosting delay condition is not met, and to determine the delayed defrosting start time when the defrosting delay condition is met, and to start the defrosting operation at the delayed defrosting start time. Attached Figure Description

[0037] Figure 1 This is a schematic diagram illustrating the configuration of a refrigerator according to an embodiment of the present invention.

[0038] Figure 2 This is a block diagram of a refrigerator according to an embodiment of the present invention.

[0039] Figure 3 This is a flowchart illustrating, in a general sense, a method for controlling a refrigerator according to an embodiment of the present invention.

[0040] Figure 4 This is a diagram illustrating the operating state of a refrigerator stored in a memory for each unit of time according to an embodiment of the present invention.

[0041] Figure 5 This is a flowchart illustrating a defrosting operation method according to an embodiment of the present invention.

[0042] Figure 6A , Figure 6B , Figure 6C This is a graph used to illustrate the time point at which defrosting begins after the defrosting delay conditions are met.

[0043] Figure 7A , Figure 7B , Figure 7C This is a diagram illustrating the cooling power of the compressor during defrosting operation according to an embodiment of the present invention. Detailed Implementation

[0044] Hereinafter, some embodiments of the present invention will be described in detail with reference to the exemplary accompanying drawings. When affixing reference numerals to the constituent elements of the various drawings, it should be noted that, for the same constituent elements, even if they are labeled in different drawings, they should be labeled with the same reference numerals as much as possible. Furthermore, when describing embodiments of the present invention, detailed descriptions of well-known structures or functions will be omitted if it is determined that such detailed descriptions may affect the understanding of the embodiments of the present invention.

[0045] Furthermore, when describing the constituent elements of embodiments of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are not used to define the nature, order, or sequence of the corresponding constituent elements, but only to distinguish the corresponding constituent element from other constituent elements. It should be noted that if the specification describes one constituent element as being "connected," "joined," or "linked" to another constituent element, the former constituent element may be directly connected to or in contact with the latter constituent element, or may be "connected," "joined," or "in contact" with the latter constituent element through another constituent element.

[0046] Figure 1 This is a schematic diagram illustrating the configuration of a refrigerator according to an embodiment of the present invention. Figure 2 This is a block diagram of a refrigerator according to an embodiment of the present invention.

[0047] Reference Figure 1 and Figure 2 According to one embodiment of the present invention, the refrigerator 1 may include: a cabinet 10, which has a freezer compartment 111 and a refrigerator compartment 112 inside; and a door (not shown), which is attached to the cabinet 10 and opens and closes the freezer compartment 111 and the refrigerator compartment 112 respectively.

[0048] The freezer compartment 111 and the refrigerator compartment 112 can be separated inside the cabinet 10 by a partition wall 113 in a left-right or up-down direction.

[0049] The refrigerator 1 may also include a compressor 21, a condenser 22, an expansion member 23, a freezer evaporator 24 (or may be referred to as a "first evaporator") for cooling the freezer compartment 111, and a refrigerator evaporator 25 (or may be referred to as a "second evaporator") for cooling the refrigerator compartment 112.

[0050] The refrigerator 1 may include a switching valve 26 for allowing refrigerant passing through the expansion member 23 to flow to either the freezer evaporator 24 or the refrigerator evaporator 25.

[0051] In this embodiment, the state in which the switching valve 26 operates to allow refrigerant to flow to the evaporator 24 of the freezer compartment can be referred to as the first state of the switching valve 26.

[0052] Additionally, the state in which the switching valve 26 operates to allow refrigerant to flow to the evaporator 25 for the refrigerator compartment can be referred to as the second state of the switching valve 26. As an example, the switching valve 26 may be a three-way valve.

[0053] The switching valve 26 can selectively open either a first refrigerant passage or a second refrigerant passage. The first refrigerant passage is connected to allow refrigerant to flow between the compressor 21 and the evaporator 25 for the refrigerator compartment, while the second refrigerant passage is connected to allow refrigerant to flow between the compressor 21 and the evaporator 24 for the freezer compartment. Cooling of the refrigerator compartment 112 and cooling of the freezer compartment 111 can be alternated by this switching valve 26.

[0054] The refrigerator 1 may further include: a freezer fan 28 (which may be referred to as a "first air supply fan") for supplying air to the freezer evaporator 24; a first motor 27 for rotating the freezer fan 28; a refrigerator fan 29 (which may be referred to as a "second air supply fan") for supplying air to the refrigerator evaporator 25; and a second motor 30 for rotating the refrigerator fan 29.

[0055] In this embodiment, the series of cycles in which the refrigerant flows through the compressor 21, condenser 22, expansion member 23 and evaporator 24 for the freezer compartment is called the "freezing cycle", and the series of cycles in which the refrigerant flows through the compressor 21, condenser 22, expansion member 23 and evaporator 25 for the refrigerator compartment is called the "refrigeration cycle".

[0056] "Refrigeration cycle operation" means that the compressor 21 is turned on and the refrigerator compartment fan 29 rotates, and the refrigerant flows through the switching valve 26 to the refrigerator compartment evaporator 25, so that the refrigerant flowing in the refrigerator compartment evaporator 25 exchanges heat with the air.

[0057] "Refrigeration cycle operation" means that the compressor 21 is turned on and the freezer fan 29 rotates, and the refrigerant flows through the switching valve 26 to the freezer evaporator 24, so that the refrigerant flowing in the freezer evaporator 24 exchanges heat with the air.

[0058] In the above description, an expansion member 23 is described as being located upstream of the switching valve 26. However, alternatively, a first expansion member may be provided between the switching valve 26 and the freezer evaporator 24, and a second expansion member may be provided between the switching valve 26 and the refrigerator evaporator 25.

[0059] As another example, a first valve can be provided on the inlet side of the evaporator 24 for the freezer compartment, and a second valve can be provided on the inlet side of the evaporator 25 for the refrigerator compartment, without using the switching valve 26. Then, during the freezing cycle, the first valve is turned on and the second valve can be turned off, and during the refrigeration cycle, the first valve is turned off and the second valve can be turned on.

[0060] The refrigerator 1 may include: a freezer temperature sensor 41 for sensing the temperature of the freezer 111; a refrigerator temperature sensor 42 for sensing the temperature of the refrigerator 112; an input unit 43 for inputting a target temperature (or desired temperature) for each of the freezer 111 and the refrigerator 112; and a control unit 50 for controlling the cooling cycle (including the freezing cycle and the refrigerator cycle) based on the input target temperature and the temperature sensed by the temperature sensors 41 and 42.

[0061] In this specification, temperatures below the target temperature of the freezer compartment 111 are referred to as the first freezer compartment reference temperature (or the third reference temperature), and temperatures above the target temperature of the freezer compartment 111 are referred to as the second freezer compartment reference temperature (or the fourth reference temperature). The range between the first freezer compartment reference temperature and the second freezer compartment reference temperature is referred to as the freezer compartment set temperature range.

[0062] Although not restricted, the target temperature of the freezer compartment 111 can be the average of the first freezer compartment reference temperature and the second freezer compartment reference temperature.

[0063] In this specification, the temperature below the target temperature of the refrigerator compartment 112 is referred to as the first refrigerator compartment reference temperature (or first reference temperature), and the temperature above the target temperature of the refrigerator compartment 112 is referred to as the second refrigerator compartment reference temperature (second reference temperature). The range between the first refrigerator compartment reference temperature and the second refrigerator compartment reference temperature is referred to as the refrigerator compartment set temperature range.

[0064] Although not restricted, the target temperature of the refrigerator compartment 112 can be the average of the first refrigerator compartment reference temperature and the second refrigerator compartment reference temperature.

[0065] In this embodiment, the user can set a target temperature for each of the freezer compartment 111 and the refrigerator compartment 112.

[0066] The control unit 50 can control the temperature of the refrigerator compartment 112 to remain within a temperature range that is within the set temperature range of the refrigerator compartment. Alternatively, the control unit 50 can control the temperature of the freezer compartment 111 to remain within a temperature range that is within the set temperature range of the freezer compartment.

[0067] At this time, the upper limit temperature of the temperature range is lower than the reference temperature of the second refrigerator compartment, and the lower limit temperature can be set to be higher than the reference temperature of the first refrigerator compartment.

[0068] In this embodiment, the control unit 50 can control the refrigeration cycle, the freezing cycle, and the vacuum operation to form one operating cycle. Alternatively, the compressor 21 can stop after the vacuum operation.

[0069] In this embodiment, evacuation operation refers to operating the compressor 21 while the refrigerant supply to all multiple evaporators is blocked, thereby collecting the refrigerant remaining in each of the evaporators into the compressor.

[0070] The control unit 50 controls the operation of the refrigeration cycle, and when the stop condition of the refrigeration cycle (also known as the start condition of the freezing cycle) is met, it can control the operation of the freezing cycle. During the control of the freezing cycle, if the stop condition of the freezing cycle is met, the evacuation operation can be performed.

[0071] In this embodiment, the evacuation operation can be omitted under special conditions. In this case, the refrigeration cycle and the freezing cycle can operate alternately. At this time, the refrigeration cycle and the freezing cycle can constitute one operating cycle.

[0072] As an example, the evacuation operation can be omitted when the external gas temperature is low.

[0073] On the other hand, the refrigerator 1 may also include a memory 45 in which the temperature of each of the freezer compartment 111 and the refrigerator compartment 112 is stored during the cooling cycle.

[0074] The refrigerator 1 may further include: a first defrost heater 48 for defrosting the evaporator 24 of the freezer compartment; and a second defrost heater 49 for defrosting the evaporator 25 of the refrigerator compartment.

[0075] The refrigerator 1 may further include: a first evaporator sensor 43 for sensing the temperature of the freezer evaporator 24 or the temperature around the freezer evaporator 24; and a second evaporator sensor 44 for sensing the temperature of the refrigerator evaporator 25 or the temperature around the refrigerator evaporator 25.

[0076] The refrigerator 1 may further include: a first door opening sensor 46 for sensing that the freezer door is open; and a second door opening sensor 47 for sensing that the refrigerator door is open.

[0077] When the cumulative working time of the freezing cycle reaches the first reference time (defrost reference time), the control unit 50 can determine that the defrost start condition of the evaporator 24 for the freezer compartment has been met.

[0078] If, during the operation of the refrigeration cycle, the freezer door is sensed to be open, the length of the first reference time may be shortened proportionally to the opening time of the freezer door. In this specification, the shortened first reference time may be referred to as the shortened reference time.

[0079] For example, during the operation of the freezing cycle, if the cumulative operating time of the freezing cycle reaches the first reference time while the freezer door is not open, the control unit 50 can determine that the defrosting start condition of the freezer evaporator 24 has been met.

[0080] Conversely, if the freezer door is opened more than once during the operation of the freezing cycle, the control unit 50 can determine that the defrosting start condition of the freezer evaporator 24 has been met when the cumulative operating time of the freezing cycle reaches a third reference time (shortened reference time) that is less than the first reference time.

[0081] Similarly, if the cumulative working time of the refrigeration cycle reaches the second reference time (defrost reference time), the control unit 50 can determine that the defrost start condition of the evaporator 24 for the refrigeration compartment has been met.

[0082] At this time, if the refrigerator door is sensed to be open during the operation of the refrigeration cycle, the length of the second reference time may be shortened proportionally to the opening time of the refrigerator door. In this specification, the shortened second reference time may be referred to as the shortened reference time.

[0083] For example, during the operation of the refrigeration cycle, if the cumulative operating time of the refrigeration cycle reaches the second reference time while the refrigerator door is not open, the control unit 50 can determine that the defrosting start condition of the evaporator 25 for the refrigerator compartment has been met.

[0084] Conversely, if the refrigerator door is opened more than once during the operation of the refrigeration cycle, the control unit 50 can determine that the defrosting start condition of the evaporator 25 for the refrigerator compartment has been met when the cumulative operating time of the refrigeration cycle reaches a fourth reference time (shortened reference time) that is less than the second reference time.

[0085] In this embodiment, the defrosting operation methods of the freezer evaporator 24 and the refrigerator evaporator 25 can be applied equivalently.

[0086] In the following text, the freezer evaporator 24 and the refrigerator evaporator 25 will be collectively referred to as evaporators. Additionally, the first defrost heater 48 and the second defrost heater 49 will be collectively referred to as defrost heaters, and the first evaporator sensor 43 and the second evaporator sensor 44 will be collectively referred to as evaporator sensors. The freezer fan 28 and the refrigerator fan 29 will be collectively referred to as fans.

[0087] In this embodiment, the defrosting operation can be divided into a pre-defrosting step and a defrosting step that actually performs the defrosting.

[0088] The pre-defrosting step refers to the operation of lowering the temperature of the storage chamber before the defrosting heater is activated.

[0089] That is, since the temperature of the storage chamber will rise when the defrosting heater is working, the temperature of the storage chamber is lowered in advance to cope with the temperature rise of the storage chamber.

[0090] The pre-defrosting steps may consist of multiple steps. As an example, the multiple steps may include steps one through three.

[0091] In the first step, the fan speed can be increased compared to normal operation during the cooling cycle. That is, during the normal cooling cycle, the fan speed is a first RPM, and in the first step of the defrosting operation, the fan speed can be a second RPM, which is greater than the first RPM.

[0092] The first step can be terminated when the time limit has elapsed, or when the temperature of the storage room reaches a temperature that is one temperature limit lower than the set temperature, or when the temperature of the external gas reaches a temperature below the external gas reference temperature.

[0093] In the second step, the compressor 21 is disconnected, and the fan can operate at a third RPM greater than the second RPM. The second step can be the vacuum operation described above.

[0094] In the third step, the compressor 21 is disconnected, and the blower fan can operate at a fourth RPM setting time that is less than the first RPM.

[0095] It should be noted that, in this embodiment, some steps in the detailed steps included in the pre-defrosting steps may be omitted or replaced with other steps.

[0096] After the pre-defrosting steps are completed, the defrosting steps can begin.

[0097] During the defrosting step, the defrosting heater can be activated to melt the frost on the evaporator.

[0098] During the operation of the defrosting heater, when the temperature sensed by the evaporator sensor reaches the defrosting end temperature, the control unit 50 can determine that defrosting is complete.

[0099] However, it should be noted that there are no restrictions on the method for determining whether defrosting is complete in this embodiment.

[0100] The control method of the refrigerator in this embodiment will be described below.

[0101] Figure 3 This is a flowchart used to schematically illustrate a refrigerator control method according to an embodiment of the present invention. Figure 4 This is a diagram illustrating the operating state of a refrigerator stored in a memory for each unit of time according to an embodiment of the present invention.

[0102] First, refer to Figure 3 The power supply to refrigerator 1 is turned on (S1). When the power supply to refrigerator 1 is turned on, refrigerator 1 can operate to cool the freezer compartment 111 or the refrigerator compartment 112.

[0103] The following describes, by way of example, a method for controlling a refrigerator when cooling the freezer compartment 111 after cooling the refrigerator compartment 112.

[0104] The control unit 50 controls the refrigeration cycle to cool the refrigeration compartment 112 (S2).

[0105] As an example, the control unit 50 can turn on the compressor 21 and rotate the refrigerator compartment fan 29. The control unit 50 switches the switching valve 26 to a first state to allow refrigerant to flow to the refrigerator compartment evaporator 25.

[0106] When the refrigeration cycle is in operation, the freezer fan 28 remains stopped.

[0107] Then, the refrigerant, after being compressed in the compressor 21 and passing through the condenser 22, flows through the switching valve 26 to the evaporator 25 for the refrigerator compartment. The refrigerant that flows and evaporates in the evaporator 25 for the refrigerator compartment flows back into the compressor 21.

[0108] Air that exchanges heat with the evaporator 25 of the refrigerator compartment is supplied to the refrigerator compartment 112. As a result, the temperature of the refrigerator compartment 112 decreases, while the temperature of the freezer compartment 111 increases.

[0109] During the operation of the refrigeration cycle, the control unit 50 determines whether the stop condition (S3) of the refrigeration cycle is met. That is, the control unit 50 determines whether the start condition of the freezing cycle is met.

[0110] As an example, when the temperature of the refrigerator compartment 112 reaches below the first refrigerator compartment reference temperature, the control unit 50 can determine that the stop condition of the refrigeration cycle has been met. Conversely, when the temperature of the refrigerator compartment 112 reaches above the second refrigerator compartment reference temperature, the control unit 50 can determine that the start condition of the refrigeration cycle has been met.

[0111] If the determination result of step S3 indicates that the start condition of the freezing cycle has been met, then the control unit 50 controls the freezing cycle to operate (S4).

[0112] As an example, the control unit 50 switches the switching valve 26 to a second state, allowing refrigerant to flow to the evaporator 24 in the freezer compartment. Even when switching from the refrigeration cycle to the refrigeration cycle, the compressor 21 continues to operate without stopping.

[0113] The control unit 50 rotates the freezer fan 28 and stops the refrigerator fan 29.

[0114] The control unit 50 can determine whether the stopping condition of the refrigeration cycle is met during the operation of the refrigeration cycle (S5).

[0115] As an example, the freezing cycle can be stopped when the temperature of the refrigerator compartment 112 reaches or exceeds the reference temperature of the second refrigerator compartment.

[0116] When the freezing cycle stops, the evacuation operation (S6) can be performed. As long as the power supply to the refrigerator 1 remains on (S7), the control unit 50 resumes control of the refrigeration cycle.

[0117] During the operation of the freezing or refrigeration cycle, the control unit 50 can determine whether the evaporator needs to be defrosted.

[0118] On the other hand, refer to Figure 4 During the operation of the freezing cycle or refrigeration cycle, the operating status of the refrigerator generated based on the opening and closing information of the storage compartment door can be stored in the memory 45.

[0119] For example, the opening time of the storage room door and the opening time of each opening can be accumulated and stored in the memory 45.

[0120] Based on the opening and closing information of the storage compartment door accumulated in the memory 45, the control unit 50 can determine the operating status of the refrigerator 1 for each unit of time.

[0121] The operating state of the refrigerator 1 can be divided into normal operation (refrigerator overuse range) and energy-saving operation.

[0122] For example, based on information accumulated weekly or monthly, the control unit 50 can determine the overuse period of the refrigerator 1.

[0123] Although unrestricted, the control unit 50 can determine the weeks and time periods in which the number of times the storage room door is opened exceeds a reference number within a unit of time, and / or the weeks and time periods in which the door is opened once exceeds a reference time, as overuse intervals.

[0124] The overuse zone thus determined can be changed based on accumulated storage room door opening information.

[0125] This overuse period is defined as the normal operating period, and the remaining periods can be defined as energy-saving operating periods. The refrigerator 1 operates according to a predetermined operating state for each unit of time.

[0126] That is, the past operating state of refrigerator 1 is stored in the memory 45 and it is envisioned as the future operating state of refrigerator 1.

[0127] Therefore, during the upcoming normal operating period, the user's opening and closing of the door can be sensed, which may cause the temperature of the storage compartment to rise. Therefore, in order to delay the temperature rise of the storage compartment, the cooling power of the compressor 21 can be maintained in the cooling cycle.

[0128] Conversely, during the upcoming energy-saving operating period, the door may not be opened or may be opened less frequently, thus reducing the likelihood of the storage room temperature rising.

[0129] Therefore, in this case, even if the cooling power of the compressor 21 is reduced, the temperature of the storage compartment will not rise or will rise slowly, thus reducing the power consumption corresponding to the reduced cooling power of the compressor 21.

[0130] Figure 5 This is a flowchart illustrating a defrosting operation method according to an embodiment of the present invention. Figure 6A , Figure 6B , Figure 6C This is a graph used to illustrate the time point at which defrosting begins after the defrosting delay conditions are met.

[0131] Figure 7A , Figure 7B , Figure 7CThis is a diagram illustrating the cooling power of the compressor during defrosting operation according to an embodiment of the present invention.

[0132] Reference Figures 5 to 7A , Figure 7B , Figure 7C The cooling cycle operates (S11) to cool the storage chamber.

[0133] During the operation of the cooling cycle, the control unit 50 determines whether the defrosting start condition is met (S12).

[0134] As described above, the control unit 50 can determine whether the cumulative working time of the cooling cycle has reached the defrosting reference time.

[0135] If the determination result of step S12 indicates that the defrosting start condition has been met, the control unit 50 can determine whether the defrosting delay condition (S12) is met.

[0136] When the defrost delay condition is met, the cumulative operating time of the cooling cycle reaches the shortened reference time, and the temperature difference between the storage chamber and the temperature sensed by the evaporator sensor is less than the reference temperature.

[0137] That is, if the door is opened more than once during the cooling cycle, and the temperature difference between the storage chamber and the temperature sensed by the evaporator sensor is less than the reference temperature value, it can be determined that the defrosting delay condition has been met.

[0138] When the temperature difference between the storage compartment and the temperature sensed by the evaporator sensor is less than a reference temperature value, the amount of frost is less than the reference value, so defrosting is not required at the current time.

[0139] Specifically, as the amount of frost on the evaporator increases, the evaporation temperature will decrease, and thus the temperature sensed by the evaporator sensor will decrease.

[0140] Therefore, as the amount of frost increases, the temperature difference between the storage compartment and the temperature sensed by the evaporator sensor gradually increases.

[0141] In this embodiment, when the amount of frost is above the reference amount, it is determined that the evaporator needs to be defrosted.

[0142] As a result, when the cumulative operating time of the cooling cycle reaches the shortened reference time, but the temperature difference between the storage chamber and the temperature sensed by the evaporator sensor is above the reference temperature value, defrosting can begin immediately without delay.

[0143] Conversely, when the cumulative operating time of the cooling cycle reaches a shortened reference time, and the temperature difference between the storage chamber and the temperature sensed by the evaporator sensor is less than the reference temperature value, it can be determined that defrosting is delayed.

[0144] Depending on the type of refrigerator, the temperature sensor that senses the temperature of the storage compartment may be omitted. In this case, the control unit 50 can determine whether to delay defrosting based on the temperature change sensed by the evaporator sensor.

[0145] Specifically, the compressor 21 can be repeatedly switched on and off. When the compressor 21 is on, the temperature sensed by the evaporator sensor will decrease, and when the compressor 21 is off, the temperature sensed by the evaporator sensor will increase.

[0146] As the amount of frost on the evaporator increases, the evaporation temperature will decrease. Therefore, the difference between the temperature sensed by the evaporator sensor at the time the compressor 21 is turned on (referred to as the on-time temperature) and the temperature sensed by the evaporator sensor at the time the compressor 21 is turned off (referred to as the off-time temperature) will increase.

[0147] Therefore, when the cumulative working time of the cooling cycle reaches the shortened reference time, and the difference between the on-time temperature and the off-time temperature of the evaporator sensor is less than the set temperature value, the control unit 50 can determine to delay defrosting.

[0148] If the result of step S13 indicates that the defrosting delay condition is not met, the defrosting operation begins immediately (S16). That is, the pre-defrosting steps are performed, and then the defrosting steps can be performed.

[0149] Conversely, when the determination result of step S13 indicates that the defrosting delay condition has been met, the control unit 50 can determine the delayed defrosting start time based on the operating status stored in the memory 45 for each unit of time (S14). The control unit 50 controls the defrosting to begin at the determined defrosting start time (S15). That is, the pre-defrosting steps are performed at the determined defrosting start time, and then the defrosting steps can be performed.

[0150] As an example, the control unit 50 can determine the delayed defrosting start time within a predetermined maximum delay time range.

[0151] In this specification, the unit of time is 1 hour, and the maximum delay time range can be 2 × N hours. Figure 6A , Figure 6B , Figure 6C In this example, N can be 4.

[0152] Reference Figure 6A , Figure 6B , Figure 6C The operating status for each unit of time is stored in memory 45. As an example, it can be determined that the defrost delay condition is met within the normal operating range.

[0153] In this case, the control unit 50 can determine the defrosting start time within the maximum delay time range (2×N).

[0154] The control unit 50 can first determine the defrosting start time within an interval after a small delay time (N hours).

[0155] When the defrost delay condition is met, defrosting must begin after the minimum delay time (N hours) in order to achieve the power consumption reduction effect brought about by the defrost delay.

[0156] Therefore, the control unit 50 can determine the defrosting start time within the defrosting interval after the minimum delay time (N hours).

[0157] In this embodiment, when the energy-saving operation interval in the defrostable interval continues for 2 hours, the control unit 50 can control the defrosting to start in the interval where energy-saving operation begins.

[0158] Reference Figure 6A and 6B Within the defrostable interval after the minimum delay time, the energy-saving operation interval can exist continuously for 2 hours.

[0159] Then, the control unit 50 can generate a start command in the interval immediately preceding the energy-saving operation interval so that defrosting can begin in the energy-saving operation interval. If a unit of time has elapsed after the command is generated (for example, 1 hour), defrosting can begin.

[0160] Conversely, refer to Figure 6C If there is no continuous 2-hour energy-saving operation interval in the defrosting interval after the minimum delay time, the control unit 50 can control the defrosting to start immediately after the maximum delay time.

[0161] That is, the control unit 50 can generate a start command before the maximum delay time of 1 hour has elapsed. Then, when the maximum delay time has elapsed, defrosting can begin immediately.

[0162] After the maximum delay time has elapsed, the need to begin defrosting is greater than the need for a defrosting delay.

[0163] That is, defrosting is delayed to reduce power consumption. However, when the defrosting delay is too long, it will cause the defrosting to be delayed until after the time when defrosting is needed, which will reduce the cycle performance and may result in increased power consumption.

[0164] Therefore, by setting the maximum delay time, defrosting is performed continuously within the energy-saving operating range before the maximum delay time has elapsed, and if defrosting fails to start within the maximum delay time range, defrosting starts immediately after the maximum delay time has elapsed, thereby effectively reducing power consumption.

[0165] After the defrosting operation begins, the control unit 50 can determine whether the defrosting operation is complete (S17). If it is determined that the defrosting operation is complete, the control unit 50 controls the execution of post-defrosting operation (S18).

[0166] In this embodiment, operation after defrosting refers to disconnecting the defrost heater and enabling the cooling cycle to operate, thereby reducing the temperature of the storage compartment.

[0167] Defrosting begins when the energy-saving operating range exists continuously for 2 hours. This is to minimize the additional temperature rise in the storage room after defrosting, while also reducing power consumption.

[0168] For example, during defrosting operation, the defrosting heater operates and the cooling cycle stops, so the heat from the defrosting heater will raise the temperature of the storage compartment.

[0169] Therefore, when the defrosting operation is completed, the temperature of the storage compartment will usually deviate from the set temperature range.

[0170] In this case, after the defrosting operation is completed, it is necessary to quickly reduce the temperature of the storage compartment.

[0171] As an example, after the defrosting operation is complete, it is advisable to operate the compressor 21 at its maximum cooling power during the cooling cycle. In this case, the temperature of the storage compartment can be rapidly reduced, but since the compressor 21 is operating at its maximum cooling power, the power consumption is relatively high.

[0172] However, when the waiting time before the user takes out the food is long, even if the compressor 21 operates at a cooling power lower than its maximum cooling power and does not maximize the cooling power of the compressor 21, the temperature of the storage compartment (the temperature of the food) can still be maintained within the set temperature range before the user takes out the food.

[0173] In this case, although the temperature of the storage compartment drops slightly slower, it has the advantage of low power consumption because the cooling power of the compressor 21 is less than the maximum cooling power.

[0174] Therefore, in this embodiment, when the defrosting operation is completed within the energy-saving operation range, and the next range is also an energy-saving operation range, the control unit 50 can control the compressor 21 to operate at a cooling power less than the maximum cooling power during the defrosting operation.

[0175] Reference Figure 7A Since the probability of users opening the door is low during the energy-saving operation range, even if the compressor 21 operates at a cooling power lower than the maximum cooling power during defrosting, it can still reduce the temperature of the storage compartment without being affected by the rise in external temperature.

[0176] Conversely, refer to Figure 7B It can start defrosting and then operate within the normal operating range. Under these circumstances, the probability of the user opening the door during operation after defrosting is relatively high.

[0177] Although the temperature of the storage compartment has already increased during the defrosting process, the temperature of the storage compartment will increase further when the user opens the door.

[0178] In this state, if the compressor 21 operates at a cooling power less than the maximum cooling power, the temperature of the storage compartment drops slowly, and it takes a long time for the temperature of the storage compartment to enter the set temperature range.

[0179] Therefore, when defrosting is completed within the normal operating range and operation begins after defrosting, the control unit 50 can control the compressor 21 to operate at maximum cooling power.

[0180] In addition, when defrosting begins in the energy-saving operating range, but the next range is the normal operating range, the control unit 50 can also control the compressor 21 to operate at maximum cooling power.

[0181] On the other hand, refer to Figure 7C When the compressor 21 is operating at a cooling power less than its maximum cooling power, the control unit 50 can control the compressor 21 to operate at its maximum cooling power when it senses that the door of the storage compartment has been opened.

[0182] If the door of the storage compartment is sensed to be opened while the compressor 21 is operating at a cooling power less than its maximum cooling power, it can be anticipated that the temperature of the storage compartment will rise. Therefore, the compressor 21 can operate at its maximum cooling power to rapidly lower the temperature of the storage compartment.

[0183] On the other hand, when the first step of the pre-defrosting process ends after the specified time, it indicates that the defrosting operation has started at a higher temperature in the storage room.

[0184] In this case, the temperature of the storage compartment is expected to be high after defrosting. Therefore, when the first step of the pre-defrosting process ends after the specified time, even if the defrosting operation is completed within the energy-saving range and the next range is also an energy-saving range, the compressor 21 can still operate at maximum cooling power.

[0185] According to this embodiment, even when the defrosting start conditions are met, the defrosting start can be delayed when it is possible to delay defrosting, thereby preventing unnecessary power consumption increases caused by defrosting.

[0186] In addition, according to this embodiment, after the defrosting operation is completed, the cooling power of the compressor can be determined based on the user's refrigerator usage mode, thereby preventing unnecessary power consumption increase during operation after defrosting.

[0187] It should be noted that, in the above embodiment, as an example, a defrosting operation method in a refrigerator including one compressor and two evaporators is described, but it is not limited thereto. The same defrosting operation method as in this embodiment can also be applied to refrigerators including one compressor and one evaporator as well as refrigerators including two compressors and two evaporators.

Claims

1. A refrigerator, wherein, Compressor; Evaporator for supplying cold air to a storage compartment; Fan for blowing air to the evaporator; Defrosting heater operated for defrosting the evaporator; Memory storing an operating state of the refrigerator per unit time based on opening information of a door of the storage compartment; and Control portion for controlling the defrosting heater; During operation of the cooling cycle, the control portion determines whether a defrost start condition is satisfied; If the defrost start condition is satisfied, the control portion determines whether a defrost delay condition is satisfied; If the defrost delay condition is not satisfied, the control portion causes the defrost operation to be started immediately; If the defrost delay condition is satisfied, the control portion determines a delayed defrost start time and causes the defrost operation to be started at the delayed defrost start time; The defrost start condition is satisfied in a case where an accumulated operation time of the cooling cycle reaches a defrost reference time; In the memory, an energy saving operation or a normal operation state of the refrigerator per unit time is stored; The control portion determines the delayed defrost start time so that the defrost operation is started in an interval where an energy saving operation interval continuously exists; The defrost operation includes a pre-defrost step and a defrost step in which the defrosting heater is operated; The pre-defrost step includes a plurality of steps including a first step and a second step; An RPM of the fan in the first step is different from an RPM of the fan in the second step; The RPM of the fan in the first step and the RPM of the fan in the second step are greater than an RPM of the fan during operation of the cooling cycle. 2.The refrigerator of claim 1, wherein The RPM of the fan in the second step is greater than the RPM of the fan in the first step. 3.The refrigerator of claim 2, wherein In the second step, the compressor is turned off. 4.The refrigerator of claim 1 or 2, wherein The plurality of steps further include a third step after the second step; An RPM of the fan in the third step is different from the RPM of the fan in the first step and the RPM of the fan in the second step. 5.The refrigerator of claim 4, wherein The RPM of the fan in the third step is less than the RPM of the fan during operation of the cooling cycle; In the third step, the compressor is turned off. 6.The refrigerator of claim 1, wherein The first step ends if a limit time elapses, or a temperature of the storage compartment reaches a temperature lower than a set temperature by a limit temperature, or an outside air temperature reaches a temperature lower than an outside air reference temperature. 7.The refrigerator of claim 6, wherein The defrost operation further includes a post-defrost operation after the defrost step; If a time point at which the defrost step is completed is in an energy saving operation interval and a next interval is continuously an energy saving operation interval, the compressor is operated at a cooling power less than a maximum cooling power during the post-defrost operation. ​ ​ If the first step in the pre-defrosting steps ends due to the passage of the limit time, the compressor operates at the maximum cooling power even if the time point at which the defrost operation is completed is in the energy saving range and the next range is continuously the energy saving range. 8.The refrigerator of claim 7, wherein, If the next range is the normal operation range in the case where the post-defrosting operation is started in the normal operation range or in the case where the post-defrosting operation is started in the energy saving operation range, the compressor operates at the maximum cooling power. 9.The refrigerator of claim 1, wherein, The control portion determines a deferral defrost start time in a time range after a minimum deferral time range within a predetermined maximum deferral time range; If the energy saving operation range is not continuously present in the time range after the minimum deferral time range, the control portion controls to start the defrost operation immediately after the passage of the maximum deferral time. 10.The refrigerator of claim 9, wherein, The minimum deferral time range is N hours; The maximum deferral time range is 2×N hours.

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