阅读说明：本技术 冰箱、加热器驱动装置、加热器驱动方法以及程序 (Refrigerator, heater driving device, heater driving method, and program ) 是由 清家刚 小林史典 儿玉拓也 于 2017-12-06 设计创作，主要内容包括：本发明的冰箱具备：冷却器；加热器单元(80),对冷却器进行加热；电流供给部(105),向加热器单元(80)供给电流；温度测定器(90),测定冷却器的温度；判定部(113),判定冷却器的测定温度与冰的融点的温度差的绝对值为基准温度差以下的状态的持续时间是否为基准时间以上,并且,判定是否达到了符合停止从电流供给部(105)向加热器单元(80)的电流供给的停止条件；以及加热器控制部(114),当由判定部(113)判定为前述的持续时间为基准时间以上时,控制电流供给部(105),使得加热器单元(80)的发热量增大,当由判定部(113)判定为达到了符合停止条件时,控制电流供给部(105),使得停止向加热器单元(80)的电流供给。(The refrigerator of the present invention comprises: a cooler; a heater unit (80) that heats the cooler; a current supply unit (105) that supplies current to the heater unit (80); a temperature measuring device (90) for measuring the temperature of the cooler; a determination unit (113) that determines whether or not the duration of a state in which the absolute value of the temperature difference between the measured temperature of the cooler and the melting point of ice is equal to or less than a reference temperature difference is equal to or greater than a reference time, and whether or not a stop condition for stopping the supply of current from the current supply unit (105) to the heater unit (80) has been met; and a heater control unit (114) that controls the current supply unit (105) so as to increase the amount of heat generated by the heater unit (80) when the determination unit (113) determines that the duration is equal to or longer than the reference time, and controls the current supply unit (105) so as to stop the supply of current to the heater unit (80) when the determination unit (113) determines that the stop condition is met.)

1. A refrigerator is provided with:

a cooler;

at least one heater unit heating the cooler;

a current supply unit that supplies current to the at least one heater unit;

at least one 1 st temperature detector for detecting the temperature of the cooler;

a determination unit configured to determine whether or not a duration of a state in which an absolute value of a temperature difference between a measured temperature measured by the at least one first temperature measuring device and a determination temperature corresponding to a measured temperature at which frost adhering to the cooler melts is equal to or greater than a preset reference temperature difference, and whether or not a stop condition for stopping supply of current from the current supply unit to the at least one heater unit is satisfied; and

and a heater control unit configured to control the current supply unit so that a heat generation amount of the at least one heater unit increases when the determination unit determines that the duration is equal to or longer than the reference time, and to control the current supply unit so that the supply of the current from the current supply unit to the at least one heater unit is stopped when the determination unit determines that the stop condition is satisfied.

2. The refrigerator according to claim 1,

further comprises a setting unit for setting the stop condition,

the stop condition is that the measured temperature is equal to or higher than an upper limit management temperature which is higher than the melting point of ice by at least the reference temperature difference,

when the determination unit determines that the duration is equal to or longer than the reference time, the setting unit sets the upper limit management temperature to a temperature higher than a preset temperature.

3. The refrigerator according to claim 1,

further comprises a setting unit for setting the stop condition,

the stop condition is that an elapsed time from the start of the supply of the current from the current supply unit to the heater unit is equal to or longer than a preset heater driving time,

when the determination unit determines that the duration is equal to or longer than the reference time, the setting unit sets the heater driving time to a time longer by a predetermined time or a time longer by a predetermined magnification.

4. The refrigerator according to claim 1,

further comprises a 2 nd temperature measuring device for measuring the temperature of at least one storage chamber,

the stop condition is that the measured temperature measured by the 2 nd temperature measuring device is equal to or higher than a preset storage room upper limit management temperature.

5. The refrigerator according to any one of claims 1 to 4,

the heater control portion controls the current supply portion so that a current value of the current supplied to the heater unit is changed from a 1 st current value to a 2 nd current value larger than the 1 st current value, whereby a heat generation amount of the heater unit increases.

6. The refrigerator according to any one of claims 1 to 4,

there are a plurality of the at least one heater unit,

the heater control unit controls the current supply unit to change from a 1 st state to a 2 nd state, thereby increasing the amount of heat generated by the entire plurality of heater units, the 1 st state being a state in which current is supplied to a 1 st number of heater units among the plurality of heater units, and the 2 nd state being a state in which current is supplied to a 2 nd number of heater units, which is greater than the 1 st number, among the plurality of heater units.

7. A heater driving device is provided with:

a current supply unit that supplies current to at least one heater unit that heats the cooler;

at least one 1 st temperature detector for detecting the temperature of the cooler;

a determination unit configured to determine whether or not a duration of a state in which an absolute value of a temperature difference between a measured temperature measured by the at least one first temperature measuring device and a determination temperature corresponding to a measured temperature at which frost adhering to the cooler melts is equal to or greater than a preset reference temperature difference, and whether or not a stop condition for stopping supply of current from the current supply unit to the at least one heater unit is satisfied; and

and a heater control unit configured to control the current supply unit so that a heat generation amount of the at least one heater unit increases when the determination unit determines that the duration is equal to or longer than the reference time, and to control the current supply unit so that the supply of the current from the current supply unit to the at least one heater unit is stopped when the determination unit determines that the stop condition is satisfied.

8. A heater driving method, comprising:

determining whether or not a duration of a state in which an absolute value of a temperature difference between a measured temperature measured by at least one 1 st temperature measuring device that measures a temperature of a cooler and a determination temperature corresponding to a measured temperature at which frost adhering to the cooler melts is equal to or less than a preset reference temperature difference is equal to or greater than a preset reference time;

determining whether or not a stop condition for stopping supply of electric current from a current supply unit that drives at least one heater unit that heats the cooler to the at least one heater unit is satisfied;

a step of controlling the current supply unit so that the amount of heat generation of the at least one heater unit increases when it is determined that the duration is equal to or longer than the reference time; and

and controlling the current supply section so that supply of the current from the current supply section to the at least one heater unit is stopped when it is determined that the stop condition is satisfied.

9. A program for causing a computer to function as a determination section and a heater control section:

the determination unit determines whether or not a duration of a state in which an absolute value of a temperature difference between a measured temperature measured by at least one 1 st temperature measuring device that measures a temperature of a cooler, and a determination temperature corresponding to a measured temperature at which frost adhering to the cooler melts, is equal to or less than a preset reference temperature difference, is equal to or more than a preset reference time, and determines whether or not a stop condition for stopping supply of electric current from a current supply unit to the at least one heater unit is satisfied, the current supply unit driving the at least one heater unit that heats the cooler,

the heater control unit controls the current supply unit so that the amount of heat generated by the at least one heater unit increases when the determination unit determines that the duration is equal to or longer than the reference time, and controls the current supply unit so that the supply of current from the current supply unit to the at least one heater unit is stopped when the determination unit determines that the stop condition is satisfied.

Technical Field

The invention relates to a refrigerator, a heater driving device, a heater driving method and a program.

Background

In the refrigerator, if frost adheres to the evaporator, heat exchange efficiency in the evaporator is reduced, and power consumption is increased accordingly. Therefore, a refrigerator including a heater for heating an evaporator to remove frost adhering to the evaporator has been proposed (for example, see patent document 1). The refrigerator described in patent document 1 includes: a defrosting heater that heats an evaporator that constitutes a part of a refrigeration cycle; a temperature sensor that detects a temperature of the evaporator or a vicinity thereof; and a control device for adjusting a defrosting end temperature or a cycle of executing a defrosting operation in a next defrosting operation based on a detected temperature of the temperature sensor within or after a predetermined time, wherein the refrigerator can prevent residual frost from being generated, maintain cooling performance of the evaporator, and suppress temperature rise of the storage chamber.

Disclosure of Invention

Problems to be solved by the invention

However, in the case where the evaporator to which frost is attached is heated by the defrosting heater, the temperature of the evaporator rises in a temperature region lower than 0 ℃, and when the temperature of the evaporator reaches a region near 0 ℃, the frost starts to melt. Thereby, the temperature of the evaporator is maintained at about 0 ℃ until all frost adhering to the evaporator is melted. Then, when frost attached to the evaporator is completely melted, the temperature of the evaporator starts to rise again.

In the refrigerator described in patent document 1, the defrosting end temperature in the next defrosting operation or the cycle of executing the defrosting operation is adjusted based on the detected temperature of the temperature sensor regardless of the time profile of the temperature of the evaporator. Therefore, for example, the following two cases cannot be distinguished: in an environment where it is difficult to transfer heat from the defrosting heater to the evaporator, the time until the evaporator reaches the defrosting end temperature is prolonged because the refrigerator is being used; and the time until the evaporator reaches the defrosting end temperature is prolonged due to frost adhering to the evaporator. Therefore, it is possible to set the defrosting end temperature during the defrosting operation high or shorten the cycle of the defrosting operation, although the amount of frost adhering to the evaporator is small. In this case, power consumption during the defrosting operation of the refrigerator increases, and the temperature in the refrigerator may increase.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a refrigerator, a heater driving device, a heater driving method, and a program that can suppress an increase in the temperature in the refrigerator while reducing the power consumption for defrosting.

Means for solving the problems

In order to achieve the above object, a refrigerator according to the present invention includes:

a cooler;

at least one heater unit heating the cooler;

a current supply unit that supplies current to the at least one heater unit;

at least one 1 st temperature detector for detecting the temperature of the cooler;

a determination unit configured to determine whether or not a duration of a state in which an absolute value of a temperature difference between a measured temperature measured by the at least one first temperature measuring device and a determination temperature corresponding to a measured temperature at which frost adhering to the cooler melts is equal to or greater than a preset reference temperature difference, and whether or not a stop condition for stopping supply of current from the current supply unit to the at least one heater unit is satisfied; and

and a heater control unit configured to control the current supply unit so that a heat generation amount of the at least one heater unit increases when the determination unit determines that the duration is equal to or longer than the reference time, and to control the current supply unit so that the supply of the current from the current supply unit to the at least one heater unit is stopped when the determination unit determines that the stop condition is satisfied.

Effects of the invention

According to the present invention, when the determination unit determines that the duration of the state in which the absolute value of the temperature difference between the measured temperature of the cooler and the determination temperature corresponding to the measured temperature at which frost adhering to the cooler melts is equal to or greater than the reference temperature difference is equal to or greater than the reference time, the heater control unit controls the current supply unit so that the amount of heat generated by at least one of the heaters increases. Thus, the amount of heat generated by the heater is set to an appropriate value according to the amount of frost adhering to the cooler without being affected by the fluctuation in the amount of heat transfer from the heater to the cooler due to the surrounding environment of the cooler or the size of the cooler. Therefore, the increase in the internal temperature of the refrigerator can be suppressed while reducing the power consumption for defrosting.

Drawings

Fig. 1 is a schematic front view of a refrigerator according to an embodiment of the present invention.

Fig. 2 is a schematic sectional view taken along line a-a shown in fig. 1.

Fig. 3 is a diagram showing a configuration of a refrigeration cycle according to the embodiment.

Fig. 4 is a rear view showing a configuration of a cooler in a cooler chamber of a refrigerator of the embodiment.

Fig. 5 is a perspective view of a cooler of a refrigerator of an embodiment.

Fig. 6 is a block diagram of a heater driving device of the embodiment.

Fig. 7 is a diagram showing the contents of the current value database according to the embodiment.

Fig. 8 is a graph showing time curves of the temperature of the cooler in the case where the amount of frost attached to the cooler is small and the case where the amount of frost attached to the cooler is large in the refrigerator according to the embodiment.

Fig. 9 is a flowchart showing an example of heater driving processing executed by the control device of the embodiment.

Fig. 10 is a graph showing a time curve of the temperature of the cooler in the case where the ambient environment of the cooler is different in the refrigerator according to the embodiment.

Fig. 11 is a block diagram of a heater driving device of the embodiment.

Fig. 12 is a schematic front view of a refrigerator according to an embodiment of the present invention.

Detailed Description

Hereinafter, a refrigerator according to an embodiment of the present invention will be described with reference to the drawings. The refrigerator of the present embodiment includes a heater for removing frost adhering to the cooler, a current supply unit for supplying current to the heater, and a heater control unit for controlling the current supply unit. The refrigerator further includes a 1 st temperature measuring device that measures the temperature of the cooler, and a determination unit that determines whether or not a duration of a state in which an absolute value of a temperature difference between the measured temperature measured by the 1 st temperature measuring device and a determination temperature corresponding to a measured temperature at which frost adhering to the cooler melts is equal to or less than a preset reference temperature difference is equal to or greater than a preset reference time. When the determination unit determines that the duration is equal to or longer than the reference time, the heater control unit controls the current supply unit so that the amount of heat generated by the heater is increased.

As shown in fig. 1, the refrigerator 1 of the present embodiment includes a plurality of storage compartments for storing foods. The refrigerator 1 includes a plurality of storage compartments, which are a refrigerating compartment 10 for refrigerating food, an ice-making compartment 11 for storing an ice maker, a switching compartment 12 for switching the compartment to a temperature at which ice can be made and a temperature other than the temperature, a vegetable compartment 13 for storing vegetables, and a freezing compartment 14 for storing frozen food and freezing the frozen food. In fig. 1, the left-right direction is an X-axis direction, the up-down direction is a Z-axis direction, and a direction orthogonal to the X-axis direction and the Z-axis direction is a Y-axis direction when viewed from the front side of the refrigerator 1. In refrigerator 1, vegetable compartment 13 and freezing compartment 14 may be arranged in a reversed manner in order to improve heat transfer efficiency during cold storage and freezing. In this case, it is preferable that freezing room 14 be disposed adjacent to ice making room 11 and switching room 12.

As shown in fig. 2, the refrigerator 1 includes a cooler chamber 16 and a machine chamber 18 connected to the cooler chamber 16 via a drain pipe 17. Cooler room 16 is connected to refrigerating room 10, ice making room 11, switching room 12, vegetable room 13, and freezing room 14 via cold air passage 15. The cooler chamber 16 houses a cooler 20 and a fan 30. The cooled air around the cooler 20 in the cooler chamber 16 is supplied to the refrigerating compartment 10, the ice making compartment 11, and the like through the cold air duct 15 by the fan 30. In addition, a compressor 40 is housed in the machine room 18. The refrigerator 1 further includes a defrost switch 95 operated by a user when frost adhering to the cooler 20 is removed, a heater unit 80 that heats the cooler 20, and a temperature measuring device 90 that measures the temperature of the cooler 20. The heater unit 80 includes a lower heater 80A disposed below the cooler 20 and a side heater 80B disposed on the side of the cooler 20. The temperature measuring device 90 corresponds to the 1 st temperature measuring device described in the claims. The refrigerator 1 further includes a heater driving device 100, and the heater driving device 100 drives the heater unit 80 based on the measured temperature of the cooler 20 when the defrost switch 95 is turned on.

As shown in fig. 3, the refrigerator 1 includes a condenser 50, a decompressor 60, and a suction pipe 70 in addition to the cooler 20 and the compressor 40. The condenser 50, the decompression unit 60, the cooler 20, the suction pipe 70, and the compressor 40 are connected to each other via a refrigerant pipe PI, thereby forming a refrigeration cycle 200. In the refrigeration cycle 200, the refrigerant flows through the condenser 50, the decompression unit 60, the cooler 20, the suction pipe 70, and the compressor 40 in this order. By circulating the refrigerant in the refrigeration cycle 200, the interior of each of the refrigerating chamber 10, the ice making chamber 11, the switching chamber 12, the vegetable chamber 13, and the freezing chamber 14 is lowered to a temperature at which food can be frozen or refrigerated.

The condenser 50 has a condenser pipe 51 and a condenser 52. The condensation pipe 51 is fixed to the housing 1a of the refrigerator 1 shown in fig. 1 and 2 via a fixing member, and dissipates heat to the housing of the refrigerator 1 to condense the refrigerant. Examples of the fixing member include an adhesive tape made of aluminum, an adhesive tape including copper foil, and the like. Returning to fig. 3, the condenser 52 is a fin-tube condenser having a condenser refrigerant tube and a fin joined to the condenser refrigerant tube, a wire-tube condenser having a condenser refrigerant tube and a wire covering the surface of the condenser refrigerant tube, or the like, and is disposed in the machine room 18. The condenser 52 condenses the refrigerant by radiating heat to fins, wires, and the like.

The decompression section 60 has an expansion valve 61 and a capillary tube 62. The decompression section 60 decompresses and expands the refrigerant condensed and liquefied by the condensation section 50 to evaporate a part of the refrigerant, thereby bringing the refrigerant into a two-phase state of liquid and gas.

As shown in fig. 4, the cooler 20 includes a cooler refrigerant pipe 21 and a plurality of fins 22 joined to the cooler refrigerant pipe 21, and heat of the cooler refrigerant pipe 21 is released to the outside air via the plurality of fins 22. The cooler 20 evaporates the refrigerant in a liquid state out of the two-phase refrigerant decompressed by the decompression unit 60, and cools the ambient air by the heat absorption action due to the evaporation of the refrigerant. The cooled air present around the cooler 20 is sent to the outside of the cooler compartment 16 by the fan 30.

As shown in fig. 4, the cooler refrigerant pipe 21 has a meandering shape in the XZ plane. The cooler refrigerant pipe 21 has a linear portion 211 extending linearly in the X-axis direction, and a bent portion 212 bent so as to connect respective end portions of two linear portions 211 adjacent in the Z-axis direction to each other. As shown in fig. 5, a plurality of the cooler refrigerant tubes 21 are provided in parallel with a space therebetween in the Y-axis direction. Fig. 5 shows a case where there are three cooler refrigerant pipes 21. As shown in fig. 4, the plurality of fins 22 are joined to the linear portions 211 of the plurality of cooler refrigerant tubes 21, respectively. As shown in fig. 5, the plurality of fins 22 are plate-like members formed of metal, and are arranged at intervals along the X-axis direction.

Returning to fig. 3, the suction pipe 70 is disposed in the heat insulating material 71 together with the capillary 62 of the decompression section 60, and is joined to the capillary 62. The suction tube 70 heats the refrigerant to a temperature close to the condensation temperature by heat exchange with the capillary tube 62. The compressor 40 compresses the refrigerant whose temperature has been raised in the suction pipe 70, and sends the compressed refrigerant to the condensation unit 50.

As shown in fig. 5, the heater unit 80 includes a lower heater 80A disposed below the cooler 20 and a side heater 80B disposed on the side of the cooler 20. By disposing the side heater 80B at the side of the cooler 20 in this way, the efficiency of removing frost adhering to the cooler 20 is improved. The lower heater 80A is a so-called carbon type heater including a glass tube which is a straight tube type and through which far infrared rays pass, and carbon fibers which are enclosed in the glass tube and are energized to radiate far infrared rays. Further, a heater top cover 81 is provided between the lower heater 80A and the cooler 20, and frost or water falling from the cooler 20 is prevented from contacting the lower heater 80A. The side heater 80B has a meandering tube-like glass tube that transmits infrared rays, and carbon fibers enclosed in the glass tube. The side heater 80B is disposed in a region extending from the center to the upper side of the region adjacent to the fins 22 of the cooler 20.

The temperature measuring device 90 has a thermistor whose resistance changes in accordance with a change in ambient temperature. The temperature measuring device 90 is disposed in the header portion 21a of the cooler refrigerant pipe 21 of the cooler 20, as shown in fig. 4, for example. By disposing the temperature measuring device 90 in the header part 21a in this way, it is possible to match the determination temperature corresponding to the measurement temperature measured by the temperature measuring device 90 when frost adhering to the cooler 20 melts, with the melting point of ice. The temperature measuring device 90 is not limited to a temperature measuring device having a thermistor, and may be another type of temperature measuring device such as a temperature measuring device using a thermocouple or a non-contact temperature measuring device such as a radiation thermometer.

The heater driving device 100 drives the heater unit 80 in two driving modes, a normal mode and a special mode, which increases the amount of heat generation of the heater unit 80 as compared with that in the normal mode. As shown in fig. 6, the heater driving device 100 includes a CPU (central processing unit) 101, a main storage unit 102 including a volatile memory, an auxiliary storage unit 103 including a non-volatile memory, an interface 104, a current supply unit 105 for supplying current to the heater unit 80, and a bus 109 for connecting the units. Examples of the nonvolatile memory include a magnetic disk and a semiconductor memory. The auxiliary storage unit 103 stores a program for executing a heater driving process described later. The interface 104 is connected to the temperature detector 90 and the defrost switch 95. The interface 104 converts the signal input from the defrost switch 95 into information indicating the on-off state of the defrost switch 95 and notifies the CPU 101. The interface 104 converts the signal input from the temperature measuring device 90 into temperature information and notifies the CPU101 of the temperature information.

The current supply unit 105 includes, for example, a rectifying and smoothing circuit that converts ac supplied from a system power supply into dc, and a power conversion circuit that performs constant current control of receiving power supply from the rectifying and smoothing circuit and supplying a constant dc to the heater unit 80. The current supply unit 105 supplies a predetermined dc current of a fixed current value to the heater unit 80 in the normal mode and the special mode, respectively. The bus 109 connects the CPU101, the main storage unit 102, the auxiliary storage unit 103, the interface 104, and the current supply unit 105 to each other.

The auxiliary storage unit 103 includes a reference database (hereinafter, referred to as "DB") 131 storing information on a determination reference, a time DB132 storing time information, and a current value DB133 storing information indicating a current value to be supplied to the heater unit 80. The reference DB131 stores information indicating the reference temperature difference, the reference time, the upper limit management temperature, and the heater driving time, respectively. Here, the reference temperature difference is a temperature that is a reference for an absolute value of a temperature difference between the temperature measured by the temperature measuring device 90 and the melting point of ice adhering to the cooler 20, and is set based on, for example, a measurement error of the temperature measuring device 90. The reference time is a time that is a reference for a duration of a state in which the absolute value of the temperature difference between the measured temperature measured by the temperature measuring device 90 and the melting point of ice is equal to or less than the reference temperature difference. The reference temperature difference and the reference time are determined by experiments in advance and are set in advance by a user. The upper limit management temperature is an upper limit temperature of the heater unit 80. The upper limit control temperature is set to a temperature higher than the melting point of ice by at least a temperature corresponding to the reference temperature difference. The heater driving time is a time from when the current supply unit 105 starts supplying the current to the heater unit 80 to when the current supply to the heater unit 80 is stopped. However, the heater driving device 100 of the present embodiment appropriately changes the upper limit management temperature, which is the upper limit temperature of the heater unit 80, and the heater driving time, which is the maximum time for driving the heater unit 80. Therefore, the reference DB131 stores information indicating the initial upper limit management temperature, which is the initial value of the upper limit management temperature, and the initial heater driving time, which is the initial value of the heater driving time, separately from information indicating the upper limit management temperature and the heater driving time. Each time a heater driving process described later is executed, information indicating the upper limit management temperature and the heater driving time is initially set as information indicating the initial upper limit management temperature and the initial heater driving time at the start of the process.

The time DB132 stores therein time information indicating a time when the state continues after the temperature difference between the measured temperature of the cooler 20 and the melting point of ice first becomes equal to or less than the reference temperature difference, and time information indicating a time when the absolute value of the temperature difference between the measured temperature of the cooler 20 and the melting point of ice is larger than the reference temperature difference, separately. The time DB132 also stores time information indicating the time immediately after the current supply from the current supply unit 105 to the heater unit 80 is started.

As shown in fig. 7, the current value DB133 stores information indicating the current value of the current supplied from the current supply portion 105 to the heater unit 80 in the normal mode and the current value of the current supplied from the current supply portion 105 to the heater unit 80 in the special mode.

Returning to fig. 6, the CPU101 reads out and executes the program stored in the auxiliary storage unit 103 to the main storage unit 102, and thereby functions as a temperature acquisition unit 111 that acquires the measured temperature of the cooler 20, a time counting unit 112 that counts the time, a determination unit 113, a heater control unit 114 that controls the current supply unit 105, and a setting unit 115 that sets the upper limit management temperature and the heater driving time. The temperature acquisition unit 111 acquires measurement temperature information indicating the temperature of the cooler 20 measured by the temperature measuring device 90 via the interface 104. The temperature acquisition unit 111 periodically acquires measured temperature information from the temperature measuring device 90, and stores the acquired measured temperature information in the main storage unit 102.

The timer unit 112 has a software timer, and generates time information indicating the current time and stores the time information in the time DB 132. The timer unit 112 discriminates between time information generated when the temperature difference between the measured temperature of the cooler 20 and the melting point of ice is equal to or less than the reference temperature difference and time information generated when the temperature difference between the measured temperature of the cooler 20 and the melting point of ice is greater than the reference temperature difference, and stores the time information in the time DB 132.

The determination unit 113 calculates a temperature difference between the temperature measured by the temperature measuring device 90 and the melting point of ice. Then, the determination unit 113 determines whether or not the duration of the state in which the calculated temperature difference is equal to or less than the reference temperature difference is equal to or greater than the reference time. The determination unit 113 determines whether or not a condition for stopping the supply of current from the current supply unit 105 to the heater unit 80 is satisfied. Specifically, the determination unit 113 determines whether or not the measured temperature of the cooler 20 is equal to or higher than the upper limit management temperature, and whether or not the elapsed time from the start of the supply of current to the heater unit 80 by the current supply unit 105 is equal to or longer than the heater driving time.

When determining unit 113 determines that the duration of the state in which the temperature difference between the measured temperature of cooler 20 and the melting point of ice is equal to or less than the reference temperature difference is equal to or greater than the reference time, heater control unit 114 controls current supply unit 105 so that the amount of heat generated by heater unit 80 is increased. Specifically, the heater control unit 114 controls the current supply unit 105 such that the current value of the current supplied from the current supply unit 105 to the heater unit 80 is changed from the 1 st current value to the 2 nd current value larger than the 1 st current value. When the determination unit 113 determines that the measured temperature of the cooler 20 is equal to or higher than the upper limit management temperature, the heater control unit 114 controls the current supply unit 105 so as to stop the supply of current from the current supply unit 105 to the heater unit 80.

The setting unit 115 sets a stop condition for stopping the supply of current from the current supply unit 105 to the heater unit 80. Specifically, when determining unit 113 determines that the duration of the state in which the absolute value of the temperature difference between the measured temperature of cooler 20 and the melting point of ice is equal to or less than the reference temperature difference is equal to or longer than the reference time, setting unit 115 sets the upper limit management temperature to a temperature higher than a preset temperature. For example, the initial value of the upper limit management temperature may be set to about 1 ℃, and the range of increase of the upper limit management temperature may be set to 1 ℃. When determining unit 113 determines that the duration of the state in which the temperature difference between the measured temperature of cooler 20 and the melting point of ice is equal to or less than the reference temperature difference is equal to or greater than the reference time, setting unit 115 sets the heater driving time to a time longer than a preset time. For example, the initial value of the heater driving time may be set to about 30 minutes, and the rising width of the heater driving time may be set to 5 minutes in advance.

Next, the operation of the heater driving device 100 according to the present embodiment will be described. A curve C1 in fig. 8 shows a time curve of the measured temperature of the cooler 20 measured by the temperature measuring device 90 in the case where frost adheres to the cooler 20. On the other hand, a curve C2 in fig. 8 shows a time curve of the measured temperature of the cooler 20 in the case where the amount of frost adhering to the cooler 20 is larger than that in the case of the curve C1. Here, the current value of the current supplied from the heater driving device 100 to the heater unit 80 is constant. As shown in fig. 8, the duration Δ Ti2 in the curve C2 is longer than the duration Δ Ti1 in the state where the absolute value of the temperature difference between the measured temperature of the cooler 20 and the melting point of ice is equal to or less than the reference temperature difference Δ Teth in the curve C1. This means that the more the amount of frost attached to the cooler 20, the longer the time required to completely melt the frost. Therefore, the heater driving device 100 according to the present embodiment is provided with the reference time Δ Tith that is longer than the duration time Δ Ti1 and shorter than the duration time Δ Ti2, for example. When the duration time Δ Ti2 becomes equal to or longer than the reference time Δ Tith, the heater driving device 100 increases the current value of the current supplied from the current supply unit 105 to the heater unit 80, thereby promoting melting of frost adhering to the cooler 20. In this way, the heater driving device 100 prevents wasteful supply of current from the current supply portion 105 to the heater unit 80 in a state where the amount of frost adhering to the cooler 20 is small.

Next, a heater driving process performed by the heater driving device 100 according to the present embodiment will be described with reference to fig. 9. This heater driving process is started, for example, when the user turns on the defrost switch 95.

First, the heater control section 114 controls the current supply section 105 so as to start the supply of current to the heater unit 80 (step S101). At this time, the setting unit 115 updates the information indicating the upper limit management temperature and the heater driving time stored in the reference DB131 to the information indicating the initial upper limit management temperature and the initial heater driving time stored in the reference DB 131.

Next, the timer unit 112 generates time information immediately after the heater driving process is started and stores the time information in the time DB132 (step S102).

Next, the determination unit 113 acquires information indicating the reference temperature difference Δ Teth and the reference time Δ Tith from the reference DB131 (step S103).

Then, the temperature acquisition unit 111 acquires, via the interface 104, measured temperature information indicating the temperature of the cooler 20 measured by the temperature measuring device 90 after a lapse of a certain time (step S104).

Next, the determination unit 113 calculates the absolute value of the temperature difference between the measured temperature indicated by the measured temperature information acquired by the temperature acquisition unit 111 and the melting point of ice (step S105), and determines whether or not the calculated absolute value of the temperature difference is equal to or less than the reference temperature difference (step S106). Here, in the processing of step S105, the determination unit 113 calculates the absolute value of the temperature difference between the melting point of ice and the highest measured temperature among the measured temperatures indicated by the measured temperature information obtained within the above-described certain period of time. For example, the maximum value of the measured temperature indicated by the measured temperature information acquired by the temperature acquisition unit 111 within a certain period of time is-2 ℃, and the reference temperature difference is set to 3 ℃. In this case, since the absolute value of the temperature difference between the maximum value of the measured temperature and the melting point (0 ℃) of ice is 2 ℃, the determination unit 113 determines that the absolute value (2 ℃) of the calculated temperature difference is equal to or less than the reference temperature difference (3 ℃).

When the determination unit 113 determines that the absolute value of the calculated temperature difference is smaller than the reference temperature difference Δ Teth (no in step S106), the time counting unit 112 generates time information indicating the time at that time and stores the time information in the time DB132 (step S107). Subsequently, the process of step S114 described later is executed.

On the other hand, when the determination unit 113 determines that the absolute value of the calculated temperature difference is equal to or greater than the reference temperature difference Δ Teth (yes in step S106), the time counting unit 112 generates time information indicating the time at that time and stores the time information in the time DB132 (step S108).

Then, the determination unit 113 calculates the duration of a state in which the absolute value of the temperature difference between the measured temperature of the cooler 20 and the melting point of ice is equal to or less than the reference temperature difference Δ Teth, based on the time information stored in the time DB132 (step S109), and determines whether or not the calculated duration is equal to or greater than the reference time Δ Tith (step S110). Here, the determination unit 113 calculates the difference between the earliest time and the latest time among the times during which the state is continued after the absolute value of the temperature difference between the measured temperature of the cooler 20 and the melting point of ice first becomes equal to or less than the reference temperature difference Δ Teth, and thereby obtains the duration time.

The determination unit 113 determines that the duration of the state in which the absolute value of the temperature difference between the measured temperature of the cooler 20 and the melting point of ice is equal to or less than the reference temperature difference Δ Teth is equal to or more than the reference time Δ Tith (step S110: yes). In this case, the heater control unit 114 determines whether or not the change of the drive mode has been performed (step S111). When it is determined that the change of the drive mode has not been performed (no in step S111), the heater control unit 114 changes the drive mode from the normal mode to the special mode (step S112). At this time, heater control unit 114 controls current supply unit 105 with reference to current value DB133 such that the current value of the current supplied to heater unit 80 is changed from 1 st current value I1, which corresponds to the normal mode, to 2 nd current value I2, which corresponds to the special mode and is larger than 1 st current value I1.

Then, the setting unit 115 changes the upper limit management temperature and the heater driving time (step S113). Specifically, the setting unit 115 updates the upper limit management temperature stored in the reference DB131 to a temperature higher than the initial upper limit management temperature by a preset temperature, and updates the heater driving time stored in the reference DB131 to a time longer than the initial heater driving time by a preset time. Then, the process of step S103 is executed again. On the other hand, when it is determined that the change of the drive mode has been performed (yes in step S111), the heater control unit 114 directly performs the process of step S103.

In the process of step S110 described above, the determination unit 113 determines that the duration of the state in which the absolute value of the temperature difference between the measured temperature of the cooler 20 and the melting point of ice is equal to or less than the reference temperature difference Δ Teth is less than the reference time Δ Tith (no in step S110). In this case, the determination unit 113 refers to the reference DB131 and determines whether or not the measured temperature indicated by the measured temperature information acquired by the temperature acquisition unit 111 is equal to or higher than the upper limit management temperature (step S114). Here, the determination unit 113 determines that the measured temperature indicated by the measured temperature information is equal to or higher than the upper limit managed temperature (YES in step S114). In this case, the heater control section 114 controls the current supply section 105 so as to stop the supply of current to the heater unit 80 (step S115), and the heater driving process ends. At this time, the defrost switch 95 is switched from the on state to the off state.

On the other hand, when determining that the measured temperature indicated by the measured temperature information is lower than the upper limit management temperature (no in step S114), the determination unit 113 refers to the time DB132 and calculates the elapsed time after the start of the current supply from the current supply unit 105 to the heater unit 80 (step S116). Next, the determination unit 113 refers to the time DB132, and determines whether or not the calculated elapsed time is equal to or longer than the heater driving time (step S117). When the determination unit 113 determines that the calculated elapsed time is shorter than the heater driving time (no in step S117), the process of step S104 is executed again.

On the other hand, when the determination unit 113 determines that the calculated elapsed time is equal to or longer than the heater driving time (yes in step S117), the heater control unit 114 controls the current supply unit 105 so as to stop the supply of current from the current supply unit 105 to the heater unit 80 (step S115), and the heater driving process ends. Further, while the heater driving device 100 is executing the heater driving process, in a case where the user forcibly turns off the defrost switch 95, the heater driving device 100 forcibly ends the heater driving process.

However, even if the amount of frost attached to the cooler 20 is the same, the time profile of the measured temperature of the cooler 20 may fluctuate due to differences in the ambient environment of the cooler 20. Curves C1 and C3 in fig. 10 show time curves of the measured temperature of the cooler 20 in the case where the same amount of frost is attached to the cooler 20. The curve C3 represents a time curve of the measured temperature in the case where the ambient environment of the cooler 20 is an environment in which heat is difficult to transfer from the heater unit 80 to the cooler 20, as compared with the ambient environment of the cooler 20 corresponding to the curve C1. This corresponds to, for example, the case of an environment in which heat generated in the heater unit 80 is easily transferred to the outside of the cooler 20 or the case where the amount of heat generated in the heater unit 80 is small. Here, the heater driving device is configured, for example, as follows: the amount of frost adhering to the cooler 20 is determined based on the time until the measured temperature of the cooler 20 becomes equal to or higher than a preset temperature. In this case, the heater driving device may erroneously determine that the amount of frost adhering to the cooler 20 is larger in the case of the curve C3 than in the case of the curve C1, and for example, the current value of the current supplied to the heater unit 80 may be wastefully increased. In this case, power is wastefully consumed in the heater unit 80.

In contrast, the heater driving device 100 of the present embodiment adjusts the current value of the current supplied to the heater unit 80 based on the duration Δ Ti1 and Δ Ti3 in which the absolute value of the temperature difference between the measured temperature of the cooler 20 and the melting point of ice is equal to or less than the reference temperature difference Δ Teth. Specifically, if the duration time Δ Ti1 or Δ Ti3 is shorter than the reference time Δ Tith, the heater driving device 100 does not change the current value of the current supplied to the heater unit 80. In this way, the heater driving device 100 appropriately adjusts the current value of the current supplied to the heater unit 80 based on the duration Δ Ti1 and Δ Ti3, which are the time consumed by the heat transferred from the heater unit 80 to the cooler 20 to melt the frost adhering to the cooler 20. Therefore, wasteful power consumption in the heater unit 80 is suppressed.

As described above, according to refrigerator 1 of the present embodiment, when determining unit 113 determines that the duration of the state in which the absolute value of the temperature difference between the measured temperature of cooler 20 and the melting point of ice is equal to or less than the reference temperature difference is equal to or greater than the reference time, heater control unit 114 controls current supply unit 105 so that the amount of heat generation of heater unit 80 increases. Thus, the heat generation amount of the heater unit 80 is set to an appropriate magnitude according to the adhesion amount of frost adhering to the cooler 20 without being affected by the fluctuation in the heat transfer amount from the heater unit 80 to the cooler 20 due to the surrounding environment of the cooler 20 or the size of the cooler 20. Therefore, it is possible to suppress an increase in the internal temperature of the refrigerator 1 while reducing the power consumption for defrosting, and it is possible to prevent a decrease in the quality of the food stored in the refrigerator 1.

When it is determined by the determination unit 113 that the duration of the state in which the absolute value of the temperature difference between the measured temperature of the cooler 20 and the melting point of ice is equal to or less than the reference temperature difference Δ Teth is equal to or longer than the reference time Δ Tith, the setting unit 115 of the present embodiment sets the upper limit management temperature to a temperature higher than a preset temperature, and sets the heater driving time to a time longer than a preset time. This suppresses the frost from remaining on the cooler 20, and therefore, has an advantage of reducing the power consumption of the refrigerator 1 after the heater driving process.

The heater control unit 114 of the present embodiment controls the current supply unit 105 such that the current value of the current supplied to the heater unit 80 is changed from the 1 st current value to the 2 nd current value larger than the 1 st current value, thereby increasing the amount of heat generation of the heater unit 80. This enables the heater unit 80 to be downsized, and therefore, the entire refrigerator 1 can be downsized.

While the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments. For example, a plurality of heater units for heating the cooler 20 may be provided. For example, the refrigerator 1 is provided with two heater units. In this case, as shown in fig. 11, the heater driving device 2100 may selectively drive the two heater units 281, 282. Each of the heater units 281 and 282 has a lower heater disposed below the cooler 20 and a side heater disposed on a side of the cooler 20. Here, the heater control portion 2114 controls the current supply portion 2105 in the normal mode so that the 1 st state in which current is supplied to only one heater unit 281 is achieved. When increasing the amount of heat generated by the entire two heater units 281 and 282, the heater controller 2114 controls the current supplier 2105 to change from the 1 st state to the 2 nd state in which current is supplied to both the two heater units 281 and 282. The number of the heater units 80 is not limited to two, and may be three or more.

According to this configuration, since it is only necessary to select and switch the heater unit 80 to be the current supply destination of the current supply unit 2105, the configuration of the power conversion circuit included in the current supply unit 2105 can be simplified, thereby simplifying the configuration of the entire current supply unit 2105.

In the embodiment, an example is described in which the heater controller 114 controls the current supplier 105 such that the supply of current from the current supplier 105 to the heater unit 80 is stopped when the measured temperature of the cooler 20 reaches the upper limit management temperature. However, the condition for stopping the supply of current from the current supply unit 105 to the heater unit 80 is not limited to the measured temperature of the cooler 20 being equal to or higher than the upper limit management temperature. For example, as shown in fig. 12, refrigerator 1 includes temperature measuring devices 390, 391, 392, 393, and 394 provided in refrigerating compartment 10, ice making compartment 11, switching compartment 12, vegetable compartment 13, and freezing compartment 14, respectively. These temperature measuring devices 390, 391, 392, 393, and 394 correspond to the 2 nd temperature measuring device described in the claims. In this case, when all of the temperatures measured by temperature measuring devices 390, 391, 392, 393, and 394 are equal to or higher than the storage room upper limit management temperature set in advance, heater controller 114 may control current supply unit 105 so as to stop the supply of current from current supply unit 105 to heater unit 80. Alternatively, when at least one of the temperatures measured by the temperature measuring devices 390, 391, 392, 393, and 394 is equal to or higher than the storage room upper limit management temperature set in advance, the heater controller 114 may control the current supplier 105 so as to stop the supply of the current from the current supplier 105 to the heater unit 80.

According to this configuration, since the temperature rise in the storage chamber is suppressed, the quality of the food stored in the storage chamber can be prevented from being lowered.

In the embodiment, an example has been described in which the heater driving device 100 ends the heater driving process in any of a case where the elapsed time after the start of the supply of the electric current to the heater unit 80 is equal to or longer than the heater driving time, and a case where the measured temperature of the cooler 20 is equal to or higher than the upper limit management temperature. However, the heater driving device 100 is not limited to this, and may end the heater driving process only when, for example, an elapsed time after the start of the supply of electric current to the heater unit 80 is equal to or longer than a heater driving time or only when the measured temperature of the cooler 20 is equal to or higher than the upper limit management temperature. Alternatively, the heater driving device 100 may end the heater driving process when, for example, the elapsed time after the start of the current supply to the heater unit 80 is equal to or longer than the heater driving time and the measured temperature of the cooler 20 is equal to or higher than the upper limit management temperature.

In the embodiment, an example has been described in which, when the duration of a state in which the absolute value of the temperature difference between the measured temperature of the cooler 20 and the melting point of ice is equal to or less than the reference temperature difference is equal to or longer than the reference time, the setting unit 115 updates the upper limit management temperature to a high temperature and the heater driving time to a time longer than a preset time. However, the present invention is not limited to this, and the setting unit 115 may set the heater driving time to be longer than a preset time when the above-described duration is equal to or longer than the reference time. Alternatively, when the above-described duration is equal to or longer than the reference time, the setting unit 115 may update only the upper limit management temperature to a higher temperature without changing the heater driving time, or may update only the heater driving time without changing the upper limit management temperature to a longer time.

In the embodiment, an example in which the temperature measuring instrument 90 is disposed in the header part 21a is described, but the position of the temperature measuring instrument 90 is not limited to this. For example, the temperature measuring device 90 may be disposed in a portion other than the header portion 21a in the cooler 20. In this case, the determination temperature corresponding to the measured temperature of the cooler 20 when the frost adhering to the cooler 20 melts can be a temperature higher than the melting point of ice. In this case, the determination temperature may be set to a temperature higher than the melting point (0 ℃) of ice by a predetermined temperature.

In the embodiment, the example in which the temperature measuring device 90 is a temperature measuring device having a thermistor has been described, but for example, the temperature measuring device 90 may have a pressure detector that detects the pressure in the cooler refrigerant pipe 21 and a temperature calculator that calculates the temperature of the refrigerant corresponding to the pressure value based on the pressure value detected by the pressure detector. In this case, the determination temperature is the temperature of the refrigerant corresponding to the pressure value detected by the pressure detector, and the information indicating the reference temperature difference stored in the reference DB131 may be information indicating the temperature that is the reference of the absolute value of the temperature difference from the evaporation temperature of the refrigerant when all of the refrigerant evaporates in the cooler 20. In this case, in step S106 of the heater driving process, the determination unit 113 may determine whether or not the absolute value of the temperature difference between the determination temperature and the evaporation temperature is equal to or less than the reference temperature difference.

In the embodiment, the example in which the lower heater 80A and the side heater 80B are each a so-called carbon heater has been described, but the types of the lower heater 80A and the side heater 80B are not limited thereto. For example, the lower heater 80A and the side heater 80B may be so-called nichrome heaters having nichrome wires, or may be heaters having black bodies that emit infrared rays or far infrared rays other than carbon fibers. The shapes of the lower heater 80A and the side heater 80B are not limited to the linear and meandering shapes described above, and may be other shapes according to the shape of the cooler 20. The arrangement of the heater unit 80 is not limited to the arrangement described in the embodiment, and other arrangements may be adopted as long as the cooler 20 can be heated.