JP2005140414A - Freezing and refrigerating unit, and refrigerator using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent failure of a compressor by driving the compressor at low speed since a pressure of the compressor rises when a fan cooling the compressor stops due to anomaly. <P>SOLUTION: Since a plurality of condenser fans 6a and 6b are provided, and parallel connection of each fan to the same power source is carried out, even when one fan stops due to anomaly, by driving the other fan at the maximum rotational frequency, temperature rise of heat exchange of a condenser is suppressed, and since abnormal rise of condensing temperature can be suppressed, failure of the compressor can be prevented. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a refrigeration unit and a refrigerator using the same, and particularly to a commercial large refrigerator.

  In recent years, people's awareness of global environment protection is very high, and there is a strong demand for reducing the power consumption of home appliances. Under such circumstances, reduction of power consumption in refrigerators is one of the very important technologies, and most of refrigerators used in general households are compressors and DC fan motors that employ DC brushless motors. Is adopted. Even in commercial refrigerators mainly used in restaurants, etc., power consumption reduction technology is a very important technology, but when an abnormality occurs in the refrigerator, how to keep the refrigerator inside in a cooled state, Equally important technology is the ability to hold food stored in large quantities.

  As a conventional refrigerator control device, there is one that prevents a compressor failure by driving the compressor at a low speed when a compressor cooling fan fails (see, for example, Patent Document 1).

  The conventional refrigerator control device will be described below with reference to the drawings. The compressor 101 includes a compressor 101 capable of changing the number of revolutions and a compressor blower 102 for cooling the compressor 101. The compressor 101 is driven by a compressor driving means 103. Based on the signal detected by the internal temperature sensor 104, the internal temperature detection means 105 detects the temperature, and the internal temperature determination means 106 determines whether the internal temperature is higher or lower than the set temperature. When it is high, the compressor 101 is driven, and when it is low, the compressor 101 is stopped.

  Further, at this time, the outside air temperature detecting means 108 detects the outside air temperature based on the signal detected by the outside air temperature sensor 107, and the outside air temperature judging means 109 detects the outside air temperature higher than the preset outside air temperature and the inside temperature. When it is determined by the determination means that the internal temperature is high, the compressor blower control means 110 outputs a command to drive the compressor blower to the compressor blower drive means 111, whereby the compressor blower 102. Drive.

In addition, a rotation detection unit 112 is provided to detect the operating state of the compressor blower 102, and the rotation detection unit 113 determines whether the state detected by the rotation detection unit 112 has been rotated or stopped. The compressor control means 114 controls the operating state of the compressor 101 by the internal temperature determination means 106 and the rotation determination means 113, and it is determined that the outside air temperature and the internal temperature are higher than the set temperature. If it is determined that the compressor blower is stopped regardless of the situation to be driven, the compressor rotating means 115 is used to drive the compressor 101 at a low speed.
JP-A-8-271109

  However, in the above conventional configuration, since there is only one fan for cooling the compressor, when the fan is stopped due to an abnormality, the compressor is driven at a low speed, and the abnormality is detected and used. However, an increase in the condensation temperature of the refrigerant is unavoidable, and the suction pressure of the compressor increases. At this time, if the compressor is driven at a low speed, the compressor may stop due to step-out, and accordingly, there is a problem that the temperature inside the refrigerator rises.

Another object of the present invention is to prevent a compressor failure by suppressing a rise in the temperature of the refrigerator and a rise in the temperature of the condenser even when there is an abnormality in the fan motor that cools the condenser. The purpose is to do.

  According to the present invention, in a refrigerator having a plurality of condenser fans whose DC power source is a power source and the number of revolutions can be changed by an applied voltage, each condenser fan is connected in parallel to the same power source. Since the other condenser fans are normal even when stopped, driving the fans can dissipate heat from the condenser and prevent the compressor temperature from rising due to abnormal condenser temperature rise. So you can prevent compressor failure.

  The present invention provides a cooling system having a plurality of condenser fans whose rotational speed can be varied by applying a DC power source, and each condenser fan is connected in parallel to the same power source. Even if an abnormality occurs and the compressor is stopped, it is possible to dissipate heat from the condenser by driving another condenser fan, so that the compressor temperature rise due to the abnormal temperature rise of the condenser can be suppressed, and the compressor malfunctions. Can be prevented.

  The invention according to claim 1 of the present invention is a refrigerator having a plurality of condenser fans whose power source is a DC power source and the number of revolutions of which can be changed by an applied voltage. Each condenser fan is connected in parallel to the same power source. Even if one condenser fan is abnormal and stopped, the other condenser fans are normal. By driving that fan, the heat can be dissipated by the condenser, and the abnormal temperature rise of the condenser Compressor temperature rise can be prevented, so that compressor failure can be prevented.

  According to a second aspect of the invention, in the first aspect of the invention, when one of the condenser fans is stopped due to an abnormality, the other condenser fans are normally driven. Since the DC power supply can be used, even if one condenser fan is locked and the current increases, the output voltage of the DC power supply does not drop below the specified voltage. Therefore, it is possible to prevent an increase in the temperature of the compressor due to an abnormal increase in the temperature of the condenser. Therefore, it is possible to prevent the compressor from being broken.

  The invention according to claim 3 has the condenser fan abnormal stop detection means in the invention according to claim 1 or 2, and detects that at least one condenser fan is in a stopped state due to an abnormality. In this case, the output of the condenser fan in an abnormal state is stopped and only the other condenser fan is driven, so the output capacity of the DC power supply can be reduced, and the DC power supply can be reduced in size and cost. it can.

  According to a fourth aspect of the present invention, in the first to third aspects of the invention, when it is detected that at least one condenser fan is in a stopped state due to an abnormality, the output of the condenser fan that is in an abnormal state Is stopped and the remaining condenser fan is driven at the maximum speed, so the normal condenser fan can compensate for the decrease in airflow due to the stopping of one condenser fan, so the rise in the temperature of the condenser can be suppressed. The temperature of the machine can be further prevented and the compressor can be prevented from malfunctioning.

  The invention according to claim 5 has the compressor according to claim 1 to the invention according to claims 1 to 4, a compressor capable of varying the driving rotational speed, and a condensation temperature detector that is installed in the condenser and detects the condensation temperature, If it detects that at least one condenser fan is stopped due to an abnormality, it limits the upper limit of the compressor drive speed, so if one or more condenser fans fail, By limiting, it is possible to avoid further increasing the condenser temperature, so that it is possible to prevent a compressor failure due to an increase in the compressor temperature.

  According to a sixth aspect of the present invention, in the first to fifth aspects of the invention, when it is detected that at least one condenser fan is stopped due to an abnormality, the condensation temperature is equal to or higher than a certain temperature. Since the lower limit value of the drive speed of the compressor is limited, when the compressor is driven at a low speed while the condenser temperature is high, the compressor is prevented from stopping due to out-of-step. An increase in internal temperature can be prevented.

  According to the seventh aspect of the present invention, since the condenser fan abnormality can be detected by the inclination of the temperature rise of the condensing temperature detector in the first to sixth aspects of the invention, a stop detection function is provided for the condenser fan. It is not necessary to use a fan having a power supply, or to provide a stop detection circuit such as a current detection circuit or a stop detection circuit, so that the cost can be reduced.

  The invention according to claim 8 has the display means in the invention according to claims 1 to 7, and when an abnormality of the condenser fan is detected, an abnormal fan is identified and a warning is displayed. Therefore, since the user can quickly confirm that an abnormality has occurred, it is possible to promptly respond to a repair request or the like. In addition, since the repair person can immediately identify the fan with an abnormality, the repair time can be shortened and the maintainability can be improved.

  The invention according to claim 9 is the one in which the refrigeration unit according to any one of claims 1 to 8 is provided in the upper part of the refrigerator main body, and HC refrigerant is used as the refrigerant. Therefore, it is possible to ensure reliability even for a refrigerator when using a refrigerant that is high and it is difficult to ensure the durability of the compressor.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a refrigerator-freezer unit and a refrigerator using the same according to the present invention will be described below with reference to the drawings. In addition, about the same structure as the past, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.

(Embodiment 1)
FIG. 1 is a schematic diagram of a refrigeration unit according to the present invention and a cooling system of a refrigerator using the same, and FIG. 2 is a block diagram of the refrigeration unit of the embodiment and a refrigerator using the same.

  In FIG. 1, the cooling system of the present invention includes an inverter compressor 1 using a brushless DC motor that compresses a gaseous refrigerant of, for example, R600a with a hydrocarbon refrigerant (HC refrigerant) and a gaseous refrigerant. The condenser 2 for condensing the liquid, the decompressor 3 for reducing the pressure of the liquid refrigerant, and the evaporator 5 for cooling the storage chamber 4 for storing the food in the refrigerator by evaporating the liquid refrigerant.

  The condenser 2 cools the high-temperature gas refrigerant sent from the compressor 1 by two condenser fans 6a and 6b, thereby accelerating the condensation of the refrigerant. Further, in the vicinity of the evaporator 5, two evaporator fans 7a and 7b are provided in order to circulate the air cooled by the heat of vaporization taken away when the refrigerant evaporates into the storage chamber. The condenser fans 6a and 6b and the evaporator fans 7a and 7b employ DC motors that can vary the number of rotations according to the applied voltage.

  In this embodiment, two condenser fans and two evaporator fans are provided, but three or more condenser fans and evaporator fans may be provided. The condensation temperature detector 8 is installed in contact with the condenser 2 and detects the condensation temperature of the refrigerant. When the condensation temperature is higher than a set value, the maximum rotation speed and the minimum rotation speed of the compressor 1 are detected. By limiting, it is provided to prevent the failure of the compressor.

The internal temperature detector 9 is installed in the storage room 4 for storing food in the refrigerator, and compares the temperature of the storage room 4 with the set temperature of the storage room, so that the compressor is operated or stopped and operated. Is provided for setting the drive rotational speed of the motor. As shown in FIG. 3, the condensation temperature detector 8 and the internal temperature detector 9 are composed of a temperature detection thermistor and a fixed resistor connected in series, and a voltage divided by the resistance and the fixed resistance of the thermistor. Is output.

  Next, in FIG. 2, a DC power source 10 is a power source for driving the condenser fans 6a and 6b. This power supply has an output voltage of DC12V ± 5%. The DC power supply 10 is configured such that when the connected condenser fan is incorporated in the cooling unit, the maximum current during normal operation with DC12V input is 200 mA, and the maximum current in the locked state is 400 mA, the DC power supply The output current capacity is designed so that a DC power supply output of 12V ± 5% can be secured even when one condenser fan is driven normally and one is locked (total output current 600mA). .

  In this embodiment, only the condenser fan is connected to the power source, but the evaporator fans 7a and 7b may also be connected. However, in this case, the DC power supply should be designed so that a predetermined voltage can be secured even if the fan with the maximum output current is locked. In the present embodiment, the output voltage of the DC power supply 10 is 12V, but any voltage such as 15V or 24V that matches the fan specifications may be used.

  The internal temperature detection means 11 and the condensation temperature detection means 12 detect the internal temperature or the condensation temperature by A / D converting the output voltages from the internal temperature detector 9 and the condensation temperature detector 8, respectively. It is. The condenser fan drive means 13a, 13b converts the voltage supplied from the DC power supply 10 into a predetermined voltage based on the command voltage for driving the condenser fans 6a, 6b received from the control unit 14 or the driving rotational speed of the fan. Then, it is supplied to the condenser fans 6a and 6b.

  The compressor drive means 15 receives the drive rotation speed command (0 r / s command at the time of stop) of the compressor 1 from the control unit 14 and drives the compressor 1 at the command rotation speed. In addition, while the drive rotation speed of the compressor 1 by the control part 14 is determined based on the internal temperature detected by the internal temperature detector 9, and the preset temperature of the storage chamber 4 preset by the control part 14, The maximum rotation speed and the minimum rotation speed are limited by the condensation temperature detected by the condensation temperature detector 8.

  Further, the drive rotation speed or drive voltage of the condenser fans 6 a and 6 b is determined by the drive rotation speed of the compressor 1 and the detected temperature of the condensation temperature detector 8. The display means 16 is for receiving a display command from the control unit 14 to display a set temperature of the storage room, a current room temperature of the storage room, or a warning when an abnormality is detected.

  The operation of the refrigeration unit configured as described above and a refrigerator using the same will be described. First, the drive state of the compressor 1 is determined based on the set temperature of the storage room preset in the control unit 14 and the internal temperature detected by the internal temperature detector 9 to determine the operation speed of the compressor 1. (For example, when the initial rotation speed at the time of starting the compressor is 40 r / s and the internal temperature is higher than the set temperature by 1 ° C. or more, the compressor rotation speed is increased by 10 r / s every 5 minutes.

  When the internal temperature is higher than the set temperature by 0 ° C or more and less than 1 ° C, the compressor speed is decreased by 10 r / s every 5 minutes. If the internal temperature becomes lower than the set temperature, 0r / s command). If the internal temperature is higher than the set temperature, the compressor speed is increased to increase the cooling rate when the internal temperature rises. When the internal temperature is close to the set temperature, the energy saving operation can be performed by driving the compressor 1 at a low speed.

FIG. 4 shows the relationship between the evaporation (inside chamber) temperature and the condensation temperature in the compressor usage range, and the shaded area is the compressor usage range. As shown in FIG. 4, when the evaporation (inside chamber) temperature is high (Tj or more), the condensation temperature is allowed up to Tg, and the evaporation (inside chamber) temperature is low (T
In the case of less than g), the condensation temperature must be kept lower than Tg.

  Therefore, when the compressor is driven, while monitoring the internal temperature and the condensation temperature, when the condensing temperature with respect to the internal temperature approaches or reaches the upper limit temperature of the compressor using range, the rotational speed of the compressor 1 is set. The failure of the compressor 1 is prevented by lowering and suppressing the rise in the condensation temperature. The compressor is driven or stopped by the compressor driving means 15 according to the command rotational speed of the compressor 1 thus determined.

  The determination of the driving state of the condenser fans 6 a and 6 b is driven or stopped in synchronization with the driving or stopping of the compressor 1. During the driving of the compressor, the voltage to be driven is determined by the temperature detected by the condensation temperature detector 8 (for example, the driving voltage is 8 V when the condensation temperature is less than 30 ° C., and the condensation temperature is 30 ° C. or less than 40 ° C.) 10. When the condensation temperature exceeds 40 ° C., the drive voltage is increased and the condenser fan is driven at a higher speed by increasing the condensation temperature. The failure is prevented.

  Further, since the condenser fans 6a and 6b are connected in parallel to the DC power source 10, the remaining fans can be driven even when one condenser fan is stopped due to disconnection or the like. The DC power supply 10 has an output current capacity that can stably supply a specified voltage (12 V ± 5% in this embodiment) even when one of the two condenser fans is locked. Therefore, even if the condenser fan 6a is now locked, the condenser fan 6b can be driven at a predetermined voltage and a predetermined rotation speed.

  Therefore, even if one of the condenser fans is in a stopped state due to a disconnection or a locked state, the condenser fan 6b can be driven stably at a predetermined voltage and rotation speed, and thus an abnormal temperature rise of the condenser can be suppressed. In addition, the command rotation speed of the compressor at this time detects the rise in the condenser temperature due to the stop of the condenser fan 6a, and limits the maximum rotation speed of the compressor, thereby preventing the compressor from being damaged and further compressing. By limiting the lower limit rotational speed of the machine, the temperature rise in the storage chamber is prevented by preventing the stop of the step-out due to the low-speed drive of the compressor when the condensation temperature is high and the compressor suction pressure is high.

  Further, the control unit 14 calculates the inclination of the rise of the condensation temperature detected by the condensation temperature detector 8 when the compressor is driven, and when the inclination exceeds a certain inclination, the heat dissipation of the condenser is not promoted, and the condenser The refrigerant condensing start position is shifted from the condenser inlet to the outlet and the condensing temperature detector detects the discharge gas temperature of the high-temperature compressor, so that at least the condenser fans 6a and 6b It can be indirectly detected that one has stopped due to an abnormality.

  At this time, by issuing an abnormality warning by the display means 16, the user can quickly recognize the abnormality, so that it is possible to prevent a failure due to a rise in the compressor temperature accompanying a rise in the condenser temperature by an immediate response such as a repair request. It becomes.

(Embodiment 2)
FIG. 5 is a block diagram of a refrigeration unit and a refrigerator using the same according to Embodiment 2 of the present invention.

  In FIG. 5, condenser fan abnormality detection means 17a, 17b detects whether each fan is normally driven or stopped due to an abnormality. As a detection method, the fan current is detected and preset. This is realized by comparing whether the current value is within the upper and lower limits. Further, if the fan itself has an abnormal output function, the abnormal state can be easily detected by the output signal.

  Further, the driving speed or driving voltage of the condenser fans 6a and 6b includes the driving speed of the compressor 1, the detected temperature of the condensing temperature detector 8, and the condenser fans 6a and 6b by the condenser fan abnormality detecting means 17a and 17b. It is determined by the driving state. In the present embodiment, condenser fan abnormality detecting means 17a and 17b are further provided in the refrigeration unit and the refrigerator using the same according to the first embodiment.

  The operation of the refrigeration unit configured as described above and a refrigerator using the same will be described below.

  In the second embodiment, since the condenser fan can detect an abnormal stop due to disconnection or lock, when the abnormality is detected, the output current capacity of the DC power supply 10 is 2 by stopping the output of the corresponding fan. The total when one condenser fan is driven at the maximum rotation (in this embodiment, the number of rotations when DC 12 V is applied) (for example, the output current of each fan at the time of 12 V input is 200 mA, the output capacity is 400 mA).

  Therefore, it is possible to suppress the output capacity of the DC power supply, and the power supply can be reduced in size and cost.

  Now, when the condenser fan driving means 13a, 13b is applied with 8V as the driving voltage of the condenser fans 6a, 6b, the output of the condenser fan 6a is stopped when the abnormality of the condenser fan 6a is detected. Since the condenser fan 6b is in a driving state, it is possible to suppress the temperature rise of the compressor accompanying the rapid temperature rise of the condenser, and it is possible to prevent a compressor failure.

  Further, at this time, the condenser fan 6b is driven at the maximum voltage (12V in the present embodiment) by the condenser fan driving means 13b, so that the air flow shortaged when the condenser fan 6a is stopped is driven at a high speed by the condenser fan 6b. This can be compensated for, and the temperature rise of the compressor due to the temperature rise of the condenser can be further suppressed.

  In addition, at this time, when the condensation temperature with respect to the internal temperature approaches or reaches the upper limit temperature range of the compressor due to the relationship between the evaporation (internal) temperature and the condensation temperature shown in FIG. The upper limit number of rotations of the compressor 1 is limited so as not to increase further, the increase in the condensation temperature is limited, and a compressor failure is prevented. At the same time, by limiting the lower limit rotation speed of the compressor, it is possible to prevent the internal temperature from rising due to stoppage due to step-out when the compressor is driven at low speed when the condensation temperature is high and the compressor suction pressure is high. ing.

  Next, the display means will be described. When it is detected that the condenser fans 6a and 6b are abnormally stopped by the condenser fan abnormality detecting means, the display of the temperature in the storage chamber or the set temperature of the storage chamber that has been displayed so far is stopped, The control means 14 instructs the display means 16 to perform a warning display that identifies the condenser fan that is in an abnormally stopped state, and the display means 16 issues an abnormal warning display according to the instruction.

  Thereby, since the user of the refrigerator can recognize that the condenser fan is in an abnormal state, a quick response such as a repair request becomes possible. Furthermore, by identifying the condenser fan in an abnormal state, it is possible to tell which fan has failed when requesting a repair. In addition, since the repair person can easily identify the failed fan, the repair time can be shortened and a smooth response can be achieved.

  The abnormality warning display may not be an abnormality display specifying the condenser fan in the abnormal state, but may be a display in which any of the condenser fans is in the abnormal state.

  As described above, according to the present invention, since a plurality of condenser fans are connected in parallel to the same power source, even if an abnormality occurs in one condenser fan, heat is released from the condenser by driving another condenser fan. Therefore, it is possible to prevent a compressor failure due to an abnormal temperature rise of the condenser, and it can be applied to the technical field of refrigeration air conditioning equipment.

Schematic diagram of cooling system according to Embodiment 1 of the present invention Block diagram of the embodiment Configuration diagram of the temperature detector of the same embodiment Characteristics diagram of compressor usage range of the same embodiment Block diagram of Embodiment 2 of the present invention Electric circuit diagram of conventional refrigerator abnormality detection device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compressor 2 Condenser 6a, 6b Condenser fan 8 Condensing temperature detector 10 DC power supply 16 Display means 17a, 17b Condenser fan abnormality detection means

Claims (9)

  A refrigerator having a plurality of condenser fans, each of which has a DC power source as a power source and the number of revolutions of which can be varied by an applied voltage, wherein each condenser fan is connected in parallel to the same power source.   2. The refrigeration refrigerator according to claim 1, further comprising: a DC power source capable of normally driving another condenser fan when one of the condenser fans is stopped due to an abnormality. 5. unit.   When the condenser fan abnormal stop detection means is provided and it is detected that at least one condenser fan is in a stopped state due to an abnormality, the output of the condenser fan in an abnormal state is stopped, and only the other condenser fans are The refrigeration unit according to claim 1 or 2 to be driven.   When it is detected that at least one condenser fan is in a stopped state due to an abnormality, the output of the condenser fan in an abnormal state is stopped, and the remaining condenser fans are driven at a maximum rotational speed. The refrigeration unit according to any one of claims 1 to 3.   A compressor with a variable drive speed and a condensation temperature detector that is installed in the condenser and detects the condensation temperature. When it is detected that at least one condenser fan is stopped due to an abnormality, the condensation temperature is The refrigeration unit according to any one of claims 1 to 4, wherein when the temperature is equal to or higher than a certain temperature, an upper limit value of a driving rotational speed of the compressor is limited.   The lower limit value of the drive rotational speed of the compressor is limited when the condensation temperature is equal to or higher than a certain temperature when it is detected that at least one condenser fan is stopped due to an abnormality. The refrigeration unit according to any one of claims 5 to 6.   The refrigeration unit according to any one of claims 1 to 6, wherein an abnormality of the condenser fan is detected based on an inclination of a temperature rise of the condensation temperature detector.   8. The refrigerator-freezer according to claim 1, further comprising a display unit that, when detecting an abnormality of the condenser fan, identifies an abnormal fan and displays a warning. 9. unit.   A refrigerator comprising the refrigeration unit according to any one of claims 1 to 8 in an upper part of a refrigerator body and using HC refrigerant as a refrigerant.

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