JP2016061520A - Refrigeration storage house and method for controlling the number of rotation of compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigeration storage house capable of shortening a cooling time up to a set temperature in the case that a compressor is variably controlled for its number of rotation in response to a difference between an in-storage temperature and a set temperature.SOLUTION: A revolution control part for a refrigeration storage device performs a determination processing [S50] for determining whether or not an accumulated time of a period in which an in-house temperature TH is more than a prescribed temperature PD that is a higher temperature than a set temperature SP that is a target refrigeration temperature reaches a prescribed value [a count=2]; and a revolution number fixing processing [S60] for fixing a revolution number of an inverter motor to a high revolution number [90/s] near the highest revolution number at least until the in-house temperature TH reaches up to the set temperature SP when it is determined in the determination processing that the accumulated time reaches up to the prescribed value [S50:YES].SELECTED DRAWING: Figure 4

Description

  The present invention relates to a cooling storage for driving a compressor by an inverter motor and a method for controlling the rotational speed of the compressor.

  2. Description of the Related Art In recent years, for example, commercial refrigerators that are equipped with an inverter compressor that is driven by an inverter motor and that can control the rotation speed are becoming widespread (see, for example, Patent Document 1).

  Although there are various advantages provided with the inverter compressor, an example is an increase in efficiency during the control cooling operation. This is because when the control cooling operation is performed to maintain the interior at the set target temperature, when the interior temperature approaches the set temperature that is the target temperature for cooling, the speed of the inverter compressor (the number of revolutions) ) In a stepwise manner. When this control method is adopted, the continuous on-time of the compressor is overwhelmingly long. In other words, the number of on / off switching operations is greatly reduced, and high efficiency and energy saving are achieved.

JP 2002-195719 A

  However, the conventional control method obtains the deviation between the internal temperature and the set temperature at regular intervals, and when the deviation is large, the rotational speed is increased, and when the deviation is small, the rotational speed is decreased. It has the disadvantage that it takes time unnecessarily to reach the set temperature. For example, if the door is repeatedly opened and closed temporarily during controlled cooling operation where the inside of the cabinet is maintained near the set temperature suitable for cooling food, the inside temperature will suddenly rise rapidly. There appears a time when the deviation from the temperature temporarily increases. In such a case, the internal temperature suddenly rises, and initially the maximum rotational speed can be generated, but the rotational speed decreases as the internal temperature decreases and approaches the set temperature. It takes longer to reach the temperature. For this reason, there is a disadvantage that it is not possible to respond to the request to cool quickly.

  Therefore, in the present specification, in the case where the compressor is variably controlled in accordance with the deviation between the internal temperature and the set temperature, the cooling storage that can shorten the cooling time to the set temperature, and the rotational speed control method for the compressor Is to provide.

The cooling storage disclosed by the present specification includes a compressor driven by an inverter motor, a condenser that dissipates heat from the refrigerant compressed by the compressor, and a cooler that is supplied with refrigerant from the condenser through a throttling device. A storage room having a storage room in which the storage room is cooled by cold air generated by the cooler, a temperature sensor for detecting the internal temperature of the storage room, and the internal temperature is a cooling target. A timer that measures the accumulated time during a period that is equal to or higher than a predetermined temperature that is higher than a set temperature that is a temperature to be set, and the number of revolutions of the inverter motor is variable in accordance with a deviation between the internal temperature and the set temperature A rotation speed control unit that executes a rotation speed variable process, wherein the rotation speed control unit determines whether or not the accumulated time has reached a predetermined value, and the determination process When it is determined that the accumulated time has reached the predetermined value, the rotational speed of the inverter motor is fixed at a high rotational speed near the maximum rotational speed until at least the internal temperature reaches the set temperature. And processing.
According to this configuration, when the accumulated time of the period in which the internal temperature is equal to or higher than the predetermined temperature is equal to or higher than the predetermined temperature, the rotation speed of the inverter motor is at least until the internal temperature reaches the predetermined temperature. It is fixed at a high speed near the maximum speed. Thereby, in the case where the rotational speed of the compressor is controlled according to the deviation between the internal temperature and the set temperature, the cooling time to the set temperature can be shortened. Here, the “high rotation speed in the vicinity of the maximum rotation speed” includes a rotation speed in a range from the rotation speed corresponding to 85% of the maximum rotation speed to the maximum rotation speed. In addition, when the inverter motor speed is controlled in steps from the lowest speed to the highest speed, the speed corresponding to the speed of the highest speed several steps is set to the “highest speed” according to the number of stages. It is included in the “high rotation speed near the number”. For example, when step control is performed in 12 stages from 0th speed to 11th speed, the rotation speeds corresponding to the 9th speed, the 10th speed, and the 11th speed are included in the “high rotation speed near the maximum rotation speed”.

The cooling storage unit includes a counter, the rotation speed control unit samples the internal temperature from the temperature sensor at a predetermined sampling interval, the timer measures the sampling interval, and the counter The rotational speed control unit counts the number of samplings for sampling the internal temperature during a period in which the internal temperature is equal to or higher than the predetermined temperature, and the rotational speed control unit determines that the sampling number is a predetermined number of times in the determination process. If it has reached, it may be determined that the accumulated time has reached the predetermined value.
According to this configuration, the integration time is determined to have reached a predetermined number of times of sampling the internal temperature. In other words, the integrated time, which is a condition for determining whether or not the rotational speed of the inverter motor is fixed to a high rotational speed near the maximum rotational speed, is not set as the integrated value of the time itself, and the internal temperature is set as a sampling interval (section) unit. As a result, the determination can be simplified, and thereby the rotational speed control of the inverter motor can be simplified.

In the cooling storage, the rotation speed control unit may execute the rotation speed variable process when the sampling number does not reach the predetermined number.
According to this configuration, in a period in which the number of times of sampling does not reach the predetermined number of times when the internal temperature rises to a predetermined temperature or higher due to the opening and closing of the door normally performed during the so-called control cooling operation for cooling the stored items. While executing the rotation speed variable process, the rotation speed fixing process can be suitably executed when the door is frequently opened and closed.

  Further, the compressor rotational speed control method disclosed in the present specification includes a compressor driven by an inverter motor, a condenser for releasing heat from the refrigerant compressed by the compressor, and a refrigerant from the condenser is throttled. A method for controlling the number of revolutions of a compressor of a cold storage comprising a cooler supplied through the apparatus, and a storage chamber having a storage chamber, wherein the storage chamber is cooled by cold air generated by the cooler, A detection step for detecting the internal temperature in the storage chamber, and a rotational speed variable step for changing the rotational speed of the inverter motor according to a deviation between the internal temperature and a set temperature that is a target temperature for cooling. A measuring step for measuring an integrated time in a period in which the internal temperature is equal to or higher than a predetermined temperature that is higher than the set temperature, and a determining step for determining whether or not the integrated time has reached a predetermined value. , When it is determined in the determination step that the accumulated time has reached the predetermined value, the rotation speed of the inverter motor is set to a high rotation speed near the maximum rotation speed until at least the internal temperature reaches the set temperature. A rotational speed fixing step of fixing.

  In the compressor rotation speed control method, in the detection step, the internal temperature is sampled at a predetermined sampling interval, and in the measurement step, the internal temperature is in a period during which the internal temperature is equal to or higher than the predetermined temperature. The number of samplings for sampling the temperature may be counted, and when the number of samplings reaches a predetermined number in the determination step, it may be determined that the integration time has reached the predetermined value.

  In the compressor rotation speed control method, the rotation speed variable step may be performed when the sampling count does not reach the predetermined count.

  According to the cooling storage and the rotation speed control method of the compressor disclosed in the specification, when the accumulated time of the period in which the internal temperature is equal to or higher than the predetermined temperature is equal to or higher than the predetermined temperature, The rotational speed is fixed at a high rotational speed in the vicinity of the maximum rotational speed until at least the internal temperature reaches the set temperature. Thereby, in the case where the compressor is variably controlled according to the deviation between the internal temperature and the set temperature, the cooling time to the set temperature can be shortened.

Sectional drawing of the cooling storage which concerns on one Embodiment Configuration diagram of cooling cycle of cooling storage Explanatory drawing which shows the example of the relationship between internal temperature and rotation speed Schematic flowchart showing compressor speed control processing Schematic time chart showing transition of internal temperature and rotation speed during pull-down cooling operation Schematic time chart showing transition of internal temperature and rotation speed during control cooling operation

<Embodiment>
One embodiment will be described with reference to FIGS.
1. Configuration of Cooling Storage In this embodiment, the case of a commercial vertical refrigerator is illustrated as a cooling storage, and the overall structure will be described first with reference to FIG. The vertical refrigerator is composed of a vertically insulated heat insulating storage 10 with a front opening, and is supported by legs 11 standing at the four corners of the lower surface, and the inside is a refrigerating room 12 which is a storage room. A front opening of the refrigerator compartment 12 is partitioned into two upper and lower openings 14 by a partition frame 13, and a heat insulating door 15 is attached to each opening 14 so as to be swingable in a horizontal direction.

  On the upper surface of the heat insulating storage 10, a machine room 18 is provided surrounded by a panel 17, and a refrigeration unit 20 installed on a base 19 is accommodated therein. As shown in FIG. 2, the refrigeration unit 20 includes a compressor 22, a condenser 24, a dryer 25, a capillary tube 26, a cooler 27, and an accumulator 28.

  The compressor 22 is driven by the inverter motor 21 to compress the refrigerant. The condenser 24 is cooled by the condenser fan 23. The capillary tube 26 corresponds to a throttling device. The cooler 27 evaporates the refrigerant that has passed through the capillary tube 26.

  Each device is circulated and connected by a refrigerant pipe 29. As shown in FIG. 1, the base 19 is attached so as to close the window hole 16 formed in the ceiling wall of the refrigerator compartment 12.

  A drain pan 30 that also serves as an air duct is stretched on the lower surface side of the window hole 16 in the ceiling portion of the refrigerator compartment 12, and a cooler chamber 31 is formed above the drain pan 30. The bottom surface of the drain pan 30 is formed to have a downward slope toward the rear edge (left side in FIG. 1), and a blowout port 33 is cut out on the rear edge side. In addition, a suction port 32 is opened in a region on the front side of the drain pan 30, and the air in the refrigerator compartment 12 is sucked by a fan 34 provided on the upper side of the drain pan 30 and cooled by a cooler 27 to be blown out. 33 is returned to the refrigerator compartment 12. In the cooler chamber 31, a temperature sensor 35 for detecting the internal temperature TH, which is the temperature in the refrigerator compartment 12, is provided at a position where the internal air flowing in from the suction port 32 comes into contact.

  As shown in FIG. 2, the inverter motor 21 is driven by an inverter drive circuit 36 that outputs AC power having a variable frequency, and the output frequency is determined by the control unit 40. The inverter motor 21 is, for example, a three-phase four-pole motor.

  The control unit 40 includes a CPU (an example of a rotation speed control unit) 41, a temperature setting unit 42, a memory 43, a timer 44, a counter 45, and the like. The configuration of the control unit 40 is not limited to this, and the control unit 40 may be configured by an ASIC (specific application IC) including a CPU or the like.

  The temperature setting unit 42 sets a set temperature SP that is a target temperature for cooling in the refrigerator compartment 12. Here, the set temperature SP includes a set temperature set by the user via the temperature setting unit 42 and a set temperature stored in the memory 43 during the pull-down cooling operation. That is, the set temperature SP set by the user is, for example, a set temperature during a control cooling operation for cooling stored items such as food. The set temperature SP during the pull-down cooling operation is cooled from a temperature considerably higher than that during the control cooling operation to a temperature range during the control cooling operation, for example, when the power is turned on after the storage 10 is installed. At the set temperature. In the present embodiment, for convenience, each set temperature is set to the same temperature, but each set temperature may be set to a different temperature.

The memory 43 includes a ROM. The ROM stores a map shown in FIG. 3, a program executed by the CPU 41, and the like.
The timer 44 measures an integrated time Σt during a period in which the internal temperature TH is equal to or higher than the predetermined temperature PD. In the present embodiment, the timer 44 measures a sampling interval KS for sampling the internal temperature TH. Then, based on the sampling interval KS, the integration time Σt is measured by the CPU 41. In the present embodiment, the sampling interval KS is, for example, 2 minutes (see FIGS. 5 and 6).

  The counter 45 counts the number of times the CPU 41 samples the internal temperature TH during the period when the internal temperature TH is equal to or higher than the predetermined temperature PD.

  As a basic control of the rotational speed Nm of the inverter motor 21, that is, the rotational speed Nm of the compressor 22, the CPU 41 varies the rotational speed Nm based on the deviation between the internal temperature TH and the set temperature SP. (Rotation speed variable processing) is executed. At that time, the CPU 41 controls the rotational speed Nm to a higher rotational speed as the deviation is larger. For example, as shown in FIG. 3, the CPU 41 controls the rotation speed Nm in seven stages from 0th speed to 6th speed based on the temperature difference BT from the set temperature SP.

  As shown in FIG. 3, the set temperature SP is set to 3 ° C., for example, when the refrigeration chamber 12 is refrigerated as in the present embodiment. In addition, when the cooling storage is a freezer, for example, and the freezing control of the cooling storage is performed, the temperature is set to, for example, −20 ° C.

  The rotation speed Nm is, for example, 0 / s (seconds) for the 0th speed, 30 / s (1800 rpm) for the 1st speed, 42 / s (2520 rpm) for the 2nd speed, and 3rd speed for the 3rd speed. 54 / s (3240 rpm), 4 / speed is 66 / s (3960 rpm), 5th speed is 78 / s (4680 rpm), and 6th speed is 90 / s (5400 rpm).

  Further, the temperature difference BT from each set temperature SP, that is, the temperature boundary set value is, for example, BT1 = 0K (K = absolute temperature range), BT2 = 2K, BT3 = 4K, BT4 = 6K, BT5 = 8K. The Here, SP + SP_U indicates the upper limit value of the set temperature SP, SP-SP_D, and the lower limit value of the set temperature SP, each equal to BT2. That is, SP_U = SP_D = BT2 = 2K. Further, in the present embodiment, the predetermined temperature PD is a temperature obtained by adding BT3 (4K) to the set temperature SP. That is, PD = SP + BT3 (4K). The predetermined temperature PD is not limited to this. For example, PD = SP + BT4 (6K) may be sufficient, and PD> SP + BT5 may be sufficient.

  That is, in the rotation speed variable processing of the inverter motor 21, for example, in the case of refrigeration control, when the internal temperature TH is 11 ° C. or higher, the maximum rotation speed is 6th speed (90 / s). If 5 ° C. ≦ TH <11 ° C., the fifth speed (78 / s) is set. If 7 ° C. ≦ TH <9 ° C., the fourth speed (66 / s) is set. When 5 ° C ≦ TH <7 ° C, the third speed (54 / s) is set. When 3 ° C ≦ TH <5 ° C, the second speed (42 / s) is set, and 1 ° C ≦ TH <3 ° C. In this case, the first speed (30 / s) is set. When the internal temperature TH <1 ° C., the speed is 0 (0 / s), and the compressor 22 is stopped. The predetermined temperature PD is 9 ° C. The relationship between the internal temperature TH and the rotational speed Nm as shown in FIG. 3 is stored in the memory 43 as a map, for example.

  In the present embodiment, the CPU 41 performs a rotation speed fixing process, which will be described later, instead of the rotation speed variable process when a predetermined condition is satisfied during pull-down cooling operation when the power is turned on. In the rotational speed fixing process, the rotational speed Nm of the inverter motor 21 is the maximum rotational speed, in this case, 6 speed (90 / s) until the operation of the compressor 22 is stopped after the internal temperature TH reaches the set temperature SP. ). Here, the rotation speed at the sixth speed (90 / s) is an example of “a high rotation speed near the maximum rotation speed”.

2. Next, with reference to FIG. 4 to FIG. 6, the rotation speed control process of the compressor 22 in this embodiment, that is, the rotation speed control process of the inverter motor 21 will be described. FIG. 5 shows a time chart at the time of pull-down cooling operation when the storage 10 is powered on, and FIG. 6 shows a time chart at the time of control cooling operation for cooling the storage after the pull-down cooling operation. In FIG. 6, before the internal temperature TH decreases to the lower limit (SP-SP_D), the door 15 is opened three times at intervals (see times t10, t13, and t15 in FIG. 6). An example in which the internal temperature TH is lowered to the lower limit (SP-SP_D) is shown. Further, the elapsed time in FIGS. 5 and 6 indicates the time from the start of operation of the compressor 22. The rotational speed control process is executed by the CPU 41 in accordance with a program stored in the memory 43, for example.

  In this process, the CPU 41 first determines whether or not it is during pull-down cooling operation when the power is turned on (step S5). When it is determined that the power is on, that is, when the pull-down cooling operation is being performed (step S5: YES), the rotation speed Nm of the inverter motor 21 is set to the maximum 6-speed (90 / s) (step S10). This timing corresponds to time t0 in FIG.

  On the other hand, if it is determined that the power is not on (step S5: NO), the CPU 41 detects the internal temperature TH via the temperature sensor 35 (step S15). Then, the number of revolutions is determined by referring to the map of the relationship between the detected inside temperature TH and the temperature 43 stored in the memory 43, for example, the inside temperature TH and the number of revolutions Nm shown in FIG. The determined rotational speed is set to the rotational speed Nm (step S20).

  Next, the CPU 41 drives the inverter motor 21 through the inverter drive circuit 36 at the rotation speed Nm set in step S10 or step S20, and also samples the internal temperature TH by the timer 44 KS (2 Minutes) is started (step S25). This timing corresponds to, for example, time t1 in FIG. 5 and time t11 in FIG.

  Next, it is determined whether or not the timer 44 has timed out the sampling interval KS, that is, whether or not the sampling interval KS has elapsed (step S30). When the sampling interval KS has not elapsed (step S30: NO), the drive of the inverter motor 21 at the set rotational speed Nm is continued. On the other hand, when the sampling interval KS has elapsed (step S30: YES), the internal temperature TH is detected via the temperature sensor 35, and the detected internal temperature TH is equal to or higher than a predetermined temperature PD (9 ° C. in the present embodiment). It is judged whether it is (step S35).

  When it is determined that the internal temperature TH is not equal to or higher than the predetermined temperature PD (step S35: NO), the CPU 41, for example, allows the internal temperature TH to temporarily stop the compressor 22, for example, a lower limit value of a set temperature ( SP-SP_D: In this embodiment, it is determined whether or not the temperature has reached 1 ° C. (step S40). When it is determined that the internal temperature TH has not reached the lower limit value (SP-SP_D) of the set temperature (step S40: NO), the process returns to step S20. On the other hand, when it is determined that the internal temperature TH has reached the lower limit value (SP-SP_D) of the set temperature (step S40: YES), the process proceeds to step S75 in order to temporarily stop the internal cooling. Thus, the compressor 22 is temporarily stopped.

  On the other hand, when it is determined in step S35 that the internal temperature TH is equal to or higher than the predetermined temperature PD (step S35: YES), the count value of the counter 45 is incremented (step S45). This timing corresponds to time t2 and time t3 in FIG. Also, this corresponds to time t12 and time t14 in FIG.

  Next, the CPU 41 determines whether or not the count value of the counter 45 is “2” (step S50). The process of step S50 is an example of a determination process for determining whether or not the accumulated time Σt during a period in which the internal temperature TH is equal to or higher than the predetermined temperature PD has reached a predetermined value. In other words, in the present embodiment, the CPU 41 determines that the accumulated time Σt is a predetermined value (this value) when the number of times of sampling of the internal temperature TH that is equal to or higher than the predetermined temperature PD reaches a predetermined number (two in the present embodiment). In the case of the embodiment, it is determined that 4 minutes) has been reached.

  When it is determined that the count value is not “2” (step S50: NO), the process returns to step S5. This timing corresponds to time t2 in FIG. 5 and time t12 in FIG.

  On the other hand, when it is determined that the count value is “2” (step S50: YES), the inverter motor 21 is driven at the maximum rotation speed while the rotation speed Nm is fixed at the sixth rotation speed (90 / s). Is continued (an example of the rotational speed fixing process), and the rotational speed fixed flag is set to “1 (ON)” (step S60). This timing corresponds to time t3 in FIG. 5 and time t14 in FIG. Here, the count value “2” is an example of a predetermined number of times. Note that the predetermined number of times is not limited to two, and may be three, for example.

  Next, as in step S40, the CPU 41 determines whether or not the internal temperature TH has reached, for example, a lower limit value (SP-SP_D) of the set temperature for temporarily stopping the compressor 22. (Step S65). When it is determined that the internal temperature TH has not reached the lower limit value (SP-SP_D) of the set temperature (step S65: NO), the drive of the inverter motor 21 at the maximum rotational speed (90 / s) is continued.

  On the other hand, when it is determined that the internal temperature TH has reached the lower limit value (SP-SP_D) of the set temperature (step S65: YES), the count value and the rotation speed fixing flag are reset to zero (step OFF) (step S65). S70), the rotation speed Nm is set to 0 speed (0 / s), and the compressor 22 is temporarily stopped (step S75). This timing corresponds to time t4 in FIG. 5 and time t16 in FIG.

  Next, the CPU 41 determines whether or not the internal temperature TH has reached the upper limit value (SP + SP_U: 5 ° C. in the present embodiment) of the set temperature (step S80). When it is determined that the internal temperature TH has not reached the upper limit value (SP + SP_U) of the set temperature (step S75: NO), the compressor 22 is kept in a temporarily stopped state. On the other hand, when it is determined that the internal temperature TH has reached the upper limit value (SP + SP_U) of the set temperature (step S80: YES), the compressor 22 is started with the rotation speed Nm as, for example, the third speed (54 / s). (Step S85), the process proceeds to Step S25. This timing corresponds to time t5 in FIG.

3. Effect of this embodiment When the accumulated time Σt during a period in which the internal temperature TH is equal to or higher than the predetermined temperature PD higher than the set temperature SP reaches a predetermined value (4 minutes in the present embodiment), the rotational speed of the inverter motor is The chamber temperature TH is fixed at the maximum rotational speed (sixth speed (90 / s in this embodiment)) at least until the chamber temperature reaches the set temperature. Thereby, when the rotation speed is controlled for the compressor 22 according to the deviation between the internal temperature TH and the set temperature SP, the cooling time to the set temperature SP can be shortened.

  At this time, in the present embodiment, the cumulative time Σt is that the number of times of sampling the internal temperature TH has reached a predetermined number (twice in the present embodiment). That is, the integrated time Σt, which is a determination condition for determining whether or not the rotational speed Nm of the inverter motor 21 is fixed at the maximum rotational speed, is not set as the integrated value of the time itself, but the sampling interval of the internal temperature TH (in this embodiment, By setting the unit to (2 minutes), the determination can be simplified, whereby the rotational speed control of the inverter motor 21 can be simplified.

  Further, when the door 15 is opened and closed during the so-called control cooling operation for cooling the stored item, etc., when the number of samplings does not reach the predetermined number, the CPU 41 executes a rotation speed variable process. Therefore, when the internal temperature TH rises above the predetermined temperature PD by opening and closing the door 15 that is normally performed during the control cooling operation, while performing the rotation speed variable process in a period in which the number of sampling does not reach the predetermined number, When the door 15 is frequently opened and closed, the rotation speed fixing process can be suitably executed before the compressor 22 stops.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention, and further, within the scope not departing from the gist of the invention other than the following. Various modifications can be made.

  (1) In the above embodiment, the CPU 41 sets the internal temperature TH when the sampling count value of the counter 45 reaches “2” (S50: YES), that is, when the accumulated time Σt reaches a predetermined value. Although the example in which the rotational speed fixing process for fixing the rotational speed of the inverter motor to the maximum rotational speed (90 / s) is performed until the compressor 22 is stopped after reaching the temperature SP is shown, the present invention is not limited thereto. Absent. The rotation speed fixing process may be executed at least until the inside temperature TH reaches the set temperature SP. That is, the rotation speed fixing process is completed at the time from the time (t4-1) in FIG. 5 when the internal temperature TH reaches the set temperature SP to the time before time t4, and then the rotation speed is stopped until the compressor 22 is stopped. Variable processing may be performed. Even in this case, when the integrated time Σt reaches a predetermined value during the pull-down cooling operation or the control cooling operation, the time until the internal temperature TH reaches the set temperature SP can be shortened.

  (2) In the above embodiment, the accumulated time Σt shows an example in which the number of samplings for sampling the internal temperature TH has reached a predetermined number (two in this embodiment), but is not limited thereto. . The period itself in which the internal temperature TH is equal to or higher than the predetermined temperature PD may be measured, and the integrated value of the measured period may be set as the integrated time Σt.

  (3) In the above embodiment, the example in which the predetermined temperature PD is set to the fixed temperature “set temperature SP + BT4” is shown, but the present invention is not limited thereto. For example, the predetermined temperature PD may be different between the pull-down cooling operation (see FIG. 5) and the control cooling operation (see FIG. 6).

(4) In the above embodiment, the rotation speed of the inverter motor is controlled in seven stages from the lowest speed of 0 speed to the highest speed of 6 speeds, and the speed of the highest speed of 6 speeds (90 / s) is set to “highest speed”. Although an example of “a high rotation speed in the vicinity of the number” has been shown, the present invention is not limited to this. That is, the “high rotation speed near the maximum rotation speed” is not limited to the highest rotation speed. For example, the fifth speed (78 / s) may be set as “a high rotational speed near the maximum rotational speed”. Or it is good also considering the rotation speed in the range from 85% (76.5 / s) of the maximum speed to the maximum speed (90 / s) as "the high rotation speed near the maximum rotation speed".
Further, the stage (step) control of the rotational speed Nm is not limited to the seven-stage control, and may be, for example, a 16-stage or 32-stage control. At that time, the number of rotations corresponding to the speed of the stage up to several steps below the highest speed may be set to “high rotation speed near the highest speed” according to the number of stages, or from 85% of the highest speed to the highest speed. The number of rotations in the range may be set as “a high number of rotations near the maximum number of rotations”.

  (5) In the above embodiment, regarding the sampling interval KS for sampling the internal temperature TH, the sampling interval KS for executing the rotation speed fixing process in step S60 and the sampling interval KS at the time of normal rotation speed control are set. For example, although the example which makes it the same in 2 minutes was shown, it is not restricted to this. For example, the normal rotation speed control process (rotation speed variable process) and the process related to the execution of the rotation speed fixing process (for example, the processes in steps S25 to S75 in FIG. 4 excluding step S40) are executed in parallel. The sampling interval KS in the normal rotation speed control process may be shorter than the sampling interval KS in the process for executing the rotation speed fixing process. Further, when executing the parallel processing, if the condition for executing the rotation speed fixing process is satisfied (for example, step S50: YES in FIG. 4), the rotation speed fixing process is prioritized, and the compressor 22 When stopped, the normal rotational speed control process may be restarted.

  (6) In the said embodiment, although the example of the vertical refrigerator for business was shown as a cooling storage, it is not restricted to this. The cooling storage can be, for example, a commercial vertical freezer, or a horizontal cooling storage having a refrigerator compartment and a freezer compartment. Moreover, it is not limited to a commercial refrigerator or freezer, and may be a general household refrigerator or freezer.

  DESCRIPTION OF SYMBOLS 10 ... Thermal insulation storage, 12 ... Cold room, 21 ... Inverter motor, 22 ... Compressor, 26 ... Capillary tube (throttle device), 27 ... Cooler, 35 ... Temperature sensor, 36 ... Inverter drive circuit, 41 ... CPU, 44 ... Timer, 45 ... Counter

Claims (6)

A compressor driven by an inverter motor;
A condenser that dissipates heat from the refrigerant compressed by the compressor;
A cooler in which refrigerant from the condenser is supplied through a throttling device;
A storage room having a storage room, wherein the storage room is cooled by the cold air generated by the cooler;
A temperature sensor for detecting the internal temperature of the storage chamber;
A timer that measures an accumulated time of a period in which the internal temperature is equal to or higher than a predetermined temperature that is higher than a set temperature that is a target temperature for cooling;
A rotation speed control unit that executes a rotation speed variable process for changing the rotation speed of the inverter motor according to a deviation between the internal temperature and the set temperature;
With
The rotation speed control unit
A determination process for determining whether or not the accumulated time has reached a predetermined value;
When it is determined in the determination process that the accumulated time has reached the predetermined value, the rotation speed of the inverter motor is fixed at a high rotation speed near the maximum rotation speed until at least the internal temperature reaches the set temperature. Rotation number fixing processing to
Perform the cooling storage. In the cooling storage of Claim 1,
With a counter,
The rotation speed control unit samples the internal temperature from the temperature sensor at predetermined sampling intervals,
The timer measures the sampling interval,
The counter counts the number of times the rotation speed control unit samples the internal temperature in a period in which the internal temperature is equal to or higher than the predetermined temperature,
The said rotation speed control part is a cooling storehouse which judges that the said integration time has reached the said predetermined value, when the said frequency | count of sampling reaches the predetermined number in the said determination process. In the cooling storage of Claim 2,
The rotation speed control unit
A cooling storage that performs the rotation speed variable processing when the sampling count does not reach the predetermined count. A compressor driven by an inverter motor; a condenser for radiating heat from the refrigerant compressed by the compressor; a cooler to which the refrigerant from the condenser is supplied through a throttling device; and a storage chamber, the cooler A method for controlling the rotational speed of the compressor of the cooling storage comprising a storage in which the storage chamber is cooled by the cold air generated by
A detection step of detecting the internal temperature of the storage chamber;
A rotational speed variable step of varying the rotational speed of the inverter motor according to a deviation between the internal temperature and a set temperature that is a cooling target temperature;
A measuring step of measuring an accumulated time of a period in which the internal temperature is equal to or higher than a predetermined temperature that is higher than the set temperature;
A determination step of determining whether or not the accumulated time has reached a predetermined value;
If it is determined in the determination step that the accumulated time has reached the predetermined value, the rotation speed of the inverter motor is set to a high rotation speed near the maximum rotation speed until at least the internal temperature reaches the set temperature. A rotational speed fixing process for fixing;
A method for controlling the rotational speed of the compressor. In the compressor rotation speed control method according to claim 4,
In the detection step, the internal temperature is sampled at predetermined sampling intervals,
In the measuring step, the number of times of sampling the internal temperature in a period in which the internal temperature is equal to or higher than the predetermined temperature is counted,
In the determination step, when the number of sampling times reaches a predetermined number, it is determined that the integration time has reached the predetermined value. In the compressor rotation speed control method according to claim 5,
A method for controlling the rotational speed of a compressor, wherein the rotational speed varying step is performed when the number of samplings does not reach the predetermined number.

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