JP4445835B2 - Cooling storage - Google Patents

Description

  The present invention relates to a cooling storage, and more particularly, to a cooling storage with an improved control of cooling operation.

In recent years, for example, commercial refrigerators are equipped with inverter compressors capable of speed control and control the cooling temperature in the cabinet by increasing and decreasing the speed (for example, see Patent Document 1).
In general, when temperature adjustment is performed, PID control using a temperature deviation (control system including three operations of proportionality, integration, and differentiation) is applied. Specifically, for the refrigerator, the increase / decrease in the number of revolutions of the inverter compressor, which is the control value, is determined based on the deviation between the set temperature, which is a certain target, and the detected temperature, which is the actual value. Will do.
JP 2002-13858 A

However, in the method as described above, when the target fluctuates, for example, when control is performed such that the internal temperature is lowered from 5.0 ° C. to 1.0 ° C. in 30 minutes, the target value (temperature) is determined depending on the elapsed time. There is a problem that the control system becomes complicated because it is necessary to reset the details.
The present invention has been completed on the basis of the above-described circumstances, and an object thereof is to provide a control method suitable for use mainly when the target interior temperature fluctuates.

Invention 請 Motomeko 1, in cooling storage is inside the refrigerator is cooled by a cooling apparatus having a speed control capable inverter compressor, cooling showing a descent mode of the internal temperature in a certain control time to be targeted Storage means for storing the characteristics as data, a temperature sensor for detecting the internal temperature, and operation control means for controlling the speed of the inverter compressor are provided , and this operation control means is provided for a predetermined time from the start of control. A scheduled elapsed time calculation unit that takes out the internal temperature detected by the temperature sensor each time it elapses, and calculates an estimated elapsed time to reach the detected temperature on the cooling characteristics stored in the storage unit; The actual elapsed time is compared with the scheduled elapsed time output from the scheduled elapsed time calculation unit, and the cooling status is delayed, based on the comparison result, whether the advance or neutral Based on the determination result of the determination unit and the determination unit, a speed increase command is issued in the delay state, a deceleration command in the advance state, and a constant speed command in the neutral state. , And a command unit that outputs to the inverter compressor .

According to a second aspect of the invention, there is provided a connector described in claim 1, before SL to the command unit, than the timing of outputting the speed-increasing command to the inverter compressor with the delay determination, the process proceeds with the determination the inverter compressor It is characterized in that it is provided with a sensitivity correction function that accelerates the timing of outputting a deceleration command.

According to a third aspect of the present invention, in the first or second aspect of the present invention, an internal temperature gradient calculation unit that calculates an internal temperature gradient every predetermined sampling time based on a signal from the temperature sensor is provided. The command unit is characterized in that an output stop function is provided to stop outputting the acceleration or deceleration command when the internal temperature gradient exceeds a predetermined value.
A fourth aspect of the present invention, there is provided a connector described in any one of claims 1 to 3, the inside temperature gradient calculator for calculating a-compartment temperature gradient for each predetermined sampling time based on the signal of the temperature sensor The command unit is characterized in that it has a control interval changing function for changing an interval for outputting the acceleration or deceleration command based on an internal temperature gradient.

<Invention of Claim 1 >
Every time after the start of control, the actual cooling progress status with respect to the target cooling characteristics is judged. If it is in the delayed state, the speed increase command is sent to the inverter compressor, and if it is in the advanced state, the speed reduction command is sent. If the vehicle is in the neutral state, constant speed commands are output, and the internal temperature is controlled so as to follow the target cooling characteristics.
In particular, it is possible to stably perform the control in which the target value fluctuates with the passage of time, such as lowering the internal temperature by a predetermined temperature during a predetermined time.
<Invention of Claim 2 >
For example, in a refrigerator, the latter is easier to improve in the overcooled state and the undercooled state.
Therefore, in the corrected control, when the delay is determined, the speed increase command is issued to the inverter compressor, whereas when the advance is determined, the sensitivity of issuing the deceleration command is increased, that is, the deceleration is performed relatively early. By giving a command, rational control is achieved.

<Invention of Claim 3 >
If the temperature gradient inside the storage chamber is increasing rapidly due to insufficient cooling, and if a speed increase command is issued only in relation to time, there is a risk that the cooling will proceed extremely and the processing will fail. Because there is, this command is not issued. On the other hand, if the deceleration command is issued while the temperature gradient is already increased while the vehicle is decelerating from the overcooled state, the internal temperature may increase unnecessarily, so the command is not issued. Excessive cooling in the chamber and temperature rise are prevented.
<Invention of Claim 4 >
If the command update control is frequently performed when the internal temperature gradient is small, the cooling capacity changes unnecessarily, and conversely, if the internal temperature gradient is large, if the control is not performed for a long time, the control range is deviated. Or hunting (runout) may increase.
Therefore, the control interval is changed so that the control interval is short when the internal temperature gradient is large, and the control interval is long when the internal temperature gradient is small. Thereby, the said malfunction is eliminated.

<Embodiment>
Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
First, the overall structure of the refrigerator will be described with reference to FIG. The refrigerator main body 10 is composed of a vertically insulated heat insulating box with a front opening, and the inside is a storage chamber 11. The front opening is formed with two upper and lower entrances 12, and the heat insulating door 13 can be swingably opened and closed. It is attached to.
A machine room 15 is provided on the upper surface of the refrigerator body 10, and a refrigeration device 16 is installed therein. The refrigeration apparatus 16 includes an inverter compressor 17, an air-cooled condenser 18, and the like, and is mounted on a heat-insulating base 19 as a unit. The base 19 is an opening on the ceiling surface of the storage chamber 11. 11A is closed and attached.

An air duct 21 that also serves as a drain pan is stretched on the ceiling portion of the storage chamber 11, and a cooler chamber 22 is formed above the air duct 21. A suction port 23 is formed in the area on the front side of the air duct 21, and a blow-out port 24 is formed on the back side. The cooler chamber 22 is provided with a cooler 25 (evaporator) and an internal fan 26 facing the suction port 23, and the cooler 25 is circulated and connected to the refrigerating device 16 through a refrigerant pipe, and the refrigerating cycle. Is configured.
When the internal fan 26 is driven while operating the refrigeration apparatus 16 (inverter compressor 17), the indoor air in the storage chamber 11 is sucked into the cooler chamber 22 from the suction port 23 by the internal fan 26, and the air The cold air is generated by heat exchange while flowing through the cooler 25, the cold air is blown out from the outlet 24 along the inner surface of the storage chamber 11, and the cold air is circulated and supplied into the storage chamber 11 for cooling. It has come to be.

Subsequently, control of the internal temperature will be described. In this embodiment, the control at the time of the control operation which maintains the inside of a store | warehouse | chamber near the preset temperature is illustrated. For example, in a refrigerator, if the set temperature is 3 ° C, the interior temperature is 2K higher than that by 5 ° C ( When the temperature reaches the upper limit temperature), cooling is started, and when the temperature drops to 1 ° C. (lower limit temperature), which is 2K lower than the set temperature, the cooling is stopped and the interior is maintained near the set temperature (3 ° C.). It is like that.
Taking the above behavior as an example, a case where the temperature control target is set to pass from 5 ° C. (upper limit temperature) to 1 ° C. (lower limit temperature) over 30 minutes will be described as an example.

  As shown in FIG. 2, the control mechanism includes a control unit 30 that includes a microcomputer or the like and executes a predetermined program. The control unit 30 includes a data storage unit 31, a timer Tx (operation time). Timer), scheduled elapsed time calculation unit 33, determination unit 34, command unit 35, internal temperature gradient calculation unit 38, and the like. An internal temperature sensor 27 for detecting the internal temperature is connected to the input side of the control unit 30, and the inverter compressor 17 is connected to the output side via an inverter circuit 36. The inverter compressor 17 can change the speed in, for example, seven stages.

First, basic control of this embodiment will be described. In this embodiment, as shown in FIG. 3, the target of temperature control is set so as to pass from 5 ° C. (upper limit temperature) to 1 ° C. (lower limit temperature) over 30 minutes. The cooling characteristic, i.e., the temperature curve A (straight line) is stored in the data storage unit 31.
As a basic operation, when the internal temperature reaches 5 ° C., the operation time timer Tx is reset and the time elapses, that is, the control is started. Then, the progress of cooling is judged at appropriate time intervals (standard is 1 minute), and if the cooling is delayed, the inverter compressor 17 is accelerated, and if the cooling proceeds, the inverter compressor 17 is decelerated. Is done.

For example, when the internal temperature detected by the internal temperature sensor 27 is tx (° C.) after an arbitrary time Tx (minutes) has elapsed since the start of control, the target temperature curve stored in the data storage unit 31 described above. In A, the estimated elapsed time Tr (minutes) that should reach the temperature tx (° C.) is calculated by the estimated elapsed time calculation unit 33 according to the following equation (1) (see also the parameters in FIG. 11).
Tr = 30 × (5-tx) ÷ (5-1) (1)
Next, in the determination unit 34, a time deviation Td (minute) between the actual elapsed time Tx (minute) and the calculated estimated elapsed time Tr (minute) is calculated by the following calculation formula (2). .
Td = Tx−Tr (2)
Here, if “Td <0”, it indicates that the cooling has progressed more than planned, and conversely if “Td> 0”, this indicates that it is behind schedule.
For example, if the elapsed time Tx = 5 (minutes) from the start of control and the detected temperature tx = 3 (° C.), the expected elapsed time Tr = 15 (minutes) and the time deviation Td = −10 (minutes) Become.

In the case of the above example, it shows that the progress of cooling is progressing 10 minutes earlier than planned, and it can be understood that the cooling capacity may be lowered to correct this. As described above, in this embodiment, the “deviation” is expressed not by temperature but by time.
That is, the time deviation Td is calculated, and as shown in the temperature characteristic B1 of FIG. 4, when there is a delay deviation, a cooling capacity increase command is issued, that is, the inverter compressor 17 is accelerated through the inverter circuit 36. As a result, the gradient of the subsequent temperature drop becomes steep. On the other hand, as shown in the temperature characteristic B2 of the figure, when there is a lead deviation, a cooling capacity reduction command is issued, and the inverter compressor 17 is similarly decelerated through the inverter circuit 36, and the gradient of the temperature drop becomes gentle. .
By performing the operation as described above at appropriate time intervals (for example, every minute), it is possible to control the internal temperature with the passage of time as a parameter.

Although the basic operation is as described above, in view of the fact that the control target is a refrigerator, the following control correction is added.
In the refrigerator, the latter can be more actively intervened in an overcooled state (internal temperature too low) and an undercooled state (internal temperature too high). In situations where cooling is insufficient, increasing the cooling capacity is an appropriate measure for improving the situation.
On the other hand, as an active intervention in the case of excessive cooling, introduction of heat into the cabinet using a defrost heater or the like can be considered, but generally such control is not performed. At this time, if the compressor 17 is stopped, the overcooled situation can be improved, but since the compressor 17 cannot be started for protection for several minutes after the stop, how the internal temperature changes during that period. This method cannot be used due to many problems such as unpredictability.
Therefore, in practical use, the cooling capacity is lowered while the compressor 17 is operated, and the passive response such as waiting for the scheduled time to arrive while increasing the internal temperature or maintaining the internal temperature due to the intrusion heat from the outside. Inevitably, it is difficult to control until the planned cooling condition is restored.

Therefore, in the corrected control, the sensitivity of issuing the cooling capacity decrease command when the advance determination is made is increased as opposed to issuing the cooling capacity increase instruction when the delay is determined. For example, as shown in the temperature characteristic C1 of FIG. 5, when the capacity is being increased from the insufficient cooling state, the cooling capacity decrease command is issued as early as possible (point p1) after the transition from delay to advance. On the contrary, as shown in the temperature characteristic C2 in the figure, when the capacity is decreasing from the excessive cooling state, even if the transition is made from the advance to the delay, if the cooling capacity increase command is issued in a delayed manner (point p2), Reasonable control.
Specific numerical values relating to this correction control are shown in the table of capability change determination shown in FIG.

  Next, the temperature gradient (K / min) for the past 1 minute is added as an auxiliary condition for the determination of delay / advance. The internal temperature gradient is calculated by the internal temperature gradient calculating unit 38 stored in the control unit 30. Specifically, the internal temperature gradient is obtained every 5 seconds (using the measurement interval timer Ti) by the internal temperature sensor 27. Is obtained by comparing it with the data one minute ago.

In FIG. 6, the capacity is increasing from the undercooled state as shown by the temperature characteristic D1, and the gradient of the internal temperature suddenly drops as shown at the point p3. If an increase command is issued, the cooling does not proceed as shown in the characteristic d1 and the processing may fail, so the command is not issued. If it is a gentle temperature gradient of about the point p4 of the temperature characteristic D1, a cooling capacity increase command is issued.
On the other hand, as shown by the temperature characteristic D2 in the figure, when the capacity is decreasing from the excessive cooling state and the temperature gradient has already increased as shown at the point p5, if the cooling capacity is further decreased, the characteristic d2 is obtained. As shown, since the internal temperature rises unnecessarily, no cooling capacity decrease signal is issued. A cooling capacity reduction command is issued if the degree of gradual drop is as indicated by point p6 of the temperature characteristic D2.
Specific numerical values are shown in the table of capability change restrictions shown in FIG.

The control interval is typically one minute, but if the update is performed frequently when the internal temperature gradient is small, the ability changes unnecessarily. On the contrary, if the temperature gradient inside the chamber is large and the control is not performed for a long time, the controllable range may be deviated or hunting (shake) may increase.
As countermeasures to reduce this, as shown in the graph of FIG. 7 and the table of the shortest judgment time of FIG. 10, on the temperature characteristic E, when the internal temperature gradient is large, the control interval is short and the internal The control interval is changed so that the control interval becomes longer when the temperature gradient is small. In particular, the sensitivity is set high when the internal temperature with limited control capability is a downward gradient.

The operation of the present embodiment in which correction control is added to the basic control as described above will be described as follows based on the flowcharts of FIGS. There is an operation condition Cd as a parameter other than that described above, which indicates whether the actual cooling state is an advanced state, a delayed state, or a neutral state with respect to the target, and Cd = 1 (positive) Number), Cd = −1 (negative number) and Cd = 0.
In this flowchart, the timing of various timers, the scheduled elapsed time Tr, and the progress time Td are indicated by the unit “second”.

When the control is started, the operation condition “Cd = 0” is set in step S10, the operation time timer Tx is reset, and the calculation formula (1) is set.
After that, step S11 and subsequent steps are repeatedly executed. First, every 5 seconds, an internal temperature gradient is acquired based on the internal temperature tx obtained from the internal temperature sensor 27, and the estimated elapsed time Tr is calculated (steps S11 and S12).
After that, progress calculation and update time calculation based on the temperature gradient are performed in step S16. Before that, if the detected internal temperature is lower than the end temperature Te (1 ° C.) (step S13 is “ Yes ”), the control ends as the cooling ends, and if the internal temperature is higher than the start temperature Ts (5 ° C.) (“ Yes ”in step S14), the control ends similarly as being in a high temperature state. .

  If the temperature gradient exceeds “2” (step S15 is “Yes”), the “start condition setting” subroutine shown in FIG. 15 is executed. The fact that the temperature gradient exceeds “2” indicates that the internal temperature has suddenly increased during the control. Therefore, the estimated elapsed time Tr is calculated again from the detected internal temperature (step S70), If the scheduled elapsed time Tr is negative (step S71 is “No”), the internal temperature is out of the control temperature range (5 ° C. to 1 ° C.), so the operation time timer Tx is reset (step S72). On the other hand, if the scheduled elapsed time Tr is equal to or greater than 0 (“Yes” in step S71), the internal temperature remains within the control temperature range, and thus the operation time timer Tx is reset when Tr seconds have elapsed.

  In step S16, as described above, the calculation of the progress time Td and the calculation of the update time based on the temperature gradient are executed. When the update timing comes (step S17 is “Yes”), the speed control of the inverter compressor 17 is performed. The speed control is classified over steps S18 to S25, and as shown in the table of capability change determination in FIG. 8, "speed increasing process", "speed control" according to the condition of the operation condition Cd and the progress time Td. The “deceleration process” and “constant speed process” subroutines are executed.

As shown in FIG. 12, in the “acceleration process”, if the temperature gradient is “−2” or less (“Yes” in step S30), the process ends without issuing an acceleration command. If the temperature gradient exceeds “−2” (step S30 is “No”), a speed increase command is issued in step S31. If the speed increase of the inverter compressor 17 is successful (step S32 is “Yes”), the operation condition Cd at the time of entering the control is confirmed, and if it is in a delayed state (step S33 is “Yes”), the step If “Cd = 0” is set in S34, and if the vehicle is in a neutral or advanced state (Step S33 is “No”), “Cd = 1” is set in Step S35, and then the speed is set in Step S36. The update timer Tf is reset and the process ends. If the inverter compressor 17 is at the maximum speed or the like and the speed cannot be increased (step S32 is “No”), the speed update timer Tf is reset as it is and ends.
When the acceleration process is completed, the process returns to step S11 of the main routine, and the inverter compressor 17 is increased until the time measured by the speed update timer Tf exceeds the previously set update time ("No" at step S17). Driven at speed (maintained at maximum).

As shown in FIG. 13, in the “deceleration process”, when the temperature gradient is “0” or more (“Yes” in step S40), “Cd = 1” is set without issuing a deceleration command (step S40). S41), the process ends. If the temperature gradient is less than “0” (step S40 is “No”), the operation condition at the time of entering the control is confirmed in step S42.
If the operation condition is in the advanced state (“Yes” at step S42), a deceleration command is issued at step S43. Subsequently, in step S44, the temperature gradient is confirmed. If the temperature gradient is “−0.1” or more (step S44 is “Yes”), “Cd = 0” is set in step S45, while the temperature gradient is If it is less than “−0.1” (“No” in step S44), “Cd = −1” is set in step S46, and thereafter, in step S47, the speed update timer Tf is reset and the process ends. To do.

If the operation condition Cd is neutral or delayed (“No” at step S42), a deceleration command is issued at step S48. If the inverter compressor 17 is successfully decelerated (“Yes” in step S49), “Cd = −1” is set in step S50, the speed update timer Tf is reset in step S47, and the process ends. When the inverter compressor 17 is at the minimum speed or the like and cannot be decelerated (“No” in step S49), the speed update timer Tf is reset as it is and the process ends.
When the deceleration process is completed, the process returns to step S11. Similarly, the inverter compressor 17 is decelerated (minimum) until the time measured by the speed update timer Tf exceeds the previously set update time (step S17 is “No”). In the case of (maintained) speed.

  In the case of “constant speed processing”, as shown in FIG. 14, the processing is completed on the condition that the time of the speed update timer Tf does not exceed 300 seconds (“No” in step S60), that is, the inverter The compressor 17 continues to be driven at the previous speed without being increased or decreased. Returning to the main routine, if the time measured in the speed update timer Tf exceeds the previously set update time (“Yes” in step S17), the process continues thereafter, and after the determination in steps S18 to S25, the inverter The speed control of the compressor 17 is executed.

As a result of the acceleration process and the deceleration process, a value of “Cd ≠ 0” may be taken regardless of the state of riding on the descending slope (target temperature curve). “Cd = 0” when riding on the specified descent slope, and when taking other values, it is considered that the capacity is inherently insufficient or excessively corrected. Is different. The optimum operating speed of the compressor for placing it on the specified descending slope is dynamically changing due to factors such as the internal temperature.
For example, if a delay is detected at “Cd = 0” at a certain point in time, “Cd = 1” is obtained when the speed is increased. At this time, in order to suppress an excessive descent, the vehicle is decelerated if it becomes advancing even a little. If the internal temperature decreases, the difference from the outside air temperature becomes large. Therefore, what was previously excessive in capacity may become an appropriate capacity by increasing the speed at this point. In other words, in that case, the neutral state is maintained indefinitely with “Cd = 1”.
If such a situation occurs, it is more appropriate that the operation condition of FIG. 8 is determined not in the advanced state but in the neutral state. In order to cope with such a situation, if the speed does not change for more than 300 seconds (“Yes” in step S60), it is determined that the temperature change is changing as planned, and in step S61. The operation condition is set to “Cd = 0” and the determination condition is returned to neutral. At this time, the speed update timer Tf is also reset in step S62.

  As described above, according to the present embodiment, as a basic control mode, the speed control of the inverter compressor 17, that is, the control of the cooling capacity is performed by looking at the time progress of the cooling. During control operation of the refrigerator, this can be stably performed for control in which the target value varies with time, such as lowering the internal temperature by a predetermined temperature during a predetermined time. In particular, the control system can be simplified as compared with PID control using temperature deviation that requires the target value to change with time.

In addition, by taking into account the following correction control, it is possible to realize a control that is more suitable for the actual condition of the refrigerator.
In the refrigerator, in view of the fact that the latter is easier to improve in the overcooled state and the undercooled state, in response to issuing a speed increase command to the inverter compressor 17 when a delay is determined, By increasing the sensitivity of issuing a deceleration command when advancing is determined, that is, issuing a speed-up command relatively early, the control is rational.

Furthermore, by using the internal temperature gradient as an auxiliary condition, the control is more excellent in consistency.
For example, when the speed is increasing due to insufficient cooling rejection, and the temperature gradient inside the storage is rapidly decreasing, if the speed increasing command is issued only in relation to the time, the cooling will proceed extremely and the processing will fail. Do not issue this directive because there is a risk. On the other hand, if the deceleration command is issued while the temperature gradient is already increased while the vehicle is decelerating from the overcooled state, the internal temperature may increase unnecessarily, so the command is not issued. As a result, excessive cooling and temperature rise in the cabinet are prevented.

  In addition, if the command update control is frequently performed when the internal temperature gradient is small, the cooling capacity changes unnecessarily, and conversely, if the internal temperature gradient is large, if the long time control is not performed, the controllable range Control, the control interval is short when the internal temperature gradient is large, and the control interval is long when the internal temperature gradient is small. By changing the interval, the above problem is solved.

When updating the speed control, the operation condition (advanced state, delayed state, or neutral state) at the time of entering the update is used as the determination condition, so it is possible to perform highly accurate control without bringing in a predicted response or the like. .
If the internal temperature gradient is monitored, the arrival of the internal temperature in the relatively short-term future can be predicted. For example, when the inside temperature is falling stably and can be used for control, it is relatively easy to obtain the time to reach an arbitrary temperature. Therefore, if control is performed to increase or decrease the cooling when the target temperature is not reached using these, it can be said that the control is based on the predicted response. However, this control is difficult to adjust when the internal temperature fluctuates significantly.
In this respect, in this embodiment, since an operation condition that does not require any adjustment is used as a determination condition, a control with good response and stability can be realized.

<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) The temperature control target exemplified in the above embodiment is merely an example, and the target control time and the temperature drop can be arbitrarily selected.
(2) Moreover, this invention is applicable not only at the time of the control operation of a refrigerator, but also to the control at the time of the pull-down operation which cools the inside from a high temperature state to the preset temperature vicinity.

(3) Various parameters and numerical values exemplified in the above embodiment are merely examples, and can be arbitrarily set.
(4) In the above-described embodiment, various correction controls are exemplified. However, depending on conditions such as the type of the refrigerator, the correction control may not be necessary, and the correction control is appropriately omitted. Included in the technical scope.

( 5 ) The present invention is widely applied to all cooling storages that require temperature control to change the temperature inside the refrigerator as time passes, such as a freezer, a refrigerator, a constant temperature and high humidity storage, etc. can do.

The fragmentary longitudinal cross-section which shows the internal structure of the refrigerator of one Embodiment of this invention Block diagram of internal temperature control mechanism Graph showing target temperature curve Graph explaining basic control operation Graph explaining the difference in sensitivity between acceleration control and deceleration control Graph explaining the case of limiting acceleration control and deceleration control Graph explaining the difference in control interval Chart showing ability change determination Table showing the ability change limit Table showing the shortest judgment time Flow chart of temperature control main routine Flow chart of subroutine related to acceleration processing Flow chart of subroutine related to deceleration processing Subroutine flowchart for constant speed processing Subroutine flowchart for starting condition setting

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Refrigerator main body 11 ... Storage room 16 ... Refrigeration apparatus (cooling device) 17 ... Inverter compressor (compressor) 27 ... Inside temperature sensor (temperature sensor) 30 ... Control part (operation control means) 31 ... Data storage part ( Storage means) 33 ... scheduled elapsed time calculation unit 34 ... determination unit 35 ... command unit 36 ... inverter circuit 38 ... internal temperature gradient calculation unit Tx ... operating time timer A ... (target) temperature curve

Claims (4)

In the cooling storage where the inside is cooled by a cooling device equipped with an inverter compressor capable of speed control ,
Storage means in which the cooling characteristics indicating the manner in which the internal temperature falls within a target control time that is targeted are stored as data, a temperature sensor that detects the internal temperature, and an operation that controls the speed of the inverter compressor Control means ,
This operation control means
Each time a predetermined time elapses from the start of control, the internal temperature detected by the temperature sensor is taken out, and the estimated elapsed time to reach the detected temperature on the cooling characteristic stored in the storage means is calculated. A scheduled elapsed time calculator,
Judgment that compares the actual elapsed time and the scheduled elapsed time output from the scheduled elapsed time calculation unit, and determines whether the cooling state is delayed, advanced or neutral based on the comparison result And
Based on the determination result of the determination unit, a command for outputting to the inverter compressor an acceleration command in the case of a delay, a deceleration command in the case of an advance, and a constant speed command in the case of a neutral state. The cooling storage characterized by being comprised from the part . The command unit has a sensitivity correction function that makes the timing for outputting a deceleration command to the inverter compressor in accordance with the advance determination faster than the timing for outputting the acceleration command to the inverter compressor in accordance with the delay determination. The cooling storage according to claim 1 , wherein the cooling storage is. An internal temperature gradient calculation unit that calculates an internal temperature gradient at predetermined sampling times based on the signal from the temperature sensor is provided, and the command unit increases the increase if the internal temperature gradient exceeds a predetermined value. The cooling storage according to claim 1 or 2, further comprising an output stop function for stopping output of a speed or deceleration command. An internal temperature gradient calculation unit that calculates an internal temperature gradient for each predetermined sampling time based on a signal of the temperature sensor is provided, and the command unit is configured to increase or decrease the speed based on the internal temperature gradient. cold storage according to any one of claims 1 to 3, characterized in that the control interval changing function of changing the interval for outputting a command is provided.

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