JP2009228922A - Refrigerating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem in an operation of a compressor by a conventional invertor device that following capability can not be sufficiently secured though its purpose is promotion of increase of output frequency in shortage of refrigerating capacity and decrease of the output frequency in excess of refrigerating capacity. <P>SOLUTION: This refrigerating device comprising a refrigerant circuit constituted by communicating a compressor, a condenser, a throttle means and an evaporator by refrigerant pipes, and the invertor device of variable output frequency for driving the compressor, further includes a compressor operation time detecting means, a compressor target stop time setting means, a target low pressure-side pressure setting means, a low pressure-side pressure detecting means, and an invertor control means, thus the frequency of the invertor device is effectively changed, and the refrigerating device of high following capability of an indoor temperature and an operating state can be provided. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a refrigeration apparatus, and more particularly to a refrigeration apparatus for inverter-controlling a compressor.

In the conventional refrigeration apparatus, an inverter device is used for the operation of the compressor, and the change in the low pressure side pressure value due to the load fluctuation of the evaporator is followed to realize the proper operation of the compressor.
However, the operation of a compressor by a conventional inverter device can generally be considered as a capacity shortage tendency when the low pressure side pressure value is high, and an overcapacity tendency when the low pressure side pressure value is low. Although the aim is to promote a decrease in the output frequency when there is a tendency to increase or excess capacity, the followability has not been sufficiently secured. In addition, even when a large amount of refrigeration capacity is required, such as at the start of operation, the upper limit of the capacity is suppressed by the target pressure, and it may take a long time for the internal temperature to reach a predetermined value.
In order to solve these problems, a technique for controlling the output frequency of the inverter device based on the frequency of starting and stopping of the compressor is known from Patent Document 1 below.

JP 2002-115923 A

  However, in this method, the frequency of start / stop is expressed as the number of operations / stops. That is, since the start / stop frequency is set as a cycle of the operation time and the stop time of the compressor, it is necessary to measure the stop time not directly related to the control during operation. Further, even when the operation time is long and a good operation state is maintained, if there is a short stop time, it becomes a target of the start / stop frequency, and the operation of the refrigeration apparatus may be controlled.

The present invention has been made in view of the conventional problems described above, and pays attention to the operation time of the compressor, and is used for driving the compressor according to the length of the operation time or the average frequency of the inverter device during the operation time. An object of the present invention is to provide a refrigeration apparatus having high followability between the room temperature and the operating state by effectively changing the frequency of the inverter device.

  In order to achieve the above object, a refrigeration apparatus according to the present invention comprises a refrigerant circuit in which a compressor, a condenser, a throttle means and an evaporator are connected by refrigerant piping, and an inverter device having a variable output frequency for driving the compressor. In the refrigeration apparatus provided, from the detected values of the compressor operating time detecting means for detecting the operating time of the compressor, the compressor target operating time setting means for setting the target operating time of the compressor, and the compressor operating time detecting means Based on the determined compressor operating time and the set value of the compressor target operating time setting means, the target low pressure side pressure setting means for setting the target value of the low pressure side pressure that is the suction side of the compressor, and the low pressure side pressure A low pressure side pressure detecting means for detecting, and an inverter control means for controlling the output frequency of the inverter device based on the detected value of the low pressure side pressure detecting means and the set value of the target low pressure side pressure setting means. It is intended.

  According to the refrigeration apparatus according to the present invention, the target value of the low-pressure side pressure is set based on the compressor operation time obtained from the detected compressor operation time and the set target operation time of the compressor. Since the output frequency of the inverter device is controlled based on the target value and the low pressure side pressure detection value, the inverter device can be operated efficiently. Therefore, in spite of the fact that the compressor has an inverter device as in the conventional refrigerator, in the actual use, the inverter device is under the maximum frequency for a short time during the operation time of the compressor. Since there is no such thing as driving, it is possible to reduce the power consumption of the refrigerator.

Embodiment 1 FIG.
1 is a block diagram showing a configuration of a refrigeration apparatus in Embodiment 1 of the present invention.
In the figure, the refrigerating and air-conditioning apparatus according to Embodiment 1 includes a refrigerant circuit in which a compressor 1, a condenser 2, a throttle means 3, and an evaporator 4 are annularly connected by a refrigerant pipe 13. The compressor 1 is driven by a motor 15 that rotates with an inverter device 14 so that the operation frequency is variable.
First, the inverter control means 9 is communicatively connected to the compressor operating time detecting means 5 and further connected to the target low pressure side pressure setting means 7 together with the compressor target operating time setting means 6. The target low pressure side pressure setting means 7 is connected to the inverter control means 9 together with the low pressure side pressure detection means 8, and the compressor 1 is operated by the inverter device 14 in response to a signal from the inverter control means 9.

Next, the control flow will be described with reference to FIG.
Note that Ps in the control flow indicates the low-pressure side pressure, and f indicates the inverter frequency. Further, the predetermined value 1 is in a good operation state in which the low-pressure side pressure is sufficiently lowered, and only the refrigerator that is the outdoor unit is stopped, and the thermo-OFF operation is performed so that the cooler that is the indoor unit is in the blowing operation. The predetermined value 2 is a value that is set to cope with a sudden drop in the low-pressure side pressure, such as when one of the plurality of indoor units has stopped. Here, Ps predetermined value 1, Ps predetermined value 2, target Ps lower limit value, target Ps value, target Ps upper limit value are: Ps predetermined value 1 <Ps predetermined value 2 <target Ps lower limit value ≦ target Ps value ≦ target Ps upper limit There is a value relationship.
Further, the predetermined operation time 1 in the control flow is a time set to prevent excessive operation such that the compressor operates at the maximum output and stops in a short time, and the predetermined operation time 2 is the operation of the compressor. Is a time set to prevent a dull operation where there is a fear of insufficient capability over a long period of time. Here, the predetermined operation time 1 and the predetermined operation time 2 have a relationship of predetermined operation time 1 <predetermined operation time 2.

The refrigeration apparatus starts after the power is turned on in S1, sets the low pressure side pressure to the target Ps lower limit value in S2, sets the comp flag, operation timer, and stop timer to 0, and proceeds to S3. Here, the comp flag is a command for confirming the operation state of the compressor, and is represented by 0 and 1, where 0 indicates stop and 1 indicates operation.
In S3, it is confirmed by the comp flag whether the compressor is in an operating state. If the comp flag is 1, the process proceeds to S4, and if the comp flag is 0, the process proceeds to S5.
In S4, it is determined whether or not the low-pressure side pressure exceeds Ps predetermined value 1, and if so, the process proceeds to S6, and if not, the process proceeds to S7. The predetermined value 1 is an arbitrary value that does not exceed the pressure of the predetermined value 2 at a temperature that is 5 ° C. to 20 ° C. lower than the target low pressure saturation temperature, for example, between 5 ° C. and −50 ° C. The pressure may be selected.
In S6, it is confirmed whether or not the stop timer is 0. If it is not 0, that is, if the compressor is in a stopped state, the process proceeds to S8, and if it is in an operating state, the process proceeds to S10.
In S8, it is determined whether or not the value of the stop timer exceeds a predetermined stop time. If it exceeds, the process proceeds to S9, and if not, the process proceeds to S10. As for the predetermined stop time, an arbitrary time of about 30 minutes may be selected in view of the defrost period and the forced stop period.
In S9, since the compressor has been in a state of being stopped for a long time, the low pressure side pressure is set to the target Ps lower limit value as in the case of turning on the power of S1, the comp flag is set to 1, the stop timer is set to 0, Proceed to S10.
In S10, it is confirmed again by the comp flag whether the compressor is really in operation. If the comp flag is 1, that is, if the compressor is in operation, the process proceeds to S11, and if not, the process proceeds to S12.

In S11, it is determined whether or not the target pressure exceeds Ps predetermined value 2. If it exceeds, the process proceeds to S13, and if not, the process proceeds to an operation time flow starting from S26. Thus, the target Ps can be set not only when the target Ps is stopped, which will be described later, but also when one of the plurality of indoor units stops during operation. Efficient operation can be realized.
Note that the predetermined value 2 is a target between a target low pressure saturation temperature and a temperature lower by 5 ° C. to 20 ° C. than the target low pressure saturation temperature, for example, a pressure corresponding to 10 ° C. to −45 ° C. Any pressure that does not exceed the lower limit of Ps may be selected.
In S12, since the compressor is in a stopped state (comp flag is 0), the target pressure is set to an arbitrary initial value between the target Ps upper limit value and the target Ps lower limit value in order to operate the compressor. Set the timer to 0 and start measuring the operation time.
In S13, it is determined whether or not the value of the operation timer exceeds the predetermined operation time 2. If it exceeds, the process proceeds to S14, and if not, the process proceeds to S18. In addition, about the predetermined operation time 2, what is necessary is just to select arbitrary time about 30 minutes-1 hour.
In S14, since the compressor is in a dull operation and the inside of the freezer is not cooled, the pressure value obtained by reducing the current target Ps by a predetermined value is set as the target Ps. Proceed to For the predetermined value, an arbitrary pressure of about 0.01 MPa may be selected.
In S15, it is determined whether or not the target Ps set in S14 is lower than the target Ps lower limit value. If the target Ps is not lower than the target Ps lower limit value, that is, if appropriate pressure setting is performed, the process proceeds to S16. If not, the process proceeds to S17.
In S17, since it is shown that the target Ps is set to an inappropriate pressure below the target Ps lower limit value, the target Ps is set to the target Ps lower limit value, and the process proceeds to S16.
In S16, since the setting of the pressure value has been changed, the operation timer is reset to 0, and the process proceeds to S18.

In S18, it is determined whether or not the current pressure of the compressor exceeds the target Ps. If it exceeds, the process proceeds to S19, and if not, the process proceeds to S20.
In S19, since it indicates that the freezer is not cold enough, in order to promote the operation of the compressor, the target f is set to a frequency that is increased by a predetermined value from the current target f, and in S23 move on. In addition, about a predetermined value, although depending on the difference with the target value of a low voltage | pressure side pressure, what is necessary is just to set the frequency of about 1 Hz-2 Hz.
In S20, it is determined whether or not the current compressor pressure is lower than the target Ps. If it is low, the process proceeds to S21, and if not, the process proceeds to S22.
In S21, since the inside of the freezer is too cold, in order to suppress the operation of the compressor, the target f is set to a frequency lower than the current target f by a predetermined value, and the process goes to S22. move on. In addition, what is necessary is just to set the arbitrary frequencies similar to S19 about a predetermined value.
In S22, it is determined whether or not an arbitrarily determined predetermined time has elapsed. If the predetermined time has elapsed, the process returns to S3 to set the low pressure side pressure and the inverter frequency again, and the predetermined time has elapsed. If not, the determination in S22 is performed until a predetermined time has elapsed. In addition, about predetermined time, although related to stability of refrigerant | coolant control, what is necessary is just to select arbitrary time between about 30 second-about 1 minute.

Next, a flow that is performed when the low pressure side pressure is equal to or less than the Ps predetermined value 1 during operation will be described.
In S7, although the operation switch is pressed, the low-pressure side pressure is sufficiently lowered, so the target f is set to 0 and the process proceeds to S23.
In S23, it is confirmed again by the comp flag whether the compressor is really in operation. If the comp flag is 1, that is, if the compressor is in operation, the process proceeds to S24, and if not, the process returns to S3.
In S24, the comp flag is set to 0 to stop the operation, the stop timer is started, and the process proceeds to S25.
In S25, it is determined whether or not a predetermined stop time has elapsed after the start of the measurement of the stop timer in S24. If it has elapsed, the process proceeds to S26, and if not, the predetermined time has elapsed. The determination of S25 is performed. As the predetermined stop time, any time required for prohibiting re-operation according to the purpose, such as controlling the restart of the compressor, may be selected.

In S26, it is determined whether or not the value of the operation timer is within the range of the predetermined operation time 1. If it is within the range, the process proceeds to S27, and if it is out of the range, the process proceeds to S28. In addition, about the predetermined operation time 1, what is necessary is just to select the arbitrary time which does not exceed the predetermined operation time 2 in about 5 minutes-about 10 minutes.
In S27, since the low pressure side pressure is sufficiently low in spite of the short operation time, it represents a so-called excessive operation state, so that the pressure value obtained by increasing the current target Ps by a predetermined value to suppress the operation. Is set as the target Ps, and the process proceeds to S29. In addition, about a predetermined value, what is necessary is just to select the arbitrary pressures of about 0.01 MPa similarly to S14.
In S29, it is determined whether or not the target Ps set in S27 exceeds the target Ps upper limit value. If the target Ps is lower than the target Ps upper limit value, that is, if an appropriate pressure is set, the process proceeds to S30. If not, the process proceeds to S31.
Since it is shown in S31 that the target Ps is set to an inappropriate pressure that exceeds the target Ps upper limit value, the target Ps is set to the target Ps upper limit value, and the process proceeds to S30.

In S30, since the setting of the pressure value has been changed, the operation timer is reset to 0, and the process proceeds to S32.
In S32, it is determined whether or not the comp flag is 1 in order to confirm the operation state. If the comp flag is 1, that is, if the compressor is in the operation state, the process proceeds to S22, and if not, the process proceeds to S3. Return.
In S28, it is determined whether or not the value of the operation timer exceeds the predetermined operation time 2,
If so, the process proceeds to S33, and if not, the process proceeds to S30.
In S33, although the low pressure side pressure is low, it indicates that the operation time is excessively longer than necessary. Therefore, in order to promote the operation, the pressure value obtained by lowering the current target Ps by a predetermined value is set to the target Ps. And proceed to S34. In addition, about a predetermined value, what is necessary is just to select the arbitrary pressures of about 0.01 MPa similarly to S14.
In S34, it is determined whether or not the target Ps set in S33 is lower than the target Ps lower limit value. If the target Ps is higher than the target Ps lower limit value, that is, if appropriate pressure setting is performed, the process proceeds to S30. If not, the process proceeds to S35.
In S35, since it is shown that the target Ps is set to an inappropriate pressure below the target Ps lower limit value, the target Ps is set to the target Ps lower limit value, and the process proceeds to S30.

Finally, the flow performed when the comp flag is 0 in S3, that is, when the compressor is in a stopped state, will be described.
In S5, since the operation is stopped, the target f is set to 0 and the process proceeds to S36.
In S36, it is confirmed again by the comp flag whether the compressor is really stopped. If the comp flag is 1, that is, if the compressor is operating, the process proceeds to S37, and if not, the process returns to S3.
In S37, the comp flag is set to 0 to stop the operation, the stop timer is started, and the process proceeds to S38.
In S38, it is determined whether or not a predetermined stop time has elapsed after the start of the stop timer measurement in S37. If it has elapsed, the process returns to S3, and if not, the predetermined time has elapsed. The determination in S38 is performed. In addition, what is necessary is just to select the same arbitrary time as S25 about predetermined stop time.

As described above, the refrigeration apparatus includes the compressor operation time detection means 5 that detects the operation time of the compressor 1, the compressor target operation time setting means 6 that sets the target operation time of the compressor 1, and the compressor operation. Target low pressure side pressure setting means for setting the low pressure side pressure on the suction side of the compressor 1 based on the compressor operation time obtained from the detection value of the time detection means 5 and the set value of the compressor target operation time setting means 6 7, an inverter based on the low pressure side pressure detection means 8 for detecting the low pressure side pressure that is the suction side of the compressor 1, the detected value of the low pressure side pressure detection means 8, and the set value of the target low pressure side pressure setting means 7 Since the inverter control means 9 for driving the device 14 is provided, the inverter device can be operated efficiently.
Therefore, in spite of the fact that the compressor has an inverter device as in the conventional refrigerator, most of the operation time of the compressor is operated by driving the inverter device under the maximum frequency in actual use. Since this is no longer the case, the power consumption of the refrigerator can be reduced.
Further, based on the compressor operating time obtained from the detected value of the compressor operating time detecting means 5 and the set value of the compressor target operating time setting means 6, the detected compressor operating time is compressor target operating time setting means. Since it has a control function of the refrigeration system characterized by controlling the output frequency of the inverter device 14 so that the low-pressure side pressure is lowered when the set value is longer than 6 and the low-pressure side pressure approaches the lower limit value, When starting the operation of the compressor after the compressor has been stopped for a long time, the inverter device can be driven at the maximum frequency so that the low-pressure side pressure approaches the lower limit value.
Furthermore, it is possible to cope with the case where cooling is necessary, such as when the initial operation is started or when the operation is resumed after defrosting.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 3 is a block diagram showing the configuration of the refrigeration apparatus in Embodiment 2 of the present invention. First, the inverter control means 9 is communicatively connected to the inverter average frequency detection means 10 and further connected to the target low pressure side pressure setting means 7 together with the inverter operating frequency range setting means 11. The target low pressure side pressure setting means 7 is connected to the inverter control means 9 together with the low pressure side pressure detection means 8, and the compressor 1 is operated by the inverter device 14 in response to a signal from the inverter control means 9.

Next, the control flow will be described with reference to FIG.
Note that Ps in the control flow indicates the low-pressure side pressure, and f indicates the inverter frequency. Optimum f1 and optimum f2 in the control flow represent an optimum frequency lower limit and an optimum frequency upper limit, respectively, and have an optimum f1 <optimal f2 relationship. The initial target Ps upper limit value represents the target Ps upper limit value assumed when the refrigerator is designed.
After the start of S39, first, in S40, it is confirmed by the comp flag whether the compressor is in an operating state. If the comp flag is 1, the process proceeds to S41, and if the comp flag is 0, the process proceeds to S43. .
In S41, the cumulative operation time of the compressor is calculated from the numerical value of the operation timer, and the cumulative f of the inverter device is calculated by adding the currently set target f to the sum of f before the start of this flow. Thereafter, the process proceeds to S42.
In S42, it is determined whether or not a predetermined time has elapsed in order to suppress accumulation of the accumulation f within the same control cycle. If the predetermined time has elapsed, the process proceeds to S43, and the predetermined time has elapsed. If not, the determination in S42 is performed until a predetermined time has elapsed. In addition, about predetermined time, although related to stability of refrigerant | coolant control, what is necessary is just to select arbitrary time of about 30 seconds-about 1 minute.

In S43, it is determined again whether or not the comp flag is 0. If the operation is stopped and the average f is calculated, the process proceeds to S44, and if the operation is continued, the process returns to S40.
In S44, it is determined whether or not the value of the accumulated f is 0. If the accumulated f is 0, the accumulation of data has just started, or the stopped state continues. The process returns to S40 again, and if not, the process proceeds to S45.
In S45, it is determined whether or not the target Ps is the target Ps upper limit value. If the target Ps is the upper limit value, that is, if control is required, the process proceeds to S46, and if not, the process proceeds to S52.
In S46, an average f for performing the control is calculated, and the process proceeds to S47. Specifically, first, the cumulative operation time calculated in S41 is divided by the predetermined time in S42 to calculate the number of times of frequency accumulation. Thereafter, the average f is calculated by dividing the cumulative f calculated in S41 by the number of times.

In S47, it is determined whether or not the average f is lower than the optimum f1, and if low, the process proceeds to S48, and if not, the process proceeds to S49. Here, the optimum f1 depends on the characteristics of the compressor, but an arbitrary frequency that does not exceed the optimum f2 between about 25 Hz to 30 Hz may be set.
In S48, since the average f is below the optimum f lower limit value, indicating that the inverter device is not operating much, the operation time is shortened, but the operation to increase the inverter frequency during the operation period is promoted. Therefore, the pressure value obtained by lowering the current target Ps upper limit value by a predetermined value is set as the target Ps upper limit value, and the process proceeds to S50. For the predetermined value, an arbitrary pressure of about 0.01 MPa may be selected.
In S50, it is determined whether or not the target Ps upper limit set in S48 is lower than the target Ps lower limit. If lower, the process proceeds to S51, and if not, the process proceeds to S52.
In S51, since it is shown that an inappropriate pressure setting in which the target Ps upper limit value is lower than the target lower limit value is set, the target Ps upper limit value is set as the target Ps lower limit value, and the process proceeds to S52.
In S52, since the setting of the pressure value is changed, the accumulated f is reset to 0, and the process returns to the operation after the start of S40.
In S49, it is determined whether or not the average f exceeds the optimum f2, and if so, the process proceeds to S53, and if not, the process returns to the operation after the start of S40. Here, although the optimum f2 depends on the characteristics of the compressor, an arbitrary frequency between approximately 75 Hz and 80 Hz may be set.
In S53, since the average f exceeds the optimum f upper limit value, which indicates that the inverter device is operating too much, the pressure obtained by increasing the current target Ps upper limit value by a predetermined value in order to suppress the operation. The value is set as the target Ps upper limit value, and the process proceeds to S54. As for the predetermined value, an arbitrary pressure of about 0.01 MPa may be selected as in S48.
In S54, it is determined whether or not the target Ps upper limit set in S53 exceeds the initial target Ps upper limit. If it exceeds, the process proceeds to S55, and if not, the process proceeds to S52.
In S55, the target Ps upper limit value exceeds the initial target Ps upper limit value, and an attempt is made to set a more suppressed operating condition than assumed when the refrigerator was designed. Therefore, the target Ps upper limit value is set to the initial target Ps. Set to the upper limit value and proceed to S52.

As described above, the refrigeration apparatus sets the inverter average frequency detection means 10 that detects the average frequency of the output frequency during operation of the inverter device 14 during the compressor operation time, and the target frequency range of the frequency during operation of the inverter device 14. The inverter operating frequency range setting means 11, the inverter average frequency obtained from the detected value of the inverter average frequency detecting means 10, and the low pressure side pressure which is the suction side of the compressor based on the set value of the inverter operating frequency range setting means 11 Target low pressure side pressure setting means 7, low pressure side pressure detection means 8 for detecting the low pressure side pressure which is the suction side of the compressor, detection value of the low pressure side pressure detection means 8 and target low pressure side pressure setting means 7 Since the inverter control means 9 for driving the inverter device 14 based on the set value of the inverter device 14 is provided, the inverter device can be operated efficiently. It can be carried out.
In particular, it is more efficient to repeat starting and stopping without operating at a certain frequency or lower than continuous operation with a low inverter frequency, so the target is easily achieved by focusing on the upper limit value of the target low pressure. it can.

Embodiment 3 FIG.
FIG. 5 is a block diagram showing a configuration of a refrigeration apparatus according to Embodiment 3 of the present invention. When the low-pressure side pressure is set by the target low-pressure side pressure setting means, the upper limit value and the lower limit of the low-pressure side pressure are set. It is a figure showing that a value is set by the low voltage | pressure side pressure change width setting means.
The inverter control means 9 is communicatively connected to the compressor operating time detecting means 5 and further connected to the target low pressure side pressure setting means 7 together with the compressor target operating time setting means 6. The target low pressure side pressure setting means 7 has a low pressure side pressure change width setting means 12 which sets an upper limit value and a lower limit value of the low pressure side pressure from the outside. The target low pressure side pressure setting means 7 is connected to the inverter control means 9 together with the low pressure side pressure detection means 8, and the compressor 1 is operated by the inverter device 14 in response to a signal from the inverter control means 9.

The control flow is based on the same control flow as in the first or second embodiment except that the target Ps lower limit value and the target Ps upper limit value are set from the outside by the target low pressure side pressure setting means 12. Implemented.

  As described above, the low pressure side pressure change range for setting the upper limit value and the lower limit value for the low pressure side pressure set in the target low pressure side pressure setting means 7 for reducing the low pressure side pressure on the suction side of the compressor 1 by the refrigeration apparatus Since the setting means 12 is provided, it is possible to prevent a reckless operation state that may cause a refrigerator failure, and it is possible to narrow down and set the operation range according to the purpose. Can be suppressed.

Embodiment 4 FIG.
6 is a block diagram showing a configuration of a refrigeration apparatus according to Embodiment 4 of the present invention. When the low-pressure side pressure is set by the target low-pressure side pressure setting means according to claim 2, the upper limit value and the lower limit of the low-pressure side pressure are shown. It is a figure showing that a value is set by the low voltage | pressure side pressure change width setting means.
The inverter control means 9 is communicatively connected to the inverter average frequency detection means 10 and further connected to the target low pressure side pressure setting means 7 together with the inverter operating frequency range setting means 11. The target low pressure side pressure setting means 7 has a low pressure side pressure change width setting means 12 which sets an upper limit value and a lower limit value of the low pressure side pressure from the outside. The target low pressure side pressure setting means 7 is connected to the inverter control means 9 together with the low pressure side pressure detection means 8, and the compressor 1 is operated by the inverter device 14 in response to a signal from the inverter control means 9.

The control flow is based on the same control flow as in the first or second embodiment except that the target Ps lower limit value and the target Ps upper limit value are set from the outside by the target low pressure side pressure setting means 12. Implemented.

  As described above, the low pressure side pressure change range for setting the upper limit value and the lower limit value for the low pressure side pressure set in the target low pressure side pressure setting means 7 for reducing the low pressure side pressure on the suction side of the compressor 1 by the refrigeration apparatus. Since the setting means 12 is provided, it is possible to prevent a reckless operation state that may cause a refrigerator failure, and it is possible to narrow down and set the operation range according to the purpose. Can be suppressed.

It is a block diagram of Embodiment 1 in this invention. It is a control flowchart of Embodiment 1 in this invention. It is a block diagram of Embodiment 2 in this invention. It is a control flow figure of Embodiment 2 in this invention. It is a block diagram of Embodiment 3 in this invention. It is a block diagram of Embodiment 4 in this invention.

Explanation of symbols

1 Compressor 2 Condenser 3 Throttling means 4 Evaporator
5 Compressor operating time detection means
6 Compressor target operating time setting means
7 Target low pressure side pressure setting means
8 Low pressure side pressure detection means
9 Inverter control means
10 Inverter average frequency detection means 11 Inverter operating frequency range setting means 12 Low pressure side pressure change width setting means 13 Refrigerant circuit 14 Inverter device 15 Motor

Claims (3)

In a refrigeration apparatus comprising a refrigerant circuit in which a compressor, a condenser, a throttle means, and an evaporator are communicated with each other by refrigerant piping, and an inverter device having a variable output frequency for driving the compressor,
Compressor operating time detecting means for detecting the operating time of the compressor;
Compressor target operating time setting means for setting the target operating time of the compressor;
Based on the compressor operating time obtained from the detected value of the compressor operating time detecting means and the set value of the compressor target operating time setting means, a target value of the low pressure side pressure which is the suction side of the compressor is set. Target low pressure side pressure setting means,
Low pressure side pressure detecting means for detecting the low pressure side pressure;
Inverter control means for controlling the output frequency of the inverter device based on the detection value of the low pressure side pressure detection means and the set value of the target low pressure side pressure setting means;
A refrigeration apparatus comprising: In a refrigeration apparatus comprising a refrigerant circuit in which a compressor, a condenser, a throttle means, and an evaporator are communicated with each other by refrigerant piping, and an inverter device having a variable output frequency for driving the compressor,
Inverter average frequency detection means for detecting an average output frequency of the inverter device during the compressor operation time;
Inverter operating frequency range setting means for setting a target frequency range of the output frequency of the inverter device;
Target low pressure side pressure setting means for setting a target value of the low pressure side pressure that is the suction side of the compressor based on the detection value of the inverter average frequency detection means and the setting value of the inverter operating frequency range setting means;
Low pressure side pressure detecting means for detecting the low pressure side pressure;
Inverter control means for controlling the output frequency of the inverter device based on the detection value of the low pressure side pressure detection means and the set value of the target low pressure side pressure setting means;
A refrigeration apparatus comprising: 3. The refrigeration apparatus according to claim 1, further comprising low-pressure side pressure change width setting means for externally setting an upper limit value and a lower limit value of the low-pressure side pressure set by the target low-pressure side pressure setting means.

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