JPH0820129B2 - Electric compressor protection device in cooling device - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a cooling device for intermittently operating an electric compressor in a cooling circuit to keep a temperature inside a refrigerator, a freezer, or the like within a predetermined range, and in particular, detects an abnormal operation of the cooling circuit to perform electric compression. The present invention relates to a protective device for an electric compressor in a cooling device, which is provided with a temporary stop means for temporarily stopping the operation of the compressor and then restarting the operation of the compressor.

[Prior art]

Conventionally, this type of device constitutes a cooling circuit by providing a bimetal overload relay device in a power supply path to an electric compressor, as shown in, for example, Japanese Utility Model Laid-Open No. 59-7376. When the load on the electric compressor becomes abnormally large due to an abnormal operation of the cooling circuit, such as clogging of the filter in the condenser and poor lubrication of the electric compressor, the power supply path is turned off and then self-recovering automatically. The electric power supply path is turned on to protect the electric compressor.

[Problems to be Solved by the Invention]

In the above conventional apparatus, if the abnormality in the operation of the cooling circuit is due to a temporary reason, the operation of the electric compressor is automatically restarted in the state where the abnormality disappears.
It is preferable to restart the operation of this electric compressor. However, if the abnormality is not due to a temporary reason, the operation and stop of the electric compressor are repeated for a long time, and the durability of the electric compressor deteriorates. Further, there is a problem that the cooling efficiency is extremely poor and the electric power is wastefully consumed when the electric compressor is repeatedly operated and stopped. The present invention has been made to address the above problems,
The purpose is to improve the durability of the compressor and prevent wasteful consumption of electric power by prohibiting the restarting of the operation of the electric compressor when the abnormal operation of the cooling circuit is not due to a temporary reason. An object of the present invention is to provide a protection device for an electric compressor in a cooling device that is avoided.

[Means for Solving the Problems]

In order to achieve the above object, the structural features of the invention according to claim 1 are the electric compressor (11), the condenser (13),
A cooling circuit that consists of a throttle (14) and an evaporator (15) and circulates the refrigerant that is pressure-fed from the electric compressor through the condenser, the throttle, and the evaporator in this order to cool the inside of the refrigerator, and the temperature inside the refrigerator. And a temperature sensor (31) for detecting the temperature of the inside of the refrigerator detected by the temperature sensor and starting the operation of the electric compressor when the temperature of the inside of the refrigerator detected by the temperature sensor is equal to or higher than the cooling start temperature. When the temperature becomes equal to or lower than the cooling stop temperature, the operation of the electric compressor is stopped, and the cooling control means for maintaining the internal cold storage temperature between the cooling stop temperature and the cooling start temperature by the intermittent operation of the electric compressor (43 , 44,46,4
7) In the cooling device provided with, the operation of the electric compressor is temporarily stopped by detecting an abnormality in the operation of the cooling circuit during the intermittent operation control of the electric compressor by the cooling control means, and then the cooling control is performed. Means (33, 45, 61, 63, 71) for restarting the intermittent operation of the electric compressor by the means, and the intermittent operation control of the electric compressor by the cooling control means during the intermittent operation of the electric compressor by the temporary stop means. Counter means (45,4) that increments the count value each time the operation is stopped and accumulates the number of times of the stop
6) and initialization for returning the count value of the counter means to the initial value when the internal cold storage temperature detected by the temperature sensor becomes equal to or lower than the cooling stop temperature during the intermittent operation control of the electric compressor by the cooling control means. Means (48) and, during the intermittent operation control of the electric compressor by the cooling control means, when the count value by the counter means exceeds a predetermined value, prohibition of restarting the operation of the electric compressor by the temporary stop means The means (45, 68, 69) constitutes a protection device for the electric compressor. Further, the structural feature of the invention according to claim 2 is that the cooling circuit including the electric compressor (11), the condenser (13), the throttle (14) and the evaporator (15) and the temperature sensor (31) described above. ) And cooling control means (43, 44, 46, 47) and defrosting end temperature detecting means (32) for detecting the defrosting end temperature of the evaporator, and the operation of the electric compressor while starting the operation of the electric compressor. The cooling circuit is controlled so as to directly guide the refrigerant pressure-fed from the compressor to the evaporator, and defrosting of the evaporator is started, and the defrosting end temperature detection means detects the defrosting end temperature. In addition, a cooling device having defrosting control means (12, 12a, 24, 51, 52, 54) for stopping the operation of the electric compressor for defrosting, wherein the electric compressor by the defrosting control means is added. The operation of the electric compressor is temporarily stopped by detecting an abnormal operation of the cooling circuit during the operation control of Pause means for resuming the operation of the electric compressor according to the defrosting control means (33,5
(3,61,63,71) and a counter that increases the count value each time the electric compressor is stopped by the temporary stop means during operation control of the electric compressor by the defrost control means and integrates the number of stop times. Means (53, 66) and the operation control of the electric compressor by the defrost control means, in response to the detection of the defrost end temperature by the defrost end temperature detection means, the count value by the counter means to the initial value. During the operation control of the electric compressor by the resetting initialization means (56) and the defrosting control means, when the count value by the counter means becomes larger than a predetermined value, the restarting operation of the electric compressor by the pause means is prohibited. The restart prohibiting means (53, 68, 69) configured to constitute a protection device for the electric compressor in the cooling device.

[Advantageous effects of the invention]

In the invention according to claim 1 configured as described above, in the state where the internal cold storage temperature is normally maintained between the cooling stop temperature and the cooling start temperature due to the intermittent operation of the electric compressor,
When an abnormality occurs in the cooling circuit, the temporary stop means detects an abnormality in the operation of the cooling circuit to temporarily stop the operation of the electric compressor, and then restarts the intermittent operation of the electric compressor by the cooling control means. In this case, if the abnormality of the cooling circuit is due to a temporary reason, the counter means increments the count value each time the electric compressor is temporarily stopped. Since the normal operation starts and the internal temperature falls to the cooling stop temperature, the count value is returned to the initial value by the initialization means. Therefore, in this case, the count value does not increase, and the restart prohibiting means does not prohibit the restart of the operation of the electric compressor by the temporary stopping means, so that the cooling device is returned to the normal cooling operation. On the other hand, if the abnormality of the cooling circuit is not due to a temporary reason, even if the intermittent operation of the electric compressor is restarted, the cooling circuit does not operate normally, so that the internal cold storage temperature does not drop to the cooling stop temperature. Therefore, in this case, the count value is not returned to the initial value by the initialization means, and the count value sequentially increases at each suspension. When the count value becomes larger than the predetermined value, the restart prohibiting means prohibits the restart of the operation of the electric compressor by the temporary stopping means, so that the operation / stop of the electric compressor is not repeated for a long time. Thus, according to the first aspect of the present invention, the operation of the electric compressor is unnecessarily limited if the abnormality of the cooling circuit that occurs while cooling the inside of the refrigerator is due to a temporary reason. If the abnormality is not due to a temporary reason, the electric compressor will not be repeatedly operated and stopped for a long time, improving the durability of the electric compressor and reducing the amount of power consumed. You can avoid consumption. Further, in the invention according to claim 2, defrost control means for removing frost attached to the evaporator is added to the cooling device. This defrost control means, until the defrost end temperature of the evaporator is detected by the defrost end temperature detection means, drives the electric compressor to directly guide the refrigerant pressure-fed from the electric compressor to the evaporator, Warm the evaporator to remove the frost adhering to it. If an abnormality occurs in the cooling circuit during the defrosting control, the temporary stop means detects an abnormality in the operation of the cooling circuit to temporarily stop the operation of the electric compressor, and then the defrosting control means stops the operation of the electric compressor. Restart the operation. Also in this case, if the abnormality of the cooling circuit is due to a temporary reason, the counter means increments the count value each time the electric compressor is stopped, but when the operation of the electric compressor is restarted, the cooling circuit is normal. Then, the temperature of the evaporator rises to the defrosting end temperature, so that the count value is returned to the initial value by the initialization means. Therefore, in this case, the count value does not increase, and the restart prohibition means does not prohibit the operation restart of the electric compressor by the temporary stop means, so that the cooling device is returned to the normal defrosting operation. on the other hand,
If the abnormality of the cooling circuit is not due to a temporary reason,
Even when the operation of the electric compressor is restarted, the evaporator does not rise to the defrosting end temperature because the cooling circuit does not operate normally. Therefore, in this case, the count value is not returned to the initial value by the initialization means, and the count value sequentially increases at each suspension. When the count value becomes larger than the predetermined value, the restart prohibiting means prohibits the operation restarting of the electric compressor by the temporary stopping means.
The operation / stop of the electric compressor will not be repeated for a long time. Thus, according to the second aspect of the invention, the operation of the electric compressor is unnecessarily limited if the abnormality of the cooling circuit that occurs during defrosting of the evaporator is due to a temporary reason. If the abnormality is not due to a temporary reason, the electric compressor will not be repeatedly operated and stopped for a long time, which will improve the durability of the electric compressor and reduce waste. Power consumption can also be avoided.

【Example】

An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing a cooling device for cooling the inside of a refrigerator or a freezer. This cooling device includes an electric compressor 11, a four-way valve 12, a condenser 13, a throttle 14, and an evaporator 15 which form a cooling circuit.
The electric compressor 11, the four-way valve 12, the condenser 13, and the throttle 14 are provided outside the refrigerator or the freezer, and the evaporator 15 is provided inside the refrigerator or the freezer. An electromagnetic solenoid 12a is incorporated in the four-way valve 12, and when the solenoid 12a is not energized, the four-way valve 12 is set to the first state (illustrated state), and the refrigerant pressure-fed from the electric compressor 11 is indicated by a solid arrow direction. The inside of the refrigerator is cooled by the evaporator 15. When the electromagnetic solenoid 12a is energized, the four-way valve 12 is switched to the second state and the electric compressor 11
The refrigerant pumped from is circulated in the direction of the broken line arrow to defrost the evaporator 15. Electric power is supplied to the electric compressor 11 via the power supply lines L1 to L3, and these power supply lines L1 to L3 are supplied.
A main switch 21 that is turned on / off by a user's operation, and an electromagnetic contactor 22 that is turned on by energizing the coil 22a and turned off by releasing the energization are interposed between the main switch 21 and the main switch 21. Electromagnetic solenoid 12a of the coil 22a and the four-way valve 12 of the electromagnetic contactor 22 is connected between the power supply line L1, L3 via the normally open contacts x _1, x ₂ of the relay 23, the normally open contact x _1, x ₂ is designed to off by energization and non-energization of the coil X _1, X ₂ of the relay 23. Energization / de-energization of the coils X ₁ and X ₂ of the relays 23 and 24 is controlled by an electric control circuit 25, which is connected to the power supply lines L2 and L3 via a power transformer 26. The direct-current voltage subjected to the AC-DC conversion is supplied from the supplied power circuit 27. The electric control circuit 25 is composed of a microcomputer or the like having a timer 25a built therein. The circuit 25 normally executes a "main program" corresponding to the flowchart of FIG. The "defrost control program" corresponding to the flowchart in the figure is executed. The timer 25a generates an interrupt signal several hours after reset. An internal temperature sensor 31, an evaporator temperature switch 32, a case temperature switch 33, a buzzer 34, and an indicator 35 are connected to the electric control circuit 25. The inside temperature sensor 31 is provided in the inside of a refrigerator or a freezer and detects the inside temperature T ₁ to detect the same temperature.
The detection signal representing T ₁ is output. The evaporator temperature switch 32 is composed of a temperature sensitive switch attached to the evaporator 15, and starts to turn on when the evaporator temperature T ₂ reaches the defrosting end temperature T _2H . The case temperature switch 33 is composed of a temperature sensitive switch attached to the case of the electric compressor 11, and when the case temperature T ₃ reaches the operation stop temperature T _3H , the case temperature switch 33 starts to turn on, and when the case temperature T ₃ is the same, the case temperature T _{3 Turns} off when the temperature reaches the operation restart temperature T _3L (T _3H > T _3L ). The buzzer 34 and the indicator 35 inform the user of an abnormality in the cooling circuit. Next, the operation of the embodiment configured as described above will be described with reference to flowcharts. When the user turns on the main switch 21, the power circuit 27
DC voltage starts to be supplied to the electric control circuit 25 from the
25 starts the execution of the "main program" at step 40 and executes the initial setting process at step 41. In this initialization processing, the suspension flag STP is initialized to "0" and the count value N is initialized to "0". In addition, the suspension flag STP indicates whether or not the abnormality of the cooling circuit is detected.
It is set to "1" when an abnormality is detected, and is set to "0" when no abnormality is detected. The count value N represents the number of times the abnormality is detected. In addition, in this initial setting process, the coils X ₁ and X ₂ of the relays 23 and 24 are de-energized, the buzzer 34 is set to the non-sounding state, and the timer 25a is reset. By controlling the de-energization of these coils X ₁ and X ₂ , normally open contacts of relays 23 and 24
Since x ₁ and x ₂ are set to the off state, the coil 22a and the electromagnetic solenoid 12a are not energized. As a result, the electromagnetic contactor 22 is set to the off state and electric power is not supplied to the electric compressor 11, so that the compressor 11 is maintained in the stopped state.
Further, the four-way valve 12 is maintained in the first state (state shown in the figure). After the initialization processing, the program proceeds to step 42, and thereafter, the electric control circuit 25 repeatedly executes the circulation processing including steps 42 to 48. In this circulation process, the electric control circuit 25
At 42, a detection signal is fetched from the internal temperature sensor 31, and at step 43, it is determined whether the internal temperature T ₁ represented by the detection signal is equal to or higher than the cooling start temperature T _1H . in this case,
If the internal temperature T ₁ is equal to or higher than the cooling start temperature T _1H (time t ₀ , t ₂ , t ₄ , t _{6 in} FIG. 5A), it is determined to be “YES” in step 43,
Since at step 44 begins to energize the coil coil X ₁ of the relay 23, normally open contacts x ₁ of the relay 23 is turned on, the coil 22a
Is energized. As a result, the electromagnetic contactor 22 is set to the ON state, so that the electric compressor 11 starts operating and starts pumping the refrigerant to the four-way valve 12. Now, since the four-way valve 12 is set to the first state, the refrigerant pressure-fed from the electric compressor 11 circulates in the direction of the solid arrow, and the evaporator 15 starts cooling the inside of the refrigerator. After the processing of step 44, through the processing of the "abnormality check routine" of step 45 described later, the program is returned to step 42, after the detection signal representing the internal temperature T ₁ in step 42 is fetched, and then to step 43. It is again determined whether the internal temperature T ₁ is the cooling start temperature T _1H or higher. Now, since the inside temperature T ₁ starts to decrease due to the start of the cooling, based on the determination of “NO” in step 43, that is, the inside temperature T ₁ is less than the cooling start temperature T _{1H, the} inside of the chamber is judged to be 46 in step 46. It is determined whether the internal temperature T ₁ is the cooling stop temperature T _1L or less. In this case, if the internal temperature T ₁ is not sufficiently lowered and is higher than the cooling stop temperature T _1L , step 4
Based on the determination of “NO” in 6, the electric control circuit 25 continues to repeatedly execute the circulation process including steps 42, 43, 46 and 45. At this time, the internal temperature T ₁ gradually decreases due to the cooling (time t _{0 to} t ₁ , t _{2 to} t ₃ , t _{4 to} t ₅ , t _{6 to} t in FIG. 5A).
₇ ). During the circulation process, when the internal temperature T ₁ becomes lower and becomes equal to or lower than the cooling stop temperature T _1L (time t ₁ , t ₃ , t _{5 in} FIG. 5A), the electric control circuit 25 determines “YES” in step 46. It determined that "since releasing the energization of the coil X ₁ of the relay 23 at step 47, the normally open contacts x ₁ of the relay 23 is turned off, is released energization of the coil 22a. As a result, the electromagnetic contactor 22 is set to the off state, the electric compressor 11 stops operating, and the pressure supply of the refrigerant is stopped, so that the cooling of the inside of the refrigerator by the evaporator 15 is stopped. After the processing of step 44, the program is returned to step 42 through the processing of the "abnormality check routine" of step 45, and the electric control circuit 25 proceeds to step 42 as described above.
After capturing the detection signal representing the internal temperature T ₁ in step S43, it is determined in step 43 whether the internal temperature T ₁ is _{equal to} or higher than the cooling start temperature T _1H , and in step 46 the internal temperature T ₁ Is below the cooling stop temperature T _1L . In this case, due to the cooling stop, the internal temperature T ₁ gradually increases from the cooling stop temperature T _1L , so that the step 43,
On the basis of the judgment of "NO" in "46", "NO", the electric control circuit 25 starts to continue to execute the circulation process consisting of steps 42, 43, 46, 45 again (time t _{1 to} t in FIG. 5A). ₂ , t ₃ ~ t ₄ ,
t _{5 to} t ₆ ). Then, the internal temperature T ₁ is the cooling start temperature again.
When it becomes equal to or higher than T _1H (time t ₀ , t ₂ , t ₄ , t _{6 in} FIG. 5A), the electric control circuit 25 starts the operation of the electric compressor 11 as described above, and such a compressor is started. 11 intermittent operation, the temperature inside
T ₁ is held between the cooling start temperature T _1H and the cooling stop temperature T _1L . During such intermittent operation of the electric compressor 11, the electric control circuit 25 checks the abnormality of the operation of the cooling circuit by the processing of the "abnormality check routine" of step 45 described above. The details of this "abnormality check routine" are shown in FIG. 4, and the electric control circuit 25 starts the execution of the routine at step 60, and at step 61 whether the case temperature switch is turned on or not. To judge. In this case, if there is no abnormality in the cooling circuit consisting of the electric compressor 11, the four-way valve 12, the condenser 13, the throttle 14, and the evaporator 15, the temperature of the case of the electric compressor 11 does not become so high and the case temperature Since the switch 33 is off, the electric control circuit 25 determines “NO” in step 61, and “NO” in step 70 based on the temporary stop flag STP initially set to “0”. Then, in step 75, the execution of the "abnormality check routine" is ended and the "main program" is started to be executed. With this, if there is no abnormality in the cooling circuit,
No substantial process is performed in the "abnormality check routine". On the other hand, if the return of the lubricating oil in the electric compressor 11 is bad or the filter in the condenser 13 is clogged, the load on the electric compressor 11 increases and the amount of heat generated by the compressor 11 increases. The case temperature T ₃ of the compressor 11 becomes high. Further, if the refrigerant in the cooling circuit leaks from any place, the amount of the refrigerant returned to the electric compressor 11 is reduced, and the cooling action of the circulating refrigerant of the electric compressor 11 is cut off, so that the electric compressor 11
The case temperature T ₃ becomes higher. Due to the abnormal operation of the cooling circuit as described above, the case temperature T ₃ becomes high during the operation of the electric compressor 11, and the operation stop temperature increases.
When T _3H is reached and the case temperature switch 33 is turned on (5A
At times t ₇ , t ₉ , t _{11 in the} figure), the electric control circuit 25 determines “YES” in step 61, and determines “0” in step 62.
It is determined that based on the pause flag STP that is set "YES" in to release the energization of coil X ₁ of the relay 23 at step 63. As a result, as described above, the electromagnetic contactor
22 is turned off, electric power is no longer supplied to the electric compressor 11, and the compressor 11 is temporarily stopped. After the processing of step 63, the electric control circuit 25
At 64, energization of the buzzer 34 is started, and at step 65, an error display control signal is output to the display 35. As a result, the buzzer 34 starts sounding and the display 35 displays an error indicating that an abnormality has occurred in the cooling circuit.
The user can recognize the abnormality. Next, the electric control circuit 25 adds "1" to the count value N in step 66, sets the temporary stop flag STP to "1" in step 67, and sets the count value N to a predetermined value in step 68. Value N
It is determined whether or not it is larger than _MAX (for example, set to about "3" or "4"). If the count value N is equal to or less than the predetermined value N _MAX , the electric control circuit 25 determines “NO” in step 68,
Return the program to step 61. In this case, if not much time has passed since the electric compressor 11 was stopped and the case temperature switch 33 is still in the ON state, the electric control circuit 25 determines “YES” in step 61 as in the above. However, since the suspension flag STP is set to "1",
Based on the judgment of “NO” in step 62, step 6
The cyclic process consisting of 1,62 is repeatedly executed. During this time, since the electric compressor 11 is stopped, is cooled by the outside air case temperature T ₃ of the compressor 11 gradually decreases (in FIG. 5A time _{t 7 ~t 8, t 9 ~t} 10, t _{11 to} t ₁₂ ). In this way, when the case temperature T ₃ naturally decreases to the operation restart temperature T _3L (time t ₈ , t ₁₀ , t _{12 in} FIG. 5A),
Since the case temperature switch 33 is turned off, the electric control circuit 25 that is executing the circulation process determines “NO” in step 61, and also determines the temporary stop flag STP set to “1” in step 70. On the basis of the above, "YES" is determined, the processing including steps 71 to 74 is executed, and the execution of the "abnormality check routine" is ended in step 75. In step 71, energization of the coil X ₁ of the relay 23 is started, the electromagnetic contactor 22 is turned on again, and the temporarily stopped electric compressor 11 is restarted. Buzzer 34 in step 72
Is controlled to stop, and in step 73, the display 35
The error display of is controlled to stop. Further, in step 74, the suspension flag STP is changed to "0". After executing such an "abnormality check routine", the electric control circuit 25 again returns to the "main program" (Fig. 2).
Is executed to start the intermittent operation of the electric compressor 11 described above. In this case, if the abnormality of the cooling circuit is temporary and disappears, the normal intermittent operation of the electric compressor 11 is restarted. This normal restart of the intermittent operation means that the internal temperature T ₁ reaches the cooling stop temperature T _1L by the operation of the electric compressor 11 (time t _{13 in} FIG. 5A), and in this case, , The steps of the "main program" (Fig. 2)
Based on the determination of "YES" in 46, the count value N is initialized to "0" by the process of step 48.
Even if the count value N is increased by "1" by the process of step 66 (FIG. 4) each time the cooling circuit is determined to be abnormal in the "abnormality check routine", the same value N does not increase so much. It is never judged as “YES” at 68. As a result, in this case, assuming that the abnormality of the cooling circuit is removed, the cooling device automatically returns to the normal operation operation. On the other hand, if the abnormality of the cooling circuit is not temporary,
Normal intermittent operation of the electric compressor 11 is not restarted and
T ₁ does not reach the cooling stop temperature T _1L . Therefore, the count value N is not initialized to "0" by the processing of step 48 of the "main program" (Fig. 2), and the above-mentioned operation is performed every time the cooling circuit is judged to be abnormal in the "abnormality check routine". By the processing of step 66 (FIG. 4), the count value N increases by "1", and the same value N exceeds the predetermined value N _MAX . As a result, it is determined to be “YES” in step 68 and the execution of all the programs is stopped in step 69, so that the electric compressor 11 is maintained in the stopped state and the buzzer is activated.
While 34 continues to sound, the display 35 maintains an error display. In this state, the user can
Unless 21 is turned off and then turned on, the execution of the “main program” is not started and the operation of the electric compressor 11 is not restarted. As a result, the operation / stop of the electric compressor 11 is not repeated for a long time, the durability of the compressor 11 is improved, and unnecessary power consumption can be avoided.
Further, the user can always recognize the abnormality of the cooling circuit by the buzzer 34 and the display 35. When several hours have passed since the start of operation of the cooling device,
The timer 25a generates an interrupt signal, and the electric control circuit 25, which is executing the "main program", starts executing the "defrost control program" of FIG. The energization of the coils X ₁ and X ₂ of 24 and 24 is started. As a result, the normally open contacts x ₁ and x _{2 of} the relays 23 and 24 are turned on, and the coil 22a and the electromagnetic solenoid 12a are energized and controlled, so that the electromagnetic contactor 22 is turned on and electric power is supplied to the electric compressor 11. At the same time, the four-way valve 12 is switched to the second state (time t ₀ , t _{2 in} FIG. 5B). In this state, the electric compressor 1
Refrigerant pumped from 1 circulates in the direction of the dashed arrow,
Since 5 generates heat, frost attached to the evaporator 15 starts to be removed. After the processing of step 51, the electric control circuit 25
At 52, it is determined whether the evaporator temperature switch 32 is in the on state. Now, after the defrosting has started, if not much time has passed, the electric control circuit 25 continues to repeatedly execute the circulation processing of steps 52 and 53 based on the determination of "NO" in step 52. The processing of this step 53 is the above-mentioned "abnormality check routine", and as described above, if there is no abnormality in the cooling circuit, substantial processing is not performed in this routine. Since the evaporator 15 continues to generate heat during such circulation processing, the evaporator temperature T ₂ gradually rises, and the frost attached to the evaporator 15 is removed. On the other hand, during the circulation process, when the evaporator temperature T ₂ reaches the defrosting end temperature T _2H at which defrosting is completed (time t ₁ and t _{9 in} FIG. 5B), the evaporator temperature switch 32 is turned on, so The control circuit 25 determines "YES" in step 52, and executes steps 54 to 5
After the process of 6, the execution of the "defrost control program" is terminated in step 57, and the suspended "main program" is executed.
Start executing (Fig. 2) again. In step 54, the coil X ₂ of the relay 24 is de-energized, so the normally open contact x ₂ of the relay 24 is turned off to de-energize the electromagnetic solenoid 12a and the four-way valve 12 is returned to the first state. . As a result, thereafter, the refrigerant pressure-fed from the electric compressor 11 circulates in the direction of the solid arrow, and the evaporator 15 starts cooling the inside of the refrigerator as described above. In step 55, the timer 25a is reset,
The timer 25a starts measuring time again from the beginning. Then, after several hours have passed from the start of the measurement, the timer
25a generates an interrupt signal again, and the electric control circuit 2
5 again executes the "defrost control program".
Further, in step 56, the count value N is initialized to "0". On the other hand, during the defrosting control, when an abnormality occurs in the cooling circuit, the electrical control circuit 25 executes the same "abnormality check routine" processing as in the case of the cooling control described above. The operation of the electric compressor 11 is temporarily stopped, and thereafter, the operation of the compressor 11 is automatically restarted in cooperation with the case temperature switch 33 (time t ₂ to time in FIG. 5B).
t ₈ ). In this case also, the anomaly is temporary and
If the cooling circuit returns to normal, the evaporator temperature T ₂ will be the defrost end temperature.
The evaporator temperature switch 33 is turned on upon reaching T _2H (see time t _{9 in} FIG. 5B), and the count value N is initialized to “0” by the process of step 56, so that the same value N becomes too large. The cooling device automatically returns to normal operation. Further, when the abnormality of the cooling circuit is not temporary, the count value N is not initialized to "0" as described above, and the same value N becomes large.
"YES" in the figure), that is, the count value N is the predetermined value N
_When it is determined that it is larger than _MAX , execution of all programs is stopped in step 69. Thereby, as described above, the electric compressor 11 is maintained in the stopped state, and the compressor 11
It is possible to improve the durability of, and avoid unnecessary power consumption. In the above embodiment, the abnormality of the cooling circuit is detected based on the temperature of the case of the electric compressor 11,
As shown by a broken line in FIG. 1, an overload relay 37 constituted by a bimetal as shown in Japanese Utility Model Laid-Open No. 59-7376 cited in the above-mentioned section of the prior art is provided with an electric power supply line L1 to L1 of the electric compressor 11.
The overload of the compressor 11 may be directly detected by interposing it in L3. Also in this case, when the load of the electric compressor 11 is increased due to the clogging of the filter in the condenser 13, the lubrication failure of the electric compressor 11, etc. The load relay 37 is turned off, the power supply to the electric compressor 11 is cut off, and the operation of the compressor 11 is temporarily stopped. Also, after that, when the temperature of the bimetal decreases due to the interruption of the power supply,
The overload relay 37 is turned on, power supply is restarted, and the electric compressor 11 restarts operation. In this case also, the number of times the overload relay 37 is operated is determined by the step 66 (fourth
Make sure to count as shown in the figure. Further, as shown by the broken line in FIG. 1, a pressure sensor 38 is provided in the passage of the refrigerant that is pressure-fed from the electric compressor 11, and the pressure in the passage is detected to cause a refrigerant leak and a filter in the condenser 13. An abnormality in the cooling circuit due to clogging of the cooling circuit may be detected. In this case, when the pressure detected by the pressure sensor 38 is abnormally low or abnormally high in step 61 (FIG. 4) of the above-described embodiment, it is determined that the cooling circuit is abnormal, and steps 62 to 62 are performed. After performing the process of 68 and once detecting the abnormality, the processes of steps 70 to 74 may be performed after a predetermined time.

[Brief description of drawings]

FIG. 1 is a block diagram of a cooling device according to an embodiment of the present invention, FIGS. 2 to 4 are flow charts of a program executed by the electric control circuit of FIG. 1, and FIGS. 5A and 5B are the above. It is a time chart showing operation of a cooling device. Explanation of symbols 11 …… Electric compressor, 12 …… Four-way valve, 13 …… Condenser, 14…
… Squeezer, 15 …… Evaporator, 22 …… Magnetic contactor, 23,24 ……
Relay, 25 ... electric control circuit, 31 ... internal temperature sensor,
32 …… Evaporator temperature switch, 33 …… Case temperature switch, 37 …… Overload relay, 38 …… Pressure sensor.

Claims (2)

[Claims] 1. A cooling system comprising an electric compressor, a condenser, a throttle and an evaporator, in which a refrigerant pumped from the electric compressor is circulated through the condenser, the throttle and the evaporator in this order to cool the inside of the refrigerator by the evaporator. A circuit, a temperature sensor for detecting the temperature inside the refrigerator, and the operation of the electric compressor is started when the temperature inside the refrigerator detected by the temperature sensor becomes equal to or higher than the cooling start temperature,
And when the temperature inside the refrigerator detected by the temperature sensor becomes equal to or lower than the cooling stop temperature, the operation of the electric compressor is stopped, and the temperature inside the refrigerator is stopped by the intermittent operation of the electric compressor. In a cooling device having a cooling control means held between the electric compressor and the cooling control means, the operation of the electric compressor is temporarily stopped by detecting an abnormality in the operation of the cooling circuit during the intermittent operation control of the electric compressor by the cooling control means. Then, the temporary stop means for restarting the intermittent operation of the electric compressor by the cooling control means, and the intermittent operation control of the electric compressor by the cooling control means,
During the intermittent operation control of the electric compressor by the cooling control means, a counter means for increasing the count value every time the electric compressor is stopped by the temporary stop means and integrating the number of times of stop,
Initializing means for returning the count value of the counter means to an initial value when the internal cold storage temperature detected by the temperature sensor becomes equal to or lower than the cooling stop temperature, and intermittent operation control of the electric compressor by the cooling control means,
And a restart prohibition means for prohibiting the restart of the intermittent operation of the electric compressor by the temporary stop means when the count value by the counter means becomes larger than a predetermined value, and the protection of the electric compressor in the cooling device. apparatus. 2. A cooling system comprising an electric compressor, a condenser, a throttle and an evaporator, in which a refrigerant pumped from the electric compressor is circulated through the condenser, the throttle and the evaporator in this order to cool the inside of the refrigerator by the evaporator. A circuit, a temperature sensor for detecting the temperature inside the refrigerator, and the operation of the electric compressor is started when the temperature inside the refrigerator detected by the temperature sensor becomes equal to or higher than the cooling start temperature,
And when the temperature inside the refrigerator detected by the temperature sensor becomes equal to or lower than the cooling stop temperature, the operation of the electric compressor is stopped, and the temperature inside the refrigerator is stopped by the intermittent operation of the electric compressor. Cooling control means held between the defrosting end temperature detecting means for detecting the defrosting end temperature of the evaporator, a refrigerant to be pressure-fed from the electric compressor while starting the operation of the electric compressor. Defrosting the electric compressor in response to the detection of the defrosting end temperature by the defrosting end temperature detection means by controlling the cooling circuit so as to directly lead to the evaporator and starting the defrosting of the evaporator. In a cooling device provided with a defrost control means for stopping the operation for, the operation of the electric compressor is detected by detecting an abnormality in the operation of the cooling circuit during the operation control of the electric compressor by the defrost control means. Pause it A temporary stop means for restarting the intermittent operation of the electric compressor by the defrost control means later, and a count value for each operation stop of the electric compressor by the temporary stop means during the operation control of the electric compressor by the defrost control means. And a counter unit that integrates the number of stoppages by increasing the number of stop times, and the counter unit in response to the detection of the defrosting end temperature by the defrosting end temperature detecting unit during the operation control of the electric compressor by the defrosting control unit. Initializing means for returning the count value to an initial value, and operation of the electric compressor by the temporary stopping means when the count value by the counter means becomes larger than a predetermined value during operation control of the electric compressor by the defrosting controlling means. A protection device for an electric compressor in a cooling device, which is provided with a restart prohibition means for prohibiting restart.