JPH0612198B2 - Refrigeration system operation controller - Google Patents

Description

TECHNICAL FIELD The present invention relates to an operation control device for a refrigerating device provided in a prefabricated refrigerator or the like, and particularly controls the frequency of AC power supplied to a compressor of the refrigerating device. The present invention relates to an operation control device for a refrigeration system including an inverter.

(B) Conventional technology For example, in Japanese Utility Model Laid-Open No. 59-150990, the natural frequency of a product equipped with a variable speed compressor and its higher natural frequencies are stored in a control unit, and each frequency is stored. A variable-speed compressor rotation speed control device is disclosed in which, in a corresponding rotation speed and a rotation speed range of a certain width before and after the rotation speed, the rotation speed is transiently passed but is not fixedly rotated. There is.

(E) Problems to be Solved by the Invention In the above conventional technology, when the compressor rotation speed changes, when the natural frequency and the high-order natural frequency are passed,
Although the vibration or resonance occurs in the product due to the vibration of the compressor for a short period of time, the number of occurrences of the resonance also increases with the use of the product for a long period of time, and due to the resonance, the pipes of the product are joined. There has been a problem that a failure such as cracking occurs in a part. Also, when a compressor with a large capacity is used, resonance continues even after the compressor rotation speed gradually decreases to pass the natural frequency and the higher natural frequency, causing the failure of the refrigeration system. become. Furthermore, when the compressor rotation speed gradually rises to pass the natural frequency and the high-order natural frequency, it takes a short time, and resonance does not continue after the passage. If the operation is stopped, the increase in the refrigerating capacity is delayed, and the compressor is often operated, stopped, or started and stopped, which may cause a failure of the compressor or a switch for controlling the power supply to the compressor. There is a problem that The present invention aims to solve the above problems.

(D) Means for Solving the Problems The present invention has been made for the purpose of solving the above problems, and will be described based on the following examples, by inputting a signal from the temperature sensor (24). From a controller (21) that outputs a frequency signal, an inverter (22) that inputs the frequency signal and outputs frequency-controlled power and a refrigeration system (2)
The controller (21) installed between the compressor (5) and
The frequency signal from the inverter gradually increases, and the inverter (22)
When the frequency of the electric power from the compressor to the compressor (5) reaches the resonance frequency of the refrigeration system (2), the power is continuously turned on, the frequency signal from the controller (21) gradually decreases, and the inverter (22) compresses it. A magnet switch (23) that is turned off based on a signal from the controller (21) when the frequency of electric power to the machine (5) becomes equal to or lower than the resonance frequency of the refrigeration system (2) or a frequency slightly higher than this resonance frequency. An operation control device for a provided refrigeration system is provided.

(E) Operation In the following, according to the embodiment, when the frequency signal from the controller (21) rises to the resonance frequency, for example, when the compressor (5) starts to operate, the magnet switch (23). Continue the operation without turning off the refrigerator (4)
The refrigerating capacity of immediately increases. When the compressor (5) is stopped, the frequency signal from the controller (21) drops, and the frequency T is slightly higher than the resonance frequency THz of the refrigeration system (2).
When it becomes + ΔHz, the controller (21) outputs a signal to the magnet switch (23) between the inverter (22) and the compressor (5), and this magnet switch is turned off to the compressor (5). The power supply is forcibly stopped, and the compressor (5) is prevented from operating at the resonance frequency.

(F) Embodiment Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

A prefabricated refrigerator (1) shown in FIG. 2 is provided with a refrigerating device (2) on one side wall of the prefabricated refrigerator. The refrigeration system (2) consists of an external unit (3) and an internal unit (4) .The external unit (3) is divided by a partition plate (3B) into an upper heat exchange chamber (3C) and a lower machine chamber (3D). ) And a heat exchange room (3C)
A condenser (6) that constitutes a refrigeration cycle, an axial-flow type condenser blower (7), and the like are disposed in this. In addition, the machine room (3
In D), the compressor (5) and the like that constitute the refrigeration cycle are arranged. Further, in the in-compartment unit (4), an evaporator (8) and a blower for the evaporator (9) which constitute a refrigeration cycle together with a compressor (5) and the like
The air is circulated outside and inside the refrigerating device (2) as shown by the arrows by operating the blowers (7) and (9). Incidentally, (4A) is a drain pan, and (4B) is a drain pipe.

Further, FIG. 1 shows a schematic block circuit diagram of a compressor operation control device, (21) shows a controller constituted by a microcomputer, (22) shows an inverter, and (23) shows a magnet switch. (23) is the controller (2
Turns on and off based on the signal from 1). The same reference numerals as in FIG. 2 are the same. Further, (24) is a temperature sensor provided in a suitable place of the prefabricated refrigerator (1), for example, near the cool air suction port of the evaporator (5), and is connected to the controller (21).

The operation of the operation control device will be described below. The controller (21) normally inputs the temperature signal sensed by the temperature sensor (24) and performs PID control based on the temperature signal between the resonance frequency THz of the refrigeration system (2), for example, between 30 Hz and 60 Hz higher than 25 Hz. The frequency signal is output to the inverter (22). Here, in order to carry the item into the prefabricated refrigerator (1), when the outside air enters the inside of the refrigerator and the temperature inside the refrigerator rises due to the increase of the cooling load due to the item, the temperature sensor (24) indicates the temperature. And outputs a temperature signal. Based on the temperature signal, the controller (21) gradually increases and outputs the frequency signal, and the frequency of the power supplied to the inverter (22) to which the frequency signal is input gradually increases. For this reason, the frequency of the electric power input to the compressor (5) increases, the cooling capacity of the compressor (5) gradually increases, and the rise in the temperature inside the refrigerator stops, and thereafter, the carrying-in work etc. is completed. When the cooling load decreases, the temperature inside the refrigerator gradually decreases.

When the internal temperature gradually decreases as described above, the temperature sensor (24) senses the decreased temperature and the temperature signal is controlled by the controller (21).
Output to. Then, it outputs to the controller (21). Then, the controller (21) gradually reduces and outputs the frequency signal, and the frequency of the power supplied to the inverter (22) to which the frequency signal is input gradually decreases. Because of this, the compressor
The frequency of the electric power input by (5) decreases, and the cooling capacity of the compressor (5) gradually decreases. After that, if the internal cold storage temperature continues to decrease due to the reduction of the cooling load despite the reduction of the cooling capacity, the frequency signal output from the controller (21) further decreases. Then, after the controller (21) outputs the frequency T + ΔHz, for example 28 Hz, which is slightly higher than the resonance frequency THz of the refrigeration system (2), the controller (21) outputs a stop signal of the compressor (5), that is, a magnet switch ( The off signal of 23) is output, the magnet switch 23 is turned off, and the energization of the compressor 5 is stopped as shown in FIG. If the frequency at which resonance occurs in the refrigeration system (2) is, for example, between 22 Hz and 25 Hz, and if resonance is extremely small at 25 Hz in this resonance frequency range, the controller (21) will cause
It is also possible to output Hz and immediately turn off the magnet switch (23) to stop the energization of the compressor (5). Thereafter, when the temperature inside the refrigerator rises due to the stop of the compressor (5), the frequency signal from the controller (21) immediately rises to 30 Hz and the magnet switch (23) turns on.

Also, when the operation of the refrigeration system (2) is stopped, for example, the maximum operating frequency from the controller (21) is, for example, close to 60 Hz
When the magnet switch (23) is turned off while the frequency signal of 8 Hz is being output, an arc or the like is generated in this magnet switch, which causes malfunction of the controller (21). Therefore, when stopped, the frequency signal from the controller (21) is gradually lowered, and when the frequency reaches 28 Hz, the controller (21) outputs an off signal to the magnet switch (23) to cause resonance in the refrigeration system (2). The magnet switch (23) is turned off to stop the power supply to the compressor (5) and stop the operation at a frequency that does not cause the controller (21) to malfunction due to the above arc or the like. . After that, when starting the operation of the compressor, the magnetic switch (2
3) is turned on, the frequency signal from the controller (21) rises from zero Hz to the target frequency, and the frequency of the electric power supplied from the inverter (22) to the compressor (5) also rises rapidly. As shown in the figure, electric power is continuously supplied to the compressor (5), and the supplied electric power increases as the frequency increases. In addition, since the rising speed is fast when the frequency rises,
The resonance frequency is passed in a short time, and as a result, the resonance of the refrigeration system (2) at the resonance frequency is not a problem.

Therefore, when starting the operation of the compressor (5), etc., even if the frequency from the controller (21) rises to the resonance frequency, the power supply to the compressor (5) continues and the refrigerating capacity is quickly increased. Can rise to, and also when the frequency rises the compressor
Starting and stopping of (5) can be avoided, and failure of the compressor (5) or the magnet switch (23) can be prevented.
Further, for example, the frequency signal from the controller (21) is used as a refrigeration system for controlling the temperature inside the refrigerator based on changes in the temperature inside the refrigerator.
When the resonance frequency of (2) or a frequency slightly higher than this resonance frequency or less, or in order to stop the operation of the compressor (5), the frequency from the controller (21) is the resonance frequency or this resonance frequency. When the frequency becomes slightly lower than the frequency, the magnet switch (23) is turned off by the off signal from the controller (21), and the compressor is forced.
Power to (5) is cut off. Therefore, when the compressor (5) is stopped, it does not enter the resonance frequency range controlled by the inverter (22), and as a result, resonance does not occur in the piping of the refrigeration system (2) and the refrigeration system ( It is possible to prevent cracks in the pipes and the like and cold air leakage due to the cracks when the (2) is used for a long time, and therefore, the maintenance and inspection work of the refrigeration system (2) can be simplified and the life can be extended.

In the above embodiment, the operation control device of the cooling device including one compressor (5) has been described, but in the cooling device including the plurality of compressors (5), each compressor is When the power is stopped, the power supply to the compressor is forcibly cut off before the frequency of the supplied power reaches the resonance frequency, whereby the same effect as that of the above embodiment can be obtained.

(G) Effect of the Invention Since the present invention is the operation control device for the refrigeration apparatus described in the above embodiments, the frequency of the electric power supplied from the inverter to the compressor is increased when the operation of the compressor is started. When the frequency reaches the resonance frequency, the power is continuously supplied to the compressor through the switch, and when the frequency is decreasing, the signal from the controller before the frequency decreases to the resonance frequency. Since the switch is turned off by the output and the power supply to the compressor is stopped, the refrigerating capacity of the refrigerating apparatus can be rapidly increased, and
It is possible to avoid the start and stop of the compressor when the frequency rises, the compressor is not operated in the resonance frequency range, the resonance of the refrigeration system can be avoided, and the failure of the compressor or switch and the damage to the piping etc. are prevented. Thus, the inspection work of the refrigeration system can be simplified and the service life can be extended.

[Brief description of drawings]

1 to 3 show an embodiment of the present invention, FIG. 1 is a schematic block circuit diagram of an operation control device, FIG. 2 is a schematic vertical sectional view of a prefabricated refrigerator, and FIG. 3 is an output frequency of a controller. FIG. 3 is a characteristic diagram of the voltage supplied to the compressor and the compressor. (2) …… Refrigerator, (5) …… Compressor, (6) …… Condenser, (8)
…… Evaporator, (21) …… Controller, (22) …… Inverter, (23) …… Magnet switch, (24) …… Temperature sensor.

Claims (1)

[Claims] 1. A refrigeration system in which a compressor, a condenser, an evaporator and the like are connected by piping, an inverter for controlling the frequency of AC power supplied to the compressor, and a refrigerator temperature sensing. In an operation control device for a refrigeration system, which includes a controller that inputs a signal from a temperature sensor and outputs a frequency signal to the inverter, a switch that shuts off power supply to the compressor is provided, and the switch is the frequency signal. Gradually increases, the power continues to be turned on when the frequency of the power supplied from the inverter to the compressor reaches the resonance frequency of the refrigeration system, and the frequency gradually decreases, and the resonance frequency and the resonance An operation control device for a refrigerating device, which is turned off based on a signal from the controller when the frequency is slightly higher than the frequency.