JP2006329574A - Operation control system for refrigerating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To further positively ensure the operation safety of an inverter refrigerating device by discriminating a failure causing the transition of low-pressure side pressure to the higher side from inevitable higher low-pressure side pressure caused by other operation or the like. <P>SOLUTION: In this operation control system for a refrigerating device, a power line of a compressor of a refrigerator has a first line connected to a power source through an inverter 1, and a second line connected to the power source without passing through the inverter 1, and when an operation signal to the inverter is outputted from a control part of a control mechanism 2, if the low-pressure side pressure detected by a pressure sensor 8 is not less than low-pressure side target pressure set by a pressure setting part within a preset time and not lower than abnormality determining pressure computed and set by the pressure setting part, an operating action switching signal output part 9 outputs a signal for switching the first line to the second line to switch the operation of the refrigerating device. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The invention of this application relates to an operation control system for a refrigeration apparatus. In more detail, the invention of this application more reliably ensures the safety of operation of a refrigeration apparatus in which an inverter is incorporated in a power line of a compressor incorporated in a refrigeration cycle in which a cooling unit and a refrigerator are connected by refrigerant piping. The present invention relates to a new refrigeration system operation control system that can be secured.

  Conventionally, an inverter refrigerator is known in which an inverter is arranged on a power line of a compressor of a refrigeration cycle so as to perform an efficient operation. In this type of inverter refrigerator, there are many cases where the low pressure side pressure of the refrigerant pipe is set to a high value to save energy and manage the freshness of food. In such a case, the following safety switches and methods have been conventionally used in order to ensure driving safety.

  Errors such as power supply voltage too high, too low, and too much operating current are error operations that the inverter itself has, and a signal indicating these error operations is output. I was doing. In addition, in the type of refrigerator in which a plurality of compressors are mounted, for example, a high pressure switch, an overcurrent protection switch, a hydraulic protection switch, a motor winding overheat prevention switch, etc. are provided for each compressor. Since an alarm signal is output when an error occurs, the control mechanism takes in these signals to take some action to ensure driving safety.

  However, in the following cases, there is a case in which failure is caused because the control mechanism cannot determine abnormality.

  In other words, in order to prevent the inverter from becoming overcurrent due to the pressure of the refrigeration cycle being too high, when the frequency is automatically lowered to operate (stall prevention operation), the refrigeration function is not sufficient, resulting in poor cooling. May occur, the control mechanism and the inverter control characteristics may not match, and the machine may be stopped, or the control signal may not be output correctly due to wiring or soldering problems.

  In addition, the setting of various devices becomes complicated, and a setting performed according to a certain operation state may cause a trouble in another operation state.

  Furthermore, it is necessary to perform a backup by some method against a logical error that is not an abnormality of the inverter itself or a hardware operation error of the refrigerator.

As a clue to solve the above problems, it is conceivable to use the technique previously proposed in Patent Document 1 by the inventor of this application. Although this method is intended for a normal refrigerator that is not an inverter refrigerator, it monitors the low-pressure side pressure of the refrigeration cycle and determines an abnormality of the apparatus. In this method, the abnormality is immediately determined when the low-pressure side pressure is high.
Japanese Utility Model Publication No. 7-16226 (utility model registration No. 2604501)

  However, many refrigeration apparatuses have a startup delay function in order to suppress frequent start / stop of the compressor. For this reason, the low-pressure side pressure increases within the startup delay time in the normal operation of the apparatus, but if the above method is used, it is determined to be abnormal. In addition, some models have a function of performing an oil return operation, but in this case, the compressor is forcibly stopped regardless of the value of the low-pressure side pressure. Thus, there are cases where it cannot be assumed that the operation is abnormal just by saying that the low-pressure side pressure is high. For these reasons, in many refrigeration systems, in order to reliably detect that some abnormality has occurred, it cannot be performed as the low-pressure side pressure becomes high, and it has been necessary to further devise. .

  The invention of this application has been made in view of the circumstances as described above, and a failure in which the low-pressure side pressure changes to a high level is inevitably caused by another operation or the like. Another object is to provide an operation control system for a refrigeration apparatus that can ensure the safety of operation of the inverter refrigeration apparatus more reliably.

In order to solve the above problems, the invention of this application is, firstly, in an operation control system for a refrigeration apparatus having a refrigeration cycle in which a cooling unit and a refrigerator are connected by a refrigerant pipe.
The compressor power line of the refrigerator has a first path connected to the power source via the inverter, and a second path directly connected to the power source not via the inverter, and the low pressure side pressure of the refrigerant pipe A control mechanism including a pressure sensor that detects the pressure, a control unit that controls the operation of the inverter, and a pressure setting unit that sets a low-pressure side target pressure and calculates and sets an abnormality determination pressure equal to or higher than the low-pressure side target pressure, The control mechanism further includes a low pressure side target pressure set by the pressure setting unit within a preset time when the low pressure side pressure detected by the pressure sensor is output when an operation signal is output from the control unit to the inverter. In order to reliably detect an abnormality when the pressure is not lower than the abnormality determination pressure calculated and set by the pressure setting unit, a new idea is to set a time limit for the time during which the high low pressure continues. Along towards and provides operational control system of a refrigeration apparatus comprising: a running operation switching signal output unit for outputting a signal for switching from the first path to the second path.

  Second, in the first invention, the plurality of compressors are connected by the same refrigerant pipe, and the power lines of the second and subsequent compressors are directly connected to the power source without passing through the inverter. Provides an operation control system for a refrigeration apparatus characterized by controlling the operation of the second and subsequent compressors.

  According to the invention of this application, a failure in which the low-pressure side pressure changes to a higher level is distinguished from a higher low-pressure side pressure that inevitably arises due to other operations or the like. It becomes possible to ensure safety more reliably.

  In addition, according to the invention of this application, the abnormality can be determined much earlier than the method of detecting the abnormality on the cooling unit side and determining the abnormality, and the low pressure side pressure is used as a result of the set time being high. There is an advantage that it is possible to include and manage types of abnormalities that cannot be detected by devices such as individual current alarm devices and pressure switches.

  The invention of this application has the features as described above, and an embodiment thereof will be described below.

  An electrical connection of an embodiment in which the operation system of the invention of the present application is applied to a refrigeration cycle of a refrigeration apparatus is schematically shown in FIG. 1, and a refrigerant pipe connection is schematically shown in FIG.

  First, the electrical connection will be described. The inverter (1) is attached to the power line (L1) of the first compressor (3) of the refrigerator in which several compressors are installed in the same refrigerant piping system. A No. 1 compressor frequency variable operation contactor (5) is provided between the output side of (1) and the No. 1 compressor (3). That is, a power line (L1) branched from a power line (L) of a commercial power source (not shown) is connected to the No. 1 compressor (3) via the inverter (1). Further, a contactor (6) for No. 1 compressor commercial operation is provided between the inverter (1) and the power line (L1 ') that branches from the power line (L) and does not pass through the inverter (1), The No. 1 compressor (3) can be directly connected. The power line (L1) including the contactor (5) and the power line (L1 ') including the contactor (6) are arranged in parallel. Further, the power line (L2) branched from the power line (L) includes a No. 2 compressor commercial operation contactor (7) so that commercial power can be directly supplied to the No. 2 compressor (4). Subsequent compressors (not shown) can also supply commercial power directly with contactors. An operation contact from the control mechanism (2) is provided in the excitation coil circuit of all contactors.

  The control mechanism (2) is connected to a signal line of a pressure sensor (8) connected to the refrigerant pipe on the low pressure side, so that the value of the low pressure side pressure can be acquired. Although not shown, the control mechanism (2) is provided with an inverter control unit for controlling the operation of the inverter (1), a setting mode dip switch, a numerical value setting switch, and the like. An operation signal is supplied from the inverter controller to the inverter (1), and the low-pressure side target pressure can be set by operating these switches. The control mechanism (2) is set with an abnormality determination differential pressure that determines how much the value of the low-pressure side pressure detected by the pressure sensor (8) is higher than the low-pressure side target pressure to indicate abnormal operation, The anisotropy determination pressure is obtained by adding the abnormality determination differential pressure to the low-pressure side target pressure. This abnormality determination differential pressure can be set using, for example, a value obtained by calculation in consideration of various conditions. In addition, the control mechanism (2) has a timer (10) as an abnormality determination time timer that measures the time during which the low pressure side pressure is higher than the low pressure target pressure by the abnormality determination differential pressure after the operation command is issued. Is provided. Further, the control mechanism (2) is provided with a contact point (9) that is switched when an abnormal operation occurs as an operation operation switching signal output unit.

  Next, the refrigerant pipe connection will be described. The cooler 1 (11), cooler 2 (12), and cooler 3 (13) on the cooling unit side (not shown) are arranged in parallel, and the first compressor (3) and It is connected to the No. 2 compressor (4). The discharge pipes of the No. 1 compressor (3) and No. 2 compressor (4) are connected to the condenser (14), the outlet of the condenser (14) is connected to the liquid receiver (15), and the liquid receiver ( The outlet of 15) is connected to the cooler 1 (11), the cooler 2 (12), and the cooler 3 (13) to form a refrigeration cycle. In addition, a cooling unit is illustrated as what contains the refrigerator and freezing showcase provided with the cooler 1 (11), the cooler 2 (12), and the cooler 3 (13), for example. A pressure sensor (8) is disposed on the low pressure side of the refrigerant pipe as shown in FIG.

  Next, the operation of this embodiment will be described.

  Here, the operation will be described by taking as an example a compressor parallel-installed inverter refrigeration apparatus that operates using the CFC 22 as a refrigerant.

  The set values in the control mechanism (2) are as follows: the low pressure target pressure is 0.26 MP, the abnormality determination differential pressure is 0.08 MP, and the abnormality determination time is 15 minutes.

  The output of the operation signal from the inverter control unit of the control mechanism (2) is sent to the inverter (1), the contactor (5) is closed, the contactor (6) is opened, and the power of the commercial power source is the power line (L), The first compressor (3) is operated by being supplied to the first compressor (3) through the route of the power line (L1), the inverter (1), and the contactor (5). If normal, the low pressure side pressure rises and exceeds the low pressure side target pressure, the No. 1 compressor (3) starts operation with variable frequency and accelerates to the set maximum frequency. When the cooling load is large and the low pressure side pressure does not drop to the low pressure side target pressure only by the operation of the No. 1 compressor (3), an operation signal is output from the control mechanism (2) to the No. 2 compressor (7), The contactor (7) is closed, and the No. 2 compressor (4) starts operation with commercial power. If a refrigerator having an appropriate capacity is selected in this way, the compressor is additionally started up until the low-pressure side pressure drops to the low-pressure side target pressure. Enter equilibrium.

  Here, for example, it is assumed that the frequency setting voltage wire from the control mechanism (2) to the inverter (1) is loose, and the output frequency is not correctly output to the inverter (1). In this case, even if an operation signal is output to the inverter (1), the frequency setting voltage for operating at any frequency is not transmitted, so the frequency of the inverter (1) does not increase. Then, since the No. 1 compressor (3) does not operate as prescribed, the low-pressure side pressure does not drop as planned, and the abnormality determination pressure (0.26MP + 0.08MP = 0.34MP) set in the control mechanism (2). Cannot fall below. When the operation in that state continues for 15 minutes, which is the abnormality determination time, the control mechanism (2) determines that there is some abnormality, and by switching the contact (9), the contactor (5) is opened and the contactor (6 ) Is closed, and the operation of the No. 1 compressor (3) is switched to the commercial power source without passing through the inverter (1). Further, the compressor after the No. 2 compressor (7) also switches the control to the commercial operation (mechanical contact pressure switch operation operation), and transmits an alarm signal for occurrence of an abnormality. Thus, the operation of the refrigeration apparatus can be continued and abnormality can be confirmed.

  Of course, the invention of this application is not limited to the above-described embodiments and examples, and various details are possible.

  For example, in the above embodiment, a plurality of compressors are mounted, but one may be used.

It is a figure which shows typically the electrical connection of one Embodiment of invention of this application. It is a figure showing typically refrigerant piping of one embodiment of the invention of this application.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inverter 2 Control mechanism 3 No. 1 compressor 4 No. 2 compressor 5 No. 1 compressor frequency variable operation contactor 6 No. 1 compressor commercial operation contactor 7 No. 2 compressor commercial operation contactor 8 Pressure sensor 9 Contact (operation) Operation switching signal output unit)
10 Timer (Abnormality judgment time counter)
11 Cooler 1
12 Cooler 2
13 Cooler 3
14 Condenser 15 Receiver

Claims (2)

In an operation control system of a refrigeration apparatus having a refrigeration cycle in which a cooling unit and a refrigerator are connected by a refrigerant pipe,
The power line of the compressor of the refrigerator has a first path connected to the power source via the inverter, and a second path connected directly to the power source without going through the inverter,
A pressure sensor that detects the low-pressure side pressure of the refrigerant piping, a control unit that controls the operation of the inverter, and a pressure setting unit that sets the low-pressure side target pressure and calculates and sets an abnormality determination pressure equal to or higher than the low-pressure side target pressure Having a control mechanism,
The control mechanism further includes a low pressure side target pressure set by the pressure setting unit within a preset time when the low pressure side pressure detected by the pressure sensor is output when an operation signal is output from the control unit to the inverter. A refrigeration apparatus comprising a driving operation switching signal output unit that outputs a signal for switching from the first path to the second path when the pressure is not lower than the abnormality determination pressure calculated and set by the pressure setting unit. Operation control system.   A plurality of compressors are connected by the same refrigerant pipe, the power lines of the second and subsequent compressors are directly connected to the power source without going through the inverter, and the control mechanism also controls the operation of the second and subsequent compressors. The operation control system for a refrigeration apparatus according to claim 1.

Images