JP2009008305A - Valve control method and valve control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a valve control method capable of stably controlling a temperature and elongating the service life of a valve. <P>SOLUTION: In this control method of an electric valve by determining the deviation between a detected degree of superheat Tsh and a set degree of superheat (target temperature) Ts, and controlling a valve opening of an expansion valve (electric valve) 4 on the basis of the determined deviation, the control of valve opening of the expansion valve 4 is stopped when the degree of superheat Tsh is within a first temperature range Tr1 including the target temperature Ts, and the stop of control of the valve opening of the expansion valve 4 is kept for a time when the degree of superheat Tsh is within a second temperature range Tr2 including the first temperature range Tr1 and wider than the first temperature range Tr1. When the degree of superheat Tsh is outside of the temperature range Tr2, the stop of control of the valve opening of the expansion valve 4 is released to restart the control of valve opening, so that the degree of superheat Tsh is quickly restored to the neighborhood of the target temperature Ts. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a valve control method and a valve control device, and more particularly to a method for controlling the valve opening of an electric valve or the like that adjusts the flow rate of a refrigerant.

  The electric valve has various uses such as being used as an expansion valve for controlling the flow rate of the refrigerant in the refrigeration cycle. When the motor-operated valve is used as an expansion valve for a refrigeration cycle, the valve opening of the motor-operated valve is generally controlled based on the deviation between the actual superheat (detected temperature) and the set superheat (target temperature). It is. However, since the degree of superheat maintains a slight temperature change and does not maintain a constant temperature even in a steady state, if the valve opening degree of the motorized valve is controlled based on the target temperature, the motorized valve It will continue to fine-tune the valve opening.

Therefore, as shown in FIG. 10, a predetermined temperature range (dead zone) Tr including the target temperature Ts is provided, and if the detected temperature does not coincide with the target temperature Ts, the valve opening degree is controlled if it falls within the dead zone Tr. Is stopped (see, for example, Patent Document 1). That is, in the initial stage of temperature control, the valve opening degree of the motor-operated valve is actively changed to rapidly bring the detected temperature close to the target temperature Ts. After that, if the detected temperature falls within the dead zone Tr, Without changing the valve opening, the valve opening at that time is maintained.
Japanese Patent Publication No. 3-22555

  However, in the above valve opening control method, control of the valve opening is stopped based on the dead zone Tr, so that the degree of superheat becomes a steady state at the central portion of the dead zone Tr (near the target temperature Ts). However, the temperature may be close to the upper limit value or lower limit value of the dead zone Tr. In such a state, if the temperature change with a slight degree of superheat is repeated, the detected temperature easily enters and exits the dead zone Tr, and the execution and stop of the valve opening degree control are frequently switched as shown in FIG. Will be. For this reason, a problem arises that the motorized valve becomes a hunting operation, the temperature vibrates, and stable temperature control becomes difficult.

  In addition, when the detected temperature is stable near the boundary of the dead zone Tr while being in a steady state, the valve opening degree control is frequently switched between execution and stop in response to a minute change in the detected temperature. The motorized valve that does not need to be moved will be moved more than necessary. For this reason, there also exists a problem that deterioration of a motor-driven valve is accelerated | stimulated and the lifetime of a motor-operated valve becomes short.

  Therefore, the present invention has been made in view of the above-described problems in the prior art, and is capable of performing stable temperature control and capable of extending the life of the valve. The purpose is to provide.

  In order to achieve the above object, the present invention obtains a deviation between a detected temperature and a target temperature, and in the valve control method for controlling the valve opening of the valve based on the obtained deviation, the detected temperature is: When it is within the first temperature range including the target temperature, the control of the valve opening of the valve is stopped, and then the detected temperature includes the first temperature range, The control stop of the valve opening degree of the valve is maintained while the temperature is within the second temperature range wider than the temperature range.

  And according to the present invention, even if the detected temperature repeatedly enters and exits the first temperature range, if the temperature is within the second temperature range, the control stop of the valve opening is maintained. It is possible to prevent frequent switching between execution and stop of the valve opening degree control. For this reason, hunting of the valve can be prevented and stable temperature control can be performed. In addition, according to the present invention, since the control stop of the valve opening is maintained, it is possible to suppress the unnecessary execution of the valve opening control in the steady state and the switching of the stop. The number of operations can be reduced. Thereby, deterioration of a valve can be suppressed and it becomes possible to prolong the lifetime of a valve.

  Further, the present invention provides a valve control device that obtains a deviation between a detected temperature and a target temperature, and controls a valve opening degree of the valve based on the obtained deviation, wherein the first temperature range includes the target temperature. Storage means for storing a second temperature range that includes the first temperature range and is wider than the first temperature range, and the detected temperature is within the first temperature range. The control of the valve opening of the valve is stopped, and thereafter, the control stop of the valve opening of the valve is maintained while the detected temperature is within the second temperature range. And a valve control means. According to the present invention, similarly to the above-described invention, it is possible to prevent hunting of the valve and perform stable temperature control, and to suppress the deterioration of the valve and prolong the life of the valve. Is possible.

  In the valve control device, the valve control means can be configured to cancel the control stop of the valve opening degree of the valve when the detected temperature is out of the second temperature range. . According to the above configuration, when the detected temperature goes out of the second temperature range, the control of the valve opening can be resumed immediately. Therefore, a relatively large temperature due to a disturbance that is not in a steady state or the like. It is possible to respond flexibly to changes and quickly converge the detected temperature to the vicinity of the target temperature.

  The valve control device may include setting change means for changing the first and second temperature ranges stored in the storage means. According to this configuration, the first and second temperature ranges can be freely set in accordance with the intended use of the valve control device and the required temperature control accuracy. Thereby, the versatility as a product and the freedom degree for a user can be raised, and it becomes possible to improve the convenience.

  In the valve control device, the valve may be an expansion valve in a refrigeration cycle system, and the detected temperature may be a superheat degree. According to this configuration, in the refrigeration cycle system, stable superheat control can be performed, and the life of the expansion valve can be extended.

  In the valve control device, the valve may be a flow control valve in a hot gas bypass circuit of a refrigeration cycle system, and the detected temperature may be an evaporator temperature or a temperature corresponding thereto. Here, the temperature corresponding to the temperature of the evaporator means the temperature of the control target to be controlled using the evaporator of the refrigeration cycle system such as the outlet temperature of the evaporator, the evaporation temperature of the refrigerant, the inlet temperature of the evaporator, etc. Means. According to the above configuration, in the refrigeration cycle system using the hot gas bypass circuit, it is possible to perform stable temperature control of the temperature of the evaporator or the temperature corresponding thereto, and extend the life of the flow control valve. It becomes possible to become.

  As described above, according to the present invention, stable temperature control can be performed and the life of the valve can be extended.

  Next, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, a case where the valve control device according to the present invention is used as a device for controlling an electric valve arranged in a refrigeration cycle system will be described as an example.

  FIG. 1 shows a refrigeration cycle system provided with a valve control device according to the present invention. This system 1 includes a compressor 2, a condenser 3, a condenser fan 3a, an expansion valve (motor valve) 4, An evaporator 5, an evaporator fan 5 a, an inlet temperature sensor 6, an outlet temperature sensor 7, and an electric valve control device 8 are provided.

  The compressor 2, the condenser 3, the expansion valve 4, and the evaporator 5 are connected by a pipe 9, and the refrigerant circulates between them. Here, the flow rate of the refrigerant flowing through the pipe 9 is controlled by adjusting the valve opening degree of the expansion valve 4.

  The compressor 2 compresses the refrigerant in a low-pressure gas state supplied from the evaporator 5, converts the refrigerant into a high-pressure gas, and supplies it to the condenser 3 through the pipe 9.

  The condenser 3 condenses the high-pressure gaseous refrigerant supplied from the compressor 2, converts it into a high-pressure liquid refrigerant, takes away the heat of condensation, and releases the taken-out heat to the outside by the ventilation of the condenser fan 3a. .

  The expansion valve 4 changes the high-pressure liquid refrigerant supplied from the condenser 3 to a low-pressure state. This expansion valve 4 incorporates a pulse motor 4a (see FIG. 3) that is driven in accordance with a drive signal from the electric valve control device 8, and the pulse motor 4a rotates at a rotation angle corresponding to the number of pulses of the drive signal. The valve opening degree of the expansion valve 4 is adjusted.

  The evaporator 5 is provided to evaporate (vaporize) the refrigerant in a low-pressure liquid state, and the refrigerant takes heat of vaporization from the surroundings by being evaporated and is heated. At this time, the air around the evaporator 5 is cooled by the deprived heat, and the cooled air is released by the ventilation of the evaporator fan 5a, thereby adjusting the temperature of the temperature control target (for example, the room temperature). Done.

  The inlet temperature sensor 6 and the outlet temperature sensor 7 are, for example, three-wire platinum resistance thermometers, and are temperature sensors that can measure temperature with high accuracy. The inlet temperature sensor 6 detects the temperature Tin of the refrigerant at the inlet of the evaporator 5, that is, the refrigerant in the liquid state, and the outlet temperature sensor 7 detects the refrigerant at the outlet of the evaporator 5, that is, the refrigerant in the gaseous state. The temperature Tout is detected.

  The motor-operated valve control device 8 is for controlling the valve opening degree of the expansion valve 4, and the superheat degree Tsh of the refrigerant in the evaporator 5 (the detected temperature Tout of the outlet temperature sensor 7−the detected temperature of the inlet temperature sensor 6). Based on (Tin), the valve opening of the expansion valve 4 is obtained by PID control, and a drive signal corresponding to the obtained valve opening is output to the pulse motor 4a of the expansion valve 4.

  The motor-operated valve control device 8 is set with first and second temperature ranges Tr1 and Tr2 (see FIG. 2). Although details will be described later, the motor-operated valve control device 8 includes the first and second temperature ranges. Execution and stop of the control of the valve opening degree of the expansion valve 4 are switched with reference to the temperature ranges Tr1 and Tr2. Each of the first and second temperature ranges Tr1 and Tr2 is a temperature range centered on a superheat degree target value (hereinafter referred to as “target temperature”) Ts, and of these, the first temperature range Tr1 corresponds to the dead zone Tr in FIG. On the other hand, the second temperature range Tr2 is set so as to be wider than the first temperature range Tr1 and include the first temperature range Tr1 inside thereof.

  As shown in FIG. 3, the motor-operated valve control device 8 includes a microprocessor 11, an inlet temperature detection circuit 12, an outlet temperature detection circuit 13, a motorized valve drive circuit 14, an input circuit 15, and a display circuit 16. A display driver circuit 17 and a memory circuit (EEPROM) 18.

  The inlet temperature detection circuit 12 is a resistance-voltage conversion circuit that converts the resistance value of the inlet temperature sensor 6 into a DC voltage signal and outputs the DC voltage signal to the microprocessor 11. The inlet temperature detection circuit 12 includes a bridge circuit 12a and an amplifier circuit 12b that amplifies the voltage between the intermediate terminals of the bridge circuit 12a in order to accurately detect the refrigerant temperature Tin at the inlet of the evaporator 5. .

  The outlet temperature detection circuit 13 is a resistance-voltage conversion circuit that converts the resistance value of the outlet temperature sensor 7 into a DC voltage signal and outputs the DC voltage signal to the microprocessor 11. The outlet temperature detection circuit 13 is also composed of a bridge circuit 13a and an amplifier circuit 13b in order to accurately detect the refrigerant temperature Tout at the outlet of the evaporator 5.

  The input circuit 15 has a target temperature Ts, an upper limit opening degree and a lower limit opening degree of the expansion valve 4 (for example, when an electric valve is used with 100 pulses to 400 pulses, the upper limit opening degree is 400 pulses and the lower limit opening degree is 100 pulses. ), P (proportional), I (integral), D (differential) constants, first and second temperature ranges Tr1, Tr2, and the like when performing PID control. These various input values can be set as set values, and the set set values can be changed by using the input circuit 15. The method for setting the input value and the method for changing the set value will be described in detail later.

  The input circuit 15 includes four tact switches 15a to 15d (up switch 15a, down switch 15b, set switch 15c, and enter switch 15d), and outputs ON / OFF states of the tact switches 15a to 15d to the microprocessor 11. .

  The display circuit 16 includes a temperature display element 16a, a valve opening display element 16b, and a plurality of LEDs 16c. The temperature display element 16a switches and displays the refrigerant temperature Tin at the inlet of the evaporator 5, the refrigerant temperature Tout at the outlet, and the superheat degree Tsh (= Tout−Tin), and in the setting mode, the first temperature range Tr1 and The set value of the second temperature range Tr2 is displayed. Further, the valve opening display element 16b displays the current opening of the expansion valve 4 by the number of pulses from the fully closed state.

  The plurality of LEDs 16c are lit according to the display items of the temperature display element 16a and the valve opening degree display element 16b, and are composed of six LEDs from “superheat degree” to “alarm”. The “superheat”, “inlet”, and “exit” LEDs are for indicating display items of the temperature display element 16a, and light up corresponding to the temperature displayed on the temperature display element 16a. The “setting” LED is lit when the motor-operated valve control device 8 is in the setting mode, and the “operation” LED is lit when the motor-operated valve control device 8 is in operation. The “alarm” LED blinks when the output data of the inlet temperature sensor 6 and the outlet temperature sensor 7 is abnormal.

  The display driver circuit 17 amplifies the signal from the microprocessor 11 and outputs the amplified signal to the display circuit 16. The storage circuit 18 stores the set value and the like for backup.

  The electric valve drive circuit 14 is provided to amplify a drive control signal from the microprocessor 11 and output a drive pulse to a pulse motor (stepping motor) 4a built in the expansion valve 4, and a driver IC (Integrated Circuit). ) (Drive signal amplifier circuit) 14a and the like.

  The microprocessor 11 includes an A / D converter 11a, a CPU (Central Processing Unit) 11b, a ROM 11c, a RAM 11d, a timer 11e, an I / O (11f), and the like. The A / D converter 11a converts the analog temperature signal output from the inlet temperature detection circuit 12 and the outlet temperature detection circuit 13 into a digital signal, and the CPU 11b interprets and executes the program stored in the ROM 11c. . The ROM 11c is a nonvolatile memory that stores an operation program for executing control of valve opening by a PID control operation, which will be described later, an operation program for switching control between execution and stop of valve opening, a display control program, and the like. It is memory. The RAM 11d functions as a work memory for the CPU 11b. The timer 11e is provided to perform interrupt processing and the like, and the I / O (11f) is provided to exchange data between the CPU 11b and other devices.

  Next, regarding the control operation performed by the motor-operated valve control device 8 of the above-described refrigeration cycle system 1, the operation of the microprocessor 11 constituting the main part of the motor-operated valve control device 8 will be mainly described with reference to FIGS. explain. During the control operation, the microprocessor 11 uses the timer 11e to perform the interrupt process shown in FIG. 4 at a predetermined cycle, for example, at intervals of 1 second.

  When the interruption process is started, as shown in FIG. 4, the CPU 11b first takes in the refrigerant temperature Tin at the inlet of the evaporator 5 and the refrigerant temperature Tout at the outlet which have been A / D converted (steps S1 and S2), A current superheat degree Tsh = Tout−Tin is calculated (step S3). Next, a deviation e (t) = Ts−Tsh between the target temperature Ts and the calculated current superheat degree Tsh is calculated (step S4), and the absolute value of the calculated deviation e (t) | e (t) | Is calculated (step S5).

  Next, the calculated absolute value | e (t) | of the deviation is compared with the first temperature range Tr1 (step S6). The value of the first temperature range Tr1 used at this time is not the overall size (range width) of the first temperature range Tr1, but the upper limit value and the lower limit value of the first temperature range Tr1 from the target temperature Ts. The size (range width). Therefore, for example, as shown in FIG. 2, if the first temperature range Tr1 is set to ± 0.5 ° C. with respect to the target temperature Ts, the value of the first temperature range Tr1 used in step S6 is The first temperature range Tr1 is not 1.0 ° C. which is the entire size, but 0.5 ° C. which is the size from the target temperature Ts to the end of the first temperature range Tr1.

  Hereinafter, in order to distinguish between the size of the entire first temperature range Tr1 and the size from the target temperature Ts to the end of the first temperature range Tr1, the latter is referred to as “first temperature range Tr1 ′”. The same applies to the second temperature range Tr2.

  Returning to FIG. 4, when the absolute value | e (t) | of the deviation is equal to or smaller than the first temperature range Tr1 ′ as a result of the comparison in step S6, the CPU 11b sets the value of the stop flag SF to “1”. It is set and stored in the RAM 11d, and the stop flag SF is set (step S7). At this time, if the control of the valve opening is executed at the start of the interrupt process, the control of the valve opening is stopped, the interrupt process is terminated, and the control of the valve opening is not executed. If this happens, the interrupt process is terminated while maintaining that state.

  On the other hand, when the absolute value of deviation | e (t) | is larger than the first temperature range Tr1 ′, the absolute value of deviation | e (t) | is compared with the second temperature range Tr2 ′. Then, it is determined whether or not the absolute value | e (t) | of the deviation is larger than the second temperature range Tr2 ′ (step S8). If the absolute value | e (t) | of the deviation is larger than the second temperature range Tr2 ′ as a result of the determination, the value of the stop flag SF stored in the RAM 11d is rewritten to “0” and the stop flag SF is changed. Clear (step S9).

Then, past a series of deviation e, a proportional band PB, integration time T _I, based on the derivative time T _D, in accordance with the following equation, PID manipulated variable of the current valve opening degree (proportional-integral-derivative) operation m (t) Is calculated (step S10), and the calculation result is set to the target opening (step S11). Here, K _P is a proportional gain.

  As a result, the target opening of the valve to be reached by the expansion valve 4 is set. After the microprocessor 11 stores the target opening in the RAM 11d, the opening of the expansion valve 4 becomes the target opening stored in the RAM 11d. Thus, a drive signal is supplied from the driver IC 14a of the electric valve drive circuit 14 to the pulse motor 4a.

  On the other hand, if the absolute value | e (t) | of the deviation is equal to or smaller than the second temperature range Tr2 ′ as a result of the determination in step S8, the value of the stop flag SF stored in the RAM 11d is “1”. It is determined whether or not there is (step S12). Here, it is determined whether or not the value of the stop flag SF is “1” because the slight temperature change has occurred in the superheat degree Tsh, and the absolute value of deviation | e (t) | Is greater than the first temperature range Tr1 ′ and less than or equal to the second temperature range Tr2 ′, or the absolute value of deviation | e (t) | is equal to the second temperature in the process of the PID control. This is to determine whether the range is equal to or less than Tr2 ′.

  As a result of the determination, when the value of the stop flag SF is “1”, it indicates that the control of the valve opening degree was stopped when the previous interrupt process was executed. Due to the change, it is determined that the degree of superheat Tsh is outside the first temperature range Tr1, and in this case, the control of the valve opening degree is maintained and the interruption process is terminated.

  On the other hand, when the value of the stop flag SF is not “1” (“0”), it indicates that the control of the valve opening degree is being executed at the time of the previous interruption processing. It is determined that the degree of superheat Tsh is approaching the target temperature Ts, and in this case, the PID calculation is executed to calculate the operation amount m (t) of the current valve opening, and the calculation The result is set to the target opening (steps S10 and S11).

  Next, an example of switching operation between execution and stop of the valve opening degree will be described with reference to FIGS. 1 and 3 focusing on FIG.

When the operation of the refrigeration cycle system 1 is started at the timing t ₀ , the motor-operated valve control device 8 starts control of the valve opening degree of the expansion valve 4, and based on the deviation between the superheat degree Tsh and the target temperature Ts, An operation amount m (t) of the valve opening degree of the expansion valve 4 is calculated by calculation. Then, the number of pulses of the drive signal is determined according to the calculated operation amount m (t), and the drive signal is output to the pulse motor 4a of the expansion valve 4 to control the valve opening degree of the expansion valve 4.

Thereafter, until the superheat degree Tsh reaches the upper limit value of the first temperature range Tr1, the valve opening degree is controlled, and the PID calculation is repeated in units of one second (interrupt processing execution cycle). Is rapidly brought close to the target temperature Ts. Then, at the timing t _1, when the degree of superheat Tsh reaches the upper limit of the first temperature range Tr1, the electric valve controller 8 stops the control of the valve opening to maintain the valve opening degree at that time .

However, since the above period is a transition period in which the degree of superheat Tsh is approaching the target temperature Ts, the degree of superheat Tsh has a steep slope even if the motor-operated valve control device 8 stops controlling the valve opening degree. Keep falling while keeping. Then, at timing t _2, when the degree of superheat Tsh is less than the lower limit of the second temperature range Tr2, the electric valve control device 8, and release of the control stop of the valve opening, the expansion valve to perform the PID calculation 4 is controlled. As a result, the superheat degree Tsh rises toward the target temperature Ts after reaching a minimum value.

At timing t _3, the degree of superheat Tsh reaches the lower limit of the first temperature range Tr1, the electric valve controller 8, again, to stop the control of the valve opening to maintain the valve opening degree at that time . Thereafter, the degree of superheat Tsh becomes a steady state, and only a slight temperature change is repeated.

Thus, when the degree of superheat Tsh becomes a steady state, the motor-operated valve control device 8 maintains the control of the valve opening degree until the degree of superheat Tsh is outside the second temperature range Tr2. For this reason, even if the degree of superheat Tsh exceeds the upper limit value of the first temperature range Tr1 (timing t ₄ , t ₅ , t ₆ ) or falls below the lower limit value of the first temperature range Tr1 (timing t ₇ , t ₈ ) When the temperature is within the second temperature range Tr2, control of the valve opening is not executed, and the valve opening of the expansion valve 4 is maintained at the opening when the control of the valve opening is stopped. The

Thereafter, at timing t ₉ , for example, when a disturbance such as opening / closing of a room door occurs, and the superheat degree Tsh rapidly rises due to the influence, the motor-operated valve control device becomes higher than the upper limit value of the second temperature range Tr 2. 8 releases the control stop of the valve opening and executes the PID calculation to control the valve opening of the expansion valve 4. As a result, the superheat degree Tsh rapidly decreases toward the target temperature Ts after reaching the maximum value.

Then, at a timing t _10, when the degree of superheat Tsh is less than the upper limit of the first temperature range Tr1, the electric valve controller 8, again, to stop the control of the valve opening, then the degree of superheat Tsh second During the temperature range Tr2, the control stop of the valve opening degree is maintained.

  In the case of superheat control using a motor-operated valve, it is always overheated due to a change in the state of the refrigerant (for example, change from liquid to gas) even during steady operation, as compared with a capillary-type throttle mechanism. There is a slight variation in the degree Tsh. Further, when an electric valve is used for the expansion valve 4, the degree of superheat Tsh itself is not a direct target for temperature control of the refrigeration cycle system 1. For these reasons, the required control accuracy of the degree of superheat Ts is about ± 1.0 ° C. Therefore, the first and second temperature ranges Tr1 and Tr2 are ± 0 with respect to the target temperature Ts, respectively. It is preferable that the temperature is about 5 ° C. and about ± 1.0 ° C.

  As described above, in the present embodiment, after the degree of superheat Tsh falls within the first temperature range Tr1 and the control of the valve opening degree of the expansion valve 4 is stopped, the degree of superheat Tsh becomes the second temperature range Tr2. In order to maintain the control stop of the valve opening while it is within, even if the superheat degree Tsh repeatedly enters and exits in the vicinity of the upper limit value or the lower limit value of the first temperature range Tr1, It is possible to prevent frequent stoppages. Thereby, hunting of the expansion valve 4 can be prevented, and stable temperature control can be performed.

  Further, according to the above configuration, since the control stop of the valve opening degree is maintained, it is possible to suppress the unnecessary execution of the valve opening degree control in the steady state and the switching of the stop. The number of operations can be reduced. Thereby, deterioration of the expansion valve 4 can be suppressed, and the life of the expansion valve 4 can be extended.

  Further, in this embodiment, when the degree of superheat Tsh goes out of the second temperature range Tr2 from the second temperature range Tr2, the control stop of the valve opening is immediately released and the control of the valve opening is controlled. Therefore, it is possible to flexibly cope with a relatively large temperature change due to a disturbance that is not in a steady state, and to quickly converge the superheat degree Tsh to the vicinity of the target temperature Ts. In particular, in the present embodiment, while the degree of superheat Tsh is within the second temperature range Tr2, the control stop of the valve opening degree is maintained, so the detection interval of the superheat degree Tsh (valve opening change interval). Even if is shortened, the valve opening of the expansion valve 4 is not changed frequently, and execution and stop of the control of the valve opening are not switched violently. Therefore, it is possible to detect a change in the superheat degree Tsh at a short detection interval, thereby quickly detecting the occurrence of a sudden temperature change, and quickly detecting the superheat degree Tsh at the first temperature when a disturbance or the like occurs. It is possible to converge within the range Tr1.

  Next, the overall flow of the input (change) operation of each set value using the input circuit 15 and the display circuit 16 of FIG. 3 will be described with reference to FIG. FIG. 6 is a schematic diagram showing the external appearance of the surface of the main body of the electric valve control device 8.

  For example, when the temperature is displayed on the temperature display element 16a and the current valve opening is displayed on the valve opening display element 16b, when the set switch 15c is pressed, the setting mode is entered, and the temperature display element 16a The normal temperature display mode is changed to the set value display mode, and the valve opening display element 16b is switched from the current valve opening display to the setting item display. The set value displayed on the temperature display element 16a can be increased / decreased by pressing the up switch 15a or the down switch 15b, and the displayed set value is updated by pressing the enter switch 15d. It is updated and stored as a set value.

  On the other hand, there are eight setting items as shown in Table 1, for example, and a set value number and a symbol are displayed on the valve opening degree display element 16b, for example, “1SH”. This setting item is sequentially switched to the next item by pressing the set switch 15c in the setting mode, and when the setting switch 8c is displayed when the setting item 8 ("8SP") is displayed. , Exits the setting mode and returns to the temperature display and valve opening display states.

  The input value of the first temperature range Tr1 is not the size of the entire first temperature range Tr1, but the size from the target temperature Ts to the end of the first temperature range Tr1 (Tr1 '). On the other hand, the input value of the second temperature range Tr2 is also set to the magnitude (Tr2 ') from the target temperature Ts to the end of the second temperature range Tr2. Moreover, as shown in Table 1, the maximum values that can be input in the first and second temperature ranges Tr1 and Tr2 are both 1.0 ° C. As described above, the first and second temperature ranges are the same. Tr1 and Tr2 are preferably set to about 0.5 ° C. and about 1.0 ° C., respectively.

  Next, a specific flow of the setting value changing operation will be described with reference to FIG.

  When the temperature is displayed on the temperature display element 16a (step S21), it is determined whether or not the set switch 15c is pressed in step S22. If the set switch 15c is pressed, the temperature display element 16a is determined in step S23. The setting value is displayed in the setting mode, and if it is not pressed, the process returns to the state of step S21.

  Next, in step S24, it is determined whether or not the up switch 15a has been pressed. If it has been pressed, it is determined in step S25 whether or not the display value of the temperature display element 16a is the maximum set value. judge. As a result of the determination, if the display value is not the maximum value of the set value, 1 is added to the display value in step S26, and the process returns to step S24. On the other hand, when the display value is the maximum value of the set value, the process directly returns to step S24.

  Returning to step S24, it is determined whether or not the up switch 15a has been pressed. If the up switch 15a has been pressed, the operations of steps S25 to S26 are repeated. If it is determined in step S24 that the up switch 15a has not been pressed, it is determined in step S27 whether or not the down switch 15b has been pressed. If so, the display value is displayed in step S28. Is the minimum value of the set value. If the display value is not the minimum value of the set value, 1 is decremented to the display value in step S29, and the process returns to step S24. On the other hand, when the display value is the minimum value of the set value, the process directly returns to step S24.

  If it is determined in step S27 that the down switch 15b has not been pressed, it is determined in step S30 whether or not the enter switch 15d has been pressed. The display value is updated as the set value, and the updated set value is stored in the storage circuit 18 of FIG. 3, and the process returns to step S24.

  If the enter switch 15d is not pressed in step S30, it is determined in step S32 whether or not the set switch 15c is pressed. If it is determined that the set switch 15c is not pressed, the process returns to step S24.

  If it is determined in step S32 that the set switch 15c has been pressed, it is determined in step S33 whether or not to end the setting. Specifically, when the set switch 15c is pressed while the “second temperature range Tr2” of the setting item 8 is displayed in step S32, it is determined in step S33 that the setting mode has ended, Return to step S21. On the other hand, if an item other than “second temperature range Tr2” in setting item 8 is selected in step S32, and the set switch 15c is pressed, the next set value is set to the temperature in step S34. The information is displayed on the display element 16a, the process returns to step S24, and the above operation is repeated.

  As described above, in the present embodiment, the user can input the set values of the first and second temperature ranges Tr1, Tr2, and the set first and second temperature ranges Tr1, Tr2 can be set. Since it can also be changed, the first and second temperature ranges Tr1 and Tr2 can be freely set according to the intended use of the refrigeration cycle system 1 and the required temperature control accuracy. Thereby, the versatility as a product and the freedom degree for a user can be raised, and it becomes possible to improve the convenience.

  Next, as a second embodiment of the present invention, the valve control device according to the present invention is applied to a flow control valve of a hot gas bypass circuit of a refrigeration cycle system used when performing precision air conditioning or the like. explain.

  As shown in FIG. 8, the refrigeration cycle system 30 includes a compressor 2, a condenser 3, a condenser fan 3a, an expansion valve 35, an evaporator 5, an evaporator fan 5a, a flow control valve ( In addition to the basic configuration shown in FIG. 1, a hot gas bypass pipe 33 that connects the outlet of the compressor 2 to the inlet of the evaporator 5 is provided. The hot gas cycle 34 is configured to return from the outlet side to the inlet side of the compressor 2 through the flow rate control valve 32 and the evaporator 5. Here, the expansion valve 35 is a mechanical expansion valve or a capillary.

  The compressor 2, the condenser 3, the expansion valve 35, and the evaporator 5 are connected by a pipe 9, and the compressor 2, the flow control valve 32, and the evaporator 5 are hot gas bypass pipes. 33 and the pipe 9 are connected, and the refrigerant circulates between them. That is, the refrigerant from the compressor 2 is divided into the pipe 9 and the hot gas bypass pipe 33, and the flow rate of the refrigerant flowing through the hot gas bypass pipe 33 is controlled by adjusting the valve opening degree of the flow control valve 32.

  The compressor 2, the condenser 3, and the condenser fan 3 a have the same functions as those shown in FIG. 1, and thus detailed description is omitted, but the compressor 2 is supplied from the evaporator 5. The refrigerant in a low-pressure gas state is compressed, converted into a high-pressure and high-temperature gas, supplied to the condenser 3, and also supplied to the evaporator 5 through the hot gas bypass pipe 33.

  As described above, the expansion valve 35 is not a motorized type like the expansion valve 4 of FIG. 1, and a mechanical valve or capillary is used and is not controlled by the motorized valve control device 8.

  The evaporator 5 is provided to evaporate (vaporize) the refrigerant in a low-pressure liquid state, and the refrigerant takes heat of vaporization from the surroundings by being evaporated and is heated. The surroundings are cooled by the deprived heat, and the cooled air is released by the ventilation of the evaporator fan 5a. The evaporator 5 is supplied with high-pressure and high-temperature gas from the compressor 2 via the flow rate control valve 32, and the evaporator 5 is heated by this high-pressure and high-temperature gas. Thus, precise control is performed by simultaneously performing cooling and heating and adjusting the heating amount for the cooling at that time by the flow rate control valve 32.

  The temperature sensor 31 is, for example, a three-wire platinum resistance thermometer, and detects the blowing temperature (hereinafter referred to as “blowing temperature”) Tb of the evaporator 5.

  Since the motor-operated valve control device 8 has the same configuration as that shown in FIG. 3, a detailed description thereof will be omitted. In FIG. In the present embodiment, based on the deviation between the blowout temperature Tb detected by the temperature sensor 31 and the target temperature Ts, the opening degree of the flow control valve 32 is obtained by PID calculation, and the pulse is obtained so that the obtained opening degree is obtained. A drive signal is supplied to the motor 4a. In addition, the first and second temperature ranges Tr1 and Tr2 are set in the motor-operated valve control device 8 as in the first embodiment, and the motor-operated valve control device 8 has the first and second temperature ranges Tr1. , Tr2 is controlled so as to switch between execution and stop of the valve opening degree of the flow rate control valve 32.

  The refrigeration cycle system 30 using the hot gas bypass circuit is often used for precise temperature adjustment, and the temperature controlled during operation is the temperature around the evaporator 5 and is subject to temperature adjustment. Since the temperature and the temperature directly controlled by the refrigeration cycle system 30 are the same, the required accuracy is increased. For this reason, it is preferable that the first and second temperature ranges Tr1 and Tr2 be narrower than in the case of superheat control by the electric valve, and specifically, ± 0.1 ° C. with respect to the target temperature Ts. About ± 0.2 ° C. is preferable.

  The basic configuration of the input circuit 15 and the display circuit 16 is the same as that shown in FIG. 3, but in the present embodiment, when the target temperature Ts is set, the superheat degree Tsh of the evaporator 5 is replaced. The blowing temperature Tb is set using the input circuit 15. The display circuit 16 also displays the blowout temperature Tb instead of the degree of superheat Tsh, and displays the valve opening degree of the flow control valve 32 instead of the valve opening degree of the expansion valve 4.

  Next, regarding the control operation performed by the motor-operated valve control device 8 of the refrigeration cycle system 30 described above, the operation of the microprocessor 11 constituting the main part of the motor-operated valve control device 8 with reference to FIGS. 3, 8 and 9. The explanation will be focused on. In FIG. 9, the same steps as those shown in FIG. 5 are denoted by the same step numbers, and detailed description thereof is omitted. Further, during the control operation, the microprocessor 11 uses the timer 11e and executes the interrupt process shown in FIG. 9 at intervals of 1 second, for example.

  When the interruption process is started, as shown in FIG. 9, the CPU 11b first takes in the blowout temperature Tb subjected to A / D conversion (step S41), and the deviation e (t) between the target temperature Ts and the current blowout temperature Tb. ) = Ts−Tb is calculated (step S42). Next, an absolute value | e (t) | of the calculated deviation e (t) is calculated (step S5), and whether the calculated absolute value | e (t) | of the deviation is within the first temperature range Tr1 ′. It is determined whether or not (step S6).

  If the absolute value | e (t) | of the deviation is within the first temperature range Tr1 ′ as a result of the determination, the value of the stop flag SF is set to “1” and the valve opening degree of the flow control valve 32 is set. Control is stopped (step S7). On the other hand, when the absolute value | e (t) | of the deviation is larger than the first temperature range Tr1, it is determined whether or not the absolute value | e (t) | of the deviation is larger than the second temperature range Tr2 ′. (Step S8).

  If the absolute value | e (t) | of the deviation is within the second temperature range Tr2 ′, it is determined whether or not the value of the stop flag SF is “1” (step S12), and the stop flag SF If the value of “1” is “1”, the control stop of the valve opening is maintained. On the other hand, if the value of the stop flag SF is not “1”, PID calculation processing and target opening setting processing are executed to control the valve opening of the flow control valve 32 (steps S10 and S11).

  If the absolute value | e (t) | of the deviation is larger than the second temperature range Tr2 ′ as a result of the determination in step S8, the value of the stop flag SF is set to “0” (step S9). PID calculation processing and target opening setting processing are executed to control the valve opening of the flow control valve 32 (steps S10 and S11).

  Due to the above interrupt processing, also in the present embodiment, when the blowing temperature Tb falls within the first temperature range Tr1, the control of the valve opening degree of the flow control valve 32 is stopped, and then the blowing temperature Tb. Is within the second temperature range Tr2, control stop of the valve opening is maintained. Therefore, even if the blowing temperature Tb repeatedly enters and exits in the vicinity of the upper limit value or the lower limit value of the first temperature range Tr1, the execution and stop of the valve opening degree are not frequently switched, and the first embodiment The same actions and effects can be obtained.

  In the above embodiment, the case where the control target according to the present invention is PID-controlled has been described as an example. However, the control method may be P (proportional) control or PI (proportional integral) control. In the above embodiment, the pulse motor is exemplified as the actuator. However, the type of the actuator is not limited to the pulse motor, and may be a servo motor or the like. Moreover, although the case where the platinum resistors were used for the temperature sensors 6, 7, and 31 was described, a temperature measuring resistor, a thermocouple, or a thermistor using copper, nickel, or the like can be used for these temperature sensors. .

  Furthermore, in the above-described embodiment, the configuration using the tact switch as the input circuit 15 has been exemplified. However, the present invention is not limited to this, and the input circuit 15 may be configured using a dip switch or provided with a switch. Instead, it may be configured by setting means by communication. In the case where the input circuit 15 is configured by communication setting means, it is possible to input the input value while visually recognizing the set value on the transmission side. Therefore, it is not always necessary to provide the display circuit 16 in the motor-operated valve control device 8. .

It is a block diagram which shows an example of the refrigerating-cycle system using the valve control apparatus concerning this invention. It is a figure which shows an example of the 1st and 2nd temperature range. It is a figure which shows the detailed structural example of the valve control apparatus of FIG. 1, and its peripheral circuit. It is a flowchart for demonstrating the interrupt calculation operation | movement of the valve control apparatus shown in FIG. It is a timing chart showing an example of switching operation between execution and stop of valve opening control. It is the schematic which shows the external appearance of the surface of the main body of the valve control apparatus concerning this invention. It is a flowchart for demonstrating the setting value change operation | movement using the input device of the valve control apparatus concerning this invention. It is a block diagram which shows an example of the hot gas cycle of the refrigerating cycle system using the valve control apparatus concerning this invention. It is a flowchart for demonstrating the interrupt calculation operation | movement of the valve control apparatus shown in FIG. It is a timing diagram which shows the example of switching operation execution and stop of the conventional valve opening control.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Refrigeration cycle system 2 Compressor 3 Condenser 3a Condenser fan 4 Expansion valve 4a Pulse motor 5 Evaporator 5a Evaporator fan 6 Inlet temperature sensor 7 Outlet temperature sensor 8 Electric valve controller 9 Piping 11 Microprocessor 11a A / D conversion 11b CPU
11c ROM
11d RAM
11e Timer 11f I / O
12 Inlet temperature detection circuit 12a Bridge circuit 12b Amplification circuit 13 Outlet temperature detection circuit 13a Bridge circuit 13b Amplification circuit 14 Motorized valve drive circuit 14a Driver IC
15 Input circuit 15a Up switch 15b Down switch 15c Set switch 15d Enter switch 16 Display circuit 16a Temperature display element 16b Valve opening display element 16c LED
17 Display driver circuit 18 Memory circuit 30 Refrigeration cycle system 31 Temperature sensor 32 Flow rate control valve 33 Hot gas bypass piping 34 Hot gas cycle 35 Expansion valve

Claims (6)

In the valve control method for obtaining the deviation between the detected temperature and the target temperature and controlling the valve opening of the valve based on the obtained deviation,
When the detected temperature falls within a first temperature range including the target temperature, control of the valve opening degree of the valve is stopped, and then the detected temperature is the first temperature. The valve control method is characterized in that the control stop of the valve opening degree of the valve is maintained while it is within a second temperature range that includes the range and is wider than the first temperature range. A valve control device that obtains a deviation between a detected temperature and a target temperature and controls the valve opening degree of the valve based on the obtained deviation,
Storage means for storing a first temperature range including the target temperature, and a second temperature range including the first temperature range and wider than the first temperature range;
When the detected temperature falls within the first temperature range, control of the valve opening of the valve is stopped, and thereafter, while the detected temperature is within the second temperature range. And a valve control means for maintaining control stop of the valve opening degree of the valve.   The valve control according to claim 2, wherein the valve control means releases the control stop of the valve opening degree of the valve when the detected temperature is out of the second temperature range. apparatus.   The valve control device according to claim 2 or 3, further comprising setting change means for changing the first and second temperature ranges stored in the storage means.   The valve control device according to claim 2, 3 or 4, wherein the valve is an expansion valve in a refrigeration cycle system, and the detected temperature is a degree of superheat.   5. The valve according to claim 2, 3 or 4, wherein the valve is a flow control valve in a hot gas bypass circuit of a refrigeration cycle system, and the detected temperature is an evaporator temperature or a temperature corresponding thereto. Valve control device.