KR101117249B1 - A multi air conditioner system and electronic expansion valve opening degree control method of the multi air conditioner system - Google Patents

Abstract

The present invention relates to a valve opening control method of a multi-air conditioner system and a multi-air conditioner system in which a plurality of indoor units are connected to one outdoor unit. The purpose is to reduce the time it takes.

To this end, the present invention is a control method of a multi-air conditioner system having a plurality of indoor units and an electromagnetic expansion valve for controlling the superheat degree and the supercooling degree of the refrigerant flowing through the plurality of indoor units, wherein the opening degree of the electromagnetic expansion valve is predetermined. It is determined by adjusting the initial value to determine the optimum opening.If the optimum opening is determined, it is determined whether the current opening degree of the electromagnetic expansion valve is in the initial value range. The opening value of the electromagnetic expansion valve is controlled by correcting the initial value according to the deviation.

Description

A multi air conditioner system and electronic expansion valve opening degree control method of the multi air conditioner system

1 is a graph showing the optimum valve tracking degree of a conventional multi-air conditioner system;

2 is a refrigerant flow path of a multi-air conditioner system according to the present invention;

3 is a control block diagram of a multi-air conditioner system according to an embodiment of the present invention;

4 is an operation flowchart of a valve opening degree control method of a multi-air conditioner system according to the present invention;

5 is a valve opening initial value setting table of a multi-air conditioner system according to the present invention;

6 is a deviation distribution diagram for the valve opening initial value correction in the multi-air conditioner system of the present invention,

7 is a graph showing the optimum valve tracking of the multi-air conditioner system according to the present invention.

Explanation of symbols on the main parts of the drawings

10: outdoor unit 12: compressor

14 four-way valve 16 outdoor heat exchanger

22: outdoor electric valve 30: outside temperature sensor                 

32: outdoor unit controller 50: indoor unit

52: indoor heat exchanger 58: indoor electric valve

60: refrigerant control valve 66: indoor unit control unit

The present invention relates to a multi-air conditioner system for both air conditioning and heating, in which a plurality of indoor units are connected to one outdoor unit, and in particular, a multi air conditioner system for shortening the time taken to track the optimum opening degree of the electronic expansion valve at the start of a change in operation capacity or start of operation. And a valve opening control method of a multi-air conditioner system.

In general, an air conditioner is a device used for cooling or heating indoors, and circulates a refrigerant between an indoor unit and an outdoor unit to absorb ambient heat when the liquid refrigerant evaporates and absorbs the heat when liquefied. Cooling or heating is performed by the releasing property, and cooling or heating of the air conditioner is determined according to the circulation direction of the refrigerant.

A typical air conditioner is to install one indoor unit in one outdoor unit, but recently, a plurality of indoor units having various shapes and capacities are connected to one or more outdoor units to separate a space such as a school, a company, and a building. Increasingly, user demands for multi-system air conditioners, which perform cooling or heating operations for a plurality of places, respectively, are increasing. At this time, the outdoor unit is configured with a capacity proportional to the total capacity of the plurality of indoor units.

In such a multi-air conditioner, the cooling or heating demand for each indoor unit changes according to the change in the environmental characteristics of the place where each indoor unit is installed. Therefore, if the capacity of the indoor unit is changed (when one or more indoor units of the plurality of indoor units are stopped or started) according to this change in capacity, the operating capacity of the compressor is changed, and the opening degree of the electronic expansion valve installed in the outdoor unit is adjusted to the current operating capacity. By adjusting it, it responds.

At this time, time is delayed in tracking the optimum opening of the electronic expansion valve according to the current operating capacity, which leads to the capacity declining section of the multi-air conditioner system. An initial value of the valve opening degree is set and used, and Japanese Patent Application Laid-open No. Hei 9-145130 is used.

The multi-air conditioner system disclosed in this publication controls the opening degree of the electronic expansion valve by using the value calculated by the load constant at the highest air conditioning load and the initial value stored in the memory in order to respond quickly to the change of the compressor operating capacity.

However, such a conventional multi-air conditioner system can shorten the time taken to track the optimum opening degree of the electronic expansion valve under normal conditions such as a test state, but the refrigerant amount is different due to the refrigerant leakage and the refrigerant overfilling, or the state of long piping. The initial value should be changed according to the situation when the pipe length of the pipe is changed or other abnormal conditions occur.However, the initial value cannot be changed by the conventional method. As shown in FIG. 1, there is a problem that the tracking time increases and eventually, the air conditioning capacity decrease of the air conditioner occurs during this time.

Accordingly, the present invention is to solve the above-mentioned conventional problems, an object of the present invention is to change the operating capacity or the multi-air conditioner that can shorten the tracking time it takes for the electromagnetic expansion valve to reach the optimal opening at the start of operation. The present invention provides a method of controlling the valve opening of a system and a multi air conditioner system.

Another object of the present invention is to improve the immersion performance of heating and cooling by minimizing the lowering section of the cooling and heating capacity by controlling the opening degree of the electromagnetic expansion valve to the corrected initial value even when an abnormal condition occurs, thereby reducing the optimal opening tracking time of the electromagnetic expansion valve. To provide a multi-air conditioning system and a valve opening control method of the multi-air conditioning system.

In order to achieve the above object, the present invention provides a control method of a multi-air conditioner system having a plurality of indoor units and an electromagnetic expansion valve for controlling the superheat degree and the supercooling degree of a refrigerant flowing into the plurality of indoor units. The opening degree is adjusted to a predetermined initial value to determine whether the optimum opening degree is determined, and when the optimum opening degree is determined, the current opening degree of the electromagnetic expansion valve is determined to be an initial value range. It calculates and corrects the initial value according to the calculated deviation, It is characterized by controlling the opening degree of the electromagnetic expansion valve.

In the present invention, the method of adjusting the opening degree of the electromagnetic expansion valve to a predetermined initial value may determine whether the plurality of indoor unit capacities have been changed, and if the plurality of indoor unit capacities are changed, the opening degree of the electromagnetic expansion valve according to the changed indoor unit capacities. It characterized in that to adjust to a predetermined initial value.

In the present invention, the method of determining whether the optimum opening degree of the electromagnetic expansion valve is optimal when the degree of superheat and subcooling which changes as the opening degree of the electromagnetic expansion valve is adjusted to an initial value matches the predetermined target superheating degree and the subcooling degree. It is characterized by determining that the opening degree has been reached.

In the present invention, the method for correcting the initial value according to the calculated deviation, by calculating and storing the deviation of the current opening degree of the electronic expansion valve and the predetermined initial value, by performing the operation of calculating and storing the deviation for a set number of times The deviation average is calculated, and the initial deviation is corrected by adding the calculated deviation average to a predetermined initial value.

The deviation average is calculated by averaging deviation within a predetermined control range among deviations of a set number of times.

In addition, the present invention provides a multi-air conditioner system having a plurality of indoor units, the electronic expansion valve for controlling the superheat degree and the supercooling degree of the refrigerant flowing to the plurality of indoor units; And a control unit for controlling whether the plurality of indoor unit capacities have been changed to control the opening degree of the electronic expansion valve.

The controller is characterized in that when the plurality of indoor unit capacity is changed, the opening degree of the electromagnetic expansion valve is controlled to a predetermined initial value according to the changed indoor unit capacity.

The control unit detects whether the operation is started, and when the operation is started, controls the opening degree of the electronic expansion valve to a predetermined initial value.

The controller determines whether the current opening degree of the electromagnetic expansion valve is in a predetermined initial value range when the electromagnetic expansion valve reaches an optimum opening degree, and calculates a deviation between the current opening degree and the initial value when the current opening degree is out of the initial value range. It is characterized by correcting.

When the plurality of indoor unit capacities are changed, the control unit controls the opening degree of the electronic expansion valve to a corrected initial value according to the changed indoor unit capacities.

The electronic expansion valve is characterized in that the outdoor electric valve installed in the outdoor unit.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

2 is a refrigerant flow channel diagram of a multi-air conditioner system according to an exemplary embodiment of the present invention. Cooling or heating may be performed according to a flow direction of a refrigerant, and the present invention will be described with reference to a cooling cycle.

In FIG. 2, the multi-air conditioner system of the present invention includes one outdoor unit 10 forming a conventional refrigerant cycle, and a plurality of indoor units 50 connected in parallel to the outdoor unit 10.

The outdoor unit 10 is a compressor 12 for compressing a refrigerant into a gaseous state of high temperature and high pressure, and the flow direction of the high temperature and high pressure gas refrigerant compressed by the compressor 12 is adjusted in all directions according to an operation mode (cooling or heating). The valve 14, the outdoor heat exchanger 16 which receives the high temperature and high pressure gas refrigerant compressed by the compressor 12 and exchanges heat with the outdoor air, and the outdoor fan motor to perform heat exchange in the outdoor heat exchanger 16. An outdoor fan 18 for forcibly blowing outdoor air by the air 20, and an electromagnetic expansion valve 22 (hereinafter referred to as an outdoor electric valve) for decompressively expanding the heat-exchanged refrigerant while adjusting the refrigerant flow rate.                     

The outdoor electric valve 22 (EEV: Electronic Expansion Valve) adjusts the superheat degree and the supercooling degree of the refrigerant according to its opening degree.

An accumulator 24 is installed at the suction side of the compressor 12 to convert the refrigerant flowing into the compressor 12 into a gas in a completely gaseous state, and the refrigerant pressure discharged from the compressor 12 is provided in the discharge pipe of the compressor 12. A pressure sensor 26 is installed to detect the pressure sensor 26. The pressure sensor 26 may be installed at any position capable of detecting the discharge side pressure of the compressor 12 as well as the discharge pipe of the compressor 12.

An outlet heat sensor 28 for detecting an outlet pipe temperature of the outdoor heat exchanger 16 is installed at an outlet pipe at which refrigerant is discharged during cooling operation among the pipes connected to the outdoor heat exchanger 16. The outdoor heat exchanger outlet temperature sensor 28 may be installed at any position capable of detecting the refrigerant temperature passing through the outdoor heat exchanger 16 as well as the piping of the outdoor heat exchanger 16.

The plurality of indoor units 50 are forcibly blown indoor air by an indoor heat exchanger 52 which receives refrigerant and exchanges heat with the indoor air, and an indoor fan motor 54 to perform heat exchange in the indoor heat exchanger 52. It includes an indoor fan 56 to.

In addition, the inlet-side pipe where the refrigerant is sucked during the cooling operation among the pipes connected to the indoor heat exchanger 52 has an electromagnetic expansion valve 58 (hereinafter referred to as an indoor electric valve) for expanding the refrigerant, and An indoor heat exchanger inlet temperature sensor 62 for detecting an inlet pipe temperature is installed.

The outlet side pipe where the refrigerant is discharged during the cooling operation among the pipes connected to the indoor heat exchanger (52) is a refrigerant control valve (60) for controlling the flow of the refrigerant, and the indoor side of the outlet temperature of the indoor heat exchanger (52). A heat exchanger outlet temperature sensor 64 is installed.

3 is a control configuration diagram of a multi-air conditioner system according to an exemplary embodiment of the present invention, in which the outdoor unit 10 senses the temperature of outdoor air sucked into the outdoor heat exchanger 16 in addition to the apparatus shown in FIG. 2. The sensor 30 further includes an outdoor unit controller 32 for controlling the devices of the outdoor unit 10.

The plurality of indoor units 50 further includes an indoor unit controller 66 for controlling the devices of each indoor unit 50.

Meanwhile, in the present invention, the outdoor unit control unit 32 and the indoor unit control unit 66 are separately described as an example, but the outdoor unit control unit 32 and the indoor unit control unit 66 may be integrally configured according to the specifications or design conditions of the system. have.

Hereinafter, an operation process and an effect of the valve opening degree control method of the multi air conditioner system and the multi air conditioner system configured as described above will be described.

4 is an operation flowchart of a valve opening degree control method of a multi-air conditioner system according to the present invention.

When power is supplied to the outdoor unit 10, the outdoor unit controller 32 checks the operation state of each indoor unit 50 while performing data communication with each indoor unit control unit 66 to determine whether the operation is on (S100). If the operation is not turned on (NO), the opening degree of the outdoor electric valve 22 is completely closed and returned (S101).

If the operation is on (YES), it is determined whether the indoor unit capacity is changed (when at least one indoor unit of the plurality of indoor units is stopped or operation starts) (S110). When the indoor unit capacity is changed (YES), the operating capacity of the compressor 12 is changed, and accordingly, the opening degree of the outdoor electric valve 22 (EEV) should be changed according to the operating capacity of the compressor 12.

At this time, in order to track the optimum opening degree of the outdoor electric valve 22 (EEV) by PID control, the compressor 12 of the digital scroll type requires about 2 to 3 minutes. In order to quickly respond to the change in the driving capacity, the opening degree of the outdoor electric valve 22 (EEV) is set to the initial value shown in FIG. 5 according to the driving capacity (S111). This is the same as the conventional initial value setting method.

If the indoor unit capacity does not change (NO), it is determined whether the initial value of the outdoor motorized valve 22 is set (S120). If the initial value is not set (NO), the opening degree of the outdoor motorized valve 22 is shown. Returning while setting to the initial initial value shown in 5 (S111).

If the initial value of the outdoor electric valve 22 is set (YES), the outdoor electric valve 22 is traced by tracking the state where the target superheat degree and the subcooling degree and the current superheat degree and the subcooling degree predetermined by the initial value and PID control are matched. It is determined whether the optimum opening degree has been reached (S130).

The degree of super heating refers to the difference between the temperature of the superheated steam heated above the saturation temperature and the saturation temperature corresponding to the pressure, but in practice, the outlet temperature and the inlet of the indoor heat exchanger 52 are easy to measure. It is common to control and view the temperature difference as the superheat, and each indoor heat exchanger inlet temperature sensor and outlet temperature sensors 62 and 64 are for measuring the overheat degree of each indoor heat exchanger 52, and each indoor unit 50 is measured. The degree of superheat (indoor heat exchanger outlet temperature-indoor heat exchanger inlet temperature) is also different.                     

Similarly, it is common to control the difference between the discharge pressure of the compressor 12 and the outlet temperature of the outdoor heat exchanger 16, which are easy to measure, by the degree of super cooling, and the pressure sensor of the outdoor unit 10 to perform the control. 26 and the outdoor heat exchanger outlet temperature sensor 28 are for the supercooling measurement of the outdoor heat exchanger 16.

When the superheat degree and the supercooling degree of the refrigerant are high, not only the overheating and the efficiency decrease of the compressor 12 are caused, but when the superheating degree and the supercooling degree are too high, the safety device is activated to stop the operation of the whole system. By managing the supercooling to an appropriate level, it is necessary to maximize the capacity of each indoor unit 50 while reducing the capacity deviation between each indoor unit 50 and increasing the efficiency and stability of the compressor 12 and the entire system.

Accordingly, the optimum opening degree of the outdoor electric valve 22 is changed by PID control until the current superheat degree and the subcooling degree that changes according to the opening degree of the outdoor electric valve 22 coincide with the predetermined target superheat degree and the subcooling degree. It is to determine whether or not to reach, which is the same as the conventional method of reaching the optimum opening by PID control.

The PID control is a control method that uses a combination of three operations of P (proportional), I (integral), and D (derivative) in feedback control, and is a technique commonly used in process control.

If the outdoor motorized valve 22 does not reach the optimum opening degree in step S130 (NO), the target overheating degree and the supercooling degree are tracked by PID calculation based on the deviation of the outdoor temperature and the refrigerant pressure, thereby changing the outdoor electric valve 22 opening degree. It returns while (S131).

When the outdoor electric motor 22 reaches the optimal opening (YES), it is determined whether the opening degree of the outdoor electric motor 22 tracked to the optimal opening coincides with the initial value (S140). It returns while controlling the opening degree of the outdoor motorized valve 22 by PID control (S190).

If the optimal opening does not match the initial value (NO), the deviation between the current opening and the initial value is calculated and stored (S150 to S160).

At this time, the deviation of the current opening value and the initial value can be calculated only at the start of operation or when the capacity is changed, and the process of calculating the deviation is performed for the set number of times (for example, about 10 times) to the previous set number of times (about 10 times). Among the deviations, the deviation average within the control upper limit value and the control lower limit value range shown in FIG. 6 is obtained (S170).

Subsequently, the deviation average is added to the initially set initial value to be corrected to a new initial value (S180), and after that, the opening degree of the outdoor electric valve 22 is controlled by a PID control that tracks the optimum degree with the corrected initial value. (S190).

Therefore, since the opening degree of the outdoor motorized valve 22 is reset according to the characteristics of each indoor unit 50 after the initial value is corrected, the change of the driving capacity in the control method for tracking the optimal opening of the outdoor motorized valve 22 by PID control. Alternatively, it is possible to shorten the time for the outdoor electric valve 22 to go to the optimum opening position, which is the best control position at the start of control, and to correct the new initial value according to the situation even when an abnormal condition different from the test condition occurs. Therefore, the cooling and heating capacity reduction zone is minimized as shown in FIG. 7 as compared with the conventional control, so that the cooling and cooling performance can be improved, and the same cooling and heating effect can be obtained with less time of operation.

What has been described above is only one embodiment for implementing the valve opening degree control method of the multi-air conditioner system and the multi-air conditioner system according to the present invention, the present invention is not limited to the above-described embodiment, it is within the technical idea of the present invention Of course, various modifications are possible by those skilled in the art.

As described above, according to the valve opening degree control method of the multi-air conditioner system and the multi-air conditioner system according to the present invention, it is possible to shorten the tracking time taken for the electromagnetic expansion valve to reach the optimum opening degree at the start of the operation capacity change or operation start. In addition, even if an abnormal condition occurs, the new initial value can be corrected to shorten the tracking time of the optimum opening of the solenoid expansion valve, thereby minimizing the cooling / heating capacity reduction interval, thereby improving the cooling and cooling performance.

Claims (11)

In a control method of a multi-air conditioner system having a plurality of indoor units and an electromagnetic expansion valve for adjusting the superheat degree and the supercooling degree of the refrigerant flowing to the plurality of indoor units, Measuring the superheat degree and the supercooling degree at the current opening degree of the adjusted electromagnetic expansion valve while adjusting the opening degree of the electromagnetic expansion valve, It is determined whether the measured degree of superheat and subcooling at the current opening degree coincides with a predetermined target degree of superheat and subcooling, If the measured degree of superheat and subcooling at the current opening degree coincide with a predetermined target degree of superheat and subcooling, the current opening degree is determined as an optimum opening degree, If the current opening degree is the optimum opening degree, it is determined whether the current opening degree of the electromagnetic expansion valve is a preset initial value range, If the current opening degree is out of the initial value range, the deviation between the current opening degree and the initial value is calculated, Correct the initial value according to the calculated deviation, And controlling the opening degree of the electromagnetic expansion valve based on the corrected initial value. The method of claim 1, It is determined whether the plurality of indoor unit capacity is changed, If the plurality of indoor unit capacity is changed, the valve opening degree control method of the multi-air conditioner system, characterized in that further comprising changing a predetermined initial value according to the changed indoor unit capacity. delete The method of claim 1, The method for correcting the initial value according to the calculated deviation, Calculate and store the deviation between the current opening of the electromagnetic expansion valve and the preset initial value, Calculate and save the deviation for the set number of times to calculate the deviation average, A valve opening control method of a multi-air conditioner system, characterized in that the initial value is corrected by adding the calculated deviation average to a preset initial value. The method of claim 4, wherein And the deviation average is calculated by averaging deviation within a predetermined control range among deviations of a set number of times. In the multi-air conditioner system having a plurality of indoor units, An electronic expansion valve configured to adjust the superheat degree and the supercooling degree of the refrigerant flowing to the plurality of indoor units; And Detecting whether the plurality of indoor unit capacities are changed, and when the plurality of indoor unit capacities are changed, an initial value is set according to the changed indoor unit capacities, and the superheat degree at the current opening degree of the adjusted electromagnetic expansion valve is adjusted while adjusting the opening degree of the electromagnetic expansion valve. And measuring the degree of subcooling, and if the measured degree of superheat and subcooling at the current opening degree coincide with a predetermined target degree of superheat and subcooling, the present opening degree is determined to be the optimum opening degree, and it is determined whether the current opening degree is the initial value, If the current opening degree is out of the initial value range, the opening degree of the electromagnetic expansion valve is controlled based on the deviation between the current opening degree and the initial value, and if the current opening degree is an initial value range, Multi-air conditioner system comprising a control unit for controlling the opening degree. delete The method of claim 6, The control unit detects whether the operation is started, the multi-air conditioner system, characterized in that for controlling the opening degree of the electronic expansion valve to a predetermined initial value when the operation starts. delete The method of claim 6, The control unit calculates a deviation between the current opening degree and the initial value when the current opening degree is out of an initial value range, corrects the initial value, and controls the opening degree of the electronic expansion valve using the corrected initial value. system. The method of claim 6, The electronic expansion valve is a multi-air conditioning system, characterized in that the outdoor electric valve installed in the outdoor unit.

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