Multi-split machine heating control method, machine readable storage medium and multi-split machine

Abstract

The invention relates to the technical field of air treatment equipment, in particular to a multi-split machine heating control method, a machine readable storage medium and a multi-split machine. The control method comprises the following steps that the starting-up capacity of the indoor unit is obtained; in response to the condition that the compressor reaches the target operation frequency and lasts for a preset duration, the actual exhaust temperature of the compressor is obtained, and the actual exhaust temperature is compared with the threshold range of the exhaust temperature; if the actual exhaust temperature is within the threshold range, the suction pressure of the compressor is obtained; and the target suction superheat degree of the compressor is obtained according to the starting capacity and the suction pressure. According to the method, on the premise of ensuring the reliability of the compressor, the operation working condition of the compressor is comprehensively judged according to the starting capacity and the suction pressure, different self-adaptive target suction superheat degree control is carried out according to the working condition change, reasonable control over the main throttle valve is achieved, and the reliability of the compressor is improved. Therefore, efficient and stable operation of the compressor under all working conditions and energy conservation and consumption reduction of the whole multi-split air conditioning system are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of air handling equipment, and particularly to a heating control method for a multi-connected unit, a machine-readable storage medium, and a multi-connected unit. Background Art

[0002] Currently, a multi-connected unit air conditioning system is a model in which one outdoor unit is connected to several indoor units through pipes. It has the advantages of convenient installation and good refrigeration effect, and is widely used in commercial buildings such as office buildings and apartments, and can meet the refrigeration / heating needs of multiple indoor places at the same time.

[0003] Generally, a main throttle valve is provided in the multi-connected unit system. By adjusting the opening degree of the main throttle valve, the flow rate of the refrigerant can be adjusted and its pressure can be reduced. Its opening degree directly affects the heating capacity and energy efficiency of the multi-connected unit system. Therefore, in the multi-connected unit system, the control logic of the opening degree of the main throttle valve is extremely important. The appropriate valve opening degree under different working conditions is an important basis for achieving the high energy efficiency goal of the multi-connected unit.

[0004] Currently, in the heating mode, the opening degree of the main throttle valve is controlled by the target suction superheat. Under normal conditions (exhaust temperature, subcooling degree, etc. are within the normal range), the target suction superheat is set to a fixed value, generally 4 - 6°C. When the actual suction superheat is greater than the target suction superheat, the main throttle valve is corrected positively to increase the opening degree to reduce the actual suction superheat to the target value. When the actual suction superheat is less than the target suction superheat, the main throttle valve is corrected reversely to decrease the opening degree to increase the superheat to the target value. The superheat affects the energy efficiency of the compressor, and thus affects the energy efficiency of the entire multi-connected unit system. However, the optimal target suction superheat corresponding to the compressor is different under different working conditions. Setting the target suction superheat to a fixed value cannot meet the requirements of the compressor for efficient operation under various working conditions. Summary of the Invention

[0005] In view of the above problems, the present invention is proposed to provide a heating control method for a multi-connected unit, a machine-readable storage medium, and a multi-connected unit that can overcome or at least partially solve the above problems, aiming to solve the problem that the existing multi-connected unit controls the main throttle valve according to a fixed target suction superheat, resulting in the compressor not being able to meet the requirements of efficient operation under various working conditions, so as to achieve different adaptive target suction superheat control according to the change of working conditions, thereby realizing the efficient and stable operation of the compressor under all working conditions and the energy conservation and consumption reduction of the entire multi-connected unit.

[0006] On the one hand, the present invention provides a heating control method for a multi-connected unit, including:

[0007] Obtain the starting capacity of the indoor unit;

[0008] In response to the compressor reaching the target operating frequency and lasting for a preset duration, obtain the actual exhaust temperature of the compressor, and compare the actual exhaust temperature with the threshold range of the exhaust temperature;

[0009] If the actual exhaust temperature is within the threshold range, obtain the suction pressure of the compressor;

[0010] Obtain the target suction superheat of the compressor according to the starting capacity and the suction pressure.

[0011] Optionally, multiple preset suction pressure intervals, multiple preset starting capacity intervals, and multiple preset suction superheats are preset in the multi-connected unit;

[0012] The obtaining the target suction superheat according to the starting capacity and the suction pressure includes:

[0013] Judge the preset suction pressure interval where the starting capacity is located and the preset starting capacity interval where the starting capacity is located, and use the preset suction superheat corresponding to the preset suction pressure interval and the preset starting capacity interval as the target suction superheat.

[0014] Optionally, the heating control method of the multi-connected unit further includes:

[0015] If the actual exhaust temperature is less than the lower limit value of the threshold range, use the first superheat value as the target suction superheat of the compressor; and / or

[0016] If the actual exhaust temperature is greater than the upper limit value of the threshold range, use the second superheat value as the target suction superheat of the compressor;

[0017] Wherein, the second superheat value is less than the first superheat value.

[0018] Optionally, the heating control method of the multi-connected unit further includes:

[0019] In response to obtaining the target suction superheat, obtain the actual suction superheat of the compressor;

[0020] Control the opening degree of the main throttle valve according to the target suction superheat and the actual suction superheat.

[0021] Optionally, after controlling the opening degree of the main throttle valve according to the target suction superheat and the actual suction superheat, it further includes: executing the step of obtaining the actual exhaust temperature of the compressor every first duration; and / or

[0022] After controlling the opening degree of the main throttle valve according to the target suction superheat and the actual suction superheat, it further includes: executing the step of obtaining the starting capacity of the indoor unit every second duration.

[0023] Optionally, obtaining the actual suction superheat degree of the compressor includes:

[0024] Obtaining the suction pressure of the compressor;

[0025] Obtaining the saturated suction temperature at least according to the suction pressure;

[0026] Obtaining the temperature of the condenser outlet pipe;

[0027] Calculating the difference between the saturated suction temperature and the temperature of the condenser outlet pipe to obtain the actual suction superheat degree;

[0028] Wherein, obtaining the saturated suction temperature at least according to the suction pressure includes:

[0029] Obtaining the saturated suction temperature according to the suction pressure; or

[0030] Obtaining the pressure loss of the refrigerant from the outlet of the gas separator to the inlet of the compressor to obtain the suction pressure drop;

[0031] Obtaining the saturated suction temperature according to the suction pressure and the suction pressure drop.

[0032] Optionally, the calculation formula of the suction pressure drop is:

[0033]

[0034] Wherein, △P is the suction pressure drop;

[0035] L is the pipeline length from the outlet of the gas separator to the inlet of the compressor;

[0036] D is the inner diameter of the pipeline from the outlet of the gas separator to the inlet of the compressor.

[0037] Optionally, the multi-connected unit heating control method further includes:

[0038] The outdoor unit receives the startup signal transmitted by the indoor unit; in response to the startup signal, execute the step of obtaining the startup capacity of the indoor unit;

[0039] Obtaining the set temperature of the started indoor unit and the outdoor ambient temperature;

[0040] Obtaining the target operating frequency of the compressor according to the startup capacity, the set temperature of the started indoor unit and the outdoor ambient temperature;

[0041] Controlling the compressor to start and increase the frequency to the target operating frequency.

[0042] On the other hand, the present invention also provides a machine-readable storage medium, on which a machine-executable program is stored. When the machine-executable program is executed by a processor, the multi-connected unit heating control method as described in any one of the above is implemented.

[0043] On the other hand, the present invention also provides a multi-connected air conditioner, including a controller, the controller includes a memory, a processor, and a machine-executable program stored on the memory and running on the processor, and when the processor executes the machine-executable program, it realizes the multi-connected air conditioner heating control method as described in any one of the above.

[0044] In the multi-connected air conditioner heating control method, machine-readable storage medium, and multi-connected air conditioner of the present invention, when the compressor reaches the target operating frequency and lasts for a preset duration, and the exhaust temperature is within the threshold range, the target suction superheat is obtained according to the starting capacity and the suction pressure, and the target suction superheat is a floating value. That is to say, on the premise of ensuring the reliability of the compressor, the present invention comprehensively determines the operating condition of the compressor according to the starting capacity and the suction pressure, and performs different adaptive target suction superheat controls according to the change of the condition, realizes the reasonable control of the main throttle valve, and thus realizes the efficient and stable operation of the compressor under all conditions and the energy saving and consumption reduction of the entire multi-connected air conditioner system.

[0045] In addition, the control method of the present invention has the beneficial effect that the control program is simple and easy to execute.

[0046] Therefore, according to the following detailed description of the specific embodiments of the present invention in conjunction with the drawings, those skilled in the art will be more clear about the above and other objects, advantages, and features of the present invention. Description of the Drawings

[0047] Some specific embodiments of the present invention will be described in detail hereinafter with reference to the drawings in an exemplary but not restrictive manner. The same reference numerals in the drawings denote the same or similar components or parts. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings:

[0048] Figure 1 is a schematic flow chart of a multi-connected air conditioner heating control method according to an embodiment of the present invention;

[0049] Figure 2 is a schematic flow chart of a multi-connected air conditioner heating control method according to an embodiment of the present invention;

[0050] Figure 3 is a schematic flow chart of a multi-connected air conditioner heating control method according to an embodiment of the present invention;

[0051] Figure 4 is a schematic flow chart of a multi-connected air conditioner heating control method according to an embodiment of the present invention;

[0052] Figure 5 is a schematic flow chart of a multi-connected air conditioner heating control method according to an embodiment of the present invention;

[0053] Figure 6 is a schematic flowchart of a multi - unit heating control method according to an embodiment of the present invention;

[0054] Figure 7 is a schematic flowchart of a multi - unit heating control method according to an embodiment of the present invention;

[0055] Figure 8 is a schematic flowchart of a multi - unit heating control method according to an embodiment of the present invention;

[0056] Figure 9 is a schematic flowchart of a multi - unit heating control method according to an embodiment of the present invention;

[0057] Figure 10 is a schematic structural diagram of a machine - readable storage medium according to an embodiment of the present invention;

[0058] Figure 11 is a schematic structural diagram of a multi - unit air conditioner according to an embodiment of the present invention;

[0059] Figure 12 is a schematic diagram of the heating working principle of a multi - unit air conditioner according to an embodiment of the present invention. Detailed Embodiments

[0060] The following refers to Figures 1 to 12 to describe the multi - unit heating control method, machine - readable storage medium and multi - unit air conditioner of the embodiments of the present invention. Among them, the orientation or positional relationship indicated by "front", "rear", "upper", "lower", "top", "bottom", "inner", "outer", "lateral", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation of the present invention.

[0061] The terms "first", "second", etc. are only used for descriptive purposes, and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first", "second", etc. may explicitly or implicitly include at least one of such features, that is, include one or more of such features. In the description of the present invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise specifically defined. When a certain feature "includes or contains" a certain or certain features it covers, unless otherwise specifically described, this indicates that other features are not excluded and other features may be further included.

[0062] Unless otherwise clearly defined and limited, terms such as "installation", "connection", "coupling", "fixing", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two components or the interaction relationship between two components, unless otherwise clearly limited. Those of ordinary skill in the art should be able to understand the specific meanings of the above terms in the present invention according to specific circumstances.

[0063] Figure 1 is a schematic flowchart of a multi - unit heating control method according to an embodiment of the present invention, and in combination with Figures 2 - 9 The present invention provides a multi - unit heating control method, including the following steps:

[0064] S200, obtain the startup capacity of the indoor unit;

[0065] S300, in response to the compressor reaching the target operating frequency and lasting for a preset duration, obtain the actual exhaust temperature of the compressor, and compare the actual exhaust temperature with the threshold range of the exhaust temperature;

[0066] S400, if the actual exhaust temperature is within the threshold range, obtain the suction pressure of the compressor;

[0067] S500, obtain the target suction superheat of the compressor according to the startup capacity and the suction pressure.

[0068] Specifically, there is no sequential order between S200 and S400. In S200, the startup capacity of the indoor unit is equal to the ratio of the number of started indoor units to the total number of indoor units, and the calculation formula is: The above - mentioned number of started indoor units does not include the indoor units that enter the standby state (them off) because the indoor temperature reaches the set temperature. In S300, the preset duration can be 2 - 50S, preferably 5s. In S400, the threshold range refers to the normal range of the exhaust temperature; "obtain the suction pressure of the compressor" means obtaining the suction pressure Ps according to the suction pressure sensor on the suction pipe of the gas - liquid separator. When the compressor reaches the target operating frequency and lasts for a preset duration, and the exhaust temperature is within the normal range of the exhaust temperature, it indicates that the compressor is in a stable state at this time.

[0069] This embodiment proposes a variable target superheat control method. When the compressor reaches the target operating frequency and lasts for a preset duration, and the exhaust temperature is within the threshold range, the target suction superheat is obtained based on the starting capacity and the suction pressure, and the target suction superheat is a floating value. That is to say, on the premise of ensuring the reliability of the compressor, this method comprehensively determines the operating conditions of the compressor according to the starting capacity and the suction pressure, and performs different adaptive target suction superheat controls according to the changes in the conditions, realizing the reasonable control of the main throttle valve, thereby achieving the efficient and stable operation of the compressor under all conditions and the energy saving and consumption reduction of the entire multi-connected unit system.

[0070] In some alternative embodiments of the present invention, multiple preset suction pressure intervals, multiple preset starting capacity intervals, and multiple preset suction superheats are preset in the multi-connected unit.

[0071] As Figure 2 shown, S500, obtaining the target suction superheat according to the starting capacity and the suction pressure includes: determining the preset suction pressure interval where the starting capacity is located and the preset starting capacity interval where the starting capacity is located, and taking the preset suction superheat corresponding to the preset suction pressure interval and the preset starting capacity interval as the target suction superheat.

[0072] In this embodiment, a target suction superheat determination table is preset in the multi-connected unit. In this table, corresponding preset suction superheats are preset for different preset suction pressure intervals and different preset starting capacity intervals. The above target suction superheat determination table can be as shown in Table 1 below:

[0073] Table 1 Target suction superheat determination table

[0074]

[0075] Since the above target suction superheat determination table is preset in this embodiment, the target suction superheat suitable for the current compressor conditions can be quickly obtained by using the above table, thereby improving the control efficiency of the main throttle valve. In some other embodiments of the present invention, the division of the suction pressure interval, the division of the starting capacity interval, and the values of the preset suction superheat in the target suction superheat determination table can also be in other forms. That is to say, the above target suction superheat determination table is not unique and can be set according to specific needs.

[0076] In another alternative embodiment of the present invention, the target suction superheat determination table can be as shown in Table 2 below:

[0077] Table 2 Target suction superheat determination table

[0078]

[0079] In some alternative embodiments of the present invention, in S500, obtaining the target suction superheat degree according to the starting capacity and the suction pressure includes: obtaining the target suction superheat degree according to the starting capacity, the suction pressure and the corresponding algorithm.

[0080] In some optional embodiments of the present invention, the multi-connected unit heating control method further includes: S401, if the actual exhaust temperature is less than the lower limit value of the threshold range, then use the first superheat degree value as the target suction superheat degree of the compressor. Specifically, when the actual exhaust temperature is less than the lower limit value of the threshold range, at this time, the compressor has a risk of liquid return. Set the target suction superheat degree to the first superheat degree value, and this first superheat degree value is a fixed value. Subsequently, obtain the actual suction superheat degree, calculate the difference between the actual suction superheat degree and the target suction superheat degree, and close the main throttle valve according to the difference to increase the actual suction superheat degree and prevent liquid return. The first superheat degree value can be set as needed; preferably, the first superheat degree value is greater than 6°C (for example: the first superheat degree value can be 6.1°C, 6.5°C, 7°C, 7.5°C or 8°C); more preferably, the first superheat degree value is 8°C.

[0081] In some optional embodiments of the present invention, the multi-connected unit heating control method further includes: S402, if the actual exhaust temperature is greater than the upper limit value of the threshold range, then use the second superheat degree value as the target suction superheat degree of the compressor. Specifically, when the actual exhaust temperature is greater than the upper limit value of the threshold range, the exhaust temperature in this interval is too high, and the compressor has a risk of overcurrent burnout. Set the target suction superheat degree to the second superheat degree value, and this second superheat degree value is a fixed value. Subsequently, obtain the actual suction superheat degree, calculate the difference between the actual suction superheat degree and the target suction superheat degree, and increase the opening of the main throttle valve according to the difference. The second superheat degree value can be set as needed, for example, the second superheat degree value is less than 2°C. Preferably, the second superheat degree value is 0.5 - 1.9°C (for example: the second superheat degree value can be 0.5°C, 0.8°C, 1°C, 1.5°C or 1.9°C); more preferably, the second superheat degree value is 1°C.

[0082] As Figure 3 shown, in some optional embodiments of the present invention, the multi-connected unit heating control method further includes:

[0083] S401, if the actual exhaust temperature is less than the lower limit value of the threshold range, then use the first superheat degree value as the target suction superheat degree of the compressor;

[0084] S402, if the actual exhaust temperature is greater than the upper limit value of the threshold range, then use the second superheat degree value as the target suction superheat degree of the compressor.

[0085] Among them, the second superheat value is less than the first superheat value. Specifically, when the actual exhaust gas temperature is less than the lower limit value of the threshold range, there is a risk of liquid return in the compressor at this time, and the target suction superheat is set to the first superheat value, which is a fixed value. Subsequently, the actual suction superheat is obtained, and the difference between the actual suction superheat and the target suction superheat is calculated. According to the difference, the main throttle valve is closed to increase the actual suction superheat and prevent liquid return. When the actual exhaust gas temperature is greater than the upper limit value of the threshold range, the exhaust gas temperature in this interval is too high, and there is a risk of overcurrent burnout of the compressor. The target suction superheat is set to the second superheat value, which is a fixed value. Subsequently, the actual suction superheat is obtained, and the difference between the actual suction superheat and the target suction superheat is calculated. According to the difference, the opening degree of the main throttle valve is increased. The first superheat value can be set as needed; preferably, the first superheat value is greater than 6 °C (for example: the first superheat value can be 6.1 °C, 6.5 °C, 7 °C, 7.5 °C or 8 °C); more preferably, the first superheat value is 8 °C. The second superheat value can be set as needed, for example, the second superheat value is less than 2 °C. Preferably, the second superheat value is 0.5 - 1.9 °C (for example: the second superheat value can be 0.5 °C, 0.8 °C, 1 °C, 1.5 °C or 1.9 °C); more preferably, the second superheat value is 1 °C.

[0086] As Figure 4 shown, in some alternative embodiments of the present invention, the multi - split heating control method further includes:

[0087] S600, in response to obtaining the target suction superheat, obtain the actual suction superheat of the compressor;

[0088] S700, control the opening degree of the main throttle valve according to the target suction superheat and the actual suction superheat.

[0089] Further, as Figure 5 shown, in some alternative embodiments of the present invention, step S700 specifically includes the following steps: S701, calculate the suction superheat difference between the target suction superheat and the actual suction superheat; S702, control the opening degree of the main throttle valve according to the suction superheat difference. Specifically, the suction superheat difference = |target suction superheat - actual suction superheat|.

[0090] S702 includes the following three cases:

[0091] In the case where the actual exhaust gas temperature is within the threshold range, if the actual superheat - target suction superheat > 0, then reduce the opening degree of the main throttle valve; if the actual superheat - target suction superheat < 0, then increase the opening degree of the main throttle valve.

[0092] In the case where the actual exhaust gas temperature is less than the lower limit value of the threshold range, according to the suction superheat difference, close the opening degree of the main throttle valve.

[0093] When the actual exhaust temperature is greater than the upper limit value of the threshold range, the opening degree of the main throttle valve is increased according to the difference in suction superheat.

[0094] In some alternative embodiments of the present invention, in S702, the adjustment rate of the opening degree of the main throttle valve is positively correlated with the difference in suction superheat. That is to say, the greater the difference in suction superheat, the greater the adjustment rate of the opening degree of the main throttle valve; the smaller the difference in suction superheat, the smaller the adjustment rate of the opening degree of the main throttle valve. By the above method, when the exhaust temperature is too high or too low, accelerating the adjustment rate of the opening degree of the main throttle valve can protect the compressor and prevent control oscillation caused by excessive actions.

[0095] For example, when increasing the opening degree of the main throttle valve, when the difference in suction superheat is greater than 2°C, the valve opening rate is 20 pls / s; when the difference in suction superheat is less than 2°C and greater than 1°C, the valve opening rate is 10 pls / s, and when the difference in suction superheat is less than 1°C, the valve opening rate is 5 pls / s.

[0096] In some alternative embodiments of the present invention, in S700, after controlling the opening degree of the main throttle valve according to the target suction superheat and the actual suction superheat, the multi-connected unit heating control method further includes: performing the step of obtaining the actual exhaust temperature of the compressor once every first time period.

[0097] In this embodiment, the target suction superheat can be adaptively adjusted according to the change in the exhaust temperature of the compressor, which is more conducive to the precise control of the main throttle valve, and thus more conducive to the efficient and stable operation of the compressor under all working conditions and the energy saving and consumption reduction of the entire multi-connected unit system. Further, the first time period can be set as needed; preferably, the first time period can be 5 to 20 seconds (for example: the first time period can be 5 seconds, 8 seconds, 10 seconds, 15 seconds or 20 seconds); more preferably, the first time period is 10 seconds.

[0098] In some alternative embodiments of the present invention, in step S700, after controlling the opening degree of the main throttle valve according to the target suction superheat and the actual suction superheat, the multi-connected unit heating control method further includes: performing the step of obtaining the starting capacity of the indoor unit once every second time period.

[0099] This embodiment can adaptively adjust the target suction superheat according to the change in the starting capacity, which is more conducive to the precise control of the main throttle valve, and thus more conducive to the efficient and stable operation of the compressor under all working conditions and the energy saving and consumption reduction of the entire multi-connected unit system. Further, the second time period can be set as needed; preferably, the second time period can be 40 to 70 seconds (for example: the second time period can be 41 seconds, 45 seconds, 50 seconds, 55 seconds, 60 seconds, 65 seconds or 70 seconds); more preferably, the second time period is 60 seconds.

[0100] As shown Figure 6 In some alternative embodiments of the present invention, in S600, obtaining the actual suction superheat of the compressor may specifically include the following steps:

[0101] S601, obtaining the suction pressure of the compressor;

[0102] S602, obtaining the saturated suction temperature at least according to the suction pressure;

[0103] S603, obtaining the temperature of the condenser outlet pipe;

[0104] S604, calculating the difference between the saturated suction temperature and the temperature of the condenser outlet pipe to obtain the actual suction superheat.

[0105] Specifically, a suction pressure sensor is provided on the intake pipe of the gas-liquid separator to obtain the suction pressure, specifically the saturated pressure Ps. This embodiment provides a specific method for obtaining the actual suction superheat of the compressor. According to the above method, the actual suction superheat can be obtained quickly and accurately, which is beneficial to quickly and accurately control the main throttle valve.

[0106] In some alternative embodiments of the present invention, in S602, obtaining the saturated suction temperature at least according to the suction pressure may include: obtaining the saturated suction temperature according to the suction pressure. Specifically, in the heating condition, the refrigerant is throttled and depressurized by the main throttle valve in the outdoor unit, and the main throttle valve is controlled by the actual suction superheat. The actual suction superheat is defined as SH = Ts - Toci, where Ts is the saturated suction temperature obtained by fitting according to the saturated pressure Ps obtained by the suction pressure sensor and based on the characteristics of the circulating refrigerant, and Toci is the temperature obtained by the temperature sensor arranged on the condenser outlet pipe.

[0107] As shown Figure 7 In some alternative embodiments of the present invention, in S602, obtaining the saturated suction temperature at least according to the suction pressure may include the steps of:

[0108] S6021, obtaining the pressure loss of the refrigerant from the outlet of the gas-liquid separator to the inlet of the compressor to obtain the suction pressure drop;

[0109] S6022, obtaining the saturated suction temperature according to the suction pressure and the suction pressure drop.

[0110] Specifically, in the heating mode, the refrigerant is throttled and depressurized by the main throttle valve inside the outdoor unit. The main throttle valve is controlled by the actual suction superheat degree, and the actual suction superheat degree is defined as SH = Ts - Toci, where Ts = f(Ps + △P), f is the fitting relationship corresponding to the saturated pressure and saturated temperature of the refrigerant, △P is the suction pressure drop, and Toci is the temperature obtained by the temperature sensor arranged on the condenser outlet pipe. In this embodiment, a more accurate saturated suction temperature can be obtained based on the suction pressure drop and the suction pressure, thereby improving the control accuracy of the main throttle valve and avoiding the problem of too large or too small valve opening caused by the resistance loss of the suction pipe section.

[0111] Further, in some alternative embodiments of the present invention, the calculation formula for the suction pressure drop is:

[0112]

[0113] where, △P is the suction pressure drop; L is the pipeline length from the outlet of the gas separator to the inlet of the compressor; D is the inner diameter of the pipeline from the outlet of the gas separator to the inlet of the compressor.

[0114] This embodiment provides a specific formula for obtaining the suction pressure drop. The above formula takes L and D as design variables. Since it is convenient to obtain the accurate values of L and D, the suction pressure drop can be obtained quickly and accurately by using the above formula, thereby the actual suction superheat degree can be obtained quickly and accurately, and further the control accuracy of the main throttle valve can be improved. In some alternative embodiments, other algorithms or methods can also be used to obtain the suction pressure drop.

[0115] As Figure 8 shown, in some alternative embodiments of the present invention, the multi - split system heating control method further includes the following steps:

[0116] S101, the outdoor unit receives the start signal transmitted by the indoor unit; in response to the start signal, execute S200 and S102;

[0117] S102, obtain the set temperature of the started indoor unit and the outdoor ambient temperature;

[0118] S103, obtain the target operating frequency of the compressor according to the start - up capacity, the set temperature of the started indoor unit and the outdoor ambient temperature;

[0119] S104, control the compressor to start and increase the frequency to the target operating frequency.

[0120] Specifically, in S103, where, Qc: the required output capacity of the compressor; Kc: the outdoor ambient temperature correction coefficient; K i,j : the indoor ambient temperature correction coefficient of the j - th started indoor unit; Q i,j; the capacity of the j-th turned-on indoor unit.

[0121] Further, the value of Kc is divided according to the outdoor ambient temperature, and Kc is negatively correlated with the outdoor ambient temperature; the higher the outdoor ambient temperature, the smaller the value of Kc; the lower the outdoor ambient temperature, the smaller the value of Kc. K i,j is valued according to the magnitude of Δt j . Specifically, Δt j = T ai,j - T set,j , where T ai,j is the indoor ambient temperature corresponding to the j-th turned-on indoor unit, and T set,j is the set temperature of the j-th turned-on indoor unit; K i,j is positively correlated with Δt j . The larger Δt j , the larger the value of K i,j ; conversely, the smaller Δt j , the smaller the value of K i,j . Even further, according to the difference between the indoor ambient temperature and the set temperature corresponding to the j-th turned-on indoor unit, and the difference between the outdoor ambient temperature and the set temperature, K i,j is obtained; specifically, K i,j =(T ai,j - T set,j ) / (T ao - T set,j ); Tao is the outdoor ambient temperature.

[0122] Specifically, S104: Control the compressor to start, and increase the frequency to the target frequency at a fixed frequency according to the compressor start-up logic, where the fixed frequency of frequency increase can be 2 rps / s or 4 rps / s or 6 rps / s, and the specific value needs to be determined in combination with the capacity and structure of the compressor itself.

[0123] In a preferred embodiment of the present invention, as Figure 12 shown, the multi-connected air conditioner 100 is composed of an indoor unit 120 and an outdoor unit 110. The main components of the outdoor unit 110 include a compressor 111, an oil separator 112, a four-way valve 113, a condenser 114, a main throttle valve 115, a plate heat exchanger 116, and a gas-liquid separator 117. Each component is connected through a pipeline to realize the refrigerant cycle. In the heating working condition, the refrigerant is throttled and depressurized by the main throttle valve in the outdoor unit, and the main throttle valve is controlled by the suction superheat. A suction pressure sensor 118 is provided on the intake pipe of the gas-liquid separator 117; a temperature sensor 119 is provided on the outlet pipe of the condenser.

[0124] As Figure 9 shown, a multi-connected air conditioner heating control method includes the following steps:

[0125] S1, The outdoor unit receives the startup signal transmitted by the indoor unit; when the outdoor unit receives the startup signal, S2 is executed.

[0126] S2, The indoor unit communicates with the outdoor unit to obtain the number of startup indoor units and calculate the startup capacity of the current indoor unit.

[0127] S3, Obtain the outdoor ambient temperature and the set temperature of the started indoor units.

[0128] S4, Obtain the target operating frequency of the compressor based on the startup capacity, the set temperature of the started indoor units, and the outdoor ambient temperature.

[0129] S5, Determine the target superheat load zone where the startup capacity is located; specifically, based on the current startup capacity and combined with the target suction superheat determination table (such as Table 1), determine the target superheat load zone where the current startup capacity is located. For example, when the startup capacity is 100%, the current target superheat load zone is Zone A; when the startup capacity is 80%, the current target superheat load zone is Zone B. In addition, when the startup capacity is not within Table 1, the rounding-up method is used for determination. For example, when the startup capacity is 95%, it is rounded up to 100%; when the startup capacity is 84%, it is rounded up to 80%.

[0130] S6, Control the compressor to start and increase the frequency to the target operating frequency. After the compressor reaches the target operating frequency, it continues to operate at the target operating frequency for a preset duration.

[0131] S7, Obtain the exhaust temperature Td of the current compressor, and compare the actual exhaust temperature with the threshold range of the exhaust temperature; if the actual exhaust temperature is within the threshold range, S8 is executed; if the actual exhaust temperature is less than the lower limit of the threshold range, S9 is executed; if the actual exhaust temperature is greater than the upper limit of the threshold range, S10 is executed.

[0132] S8, Obtain the suction pressure of the compressor; after S8, S11 is executed.

[0133] S9, Assign the target suction superheat to the first superheat value. After S9, S12 is executed. Preferably, the first superheat value is greater than 6°C. More preferably, the first superheat value is 8°C.

[0134] S10, Assign the target suction superheat to the second superheat value; after S10, S12 is executed. Preferably, the second superheat value is less than 2°C. More preferably, the second superheat value is 1°C.

[0135] S11. Determine the target suction superheat degree corresponding to the compressor under the current operating condition based on the target superheat load zone determined by S5, the current suction pressure, and the target suction superheat degree determination table. For example, if it is determined by S5 that the target superheat load zone belongs to Zone B, a < Ps < b, according to Table 1, it can be known that the corresponding target suction superheat degree value is B2. After S11, execute S12.

[0136] S12. Obtain the actual suction superheat degree of the compressor.

[0137] S13. Calculate the difference in suction superheat degree between the target suction superheat degree and the actual suction superheat degree.

[0138] S14. Control the opening degree of the main throttle valve according to the difference in suction superheat degree. After S14, execute S7 once every first time period, and execute S2 once every first time period. The first time period is less than the second time period.

[0139] In this embodiment, during the process of running steps S1 to S7, the target suction superheat degree is a fixed value. During the process of running steps S8 to S14, the target suction superheat degree is a variable value.

[0140] Furthermore, S12 includes the following steps: Obtain the suction pressure of the compressor; obtain the pressure loss of the refrigerant from the outlet of the gas separator to the inlet of the compressor to obtain the suction pressure drop; obtain the saturated suction temperature according to the suction pressure and the suction pressure drop; obtain the temperature of the condenser outlet pipe; calculate the difference between the saturated suction temperature and the temperature of the condenser outlet pipe to obtain the actual suction superheat degree.

[0141] In this embodiment, on the one hand, this embodiment proposes a variable superheat control method. Under the premise of ensuring the reliability of the compressor, according to the starting capacity and the suction pressure of the compressor, comprehensively determine the operating condition range in which the compressor is located, and perform different adaptive target superheat control according to the change of the operating condition, realizing the efficient and stable operation of the compressor under all operating conditions and the energy saving and consumption reduction of the entire multi-connected unit system. On the other hand, in this embodiment, a more accurate saturated suction temperature can be obtained according to the suction pressure drop and the suction pressure, thereby improving the control accuracy of the main throttle valve and avoiding the problem of too large or too small valve opening caused by the resistance loss of the suction pipe section.

[0142] Figure 10 It is a schematic diagram of a machine-readable storage medium 200 according to an embodiment of the present invention. As Figure 10 shown, the embodiment of the present invention also provides a machine-readable storage medium 200, on which a machine-executable program 201 is stored. When the machine-executable program 201 is executed by a processor 132, it realizes the multi-connected unit heating control method according to any one of the above embodiments.

[0143] It should be noted that the logic and / or steps represented in the flowchart or described in other ways herein, for example, can be considered as a definite sequence list of executable instructions for implementing logical functions, and can be specifically implemented in any machine-readable storage medium 200 for use by an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor 132, or other systems that can fetch and execute instructions from the instruction execution system, apparatus, or device), or used in combination with these instruction execution systems, apparatus, or devices.

[0144] For the description of this embodiment, the machine-readable storage medium 200 can be any device that can contain, store, communicate, propagate, or transmit a program for use by an instruction execution system, apparatus, or device or in combination with these instruction execution systems, apparatus, or devices. More specific examples (non-exhaustive list) of the machine-readable storage medium 200 include the following: an electrical connection part (electronic device) having one or more wirings, a portable computer disk cartridge (magnetic device), a random access memory 131 (RAM), a read-only memory 131 (ROM), an erasable programmable read-only memory 131 (EPROM or flash memory 131), an optical fiber device, and a portable compact disc read-only memory 131 (CDROM). Additionally, the machine-readable storage medium 200 can even be paper or other suitable media on which the program can be printed, because the program can be obtained electronically, for example, by optically scanning the paper or other media, followed by editing, interpretation, or other suitable processing as necessary, and then stored in the memory 131.

[0145] Figure 11 is a schematic diagram of a multi-connected air conditioner 100 according to an embodiment of the present invention, as Figure 11 shown, an embodiment of the present invention further provides a multi-connected air conditioner 100, and the multi-connected air conditioner 100 includes a controller 130. The controller 130 includes a memory 131, a processor 132, and a machine-executable program 201 stored on the memory 131 and running on the processor 132. When the processor 132 executes the machine-executable program 201, it implements the multi-connected air conditioner heating control method according to any one of the above embodiments.

[0146] Specifically, the controller 130 can include a processor 132 adapted to execute stored instructions and a memory 131 that provides temporary storage space for the operation of the instructions during operation. The processor 132 can be a single-core processor 132, a multi-core processor 132, a computing cluster, or any other number of other configurations. The memory 131 can include a random access memory 131 (RAM), a read-only memory 131, a flash memory, or any other suitable storage system.

[0147] The processor 132 may be connected via a system interconnect (such as PCI, PCI-Express, etc.) to an I / O interface (input / output interface) adapted to connect the multi-connected unit 100 to one or more I / O devices (input / output devices). The I / O devices may include, for example, a keyboard and a pointing device, where the pointing device may include a touchpad or a touch screen, etc.

[0148] The processor 132 may also be linked via a system interconnect to a display interface adapted to connect the controller 130 to a display device. The display device may include a display screen as a built-in component of the controller 130. The display device may also include a computer monitor, a television, a projector, etc. externally connected to the multi-connected unit 100. In addition, a network interface controller (NIC) may be adapted to connect the controller 130 to a network via a system interconnect. In some embodiments, the NIC may use any suitable interface or protocol (such as Internet Small Computer System Interface, etc.) to transmit data. The network may be a cellular network, a radio network, a wide area network (WAN), a local area network (LAN), or the Internet, etc. A remote device may be connected to the controller 130 via the network.

[0149] The flowchart provided in this embodiment is not intended to indicate that the operations of the method will be executed in any specific order, or that all operations of the method are included in every case. In addition, the method may include additional operations. Within the scope of the technical concept provided by the method in this embodiment, additional changes may be made to the above method.

[0150] There are multiple exemplary embodiments of the present invention. However, without departing from the spirit and scope of the present invention, many other variations or modifications that conform to the principles of the present invention can still be directly determined or derived from the content disclosed in the present invention. Therefore, the scope of the present invention should be understood and determined to cover all these other variations or modifications.

Claims

1. A multi-connected machine heat control method, characterized in that Including: Obtain the starting capacity of the indoor unit; In response to the compressor reaching the target operating frequency and lasting for a preset duration, obtain the actual exhaust temperature of the compressor, and compare the actual exhaust temperature with the threshold range of the exhaust temperature; If the actual exhaust temperature is within the threshold range, obtain the suction pressure of the compressor; Obtain the target suction superheat of the compressor according to the starting capacity and the suction pressure.

2. The multi-connected unit heating control method according to claim 1, wherein: Multiple preset suction pressure intervals, multiple preset starting capacity intervals, and multiple preset suction superheats are preset in the multi-connected unit; The obtaining of the target suction superheat according to the starting capacity and the suction pressure includes: Judge the preset suction pressure interval where the starting capacity is located and the preset starting capacity interval where the starting capacity is located, and use the preset suction superheat corresponding to the preset suction pressure interval and the preset starting capacity interval as the target suction superheat.

3. The multi-unit heat control method according to claim 1, characterized in that, It further includes: If the actual exhaust temperature is less than the lower limit value of the threshold range, use the first superheat value as the target suction superheat of the compressor; And / or If the actual exhaust temperature is greater than the upper limit value of the threshold range, use the second superheat value as the target suction superheat of the compressor; Wherein, the second superheat value is less than the first superheat value.

4. The multi-unit heat control method according to claim 1, characterized in that, It further includes: In response to obtaining the target suction superheat, obtain the actual suction superheat of the compressor; Control the opening degree of the main throttle valve according to the target suction superheat and the actual suction superheat.

5. The multi-connected unit heating control method according to claim 4, wherein: After controlling the opening degree of the main throttle valve according to the target suction superheat and the actual suction superheat, it further includes: Execute the step of obtaining the actual exhaust temperature of the compressor every first duration; and / or Execute the step of obtaining the starting capacity of the indoor unit every second duration.

6. The multi-connected unit heating control method according to claim 4, wherein: The obtaining of the actual suction superheat of the compressor includes: Obtain the suction pressure of the compressor; Obtain the saturated suction temperature at least according to the suction pressure; Obtain the temperature of the condenser outlet pipe; Calculate the difference between the saturated suction temperature and the temperature of the condenser outlet pipe to obtain the actual suction superheat; Wherein, the obtaining of the saturated suction temperature at least according to the suction pressure includes: Obtain the saturated suction temperature according to the suction pressure; or Obtain the pressure loss of the refrigerant from the gas separation outlet to the compressor inlet to obtain the suction pressure drop; Obtain the saturated suction temperature according to the suction pressure and the suction pressure drop.

7. The multi-connected unit heating control method according to claim 6, wherein: The calculation formula of the suction pressure drop is: Wherein, △P is the suction pressure drop; L is the pipeline length from the gas separation outlet to the compressor inlet; D is the inner diameter of the pipeline from the gas separation outlet to the compressor inlet.

8. The multi-unit heat control method according to claim 1, wherein It further includes: The outdoor unit receives the starting signal transmitted by the indoor unit; In response to the starting signal, execute the step of obtaining the starting capacity of the indoor unit; Obtain the set temperature of the started indoor unit and the outdoor ambient temperature; Obtain the target operating frequency of the compressor according to the startup capacity, the set temperature of the indoor unit that has been started, and the outdoor ambient temperature; Control the compressor to start and increase the frequency to the target operating frequency.

9. A machine-readable storage medium, characterized in that, A machine-executable program is stored thereon, and when the machine-executable program is executed by a processor, it implements the multi-connected unit heating control method according to any one of claims 1 to 8.

10. A multi-connected air conditioner, characterized in that, It includes a controller, the controller includes a memory, a processor, and a machine-executable program stored on the memory and running on the processor, and when the processor executes the machine-executable program, it implements the multi-connected unit heating control method according to any one of claims 1 to 8.

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