Control method and operation control device for rotating speed of outer fan of multi-split air conditioner and multi-split air conditioner

Abstract

The invention discloses a control method and an operation control device for the rotating speed of an outer fan of a multi-split air conditioner, the multi-split air conditioner and a computer readable storage medium, and the control method comprises the steps that in the compressor starting stage, the target frequency of a compressor and the outdoor environment temperature are obtained, and the rotating speed of the outer fan is determined according to the target frequency of the compressor and the outdoor environment temperature; in the refrigeration operation stage, the middle temperature of an outdoor heat exchanger and the first refrigerant temperature are obtained, and the rotating speed of an outer fan is determined according to the middle temperature of the outdoor heat exchanger and the first refrigerant temperature; wherein when the running duration after the compressor is started does not exceed the first preset duration, the multi-split air conditioner is in the compressor starting stage; when the operation duration after the compressor is started exceeds a first preset duration and the compressor operates in a refrigeration mode, the multi-split air conditioner is in a refrigeration operation stage; the first refrigerant temperature is the refrigerant temperature conveyed to the main control board of the outdoor unit for heat dissipation. The control precision of the rotating speed of the outer fan can be improved, the heat exchange effect is improved, and the system efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioning, and in particular to a method for controlling the speed of an external fan of a multi-split unit, an operation control device, a multi-split unit and a computer-readable storage medium. Background Art

[0002] With the guidance of national energy conservation and emission reduction policies and the change of user consumption concepts, the application proportion of household multi-split units in the field of household air conditioning is increasing, so the control of multi-split systems is becoming increasingly important. Among them, the control of the external fan in the multi-split system mainly involves speed control.

[0003] At present, the speed control accuracy of most multi-split external fans is not high enough, which leads to the inability to better match the heat exchange requirements of the multi-split system, affecting the heat exchange effect and system efficiency. Summary of the invention

[0004] The purpose of the present invention is to solve at least one of the technical problems existing in the prior art, and to provide a method for controlling the speed of an external fan of a multi-split unit, an operation control device, a multi-split unit and a computer-readable storage medium, which can improve the control accuracy of the speed of the external fan, enhance the heat exchange effect and improve the system efficiency.

[0005] In a first aspect, an embodiment of the present invention provides a method for controlling the speed of an external fan of a multi-split system, comprising:

[0006] During the compressor startup phase, the compressor target frequency and the outdoor ambient temperature are obtained, and the external fan speed is determined according to the compressor target frequency and the outdoor ambient temperature;

[0007] In the cooling operation stage, the middle temperature of the outdoor heat exchanger and the first refrigerant temperature are obtained, and the speed of the outdoor fan is determined according to the middle temperature of the outdoor heat exchanger and the first refrigerant temperature;

[0008] Among them, when the running time of the compressor after starting does not exceed the first preset time, the multi-split machine is in the compressor starting stage; when the running time of the compressor after starting exceeds the first preset time and runs in the cooling mode, the multi-split machine is in the cooling operation stage; the first refrigerant temperature is the refrigerant temperature transported to the external unit main control board for heat dissipation.

[0009] The method for controlling the external fan speed of a multi-split unit provided in accordance with an embodiment of the present invention has at least the following beneficial effects: in the startup phase of the compressor, the external fan speed is adjusted based on both the outdoor ambient temperature and the target frequency of the compressor, so that the startup speed of the external fan can better match the heat exchange demand of the outdoor unit. Compared with the control strategy of calculating the external fan speed only according to the outdoor ambient temperature, it can avoid the waste of power consumption caused by the external fan speed being too high when the compressor is started at a low target frequency, and avoid the failure to meet the heat exchange demand caused by the external fan speed being too low when the compressor is started at a high target frequency. When the operating time after the compressor is started exceeds the first preset time, the multi-split unit exits the compressor startup phase. If the multi-split unit is running in the cooling mode at this time, the multi-split unit enters the cooling operation phase. At this time, the external fan speed is corrected jointly according to the first refrigerant temperature and the middle temperature of the outdoor heat exchanger, so that the determination of the external fan speed fully considers the heat exchange demand, thereby more accurately maintaining it within a reasonable range, which can improve the control accuracy of the external fan speed, improve the heat exchange effect and improve the system efficiency.

[0010] According to the control method provided in some embodiments of the present invention, the determining of the speed of the outdoor fan according to the middle temperature of the outdoor heat exchanger and the first refrigerant temperature includes:

[0011] The speed gear of the outdoor fan is determined according to the maximum value of the middle temperature of the outdoor heat exchanger and the first refrigerant temperature and the change of the maximum value.

[0012] According to the control method provided by some embodiments of the present invention, when the maximum value is greater than a first preset temperature, or when the maximum value is greater than a second preset temperature and the change in the maximum value is greater than zero, the speed gear is increased by one gear;

[0013] Wherein, the first preset temperature is greater than the second preset temperature.

[0014] According to the control method provided by some embodiments of the present invention, when the maximum value is less than a fourth preset temperature, or when the maximum value is less than a third preset temperature and the change in the maximum value is less than zero, the speed gear is reduced by one gear;

[0015] The second preset temperature is greater than the third preset temperature, and the third preset temperature is greater than the fourth preset temperature.

[0016] According to the control method provided by some embodiments of the present invention, when the maximum value is greater than the second preset temperature and the change of the maximum value is less than zero, or when the maximum value is less than the third preset temperature and the change of the maximum value is greater than zero, the speed gear remains unchanged.

[0017] According to the control method provided by some embodiments of the present invention, when the maximum value is greater than a fifth preset temperature, the speed gear is increased to a highest gear; wherein the fifth preset temperature is greater than the first preset temperature.

[0018] According to the control method provided by some embodiments of the present invention, the determining of the speed of the outdoor fan according to the compressor target frequency and the outdoor ambient temperature includes:

[0019] Divide a plurality of temperature intervals between a preset temperature upper limit value and a preset temperature lower limit value, and divide a plurality of frequency intervals between a preset frequency upper limit value and a preset frequency lower limit value;

[0020] Determine the rotation speed of the external fan according to the temperature interval within which the outdoor ambient temperature falls and the frequency interval within which the compressor target frequency falls;

[0021] Among them, the higher the outdoor ambient temperature, the greater the speed of the external fan; the higher the compressor target frequency, the greater the speed of the external fan.

[0022] According to the control method provided by some embodiments of the present invention, during the compressor startup phase, when the outdoor heat exchanger temperature is greater than a sixth preset temperature and the running time after the compressor is started exceeds a second preset time, the compressor startup phase is exited.

[0023] According to the control method provided in some embodiments of the present invention, when the outdoor ambient temperature is greater than the seventh preset temperature, the speed gear of the outdoor fan is increased to the highest gear; when the outdoor ambient temperature is lower than the eighth preset temperature, the speed gear of the outdoor fan is reduced to the lowest gear, and the seventh preset temperature is greater than the eighth preset temperature.

[0024] According to the control method provided by some embodiments of the present invention, when the compressor exhaust temperature is greater than a ninth preset temperature, the speed gear of the external fan is increased to a highest gear.

[0025] In a second aspect, an embodiment of the present invention provides an operation control device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the control method as described in the embodiment of the first aspect above.

[0026] In a third aspect, an embodiment of the present invention provides a multi-split system, comprising an operation control device as described in the embodiment of the second aspect above.

[0027] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores computer-executable instructions, and the computer-executable instructions are used to enable a computer to execute the control method described in the embodiment of the first aspect above.

[0028] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings are used to provide a further understanding of the technical solution of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the technical solution of the present invention and do not constitute a limitation on the technical solution of the present invention.

[0030] The present invention is further described below in conjunction with the accompanying drawings and embodiments;

[0031] Figure 1 is a flow chart of a method for controlling the speed of an external fan of a multi-split system provided by an embodiment of the present invention;

[0032] Figure 2 yes Figure 1 A detailed flowchart of step S110 in FIG.

[0033] Figure 3 It is a flow chart of a method for controlling the speed of an external fan of a multi-split system provided by a specific embodiment of the present invention;

[0034] Figure 4 It is a structural schematic diagram of the operation control device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0035] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it cannot be understood as a limitation on the scope of protection of the present invention.

[0036] In the description of the embodiments of the present invention, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed", etc. are understood to exclude the number itself, "above", "below", "within", etc. are understood to include the number itself, "at least one" means one or more, "at least one of the following" and similar expressions refer to any combination of these items, including any combination of single or plural items. If there is a description of "first", "second", etc., it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0037] It should be noted that the terms such as setting, installing, and connecting in the embodiments of the present invention should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above terms in the embodiments of the present invention in combination with the specific content of the technical solution. For example, the term "connection" can be a mechanical connection, an electrical connection, or mutual communication; it can be directly connected or indirectly connected through an intermediate medium.

[0038] It should be noted that the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0039] With the guidance of the national energy conservation and emission reduction policy and the change of user consumption concepts, the application proportion of household multi-split units in the field of household air conditioning is increasing, so the control of multi-split systems has become increasingly important. Among them, the control of the external fan in the multi-split system mainly involves speed control. At present, the speed control accuracy of most multi-split external fans is not high enough, resulting in the inability to match the heat exchange requirements of the multi-split system well, affecting the heat exchange effect and system efficiency.

[0040] Based on this, an embodiment of the present invention provides a method for controlling the speed of an external fan of a multi-split system, an operation control device, a multi-split system and a computer-readable storage medium, which can improve the control accuracy of the speed of the external fan and improve the system efficiency.

[0041] The embodiments of the present invention are further described below in conjunction with the accompanying drawings.

[0042] Reference Figure 1 The first aspect of the present invention provides a method for controlling the speed of an external fan of a multi-split system, including but not limited to steps S110 to S120:

[0043] Step S110: in the compressor startup phase, the compressor target frequency FanIniFr and the outdoor ambient temperature T4 are obtained, and the external fan speed is determined according to the compressor target frequency FanIniFr and the outdoor ambient temperature T4;

[0044] Step S120: in the cooling operation stage, obtaining the middle temperature T3B of the outdoor heat exchanger and the first refrigerant temperature T5, and determining the speed of the outdoor fan according to the middle temperature T3B of the outdoor heat exchanger and the first refrigerant temperature T5;

[0045] It can be understood that step S110 and step S120 respectively adopt different control strategies for the speed of the external fan of the multi-split system in different operation stages.

[0046] Among them, when the running time after the compressor is started does not exceed the first preset time Tim1, the multi-split system is in the compressor starting stage; when the running time after the compressor is started exceeds the first preset time Tim1 and runs in the cooling mode, the multi-split system is in the cooling operation stage; the first refrigerant temperature T5 is the refrigerant temperature transported to the external unit main control board for heat dissipation.

[0047] It is understandable that the multi-split unit includes at least one outdoor unit and multiple indoor units, wherein the outdoor unit includes a compressor, a four-way valve, an outdoor heat exchanger, an outdoor fan, etc. The four-way valve is respectively connected to the exhaust port of the compressor, the outdoor heat exchanger, and the air intake port of the compressor. The outdoor heat exchanger is also connected to one end of the indoor heat exchanger of multiple indoor units through a refrigerant gas pipe, and the four-way valve is also connected to the other end of the indoor heat exchanger of multiple indoor units through a refrigerant liquid pipe. It should be noted that the outdoor unit is also provided with an outdoor unit main control board, which is used to power the compressor, the outdoor fan, and some solenoid valves and sensors in the outdoor unit. The outdoor unit main control board will generate a lot of heat during operation, so generally a refrigerant pipeline will be drawn out from the outdoor heat exchanger to transport the low-temperature refrigerant to the outdoor unit main control board for heat dissipation. The first refrigerant temperature T5 can be measured by setting a temperature sensor in the refrigerant pipeline. The temperature sensor can be set at the inlet, middle position or outlet of the refrigerant pipeline, and this application does not limit this.

[0048] According to the control method of the external fan speed of a multi-split unit provided in an embodiment of the present invention, in the compressor startup phase, the external fan speed is adjusted based on both the outdoor ambient temperature T4 and the compressor target frequency FanIniFr, so that the startup speed of the external fan can better match the heat exchange demand of the outdoor unit. Compared with the control strategy of calculating the external fan speed only based on the outdoor ambient temperature T4, it can avoid the power consumption waste caused by the external fan speed being too high when the compressor is started at a low target frequency, and avoid the situation where the heat exchange demand cannot be met due to the external fan speed being too low when the compressor is started at a high target frequency. When the operating time after the compressor is started exceeds the first preset time Tim1, the multi-split unit exits the compressor startup phase. If the multi-split unit is running in the cooling mode at this time, the multi-split unit enters the cooling operation phase. At this time, the external fan speed is jointly corrected according to the first refrigerant temperature T5 and the middle temperature T3B of the outdoor heat exchanger, so that the determination of the external fan speed fully considers the heat exchange demand, thereby more accurately maintaining it within a reasonable range, which can improve the control accuracy of the external fan speed, improve the heat exchange effect and improve the system efficiency.

[0049] Reference Figure 2 In the control method provided in some embodiments of the present invention, the step S110 of determining the speed of the outdoor fan according to the compressor target frequency FanIniFr and the outdoor ambient temperature T4 includes but is not limited to steps S210 to S220:

[0050] Step S210: dividing a plurality of temperature intervals between a preset temperature upper limit value and a preset temperature lower limit value, and dividing a plurality of frequency intervals between a preset frequency upper limit value and a preset frequency lower limit value;

[0051] Step S220: determining the speed of the external fan according to the temperature interval into which the outdoor ambient temperature T4 falls and the frequency interval into which the compressor target frequency FanIniFr falls;

[0052] Among them, the higher the outdoor ambient temperature T4, the greater the speed of the outdoor fan; the higher the compressor target frequency FanIniFr, the greater the speed of the outdoor fan.

[0053] Refer to Table 1, which is a reference table for determining the speed of the external fan of the multi-split unit during the compressor startup phase, wherein the first row illustrates the division of each frequency interval, and the first column illustrates the division of each temperature interval. It can be seen that the preset temperature upper limit value in step S210 is set to 60°C, the preset temperature lower limit value is set to -20°C, and then multiple temperature points such as -10°C, -5°C, 0°C, 10°C, 19°C, 22°C, 25°C, 28°C, 33°C, 38°C, and 45°C are selected between -20°C and 60°C, so that a temperature interval is formed between two adjacent temperature points. It can be understood that, using the division method shown in Table 1, the boundary values ​​of two adjacent temperature intervals are the same, that is, multiple temperature intervals are continuous; a discontinuous temperature interval division method can also be used, for example, 0°C to 5°C is a temperature interval, and the next temperature interval is 10°C to 15°C. Similarly, it can be seen that the preset frequency upper limit value in step S210 is set to F25, the preset frequency lower limit value is set to 0, and then multiple frequency points such as FanIniFr1, FanIniFr2, FanIniFr3 are selected between 0 and F25, where FanIniFr1<FanIniFr2<FanIniFr3, so that a frequency interval is formed between two adjacent frequency points. It can also be understood that, using the division method shown in Table 1, the boundary values ​​of two adjacent frequency intervals are the same, that is, multiple frequency intervals are continuous; a discontinuous frequency interval division method can also be used, for example, 0 to FanIniFr1 is a frequency interval, and the next frequency interval is FanIniFr2 to FanIniFr3.

[0054] Table 1 Reference table for determining the speed of the external fan

[0055]

[0056]

[0057] In addition, A++, A+, A, B, C, D, E, F, G, H, J, K, L, M, and N in Table 1 represent different speeds, and the speeds decrease in sequence. It can be understood that the higher the compressor target frequency FanIniFr, the greater the heat exchange demand, so the speed of the external fan is controlled to be higher to improve the heat exchange effect and match the higher heat exchange demand; the higher the outdoor ambient temperature T4, the worse the heat exchange effect of the outdoor heat exchanger, so it is also necessary to control the speed of the external fan to be higher to improve the heat exchange effect.

[0058] In the control method provided in some embodiments of the present invention, the step S120 of determining the speed of the outdoor fan according to the middle temperature T3B of the outdoor heat exchanger and the first refrigerant temperature T5 includes:

[0059] The speed gear of the outdoor fan is determined according to the maximum value Max(T3B, T5) of the middle temperature T3B of the outdoor heat exchanger and the first refrigerant temperature T5 and the change ΔMax(T3B, T5) of the maximum value.

[0060] It can be understood that the maximum value Max(T3B, T5) between the middle temperature T3B of the outdoor heat exchanger and the first refrigerant temperature T5 can more accurately reflect the maximum heat exchange demand of the outdoor unit, and the change in the maximum value ΔMax(T3B, T5) can reflect the changing trend of the maximum heat exchange demand of the outdoor unit. Therefore, in this embodiment, the speed gear of the outdoor fan is determined according to the maximum value Max(T3B, T5) and the change in the maximum value ΔMax(T3B, T5), so that the speed of the outdoor fan can match the maximum heat exchange demand of the outdoor unit and conform to the changing trend of the maximum heat exchange demand.

[0061] In the control method provided in some embodiments of the present invention, when the maximum value Max(T3B, T5) is greater than the first preset temperature T3BSuperOn, or when the maximum value Max(T3B, T5) is greater than the second preset temperature T3BOn and the change in the maximum value ΔMax(T3B, T5) is greater than zero, the speed gear is increased by one gear;

[0062] The first preset temperature T3BSuperOn is greater than the second preset temperature T3BOn.

[0063] It should be noted that when the maximum value Max(T3B, T5) of the middle temperature T3B of the outdoor heat exchanger and the first refrigerant temperature T5 is greater than the second preset temperature T3BOn and the change in the maximum value ΔMax(T3B, T5) is greater than zero, it means that the maximum heat exchange demand of the outdoor unit is large and is still rising, so it is necessary to increase the speed gear to improve the heat exchange effect of the outdoor heat exchanger; and when the maximum value Max(T3B, T5) of the middle temperature T3B of the outdoor heat exchanger and the first refrigerant temperature T5 is greater than the first preset temperature T3BSuperOn, it means that the maximum heat exchange demand of the outdoor unit is very large. At this time, there is no need to consider the changing trend of the maximum heat exchange demand, and the speed gear can be directly increased to improve the heat exchange effect of the outdoor heat exchanger.

[0064] In the control method provided by some embodiments of the present invention, when the maximum value Max(T3B, T5) is less than the fourth preset temperature T3BSuperDown, or when the maximum value Max(T3B, T5) is less than the third preset temperature T3BDown and the change in the maximum value ΔMax(T3B, T5) is less than zero, the speed gear is reduced by one gear;

[0065] The second preset temperature T3BOn is greater than the third preset temperature T3BDown, and the third preset temperature T3BDown is greater than the fourth preset temperature T3BSuperDown.

[0066] It should be noted that when the maximum value Max(T3B, T5) of the middle temperature T3B of the outdoor heat exchanger and the first refrigerant temperature T5 is less than the third preset temperature T3BDown and the change in the maximum value ΔMax(T3B, T5) is less than zero, it means that the maximum heat exchange demand of the outdoor unit is small and is still decreasing, so it is necessary to reduce the speed gear, thereby reducing the heat exchange effect of the outdoor heat exchanger; and when the maximum value Max(T3B, T5) of the middle temperature T3B of the outdoor heat exchanger and the first refrigerant temperature T5 is less than the fourth preset temperature T3BSuperDown, it means that the maximum heat exchange demand of the outdoor unit is very small. At this time, there is no need to consider the changing trend of the maximum heat exchange demand. The speed gear can be directly reduced to reduce the heat exchange effect of the outdoor heat exchanger, thereby avoiding energy waste.

[0067] In the control method provided in some embodiments of the present invention, when the maximum value Max(T3B, T5) is greater than the second preset temperature T3BOn and the change in the maximum value ΔMax(T3B, T5) is less than zero, or when the maximum value Max(T3B, T5) is less than the third preset temperature T3BDown and the change in the maximum value ΔMax(T3B, T5) is greater than zero, the speed gear remains unchanged.

[0068] It should be noted that when the maximum value Max(T3B, T5) of the middle temperature T3B of the outdoor heat exchanger and the first refrigerant temperature T5 is greater than the second preset temperature T3BOn and the change in the maximum value ΔMax(T3B, T5) is less than zero, it means that the maximum heat exchange demand of the outdoor unit is large but on a downward trend, and the speed gear can adapt to the change in heat exchange demand, so there is no need to adjust the speed gear; similarly, when the maximum value Max(T3B, T5) of the middle temperature T3B of the outdoor heat exchanger and the first refrigerant temperature T5 is less than the third preset temperature T3BDown and the change in the maximum value ΔMax(T3B, T5) is greater than zero, it means that the maximum heat exchange demand of the outdoor unit is small but on an upward trend, and the speed gear can adapt to the change in heat exchange demand, so there is no need to adjust the speed gear.

[0069] In the control method provided in some embodiments of the present invention, when the maximum value Max(T3B, T5) is greater than the fifth preset temperature T3T5Max°C, the speed gear is increased to the highest gear; wherein the fifth preset temperature T3T5Max°C is greater than the first preset temperature T3BSuperOn.

[0070] It is understandable that the fifth preset temperature T3T5Max℃ is greater than the first preset temperature T3BSuperOn, that is, as a larger temperature limit value, when the maximum value Max(T3B, T5) is greater than the fifth preset temperature T3T5Max℃, it indicates that the heat exchange demand is very large. At this time, if the speed gear of the outdoor fan is adjusted one by one, it will be slow. Directly increasing the speed gear to the highest gear can quickly increase the heat exchange effect of the outdoor heat exchanger to the maximum. At this time, the middle temperature T3B of the outdoor heat exchanger and the first refrigerant temperature T5 are continuously detected until the maximum value Max(T3B, T5) of the middle temperature T3B of the outdoor heat exchanger and the first refrigerant temperature T5 is less than the fifth preset temperature T3T5Max℃-5℃, and the speed gear is exited to maintain the highest gear control.

[0071] In the control method provided in some embodiments of the present invention, during the compressor startup phase, when the outdoor heat exchanger temperature T3 is greater than the sixth preset temperature and the compressor operation time after startup exceeds the second preset time, the compressor startup phase is exited, wherein the second preset time is less than the first preset time Tim1. Exemplarily, the first preset time Tim1 is set to 60s, the second preset time is set to 20s, and the sixth preset temperature is set to 57°C.

[0072] It can be understood that when the outdoor heat exchanger temperature T3 is greater than the sixth preset temperature 57°C, it means that the outdoor heat exchanger temperature T3 has been raised to a sufficiently high level. At this time, there is no need to wait until the operating time after the compressor is started exceeds the first preset time Tim1, as long as it exceeds the second preset time 20s. That is, when the outdoor heat exchanger temperature T3 is high, the compressor start-up stage can be exited in advance, and then the refrigeration operation stage is entered. The control strategy of the refrigeration operation stage is used to regulate the external fan speed, so that the control accuracy of the external fan speed is higher.

[0073] In the control method provided in some embodiments of the present invention, when the outdoor ambient temperature T4 is greater than the seventh preset temperature, the speed gear of the outdoor fan is increased to the highest gear; when the outdoor ambient temperature T4 is lower than the eighth preset temperature, the speed gear of the outdoor fan is reduced to the lowest gear, and the seventh preset temperature is greater than the eighth preset temperature.

[0074] It can be understood that, in this embodiment, the seventh preset temperature and the eighth preset temperature correspond to the critical values ​​of the two extreme conditions of the outdoor ambient temperature T4, for example, the seventh preset temperature can be set to 45°C, and the eighth preset temperature can be set to 5°C, that is, when the outdoor ambient temperature T4 is greater than the high temperature critical value of 45°C, the speed gear of the outdoor fan is directly controlled to be increased to the highest gear, thereby improving the heat exchange effect of the outdoor heat exchanger and avoiding insufficient heat exchange effect when the outdoor ambient temperature is high; similarly, when the outdoor ambient temperature T4 is less than the low temperature critical value of 5°C, the speed gear of the outdoor fan is directly controlled to drop to the lowest gear, avoiding excessive heat exchange effect when the outdoor ambient temperature is low. It can be understood that the lowest gear of the speed gear can be set to the shutdown gear, that is, when the outdoor ambient temperature is low, there is no need to turn on the outdoor fan. In addition, when the speed gear of the outdoor fan is in the promotion stage, it can only be increased to the highest gear at most; when the speed gear of the outdoor fan is in the decline stage, it can only be reduced to the lowest gear at least.

[0075] In addition, when the speed gear of the outdoor fan is at the lowest gear, that is, at the shutdown gear, the maximum value Max(T3B, T5) of the middle temperature T3B of the outdoor heat exchanger and the first refrigerant temperature T5 can be redetected and updated every third preset time period. When the maximum value Max(T3B, T5) of the middle temperature T3B of the outdoor heat exchanger and the first refrigerant temperature T5 meets the gear-up condition or the gear-keeping condition, the outdoor fan is immediately turned on according to the lowest gear at which the outdoor fan can operate.

[0076] In the control method provided in some embodiments of the present invention, when the compressor exhaust temperature is greater than a ninth preset temperature, the speed gear of the external fan is increased to the highest gear. Exemplarily, the ninth preset temperature can be set to 95°C.

[0077] It is understandable that when the compressor exhaust temperature is greater than the ninth preset temperature of 95°C, it means that the heat exchange demand is large. At this time, if the speed of the external fan is adjusted one gear at a time, it will be slow. Directly increasing the speed gear to the highest gear can quickly increase the heat exchange effect of the outdoor heat exchanger to the maximum, thereby quickly matching the heat exchange needs of the multi-split system and improving system efficiency.

[0078] In order to more clearly explain the method for controlling the speed of the external fan of the multi-split system of the present invention, Figure 3 , a comprehensive and detailed introduction is given with a specific embodiment.

[0079] The method for controlling the speed of the external fan of a multi-split system comprises the following steps:

[0080] Step S301: start the compressor cooling; jump to step S302 for execution;

[0081] Step S302: Determine the speed of the outdoor fan according to the compressor target frequency FanIniFr and the outdoor ambient temperature T4; jump to step S303 for execution;

[0082] Step S303: Execute the external fan speed; jump to step S304 for execution;

[0083] Step S304: Determine whether the running time of the compressor after the refrigeration is started is greater than the first preset time Tim1? If yes, jump to step S305 for execution; if not, jump back to step S303;

[0084] Step S305: Determine whether the compressor exhaust temperature is greater than 95°C. If yes, jump to step S306; if no, jump to step S307 for execution;

[0085] Step S306: the speed gear is the highest gear; jump back to step S303;

[0086] Step S307: Determine whether the maximum value Max(T3B, T5) of the middle temperature T3B of the outdoor heat exchanger and the first refrigerant temperature T5 is greater than or equal to the second preset temperature T3BOn and less than or equal to the first preset temperature T3BSuperOn? If yes, jump to step S308 for execution; if not, jump to step S312 for execution;

[0087] Step S308: Determine whether the maximum value change ΔMax(T3B, T5) is greater than 0. If yes, jump to step S309 for execution; if not, jump to step S311 for execution;

[0088] Step S309: After the timing Tim2 seconds, the speed gear is increased by one gear; jump to step S310 for execution;

[0089] Step S310: Determine whether the speed gear reaches the highest gear. If yes, jump to step S306; if no, jump back to step S303;

[0090] Step S311: the speed gear remains unchanged; jump back to step S303;

[0091] Step S312: Determine whether the maximum value Max(T3B, T5) of the middle temperature T3B of the outdoor heat exchanger and the first refrigerant temperature T5 is greater than the first preset temperature T3BSuperOn? If yes, jump to step S309 for execution; if not, jump to step S313 for execution;

[0092] Step S313: Determine whether the maximum value Max(T3B, T5) of the middle temperature T3B of the outdoor heat exchanger and the first refrigerant temperature T5 is greater than or equal to the fourth preset temperature T3BSuperDown and less than or equal to the third preset temperature T3BDown? If yes, jump to step S314 for execution; if not, jump to step S318 for execution;

[0093] Step S314: Determine whether the maximum value change ΔMax(T3B, T5) is less than 0. If yes, jump to step S315 for execution; if not, jump to step S311 for execution;

[0094] Step S315: After the timing Tim2 seconds, the speed gear is reduced by one gear; jump to step S316 for execution;

[0095] Step S316: Determine whether the speed gear reaches the lowest gear. If yes, jump to step S317; if no, jump back to step S303;

[0096] Step S317: the speed gear is the lowest gear; jump back to step S303;

[0097] Step S318: Determine whether the maximum value Max(T3B, T5) of the middle temperature T3B of the outdoor heat exchanger and the first refrigerant temperature T5 is less than the fourth preset temperature T3BSuperDown. If yes, jump to step S315 for execution; otherwise, jump to step S311 for execution.

[0098] By adopting Figure 3The control method of the external fan speed of the multi-split unit shown in the figure, during the compressor startup phase, adjusts the external fan speed based on both the outdoor ambient temperature T4 and the compressor target frequency FanIniFr, so that the startup speed of the external fan can better match the heat exchange demand of the outdoor unit. Compared with the control strategy of calculating the external fan speed only based on the outdoor ambient temperature T4, it can avoid the power consumption waste caused by the external fan speed being too high when the compressor is started at a low target frequency, and avoid the situation where the external fan speed is too low when the compressor is started at a high target frequency and cannot meet the heat exchange demand; when the operating time after the compressor is started exceeds the first preset time Tim1, the multi-split unit exits the compressor startup phase. If the multi-split unit is running in the cooling mode at this time, the multi-split unit enters the cooling operation phase. At this time, the external fan speed is jointly corrected according to the first refrigerant temperature T5 and the middle temperature T3B of the outdoor heat exchanger, so that the determination of the external fan speed fully considers the heat exchange demand, thereby more accurately maintaining it within a reasonable range, which can improve the control accuracy of the external fan speed, improve the heat exchange effect and improve the system efficiency.

[0099] Reference Figure 4 The second aspect of the present invention provides an operation control device 400, including a memory 410, a processor 420, and a computer program stored in the memory 410 and executable on the processor 420. The processor 420 executes the program to implement the control method of the first aspect of the present invention, for example, to execute Figure 1 Steps S110 to S120 of the method, Figure 2 Steps S210 to S220 of the method or execution Figure 3 Method steps S301 to S318.

[0100] In addition, a third aspect of the present invention provides a multi-split system, including the operation control device 400 of the second aspect of the present invention.

[0101] In addition, a fourth aspect of the present invention provides a computer-readable storage medium, the computer-readable storage medium stores computer-executable instructions, and the computer-executable instructions are used to enable a computer to execute the control method of the first aspect of the present invention, such as executing Figure 1 Steps S110 to S120 of the method, Figure 2 Steps S210 to S220 of the method or execution Figure 3 Method steps S301 to S318.

[0102] It will be appreciated by those skilled in the art that all or some of the steps and systems in the disclosed methods above may be implemented as software, firmware, hardware and appropriate combinations thereof. Some physical components or all physical components may be implemented as software executed by a processor, such as a central processing unit, a digital signal processor or a microprocessor, or implemented as hardware, or implemented as an integrated circuit, such as an application specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include a computer storage medium or a non-transitory medium and a communication medium or a temporary medium. As known to those skilled in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information such as computer-readable instructions, data structures, program modules or other data. Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disk DVD or other optical disk storage, magnetic cassettes, magnetic tapes, disk storage or other magnetic storage devices, or any other medium that may be used to store desired information and may be accessed by a computer. Furthermore, it is well known to those skilled in the art that communication media typically embodies computer readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

[0103] The embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the knowledge scope of ordinary technicians in the technical field without departing from the purpose of the present invention.

Claims

1. A method for controlling the speed of an external fan of a multi-split system, characterized in that: include: During the compressor startup phase, the compressor target frequency and the outdoor ambient temperature are obtained, and the external fan speed is determined according to the compressor target frequency and the outdoor ambient temperature; In the cooling operation stage, the middle temperature of the outdoor heat exchanger and the first refrigerant temperature are obtained, and the speed of the outdoor fan is determined according to the middle temperature of the outdoor heat exchanger and the first refrigerant temperature; Among them, when the running time of the compressor after starting does not exceed the first preset time, the multi-split machine is in the compressor starting stage; when the running time of the compressor after starting exceeds the first preset time and runs in the cooling mode, the multi-split machine is in the cooling operation stage; the first refrigerant temperature is the refrigerant temperature transported to the external unit main control board for heat dissipation.

2. The control method according to claim 1, characterized in that: The step of determining the rotation speed of the outdoor fan according to the middle temperature of the outdoor heat exchanger and the first refrigerant temperature includes: The speed gear of the outdoor fan is determined according to the maximum value of the middle temperature of the outdoor heat exchanger and the first refrigerant temperature and the change of the maximum value.

3. The control method according to claim 2, characterized in that: When the maximum value is greater than the first preset temperature, or when the maximum value is greater than the second preset temperature and the change in the maximum value is greater than zero, the speed gear is increased by one gear; Wherein, the first preset temperature is greater than the second preset temperature.

4. The control method according to claim 3, characterized in that: When the maximum value is less than a fourth preset temperature, or when the maximum value is less than the third preset temperature and the change in the maximum value is less than zero, the speed gear is reduced by one gear; The second preset temperature is greater than the third preset temperature, and the third preset temperature is greater than the fourth preset temperature.

5. The control method according to claim 4, characterized in that: When the maximum value is greater than the second preset temperature and the change in the maximum value is less than zero, or when the maximum value is less than the third preset temperature and the change in the maximum value is greater than zero, the speed gear remains unchanged.

6. The control method according to claim 3, characterized in that: When the maximum value is greater than a fifth preset temperature, the speed gear is increased to a highest gear; wherein the fifth preset temperature is greater than the first preset temperature.

7. The control method according to claim 1, characterized in that: The step of determining the rotation speed of the outdoor fan according to the compressor target frequency and the outdoor ambient temperature includes: Divide a plurality of temperature intervals between a preset temperature upper limit value and a preset temperature lower limit value, and divide a plurality of frequency intervals between a preset frequency upper limit value and a preset frequency lower limit value; Determine the rotation speed of the external fan according to the temperature interval within which the outdoor ambient temperature falls and the frequency interval within which the compressor target frequency falls; Among them, the higher the outdoor ambient temperature, the greater the speed of the external fan; the higher the compressor target frequency, the greater the speed of the external fan.

8. The control method according to claim 1, characterized in that: In the compressor startup phase, when the outdoor heat exchanger temperature is greater than a sixth preset temperature and the compressor operation time after startup exceeds a second preset time, the compressor startup phase is exited.

9. The control method according to claim 1, characterized in that: When the outdoor ambient temperature is greater than the seventh preset temperature, the speed gear of the outdoor fan is increased to the highest gear; when the outdoor ambient temperature is less than the eighth preset temperature, the speed gear of the outdoor fan is reduced to the lowest gear, and the seventh preset temperature is greater than the eighth preset temperature.

10. The control method according to claim 1, characterized in that: When the compressor exhaust temperature is greater than the ninth preset temperature, the speed gear of the external fan is increased to the highest gear.

11. An operation control device, characterized in that: The invention comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the control method according to any one of claims 1 to 10.

12. A multi-link system, characterized in that: Includes the operation control device as claimed in claim 11.

13. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer-executable instructions, and the computer-executable instructions are used to enable a computer to execute the control method according to any one of claims 1 to 10.

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