Multi-connected unit heat control method, multi-connected unit and storage medium

Abstract

The present invention discloses a heating control method for a multi-connected unit, a multi-connected unit and a storage medium. The heating control method for the multi-connected unit includes: after the multi-connected unit enters the heating operation, calculating the heating load of the multi-connected unit and detecting the available outdoor units that can operate currently; if the sum of the capacities of each available outdoor unit with the same capacity is greater than the heating load / β1, selecting the number of units to be started from the available outdoor units with the lowest capacity that meet the requirements; if the sum of the capacities of at least one type of available outdoor unit with the same capacity is between the heating load / β2 and the heating load / β1, starting all the available outdoor units with the lowest capacity that meet the requirements; if the sum of the capacities of each available outdoor unit with the same capacity is less than the heating load / β2, selecting the number of units to be started from the available outdoor units that meet the requirements in ascending order of capacity. The present invention improves the operation stability of the multi-connected unit by reasonably distributing the heating load and preventing a single outdoor unit from overoperating.

Description

Technical Field

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

[0002] At present, most multi-connected air conditioners on the market are modular multi-connected air conditioners, that is, multiple outdoor units are installed in parallel. Although this installation method greatly reduces the labor and space costs of air conditioner installation, since in many cases, it is a combination of large and small modules installed, the outdoor units are not all of the same capacity, or due to the influence of the installation environment, there is refrigerant uneven flow among the multi-connected air conditioners, and the refrigerant uneven flow affects the performance and reliability of the unit. Therefore, there is still a large room for improvement in the operation stability of traditional multi-connected air conditioners.

[0003] Especially during heating operation, most of the existing control schemes for multi-connected air conditioners do not consider the influence brought by uneven flow, and only simply allocate the heating load according to the ratio of the rated capacity of the outdoor units. However, the refrigerant uneven flow will cause too large a low-pressure difference between different outdoor units, and it is easy to frequently trigger the multi-connected air conditioner to enter the defrosting state. Specifically, the high pressure of each outdoor unit is the same, so the amount of refrigerant distributed to each outdoor unit is almost the same. However, for outdoor units of different capacities under the same load ratio, the suction air volume is inconsistent, while the amount of refrigerant distributed is almost the same, which leads to a lower low-pressure value for the outdoor unit with a larger suction air volume. In winter, the outdoor unit with a lower low-pressure value is more likely to frost, and the conventional heat pump multi-connected air conditioner cannot operate in defrosting and heating simultaneously. Therefore, during high-load heating operation, due to the low low-pressure value and easy frosting of some outdoor units, the entire multi-connected air conditioner frequently enters the defrosting state, seriously affecting the user experience. Moreover, defrosting requires the compressor to operate at a high frequency, resulting in energy waste and increasing the energy consumption of the multi-connected air conditioner. Summary of the Invention

[0004] In order to solve the defect that the existing multi-connected air conditioners are prone to frequently enter the defrosting state, the present invention provides a heating control method for multi-connected air conditioners, a multi-connected air conditioner, and a storage medium, which can prevent a single outdoor unit from over-running by reasonably allocating the heating load and improve the operation stability of the multi-connected air conditioner.

[0005] The technical solution adopted by the present invention is to design a heating control method for multi-connected air conditioners, including:

[0006] After the multi-connected air conditioner enters the heating operation, calculate the heating load of the multi-connected air conditioner and detect the available outdoor units that can operate currently;

[0007] If the sum of the capacities of each available outdoor unit with the same capacity is greater than the heating load / β1, select the number of units to be turned on among the available outdoor units with the lowest capacity that meet the requirements, and the turned-on available outdoor units evenly divide the heating load;

[0008] If the sum of the capacities of at least one type of available outdoor unit with the same capacity is between the heating load / β2 and the heating load / β1, all the available outdoor units with the lowest capacity that meet the requirements are turned on, and the turned-on available outdoor units evenly divide the heating load;

[0009] If the sum of the capacities of each type of available outdoor unit with the same capacity is less than the heating load / β2, the number of units to be turned on is selected from the available outdoor units that meet the requirements in ascending order of capacity, and the turned-on available outdoor units distribute the heating load according to the capacity ratio;

[0010] Wherein, β1 and β2 are proportionality coefficients, and β1 < β2.

[0011] Further, the number of units to be turned on is the smallest positive integer that satisfies the heating load ≤ the sum of the total capacities of the selected available outdoor units × β2.

[0012] Further, the multi-connected unit heating control method further includes:

[0013] After turning on the corresponding available outdoor units, when the operation reaches the set time, detect the low pressure value and load rate of the turned-on outdoor units;

[0014] Judge whether the highest low pressure value - the lowest low pressure value ≥ the set value;

[0015] If so, it is determined that the operation state of the multi-connected unit is not good, the turned-on outdoor unit with the lowest low pressure value is regarded as the faulty outdoor unit, reduce the load rate of the faulty outdoor unit, and redistribute the heating load reduced by the faulty outdoor unit.

[0016] Further, after determining that the operation state of the multi-connected unit is not good, judge whether there is a healthy outdoor unit with a low pressure value ≥ the standard value and a load rate ≤ β2. If so, distribute the heating load reduced by the faulty outdoor unit to the healthy outdoor unit.

[0017] In some embodiments, the standard value is the median of all low pressure values.

[0018] Further, distributing the heating load reduced by the faulty outdoor unit to the healthy outdoor unit includes: reducing the load rate of the faulty outdoor unit by a set proportion, and the healthy outdoor units distribute the heating load reduced by the faulty outdoor unit according to the capacity ratio.

[0019] Further, the multi-connected unit heating control method further includes: if there is no healthy outdoor unit with a low pressure value ≥ the standard value and a load rate ≤ β2, judge whether the load rate of the faulty outdoor unit ≥ β3. If so, select the outdoor unit with the lowest capacity among the unturned-on available outdoor units as a supplementary outdoor unit to turn on, and distribute the heating load reduced by the faulty outdoor unit to the supplementary outdoor unit; wherein, β3 is a proportionality coefficient, and β1 < β3 < β2.

[0020] In some embodiments, allocating the reduced heating load of a defective outdoor unit to a supplementary outdoor unit includes: calculating the proportional value of the reduction in the load rate of the defective outdoor unit, where the proportional value = capacity of the supplementary outdoor unit / (capacity of the defective outdoor unit + capacity of the supplementary outdoor unit) × 100%, and the supplementary outdoor unit undertakes the reduced heating load of the defective outdoor unit.

[0021] Further, if the highest low pressure value - the lowest low pressure value < set value, and / or the load rate of the defective outdoor unit < β3, and / or there is no available outdoor unit that is not turned on, then return to the step of re-detecting the low pressure value and load rate of the turned-on outdoor units.

[0022] Further, the multi-unit heating control method further includes: after reallocating the reduced heating load of the defective outdoor unit, when the operation reaches the set time, return to the step of re-detecting the low pressure value and load rate of the turned-on outdoor units.

[0023] Further, the multi-unit heating control method further includes: during the heating operation of the multi-unit, when the rotation condition is reached, execute the rotation rule, and return to the step of recalculating the heating load of the multi-unit and detecting the available outdoor units that can currently operate.

[0024] The present invention also provides a multi-unit, including: at least two outdoor units installed in parallel, and the controller of the multi-unit executes the above multi-unit heating control method.

[0025] In some embodiments, the multi-unit is a heat pump multi-unit.

[0026] The present invention also provides a storage medium for storing a computer program, and when the computer program runs, it executes the above multi-unit heating control method.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. During heating operation, preferentially allocate the heating load to outdoor units of the same capacity, and multiple outdoor units share the heating load together, thereby increasing the area of the outdoor heat exchanger participating in the work, increasing the evaporation temperature of the system, thereby reducing the frosting rate of the multi-unit and preventing the system from frequently entering the defrosting state;

[0029] 2. Detect the low pressure values and load rates of different outdoor units, and reallocate the heating load when the operation state of the multi-unit is not good, preventing the low pressure values of some outdoor units from being too low and entering the defrosting state more frequently. Description of the Drawings

[0030] The present invention will be described in detail below in conjunction with the embodiments and the drawings, where:

[0031] Figure 1 is a schematic diagram of the load allocation process of the heating control method of the present invention;

[0032] Figure 2 It is a schematic diagram of the load adjustment process of the heating control method of the present invention. Specific embodiments

[0033] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clear and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0034] The heating control method proposed by the present invention is applicable to multi-connected air conditioners, including but not limited to heat pump multi-connected air conditioners. The multi-connected air conditioner has a plurality of outdoor units installed in parallel. The outdoor unit includes a compressor, an outdoor heat exchanger, etc. Any one outdoor unit can independently perform refrigerant circulation with at least one indoor unit of the multi-connected air conditioner, and can also perform refrigerant circulation with at least one indoor unit of the multi-connected air conditioner together with other outdoor units. The number of outdoor units with the same capacity is one or more. Here, the capacity refers to the rated heating capacity of the outdoor unit, generally the heating capacity marked on the nameplate, or the full-load heating capacity can be calculated in real time according to parameters such as ambient temperature. At this time, the capacity of the outdoor unit can be replaced by this value. The design concept of the heating control method is that under heating operation, the heating load is preferentially distributed to the outdoor units with the same capacity, and the number of units started is increased, so as to increase the evaporation temperature of the system, reduce the frosting rate of the outdoor unit, and prevent the system from frequently entering the defrosting state.

[0035] As Figure 1 shown, the implementation process of the heating control method will be described in detail below.

[0036] After the multi-connected air conditioner enters the heating operation, calculate the heating load of the multi-connected air conditioner and detect the available outdoor units that can operate currently;

[0037] If the sum of the capacities of the available outdoor units with each same capacity is greater than the heating load / β1 - that is, the heating load < the sum of the capacities of the available outdoor units with the same capacity × β1, it means that the heating load is low. Therefore, select the number of units to start among the available outdoor units with the lowest capacity that meet the requirements, and evenly distribute the heating load to the started available outdoor units;

[0038] If the sum of the capacities of at least one type of available outdoor unit with the same capacity is between the heating load / β2 and the heating load / β1 - that is, the sum of the capacities of the available outdoor units with the same capacity × β1 ≤ the heating load ≤ the sum of the capacities of the available outdoor units with the same capacity × β2, it means that the heating load is normal. Turn on all the available outdoor units with the lowest capacity that meet the requirements, and evenly distribute the heating load to the started available outdoor units;

[0039] If the sum of the capacities of each available outdoor unit with the same capacity is less than the heating load / β2 - that is, the heating load > the sum of the capacities of the available outdoor units with the same capacity × β2, then select the number of units to be turned on from the available outdoor units with lower capacity to higher capacity, and distribute the heating load according to the capacity ratio of the turned-on available outdoor units. For ease of understanding, taking a heating load of 50 kw as an example, the available outdoor units selected are one 30 kw and one 70 kw. Then, the heating load assigned to the 30 kw outdoor unit is 50 × 30 / (30 + 70) = 15 kw, and the heating load assigned to the 70 kw outdoor unit is 50 × 70 / (30 + 70) = 35 kw.

[0040] The present invention formulates different startup strategies according to the magnitude of the heating load, distributes the heating load to the outdoor units that meet the requirements and have lower capacity, and tries to ensure that the capacities of the turned-on outdoor units are the same and the number is large. This not only reduces the excessive low-pressure difference between different outdoor units caused by refrigerant drift, but also increases the area of the outdoor heat exchanger participating in the work, improves the evaporation temperature of the system, reduces the frosting rate of the multi-connected air conditioner, and prevents the system from frequently entering the defrosting state.

[0041] It should be noted that when the system starts up and operates for heating, first check the outdoor unit available for this startup operation after the last rotation. This outdoor unit is the available outdoor unit. Select the number of units to be turned on and distribute the heating load among the available outdoor units for this operation to avoid overusing some outdoor units. The rotation conditions and the corresponding rotation rules can be designed according to the actual situation. For example, when the cumulative operation time of a certain outdoor unit reaches the set working limit value, the rotation condition is reached, and this outdoor unit is identified as a non-available outdoor unit. When the downtime of the non-available outdoor unit reaches the set rest limit value, the cumulative operation time is reset. The above β1 and β2 are proportionality coefficients, and β1 < β2. The performance and stability of the outdoor unit of the multi-connected air conditioner are the best when it operates between capacity × β1 and capacity × β2. Generally speaking, β1 is 30% and β2 is 70%. In practical applications, the values of β1 and β2 can be designed according to the specific model and usage requirements, etc. The present invention does not make special restrictions on this.

[0042] In some embodiments of the present invention, the number of turned-on units is the smallest positive integer that satisfies the heating load ≤ the sum of the total capacities of the selected available outdoor units × β2. More precisely, for the case where the sum of the capacities of the available outdoor units of each capacity is greater than the heating load / β1, the number of turned-on units is selected from the available outdoor units with the lowest capacity that meets the requirements, and the calculation method of the number of turned-on units is the smallest positive integer not less than the heating load / (the capacity of the available outdoor unit × β2). That is to say, if there is a remainder when the heating load / (the capacity of the available outdoor unit × β2), it is rounded up, and the load rates of the turned-on available outdoor units are all controlled below β2; for the case where the sum of the capacities of the available outdoor units of each capacity is less than the heating load / β2, the number of turned-on units is selected from the available outdoor units that meet the requirements from the lowest capacity to the highest capacity. The calculation method of the number of turned-on units is to calculate the sum of the capacities × β2 by stacking from the smallest capacity until the heating load ≤ the sum of the total capacities of the selected available outdoor units × β2, and the load rates of the turned-on available outdoor units are all controlled below β2.

[0043] In the above embodiments, the calculation method of the number of turned-on units can ensure that after the heating load is distributed, the load rates of each turned-on available outdoor unit are within the optimal range, effectively improving the operation stability and energy efficiency of the multi-connected air conditioner. It should be understood that during the heating operation of the multi-connected air conditioner, when the rotation condition is reached, the rotation rule is executed. Since the available outdoor units change, it is necessary to return to calculate the heating load of the multi-connected air conditioner and detect the currently operable available outdoor units, and redistribute the heating load.

[0044] As Figure 2 shown, in still some other embodiments of the present invention, the multi-connected air conditioner heating control method further includes:

[0045] After turning on the corresponding available outdoor unit, when the operation reaches the set time, detect the low pressure value and load rate of the turned-on outdoor units;

[0046] Judge whether the highest low pressure value - the lowest low pressure value ≥ the set value;

[0047] If so, it is determined that the operation state of the multi-connected air conditioner is not good, the difference in the low pressure values of the turned-on outdoor units is large, and there is a risk of frosting. At this time, the turned-on outdoor unit with the lowest low pressure value is regarded as a defective outdoor unit, reduce the load rate of the defective outdoor unit, and redistribute the heating load reduced by the defective outdoor unit.

[0048] In the above embodiments, by judging whether the low pressure difference between different outdoor units is too large - equal to or greater than the set value, the frosting risk of the multi-connected air conditioner is detected in time, and then the load rate of the defective outdoor unit is adjusted, and the heating load reduced by the defective outdoor unit is redistributed. On the basis of meeting the heating demand, the low pressure value of the defective outdoor unit is quickly increased to avoid triggering the multi-connected air conditioner to enter the defrosting state, optimizing the use experience and operation stability of the multi-connected air conditioner.

[0049] It should be understood that the load rate of a single outdoor unit is the heating load borne by the outdoor unit / the capacity of the outdoor unit × 100%. The low-pressure value is the saturation temperature corresponding to the evaporation pressure, generally referring to the saturation temperature value corresponding to the pressure value detected by the low-pressure sensor on the suction side of the compressor. The set value above can be 5°C, or it can be designed according to specific usage requirements, etc. The present invention does not make special restrictions on this.

[0050] There are various ways to redistribute the heating load. For example, find a good outdoor unit with a good operating state and surplus capacity among the already started outdoor units, or find an appropriate supplementary outdoor unit among the unstarted outdoor units. Only the feasible embodiments of the present invention are provided below for illustration. In actual applications, the distribution method can be designed according to actual usage requirements.

[0051] In the first case, after determining that the multi-connected unit is in a poor operating state, determine whether there is a good outdoor unit, that is, find a good outdoor unit among the already started outdoor units. The condition for a good outdoor unit is that the low-pressure value ≥ the standard value, which indicates a good operating state, and the load rate ≤ β2, which indicates the ability to bear more load. If there is a good outdoor unit, then allocate the reduced heating load of the bad outdoor unit to the good outdoor unit. Selecting a good outdoor unit among the already started outdoor units can reduce the start-stop times of the compressor, and the stability of the multi-connected unit is better.

[0052] To make the value of the standard value more accurate, calculate the median of the low-pressure values of all the already started outdoor units. The median can truly reflect the normal low-pressure value of the current outdoor unit. Therefore, use this median as the standard value. If the low-pressure value of an already started outdoor unit ≥ the standard value, it means that its low-pressure value is equal to or higher than the normal low-pressure value of the current outdoor unit, with a good operating state and a lower frosting risk. Of course, in actual applications, other methods can also be used to calculate the standard value, or the standard value can be designed as a fixed value. The present invention does not make special restrictions on this.

[0053] Based on the above first case, in some embodiments of the present invention, the load rate of the bad outdoor unit is reduced by a set ratio, and the good outdoor units allocate the reduced heating load of the bad outdoor unit according to the capacity ratio. The set ratio here can be 10% or other values, and it is designed according to specific needs in actual applications. For easy understanding, taking the example that the heating load of the bad outdoor unit is reduced by 10 kw, the capacity of one good outdoor unit is 20 kw, and the capacity of another good outdoor unit is 30 kw. Then the capacity ratio of these two good outdoor units is 2:3. The newly added heating load of the former is 4 kw, and the newly added heating load of the latter is 6 kw.

[0054] In the second case, after determining that the operation status of the multi-connected unit is not good, it is judged whether there is a good outdoor unit. If there is no good outdoor unit, it is judged whether the load rate of the bad outdoor unit ≥ β3. If so, it is judged whether there is an available outdoor unit that is not turned on. If there is an available outdoor unit that is not turned on, the one with the lowest capacity among the available outdoor units that are not turned on is selected as the supplementary outdoor unit to be turned on, and the reduced heating load of the bad outdoor unit is allocated to the supplementary outdoor unit.

[0055] Among them, β3 is a proportionality coefficient, and β1 < β3 < β2. The closer the value of β3 is to β1, the condition that the load rate ≥ β3 will be triggered when the bad outdoor unit undertakes less heating load, and the scale of load adjustment is narrow, which is likely to frequently trigger load adjustment actions and is not conducive to the operation stability of the multi-connected unit. Therefore, it is preferred that the value of β3 is close to β2. For example, when β3 is 60%, the condition that the load rate ≥ β3 will be triggered only when the bad outdoor unit undertakes more heating load. The scale of load adjustment is wide, which can not only effectively avoid excessive load and easy frosting of some outdoor units, but also minimize load adjustment actions to the greatest extent and improve the operation stability of the multi-connected unit.

[0056] Based on the above second case, in some embodiments of the present invention, the reduced proportion value of the load rate of the bad outdoor unit is calculated. The proportion value = capacity of the supplementary outdoor unit / (capacity of the bad outdoor unit + capacity of the supplementary outdoor unit) × 100%. The supplementary outdoor unit undertakes the reduced heating load of the bad outdoor unit. For the sake of easy understanding, taking the capacity of the supplementary outdoor unit as 10kw and the capacity of the bad outdoor unit as 30kw as an example, the proportion value = 10kw / (30kw + 10kw) × 100% = 25%. The load rate of the bad outdoor unit is reduced by 25%, and the heating load borne by the supplementary outdoor unit is the heating load of the bad outdoor unit × 25%.

[0057] It should be noted that after redistributing the heating load reduced by the defective outdoor units, when the operation reaches the set time, return to the step of re-detecting the low-pressure value and load rate of the turned-on outdoor units. The set time in this article can be set to 10 minutes, or it can be designed according to actual usage requirements. Additionally, in the above judgment conditions, if the highest low-pressure value - the lowest low-pressure value < the set value, it is determined that the multi-connected unit is operating well, and the difference in the low-pressure values of the turned-on outdoor units is small, and there is no need to adjust the heating load. Return to the step of re-detecting the low-pressure value and load rate of the turned-on outdoor units; if it is determined that the multi-connected unit is operating poorly and there is no good outdoor unit and the load rate of the defective outdoor unit < β3, it means that the current operating state of the defective outdoor unit is acceptable and the frosting risk is small, and there is no need to adjust the heating load. Return to the step of re-detecting the low-pressure value and load rate of the turned-on outdoor units; if it is determined that the multi-connected unit is operating poorly, there is no good outdoor unit, the load rate of the defective outdoor unit ≥ β3, and there is no available unturned-on outdoor unit, it means that the current operating state of the defective outdoor unit is poor and the frosting risk is large, but currently there is no good outdoor unit or supplementary outdoor unit that can bear the heating load, and the heating load cannot be adjusted. Forcefully return to the step of re-detecting the low-pressure value and load rate of the turned-on outdoor units.

[0058] As Figure 1 shown, for ease of understanding, the following uses an application example of the present invention to illustrate the load distribution process of the heating control method for multi-connected units:

[0059] Step S100: The multi-connected unit enters the heating operation;

[0060] Step S101: Calculate the heating load of the multi-connected unit and detect the currently available outdoor units that can operate;

[0061] Step S102: Compare the heating load with the sum of the capacities of the available outdoor units of the same capacity. If the sum of the capacities of each available outdoor unit of the same capacity is greater than the heating load / 30% - that is, the heating load < the sum of the capacities of the available outdoor units of the same capacity × 30%, then execute Step S103. If the sum of the capacities of at least one available outdoor unit of the same capacity is between the heating load / 70% and the heating load / 30% - that is, the sum of the capacities of the available outdoor units of the same capacity × 30% ≤ the heating load ≤ the sum of the capacities of the available outdoor units of the same capacity × 70%, then execute Step S106. If the sum of the capacities of each available outdoor unit of the same capacity is less than the heating load / 70% - that is, the heating load > the sum of the capacities of the available outdoor units of the same capacity × 70%, then execute Step S108;

[0062] Step S103: Select the number of units to be turned on from the available outdoor units with the lowest capacity that meet the requirements;

[0063] Step S104: The number of units to be turned on = round up (heating load / (the capacity of this available outdoor unit × β2));

[0064] Step S105: Evenly distribute the heating load to the available external units that are turned on, and execute Step S110;

[0065] Step S106: Turn on all the available external units with the lowest capacity that meet the requirements;

[0066] Step S107: Evenly distribute the heating load to the available external units that are turned on, and execute Step S110;

[0067] Step S108: Select the number of units to be turned on from the available external units that meet the requirements, starting from the lowest capacity to the highest capacity;

[0068] Step S109: Distribute the heating load according to the capacity ratio of the available external units that are turned on;

[0069] Step S110: After running for 10 minutes, enter Step S200.

[0070] Step S111: When the rotation condition is reached, execute the rotation rule and return to Step S101.

[0071] As Figure 2 shown, for the sake of easy understanding, the following uses an application example of the present invention to illustrate the load adjustment process of the multi-connected unit heating control method:

[0072] Step S200: Enter the heating load adjustment process;

[0073] Step S201: Detect the low-pressure value of the external units that have been turned on, calculate the median of all low-pressure values, and detect the load rate of each turned-on external unit;

[0074] Step S202: Judge whether the highest low-pressure value - the lowest low-pressure value ≥ the set value. If so, execute Step S203. If not, return to Step S201;

[0075] Step S203: Select the healthy external units with a low-pressure value ≥ the median and a load rate ≤ 70%;

[0076] Step S204: Judge whether the number of healthy external units > 0. If so, execute Step S205. If not, execute Step S206;

[0077] Step S205: Take the external unit with the lowest low-pressure value among the turned-on external units as the unhealthy external unit, reduce the load rate of the unhealthy external unit by 10%, and distribute the reduced heating load of the unhealthy external unit to the healthy external units according to the capacity ratio, and execute Step S210;

[0078] Step S206: Judge whether the load rate of the unhealthy external unit ≥ 60%. If so, execute Step S207. If not, return to Step S201;

[0079] Step S207: Determine whether the number of available external units that are not turned on > 0. If so, execute Step S208; if not, return to Step S201;

[0080] Step S208: Select one external unit with the lowest capacity from the available external units that are not turned on and turn it on as the supplementary external unit;

[0081] Step S209: Calculate the proportional value of the reduction in the load rate of the defective external unit. The proportional value = capacity of the supplementary external unit / (capacity of the defective external unit + capacity of the supplementary external unit) × 100%. The supplementary external unit undertakes the reduced heating load of the defective external unit;

[0082] Step S210: After running for 10 minutes, enter Step S201.

[0083] The present invention also provides a multi-split air conditioner having at least two externally mounted units installed in parallel, including but not limited to a heat pump multi-split air conditioner. The controller of the multi-split air conditioner executes the above-described heating control method, reasonably distributes the heating load when entering the heating operation, prevents excessive wear of a single external unit, increases the area of the outdoor heat exchanger participating in the work, raises the evaporation temperature of the system, thereby reducing the frosting rate of the external unit, preventing the system from frequently entering the defrosting state, and detects the low pressure and capacity between different units during the heating operation to change the heating load distribution between the units, preventing the low pressure value of some external units from being relatively low and entering the defrosting more frequently. The control logic of the heating control method has been described in detail above.

[0084] The present invention also provides a storage medium for storing a computer program, and the computer program, when running, executes the above-described heating control method.

[0085] It should be noted that the terms used above are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. When the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof. The execution order of actions, steps, etc. in the devices and methods shown in the specification and drawings can be implemented in any order as long as there is no specific limitation on the order and the output of the previous process is not used in the subsequent process. The similar sequential terms used for convenience of description do not mean that they must be implemented in such an order.

[0086] Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such technologies, methods, and devices shall be regarded as part of the authorized specification. In all examples shown and discussed herein, any specific values should be construed as merely exemplary and not as a limitation. Thus, other examples of the exemplary embodiments may have different values. It should be noted that like reference numerals and letters denote like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof in subsequent figures is not required.

[0087] The foregoing is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. The heat control method for a multi-connected unit, characterized in that Including: After the multi-connected air conditioner enters the heating operation, calculate the heating load of the multi-connected air conditioner and detect the available outdoor units that can operate currently; If the sum of the capacities of each available outdoor unit with the same capacity is greater than the heating load / β1, select the number of units to be turned on among the available outdoor units with the lowest capacity that meet the requirements, and the turned-on available outdoor units evenly divide the heating load; If the sum of the capacities of at least one type of available outdoor unit with the same capacity is between the heating load / β2 and the heating load / β1, turn on all the available outdoor units with the lowest capacity that meet the requirements, and the turned-on available outdoor units evenly divide the heating load; If the sum of the capacities of each available outdoor unit with the same capacity is less than the heating load / β2, select the number of units to be turned on from the available outdoor units that meet the requirements in ascending order of capacity, and the turned-on available outdoor units distribute the heating load according to the capacity ratio; Wherein, β1 and β2 are proportionality coefficients, and β1 < β2.

2. The multi-unit air conditioner heat control method according to claim 1, wherein The number of units to be turned on is the smallest positive integer that satisfies the heating load ≤ the sum of the total capacities of the selected available outdoor units × β2.

3. The multi-unit air conditioner heating control method according to claim 1, characterized in that, Also including: After turning on the corresponding available outdoor units, when the operation reaches the set time, detect the low-pressure value and load rate of the turned-on outdoor units; Judge whether the highest low-pressure value - the lowest low-pressure value ≥ the set value; If so, determine that the operation state of the multi-connected air conditioner is poor, regard the turned-on outdoor unit with the lowest low-pressure value as the defective outdoor unit, reduce the load rate of the defective outdoor unit, and re-distribute the reduced heating load of the defective outdoor unit; 4. The multi-unit heat control method according to claim 3, characterized in that, After determining that the operation state of the multi-connected air conditioner is poor, judge whether there is a healthy outdoor unit with a low-pressure value ≥ the standard value and a load rate ≤ β2. If so, distribute the reduced heating load of the defective outdoor unit to the healthy outdoor unit; 5. The multi-unit heating control method according to claim 4, characterized in that, The standard value is the median of all the low-pressure values.

6. The multi-unit heat control method according to claim 4, characterized in that, Distributing the reduced heating load of the defective outdoor unit to the healthy outdoor unit includes: reducing the load rate of the defective outdoor unit by a set proportion, and the healthy outdoor units distribute the reduced heating load of the defective outdoor unit according to the capacity ratio; 7. The multi-unit heat control method according to claim 4, wherein Also including: If there is no healthy outdoor unit with a low-pressure value ≥ the standard value and a load rate ≤ β2, judge whether the load rate of the defective outdoor unit ≥ β3. If so, select the one with the lowest capacity from the unturned-on available outdoor units as the supplementary outdoor unit to be turned on, and distribute the reduced heating load of the defective outdoor unit to the supplementary outdoor unit; Wherein, β3 is a proportionality coefficient, and β1 < β3 < β2.

8. The multi-unit heat control method according to claim 7, characterized in that Distributing the reduced heating load of the defective outdoor unit to the supplementary outdoor unit includes: calculating the proportion value of the reduction of the load rate of the defective outdoor unit, the proportion value = the capacity of the supplementary outdoor unit / (the capacity of the defective outdoor unit + the capacity of the supplementary outdoor unit) × 100%, and the supplementary outdoor unit undertakes the reduced heating load of the defective outdoor unit; 9. The multi-unit heat control method according to claim 7, wherein, If the highest low-pressure value - the lowest low-pressure value < the set value, and / or the load rate of the defective outdoor unit < β3, and / or there is no unturned-on available outdoor unit, return to the step of re-detecting the low-pressure value and load rate of the turned-on outdoor units; 10. The multi-unit heat control method according to claim 3, characterized in that, Also including: After re-distributing the reduced heating load of the defective outdoor unit, when the operation reaches the set time, return to the step of re-detecting the low-pressure value and load rate of the turned-on outdoor units; 11. The multi-connected unit heating control method according to any one of claims 1 to 10, characterized in that Also including: During the heating operation of the multi-connected air conditioner, when the rotation condition is reached, the rotation rule is executed, and the steps of recalculating the heating load of the multi-connected air conditioner and detecting the available outdoor units that can operate currently are returned.

12. Multi-connected air conditioner, comprising: At least two outdoor units are installed in parallel, characterized in that the controller of the multi-connected air conditioner executes the multi-connected air conditioner heating control method according to any one of claims 1 to 11.

13. The multi-connected air conditioner according to claim 12, wherein The multi-connected air conditioner is a heat pump multi-connected air conditioner.

14. A storage medium for storing a computer program, characterized in that, When the computer program runs, it executes the multi-connected air conditioner heating control method according to any one of claims 1 to 11.

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