Control method for air conditioning heat pump system, and air conditioning heat pump system

Abstract

To provide a control method for an air conditioning heat pump system that can improve the defrosting effect of the whole system.SOLUTION: A control method includes: acquiring evaporation capacity information on n outdoor units when an air conditioning pump system is in an alternate defrosting mode; sectioning, based upon the evaporation capacity information, the n outdoor units into m first outdoor units and k (n=m+k) second outdoor units whose sum of evaporation capacity parameters is equal to or less than the sum of evaporation capacity parameters of the m first outdoor units; controlling the m first outdoor units to operate in a heating mode and controlling the k second outdoor units to operate in a defrosting mode; and controlling the m first outdoor units to operate in the defrosting mode and controlling the k second outdoor units to operate in the heating mode after the k second outdoor units complete the defrosting.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present application relates to the field of air conditioning technology, and particularly to a control method for an air conditioning heat pump system and an air conditioning heat pump system.

Background Art

[0002] In related technologies, in order to ensure the comfort and reliability of an air conditioner, when the frost layer is thick, the unit in the air conditioning heat pump system operates in the defrosting mode. In the defrosting mode, the outdoor unit of the air conditioner is in the condensation mode, and the indoor unit is in the cooling mode. However, when the frost layer is thick, the heat absorption capacity of the heat exchanger in the evaporator state is poor, which affects the defrosting effect of the heat exchanger in the condenser state, resulting in the problem that defrosting cannot be completed.

Summary of the Invention

Problems to be Solved by the Invention

[0003] Embodiments of the present application provide a control method for an air conditioning heat pump system and an air conditioning heat pump system for solving the problem of incomplete defrosting in an air conditioning heat pump system.

Means for Solving the Problems

[0004] In order to solve the above technical problems, the present application is realized as follows.

[0005] According to a first aspect, an embodiment of the present application provides a control method for an air-conditioning heat pump system. The air-conditioning heat pump system includes an indoor unit and n (n is an integer greater than 1) outdoor unit units. When the air-conditioning heat pump system is in an alternating defrosting mode, the control method is an evaporation capacity parameter used to represent the evaporation capacity during the operation process of the corresponding outdoor unit unit, and includes obtaining evaporation capacity information of the n outdoor unit units including n evaporation capacity parameters corresponding one-to-one to the n outdoor unit units; based on the evaporation capacity information, dividing the n outdoor unit units into m (m is an integer greater than 0) first outdoor unit units and k (k is an integer greater than 0, and the sum of m and k is n) second outdoor unit units, where the sum of the evaporation capacity parameters of the k second outdoor unit units is less than or equal to the sum of the evaporation capacity parameters of the m first outdoor unit units; controlling the m first outdoor unit units to operate in a heating mode, controlling the k second outdoor unit units to operate in a defrosting mode; after the defrosting of the k second outdoor unit units is completed, controlling the m first outdoor unit units to operate in a defrosting mode, and controlling the k second outdoor unit units to operate in a heating mode.

[0006] As an alternative embodiment, each of the first outdoor unit units includes one first compressor and one first heat exchanger, and each of the second outdoor unit units includes one second compressor and one second heat exchanger. When the m first outdoor unit units operate in the heating mode and the k second outdoor unit units operate in the defrosting mode, the first compressor is in an operating state, the second compressor is in a non-operating state, the heat exchanger in the first outdoor unit unit forms an evaporator in the air-conditioning heat pump system, the heat exchanger in the second outdoor unit unit forms a condenser in the air-conditioning heat pump system, and in any of the second outdoor unit units, the input end of the second heat exchanger communicates with the output end of each first compressor, and the output end of the second heat exchanger communicates with the input end of each first compressor. When the m first outdoor unit units operate in the defrosting mode and the k second outdoor unit units operate in the heating mode, the first compressor is in a non-operating state, the second compressor is in an operating state, the heat exchanger in the first outdoor unit unit forms a condenser in the air-conditioning heat pump system, the heat exchanger in the second outdoor unit unit forms an evaporator in the air-conditioning heat pump system, and in any of the first outdoor unit units, the input end of the first heat exchanger communicates with the output end of each second compressor, and the output end of the first heat exchanger communicates with the input end of each second compressor.

[0007] As an alternative embodiment, each of the first outdoor unit units includes one first compressor and one first heat exchanger, and each of the second outdoor unit units includes one second compressor and one second heat exchanger. When the m first outdoor unit units operate in the heating mode and the k second outdoor unit units operate in the defrosting mode, the first compressor is in an operating state, the second compressor is in an operating state, the heat exchanger in the first outdoor unit unit forms an evaporator in the air-conditioning heat pump system, the heat exchanger in the second outdoor unit unit forms a condenser in the air-conditioning heat pump system, and in any one of the second outdoor unit units, the input end of the second compressor communicates with the output end of each first compressor, the output end of the second compressor communicates with the input end of the second heat exchanger, and the output end of the second heat exchanger communicates with the input end of each first compressor. When the m first outdoor unit units operate in the defrosting mode and the k second outdoor unit units operate in the heating mode, the first compressor is in an operating state, the second compressor is in an operating state, the heat exchanger in the first outdoor unit unit forms a condenser in the air-conditioning heat pump system, the heat exchanger in the second outdoor unit unit forms an evaporator in the air-conditioning heat pump system, and in any one of the first outdoor unit units, the input end of the first compressor communicates with the output end of each second compressor, the output end of the first compressor communicates with the input end of the first heat exchanger, and the output end of the first heat exchanger communicates with the input end of each second compressor.

[0008] As an alternative embodiment, when the m first outdoor unit units operate in the heating mode and the k second outdoor unit units operate in the defrosting mode, the method further includes controlling the frequency of the first compressor based on the exhaust pressure of the first compressor and controlling the frequency of the second compressor based on the compression ratio of the second compressor. When the m first outdoor unit units operate in the defrosting mode and the k second outdoor unit units operate in the heating mode, the method further includes controlling the frequency of the first compressor based on the compression ratio of the first compressor and controlling the frequency of the second compressor based on the exhaust pressure of the second compressor.

[0009] As an optional embodiment, controlling the frequency of the first compressor based on the discharge pressure of the first compressor and controlling the frequency of the second compressor based on the compression ratio of the second compressor includes controlling the frequency of the first compressor to be smaller when the discharge pressure of the first compressor is equal to or greater than a first threshold, and controlling the frequency of the first compressor to be larger when the discharge pressure of the first compressor is less than the first threshold; and setting the frequency of the second compressor to a first frequency value that is a times the frequency of the first compressor when the compression ratio of the second compressor is equal to or greater than a second threshold, and setting the frequency of the second compressor to a second frequency value that is b times the frequency of the first compressor (b>a) when the compression ratio of the second compressor is less than the second threshold. Controlling the frequency of the first compressor based on the compression ratio of the first compressor and controlling the frequency of the second compressor based on the discharge pressure of the second compressor includes setting the frequency of the first compressor to a third frequency value that is a times the frequency of the second compressor when the compression ratio of the first compressor is equal to or greater than the second threshold, and setting the frequency of the first compressor to a fourth frequency value that is b times the frequency of the second compressor when the compression ratio of the first compressor is less than the second threshold, and controlling the frequency of the second compressor to be smaller when the discharge pressure of the second compressor is equal to or greater than the first threshold, and controlling the frequency of the second compressor to be larger when the discharge pressure of the second compressor is less than the second threshold.

[0010] In an alternative embodiment, the evaporation capacity parameter is determined based on a capacity parameter of the outdoor unit or a frost thickness value of the outdoor unit, wherein the evaporation capacity parameter and the capacity parameter exhibit a positive correlation, and the evaporation capacity parameter and the frost thickness value exhibit a negative correlation.

[0011] In an alternative embodiment, the frost thickness value and the power ratio of the outdoor unit, which is the ratio between the peak power of a fan in the outdoor unit and the operating power of the fan, show a positive correlation.

[0012] As an alternative embodiment, when the air-conditioning heat pump system is in the alternating defrosting mode, before obtaining the evaporation capacity information of the n outdoor unit units, the method further includes a power ratio that is the ratio of the peak power of the fan in the outdoor unit unit to the operating power of the fan, obtaining the power ratio of each of the n outdoor unit units among the n outdoor unit units to obtain n power ratios; when at least one of the n power ratios is greater than or equal to a third threshold, controlling the air-conditioning heat pump system to shift to a normal defrosting mode in which the heat exchanger in the n outdoor unit units forms a condenser and the heat exchanger in the indoor unit unit forms an evaporator; and when all of the n power ratios are less than the third threshold, controlling the air-conditioning heat pump system to shift to the alternating defrosting mode.

[0013] As an alternative embodiment, when n is equal to 2, the m first outdoor unit units include one outdoor unit unit among the n outdoor unit units with the largest value of the evaporation capacity parameter, and the k second outdoor unit units include one outdoor unit unit among the n outdoor unit units with the smallest value of the evaporation capacity parameter. When n is equal to 3, the m first outdoor unit units include two outdoor unit units among the n outdoor unit units with the smaller values of the evaporation capacity parameter, and the k second outdoor unit units include one outdoor unit unit among the n outdoor unit units with the largest value of the evaporation capacity parameter. When n is equal to 4, the m first outdoor unit units include two outdoor unit units among the n outdoor unit units with the larger values of the evaporation capacity parameter, and the k second outdoor unit units include two outdoor unit units among the n outdoor unit units with the smaller values of the evaporation capacity parameter.

[0014] According to a second aspect, an embodiment of the present application provides an air-conditioning heat pump system including a controller, an indoor unit, a first transmission pipeline, a second transmission pipeline, and n (n is an integer greater than 1) outdoor units. The indoor unit and the n outdoor units are electrically connected to the controller respectively. Each of the outdoor units includes a storage tank, a compressor, a heat exchanger, a first four-way valve, a second four-way valve, an electronic expansion valve, a first pipeline, and a second pipeline. In each outdoor unit, the output end of the storage tank and the input end of the compressor are connected through a pipeline. The output end of the compressor and the E end of the first four-way valve are connected through a pipeline. The D end of the first four-way valve and the D end of the second four-way valve are connected through a pipeline. The C end of the second four-way valve and the input end of the heat exchanger are connected through a pipeline. The output end of the heat exchanger is connected to the first end of the first pipeline. The electronic expansion valve is provided in the first pipeline. The second end of the first pipeline forms the first external port of the outdoor unit. The S end of the second four-way valve and the C end of the first four-way valve are connected through a pipeline. The S end of the first four-way valve and the input end of the storage tank are connected through a pipeline. The E end of the second four-way valve is connected to the first end of the second pipeline. The second end of the second pipeline forms the second external port of the outdoor unit. The first transmission pipeline includes one input end connected to the output end of the indoor unit and n first connection ends connected to the n first external ports of the n outdoor units in a one-to-one correspondence. The second transmission pipeline includes one output end connected to the input end of the indoor unit and n second connection ends connected to the n second external ports of the n outdoor units in a one-to-one correspondence.

[0015] In an optional embodiment, when m first outdoor unit units among the n outdoor unit units are in a heating mode and k second outdoor unit units among the n outdoor unit units are in a defrosting mode, the controller performs control so that the D and E terminals of a first four-way valve in the first outdoor unit are conductive, the S and C terminals of the first four-way valve in the first outdoor unit are conductive, the D and E terminals of a second four-way valve in the first outdoor unit are conductive, the S and C terminals of the second four-way valve in the first outdoor unit are conductive, the D and C terminals of the first four-way valve in the second outdoor unit are conductive, the S and E terminals of the first four-way valve in the first outdoor unit are conductive, the D and C terminals of the first four-way valve in the second outdoor unit are conductive, the S and E terminals of the first four-way valve in the first outdoor unit are conductive, the D and C terminals of the second four-way valve in the second outdoor unit are conductive, and the S and E terminals of the second four-way valve in the second outdoor unit are conductive. Here, the m and the k are each an integer greater than 0, and the sum of the m and the k is the n. When m first outdoor unit units out of the n outdoor unit units are in a defrosting mode and k second outdoor unit units out of the n outdoor unit units are in a heating mode, the controller performs control so that the D and C terminals of the first four-way valve in the first outdoor unit are conductive, the S and E terminals of the first four-way valve in the first outdoor unit are conductive, the D and C terminals of the second four-way valve in the first outdoor unit are conductive, the S and E terminals of the second four-way valve in the first outdoor unit are conductive, the D and E terminals of the first four-way valve in the second outdoor unit are conductive, the S and C terminals of the first four-way valve in the first outdoor unit are conductive, the D and E terminals of the first four-way valve in the second outdoor unit are conductive, the D and E terminals of the first four-way valve in the first outdoor unit are conductive, the D and E terminals of the second four-way valve in the second outdoor unit are conductive, and the S and C terminals of the second four-way valve in the second outdoor unit are conductive. [Effects of the Invention]

[0016] In the embodiments of the present application, when defrosting n outdoor unit units, by defrosting k second outdoor unit units with weak evaporation capacity based on m first outdoor unit units with strong evaporation capacity first, the defrosting effect of the k second outdoor unit units where defrosting is first performed is enhanced. When the defrosting of the k second outdoor unit units is completed, the evaporation capacity of the k second outdoor unit units is significantly improved. Subsequently, since the defrosting of the m first outdoor unit units is performed based on the k second outdoor unit units, the defrosting effect of the m first outdoor unit units where defrosting is next performed is also high, which is beneficial to improving the defrosting effect of the entire air-conditioning heat pump system.

Brief Description of the Drawings

[0017] To more clearly explain the technical aspects of the embodiments of the present application, the drawings that need to be used in the description of the embodiments of the present application are briefly described below. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without creative labor.

[0018]

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BEST MODE FOR CARRYING OUT THE INVENTION

[0019] The following clearly and completely describes the technical aspects in the embodiments of this application in relation to the accompanying drawings in the embodiments of this application. Obviously, the described embodiments are some of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of this application.

[0020] Refer to FIG. 1. FIG. 1 is a flowchart of a control method for an air-conditioning heat pump system provided by an embodiment of this application. The air-conditioning heat pump system includes an indoor unit and n outdoor units. The n is an integer greater than 1. The control method includes the following steps. In step 101, when the air-conditioning heat pump system is in the alternating defrosting mode, obtain the evaporation capacity information of the n outdoor units. The evaporation capacity information includes n evaporation capacity parameters that correspond one-to-one to the n outdoor units. The evaporation capacity parameter is used to represent the evaporation capacity during the operation of the corresponding outdoor unit. In step 102, based on the evaporation capacity information, divide the n outdoor units into m (m is an integer greater than 0) first outdoor units and k (k is an integer greater than 0, and the sum of m and k is n) second outdoor units, where the sum of the evaporation capacity parameters of the k second outdoor units is less than or equal to the sum of the evaporation capacity parameters of the m first outdoor units. In step 103, control the m first outdoor units to operate in the heating mode and control the k second outdoor units to operate in the defrosting mode. In step 104, after the defrosting of the k second outdoor units is completed, control the m first outdoor units to operate in the defrosting mode and control the k second outdoor units to operate in the heating mode.

[0021] Here, the air conditioning heat pump system may be various types of multi-ion line air conditioning heat pump systems. The air conditioning heat pump system may further include a controller electrically connected to the indoor unit and n outdoor unit units to realize various processes of the control method. The control method is used to realize the defrosting process of the air conditioning heat pump system. The value of the above n is set according to actual needs. For example, the above n is 2, 3, 4, etc.

[0022] In some embodiments of the present application, the air-conditioning heat pump system includes a controller, an indoor unit, a first transmission pipeline, a second transmission pipeline, and n (n is an integer greater than 1) outdoor units, and the indoor unit and the n outdoor units are each electrically connected to the controller. Each of the outdoor units includes a storage tank, a compressor, a heat exchanger, a first four-way valve, a second four-way valve, an electronic expansion valve, a first pipeline, and a second pipeline. And in each outdoor unit, the output end of the storage tank and the input end of the compressor are connected through a pipeline, the output end of the compressor and the E end of the first four-way valve are connected through a pipeline, the D end of the first four-way valve and the D end of the second four-way valve are connected through a pipeline, the C end of the second four-way valve and the input end of the heat exchanger are connected through a pipeline, the output end of the heat exchanger is connected to the first end of the first pipeline, the electronic expansion valve is provided in the first pipeline, the second end of the first pipeline forms the first external port of the outdoor unit, the S end of the second four-way valve and the C end of the first four-way valve are connected through a pipeline, the S end of the first four-way valve and the input end of the storage tank are connected through a pipeline, the E end of the second four-way valve is connected to the first end of the second pipeline, and the second end of the second pipeline forms the second external port of the outdoor unit. The first transmission pipeline includes one input end connected to the output end of the indoor unit and n first connection ends correspondingly connected to the n first external ports of the n outdoor units one-to-one. The second transmission pipeline includes one output end connected to the input end of the indoor unit and n second connection ends correspondingly connected to the n second external ports of the n outdoor units one-to-one. For example, refer to FIG. 2. FIG. 2 is a schematic configuration diagram of the air-conditioning heat pump system when n is equal to 2. Here, in FIG. 2, ODU1 represents the first outdoor unit, ODU2 represents the second outdoor unit, IDU1 represents the first indoor unit, IDU2 represents the second indoor unit, IDU3 represents the third indoor unit, and IDU4 represents the fourth indoor unit. Here, IDU1, IDU2, IDU3, and IDU4 jointly form the indoor unit.CSGL1 represents the first transmission pipeline, CSGL2 represents the second transmission pipeline, 1#Acc represents the storage tank in ODU1, 1#YSJ represents the compressor in ODU1, 1#HEX represents the heat exchanger in ODU1, 1#STF1 represents the first four-way valve in ODU1, 1#STF2 represents the second four-way valve in ODU1, 1#EVO represents the electronic expansion valve in ODU1, 1#GL1 represents the first pipeline in ODU1, and 1#GL2 represents the second pipeline in ODU1. 2#Acc represents the storage tank in ODU2, 2#YSJ represents the compressor in ODU2, 2#HEX represents the heat exchanger in ODU2, 2#STF1 represents the first four-way valve in ODU2, 2#STF2 represents the second four-way valve in ODU2, 2#EVO represents the electronic expansion valve in ODU2, 2#GL1 represents the first pipeline in ODU2, and 2#GL2 represents the second pipeline in ODU2.

[0023] The number of indoor units in the indoor unit unit may be one or more than one. When the indoor unit unit includes at least two indoor units, the at least two indoor units are connected in parallel between the input end of the first transmission pipeline and the output end of the second transmission pipeline. For example, referring to FIG. 2, the indoor unit unit includes four indoor units connected in parallel.

[0024] Among the n outdoor unit units, it is understood that each outdoor unit unit is connected in series with the indoor unit unit via the first transmission pipeline and the second transmission pipeline to form n heat exchange circuits. In this way, each outdoor unit unit forms a complete air conditioning system with the indoor unit unit, and can realize the cooling or heating of the environment where the indoor unit unit is placed. Further, two or more outdoor unit units in the operating state may jointly operate to improve the cooling or heating capacity of the air conditioning heat pump system so as to jointly cool or heat the environment where the indoor unit unit is placed based on the two or more outdoor unit units. When jointly cooling or heating the environment where the indoor unit unit is placed based on two or more outdoor unit units, the two or more outdoor unit units in the operating state are in a parallel state, and each outdoor unit unit and the indoor unit unit are in a series connection state. In this way, the refrigerant output from two or more outdoor unit units in the operating state merges in the second transmission pipeline shown in FIG. 2, the merged refrigerant enters the indoor unit unit, flows through the indoor unit unit again and enters the first transmission pipeline, and is refluxed to two or more outdoor unit units in the operating state by the first transmission pipeline.

[0025] When the m first outdoor unit units operate in the heating mode and the k second outdoor unit units operate in the defrosting mode, the k second outdoor unit units can be made equivalent to a part of the indoor unit unit. In this case, each first outdoor unit unit can be connected in series with any second outdoor unit unit via the first transmission pipeline and the second transmission pipeline to form a complete circuit. At the same time, each first outdoor unit unit is connected in series with the indoor unit unit via the first transmission pipeline and the second transmission pipeline to form a complete circuit, that is, it corresponds to a state where the second outdoor unit unit and the indoor unit unit are connected in parallel. In this way, by controlling the first outdoor unit unit to be in the heating mode, the second outdoor unit unit can be heated so that the frost layer on the surface of the second outdoor unit unit melts, and defrosting of the second outdoor unit unit can be realized.

[0026] For example, referring to FIG. 2, in some embodiments of the present application, the air-conditioning heat pump system includes two outdoor unit units, ODU1 and ODU2, and the indoor unit unit includes four indoor units, IDU1, IDU2, IDU3, and IDU4. The refrigerant flow shown in FIG. 2 is a schematic diagram of the defrosting process of ODU2 based on ODU1, that is, the ODU1 is in the heating mode and the ODU2 is in the defrosting mode. At this time, the n is equal to 2, the ODU1 forms the first outdoor unit unit, and the ODU2 forms the second outdoor unit unit. As shown in FIG. 2, a low-temperature and low-pressure gas refrigerant is stored in the storage tank of ODU1. The compressor in ODU1 consumes power and operates to suck the refrigerant from the storage tank and convert the refrigerant into a high-temperature and high-pressure gas. The high-temperature and high-pressure refrigerant flows through the E end of the first four-way valve in ODU1, the D end of the first four-way valve in ODU1, the D end of the second four-way valve in ODU1, the E end of the second four-way valve in ODU1, and the second pipeline in ODU1 in sequence and enters the second transmission pipeline. A part of the high-temperature and high-pressure refrigerant that enters the second transmission pipeline enters the indoor unit unit, and the other part enters the second pipeline of ODU2. The high-temperature and high-pressure refrigerant that enters the second pipeline flows through the E end of the second four-way valve in ODU2, the S end of the second four-way valve in ODU2, the C end of the first four-way valve in ODU2, the C end of the first four-way valve in ODU2, the D end of the first four-way valve in ODU2, the D end of the second four-way valve in ODU2, and the C end of the second four-way valve in ODU2 in sequence and enters the heat exchanger in ODU2. At this time, the high-temperature and high-pressure gas refrigerant is condensed into a low-temperature and high-pressure liquid refrigerant in the heat exchanger in ODU2 serving as a condenser. A large amount of heat is released from the refrigerant during condensation to heat the heat exchanger in ODU2 and defrost the heat exchanger in ODU2. The low-temperature and high-pressure refrigerant flowing out of the heat exchanger in ODU2 flows through the first pipeline in ODU2 and enters the first transmission pipeline. And during the process of flowing through the first pipeline in ODU2, the electronic expansion valve located in the first pipeline in ODU2 can reduce the pressure of the low-temperature and high-pressure liquid refrigerant and convert it into a low-temperature and low-pressure liquid refrigerant. Correspondingly, the other high-temperature and high-pressure refrigerant flowing through the indoor unit unit also condenses into a liquid and enters the first transmission pipeline. Thereby, the refrigerant entering the first transmission pipeline from ODU2 and the indoor unit unit merges in the first transmission pipeline, and then flows through the first pipeline of ODU1 and enters the heat exchanger of ODU1.The low-temperature and low-pressure liquid refrigerant that enters the heat exchanger of ODU1 absorbs the heat outside the heat exchanger of ODU1 and evaporates into a low-temperature and low-pressure gaseous refrigerant. At this time, the heat exchanger of ODU1 functions as an evaporator, and the other low-temperature and low-pressure refrigerant flows through the C end of the second four-way valve in ODU1, the S end of the second four-way valve in ODU1, the C end of the first four-way valve in ODU1, and the S end of the first four-way valve in ODU1 in sequence and enters the storage tank in ODU1. Thereby, the defrosting process of ODU2 is realized.

[0027] When the defrosting process of ODU2 is completed, switch the states of the two four-way valves in ODU1 to the corresponding states of the two four-way valves in ODU2 in FIG. 2, switch the states of the two four-way valves in ODU2 to the corresponding states of the two four-way valves in ODU1 in FIG. 2, and then control ODU2 to operate in the heating mode and ODU1 to operate in the defrosting mode to defrost ODU1. The defrosting process is the same as the above embodiment, and in order to avoid repetition, it will not be described further here.

[0028] The stronger the evaporation capacity, which is the heat absorption capacity of the heat exchanger, the stronger the corresponding heat absorption capacity and the better the defrosting effect.

[0029] In this embodiment, when defrosting n outdoor unit units, by first defrosting k second outdoor unit units with weak evaporation capacity based on m first outdoor unit units with strong evaporation capacity, the defrosting effect of the k second outdoor unit units defrosted first is enhanced. When the defrosting of the k second outdoor unit units is completed, the evaporation capacity of the k second outdoor unit units is significantly improved. Subsequently, since the defrosting of the m first outdoor unit units is performed based on the k second outdoor unit units, the defrosting effect of the m first outdoor unit units defrosted next is also high, which is beneficial to improving the defrosting effect of the entire air-conditioning heat pump system.

[0030] As an alternative embodiment, each of the first outdoor unit units includes one first compressor and one first heat exchanger, and each of the second outdoor unit units includes one second compressor and one second heat exchanger. When the m first outdoor unit units operate in the heating mode and the k second outdoor unit units operate in the defrosting mode, the first compressor is in an operating state, the second compressor is in a non-operating state, the heat exchanger in the first outdoor unit unit forms an evaporator in the air-conditioning heat pump system, the heat exchanger in the second outdoor unit unit forms a condenser in the air-conditioning heat pump system, and in any one of the second outdoor unit units, the input end of the second heat exchanger communicates with the output end of each first compressor, and the output end of the second heat exchanger communicates with the input end of each first compressor. When the m first outdoor unit units operate in the defrosting mode and the k second outdoor unit units operate in the heating mode, the first compressor is in a non-operating state, the second compressor is in an operating state, the heat exchanger in the first outdoor unit unit forms a condenser in the air-conditioning heat pump system, the heat exchanger in the second outdoor unit unit forms an evaporator in the air-conditioning heat pump system, and in any one of the first outdoor unit units, the input end of the first heat exchanger communicates with the output end of each second compressor, and the output end of the first heat exchanger communicates with the input end of each second compressor.

[0031] In the related art, during the process of defrosting the second outdoor unit unit based on the first outdoor unit unit, both the compressor in the first outdoor unit unit and the compressor in the second outdoor unit unit are in an operating state, and the refrigerant discharged from the compressor in the first outdoor unit unit may directly enter the intake side of the compressor in the second outdoor unit unit. Therefore, there are problems such as the compression ratio of the compressor in the outdoor unit unit in the defrosting mode being too low and the exhaust pressure of the compressor in the outdoor unit unit in the heating mode being too low.

[0032] Refer to FIG. 2. In the embodiment shown in FIG. 2, the heat exchanger in ODU1 forms the first heat exchanger, the compressor in ODU1 forms the first compressor, the heat exchanger in ODU2 forms the second heat exchanger, and the compressor in ODU2 forms the second compressor.

[0033] In this embodiment, one four-way valve is added to each outdoor unit, that is, each outdoor unit includes two four-way valves to change the refrigerant flow, so that the refrigerant entering the second outdoor unit directly enters and condenses in the heat exchanger of the second outdoor unit without flowing through the compressor in the second outdoor unit, and by maintaining the closed state of the compressor in the second outdoor unit, problems such as too low compression ratio of the compressor in the outdoor unit in the defrost mode or too low exhaust pressure of the compressor in the outdoor unit in the heating mode are avoided.

[0034] In an alternative embodiment, each of the first outdoor unit units includes a first compressor and a first heat exchanger, and each of the second outdoor unit units includes a second compressor and a second heat exchanger. When the m first outdoor unit units operate in a heating mode and the k second outdoor unit units operate in a defrosting mode, the first compressor is in an operating state, the second compressor is in an operating state, the heat exchanger in the first outdoor unit forms an evaporator in the air conditioning heat pump system, the heat exchanger in the second outdoor unit forms a condenser in the air conditioning heat pump system, and in any second outdoor unit unit, the input end of the second compressor is connected to the output end of each first compressor, the output end of the second compressor is connected to the input end of the second heat exchanger, and the output end of the second heat exchanger is connected to the input end of each first compressor. When the m first outdoor unit units operate in a defrosting mode and the k second outdoor unit units operate in a heating mode, the first compressor is in an operating state, the second compressor is in an operating state, the heat exchanger in the first outdoor unit forms a condenser in the air conditioning heat pump system, the heat exchanger in the second outdoor unit forms an evaporator in the air conditioning heat pump system, and in any first outdoor unit unit, the input end of the first compressor is connected to the output end of each second compressor, the output end of the first compressor is connected to the input end of the first heat exchanger, and the output end of the first heat exchanger is connected to the input end of each second compressor.

[0035] Figure 3 is a schematic configuration diagram of an air-conditioning heat pump system provided by another embodiment of the present application. This air-conditioning heat pump system is different from the air-conditioning heat pump system shown in Figure 2 in the following aspects. That is, in the air-conditioning heat pump system of Figure 3, one four-way valve is reduced in each outdoor unit, that is, each outdoor unit only includes one four-way valve. Correspondingly, the connection relationship is also adaptively adjusted, and during the defrosting process, both the compressor in ODU1 and the compressor in ODU2 are in an operating state. Figure 3 is a flowchart of the defrosting process of ODU2 when ODU1 is in the heating mode and ODU2 is in the defrosting mode. As shown in Figure 3, a low-temperature and low-pressure gas refrigerant is stored in the storage tank of ODU1. The compressor in ODU1 consumes power to operate, sucks the refrigerant from the storage tank, and converts the refrigerant into a high-temperature and high-pressure gas. The high-temperature and high-pressure refrigerant flows in sequence through the E end of the four-way valve in ODU1, the D end of the four-way valve in ODU1, and the second pipeline in ODU1 and enters the second transmission pipeline. Since the second transmission pipeline communicates with the intake side of the compressor in ODU2, due to the suction action of the compressor in ODU2, the high-temperature and high-pressure refrigerant entering the second transmission pipeline flows through the second pipeline of ODU2, the E end of the four-way valve in ODU2, the S end of the four-way valve in ODU2, and the storage tank in ODU2 and enters the compressor in ODU2. The compressor in ODU2 outputs the high-temperature and high-pressure gas refrigerant to the heat exchanger in ODU2. At this time, the high-temperature and high-pressure gas refrigerant is condensed into a low-temperature and high-pressure liquid refrigerant in the heat exchanger in ODU2 serving as a condenser. During condensation, a large amount of heat is released from the refrigerant to heat the heat exchanger in ODU2 and defrost the heat exchanger in ODU2. The low-temperature and high-pressure refrigerant flowing out of the heat exchanger in ODU2 flows through the first pipeline in ODU2 and enters the first transmission pipeline. And during the process of flowing through the first pipeline in ODU2, the electronic expansion valve in the first pipeline in ODU2 reduces the pressure of the low-temperature and high-pressure liquid refrigerant and converts it into a low-temperature and low-pressure liquid refrigerant. After entering the first transmission pipeline, the low-temperature and low-pressure liquid refrigerant flows to the heat exchanger in ODU1 and returns to the storage tank in ODU1 through the heat exchanger.3, ODU1 is the first outdoor unit, ODU2 is the second outdoor unit, IDU1 is the first indoor unit, IDU2 is the second indoor unit, IDU3 is the third indoor unit, and IDU4 is the fourth indoor unit, where IDU1, IDU2, IDU3, and IDU4 collectively form an indoor unit. CSGL1 is the first transmission line, CSGL2 is the second transmission line, 1#Acc is the storage tank in ODU1, 1#YSJ is the compressor in ODU1, 1#HEX is the heat exchanger in ODU1, 1#STF is the four-way valve in ODU1, 1#EVO is the electronic expansion valve in ODU1, 1#GL1 is the first line in ODU1, and 1#GL2 is the second line in ODU1. 2#Acc indicates the storage tank in ODU2, 2#YSJ indicates the compressor in ODU2, 2#HEX indicates the heat exchanger in ODU2, 2#STF indicates the four-way valve in ODU2, 2#EVO indicates the electronic expansion valve in ODU2, 2#GL1 indicates the first pipeline in ODU2, and 2#GL2 indicates the second pipeline in ODU2.

[0036] As an optional embodiment, when the m first outdoor unit units operate in a heating mode and the k second outdoor unit units operate in a defrost mode, the method further includes controlling the frequency of the first compressor based on the discharge pressure of the first compressor and controlling the frequency of the second compressor based on a compression ratio of the second compressor. The compression ratio ε2 of the second compressor is Pd2 / Ps2. Pd2 is the discharge pressure of the second compressor, and Ps2 is the intake pressure of the second compressor. When the m first outdoor unit units operate in a defrost mode and the k second outdoor unit units operate in a heating mode, the method further includes controlling the frequency of the first compressor based on the compression ratio of the first compressor and controlling the frequency of the second compressor based on the discharge pressure of the second compressor. The compression ratio ε1 of the first compressor is Pd1 / Ps1. Pd1 is the discharge pressure of the first compressor, and Ps1 is the intake pressure of the first compressor.

[0037] In the embodiment shown in FIG. 3, since both the first compressor and the second compressor are in an operating state, there are problems such as the compression ratio of the compressor in the outdoor unit in the defrost mode being too low, or the exhaust pressure of the compressor in the outdoor unit in the heating mode being too low.

[0038] Here, controlling the frequency of the first compressor based on the exhaust pressure of the first compressor and controlling the frequency of the second compressor based on the compression ratio of the second compressor includes: when the exhaust pressure of the first compressor is equal to or higher than a first threshold value, controlling the frequency of the first compressor to decrease; when the exhaust pressure of the first compressor is less than the first threshold value, controlling the frequency of the first compressor to increase; when the compression ratio of the second compressor is equal to or higher than a second threshold value, setting the frequency of the second compressor to a first frequency value that is a (a > 0) times the frequency of the first compressor; and when the compression ratio of the second compressor is less than the second threshold value, setting the frequency of the second compressor to a second frequency value that is b (b > a) times the frequency of the first compressor.

[0039] Specifically, the first threshold value is set according to actual needs. When the exhaust pressure of the first compressor is equal to or higher than the first threshold value, by controlling the frequency of the first compressor to decrease, and when the exhaust pressure of the first compressor is less than the first threshold value, by controlling the frequency of the first compressor to increase, it is ensured that the exhaust pressure of the first compressor in the heating mode is always near the first threshold value, thus avoiding the problem that the exhaust pressure of the first compressor is too low.

[0040] Correspondingly, the second threshold value is also set according to actual needs. When the frequency of the second compressor drops below the second threshold value, by switching the frequency of the second compressor from the first frequency value to the second frequency value, that is, increasing the frequency value of the second compressor, Pd2 and Pd2 / Ps2 also increase accordingly, thus avoiding the problem that the compression ratio ε2 of the second compressor is too low.

[0041] Controlling the frequency of the first compressor based on the compression ratio of the first compressor and controlling the frequency of the second compressor based on the discharge pressure of the second compressor includes, when the compression ratio of the first compressor is greater than or equal to the second threshold, setting the frequency of the first compressor to a third frequency value that is a times the frequency of the second compressor, and when the compression ratio of the first compressor is less than the second threshold, setting the frequency of the first compressor to a fourth frequency value that is b times the frequency of the second compressor; and when the discharge pressure of the second compressor is greater than or equal to the first threshold, controlling the frequency of the second compressor to decrease, and when the discharge pressure of the second compressor is less than the second threshold, controlling the frequency of the second compressor to increase.

[0042] FIG. 4 is a flowchart for adjusting the compressor frequency F2 of ODU2 during the defrosting process of ODU1. Here, Pd2 is the discharge pressure of the second compressor in ODU2, and G is the first threshold. FIG. 5 is a flowchart for adjusting the compressor frequency F2 in ODU2 during the defrosting process of ODU2. Here, Pd2 is the discharge pressure of the second compressor in ODU2, Ps2 is the suction pressure of the second compressor in ODU2, ε2 is the compression ratio of the second compressor, and H is the second threshold. Correspondingly, the frequency of ODU1 is adjusted in the same manner.

[0043] Refer to the following table. This table is a comparison table of the operating parameters of the compressor in the defrosting process between the technical aspect of the present application and the technical aspect of the related art. As is clear from the table, compared with the related art, the technical aspect of the present application can effectively increase the compression ratio of the compressor in the outdoor unit in the defrosting mode and effectively increase the discharge pressure of the compressor in the outdoor unit in the heating mode.

[0044]

Table 1

[0045] In this embodiment, when the m first outdoor unit units operate in the heating mode and the k second outdoor unit units operate in the defrosting mode, the frequency of the first compressor is controlled based on the compression ratio of the first compressor, and the frequency of the second compressor is controlled based on the discharge pressure of the second compressor, so as to avoid problems such as the compression ratio of the compressor in the outdoor unit unit in the defrosting mode being too low and the discharge pressure of the compressor in the outdoor unit unit in the heating mode being too low, which occur during the defrosting process of the second outdoor unit unit. Correspondingly, when the m first outdoor unit units operate in the defrosting mode and the k second outdoor unit units operate in the heating mode, the frequency of the first compressor is controlled based on the compression ratio of the first compressor, and the frequency of the second compressor is controlled based on the discharge pressure of the second compressor, so as to avoid problems such as the compression ratio of the compressor in the outdoor unit unit in the defrosting mode being too low and the discharge pressure of the compressor in the outdoor unit unit in the heating mode being too low, which occur during the defrosting process of the first outdoor unit unit.

[0046] As an alternative embodiment, the evaporation capacity parameter is determined based on the capacity parameter of the outdoor unit unit, the frost thickness value of the outdoor unit unit, or whether the outdoor unit unit meets the defrosting conditions. Here, the evaporation capacity parameter and the capacity parameter show a positive correlation, and the evaporation capacity parameter and the frost thickness value show a negative correlation.

[0047] Here, the capacity parameter of the outdoor unit, which is the number of outdoor units, may be, for example, 1, 2, 3, etc. The frosting thickness value is the frosting thickness on the surface of the outdoor unit. Since the frosting thickness value and the power ratio of the outdoor unit show a positive correlation, and the power ratio is the ratio of the peak power of the fan in the outdoor unit to the operating power of the fan, the frosting thickness value of the outdoor unit can be represented by the power ratio of the outdoor unit. The peak power may be the peak power during the previous startup of the fan, and the operating power may be the real-time power of the fan. In the related art, usually, when the thickness of the frost layer of the outdoor unit is equal to or greater than a specific threshold, it is determined that the outdoor unit meets the defrosting condition, and when the thickness of the frost layer of the outdoor unit is less than the specific threshold, it is determined that the outdoor unit does not meet the defrosting condition. Therefore, by setting the evaporation capacity parameter of the outdoor unit that meets the defrosting condition to 1 and the evaporation capacity parameter of the outdoor unit that does not meet the defrosting condition to 0, the evaporation capacity parameter can be determined according to whether the outdoor unit meets the defrosting condition.

[0048] Referring to FIG. 9, in some embodiments of the present application, the air-conditioning heat pump system includes two outdoor units, ODU1 and ODU2. In the alternating defrosting mode, the capacity parameters C1 of ODU1 and C2 of ODU2 are obtained. When C1≥C2, first, ODU2 is defrosted, and after the defrosting of ODU2 is completed, ODU1 is further defrosted. When C1<C2, first, ODU1 is defrosted, and after the defrosting of ODU1 is completed, ODU2 is further defrosted.

[0049] In some embodiments of the present application, the air-conditioning heat pump system includes two outdoor units, ODU1 and ODU2. In the alternating defrosting mode, the evaporation capacity parameters of ODU1 and ODU2 are obtained according to whether the defrosting condition is met. When the evaporation capacity parameter of ODU1 is 0 and the evaporation capacity parameter of ODU2 is 1, first, ODU1 is defrosted, and after the defrosting of ODU1 is completed, ODU2 is further defrosted.

[0050] In another embodiment of the present application, an air conditioning heat pump system includes four outdoor unit units ODU1, ODU2, ODU3, and ODU4, and in the alternate defrost mode, the evaporation capacity parameters of ODU1, ODU2, ODU3, and ODU4 are obtained depending on whether the defrosting conditions are met. If the evaporation capacity parameters of ODU1 and ODU2 are all 0 and the evaporation capacity parameters of ODU3 and ODU4 are all 1, ODU1 and ODU2 are defrosted first, and after defrosting of ODU1 and ODU2 is completed, ODU3 and ODU4 are further defrosted.

[0051] See Fig. 10. In some embodiments of the present application, an air conditioning heat pump system includes two outdoor units, ODU1 and ODU2, and in the alternate defrosting mode, a power ratio λ1 of ODU1 and a power ratio λ2 of ODU2 are obtained, and if λ1 ≥ λ2, ODU2 is defrosted first, and after defrosting of ODU2 is completed, ODU1 is defrosted again. If λ1 < λ2, ODU1 is defrosted first, and after defrosting of ODU1 is completed, ODU2 is defrosted again.

[0052] Also, refer to Figure 11. In some embodiments of the present application, it may be set so that defrosting is not performed when the power ratio of the outdoor unit is equal to or less than a fourth threshold C, and defrosting is performed when the power ratio of the outdoor unit is greater than C.

[0053] See Figure 6. In some embodiments of the present application, the evaporation capacity parameter may simultaneously include the capacity parameter of the outdoor unit and the frost thickness value of the outdoor unit. When C1 ≥ C2, if λ1 ≤ λ2, defrost ODU2 first, and then defrost ODU1 after the defrosting of ODU2 is completed. C1 <C2の場合、まずODU1を除霜し、ODU1の除霜が完了した後、更にODU2を除霜する。当λ1<λ2の場合、まずODU1を除霜し、ODU1の除霜が完了した後、更にODU2を除霜する。

[0054] As an alternative embodiment, when the air-conditioning heat pump system is in the alternate defrost mode, before obtaining the evaporation capacity information of the n outdoor unit units, the method further includes a power ratio that is the ratio of the peak power of the fan in the outdoor unit unit to the operating power of the fan, obtaining the power ratio of each of the n outdoor unit units among the n outdoor unit units to obtain n power ratios, and when at least one of the n power ratios is greater than or equal to a third threshold, controlling the air-conditioning heat pump system to shift to a normal defrost mode in which the heat exchanger in the n outdoor unit units forms a condenser and the heat exchanger in the indoor unit unit forms an evaporator, and when all of the n power ratios are less than the third threshold, controlling the air-conditioning heat pump system to shift to the alternate defrost mode.

[0055] Referring to FIG. 7, in some embodiments of the present application, the air-conditioning heat pump system includes two outdoor unit units, ODU1 and ODU2, and the defrost mode determination process includes the following steps. Obtain the peak power P1 at the previous defrost start of ODU1 and the peak power P2 at the previous defrost start of ODU2. During the heating operation, record the maximum fan power Pa of ODU1 and the maximum fan power Pb of ODU2 during the current operation every t hours. Calculate the power ratios of the two outdoor unit units. λ1 = Pa / P1, λ2 = Pb / P2. When a defrost signal is received, determine the relative magnitudes of λ1, λ2 and the third threshold E. If λ1 ≧ E or λ2 ≧ E, shift to the normal defrost mode; otherwise, shift to the alternate defrost mode.

[0056] Here, when the power ratio of the outdoor unit is equal to or greater than the third threshold value, it indicates that the thickness of the frost on the surface of the outdoor unit is large. In this case, there is a problem that defrosting cannot be completed in the alternating defrosting mode. Based on this, when the power ratio of at least one outdoor unit is equal to or greater than the third threshold value, the normal defrosting mode is adopted for defrosting. In the normal defrosting mode, all outdoor units are in the defrosting mode, and the compressors in all outdoor units are in the operating state, which is advantageous for improving the defrosting effect. In any case, when all of the n power ratios are less than the third threshold value, if the air-conditioning heat pump system is controlled to shift to the alternating defrosting mode, the defrosting effect can be guaranteed and the time required for the defrosting operation can be shortened.

[0057] In the embodiment described in FIG. 8, when the air-conditioning heat pump system is in the heating mode, the outdoor heat exchangers of ODU1 and ODU2 are in the evaporator state, with low temperature and pressure, and all indoor units are in the condenser state, with high temperature and pressure. At this time, the compressors of the outdoor units ODU1 and ODU2 are in parallel.

[0058] In the embodiment shown in FIG. 8, when the air-conditioning heat pump system is in the normal defrosting mode, the outdoor heat exchangers of ODU1 and ODU2 both switch to the condenser state, and all indoor units are in the evaporator state, with low temperature and pressure.

[0059] In the embodiment described in FIG. 8, when the air-conditioning heat pump system is in the alternating defrosting mode, ODU1 and ODU2 perform defrosting alternately, and one heat exchanger of the outdoor unit is maintained in the evaporator state. In this case, the indoor unit is in the medium-pressure state and has a high temperature. When the frost layers on the heat exchangers of ODU1 and ODU2 are relatively thick, the evaporation capacity of the heat exchangers is poor, and it is likely that the defrosting cannot be thoroughly performed by alternating defrosting, which affects the comfort and reliability of the subsequent operation of the air conditioner. At this time, the compressors of the outdoor units ODU1 and ODU2 are in series. Since the refrigerant on the exhaust side of the compressor of the outdoor unit for heating directly enters the intake side of the compressor of the outdoor unit for defrosting, the compressor of the outdoor unit for defrosting is very likely to have the problem that the compression ratio is too low, and at the same time, the compressor of the outdoor unit for heating is also very likely to have the problem that the exhaust pressure is too low.

[0060] Here, when ODU1 is in the heating mode and ODU2 is in the defrosting mode, the frequency of the compressor of ODU1 is controlled by the exhaust pressure of the compressor of ODU1, and the frequency of the compressor of ODU2 is controlled by the compression ratio of the compressor of ODU2. When ODU1 is in the defrosting mode and ODU2 is in the heating mode, the frequency of the compressor of ODU2 is controlled by the exhaust pressure of the compressor of ODU2, and the frequency of the compressor of ODU1 is controlled by the compression ratio of the compressor of ODU1.

[0061] Frost formation on the unit causes an increase in the fan power at the same rotational speed. First, the thickness of the frost layer on the unit is judged by the power increase ratio, and it is judged whether to shift to alternating defrosting to ensure thorough defrosting. At the same time, the priority order of defrosting of the units is judged, and first, the outdoor unit with a small evaporation capacity is defrosted to ensure that the outdoor unit with a large evaporation capacity has a strong evaporation capacity and the outdoor unit with a small evaporation capacity can be thoroughly defrosted. When the outdoor unit with a small evaporation capacity is thoroughly defrosted, its evaporation capacity becomes strong, and then the outdoor unit with a large evaporation capacity is defrosted to ensure that all outdoor units can be thoroughly defrosted.

[0062] As an alternative embodiment, when n is equal to 2, the m first outdoor unit units include one outdoor unit unit with the largest value of the evaporation capacity parameter among the n outdoor unit units, and the k second outdoor unit units include one outdoor unit unit with the smallest value of the evaporation capacity parameter among the n outdoor unit units. When n is equal to 3, the m first outdoor unit units include two outdoor unit units with the smaller values of the evaporation capacity parameter among the n outdoor unit units, and the k second outdoor unit units include one outdoor unit unit with the largest value of the evaporation capacity parameter among the n outdoor unit units. When n is equal to 4, the m first outdoor unit units include two outdoor unit units with the larger values of the evaporation capacity parameter among the n outdoor unit units, and the k second outdoor unit units include two outdoor unit units with the smaller values of the evaporation capacity parameter among the n outdoor unit units. For example, when the capacity parameters of the ODU1, ODU2, ODU3, and ODU4 increase sequentially, ODU1 and ODU2 are used as the m first outdoor unit units, and ODU3 and ODU4 are used as the k second outdoor unit units. Also, for example, when the capacity parameters of the ODU1, ODU2, ODU3, and ODU4 decrease sequentially, ODU3 and ODU4 are used as the m first outdoor unit units, and ODU1 and ODU2 are used as the k second outdoor unit units.

[0063] Specifically, as shown in FIG. 8, when n is equal to 2, the defrosting priority of ODU1 and ODU2 can be determined based on the flow in FIG. 9 or FIG. 10. As shown in FIG. 12, when n is equal to 3, the defrosting priority of ODU1 and ODU2 can be determined based on the flow in FIG. 13. As shown in FIG. 14, when n is equal to 4, the defrosting priority of ODU1 and ODU2 can be determined based on the flow in FIG. 14.

[0064] FIG. 8 is a schematic diagram of the refrigerant flow in the defrosting process of ODU1 based on ODU2 when n is equal to 2. In this case, ODU2 is in the heating mode and ODU1 is in the defrosting mode.

[0065] FIG. 12 is a flowchart of defrosting of ODU1 based on ODU2 and ODU3 when n is equal to 3. In this case, ODU2 and ODU3 are in the heating mode, and ODU1 is in the defrosting mode.

[0066] FIG. 14 is a flowchart of defrosting of ODU1 and ODU2 based on ODU3 and ODU4 when n is equal to 4. In this case, ODU3 and ODU4 are in the heating mode, and ODU1 and ODU2 are in the defrosting mode.

[0067] Refer to FIG. 16. FIG. 16 is a flowchart of a control method for an air-conditioning heat pump system provided by an embodiment of the present application. The air-conditioning heat pump system includes an indoor unit and n outdoor units. The n is an integer greater than 1. The control method includes step 1601 of obtaining capacity parameters of the n outdoor units when the air-conditioning heat pump system is in the alternate defrosting mode, step 1602 of dividing the n outdoor units into m (m is an integer greater than 0) first outdoor units and k (k is an integer greater than 0 and the sum of m and k is n) second outdoor units based on the capacity parameters, where the sum of the capacity parameters of the k second outdoor units is less than or equal to the sum of the capacity parameters of the m first outdoor units, step 1603 of controlling the m first outdoor units to operate in the heating mode and controlling the k second outdoor units to operate in the defrosting mode, and step 1604 of controlling the m first outdoor units to operate in the defrosting mode and controlling the k second outdoor units to operate in the heating mode after the defrosting of the k second outdoor units is completed.

[0068] This embodiment is a control method for an air-conditioning heat pump system when the evaporation capacity parameter is a capacity parameter. The specific implementation process is the same as that of the above embodiment, and all processes in the above embodiment can be realized, and moreover, it has all the beneficial effects in the above embodiment.

[0069] Refer to FIG. 17. FIG. 17 is a flowchart of a control method for an air-conditioning heat pump system provided according to an embodiment of the present application. The air-conditioning heat pump system includes an indoor unit and n outdoor units. The n is an integer greater than 1. The control method includes: step 1701 of obtaining the frosting thickness values of the n outdoor units when the air-conditioning heat pump system is in the alternating defrosting mode; step 1702 of dividing the n outdoor units into m (m is an integer greater than 0) first outdoor units and k (k is an integer greater than 0, and the sum of m and k is n) second outdoor units based on the frosting thickness values, where the sum of the frosting thickness values of the k second outdoor units is greater than or equal to the sum of the frosting thickness values of the m first outdoor units; step 1703 of controlling the m first outdoor units to operate in the heating mode and controlling the k second outdoor units to operate in the defrosting mode; and step 1704 of, after the defrosting of the k second outdoor units is completed, controlling the m first outdoor units to operate in the defrosting mode and controlling the k second outdoor units to operate in the heating mode.

[0070] This embodiment is a control method for an air-conditioning heat pump system when the evaporation capacity parameter is the frosting thickness value. Its specific implementation process is the same as that of the above embodiment, and all processes in the above embodiment can be realized, and moreover, it has all the beneficial effects in the above embodiment.

[0071] Refer to FIG. 18. FIG. 18 is a flowchart of a control method for an air-conditioning heat pump system provided according to an embodiment of the present application. The air-conditioning heat pump system includes an indoor unit and n outdoor units. The n is an integer greater than 1. The control method includes step 1801 of determining whether each of the n outdoor units satisfies a defrosting condition when the air-conditioning heat pump system is in an alternating defrosting mode; step 1802 of dividing the n outdoor units into m (m is an integer greater than 0) first outdoor units that satisfy the defrosting condition and k (k is an integer greater than 0, and the sum of the m and the k is the n) second outdoor units that do not satisfy the defrosting condition among the n outdoor units; step 1803 of controlling the m first outdoor units to operate in a heating mode and controlling the k second outdoor units to operate in a defrosting mode; and step 1804 of, after the defrosting of the k second outdoor units is completed, controlling the m first outdoor units to operate in a defrosting mode and controlling the k second outdoor units to operate in a heating mode.

[0072] In the related art, usually, when the thickness of the frost layer of an outdoor unit is greater than or equal to a specific threshold, it is determined that the outdoor unit satisfies the defrosting condition, and when the thickness of the frost layer of the outdoor unit is less than the specific threshold, it is determined that the outdoor unit does not satisfy the defrosting condition. Therefore, by setting the evaporation capacity parameter of the outdoor unit that satisfies the defrosting condition to 1 and the evaporation capacity parameter of the outdoor unit that does not satisfy the defrosting condition to 0, the evaporation capacity parameter can be determined according to whether the outdoor unit satisfies the defrosting condition.

[0073] In some embodiments of the present application, the air-conditioning heat pump system includes two outdoor unit units, ODU1 and ODU2. In the alternating defrosting mode, the evaporation capacity parameters of ODU1 and ODU2 are obtained according to whether the defrosting conditions are met. When the evaporation capacity parameter of ODU1 is 0 and the evaporation capacity parameter of ODU2 is 1, first defrost ODU1, and after the defrosting of ODU1 is completed, further defrost ODU2.

[0074] In other embodiments of the present application, the air-conditioning heat pump system includes four outdoor unit units, ODU1, ODU2, ODU3, and ODU4. In the alternating defrosting mode, the evaporation capacity parameters of ODU1, ODU2, ODU3, and ODU4 are obtained according to whether the defrosting conditions are met. When the evaporation capacity parameters of both ODU1 and ODU2 are 0 and the evaporation capacity parameters of both ODU3 and ODU4 are 1, first defrost ODU1 and ODU2, and after the defrosting of ODU1 and ODU2 is completed, further defrost ODU3 and ODU4.

[0075] This embodiment corresponds to a control method of an air-conditioning heat pump system corresponding to the embodiment in which the outdoor unit determines the evaporation capacity parameter according to whether the defrosting condition is met in the above embodiment. The specific implementation process is the same as that of the above embodiment, and all processes in the above embodiment can be realized, and moreover, all beneficial effects in the above embodiment are achieved.

[0076] Refer to FIG. 2. FIG. 2 is a schematic configuration diagram of an air-conditioning heat pump system provided by an embodiment of the present application. The air-conditioning heat pump system includes a controller, an indoor unit, a first transmission pipeline, a second transmission pipeline, and n (n is an integer greater than 1) outdoor units, and the indoor unit and the n outdoor units are each electrically connected to the controller. Each of the outdoor units includes a storage tank, a compressor, a heat exchanger, a first four-way valve, a second four-way valve, an electronic expansion valve, a first pipeline, and a second pipeline. And in each outdoor unit, the output end of the storage tank and the input end of the compressor are connected through a pipeline, the output end of the compressor and the E end of the first four-way valve are connected through a pipeline, the D end of the first four-way valve and the D end of the second four-way valve are connected through a pipeline, the C end of the second four-way valve and the input end of the heat exchanger are connected through a pipeline, the output end of the heat exchanger is connected to the first end of the first pipeline, the electronic expansion valve is provided in the first pipeline, the second end of the first pipeline forms the first external port of the outdoor unit, the S end of the second four-way valve and the C end of the first four-way valve are connected through a pipeline, the S end of the first four-way valve and the input end of the storage tank are connected through a pipeline, the E end of the second four-way valve is connected to the first end of the second pipeline, and the second end of the second pipeline forms the second external port of the outdoor unit. The first transmission pipeline includes one input end connected to the output end of the indoor unit and n first connection ends connected in one-to-one correspondence to the n first external ports of the n outdoor units. The second transmission pipeline includes one output end connected to the input end of the indoor unit and n second connection ends connected in one-to-one correspondence to the n second external ports of the n outdoor units.

[0077] As an alternative embodiment, when m of the n outdoor unit units are in the heating mode and k of the n outdoor unit units are in the defrosting mode, the controller controls the D end and the E end of the first four-way valve in the first outdoor unit unit to be electrically connected, the S end and the C end of the first four-way valve in the first outdoor unit unit to be electrically connected, the D end and the E end of the second four-way valve in the first outdoor unit unit to be electrically connected, the S end and the C end of the second four-way valve in the first outdoor unit unit to be electrically connected, the D end and the C end of the first four-way valve in the second outdoor unit unit to be electrically connected, the S end and the E end of the first four-way valve in the first outdoor unit unit to be electrically connected, the D end and the C end of the second four-way valve in the second outdoor unit unit to be electrically connected, and the S end and the E end of the second four-way valve in the second outdoor unit unit to be electrically connected, where m and k are each an integer greater than 0, and the sum of m and k is n. When m of the n outdoor unit units are in the defrosting mode and k of the n outdoor unit units are in the heating mode, the controller controls the D end and the C end of the first four-way valve in the first outdoor unit unit to be electrically connected, the S end and the E end of the first four-way valve in the first outdoor unit unit to be electrically connected, the D end and the C end of the second four-way valve in the first outdoor unit unit to be electrically connected, the S end and the E end of the second four-way valve in the first outdoor unit unit to be electrically connected, the D end and the E end of the first four-way valve in the second outdoor unit unit to be electrically connected, the S end and the C end of the first four-way valve in the first outdoor unit unit to be electrically connected, the D end and the E end of the second four-way valve in the second outdoor unit unit to be electrically connected, and the S end and the C end of the second four-way valve in the second outdoor unit unit to be electrically connected.

[0078] The air-conditioning heat pump system provided by this embodiment is the air-conditioning heat pump system corresponding to the above-described embodiment, and the controller in the air-conditioning heat pump system can implement each process of the control method in the above-described embodiment and has the same beneficial effects. To avoid repetition, no further description is provided here.

[0079] The embodiments of the present application have been described above with reference to the accompanying drawings. However, the present application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can take many forms within the protection scope of the present application without departing from the spirit of the present application and the scope protected by the claims under the inspiration of the present application.

Claims

1. In a method for controlling an air-conditioning heat pump system, the air-conditioning heat pump system includes an indoor unit and n (n is an integer greater than 1) outdoor units, the control method includes: when the air-conditioning heat pump system is in an alternating defrosting mode, obtaining evaporation capacity information of the n outdoor units, which is an evaporation capacity parameter used to represent the evaporation capacity during the operation process of the corresponding outdoor unit, and includes n evaporation capacity parameters corresponding one-to-one to the n outdoor units; based on the evaporation capacity information, dividing the n outdoor units into m (m is an integer greater than 0) first outdoor units and k (k is an integer greater than 0, and the sum of m and k is n) second outdoor units, where the sum of the evaporation capacity parameters of the k second outdoor units is less than or equal to the sum of the evaporation capacity parameters of the m first outdoor units; controlling the m first outdoor units to operate in a heating mode and controlling the k second outdoor units to operate in a defrosting mode; after the defrosting of the k second outdoor units is completed, controlling the m first outdoor units to operate in a defrosting mode and controlling the k second outdoor units to operate in a heating mode.

2. In the control method according to Claim 1, each of the first outdoor units includes one first compressor and one first heat exchanger, each of the second outdoor units includes one second compressor and one second heat exchanger, when the m first outdoor units operate in a heating mode and the k second outdoor units operate in a defrosting mode, the first compressor is in an operating state, the second compressor is in a non-operating state, the heat exchanger in the first outdoor unit forms the evaporator in the air-conditioning heat pump system, the heat exchanger in the second outdoor unit forms the condenser in the air-conditioning heat pump system, and in any one of the second outdoor units, the input end of the second heat exchanger communicates with the output end of each first compressor, and the output end of the second heat exchanger communicates with the input end of each first compressor. When the m first outdoor unit units operate in the defrosting mode and the k second outdoor unit units operate in the heating mode, the first compressor is in a non-operating state, the second compressor is in an operating state, the heat exchanger in the first outdoor unit unit forms the condenser in the air-conditioning heat pump system, the heat exchanger in the second outdoor unit unit forms the evaporator in the air-conditioning heat pump system, and in any one of the first outdoor unit units, the input end of the first heat exchanger communicates with the output end of each second compressor, and the output end of the first heat exchanger communicates with the input end of each second compressor. A control method characterized by this.

3. In the control method according to Claim 1, Each of the first outdoor unit units includes one first compressor and one first heat exchanger, Each of the second outdoor unit units includes one second compressor and one second heat exchanger, When the m first outdoor unit units operate in the heating mode and the k second outdoor unit units operate in the defrosting mode, the first compressor is in an operating state, the second compressor is in an operating state, the heat exchanger in the first outdoor unit unit forms the evaporator in the air-conditioning heat pump system, the heat exchanger in the second outdoor unit unit forms the condenser in the air-conditioning heat pump system, and in any one of the second outdoor unit units, the input end of the second compressor communicates with the output end of each first compressor, the output end of the second compressor communicates with the input end of the second heat exchanger, and the output end of the second heat exchanger communicates with the input end of each first compressor. When the m first outdoor unit units operate in the defrosting mode and the k second outdoor unit units operate in the heating mode, the first compressor is in an operating state, the second compressor is in an operating state, the heat exchanger in the first outdoor unit unit forms the condenser in the air-conditioning heat pump system, the heat exchanger in the second outdoor unit unit forms the evaporator in the air-conditioning heat pump system, and in any one of the first outdoor unit units, the input end of the first compressor communicates with the output end of each second compressor, the output end of the first compressor communicates with the input end of the first heat exchanger, and the output end of the first heat exchanger communicates with the input end of each second compressor. A control method characterized by this.

4. In the control method according to Claim 3, When the m first outdoor unit units operate in the heating mode and the k second outdoor unit units operate in the defrosting mode, further, controlling the frequency of the first compressor based on the discharge pressure of the first compressor and controlling the frequency of the second compressor based on the compression ratio of the second compressor, When the m first outdoor unit units operate in the defrosting mode and the k second outdoor unit units operate in the heating mode, further, controlling the frequency of the first compressor based on the compression ratio of the first compressor and controlling the frequency of the second compressor based on the discharge pressure of the second compressor, characterized by the control method.

5. In the control method according to claim 4, Controlling the frequency of the first compressor based on the discharge pressure of the first compressor and controlling the frequency of the second compressor based on the compression ratio of the second compressor includes: When the discharge pressure of the first compressor is equal to or greater than a first threshold value, controlling the frequency of the first compressor to decrease, and when the discharge pressure of the first compressor is less than the first threshold value, controlling the frequency of the first compressor to increase; When the compression ratio of the second compressor is equal to or greater than a second threshold value, setting the frequency of the second compressor to a first frequency value that is a times the frequency of the first compressor, and when the compression ratio of the second compressor is less than the second threshold value, setting the frequency of the second compressor to a second frequency value that is b (b > a) times the frequency of the first compressor; Controlling the frequency of the first compressor based on the compression ratio of the first compressor and controlling the frequency of the second compressor based on the discharge pressure of the second compressor includes: When the compression ratio of the first compressor is equal to or greater than the second threshold value, setting the frequency of the first compressor to a third frequency value that is a times the frequency of the second compressor, and when the compression ratio of the first compressor is less than the second threshold value, setting the frequency of the first compressor to a fourth frequency value that is b times the frequency of the second compressor; When the discharge pressure of the second compressor is equal to or greater than the first threshold value, controlling the frequency of the second compressor to decrease, and when the discharge pressure of the second compressor is less than the second threshold value, controlling the frequency of the second compressor to increase, characterized by the control method.

6. In the control method according to claim 1, The evaporation capacity parameter is determined based on the capacity parameter of the outdoor unit, the frosting thickness value of the outdoor unit, or whether the outdoor unit satisfies the defrosting condition. Here, the control method is characterized in that the evaporation capacity parameter and the capacity parameter show a positive correlation, and the evaporation capacity parameter and the frosting thickness value show a negative correlation.

7. In the control method according to claim 6, The control method is characterized in that the frosting thickness value and the power ratio of the outdoor unit, which is the ratio of the peak power of the fan in the outdoor unit to the operating power of the fan, show a positive correlation.

8. In the control method according to claim 1, When the air-conditioning heat pump system is in the alternate defrosting mode, before acquiring the evaporation capacity information of the n outdoor units, further, Obtaining the power ratio, which is the ratio of the peak power of the fan in the outdoor unit to the operating power of the fan, and obtaining the power ratios of each of the n outdoor units among the n outdoor units to obtain n power ratios; When at least one of the n power ratios is greater than or equal to a third threshold value, controlling the air-conditioning heat pump system to shift to a normal defrosting mode in which the heat exchanger in the n outdoor units forms a condenser and the heat exchanger in the indoor unit forms an evaporator; When all of the n power ratios are less than the third threshold value, controlling the air-conditioning heat pump system to shift to the alternate defrosting mode.

9. In the control method according to claim 1, When n is equal to 2, the m first outdoor units include one outdoor unit with the largest value of the evaporation capacity parameter among the n outdoor units, and the k second outdoor units include one outdoor unit with the smallest value of the evaporation capacity parameter among the n outdoor units. When n is equal to 3, the m first outdoor units include two outdoor units with smaller values of the evaporation capacity parameter among the n outdoor units, and the k second outdoor units include one outdoor unit with the largest value of the evaporation capacity parameter among the n outdoor units. When n is equal to 4, the m first outdoor unit units include two outdoor unit units with larger evaporation capacity parameter values among the n outdoor unit units, and the k second outdoor unit units include two outdoor unit units with smaller evaporation capacity parameter values among the n outdoor unit units. A control method characterized by this.

10. In a control method for an air conditioning heat pump system, the air conditioning heat pump system includes an indoor unit unit and n (n is an integer greater than 1) outdoor unit units, the control method is as follows: when the air conditioning heat pump system is in the alternating defrost mode, obtain the capacity parameter of the n outdoor unit units; based on the capacity parameter, divide the n outdoor unit units into m (m is an integer greater than 0) first outdoor unit units and k (k is an integer greater than 0, and the sum of m and k is n) second outdoor unit units, where the sum of the capacity parameters of the k second outdoor unit units is less than or equal to the sum of the capacity parameters of the m first outdoor unit units; control the m first outdoor unit units to operate in the heating mode and control the k second outdoor unit units to operate in the defrost mode; after the defrosting of the k second outdoor unit units is completed, control the m first outdoor unit units to operate in the defrost mode and control the k second outdoor unit units to operate in the heating mode. A control method characterized by including this.

11. In a control method for an air conditioning heat pump system, the air conditioning heat pump system includes an indoor unit unit and n (n is an integer greater than 1) outdoor unit units, the control method is as follows: when the air conditioning heat pump system is in the alternating defrost mode, obtain the frost thickness value of the n outdoor unit units; based on the frost thickness value, divide the n outdoor unit units into m (m is an integer greater than 0) first outdoor unit units and k (k is an integer greater than 0, and the sum of m and K is n) second outdoor unit units, where the sum of the frost thickness values of the k second outdoor unit units is greater than or equal to the sum of the frost thickness values of the m first outdoor unit units; control the m first outdoor unit units to operate in the heating mode and control the k second outdoor unit units to operate in the defrost mode; After the defrosting of the k second outdoor unit units is completed, controlling the m first outdoor unit units to operate in a defrosting mode and controlling the k second outdoor unit units to operate in a heating mode. A control method characterized by including this.

12. In a control method of an air-conditioning heat pump system, The air-conditioning heat pump system includes an indoor unit unit and n (n is an integer greater than 1) outdoor unit units, The control method is as follows: When the air-conditioning heat pump system is in an alternating defrosting mode, determining whether each of the n outdoor unit units satisfies a defrosting condition; Dividing the n outdoor unit units into m (m is an integer greater than 0) first outdoor unit units among the n outdoor unit units that satisfy the defrosting condition and k (k is an integer greater than 0, and the sum of m and k is n) second outdoor unit units among the n outdoor unit units that do not satisfy the defrosting condition; Controlling the m first outdoor unit units to operate in a heating mode and controlling the k second outdoor unit units to operate in a defrosting mode; After the defrosting of the k second outdoor unit units is completed, controlling the m first outdoor unit units to operate in a defrosting mode and controlling the k second outdoor unit units to operate in a heating mode. A control method characterized by including this.

13. An air-conditioning heat pump system, Including a controller, an indoor unit unit, a first transmission pipeline, a second transmission pipeline, and n (n is an integer greater than 1) outdoor unit units, The indoor unit unit and the n outdoor unit units are each electrically connected to the controller, Each of the outdoor unit units includes a storage tank, a compressor, a heat exchanger, a first four-way valve, a second four-way valve, an electronic expansion valve, a first pipeline, and a second pipeline. And in each outdoor unit unit, the output end of the storage tank and the input end of the compressor are connected through a pipeline, the output end of the compressor and the E end of the first four-way valve are connected through a pipeline, the D end of the first four-way valve and the D end of the second four-way valve are connected through a pipeline, the C end of the second four-way valve and the input end of the heat exchanger are connected through a pipeline, the output end of the heat exchanger is connected to the first end of the first pipeline, the electronic expansion valve is provided in the first pipeline, the second end of the first pipeline forms the first external port of the outdoor unit unit, the S end of the second four-way valve and the C end of the first four-way valve are connected through a pipeline, the S end of the first four-way valve and the input end of the storage tank are connected through a pipeline, the E end of the second four-way valve is connected to the first end of the second pipeline, and the second end of the second pipeline forms the second external port of the outdoor unit unit. The first transmission pipeline includes one input end connected to the output end of the indoor unit unit and n first connection ends connected in one-to-one correspondence with the n first external ports of the n outdoor unit units. The second transmission pipeline includes one output end connected to the input end of the indoor unit unit and n second connection ends connected in one-to-one correspondence with the n second external ports of the n outdoor unit units. The air-conditioning heat pump system is characterized by this.

14. An air-conditioning heat pump system according to claim 13, When m first outdoor unit units out of the n outdoor unit units are in the heating mode and k second outdoor unit units out of the n outdoor unit units are in the defrosting mode, the controller controls the D end and the E end of the first four-way valve in the first outdoor unit unit to be electrically connected, the S end and the C end of the first four-way valve in the first outdoor unit unit to be electrically connected, the D end and the E end of the second four-way valve in the first outdoor unit unit to be electrically connected, the S end and the C end of the second four-way valve in the first outdoor unit unit to be electrically connected, the D end and the C end of the first four-way valve in the second outdoor unit unit to be electrically connected, the S end and the E end of the first four-way valve in the first outdoor unit unit to be electrically connected, the D end and the C end of the second four-way valve in the second outdoor unit unit to be electrically connected, and the S end and the E end of the second four-way valve in the second outdoor unit unit to be electrically connected. Here, m and k are each an integer greater than 0, and the sum of m and k is n. When m first outdoor unit units out of the n outdoor unit units are in the defrosting mode and k second outdoor unit units out of the n outdoor unit units are in the heating mode, the controller controls the D end and the C end of the first four-way valve in the first outdoor unit unit to be electrically connected, the S end and the E end of the first four-way valve in the first outdoor unit unit to be electrically connected, the D end and the C end of the second four-way valve in the first outdoor unit unit to be electrically connected, the S end and the E end of the second four-way valve in the first outdoor unit unit to be electrically connected, the D end and the E end of the first four-way valve in the second outdoor unit unit to be electrically connected, the S end and the C end of the first four-way valve in the first outdoor unit unit to be electrically connected, the D end and the E end of the second four-way valve in the second outdoor unit unit to be electrically connected, and the S end and the C end of the second four-way valve in the second outdoor unit unit to be electrically connected. The air-conditioning heat pump system is characterized by the above control.

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