Heat pump system and control method for a heat pump system

Abstract

The application relates to the technical field of heat pump systems, and discloses a heat pump system, which comprises a main circulation loop, a variable-volume compressor, a condenser, a first throttling valve, a flash evaporator, a second throttling valve and an evaporator which are sequentially connected to form a loop, the variable-volume compressor comprises an upper cylinder and a lower cylinder, and is internally provided with a variable-volume port and a supplementary air inlet; a variable-volume pipeline is in communication with the variable-volume port at one end and is divided into a first branch and a second branch at the other end, the first branch is in communication with a suction pipeline, and the second branch is in communication with a discharge pipeline; a supplementary air pipeline is in communication with the supplementary air inlet at one end and is in communication with the flash evaporator at the other end; a bypass pipeline is in communication with a pipeline between the condenser and the first throttling valve at one end and is in communication with a pipeline between the flash evaporator and the second throttling valve at the other end. The application can realize efficient energy-saving operation of the heat pump system under various working conditions, is beneficial to simultaneously meeting the wide-range capacity change of the heat pump system and the efficient operation of the heat pump system under all working conditions, and further discloses a control method for the heat pump system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of heat pump systems, for example to a heat pump system and a control method for the heat pump system. BACKGROUND

[0002] At present, with the improvement of people's living quality, the heat pump system is no longer used only for realizing single heating, hot water or drying functions. Higher demand for the heat pump system is to realize air conditioning refrigeration while heating by the heat pump, and to meet the demand for hot water when necessary, so as to realize the purpose of one machine with multiple functions. Corresponding heat pump two and three combined supply air conditioners have also been widely used. However, to simultaneously meet the requirements of high efficiency and energy saving operation of heat pump heating, air conditioning refrigeration in all working conditions, the requirements for the heat pump system itself are relatively strict. In order to solve the problem of insufficient low-temperature heating capacity of the heat pump, the heat pump compressor adopts single-stage gas supplement and enthalpy increase technology to improve the low-temperature heating capacity output of the compressor.

[0003] In the process of implementing the embodiments of the present disclosure, it is found that at least the following problems exist in the related art:

[0004] The heat pump two and three combined supply air conditioning system has a wide range of operating conditions, including low-temperature heating, refrigeration, low load or high load, etc. When the heat pump system in the related art operates in the low-pressure difference and small pressure ratio heating or refrigeration condition with increased enthalpy, the intermediate pressure of the gas supplement of the compressor is relatively difficult to control. If the intermediate pressure of the gas supplement is controlled too high, liquid will be carried by the gas supplement. If the intermediate pressure of the gas supplement is too low, the gas will not be supplemented, and the gas supplement and enthalpy increase will be worse. At this time, the control of the two-stage throttling gas supplement and enthalpy increase system is complex, and it is difficult to coordinate the control of the two electronic expansion valves, which is likely to cause the energy efficiency of the heat pump air conditioning system to be poor. When the heat pump system operates in the low load heating or refrigeration condition, the related art needs to reduce the speed of the compressor in order to reduce the capacity of the system. At this time, the electric efficiency and volumetric efficiency of the compressor operating at low speed will be reduced, and the energy efficiency of the entire heat pump system will also be reduced. Therefore, the heat pump system in the related art cannot meet the high energy efficiency requirements of low-temperature heating, refrigeration and low load operation, and it is difficult to simultaneously meet the capacity change and high energy efficiency requirements of the heat pump system in a wide range of all working conditions.

[0005] It should be noted that the information disclosed in the above BACKGROUND section is only used to strengthen the understanding of the background of the present application, and therefore can include information that does not constitute prior art known to those of ordinary skill in the art. SUMMARY

[0006] In order to have a basic understanding of some aspects of the disclosed embodiments, the following is a simple summary. The summary is not a general review, nor does it determine the key / important components or delineate the protection scope of these embodiments, but serves as a prelude to the detailed description below.

[0007] The heat pump system and the control method thereof can realize efficient and energy-saving operation under various working conditions, and can meet the wide range of capacity changes and efficient operation of the heat pump system.

[0008] In some embodiments, the heat pump system comprises: a main circulation loop, comprising a variable displacement compressor, a condenser, a first throttling valve, a flash tank, a second throttling valve and an evaporator connected in sequence through refrigerant pipelines to form a loop, the variable displacement compressor comprising an upper cylinder and a lower cylinder, and the variable displacement compressor being provided with a variable displacement port and a charge port; a variable displacement pipeline, one end of which is in communication with the variable displacement port of the variable displacement compressor, and the other end of which is divided into a first branch and a second branch, the first branch being in communication with a suction pipeline of the variable displacement compressor, and the first branch being provided with a first control valve, the second branch being in communication with a discharge pipeline of the variable displacement compressor, and the second branch being provided with a second control valve; a charge pipeline, one end of which is in communication with the charge port of the variable displacement compressor, and the other end of which is in communication with the flash tank, and the charge pipeline being provided with a third control valve; and a bypass pipeline, one end of which is in communication with a pipeline between the condenser and the first throttling valve, and the other end of which is in communication with a pipeline between the flash tank and the second throttling valve, and the bypass pipeline being provided with a fourth control valve.

[0009] In some embodiments, the charge port is arranged on the lower cylinder, and the variable displacement compressor further comprises: a one-way valve assembly, which is arranged on the lower cylinder corresponding to the charge port and is used to limit the one-way flow of the refrigerant from the charge pipeline to the lower cylinder.

[0010] In some embodiments, the one-way valve assembly comprises a one-way valve vane and a one-way valve baffle, the one-way valve vane is arranged at the charge port, and the one-way valve baffle comprises a connecting portion and a limiting portion, the connecting portion is arranged above the one-way valve vane and is fixedly connected with the one-way valve vane, and the limiting portion is arranged above the one-way valve vane opposite to the charge port, and the lower end surface of the limiting portion has a gap with the one-way valve vane for limiting the opening of the one-way valve vane.

[0011] In some embodiments, the lower cylinder is provided with a one-way valve seat, and a partition plate is arranged between the upper cylinder and the lower cylinder, the one-way valve seat and the partition plate constitute a containing cavity, and the one-way valve assembly is arranged in the containing cavity, and the distance between the upper end surface of the one-way valve baffle and the upper end surface of the lower cylinder is h, h≤0.1mm.

[0012] In some embodiments, when the one-way valve assembly is arranged in the containing cavity, the remaining volume in the containing cavity is V0, and 0.02mL≤V0≤1mL.

[0013] In some embodiments, the lower cylinder is provided with a sliding vane groove on the side facing the variable volume port, and the variable volume compressor further comprises: a variable volume sliding vane arranged in the sliding vane groove, the variable volume sliding vane being provided with a groove; a pin movably arranged below the variable volume sliding vane, the pin being provided with a protrusion at one end facing the variable volume sliding vane, the protrusion being matched with the groove of the variable volume sliding vane; and an elastic member connected with the pin, so that the pin can move between a free position and a compressed position, wherein when the pin moves to the free position, the protrusion of the pin is clamped with the groove of the variable volume sliding vane to limit the displacement of the variable volume sliding vane.

[0014] In some embodiments, the displacement of the upper cylinder is V1, and the displacement of the lower cylinder is V2, and 0.5≤V1 / V2≤0.8.

[0015] In some embodiments, the heat pump system further comprises: a third branch, one end of which is in communication with the air supplement pipeline, and the other end of which is in communication with the variable volume pipeline, and the third branch is provided with a fifth control valve.

[0016] In some embodiments, the variable volume pipeline is provided with a variable volume tank; and / or, the air supplement pipeline is provided with an air supplement tank; and / or, the suction pipeline is provided with a distributor.

[0017] In some embodiments, the method is applied to the heat pump system, and the method comprises: acquiring the operating frequency, the discharge pressure and the suction pressure of the variable volume compressor; determining the working mode of the heat pump system according to the operating frequency, the discharge pressure and the suction pressure of the variable volume compressor; and configuring the opening and closing states of the control valves according to the working mode of the heat pump system.

[0018] The heat pump system and the control method for the heat pump system provided by the embodiments of the present disclosure can achieve the following technical effects:

[0019] In the embodiments of the present disclosure, a double-cylinder variable volume compressor is adopted, which has both variable volume function and air supplement function. The heat pump system is provided with a variable volume pipeline, which is divided into a first branch in communication with the suction pipeline and a second branch in communication with the discharge pipeline. By controlling the conduction or disconnection of the first branch and the second branch, the variable volume can be adjusted to control the single-cylinder or double-cylinder operation of the variable volume compressor. At the same time, by controlling the conduction or disconnection of the air supplement pipeline of the heat pump system, the opening or closing of the air supplement and enthalpy increase function of the variable volume compressor can be controlled. The heat pump system is further provided with a bypass pipeline which is arranged in parallel with the first throttling valve and the flash tank. By controlling the conduction or disconnection of the bypass pipeline, the control of the throttling frequency can be further realized. Therefore, the embodiments of the present disclosure can construct multiple working modes to adapt to the capacity demand of the heat pump system under different working conditions, so that the heat pump system can realize efficient and energy-saving operation under various working conditions, which is conducive to meeting the wide range of capacity changes and efficient operation of the heat pump system under all working conditions.

[0020] The foregoing general description and the following description are only exemplary and explanatory, and are not intended to limit the present application. Attached Figure Description

[0021] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations and drawings do not constitute a limitation on the embodiments. Elements having the same reference numerals in the drawings are shown as similar elements. The drawings are not to be scaled. And wherein:

[0022] Figure 1 This is a schematic diagram of the structure of a heat pump system provided in an embodiment of this disclosure;

[0023] Figure 2 This is a schematic diagram of the structure of a variable capacity compressor provided in an embodiment of this disclosure;

[0024] Figure 3 This is a schematic diagram of the structure of a lower cylinder provided in an embodiment of this disclosure;

[0025] Figure 4 This is provided by the embodiments of this disclosure. Figure 3 A schematic diagram of the explosion of the lower cylinder;

[0026] Figure 5 This is a schematic diagram of the structure of a one-way valve baffle provided in an embodiment of this disclosure;

[0027] Figure 6 This is provided by the embodiments of this disclosure. Figure 2 An enlarged schematic diagram of part A;

[0028] Figure 7 This is a schematic diagram of another heat pump system provided in an embodiment of this disclosure;

[0029] Figure 8 This is a schematic diagram of a control method for a heat pump system provided in an embodiment of this disclosure;

[0030] Figure 9 This is a schematic diagram of another control method for a heat pump system provided in an embodiment of this disclosure;

[0031] Figure 10 This is a schematic diagram of another control method for a heat pump system provided in an embodiment of this disclosure;

[0032] Figure 11 This is a schematic diagram of a control device for a heat pump system provided in an embodiment of this disclosure;

[0033] Figure 12 This is a schematic diagram of an air conditioner provided in an embodiment of this disclosure.

[0034] Figure label:

[0035] 10: main circulation loop; 11: variable displacement compressor; 111: upper cylinder; 112: lower cylinder; 113: variable displacement port; 114: charge port; 115: check valve assembly; 1151: check valve flap; 1152: check valve baffle; 11521: connecting portion; 11522: limiting portion; 1153: check valve seat; 1154: check valve screw; 116: sliding vane groove; 117: variable displacement sliding vane; 1171: groove; 118: pin; 1181: protrusion; 119: elastic member; 1110: partition; 1111: lower bearing; 1112: lower cover plate; 1113: upper bearing; 1114: lower roller; 1115: crankshaft; 1116: motor rotor; 1117: motor stator; 1118: exhaust port; 12: condenser; 13: first throttle valve; 14: flash evaporator; 15: second throttle valve; 16: evaporator; 17: exhaust line; 18: suction line; 19: distributor; 20: variable displacement line; 21: first branch; 22: second branch; 23: variable displacement tank; 30: charge line; 31: charge tank; 40: bypass line; 50: third branch; 61: first control valve; 62: second control valve; 63: third control valve; 64: fourth control valve; 65: fifth control valve; 71: first pressure sensor; 72: second pressure sensor; 80: control device for heat pump system; 81: processor; 82: memory; 83: communication interface; 84: bus; 90: air conditioner body. DETAILED DESCRIPTION

[0036] In order to enable persons skilled in the art to more fully understand the features and technical contents of the embodiments of the present disclosure, the implementation of the embodiments of the present disclosure is described in detail below with reference to the accompanying drawings, which are used only for reference and do not limit the embodiments of the present disclosure. In the following technical description, in order to facilitate explanation, a plurality of details are provided to provide a full understanding of the disclosed embodiments. However, one or more embodiments can still be implemented without these details. In other cases, well-known structures and devices can be simplified to facilitate the drawings.

[0037] The terms "first", "second", and the like in the specification and claims of the embodiments of the present disclosure and the above-described drawings are used to distinguish similar objects, and do not necessarily have to describe a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present disclosure described herein can be implemented. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion.

[0038] Unless otherwise specified, the term "a plurality of" means two or more.

[0039] In the embodiments of the present disclosure, the character " / " represents an "or" relationship between the objects before and after it. For example, A / B means A or B.

[0040] The term “and / or” is a descriptive relationship between objects, which means that there can be three relationships. For example, A and / or B means that there are three relationships of A or B, or A and B.

[0041] The term “corresponds” can refer to a relationship or a binding relationship. A corresponds to B means that there is a relationship or a binding relationship between A and B.

[0042] At present, with the improvement of people's quality of life, the heat pump system is no longer used only for single heating, hot water or drying function. The higher demand for heat pump system is to realize air conditioning refrigeration while heat pump heating, and to meet the demand for hot water when necessary, so as to realize the purpose of one machine with multiple functions. Corresponding heat pump two and three supply air conditioners have also been widely used. However, to meet the requirements of heat pump heating, air conditioning refrigeration and high energy efficiency operation in all working conditions, the requirements for the heat pump system itself are relatively strict. To solve the problem of insufficient low-temperature heating capacity of the heat pump, the heat pump compressor adopts single-stage supplementary gas enthalpy increasing technology to improve the low-temperature heating capacity output of the compressor.

[0043] However, the operating condition range of the heat pump two and three supply air conditioning system is relatively wide, and there are many working conditions such as low-temperature heating, refrigeration, low load or high load. When the heat pump system in the related technology operates in the low-pressure difference and small pressure ratio heating or refrigeration condition with increased enthalpy, the supplementary gas intermediate pressure of the compressor is relatively difficult to control. If the supplementary gas intermediate pressure control is too high, it will cause liquid entrainment in the supplementary gas. If the supplementary gas intermediate pressure control is too low, it will not be able to supplement the gas, and the supplementary gas enthalpy increasing will be worse. At this time, the control of the two-stage throttling supplementary gas enthalpy increasing system is complex, and it is difficult to coordinate the control of the two electronic expansion valves, which will easily cause the energy efficiency of the heat pump air conditioning system to be poor. When the heat pump system operates in the low load heating or refrigeration condition, in order to reduce the capacity of the system, the related technology needs to reduce the speed of the compressor. At this time, the electric efficiency and volumetric efficiency of the compressor will be reduced when it operates at low speed, and the energy efficiency of the entire heat pump system will also decrease. Therefore, the heat pump system in the related technology cannot meet the high energy efficiency demand of low-temperature heating, refrigeration and low load operation, and it is difficult to meet the demand of capacity change and high energy efficiency of the heat pump system in a wide range of all working conditions.

[0044] In combination with Figure 1As shown, the embodiment of the present disclosure provides a heat pump system, comprising: a main circulation loop 10, a variable displacement pipeline 20, a gas supplement pipeline 30 and a bypass pipeline 40. The main circulation loop 10 comprises a variable displacement compressor 11, a condenser 12, a first throttle valve 13, a flash evaporator 14, a second throttle valve 15 and an evaporator 16 connected in sequence through a refrigerant pipeline to form a loop. The variable displacement compressor 11 comprises an upper cylinder 111 and a lower cylinder 112, and the variable displacement compressor 11 is provided with a variable displacement port 113 and a gas supplement port 114. The variable displacement pipeline 20 is communicated with the variable displacement port 113 of the variable displacement compressor 11 at one end, and is branched into a first branch 21 and a second branch 22 at the other end, the first branch 21 is communicated with a suction pipeline 18 of the variable displacement compressor 11, the first branch 21 is provided with a first control valve 61, the second branch 22 is communicated with a discharge pipeline 17 of the variable displacement compressor 11, and the second branch 22 is provided with a second control valve 62. The gas supplement pipeline 30 is communicated with the gas supplement port 114 of the variable displacement compressor 11 at one end, and is communicated with the flash evaporator 14 at the other end, and the gas supplement pipeline 30 is provided with a third control valve 63. The bypass pipeline 40 is communicated with a pipeline between the condenser 12 and the first throttle valve 13 at one end, and is communicated with a pipeline between the flash evaporator 14 and the second throttle valve 15 at the other end, and the bypass pipeline 40 is provided with a fourth control valve 64.

[0045] By adopting the heat pump system provided by the embodiment of the present disclosure, the double-cylinder variable displacement compressor 11 is adopted, which has both variable displacement function and gas supplement function. The heat pump system is provided with the variable displacement pipeline 20, which is branched into the first branch 21 communicated with the suction pipeline 18 and the second branch 22 communicated with the discharge pipeline 17, by controlling the conduction or disconnection of the first branch 21 and the second branch 22, the variable displacement capacity can be adjusted to control the single-cylinder or double-cylinder operation of the variable displacement compressor 11. At the same time, by controlling the conduction or disconnection of the gas supplement pipeline 30 of the heat pump system, the opening or closing of the gas supplement enthalpy increasing function of the variable displacement compressor 11 can be controlled. The heat pump system is also provided with the bypass pipeline 40, which is arranged in parallel with the first throttle valve 13 and the flash evaporator 14, by controlling the conduction or disconnection of the bypass pipeline 40, the control of the throttling frequency can be further realized. Therefore, the embodiment of the present disclosure can construct multiple working modes to adapt to the capacity demand of the heat pump system under different working condition conditions, so that the heat pump system can realize efficient and energy-saving operation under various working condition conditions, which is beneficial to simultaneously meet the wide range of capacity changes and efficient operation of the heat pump system under all working conditions.

[0046] Optionally, in combination with Figure 2As shown, the variable displacement compressor 11 comprises a housing, a motor and a body. The housing is internally configured with an accommodation space. The motor is arranged in the accommodation space and comprises a motor rotor 1116 and a motor stator 1117. The body is arranged in the accommodation space and comprises a crankshaft 1115, and an upper bearing 1113, an upper roller (not shown in the figure), an upper cylinder 111, a partition plate 1110, a lower roller 1114, a lower cylinder 112, a lower bearing 1111 and a lower cover plate 1112 which are sequentially penetrated by the crankshaft 1115 from top to bottom. The motor stator 1117 is fixedly arranged in the accommodation space, and the motor rotor 1116 is connected with the crankshaft 1115. The upper roller cooperates with the upper cylinder 111, and the lower roller 1114 cooperates with the lower cylinder 112. In this way, the rotation of the motor rotor 1116 can drive the rotation of the crankshaft 1115, and further drive the rotation of the upper roller in the upper cylinder 111 and the lower roller 1114 in the lower cylinder 112. Through the eccentric rotation of the upper roller and the lower roller 1114, the compression process of the refrigerant by the upper cylinder 111 and the lower cylinder 112 is finally realized.

[0047] Optionally, the variable displacement compressor 11 is further provided with an exhaust port 1118 and a suction port (not shown in the figure). The exhaust port 1118 is in communication with the condenser 12 to form an exhaust pipeline 17. The suction port is in communication with the evaporator 16 to form a suction pipeline 18. The suction port comprises an upper suction port and a lower suction port, and the upper suction port is arranged on the upper cylinder and the lower suction port is arranged on the lower cylinder. In this way, the refrigerant circulation can be completed through the exhaust pipeline 17 and the suction pipeline 18 in the main circulation loop 10.

[0048] Optionally, in combination with Figures 3-6 As shown, the supplementary air port 114 is arranged on the lower cylinder 112, and the variable displacement compressor further comprises a one-way valve assembly 115. The one-way valve assembly 115 is arranged on the lower cylinder 112 corresponding to the supplementary air port 114, and is used to limit the one-way flow of the refrigerant from the supplementary air pipeline 30 to the inside of the lower cylinder 112. In this way, the lower cylinder 112 can realize the independent supplementary air injection function. And by arranging the one-way valve assembly 115 at the outlet of the supplementary air port 114, the present embodiment can prevent the backflow problem of the variable displacement compressor 11, and is beneficial to improving the reliability of the supplementary air of the variable displacement compressor 11.

[0049] Optionally, the one-way valve assembly 115 comprises a one-way valve flap 1151 and a one-way valve baffle 1152. The one-way valve flap 1151 is arranged above the air supplement port 114. The one-way valve baffle 1152 comprises a connecting portion 11521 and a limiting portion 11522. The connecting portion 11521 is arranged above the one-way valve flap 1151 and is fixedly connected with the one-way valve flap 1151. The limiting portion 11522 is arranged above the one-way valve flap 1151 opposite to the air supplement port 114. The lower end surface of the limiting portion 11522 has a gap with the one-way valve flap 1151 for limiting the opening of the one-way valve flap 1151. In this way, it can be ensured that the one-way valve flap 1151 can be in sufficient contact and limiting with the one-way valve baffle 1152 when the one-way valve flap 1151 is opened, and a certain opening gap is formed to ensure that the refrigerant can flow into the lower cylinder 112 through the air supplement pipeline 30 in one direction, thereby ensuring the reliability of the one-way valve assembly 115 in air supplement.

[0050] Optionally, the upper end surface of the one-way valve baffle 1152 is a plane, the lower end surface of the connecting portion 11521 is a plane, and the lower end surface of the limiting portion 11522 is an arc surface. In this way, considering that the large clearance volume of the variable displacement compressor 11 directly affects the energy efficiency of the variable displacement compressor 11. In the embodiment of the present disclosure, the upper end surface of the one-way valve baffle 1152 is made into a plane, which can ensure that the cooperation gap between the upper end surface of the one-way valve baffle 1152 and the partition plate 1110 after assembly is minimized to reduce the clearance volume after cooperation. That is, the clearance volume of the variable displacement compressor 11 is reduced, thereby being conducive to improving the energy efficiency of the variable displacement compressor 11. And the lower end surface of the one-way valve baffle 1152 located at the limiting portion 11522 is made into an arc surface, which can ensure that the one-way valve flap 1151 can be in sufficient contact and limiting with the one-way valve baffle 1152 when the one-way valve flap 1151 is opened, and a certain opening gap is formed to ensure that the refrigerant can flow into the lower cylinder 112 through the air supplement pipeline 30 in one direction, thereby ensuring the reliability of the one-way valve assembly 115 in air supplement.

[0051] Optionally, the one-way valve assembly 115 is arranged in the accommodating cavity between the one-way valve seat 1153 and the partition plate 1110. The distance between the upper end surface of the one-way valve baffle 1152 and the upper end surface of the lower cylinder 112 is h, and h≤0.1mm. In this way, considering that the large clearance volume of the variable displacement compressor 11 directly affects the energy efficiency of the variable displacement compressor 11. In the embodiment of the present disclosure, the one-way valve assembly 115 is arranged in the accommodating cavity between the one-way valve seat 1153 and the partition plate 1110, and the cooperation gap between the upper end surface of the one-way valve baffle 1152 and the partition plate 1110 after assembly is controlled to be not greater than 0.1mm, so as to reduce the clearance volume as much as possible on the premise of ensuring the air supplement reliability of the one-way valve assembly 115, thereby being conducive to improving the energy efficiency of the variable displacement compressor 11.

[0052] Preferably, the distance h between the upper end surface of the check valve baffle 1152 and the upper end surface of the lower cylinder 112 is 0.07 mm, which can reduce the residual volume as much as possible under the premise of ensuring the reliability of the check valve assembly 115, thereby improving the energy efficiency of the variable displacement compressor 11. h can also be adjusted according to the specific design requirements of the variable displacement compressor 11, and can also be set to 0.02 mm or 0.09 mm or other reasonable values.

[0053] Optionally, when the check valve assembly 115 is arranged in the accommodation cavity, the remaining volume in the accommodation cavity is V0, 0.02 mL≤V0≤1 mL. In this way, when the check valve assembly 115 is arranged in the accommodation cavity between the check valve seat 1153 and the partition plate 1110, the disclosure embodiment controls the residual volume formed by the check valve assembly 115, the check valve seat 1153 and the partition plate 1110 after cooperation to be between 0.02 mL and 1 mL. On the one hand, it can avoid that when V0 is greater than 1 mL, the residual volume of the variable displacement compressor 11 is too large, which directly affects the energy efficiency of the variable displacement compressor 11. On the other hand, it can avoid that when V0 is less than 0.02 mL, the remaining volume in the accommodation cavity is too small, which causes the refrigerant flow to be blocked, thereby affecting the reliability of the gas supplement pipeline 30 to supplement gas into the lower cylinder 112.

[0054] Preferably, when the check valve assembly 115 is arranged in the accommodation cavity, the remaining volume V0 in the accommodation cavity is 0.7 mL, which can better balance the reliability of the gas supplement through the check valve assembly 115 and the energy efficiency of the variable displacement compressor 11. V0 can also be adjusted according to the specific design requirements of the variable displacement compressor 11, and can also be set to 0.2 mL or 0.9 mL or other reasonable values.

[0055] Optionally, the check valve assembly 115 further comprises a check valve screw 1154. The check valve screw 1154 sequentially fixes the check valve disc 1151 and the connecting part 11521 of the check valve baffle 1152 on the check valve seat 1153. In this way, it can ensure that the refrigerant can flow more stably into the lower cylinder 112, so as to further improve the reliability of the gas supplement through the check valve assembly 115.

[0056] Optionally, the lower cylinder 112 is provided with a sliding vane groove 116 on the side close to the variable displacement port 113, and the variable displacement compressor 11 further comprises a variable displacement sliding vane 117, a pin 118 and an elastic member 119. The variable displacement sliding vane 117 is arranged in the sliding vane groove 116, and the variable displacement sliding vane 117 is provided with a groove 1171. The pin 118 is movably arranged below the variable displacement sliding vane 117, and the pin 118 is provided with a protrusion 1181 on the end close to the variable displacement sliding vane 117, and the protrusion 1181 is matched with the groove 1171 of the variable displacement sliding vane 117. The elastic member 119 is connected with the pin 118, so that the pin 118 can move between a free position and a compression position. When the pin 118 moves to the free position, the protrusion 1181 of the pin 118 is clamped with the groove 1171 of the variable displacement sliding vane 117, so as to limit the displacement of the variable displacement sliding vane 117. In this way, the variable displacement port 113 is communicated with the cavity at the tail of the variable displacement sliding vane 117. Since the variable displacement pipeline 20 is divided into a first branch 21 communicated with the suction pipeline 18 and a second branch 22 communicated with the exhaust pipeline 17, by controlling the conduction or disconnection of the first branch 21 and the second branch 22, the suction low pressure or the exhaust high pressure can flow to the cavity at the tail of the variable displacement sliding vane 117, so as to adjust the variable displacement to realize single-cylinder or double-cylinder operation of the variable displacement compressor 11.

[0057] When the first branch 21 is conducted and the second branch 22 is disconnected, the cavity at the tail of the variable displacement sliding vane 117 is communicated with the suction pipeline 18 of the variable displacement compressor 11, at this time, the tail and the head of the variable displacement sliding vane 117 are both under the suction low pressure, and there is no pressure difference between the front and the back, and the upward elastic force of the elastic member 119 to the pin 118 is greater than the downward pressure of the suction low pressure, so that the pin 118 moves upward under the action of the elastic member 119. When the pin 118 moves to the free position, the protrusion 1181 on the upper end of the pin 118 is clamped with the groove 1171 on the lower end of the variable displacement sliding vane 117, so as to limit the displacement of the variable displacement sliding vane 117. At this time, the variable displacement sliding vane 117 is separated from the lower roller 1114, the lower cylinder 112 stops working, and the variable displacement compressor 11 operates in single-cylinder mode.

[0058] When the second branch 22 is conducted and the first branch 21 is disconnected, the cavity at the tail of the variable displacement sliding vane 117 is communicated with the exhaust pipeline 17 of the variable displacement compressor 11, at this time, the cavity at the tail of the variable displacement sliding vane 117 is under the exhaust high pressure, and the head is under the suction low pressure, so that a high pressure difference is formed between the front and the back, and the variable displacement sliding vane 117 has a tendency to slide towards the lower roller 1114. At this time, the downward pressure of the exhaust high pressure is greater than the upward elastic force of the elastic member 119 to the pin 118, so that the pin 118 moves downward under the action of the exhaust high pressure and overcomes the elastic force of the elastic member 119. When the pin 118 moves to the compression position, the protrusion 1181 on the upper end of the pin 118 is separated from the groove 1171 on the lower end of the variable displacement sliding vane 117, at this time, the variable displacement sliding vane 117 slides towards the lower roller 1114 until abutting against the lower roller 1114, the lower cylinder 112 starts to work, and the variable displacement compressor 11 operates in double-cylinder mode.

[0059] Optionally, the lower bearing 1111 is configured with a pin hole, and the pin 118 is arranged in the pin hole. The elastic member 119 is a pin spring, and the elastic member 119 is fixedly connected with the lower cover plate 1112. In this way, under the action of the unbalanced force at the upper and lower ends, the pin 118 can move up and down between the free position and the pressing position in the pin hole, so as to realize the contact or disengagement of the pin 118 with the variable displacement slide 117, and then complete the switching of the single-cylinder or double-cylinder operation of the variable displacement compressor 11.

[0060] Optionally, the displacement of the upper cylinder is V1, the displacement of the lower cylinder is V2, and 0.5≤V1 / V2≤0.8. In this way, when the variable displacement compressor 11 outputs a small capacity, the disclosed embodiment can make the rotation speed of the single-cylinder operation be at a suitable frequency, so as to ensure that the volumetric efficiency and the electric efficiency of the variable displacement compressor 11 are at a better level. On the one hand, it can avoid that when V1 / V2 is less than 0.5, the displacement ratio of the upper and lower cylinders is too small, which leads to that the operation frequency of the variable displacement compressor 11 is too high, and the motor efficiency is reduced. On the other hand, it can avoid that when V1 / V2 is greater than 0.8, the displacement ratio of the upper and lower cylinders is too large, which leads to that the capacity is excessive, the frequency is too low, and the volumetric efficiency of the compressor and the electric efficiency of the motor are both low.

[0061] Preferably, the ratio V1 / V2 of the displacement of the upper cylinder to the displacement of the lower cylinder is 0.6, which can better balance the volumetric efficiency and the electric efficiency of the variable displacement compressor 11. V1 / V2 can also be adjusted according to the specific design requirements of the variable displacement compressor 11, and can also be set to 0.55 or 0.7 or other arbitrary reasonable values.

[0062] Optionally, in combination with Figure 7 As shown in the figure, the heat pump system further comprises a third branch 50. One end of the third branch 50 is in communication with the air supplement pipeline 30, the other end is in communication with the variable displacement pipeline 20, and the third branch 50 is provided with a fifth control valve 65.

[0063] The tail part of the variable displacement slide 117 in the lower cylinder 112 is a sealed cavity, and the clearance between the variable displacement slide 117 and the slide groove 116 is an oil-gas mixture. Considering that the cavity is communicated with high-pressure gas when the lower cylinder 112 is working, at this time, the suction side of the lower cylinder 112 is low-pressure gas, that is, the high-pressure gas at the tail part of the variable displacement slide 117 and the low-pressure gas at the head part of the variable displacement slide 117 form a high pressure difference. When the lower cylinder 112 operates at a high pressure difference, the high pressure at the tail part of the variable displacement slide 117 will leak to the suction side of the cylinder through the clearance of the slide groove 116, which will reduce the volumetric efficiency of the lower cylinder 112 and increase the power consumption. In this case, the disclosed embodiment can control the third branch 50 to be conducted or disconnected, so as to control the medium-pressure air supplement to the tail part of the variable displacement slide 117, thereby relatively reducing the pressure difference between the tail part and the head part of the variable displacement slide 117. Therefore, the disclosed embodiment can reduce the leakage of the slide groove 116, which is conducive to improving the energy efficiency of the variable displacement compressor 11.

[0064] Optionally, the variable displacement pipeline 20 is provided with a variable displacement tank 23. In this way, the variable displacement tank 23 can reduce the pressure pulsation in the variable displacement pipeline 20, and can separate the refrigerant in the variable displacement pipeline 20 into gas and liquid, thereby avoiding the liquid refrigerant directly entering the variable displacement compressor 11 to cause the liquid knock phenomenon, and being beneficial to improving the service life of the variable displacement compressor 11.

[0065] Optionally, the supplementary pipeline 30 is provided with a supplementary tank 31. In this way, the supplementary tank 31 can reduce the pressure pulsation in the supplementary pipeline 30, and can separate the refrigerant in the supplementary pipeline 30 into gas and liquid, thereby avoiding the liquid refrigerant directly entering the variable displacement compressor 11 to cause the liquid knock phenomenon, and being beneficial to improving the service life of the variable displacement compressor 11.

[0066] Optionally, the suction pipeline 18 is provided with a liquid separator 19. In this way, the liquid separator 19 can reduce the pressure pulsation in the suction pipeline 18, and can separate the refrigerant in the suction pipeline 18 into gas and liquid, thereby avoiding the liquid refrigerant directly entering the variable displacement compressor 11 to cause the liquid knock phenomenon, and being beneficial to improving the service life of the variable displacement compressor 11.

[0067] Optionally, the exhaust pipeline 17 is provided with a first pressure sensor 71 configured to obtain the exhaust pressure of the variable displacement compressor 11. The suction pipeline 18 is provided with a second pressure sensor 72 configured to obtain the suction pressure of the variable displacement compressor 11. In this way, the exhaust pressure and the suction pressure of the variable displacement compressor 11 can be monitored, so that the actual operation condition of the heat pump system can be analyzed, and the most suitable working mode can be matched to adapt to the capacity demand of the heat pump system under different working condition conditions.

[0068] Optionally, the first control valve 61, the second control valve 62, the third control valve 63, the fourth control valve 64, and the fifth control valve 65 are solenoid valves. In this way, by controlling the opening and closing states of the solenoid valves, the corresponding pipeline can be controlled to be turned on or turned off, so as to complete the switching of the working mode of the heat pump system.

[0069] Based on the above heat pump system, combined with Figure 8 as shown, the embodiment of the present disclosure provides a control method for a heat pump system, comprising:

[0070] S801, the processor obtains the operating parameters of the heat pump system.

[0071] S802, the processor determines the working mode of the heat pump system according to the operating parameters of the heat pump system.

[0072] S803, the processor configures the opening and closing states of each control valve according to the working mode of the heat pump system.

[0073] By using the control for the heat pump system provided in the embodiments of the present disclosure, multiple working modes can be constructed through corresponding pipeline design to adapt to the capacity demand of the heat pump system under different working conditions. On this basis, by obtaining the operating parameters of the heat pump system, the embodiments of the present disclosure can analyze the actual operating conditions of the heat pump system and can match the most suitable working mode accordingly. Then by adjusting the opening and closing states of the corresponding control valves on the first branch, the second branch, the air supplement pipeline and the bypass pipeline, the corresponding pipelines can be turned on or turned off, so as to realize intelligent control of the heat pump system entering the most suitable working mode, so that the heat pump system can realize efficient and energy-saving operation under various working conditions, which is conducive to meeting the wide range of capacity changes and efficient operation of the heat pump system under all working conditions.

[0074] Optionally, the operating parameters of the heat pump system include the operating frequency, the discharge pressure and the suction pressure of the variable displacement compressor. In this way, by monitoring the above operating parameters, the embodiments of the present disclosure can analyze the actual operating conditions of the heat pump system, which is conducive to matching the most suitable working mode to adapt to the capacity demand of the heat pump system under different working conditions.

[0075] Optionally, the processor determines the working mode of the heat pump system according to the operating parameters of the heat pump system, including: in the case that the operating frequency of the variable displacement compressor is less than a preset operating frequency, and / or, the pressure difference between the discharge pressure and the suction pressure of the variable displacement compressor is less than or equal to a first pressure difference, the processor determines that the working mode of the heat pump system is a single-cylinder mode; or, in the case that the operating frequency of the variable displacement compressor is greater than or equal to the preset operating frequency, and the pressure difference between the discharge pressure and the suction pressure of the variable displacement compressor is greater than the first pressure difference, the processor determines that the working mode of the heat pump system is a double-cylinder mode.

[0076] Thus, when the operating frequency of the variable displacement compressor is less than the preset operating frequency, and / or, the pressure difference between the discharge pressure and the suction pressure of the variable displacement compressor is less than or equal to the first pressure difference, the variable displacement compressor is in a low-load small-capacity output state regardless of whether the heat pump system is in a cooling or heating operating condition. If the operating frequency of the variable displacement compressor is too low, the motor efficiency and volumetric efficiency of the variable displacement compressor will be greatly reduced, resulting in a decrease in the energy efficiency of the entire heat pump system. At this time, the pressure difference between the discharge pressure and the suction pressure of the variable displacement compressor is small, and if the two-throttle intermediate-charge method is used, the intermediate pressure is between the suction pressure and the discharge pressure, and it is relatively difficult to control the intermediate pressure of the variable displacement compressor. If the intermediate pressure of the charge is controlled too high, the charge will carry liquid, which will pose a great risk to the reliability of the compressor, and if the intermediate pressure of the charge is controlled too low, the charge will not be sufficient, and the enthalpy increase of the charge will be poor. In this operating condition, it is difficult to balance the opening of the two throttles, and the complex control of the throttles will waste a certain amount of electrical energy, resulting in a relatively low energy efficiency of the heat pump system. Therefore, to adapt to the light-load small-pressure-difference operating condition of the heat pump system, the heat pump system is operated in a single-cylinder mode, and the heat pump system is closed to charge and operated in a one-throttle mode, at this time, the discharge of the variable displacement compressor only needs to be throttled once after being condensed by the condenser to meet the evaporation requirement of the refrigerant. At the same time, since the upper and lower cylinders of the variable displacement compressor are designed with different displacements, at this time, only the upper cylinder of the compressor is operated, the operating displacement of the compressor is small, and the operating frequency of the variable displacement compressor can be as high as possible for the same cooling capacity output, so the single-cylinder mode can guarantee the high volumetric efficiency and high electrical efficiency of the variable displacement compressor in the low-load operating condition.

[0077] When the operating frequency of the variable displacement compressor is greater than or equal to the preset operating frequency, and the pressure difference between the discharge pressure and the suction pressure of the variable displacement compressor is greater than the first pressure difference, the variable displacement compressor is in a high-load large-capacity output state regardless of whether the heat pump system is in a cooling or heating operating condition. At this time, to guarantee the capacity of the variable displacement compressor to be output efficiently, the heat pump system is operated in a double-cylinder mode, and the upper and lower cylinders of the variable displacement compressor work simultaneously, so as to meet the capacity requirement of the heat pump system.

[0078] Optionally, the processor determines the operating mode of the heat pump system to be a double-cylinder mode, including: in the case that the pressure ratio of the discharge pressure and the suction pressure of the variable displacement compressor is less than or equal to a preset pressure ratio, the processor determines the operating mode of the heat pump system to be a double-cylinder normal mode; or, in the case that the pressure ratio of the discharge pressure and the suction pressure of the variable displacement compressor is greater than the preset pressure ratio, the processor determines the operating mode of the heat pump system to be a double-cylinder enthalpy-increasing mode.

[0079] In this way, when the variable displacement compressor is in a high-load large-capacity output state, the embodiment of the present disclosure causes the heat pump system to operate in a double-cylinder mode to meet the capacity demand of the heat pump system. On this basis, the embodiment of the present disclosure further compares the pressure ratio of the discharge pressure to the suction pressure of the variable displacement compressor to analyze the discharge temperature and the actual capacity output of the variable displacement compressor at this time, so as to further optimize the working mode of the heat pump system.

[0080] When the pressure ratio of the discharge pressure to the suction pressure of the variable displacement compressor is less than or equal to the preset pressure ratio, the ratio and the difference between the discharge pressure and the suction pressure of the variable displacement compressor at this time are not large, and the variable displacement compressor does not need to be supplemented with air, and the discharge temperature and the operating capacity can still be maintained at a good level. Therefore, the embodiment of the present disclosure causes the heat pump system to operate in a double-cylinder normal mode, at this time the air supplement function is closed, and the heat pump system only performs throttling operation once. The double-cylinder normal mode can make the heat pump system operate efficiently in a large-capacity and low-pressure ratio operating range, and can solve the problem that the pressure of the existing heat pump system is difficult to control twice in the low-pressure ratio throttling air supplement.

[0081] When the pressure ratio of the discharge pressure to the suction pressure of the variable displacement compressor is greater than the preset pressure ratio, the variable displacement compressor operates at a high pressure ratio, at this time the suction density of the variable displacement compressor decreases, the suction volume decreases, and the discharge temperature is too high. The excessively high discharge temperature will have an adverse effect on the reliability of the compressor motor and the compressor pump body parts, which may cause irreversible phenomena such as demagnetization of the motor magnet and wear of the pump body parts, and the compressor capacity will be significantly attenuated. At this time, intermediate air supplement is needed to increase the suction volume of the variable displacement compressor and reduce the discharge temperature of the variable displacement compressor, so as to adapt to the high-pressure ratio capacity and energy efficiency demand. Therefore, the embodiment of the present disclosure causes the heat pump system to operate in a double-cylinder enthalpy-increasing mode, at this time the heat pump system opens the air supplement function, the discharge of the variable displacement compressor is condensed by the condenser and then throttled twice to meet the intermediate air supplement and the evaporator refrigerant demand, and the lower cylinder of the variable displacement compressor works independently. At this time, the double-cylinder enthalpy-increasing mode can make the heat pump system operate efficiently in a large-capacity and high-pressure ratio operating range, and can solve the problem of insufficient operating capacity and excessively high discharge temperature of the heat pump system in a high-pressure ratio operating condition.

[0082] Optionally, the processor determines the working mode of the heat pump system to be a double-cylinder enthalpy-increasing mode, comprising: in the case that the pressure difference between the discharge pressure and the suction pressure of the variable displacement compressor is less than a second pressure difference, the processor determines the working mode of the heat pump system to be a first double-cylinder enthalpy-increasing mode; or in the case that the pressure difference between the discharge pressure and the suction pressure of the variable displacement compressor is greater than or equal to the second pressure difference, the processor determines the working mode of the heat pump system to be a second double-cylinder enthalpy-increasing mode. The second pressure difference is greater than the first pressure difference.

[0083] In this way, when the heat pump system is in the large-capacity and high-pressure ratio operating range, the heat pump system is operated in the double-cylinder enthalpy-increasing mode according to the embodiments of the present disclosure, so as to solve the problems of insufficient operating capacity and excessively high exhaust temperature of the heat pump system in the high-pressure ratio operating condition, and facilitate efficient operation of the heat pump system. On this basis, the pressure difference between the exhaust pressure and the suction pressure of the variable displacement compressor is compared again according to the embodiments of the present disclosure, so as to analyze the leakage amount of the vane groove when the lower cylinder operates at a high pressure difference, and thus the working mode of the heat pump system can be further optimized.

[0084] When the pressure difference between the exhaust pressure and the suction pressure of the variable displacement compressor is less than the second pressure difference, the pressure difference between the tail part and the head part of the variable displacement vane is relatively small, at this time, the leakage amount of the vane groove is not large, so there is no need to supply the middle pressure air to the tail part of the variable displacement vane. Therefore, the heat pump system is operated in the first double-cylinder enthalpy-increasing mode according to the embodiments of the present disclosure, at this time, the tail part of the variable displacement vane is supplied with the high-pressure exhaust air, so as to avoid the problem of impact noise caused by the separation of the variable displacement vane from the lower roller due to the excessively small pressure difference between the tail part and the head part of the variable displacement vane. At this time, the first double-cylinder enthalpy-increasing mode can make the heat pump system operate efficiently in the large-capacity and high-pressure ratio operating range on the premise that the leakage amount of the vane groove is not large, and can solve the problems of insufficient operating capacity, excessively high exhaust temperature and impact noise of the heat pump system in the high-pressure ratio operating condition.

[0085] When the pressure difference between the exhaust pressure and the suction pressure of the variable displacement compressor is greater than or equal to the second pressure difference, at this time, the pressure difference between the tail part and the head part of the variable displacement vane is large, and the leakage amount of the vane groove is greatly increased, that is, the high pressure of the tail part of the variable displacement vane will leak to the suction side of the cylinder through the vane groove gap, which will reduce the volumetric efficiency of the lower cylinder and increase the power consumption. Therefore, it is necessary to reduce the pressure difference between the tail part and the head part of the variable displacement vane to control the leakage amount of the vane groove. For this purpose, the heat pump system is operated in the second double-cylinder enthalpy-increasing mode according to the embodiments of the present disclosure, at this time, the tail part of the variable displacement vane is switched from being supplied with the high-pressure exhaust air to being supplied with the middle-pressure air, so as to reduce the pressure difference between the tail part and the head part of the variable displacement vane and greatly reduce the leakage amount of the vane groove, which is conducive to improving the energy efficiency of the variable displacement compressor. Therefore, the second double-cylinder enthalpy-increasing mode can make the heat pump system operate efficiently in the large-capacity, high-pressure ratio and high-pressure difference operating range, and can solve the problems of insufficient operating capacity, high exhaust temperature and variable displacement cylinder leakage of the heat pump system in the high-pressure ratio and high-pressure difference operating condition.

[0086] Optionally, the processor configures the opening and closing states of each control valve according to the working mode of the heat pump system, including: in the case that the working mode of the heat pump system is the single-cylinder mode, controlling the first control valve and the fourth control valve to be opened, and controlling the second control valve, the third control valve and the fifth control valve to be closed.

[0087] Thus, when the operating frequency of the variable displacement compressor is less than the preset operating frequency, and / or the pressure difference between the discharge pressure and the suction pressure of the variable displacement compressor is less than or equal to the first pressure difference, the variable displacement compressor is in a low-load small-capacity output state, the disclosed embodiments make the heat pump system operate in a single-cylinder mode, and the air supplement function is closed, so as to ensure the high volumetric efficiency and high electrical efficiency of the variable displacement compressor during low-load operation. Specifically, the disclosed embodiments open the first control valve to conduct the first branch, and the suction low pressure is introduced to the tail of the variable displacement slide, at this time, there is no obvious pressure difference between the tail and the head of the variable displacement slide. The pin is clamped with the variable displacement slide under the action of the elastic element, and the contact between the pin and the lower roller is limited, so that the lower cylinder stops working, and the variable displacement compressor operates in a single-cylinder mode. Since the upper and lower cylinders of the variable displacement compressor are designed with different displacements, at this time, the variable displacement compressor only operates with the upper cylinder, and the operating displacement of the compressor is small, so the operating frequency of the variable displacement compressor can be as high as possible with the same cooling capacity output, so as to ensure the high volumetric efficiency and high electrical efficiency of the variable displacement compressor during low-load operation. At the same time, the disclosed embodiments open the fourth control valve to conduct the bypass pipeline, so that the first throttle valve and the flash evaporator are bypassed. At this time, the heat pump system only performs one throttling, and the discharge of the variable displacement compressor can meet the evaporation requirement of the refrigerant after being condensed by the condenser and then being throttled once, and the problem that the air supplement pressure is difficult to control due to twice throttling at a low pressure difference in the existing heat pump system can be solved, which is beneficial to improving the energy efficiency of the heat pump system.

[0088] Optionally, the processor configures the opening and closing states of each control valve according to the working mode of the heat pump system, including: in the case that the working mode of the heat pump system is a double-cylinder normal mode, the second control valve and the fourth control valve are controlled to be opened, and the first control valve, the third control valve and the fifth control valve are controlled to be closed.

[0089] Thus, when the operating frequency of the variable capacity compressor is greater than or equal to the preset operating frequency, and the pressure difference between the exhaust pressure and the suction pressure of the variable capacity compressor is greater than the first pressure difference value and less than the second pressure difference value, and the pressure ratio of the exhaust pressure to the suction pressure of the variable capacity compressor is greater than the preset pressure ratio, the heat pump system is in a large-capacity and high-pressure ratio operating range, and the heat pump system according to the embodiment of the present disclosure operates in the first dual-cylinder superheat-increasing mode to enable the heat pump system to operate efficiently. Specifically, the second control valve is opened to conduct the second branch, and the exhaust high pressure is supplied to the tail of the variable capacity vane, so that the tail and the head of the variable capacity vane form a high pressure difference. The variable capacity vane slides towards the lower roller until it abuts against the lower roller, so that the lower cylinder starts to work, and the variable capacity compressor operates in the dual-cylinder mode, thereby ensuring that the variable capacity compressor has a high-efficiency output. At the same time, the third control valve is opened to conduct the air supplement pipeline, so that the first throttle valve and the flash tank are bypassed. At this time, the heat pump system only has one throttling, and the exhaust of the variable capacity compressor can meet the evaporation requirement of the refrigerant after being condensed by the condenser and being throttled once. At this time, the heat pump system can operate efficiently in the large-capacity and high-pressure ratio operating range, and can solve the problem that the air supplement pressure is difficult to control in the low-pressure ratio and twice-throttling air supplement of the existing heat pump system, which is conducive to improving the energy efficiency of the heat pump system.

[0090] Optionally, the processor configures the opening and closing states of the control valves according to the working mode of the heat pump system, including: in the case that the working mode of the heat pump system is the first dual-cylinder superheat-increasing mode, the second control valve and the third control valve are controlled to be opened, and the first control valve, the fourth control valve and the fifth control valve are controlled to be closed.

[0091] Thus, when the operating frequency of the variable capacity compressor is greater than or equal to the preset operating frequency, and the pressure difference between the exhaust pressure and the suction pressure of the variable capacity compressor is greater than the first pressure difference value and less than the second pressure difference value, and the pressure ratio of the exhaust pressure to the suction pressure of the variable capacity compressor is greater than the preset pressure ratio, the heat pump system is in a large-capacity and high-pressure ratio operating range, and the heat pump system according to the embodiment of the present disclosure operates in the first dual-cylinder superheat-increasing mode to enable the heat pump system to operate efficiently. Specifically, the second control valve is opened to conduct the second branch, and the exhaust high pressure is supplied to the tail of the variable capacity vane, so that the tail and the head of the variable capacity vane form a high pressure difference. The variable capacity vane slides towards the lower roller until it abuts against the lower roller, so that the lower cylinder starts to work, and the variable capacity compressor operates in the dual-cylinder mode, thereby ensuring that the variable capacity compressor has a high-efficiency output. At the same time, the third control valve is opened to conduct the air supplement pipeline, so that the first throttle valve and the flash tank are bypassed. At this time, the heat pump system only has one throttling, and the exhaust of the variable capacity compressor can meet the evaporation requirement of the refrigerant after being condensed by the condenser and being throttled once. At this time, the heat pump system can operate efficiently in the large-capacity and high-pressure ratio operating range, and can solve the problem that the air supplement pressure is difficult to control in the low-pressure ratio and twice-throttling air supplement of the existing heat pump system, which is conducive to improving the energy efficiency of the heat pump system.

[0092] Optionally, the processor configures the opening and closing states of the control valves according to the working mode of the heat pump system, including: in the case that the working mode of the heat pump system is the second double-cylinder enthalpy-increasing mode, the third control valve and the fifth control valve are controlled to be opened, and the first control valve, the second control valve and the fourth control valve are controlled to be closed.

[0093] In this way, when the operating frequency of the variable capacity compressor is greater than or equal to the preset operating frequency, and the pressure difference between the exhaust pressure and the suction pressure of the variable capacity compressor is greater than or equal to the second pressure difference value, and the pressure ratio of the exhaust pressure to the suction pressure of the variable capacity compressor is greater than the preset pressure ratio value, the heat pump system is in a large capacity, high pressure ratio and high pressure difference operating range, the heat pump system is operated in the second double-cylinder enthalpy-increasing mode to reduce the leakage of the vane groove, which is beneficial to improve the energy efficiency of the variable capacity compressor. Specifically, the fifth control valve is opened to conduct the third branch to supply the medium pressure air to the tail of the variable capacity vane, and a certain pressure difference is formed between the tail and the head of the variable capacity vane to ensure that the variable capacity compressor can maintain double-cylinder operation. And the gas pressure difference between the tail and the head of the variable capacity vane can be relatively reduced, the leakage of the vane groove is greatly reduced, which is beneficial to improve the energy efficiency of the variable capacity compressor. At the same time, the third control valve is opened to conduct the air supply pipeline, so that the air supply enthalpy-increasing function can be turned on. At this time, the exhaust gas of the variable capacity compressor is condensed twice through the condenser to meet the requirements of intermediate air supply and evaporator refrigerant, and the lower cylinder of the variable capacity compressor works independently. At this time, the heat pump system can operate efficiently in a large capacity, high pressure ratio and high pressure difference operating range, and can solve the problems of insufficient operating capacity, too high exhaust temperature and variable capacity cylinder leakage in the high pressure ratio and high pressure difference operating range of the heat pump system.

[0094] Optionally, the preset operating frequency can be set in combination with the actual capacity of the variable capacity compressor. Preferably, the preset operating frequency is 50 Hz. The preset operating frequency can also be adjusted according to the external environmental conditions, and can also be set to 45 Hz or 55 Hz or other arbitrary reasonable values.

[0095] Optionally, the first pressure difference value can be set in combination with the actual capacity of the variable capacity compressor. Preferably, the first pressure difference value is 0.5 MPa. The first pressure difference value can also be adjusted according to the external environmental conditions, and can also be set to 0.4 MPa or 0.6 MPa or other arbitrary reasonable values.

[0096] Optionally, the second pressure difference value can be set in combination with the actual capacity of the variable capacity compressor. Preferably, the second pressure difference value is 1.5 MPa. The second pressure difference value can also be adjusted according to the external environmental conditions, and can also be set to 1.4 MPa or 1.6 MPa or other arbitrary reasonable values.

[0097] Optionally, the preset pressure ratio can be set in combination with the actual capacity of the variable displacement compressor. Preferably, the preset pressure ratio is 3.0. The preset pressure ratio can also be adjusted according to external environmental conditions, and can also be set to 2.8 or 3.2 or any other reasonable value.

[0098] Based on the above heat pump system, in combination with Figure 9 As shown in the figure, the embodiment of the present disclosure provides another control method for a heat pump system, comprising:

[0099] S901, the processor acquires the operating frequency, discharge pressure and suction pressure of the variable displacement compressor.

[0100] S902, the processor determines the working mode of the heat pump system according to the operating frequency, discharge pressure and suction pressure of the variable displacement compressor.

[0101] S903, the processor configures the opening and closing state of each control valve according to the working mode of the heat pump system.

[0102] The control method for the heat pump system provided by the embodiment of the present disclosure can construct multiple working modes through corresponding pipeline design to adapt to the capacity demand of the heat pump system under different working conditions. On this basis, the embodiment of the present disclosure can analyze the actual operating state of the variable displacement compressor by acquiring the operating frequency, discharge pressure and suction pressure of the variable displacement compressor, and can match the most suitable working mode accordingly. Then by adjusting the opening and closing state of the corresponding control valve on the first branch, the second branch, the gas supplement pipeline and the bypass pipeline, the corresponding pipeline can be turned on or turned off, so as to realize intelligent control of the heat pump system entering the most suitable working mode, so that the heat pump system can realize efficient and energy-saving operation under various working conditions, which is conducive to meeting the wide range of capacity changes and efficient operation of the heat pump system.

[0103] In the embodiment of the present disclosure, the specific execution mode of the related steps can be referred to the foregoing, which will not be repeated here.

[0104] Based on the above heat pump system, in combination with Figure 10 As shown in the figure, the embodiment of the present disclosure provides another control method for a heat pump system, comprising:

[0105] S1001, the processor acquires the operating frequency, discharge pressure and suction pressure of the variable displacement compressor.

[0106] S1002, the processor determines the working mode of the heat pump system according to the operating frequency, discharge pressure and suction pressure of the variable displacement compressor.

[0107] S1003, the processor configures the opening and closing state of each control valve according to the working mode of the heat pump system.

[0108] S1004, the processor adjusts the opening degree of the first throttling valve and / or the second throttling valve according to the operating parameter of the heat pump system.

[0109] By using the control for the heat pump system provided in the embodiments of the present disclosure, various working modes can be constructed through corresponding pipeline design to adapt to the capacity demand of the heat pump system under different working conditions. On this basis, the embodiments of the present disclosure can analyze the actual working condition of the heat pump system by obtaining the operating parameter of the heat pump system, and can match the most suitable working mode accordingly. Then, by adjusting the opening and closing state of the corresponding control valve on the first branch, the second branch, the gas supplement pipeline and the bypass pipeline, the corresponding pipeline can be controlled to be conducted or disconnected, so as to realize intelligent control of the heat pump system entering the most suitable working mode, so that the heat pump system can realize efficient and energy-saving operation under various working conditions, which is beneficial to simultaneously meet the wide range of capacity changes and efficient operation of the heat pump system under all working conditions. In addition, the embodiments of the present disclosure further adjust the opening degree of the first throttling valve and / or the second throttling valve in combination with the operating parameter of the heat pump system to meet the intermediate gas supplement and refrigerant evaporation demand, thereby facilitating stable operation of the heat pump system.

[0110] Optionally, the operating parameter of the heat pump system further includes the discharge temperature of the variable displacement compressor. In this way, by monitoring the discharge temperature, the embodiments of the present disclosure can judge the reliability of the operation of the variable displacement compressor, so as to further grasp the actual working condition of the heat pump system, which is beneficial to timely correct the bad working condition.

[0111] Optionally, the processor adjusts the opening degree of the first throttling valve and / or the second throttling valve according to the operating parameter of the heat pump system, including: the processor determines a target throttling valve from the first throttling valve and the second throttling valve according to the working mode of the heat pump system; and the processor adjusts the opening degree of the target throttling valve according to the discharge temperature of the variable displacement compressor. In this way, the embodiments of the present disclosure can reasonably adjust the opening degree of the first throttling valve or the second throttling valve corresponding to the actual working mode of the heat pump system in combination with the discharge temperature of the variable displacement compressor, so as to better meet the intermediate gas supplement and refrigerant evaporation demand, thereby facilitating stable operation of the heat pump system.

[0112] Optionally, the processor determines the target throttle valve from the first throttle valve and the second throttle valve according to the working mode of the heat pump system, including: determining the second throttle valve as the target throttle valve when the working mode of the heat pump system is the single-cylinder mode or the double-cylinder normal mode; or determining the first throttle valve as the target throttle valve when the working mode of the heat pump system is the first double-cylinder enthalpy-increasing mode or the second double-cylinder enthalpy-increasing mode. In this way, when the heat pump system operates in the single-cylinder mode or the double-cylinder normal mode, the heat pump system only performs throttling once, at this time the first throttle valve is bypassed, and the exhaust gas of the variable displacement compressor can meet the refrigerant evaporation requirement after being condensed by the condenser and throttled once. Therefore, the embodiment of the present disclosure can adaptively adjust the opening degree of the second throttle valve according to the exhaust gas temperature of the variable displacement compressor, so as to reasonably control the exhaust gas temperature under the premise of meeting the refrigerant evaporation requirement, which is beneficial to the stable operation of the heat pump system. When the heat pump system operates in the first double-cylinder enthalpy-increasing mode or the second double-cylinder enthalpy-increasing mode, the exhaust gas of the variable displacement compressor is condensed by the condenser and throttled twice to meet the intermediate air charging and evaporator refrigerant requirements. Therefore, the embodiment of the present disclosure can adaptively adjust the opening degree of the first throttle valve according to the exhaust gas temperature of the variable displacement compressor, so as to be able to reasonably adjust the intermediate air charging pressure, so as to avoid that the intermediate air charging pressure is controlled to be too high to cause liquid carrying in air charging or the intermediate air charging pressure is controlled to be too low to cause poor air charging enthalpy-increasing effect. Therefore, the embodiment of the present disclosure can reasonably reduce the exhaust gas temperature of the variable displacement compressor through intermediate air charging, which is beneficial to the stable operation of the heat pump system.

[0113] Optionally, the processor adjusts the opening degree of the target throttle valve according to the exhaust gas temperature of the variable displacement compressor, including: increasing the opening degree of the target throttle valve when the exhaust gas temperature of the variable displacement compressor is greater than a preset exhaust gas temperature. In this way, when the exhaust gas temperature of the variable displacement compressor is greater than the preset exhaust gas temperature, the excessively high exhaust gas temperature will have an adverse effect on the reliability of the compressor motor and compressor pump body parts, which may cause irreversible phenomena such as demagnetization of motor magnet and wear of pump body parts, and the compressor capacity will be obviously attenuated. Therefore, the embodiment of the present disclosure can appropriately increase the opening degree of the first throttle valve or the second throttle valve, so as to increase the system air charging amount and reduce the exhaust gas pressure, so as to reasonably reduce the exhaust gas temperature of the variable displacement compressor, which is beneficial to improving the stability of the heat pump system.

[0114] Optionally, the preset exhaust gas temperature can be set in combination with the actual capacity of the variable displacement compressor. Preferably, the preset exhaust gas temperature is 95℃. The preset exhaust gas temperature can also be adjusted according to external environmental conditions, and can also be set to 94℃ or 96℃ or other arbitrary reasonable values.

[0115] In combination Figure 11As shown, the embodiment of the present disclosure provides a control device 80 for a heat pump system, comprising a processor 81 and a memory 82. Optionally, the device can also comprise a communication interface 83 and a bus 84. Wherein the processor 81, the communication interface 83, the memory 82 can complete the communication among each other through the bus 84. The communication interface 503 can be used for information transmission. The processor 81 can call the logic instructions in the memory 82 to execute the control method for the heat pump system of the above-mentioned embodiment.

[0116] In addition, the logic instructions in the memory 82 described above can be realized in the form of a software function unit and sold or used as an independent product when used, which can be stored in a computer readable storage medium.

[0117] The memory 82 as a kind of computer readable storage medium can be used to store software programs, computer executable programs, such as program instructions / modules corresponding to the method in the embodiment of the present disclosure. The processor 81 executes the program instructions / modules stored in the memory 82, thereby executing function application and data processing, that is, realizing the control method for the heat pump system in the above-mentioned embodiment.

[0118] The memory 82 can include a storage program area and a storage data area, wherein the storage program area can store an operating system and an application program required by at least one function; the storage data area can store data created according to the use of the terminal equipment and the like. In addition, the memory 82 can include a high-speed random access memory, and can also include a non-volatile memory.

[0119] In combination Figure 12 As shown, the embodiment of the present disclosure provides an air conditioner, comprising: an air conditioner body 90, and the above-mentioned control device 80 for a heat pump system. The control device 80 for a heat pump system is installed on the air conditioner body 90. The installation relationship described herein is not limited to placing in the product, but also includes installation connection with other components of the product, including but not limited to physical connection, electrical connection or signal transmission connection, etc. Those skilled in the art can understand that the control device 80 for a heat pump system can be adapted to a feasible product body, and then realize other feasible embodiments.

[0120] The embodiment of the present disclosure provides a computer readable storage medium, which stores computer executable instructions, and the computer executable instructions are set to execute the above-mentioned control method for a heat pump system.

[0121] The above-mentioned computer readable storage medium can be a transitory computer readable storage medium, or a non-transitory computer readable storage medium.

[0122] The technical solutions of the embodiments of the present disclosure can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes one or more instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method disclosed in the embodiments of the present disclosure. The aforementioned storage medium can be a non-transitory storage medium, including: a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various media that can store program codes, or can be a transitory storage medium.

[0123] The above description and drawings sufficiently illustrate the embodiments of the present disclosure to enable one skilled in the art to practice them. Other embodiments can include structural, logical, electrical, process, and other changes. The embodiments represent only a few of the possible variations. Individual components and functions are optional unless explicitly required, and the order of operations can be changed. Parts and features of some embodiments can be included in or replace parts and features of other embodiments. Also, the words used in this application are used only to describe the embodiments and not to limit the claims. As used in the description of the embodiments and the claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. Similarly, the term "and / or" as used in this application refers to any and all possible combinations of one or more associated listed items. In addition, when used in this application, the term "comprise" and its variants "comprises" and / or "comprising" and the like mean the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. Without more limitations, the element defined by the phrase "comprising a" does not exclude the presence of additional identical elements in the process, method, or device including the stated element. In this document, each embodiment focuses on the differences from other embodiments, and the same or similar parts between embodiments can be referred to each other. For the method, product, etc. disclosed in the embodiments, if it corresponds to the method part disclosed in the embodiments, the relevant part can be referred to the description of the method part.

[0124] Those skilled in the art can understand that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized by electronic hardware or a combination of computer software and electronic hardware. Whether the functions are realized in hardware or software depends on the specific application and design constraints of the technical solution. The skilled person can use different methods for each specific application to realize the described functions, but such implementation should not be considered beyond the scope of the embodiments of the present disclosure. The skilled person can clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described system, device and unit can refer to the corresponding processes in the foregoing method embodiments, which will not be repeated here.

[0125] In the embodiments disclosed herein, the disclosed methods, products (including but not limited to devices, equipment, etc.) can be implemented in other ways. For example, the above-described device embodiments are only schematic, for example, the division of the units can only be a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some interface, device or unit, and can be electrical, mechanical or other forms. The units described as separate components can or can not be physically separate, and the components shown as units can or can not be physical units, that is, they can be located in one place, or can be distributed on a plurality of network units. Part or all of the units can be selected according to actual needs to implement the embodiments. In addition, each functional unit in the embodiments of the present disclosure can be integrated in one processing unit, or each unit can be a physically independent unit, or two or more units can be integrated in one unit.

[0126] The computer program instructions can also be loaded onto a computer, other programmable data processing apparatus, or other processing device to cause a series of operational steps to be performed on the computer, other programmable apparatus or other processing device to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide processes for implementing the functions / acts specified in the flowchart and / or block diagram block or blocks.

Claims

1. A heat pump system, characterized by, The heat pump system comprises: a main circulation loop, comprising a variable displacement compressor, a condenser, a first throttle valve, a flash tank, a second throttle valve and an evaporator, which are sequentially connected by refrigerant pipelines to form a loop, the variable displacement compressor comprises an upper cylinder and a lower cylinder, and the variable displacement compressor is provided with a variable displacement port and a supplementary air port; a variable displacement pipeline, one end of which is in communication with the variable displacement port of the variable displacement compressor, and the other end of which is divided into a first branch and a second branch, the first branch is in communication with a suction pipeline of the variable displacement compressor, the first branch is provided with a first control valve, the second branch is in communication with a discharge pipeline of the variable displacement compressor, and the second branch is provided with a second control valve; a supplementary air pipeline, one end of which is in communication with the supplementary air port of the variable displacement compressor, and the other end of which is in communication with the flash tank, and the supplementary air pipeline is provided with a third control valve; a bypass pipeline, one end of which is in communication with a pipeline between the condenser and the first throttle valve, and the other end of which is in communication with a pipeline between the flash tank and the second throttle valve, and the bypass pipeline is provided with a fourth control valve.

2. The heat pump system of claim 1, wherein, The supplementary air port is arranged on the lower cylinder, and the variable displacement compressor further comprises: a one-way valve assembly, which is arranged on the lower cylinder corresponding to the supplementary air port and is used for limiting the one-way flow of refrigerant from the supplementary air pipeline into the lower cylinder.

3. The heat pump system of claim 2, wherein, The one-way valve assembly comprises a one-way valve disc and a one-way valve baffle, the one-way valve disc is arranged at the supplementary air port, the one-way valve baffle comprises a connecting portion and a limiting portion, the connecting portion is arranged above the one-way valve disc and is fixedly connected with the one-way valve disc, and the limiting portion is arranged above the one-way valve disc opposite to the supplementary air port, and the lower end surface of the limiting portion has a gap with the one-way valve disc for limiting the opening of the one-way valve disc.

4. The heat pump system of claim 3, wherein, The lower cylinder is provided with a one-way valve seat, a partition plate is arranged between the upper cylinder and the lower cylinder, the one-way valve seat and the partition plate form a containing cavity, the one-way valve assembly is arranged in the containing cavity, and the distance between the upper end surface of the one-way valve baffle and the upper end surface of the lower cylinder is h, h≤0.1mm.

5. The heat pump system of claim 4, wherein, When the one-way valve assembly is arranged in the containing cavity, the remaining volume in the containing cavity is V0, 0.02mL≤V0≤1mL.

6. The heat pump system of claim 1, wherein, The lower cylinder is provided with a slide groove on the side facing the variable displacement port, and the variable displacement compressor further comprises: a variable displacement slide, which is arranged in the slide groove and is provided with a groove; a pin, which is movably arranged below the variable displacement slide, one end of the pin facing the variable displacement slide is provided with a protrusion, and the protrusion is matched with the groove of the variable displacement slide; an elastic member, which is connected with the pin and enables the pin to move between a free position and a compressed position, wherein when the pin moves to the free position, the protrusion of the pin is engaged with the groove of the variable displacement slide to limit the displacement of the variable displacement slide.

7. The heat pump system of claim 1, wherein, The displacement of the upper cylinder is V1, the displacement of the lower cylinder is V2, and 0.5≤V1 / V2≤0.

8.

8. The heat pump system according to any one of claims 1 to 7, characterized in that, The heat pump system further comprises: a third branch, one end of which is in communication with the supplementary air pipeline, and the other end of which is in communication with the variable displacement pipeline, and the third branch is provided with a fifth control valve.

9. The heat pump system according to any one of claims 1 to 7, wherein: a variable displacement tank is arranged on the variable displacement pipeline; and / or, a supplementary air tank is arranged on the supplementary air pipeline; and / or, a distributor is arranged on the suction pipeline.

10. A control method for a heat pump system, characterized by, The method is applied to the heat pump system according to any one of claims 1 to 9, and the method comprises: obtaining the operating frequency, the discharge pressure and the suction pressure of the variable displacement compressor; According to the operating frequency of the variable displacement compressor, the exhaust pressure and the suction pressure, the working mode of the heat pump system is determined; According to the working mode of the heat pump system, the open and close states of the control valves are configured.

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