Dual-stage compressor, control method of dual-stage compressor and air conditioner

Abstract

The present disclosure relates to a two-stage compressor, a control method of the two-stage compressor and an air conditioner. The two-stage compressor comprises a low-pressure stage assembly, a first adjusting mechanism arranged in the low-pressure stage assembly, a high-pressure stage assembly and a second adjusting mechanism arranged in the high-pressure stage assembly. The first adjusting mechanism and the second adjusting mechanism are configured to be in one of the following working modes: the first adjusting mechanism is configured not to adjust the capacity and the internal pressure ratio of the low-pressure stage assembly, and the second adjusting mechanism is configured to adjust the capacity or the internal pressure ratio of the high-pressure stage assembly; the first adjusting mechanism is configured to adjust the capacity of the low-pressure stage assembly, and the second adjusting mechanism is configured to adjust the capacity or the internal pressure ratio of the high-pressure stage assembly; and the first adjusting mechanism is configured to adjust the internal pressure ratio of the low-pressure stage assembly, and the second adjusting mechanism is configured to adjust the capacity or the internal pressure ratio of the high-pressure stage assembly. The problems of extra power consumption caused by the mismatch of the two-stage internal pressure ratio and the problem of being unable to meet the two-stage high-efficiency operation are solved.

Description

Technical Field

[0001] This disclosure relates to the field of compressor technology, and in particular to a two-stage compressor, a control method for a two-stage compressor, and an air conditioner. Background Technology

[0002] The internal pressure ratio is a crucial geometric characteristic of screw compressors, determining the location of the discharge port and significantly impacting compressor performance. In some related technologies, the compressor does not have an internal pressure ratio regulating valve, but only a capacity regulating valve. However, for single-unit two-stage screw compressors, the pressure ratios at the suction and discharge ports are very large. Poor matching of the pressure ratios of the high and low pressure stages can lead to substantial energy losses. Summary of the Invention

[0003] Some embodiments of this disclosure propose a two-stage compressor, a control method for the two-stage compressor, and an air conditioner to solve problems caused by pressure ratio mismatch and capacity mismatch between the high-pressure stage and the low-pressure stage.

[0004] In one aspect of this disclosure, a two-stage compressor is provided, comprising:

[0005] Low-voltage stage components;

[0006] A first adjustment mechanism is provided in the low-voltage stage component;

[0007] High-voltage stage components; and

[0008] A second adjustment mechanism is provided in the high-voltage stage assembly;

[0009] The first adjustment mechanism and the second adjustment mechanism are configured to either operate in one of the following modes:

[0010] The first adjustment mechanism is configured not to adjust the capacity and internal pressure ratio of the low-pressure stage component, and the second adjustment mechanism is configured to adjust the capacity or internal pressure ratio of the high-pressure stage component.

[0011] The first regulating mechanism is configured to regulate the capacity of the low-voltage stage component, and the second regulating mechanism is configured to regulate the capacity or internal pressure ratio of the high-voltage stage component; and

[0012] The first adjustment mechanism is configured to adjust the internal pressure ratio of the low-pressure stage component, and the second adjustment mechanism is configured to adjust the capacity or internal pressure ratio of the high-pressure stage component.

[0013] In some embodiments, the first regulating mechanism includes a first slide valve, the low-pressure stage assembly includes a first screw rotor, and the length of the first slide valve is greater than or equal to the length of the first screw rotor.

[0014] In some embodiments, the first end of the first screw rotor is close to the intake side of the low-pressure stage assembly, and the second end of the first screw rotor is close to the exhaust side of the low-pressure stage assembly; in the state where the low-pressure stage assembly has the largest capacity and the largest internal pressure ratio: the first end of the first slide valve is aligned with the first end of the first screw rotor, the second end of the first slide valve is provided with a first radial exhaust port, and the first radial exhaust port is connected to the second end of the first screw rotor.

[0015] In some embodiments, the critical state is defined as the state in which the low-pressure stage component has the largest capacity and the largest internal pressure ratio: the first slide valve is configured to move toward the intake side of the low-pressure stage component to adjust the internal pressure ratio of the low-pressure stage component; the first slide valve is configured to move toward the exhaust side of the low-pressure stage component to adjust the capacity of the low-pressure stage component.

[0016] In some embodiments, the first end of the first slide valve is configured to have a contact area with the second end of the first screw rotor of at least 5% of the length of the first slide valve, and the low-pressure stage assembly is started up and operated at zero load.

[0017] In some embodiments, the second regulating mechanism includes a second slide valve, the high-pressure stage assembly includes a second screw rotor, and the length of the second slide valve is greater than or equal to the length of the second screw rotor.

[0018] In some embodiments, the first end of the second screw rotor is close to the air inlet side of the high-pressure stage assembly, and the second end of the second screw rotor is close to the exhaust side of the high-pressure stage assembly; in the state where the high-pressure stage assembly has the largest capacity and the largest internal pressure ratio: the first end of the second slide valve is aligned with the first end of the second screw rotor, the second end of the second slide valve is provided with a second radial exhaust port, and the second radial exhaust port is connected to the second end of the second screw rotor.

[0019] In some embodiments, the critical state is defined as the state in which the capacity and internal pressure ratio of the high-pressure stage assembly are at their maximum: the second slide valve is configured to move toward the intake side of the high-pressure stage assembly to adjust the internal pressure ratio of the high-pressure stage assembly; the second slide valve is configured to move toward the exhaust side of the high-pressure stage assembly to adjust the capacity of the high-pressure stage assembly.

[0020] In some embodiments, the first end of the second slide valve is configured to have a contact area with the second end of the second screw rotor of at least 5% of the length of the second slide valve, and the high-pressure stage assembly is started and operated at zero load.

[0021] In some embodiments, the two-stage compressor further includes:

[0022] A first sensor is located at the air inlet of the two-stage compressor and is configured to detect the pressure at the air inlet of the two-stage compressor.

[0023] A second sensor is located between the low-pressure stage assembly and the high-pressure stage assembly and is configured to detect the pressure in the intermediate chamber of the two-stage compressor.

[0024] A third sensor is located at the exhaust port of the two-stage compressor and configured to detect the pressure at the exhaust port of the two-stage compressor; and

[0025] The controller is electrically connected to the first sensor, the second sensor, and the third sensor. The controller is configured to use the ratio of the pressure value detected by the second sensor to the pressure value detected by the first sensor as the actual low-pressure stage internal pressure ratio, and the ratio of the pressure value detected by the third sensor to the pressure value detected by the second sensor as the actual high-pressure stage internal pressure ratio. The controller also compares the actual low-pressure stage internal pressure ratio with the theoretical low-pressure stage internal pressure ratio and sends a signal to control the movement of the first slide valve. Furthermore, the controller compares the actual high-pressure stage internal pressure ratio with the theoretical high-pressure stage internal pressure ratio and sends a signal to control the movement of the second slide valve.

[0026] In some embodiments, the controller is configured to, while controlling the first slide valve to adjust the internal pressure ratio of the low-pressure stage assembly, control the first slide valve to remain stationary when the actual low-pressure stage internal pressure ratio is equal to the theoretical low-pressure stage internal pressure ratio, control the first slide valve to move towards the exhaust side of the low-pressure stage assembly when the actual low-pressure stage internal pressure ratio is less than the theoretical low-pressure stage internal pressure ratio, and control the first slide valve to move towards the intake side of the low-pressure stage assembly when the actual low-pressure stage internal pressure ratio is greater than the theoretical low-pressure stage internal pressure ratio.

[0027] In some embodiments, the controller is configured to, while controlling the second slide valve to adjust the internal pressure ratio of the high-pressure stage assembly, control the second slide valve to remain stationary when the actual internal pressure ratio of the high-pressure stage is equal to the theoretical internal pressure ratio of the high-pressure stage; control the second slide valve to move towards the exhaust side of the high-pressure stage assembly when the actual internal pressure ratio of the high-pressure stage is less than the theoretical internal pressure ratio of the high-pressure stage; and control the second slide valve to move towards the intake side of the high-pressure stage assembly when the actual internal pressure ratio of the high-pressure stage is greater than the theoretical internal pressure ratio of the high-pressure stage.

[0028] In one aspect of this disclosure, a control method for a two-stage compressor is provided, wherein during the operation of the two-stage compressor, one of the following controls is selectively performed:

[0029] The first regulating mechanism is controlled not to adjust the capacity and internal pressure ratio of the low-pressure stage component, while the second regulating mechanism is controlled to adjust the capacity or internal pressure ratio of the high-pressure stage component.

[0030] The first regulating mechanism is controlled to adjust the capacity of the low-voltage stage component, and the second regulating mechanism is controlled to adjust the capacity or internal pressure ratio of the high-voltage stage component; and

[0031] The first regulating mechanism is controlled to adjust the internal pressure ratio of the low-pressure stage component, and the second regulating mechanism is controlled to adjust the capacity or internal pressure ratio of the high-pressure stage component.

[0032] In some embodiments, the first regulating mechanism includes a first slide valve, and the low-pressure stage assembly includes a first screw rotor; a first end of the first screw rotor is close to the intake side of the low-pressure stage assembly, and a second end of the first screw rotor is close to the exhaust side of the low-pressure stage assembly.

[0033] The first end of the first slide valve is aligned with the first end of the first screw rotor, and the first radial exhaust port at the second end of the first slide valve is connected to the second end of the first screw rotor, so that the low-pressure stage assembly is in a state of maximum capacity and maximum internal pressure ratio.

[0034] In some embodiments, the critical state is defined as the low-pressure stage component being in a state with maximum capacity and maximum internal pressure ratio:

[0035] Control the first slide valve to move towards the intake side of the low-pressure stage assembly to adjust the internal pressure ratio of the low-pressure stage assembly; or

[0036] The first slide valve is controlled to move toward the exhaust side of the low-pressure stage assembly to adjust the capacity of the low-pressure stage assembly.

[0037] In some embodiments, the first end of the first slide valve is controlled to have a contact area of ​​at least 5% of the length of the first slide valve with the second end of the first screw rotor, so that the low-pressure stage assembly can start up and operate under zero load.

[0038] In some embodiments, in the operating mode of controlling the first slide valve to adjust the internal pressure ratio of the low-pressure stage component, when the actual internal pressure ratio of the low-pressure stage is equal to the theoretical internal pressure ratio of the low-pressure stage, the first slide valve is controlled to remain stationary; when the actual internal pressure ratio of the low-pressure stage is less than the theoretical internal pressure ratio of the low-pressure stage, the first slide valve is controlled to move towards the exhaust side of the low-pressure stage component; when the actual internal pressure ratio of the low-pressure stage is greater than the theoretical internal pressure ratio of the low-pressure stage, the first slide valve is controlled to move towards the intake side of the low-pressure stage component.

[0039] In some embodiments, the second regulating mechanism includes a second slide valve, and the high-pressure stage assembly includes a second screw rotor; a first end of the second screw rotor is close to the intake side of the high-pressure stage assembly, and a second end of the second screw rotor is close to the exhaust side of the high-pressure stage assembly;

[0040] The first end of the second slide valve is aligned with the first end of the second screw rotor, and the second radial exhaust port provided at the second end of the second slide valve is connected to the second end of the second screw rotor, so that the high-pressure stage assembly is in a state of maximum capacity and maximum internal pressure ratio.

[0041] In some embodiments, the critical state is defined as the state in which the high-voltage stage component is at its maximum capacity and maximum internal pressure ratio.

[0042] Control the second slide valve to move towards the intake side of the high-pressure stage assembly to adjust the internal pressure ratio of the high-pressure stage assembly; or

[0043] The second slide valve is controlled to move toward the exhaust side of the high-pressure stage assembly to adjust the capacity of the high-pressure stage assembly.

[0044] In some embodiments, the first end of the second slide valve is controlled to have a contact area of ​​at least 5% of the length of the second slide valve with the second end of the second screw rotor, so that the high-voltage stage assembly can start-up operation under zero load.

[0045] In some embodiments, when the second slide valve is controlled to adjust the internal pressure ratio of the high-pressure stage assembly, the second slide valve is kept stationary when the actual internal pressure ratio of the high-pressure stage is equal to the theoretical internal pressure ratio of the high-pressure stage; when the actual internal pressure ratio of the high-pressure stage is less than the theoretical internal pressure ratio of the high-pressure stage, the second slide valve is moved toward the exhaust side of the high-pressure stage assembly; and when the actual internal pressure ratio of the high-pressure stage is greater than the theoretical internal pressure ratio of the high-pressure stage, the second slide valve is moved toward the intake side of the high-pressure stage assembly.

[0046] In some embodiments, the theoretical low-pressure stage internal pressure ratio ε of the low-pressure stage component is set. 11 For fixed values,

[0047] According to ε 11 =P / P s , ε 21 =P d / P,

[0048] Obtain ε 21 =P d / (P s *ε 11 ),

[0049] Where, ε 21 This is the theoretical high-pressure stage internal pressure ratio of the high-pressure stage component;

[0050] P s P is the theoretical pressure at the inlet of the two-stage compressor. d P represents the theoretical pressure at the discharge port of the two-stage compressor. Since the operating conditions of a two-stage compressor fluctuate within a preset range during actual operation, P... dand P s The range of values ​​for can be determined.

[0051] In some embodiments, the theoretical low-pressure stage internal pressure ratio ε is defined. 11 The value range is [2.17, 4.8], and the calculated theoretical high-pressure stage internal pressure ratio ε is limited. 21 The value is valid within the range of [2.17, 4.8].

[0052] In some embodiments, according to ε 11＝ P / P s , ε 21＝ P d / P, to obtain the theoretical low-pressure stage internal pressure ratio ε of the low-pressure stage component. 11 and the theoretical high-pressure stage internal pressure ratio ε of the high-pressure stage assembly. 21 ;

[0053] Among them, P s P is the theoretical pressure at the inlet of the two-stage compressor. d Let P be the theoretical pressure at the discharge port of the two-stage compressor, and P be the theoretical pressure in the intermediate chamber of the two-stage compressor, where P = (P... s xP d ) 1 / 2 Because the operating conditions of a two-stage compressor fluctuate within a preset range during actual operation, therefore, P d and P s The range of values ​​for can be determined.

[0054] In one aspect of this disclosure, an air conditioner is provided, including the aforementioned two-stage compressor.

[0055] Based on the above technical solution, this disclosure has at least the following beneficial effects:

[0056] In some embodiments, the low-pressure stage and high-pressure stage components of a two-stage compressor can achieve coupling of pressure ratio, coupling of pressure ratio and capacity, or coupling of capacity, ultimately achieving optimal matching of the two-stage operating conditions. Specifically, by adjusting the pressure ratio of the high-pressure and low-pressure stages, the problem of additional power consumption caused by the mismatch of the internal pressure ratios of the two stages in the two-stage compressor is solved; the problem that a fixed internal pressure ratio in either the two stages or a single stage cannot meet the requirements for efficient two-stage operation when the engineering water temperature varies is also solved; and by adjusting the capacity of the high-pressure and low-pressure stages, the problem of overcurrent protection caused by load start-up in two-stage compressors is solved. Attached Figure Description

[0057] The accompanying drawings, which are included to provide a further understanding of this disclosure and form part of this disclosure, illustrate exemplary embodiments of the present disclosure and are used to explain the disclosure, but do not constitute an undue limitation of the disclosure. In the drawings:

[0058] Figure 1 This is a schematic diagram of a first operating mode of a two-stage compressor provided according to some embodiments of the present disclosure;

[0059] Figure 2 This is a schematic diagram of a second operating mode of a two-stage compressor provided according to some embodiments of the present disclosure;

[0060] Figure 3 This is a schematic diagram of a third operating mode of a two-stage compressor provided according to some embodiments of the present disclosure;

[0061] Figure 4 This is a flowchart illustrating a control method for a two-stage compressor provided according to some embodiments of the present disclosure.

[0062] The labels in the attached diagram are explained as follows:

[0063] 1-Low-voltage stage assembly; 11-First screw rotor;

[0064] 2-High voltage stage assembly; 21-Second screw rotor;

[0065] 3-First adjusting mechanism; 31-First slide valve; 32-First cylinder; 33-First piston; 34-First valve; 311-First radial exhaust port;

[0066] 4-Second adjusting mechanism; 41-Second slide valve; 42-Second cylinder; 43-Second piston; 44-Second valve; 411-Second radial exhaust port;

[0067] 51-First sensor; 52-Second sensor; 53-Third sensor;

[0068] 6-Controller;

[0069] 7-Motor.

[0070] It should be understood that the dimensions of the various parts shown in the accompanying drawings are not drawn to actual scale. Furthermore, the same or similar reference numerals denote the same or similar components. Detailed Implementation

[0071] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The descriptions of the exemplary embodiments are merely illustrative and are in no way intended to limit the present disclosure or its application or use. The present disclosure may be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided so that the present disclosure will be thorough and complete, and will fully express the scope of the disclosure to those skilled in the art. It should be noted that, unless specifically stated otherwise, the relative arrangement of components and steps, the composition of materials, numerical expressions, and values ​​set forth in these embodiments should be interpreted as exemplary only and not as limiting.

[0072] The terms "first," "second," and similar words used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different parts. Words such as "including" or "contains" mean that the element preceding the word encompasses the element listed after it, and do not exclude the possibility of encompassing other elements as well. Terms such as "above," "below," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, this relative positional relationship may also change accordingly.

[0073] In this disclosure, when a specific device is described as being located between a first device and a second device, an intermediary device may or may not be present between the specific device and the first or second device. When a specific device is described as being connected to other devices, the specific device may be directly connected to the other devices without an intermediary device, or it may be not directly connected to the other devices but have an intermediary device.

[0074] All terms used in this disclosure (including technical or scientific terms) have the same meaning as understood by one of ordinary skill in the art to which this disclosure pertains, unless otherwise specifically defined. It should also be understood that terms defined in a general dictionary, such as a dictionary, should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and not as having an idealized or highly formalized meaning, unless expressly defined herein.

[0075] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0076] refer to Figure 1 , Figure 2 and Figure 3 In some embodiments, the two-stage compressor includes a low-pressure stage assembly 1, a high-pressure stage assembly 2, a first regulating mechanism 3, and a second regulating mechanism 4.

[0077] The first regulating mechanism 3 is located in the low-voltage stage component 1; the second regulating mechanism 4 is located in the high-voltage stage component 2.

[0078] The first regulating mechanism 3 and the second regulating mechanism 4 are configured to either operate in one of the following modes:

[0079] The first regulating mechanism 3 is configured not to regulate the capacity and internal pressure ratio of the low-pressure stage component 1, and the second regulating mechanism 4 is configured to regulate the capacity or internal pressure ratio of the high-pressure stage component 2.

[0080] The first regulating mechanism 3 is configured to regulate the capacity of the low-pressure stage component 1, and the second regulating mechanism 4 is configured to regulate the capacity or internal pressure ratio of the high-pressure stage component 2; and

[0081] The first regulating mechanism 3 is configured to regulate the internal pressure ratio of the low-pressure stage component 1, and the second regulating mechanism 4 is configured to regulate the capacity or internal pressure ratio of the high-pressure stage component 2.

[0082] In the above embodiments, the two-stage compressor is controlled by adjusting the pressure ratio and capacity of the low-pressure stage component 1 and the high-pressure stage component 2.

[0083] In the first adjustment method, the first adjustment mechanism 3 does not adjust the capacity and internal pressure ratio of the low-pressure stage component 1; instead, the high-pressure stage component 2 is adjusted solely by the second adjustment mechanism 4. This means that the second adjustment mechanism 4 can adjust the capacity of the high-pressure stage component 2 to achieve two-stage capacity matching adjustment between the high-pressure and low-pressure stages, or it can adjust the pressure ratio of the high-pressure stage component 2 to achieve two-stage pressure ratio matching adjustment between the high-pressure and low-pressure stages. Neither of these implementations affects the total intake air volume of the compressor, because the capacity and internal pressure ratio of the low-pressure stage component 1 remain unchanged; the total intake air volume of the compressor depends on the low-pressure stage.

[0084] In the first regulation method, the load regulation of the two-stage compressor can be achieved by adjusting the compressor motor speed.

[0085] In the second adjustment method, the pressure ratio of the low-pressure stage component 1 is adjusted by the first adjustment mechanism 3 (while the intake air volume remains unchanged), and then the high-pressure stage component 2 is coupled and adjusted by the second adjustment mechanism 4. The implementation method allows for capacity adjustment of the high-pressure stage component 2 via the second adjustment mechanism 4, achieving coupled adjustment of the pressure ratio and capacity of the high-pressure and low-pressure stages. Alternatively, the pressure ratio of the high-pressure stage component 2 can be adjusted via the second adjustment mechanism 4, achieving matched adjustment of the pressure ratio of the high-pressure and low-pressure stages. Compared to the first adjustment method, the second adjustment method offers greater flexibility and is less difficult to adjust.

[0086] In the second regulation method, compressor load regulation can be achieved through the compressor motor speed.

[0087] In the third adjustment method, the capacity of the low-pressure stage component 1 is adjusted by the first adjustment mechanism 3, and then the high-pressure stage component 2 is coupled and adjusted by the second adjustment mechanism 4. The implementation method can achieve two-stage capacity matching adjustment of the high-pressure stage and low-pressure stage by adjusting the capacity of the high-pressure stage component 2 through the second adjustment mechanism 4, or it can achieve two-stage capacity and pressure ratio coupling adjustment of the high-pressure stage and low-pressure stage by adjusting the pressure ratio of the high-pressure stage component 2 through the second adjustment mechanism 4. Compared with the above two adjustment methods, the third adjustment method will affect the total intake air volume of the compressor.

[0088] The compressor load regulation in the third regulation method is achieved directly through the capacity regulation of the low-pressure stage component 1.

[0089] The above three coupling adjustment methods can be coupling between pressure ratios, coupling between pressure ratio and capacity, or coupling between capacity, and can ultimately achieve optimal matching of two operating conditions.

[0090] In some embodiments, by adjusting the pressure ratio of the high-pressure stage and the low-pressure stage, the internal pressure ratio can be quickly brought to the optimal range, reducing energy consumption and enabling the compressor to operate efficiently. This also broadens the operating range for optimal energy efficiency, making it suitable not only for conditions with small temperature fluctuations but also for conditions with large temperature fluctuations such as sudden cooling or heating. The optimal internal pressure ratio can be quickly achieved through the coupled adjustment of the internal pressure ratios of the high-pressure stage and the low-pressure stage, resulting in optimal energy efficiency. This provides a wider range of applications, high adjustment efficiency, and solves the problem of additional power consumption caused by the mismatch of the internal pressure ratios of the two stages in a two-stage compressor. Furthermore, it addresses the issue that a fixed internal pressure ratio in either the two stages or a single stage cannot meet the requirements for efficient two-stage operation when the engineering water temperature varies.

[0091] In some embodiments, by adjusting the capacity of the high-pressure stage and the low-pressure stage, the compressor can achieve smooth zero-load start-up, reduce additional power consumption, improve compressor efficiency, reduce compressor noise, and solve the problem of overcurrent protection caused by load start-up in two-stage compressors. Furthermore, the capacity is adjusted according to load demand, which can meet different temperature requirements set by the user. The coupled capacity adjustment of the high-pressure stage and the low-pressure stage can more quickly adapt to changes in operating conditions, match the internal pressure ratio, and enable the compressor to operate efficiently.

[0092] In some embodiments, by coupling the capacity and internal pressure ratio of the high-pressure stage and the low-pressure stage, the user's demand for cooling capacity can be quickly met by adjusting the capacity, and the internal pressure ratio can be matched with the capacity by adjusting the internal pressure ratio, so as to achieve the best energy efficiency, enable the compressor to operate efficiently, and reduce energy consumption.

[0093] In some embodiments, the first regulating mechanism 3 includes a first slide valve 31, and the low-pressure stage assembly 1 includes a first screw rotor 11, wherein the length of the first slide valve 31 is greater than or equal to the length of the first screw rotor 11.

[0094] In the above embodiment, the length of the first slide valve 31 is greater than or equal to the length of the first screw rotor 11. The first slide valve 31 can be fully matched with the first screw rotor 11 in the length extension direction, so that the first screw rotor 11 can participate in the compression work along its entire length, thereby improving working efficiency.

[0095] If the length of the first slide valve 31 is less than the length of the first screw rotor 11, although the maximum capacity can be achieved when the first slide valve 31 is aligned with the air intake side of the first screw rotor 11, the air intake side of the first screw rotor 11 will not have a corresponding first slide valve 31 because the length of the first slide valve 31 is less than the length of the first screw rotor 11, thus reducing the value of the maximum internal pressure ratio. When the first slide valve 31 is aligned with the air intake side of the first screw rotor 11, the air intake side of the first screw rotor 11 will be bypassed because the length of the first slide valve 31 is less than the length of the first screw rotor 11, reducing the value of the maximum capacity and the value of the maximum internal pressure ratio. Therefore, if the length of the first slide valve 31 is less than the length of the first screw rotor 11, the first screw rotor 11 cannot participate in the compression work along its full length, reducing the working efficiency.

[0096] When the low-pressure stage component 1 has the largest capacity and the largest internal pressure ratio, the first slide valve 31 moves towards the intake side of the first screw rotor 11, which can adjust the internal pressure ratio of the low-pressure stage component 1. The first slide valve 31 moves towards the exhaust side of the first screw rotor 11, which can adjust the capacity of the low-pressure stage component 1. Therefore, the first slide valve 31 can be moved towards the intake or exhaust side as needed to adjust the internal pressure ratio or capacity of the low-pressure stage component 1, so that the internal pressure ratio or capacity of the low-pressure stage component 1 is within the optimal range, reducing energy consumption. Moreover, it is not necessary to replace the slide valve with a different radial exhaust port to meet the adjustment requirements of the internal pressure ratio or capacity, which has the effect of saving costs and improving efficiency.

[0097] In some embodiments, the first end of the first screw rotor 11 is close to the intake side of the low-pressure stage assembly 1, and the second end of the first screw rotor 11 is close to the exhaust side of the low-pressure stage assembly 1.

[0098] refer to Figure 1 When the low-pressure stage component 1 has the largest capacity and the largest internal pressure ratio: the first end of the first slide valve 31 is aligned with the first end of the first screw rotor 11, and the second end of the first slide valve 31 is provided with a first radial exhaust port 311, which is connected to the second end of the first screw rotor 11.

[0099] In the above embodiment, the first end of the first slide valve 31 is aligned with the first end of the first screw rotor 11, and the air inlet of the first screw rotor 11 is the first end of the first screw rotor 11, resulting in the largest air intake. The second end of the first screw rotor 11 is connected to the first radial exhaust port 311, and the second end of the first screw rotor 11 is the exhaust port. Therefore, the entire first screw rotor 11 can participate in compression, resulting in the largest internal pressure ratio and the largest capacity, thus improving working efficiency. Furthermore, the first slide valve 31 does not have redundant length, resulting in a compact structure and reduced cost.

[0100] In this embodiment, the internal pressure ratio adjustment of the low-pressure stage component 1 is achieved by adjusting the position of the first radial exhaust port 311. Specifically, by moving the first slide valve 31 towards the intake side of the first screw rotor 11, the position of the first radial exhaust port 311 is adjusted, thereby adjusting the internal pressure ratio of the low-pressure stage component 1. During the internal pressure ratio adjustment process, the gas volume inside the first screw rotor 11 remains constant. The capacity adjustment of the low-pressure stage component 1 is achieved by adjusting the position of the intake port of the first screw rotor 11. Specifically, by moving the first slide valve 31 towards the exhaust side of the first screw rotor 11, the position of the intake port of the first screw rotor 11 is adjusted, thereby adjusting the capacity of the low-pressure stage component 1. The adjustment concerns the volume of gas entering the first screw rotor 11.

[0101] Therefore, the first slide valve 31 can be moved to the intake or exhaust side as needed to change the position of the first radial exhaust port 311 of the first slide valve 31 or to change the position of the air inlet of the first screw rotor 11, thereby realizing the internal pressure ratio or capacity adjustment of the low-pressure stage component 1, so that the internal pressure ratio or capacity of the low-pressure stage component 1 is within the preferred range, thereby reducing energy consumption. Moreover, it is not necessary to replace the slide valve with a different radial exhaust port to meet the adjustment requirements of the internal pressure ratio or capacity, which has the effect of saving costs and improving efficiency.

[0102] In some embodiments, reference Figure 1 The critical state is defined as the condition where the low-voltage stage component 1 has the largest capacity and the largest internal pressure ratio: (Refer to...) Figure 2 The first slide valve 31 is configured to move toward the intake side of the low-pressure stage assembly 1 to adjust the internal pressure ratio of the low-pressure stage assembly 1; Reference Figure 3 The first slide valve 31 is configured to move toward the exhaust side of the low-pressure stage assembly 1 to adjust the capacity of the low-pressure stage assembly 1.

[0103] In the above embodiment, the state in which the low-pressure stage component 1 has the largest capacity and the largest internal pressure ratio is the critical state. At this time, the position corresponding to the first slide valve 31 is the critical position. Based on the critical position, the first slide valve 31 is moved towards the intake side to adjust the internal pressure ratio, and the first slide valve 31 is moved towards the outlet side to adjust the capacity. The control logic is clear.

[0104] In the above embodiment, when the low-pressure stage component 1 has the largest capacity and the largest internal pressure ratio, the first slide valve 31 is moved toward the air intake side of the low-pressure stage component 1, which adjusts the position of the first radial exhaust port 311. Therefore, the internal pressure ratio of the low-pressure stage component 1 can be adjusted. When the first slide valve 31 is moved toward the exhaust side of the low-pressure stage component 1, the first end of the first slide valve 31 avoids the first end of the first screw rotor 11, which changes the air intake of the first screw rotor 11. Therefore, the capacity of the low-pressure stage component 1 can be adjusted. In summary, the first slide valve 31 can be moved to the intake or exhaust side as needed to change the position of the first radial exhaust port 311 of the first slide valve 31 or to change the position of the air inlet of the first screw rotor 11, thereby realizing the internal pressure ratio or capacity adjustment of the low-pressure stage component 1. This ensures that the internal pressure ratio or capacity of the low-pressure stage component 1 is within the optimal range, thereby reducing energy consumption. Furthermore, it eliminates the need to replace slide valves with different radial exhaust ports to meet the internal pressure ratio or capacity adjustment requirements, thus saving costs and improving efficiency.

[0105] refer to Figure 3 In some embodiments, the first end of the first slide valve 31 is configured to be substantially aligned with the second end of the first screw rotor 11, and the first end of the first slide valve 31 is configured to have a contact area of ​​at least 5% of the length of the first slide valve 31 with the second end of the first screw rotor 11, and the low-pressure stage assembly 1 starts up and operates at zero load.

[0106] In the above embodiments, the two-stage compressor has a compound adjustment structure. Based on achieving optimal matching of the two-stage pressure ratio, the movement of the first slide valve 31 can enable the low-pressure stage component 1 to start under zero load, and the movement of the second slide valve 41 can enable the high-pressure stage component 2 to start under low load, thereby achieving a smooth low-load start-up of the entire compressor.

[0107] Since the first end of the first slide valve 31 and the second end of the first screw rotor 11 have a contact area of ​​at least 5% of the length of the first slide valve 31, the first slide valve 31 will not completely detach from the rotor cavity of the low-pressure stage assembly 1. When the first slide valve 31 needs to move to the first end (to the right) of the first screw rotor 11, the first slide valve 31 can move smoothly.

[0108] It is important to note that the first end of the first slide valve 31 is substantially aligned with the second end of the first screw rotor 11. This is to enable the low-pressure stage assembly 1 to start operating at zero load. However, the first slide valve 31 cannot completely disengage from the rotor cavity of the low-pressure stage assembly 1. Therefore, there is at least a 5% contact area between the first end of the first slide valve 31 and the second end of the first screw rotor 11. This is because once the slide valve disengages from the rotor cavity, there is no limit to its positioning structure, and the slide valve risks being unable to move back into the rotor cavity to the right. Although the first end of the first slide valve 31 is configured to be substantially aligned with the second end of the first screw rotor 11, with a possible 5% contact area, the low-pressure stage does not form a closed tooth groove based on the tooth profile of the contact area, and the load is considered zero. Therefore, when the compressor is powered on, the low-pressure stage starts near zero load, and the system gradually compresses to form a pressure differential. Then, the slide valve is controlled by a solenoid valve to move to the right under the action of the pressure differential, thus regulating the load (capacity). Once the two-stage slide valve reaches... Figure 2 After reaching the indicated position, you can enter the internal pressure ratio adjustment area, and then press... Figure 4 The process shown is used for internal pressure ratio matching and adjustment.

[0109] In some embodiments, the second regulating mechanism 4 includes a second slide valve 41, the high-pressure stage assembly 2 includes a second screw rotor 21, and the length of the second slide valve 41 is greater than or equal to the length of the second screw rotor 21.

[0110] In the above embodiment, the length of the second slide valve 41 is greater than or equal to the length of the second screw rotor 21. The second slide valve 41 can be fully matched with the second screw rotor 21 in the length extension direction, so that the second screw rotor 21 can participate in the compression work along its entire length, thereby improving working efficiency.

[0111] If the length of the second slide valve 41 is less than the length of the second screw rotor 21, although the maximum capacity can be achieved when the second slide valve 41 is aligned with the intake side of the second screw rotor 21, the exhaust side of the second screw rotor 21 will not have a corresponding second slide valve 41, resulting in a decrease in the maximum internal pressure ratio. When the second slide valve 41 is aligned with the exhaust side of the second screw rotor 21, the intake side of the second screw rotor 21 will be bypassed, resulting in a decrease in both the maximum capacity and the maximum internal pressure ratio. Therefore, if the length of the second slide valve 41 is less than the length of the second screw rotor 21, the second screw rotor 21 cannot participate in the compression work along its full length, reducing working efficiency.

[0112] When the high-pressure stage component 2 has the largest capacity and the largest internal pressure ratio, the second slide valve 41 moves towards the intake side of the second screw rotor 21, which can adjust the internal pressure ratio of the high-pressure stage component 2. The second slide valve 41 moves towards the exhaust side of the second screw rotor 21, which can adjust the capacity of the high-pressure stage component 2. Therefore, the second slide valve 41 can be moved towards the intake or exhaust side as needed to adjust the internal pressure ratio or capacity of the high-pressure stage component 2, so that the internal pressure ratio or capacity of the high-pressure stage component 2 is within the optimal range, reducing energy consumption. Moreover, it is not necessary to replace the slide valve with a different radial exhaust port to meet the adjustment requirements of the internal pressure ratio or capacity, which has the effect of saving costs and improving efficiency.

[0113] In some embodiments, the first end of the second screw rotor 21 is close to the intake side of the high-pressure stage assembly 2, and the second end of the second screw rotor 21 is close to the exhaust side of the high-pressure stage assembly 2.

[0114] When the high-pressure stage component 2 has the largest capacity and the largest internal pressure ratio: the first end of the second slide valve 41 is aligned with the first end of the second screw rotor 21, and the second end of the second slide valve 41 is provided with a second radial exhaust port 411, which is connected to the second end of the second screw rotor 21.

[0115] In the above embodiment, the first end of the second slide valve 41 is aligned with the first end of the second screw rotor 21, and the air inlet of the second screw rotor 21 is the first end of the second screw rotor 21, resulting in the maximum air intake. The second end of the second screw rotor 21 is connected to the second radial exhaust port 411, and the second end of the second screw rotor 21 is the exhaust port. Therefore, the entire second screw rotor 21 can participate in compression, resulting in the maximum internal pressure ratio and the maximum capacity, thus improving working efficiency. Furthermore, the second slide valve 41 does not have redundant length, resulting in a compact structure and reduced cost.

[0116] In this embodiment, the internal pressure ratio adjustment of the high-pressure stage component 2 is achieved by adjusting the position of the second radial exhaust port 411. Specifically, by moving the second slide valve 41 towards the intake side of the second screw rotor 21, the position of the second radial exhaust port 411 is adjusted, thereby adjusting the internal pressure ratio of the high-pressure stage component 2. During the internal pressure ratio adjustment process, the gas volume inside the second screw rotor 21 remains constant. The capacity adjustment of the high-pressure stage component 2 is achieved by adjusting the position of the intake port of the second screw rotor 21. Specifically, by moving the second slide valve 41 towards the exhaust side of the second screw rotor 21, the position of the intake port of the second screw rotor 21 is adjusted, thereby adjusting the capacity of the high-pressure stage component 2. The adjustment concerns the volume of gas entering the second screw rotor 21.

[0117] Therefore, the second slide valve 41 can be moved to the intake or exhaust side as needed to change the position of the second radial exhaust port 411 of the second slide valve 41 or to change the position of the air inlet of the second screw rotor 21, thereby realizing the internal pressure ratio or capacity adjustment of the high-pressure stage component 2, so that the internal pressure ratio or capacity of the high-pressure stage component 2 is within the preferred range, thereby reducing energy consumption. Moreover, it is not necessary to replace the slide valve with a different radial exhaust port to meet the adjustment requirements of the internal pressure ratio or capacity, which has the effect of saving costs and improving efficiency.

[0118] In some embodiments, reference Figure 1 The critical state is defined as the state in which the capacity and internal pressure ratio of high-voltage stage component 2 are at their maximum: (Reference) Figure 2 The second slide valve 41 is configured to move toward the inlet side of the high-pressure stage assembly 2 to adjust the internal pressure ratio of the high-pressure stage assembly 2; Reference Figure 3 The second slide valve 41 is configured to move toward the exhaust side of the high-pressure stage assembly 2 to adjust the capacity of the high-pressure stage assembly 2.

[0119] In the above embodiment, the critical state is the state in which the capacity of the high-pressure stage component 2 is the largest and the internal pressure ratio is the largest. At this time, the position corresponding to the second slide valve 41 is the critical position. Based on the critical position, the second slide valve 41 is moved towards the air intake side to adjust the internal pressure ratio, and the second slide valve 41 is moved towards the air outlet side to adjust the capacity. The control logic is clear.

[0120] In the above embodiments, when the high-pressure stage component 2 is at its maximum capacity and internal pressure ratio, moving the second slide valve 41 towards the intake side of the high-pressure stage component 2 adjusts the position of the second radial exhaust port 411, thus enabling adjustment of the internal pressure ratio of the high-pressure stage component 2. Moving the second slide valve 41 towards the exhaust side of the high-pressure stage component 2 causes the first end of the high-pressure stage component 2 to avoid the first end of the second screw rotor 21, changing the intake port of the second screw rotor 21, thus enabling adjustment of the capacity of the high-pressure stage component 2. In summary, the second slide valve 41 can be moved towards the intake or exhaust side as needed to change the position of the second radial exhaust port 411 of the second slide valve 41 or the intake port position of the second screw rotor 21, thereby achieving adjustment of the internal pressure ratio or capacity of the high-pressure stage component 2. This keeps the internal pressure ratio or capacity of the high-pressure stage component 2 within an optimal range, reducing energy consumption. Furthermore, it eliminates the need to replace slide valves with different radial exhaust ports to meet the adjustment requirements of the internal pressure ratio or capacity, resulting in cost savings and improved efficiency.

[0121] In some embodiments, the first end of the second slide valve 41 is configured to be substantially aligned with the second end of the second screw rotor 21, and the first end of the second slide valve 41 is configured to have a contact area of ​​at least 5% of the length of the second slide valve 41 with the second end of the second screw rotor 11, and the high-pressure stage assembly 2 starts up and operates at zero load.

[0122] In the above embodiment, the two-stage compressor has a compound adjustment structure. Based on achieving optimal matching of the two-stage pressure ratio, the high-pressure stage component 2 is started at low load by moving the second slide valve 41, and the low-pressure stage component 1 is started at zero load by moving the first slide valve 31, thereby achieving a smooth low-load start-up of the entire compressor.

[0123] Since the first end of the second slide valve 41 and the second end of the second screw rotor 21 have a contact area of ​​at least 5% of the length of the second slide valve 41, the second slide valve 41 will not completely detach from the rotor cavity of the high-pressure stage assembly 2. When the second slide valve 41 needs to move to the first end (to the right) of the second screw rotor 21, the second slide valve 41 can move smoothly.

[0124] It is important to note that the first end of the second slide valve 41 is roughly aligned with the second end of the second screw rotor 21 to enable the high-pressure stage assembly 2 to start operating at zero load. However, the second slide valve 41 cannot completely disengage from the rotor cavity of the high-pressure stage assembly 2. Therefore, the first end of the second slide valve 41 and the second end of the second screw rotor 11 have at least a 5% contact area. This is because once the slide valve disengages from the rotor cavity, there is no limit to its positioning structure, and the slide valve risks being unable to move back into the rotor cavity to the right. Although the first end of the second slide valve 41 is configured to be roughly aligned with the second end of the second screw rotor 21, with a possible 5% contact area, the high-pressure stage does not form a closed tooth groove based on the tooth profile of the contact area, and the load is considered zero. Therefore, when the compressor is powered on, the high-pressure stage starts near zero load, and the system gradually compresses to form a pressure differential. Then, the slide valve is controlled by a solenoid valve to move to the right under the action of the pressure differential for load (capacity) regulation. Once the two-stage slide valve reaches... Figure 2 After reaching the indicated position, you can enter the internal pressure ratio adjustment area, and then press... Figure 4 The process shown is used for internal pressure ratio matching and adjustment.

[0125] In some embodiments, the two-stage compressor further includes a first sensor 51, a second sensor 52, a third sensor 53, and a controller 6.

[0126] The first sensor 51 is located at the air inlet of the two-stage compressor, and the first sensor 51 is configured to detect the pressure at the air inlet of the two-stage compressor.

[0127] The second sensor 52 is located between the low-pressure stage assembly 1 and the high-pressure stage assembly 2, and the second sensor 52 is configured to detect the pressure in the intermediate chamber of the two-stage compressor.

[0128] The third sensor 53 is located at the exhaust port of the two-stage compressor, and the third sensor 53 is configured to detect the pressure at the exhaust port of the two-stage compressor.

[0129] The controller 6 is electrically connected to the first sensor 51, the second sensor 52, and the third sensor 53. The controller 6 is configured to use the ratio of the pressure value detected by the second sensor 52 to the pressure value detected by the first sensor 51 as the actual low-pressure stage internal pressure ratio, and the ratio of the pressure value detected by the third sensor 53 to the pressure value detected by the second sensor 52 as the actual high-pressure stage internal pressure ratio; and to compare the actual low-pressure stage internal pressure ratio with the theoretical low-pressure stage internal pressure ratio, thereby issuing a signal to control the movement of the first slide valve 31; and to compare the actual high-pressure stage internal pressure ratio with the theoretical high-pressure stage internal pressure ratio, thereby issuing a signal to control the movement of the second slide valve 41.

[0130] In the above embodiments, by using the first sensor 51, the second sensor 52 and the third sensor 53 to monitor the external pressure, the movement of the first slide valve 31 and the second slide valve 41 can be controlled to achieve the same compression final pressure and exhaust pressure, thus achieving precise matching and control of high and low pressure stages under the same operating conditions.

[0131] refer to Figure 4 In some embodiments, the controller 6 is configured to, while controlling the first slide valve 31 to adjust the internal pressure ratio of the low-pressure stage component 1, control the first slide valve 31 to remain stationary when the actual internal pressure ratio of the low-pressure stage is equal to the theoretical internal pressure ratio of the low-pressure stage; control the first slide valve 31 to move towards the exhaust side of the low-pressure stage component 1 when the actual internal pressure ratio of the low-pressure stage is less than the theoretical internal pressure ratio of the low-pressure stage; and control the first slide valve 31 to move towards the intake side of the low-pressure stage component 1 when the actual internal pressure ratio of the low-pressure stage is greater than the theoretical internal pressure ratio of the low-pressure stage.

[0132] refer to Figure 4 In some embodiments, the controller 6 is configured to, while controlling the second slide valve 41 to adjust the internal pressure ratio of the high-pressure stage assembly 2, keep the second slide valve 41 stationary when the actual internal pressure ratio of the high-pressure stage is equal to the theoretical internal pressure ratio of the high-pressure stage; control the second slide valve 41 to move towards the exhaust side of the high-pressure stage assembly 2 when the actual internal pressure ratio of the high-pressure stage is less than the theoretical internal pressure ratio of the high-pressure stage; and control the second slide valve 41 to move towards the intake side of the high-pressure stage assembly 2 when the actual internal pressure ratio of the high-pressure stage is greater than the theoretical internal pressure ratio of the high-pressure stage.

[0133] In some embodiments, the two-stage compressor further includes a first cylinder 32, a first piston 33, and a first valve 34. The first piston 33 is disposed within the first cylinder 32, and a first piston rod connects the first piston 33 and the first slide valve 31. The rodless chamber of the first cylinder 32 is connected to a first oil passage, and the first valve 34 is disposed on the first oil passage. By controlling the opening degree of the first valve 34, the pressure in the rodless chamber of the first cylinder 32 is controlled, thereby controlling the movement of the first slide valve 31.

[0134] Optionally, the first valve 34 includes a solenoid valve.

[0135] In some embodiments, the two-stage compressor further includes a second cylinder 42, a second piston 44, and a second valve 44. The second piston 44 is disposed within the second cylinder 42, and a second piston rod connects the second piston 44 and the second slide valve 41. The rodless chamber of the second cylinder 42 is connected to a second oil passage, and the second valve 44 is disposed on the second oil passage. By controlling the opening degree of the second valve 44, the pressure in the rodless chamber of the second cylinder 42 is controlled, thereby controlling the movement of the second slide valve 41.

[0136] Optionally, the second valve 44 includes a solenoid valve.

[0137] In some embodiments, the two-stage compressor further includes a motor 7, which is disposed between the low-pressure stage assembly 1 and the high-pressure stage assembly 2. The motor 7 simultaneously drives the first screw rotor 11 connected to the low-pressure stage assembly 1 and the second screw rotor 21 connected to the high-pressure stage assembly 2.

[0138] In the above embodiment, the motor 7 is located between the two-stage screw rotors, and the motor 7 can be cooled by the exhaust gas of the low-pressure stage component 1.

[0139] In some embodiments, the two-stage compressor further includes a motor 7 located on the intake side of the first screw rotor 11 of the low-pressure stage assembly 1, which can utilize intake air cooling.

[0140] In the above embodiment, the two-stage compressor is equipped with an internal pressure ratio regulating slide valve mechanism in both the high-pressure and low-pressure stages. Pressure sensors are arranged at the compressor inlet, outlet, and intermediate cavity to monitor the pressure values ​​at the three locations in real time, calculate the internal pressure ratio of each stage in the low-pressure and high-pressure stages, and control the movement of the slide valve by the opening and closing of the solenoid valve, thereby achieving precise adjustment of the internal pressure ratio of the two stages.

[0141] In some embodiments, the two-stage compressor includes a single-unit two-stage screw compressor.

[0142] Some embodiments of this disclosure also provide a control method for the above-described two-stage compressor, wherein during the operation of the two-stage compressor, the following control is selectively performed:

[0143] The first regulating mechanism 3 is controlled not to adjust the capacity and internal pressure ratio of the low-pressure stage component 1, while the second regulating mechanism 4 is controlled to adjust the capacity or internal pressure ratio of the high-pressure stage component 2.

[0144] The first regulating mechanism 3 adjusts the capacity of the low-pressure stage assembly 1, and the second regulating mechanism 4 adjusts the capacity or internal pressure ratio of the high-pressure stage assembly 2; and

[0145] The first regulating mechanism 3 is controlled to adjust the internal pressure ratio of the low-pressure stage component 1, and the second regulating mechanism 4 is controlled to adjust the capacity or internal pressure ratio of the high-pressure stage component 2.

[0146] In the above embodiments, the control method for a two-stage compressor includes not only simultaneous adjustment of the pressure ratios of the high and low pressure stages, but also a method where one stage is fixed while the pressure ratio of the other stage is adjustable. The method where both stages are simultaneously adjustable offers precise control and enables high-efficiency output under various operating conditions. While the method where one stage is fixed while the pressure ratio of the other stage is adjustable, especially the low-pressure stage being fixed while the high-pressure stage is adjustable, cannot achieve the same high-efficiency output under different operating conditions as the two-stage adjustable pressure ratio method, the deviation is within 3%, which is significantly higher than the two-stage fixed pressure ratio method. Furthermore, it features simpler control logic, lower manufacturing complexity, higher cost-effectiveness, and better versatility.

[0147] In the above embodiments, the control method for a two-stage compressor can achieve optimal matching and precise control of the internal pressure ratio under different operating conditions for the same compressor. Matching the pressure ratios of the two stages reduces additional power consumption, improves compressor efficiency, and reduces compressor noise. Furthermore, regardless of whether the compressor is fixed-frequency or variable-frequency, it can achieve low-load start-up, ensuring a smooth low-load start-up before reaching the specified operating condition; and achieving optimal pressure ratio matching after reaching the specified operating condition.

[0148] In some embodiments, the first regulating mechanism 3 includes a first slide valve 31, and the low-pressure stage assembly 1 includes a first screw rotor 11; the first end of the first screw rotor 11 is close to the intake side of the low-pressure stage assembly 1, and the second end of the first screw rotor 11 is close to the exhaust side of the low-pressure stage assembly 1.

[0149] The first end of the first slide valve 31 is aligned with the first end of the first screw rotor 11, and the first radial exhaust port 311 provided at the second end of the first slide valve 31 is connected to the second end of the first screw rotor 11, so that the low-pressure stage assembly 1 is in the state of maximum capacity and maximum internal pressure ratio.

[0150] In some embodiments, the critical state is defined as the state in which the low-voltage stage component 1 is at its maximum capacity and maximum internal pressure ratio:

[0151] The first slide valve 31 is moved towards the intake side of the low-pressure stage assembly 1 to adjust the internal pressure ratio of the low-pressure stage assembly 1; or

[0152] The first slide valve 31 is controlled to move toward the exhaust side of the low-pressure stage assembly 1 to adjust the capacity of the low-pressure stage assembly 1.

[0153] In some embodiments, the first end of the first slide valve 31 is substantially aligned with the second end of the first screw rotor 11, and the first end of the first slide valve 31 is configured to have a contact area of ​​at least 5% of the length of the first slide valve 31 with the second end of the first screw rotor 11, so that the low-pressure stage assembly 1 can start up and operate at zero load.

[0154] In some embodiments, in the working mode of controlling the first slide valve 31 to adjust the internal pressure ratio of the low-pressure stage component 1, when the actual internal pressure ratio of the low-pressure stage is equal to the theoretical internal pressure ratio of the low-pressure stage, the first slide valve 31 is kept stationary; when the actual internal pressure ratio of the low-pressure stage is less than the theoretical internal pressure ratio of the low-pressure stage, the first slide valve 31 is moved towards the exhaust side of the low-pressure stage component 1; when the actual internal pressure ratio of the low-pressure stage is greater than the theoretical internal pressure ratio of the low-pressure stage, the first slide valve 31 is moved towards the intake side of the low-pressure stage component 1.

[0155] In some embodiments, the second regulating mechanism 4 includes a second slide valve 41, and the high-pressure stage assembly 2 includes a second screw rotor 21; the first end of the second screw rotor 21 is close to the air intake side of the high-pressure stage assembly 2, and the second end of the second screw rotor 21 is close to the exhaust side of the high-pressure stage assembly 2.

[0156] The first end of the second slide valve 41 is aligned with the first end of the second screw rotor 21, and the radial exhaust port at the second end of the second slide valve 41 is connected to the second end of the second screw rotor 21, so that the high-pressure stage assembly 2 is in the state of maximum capacity and maximum internal pressure ratio.

[0157] In some embodiments, the critical state is defined as the state in which the high-voltage stage component 2 is at its maximum capacity and maximum internal pressure ratio.

[0158] The second slide valve 41 is moved towards the intake side of the high-pressure stage assembly 2 to adjust the internal pressure ratio of the high-pressure stage assembly 2; or

[0159] The second slide valve 41 is controlled to move toward the exhaust side of the high-pressure stage assembly 2 to adjust the capacity of the high-pressure stage assembly 2.

[0160] In some embodiments, the first end of the second slide valve 41 is substantially aligned with the second end of the second screw rotor 21, and the first end of the second slide valve 41 is configured to have a contact area with the second end of the second screw rotor 21 of at least 5% of the length of the second slide valve 411, so that the high-voltage stage assembly 2 can be started and operated at zero load.

[0161] In some embodiments, when the second slide valve 41 is controlled to adjust the internal pressure ratio of the high-pressure stage assembly 2, when the actual internal pressure ratio of the high-pressure stage is equal to the theoretical internal pressure ratio of the high-pressure stage, the second slide valve 41 is kept stationary; when the actual internal pressure ratio of the high-pressure stage is less than the theoretical internal pressure ratio of the high-pressure stage, the second slide valve 41 is moved toward the exhaust side of the high-pressure stage assembly 2; and when the actual internal pressure ratio of the high-pressure stage is greater than the theoretical internal pressure ratio of the high-pressure stage, the second slide valve 41 is moved toward the intake side of the high-pressure stage assembly 2.

[0162] In some embodiments of the control method for a two-stage compressor, the low-pressure stage component 1 can be selected with a fixed internal pressure ratio, while the high-pressure stage component 2 can be controlled with an adjustable internal pressure ratio.

[0163] Set the theoretical low-pressure stage internal pressure ratio ε of low-pressure stage component 1. 11 For fixed values,

[0164] According to ε 11 =P / P s , ε 21 =P d / P,

[0165] Obtain ε 21 =P d / (P s *ε 11 ),

[0166] Where, ε 21 The theoretical internal pressure ratio of the high-pressure stage of high-pressure stage component 2;

[0167] P s This is the theoretical pressure at the inlet of the two-stage compressor;

[0168] P d This is the theoretical pressure at the discharge port of the two-stage compressor;

[0169] P is the theoretical pressure of the intermediate chamber of the two-stage compressor.

[0170] Because the operating conditions of a two-stage compressor fluctuate within a preset range during actual operation, therefore, P d and P s The range of values ​​for can be determined.

[0171] In some embodiments, the theoretical low-pressure stage internal pressure ratio ε is defined. 11 The value range is [2.17, 4.8], and the calculated theoretical high-pressure stage internal pressure ratio ε is limited. 21 The value is within the range of [2.17, 4.8].

[0172] In the above embodiments, the low-pressure stage component 1 is selected with a fixed internal pressure ratio, and the high-pressure stage component 2 adopts an adjustable internal pressure ratio control method, which can simplify the control logic, reduce the difficulty of operation, improve the reliability of compressor operation, and reduce costs.

[0173] In some specific embodiments, the low-pressure stage component 1 is selected with a fixed internal pressure ratio, while the high-pressure stage component 2 adopts an adjustable internal pressure ratio.

[0174] According to ε 11 =P / P s , ε 21 =P d / P, ε can be calculated 21 =P d / (P s *ε 11 ).

[0175] Because the operating conditions of a two-stage compressor fluctuate within a certain range during actual operation, namely P d / P s It is a definite and controllable range.

[0176] And ε 11 and ε 21 There is a theoretical design range, generally 2.17≤ε≤4.8.

[0177] Then ε 11 Choose a fixed value, within the range of 2.17 ≤ ε 11 ≤4.8, based on the known P d / P s 2.17≤ε 21 ≤4.8 is used to iterate repeatedly to obtain the optimal ε. 11 The range of values.

[0178] According to ε 21＝ P d / (P s *ε 11 ), to obtain ε 21 .

[0179] ε 21、 ε 11 All values ​​are within the range of [2.17, 4.8], and the value ε is continuously taken within this range. 11 To satisfy ε 21 Also within [2.17,4.8].

[0180] Therefore, ε can be obtained. 11 The optional ground value is used as the theoretical low-pressure stage internal pressure ratio of low-pressure stage component 1 to obtain ε. 21 The selectable value is used as the theoretical low-pressure stage internal pressure ratio of high-pressure stage component 2.

[0181] In some embodiments of the control method for a two-stage compressor, both the low-pressure stage component 1 and the high-pressure stage component 2 can be controlled by an adjustable internal pressure ratio.

[0182] According to ε 11 =P / P s , ε 21 =P d / P, to obtain the theoretical low-pressure stage internal pressure ratio ε of low-pressure stage component 1. 11 And the theoretical high-pressure stage internal pressure ratio ε of high-pressure stage component 2. 21 ;

[0183] Among them, P s This is the theoretical pressure at the inlet of the two-stage compressor;

[0184] P dThis is the theoretical pressure at the discharge port of the two-stage compressor;

[0185] P is the theoretical pressure in the intermediate chamber of the two-stage compressor, where P = (P s x P d ) 1 / 2 .

[0186] Because the operating conditions of a two-stage compressor fluctuate within a preset range during actual operation, therefore, P d and P s The range of values ​​for can be determined.

[0187] Based on the description of the above embodiments, the control method of the two-stage compressor can adopt a control method in which the low-pressure stage component 1 selects a fixed internal pressure ratio and the high-pressure stage component 2 adopts an adjustable internal pressure ratio, or it can adopt a control method in which both the low-pressure stage component 1 and the high-pressure stage component 2 adopt adjustable internal pressure ratios.

[0188] like Figures 1 to 3 As shown, both the low-pressure stage assembly 1 and the high-pressure stage assembly 1 of the compressor are individually equipped with an internal pressure ratio coupling adjustment structure, namely, a slide valve, piston, cylinder, and solenoid valve hydraulic pressure control integrated mechanism. The pressure ratio coupling adjustment requires the critical positions of the two-stage slide valves to move as shown in the diagram. Figure 1 As shown. Moving it further to the left (exhaust side) switches to capacity adjustment. Moving it to the right (intake side) switches to internal pressure ratio adjustment.

[0189] like Figures 1 to 3 As shown, a first sensor 51, a second sensor 52, and a third sensor 53 are respectively installed at the air inlet, intermediate chamber, and exhaust port of the two-stage compressor.

[0190] The first sensor 51 is located at the air inlet of the two-stage compressor and is used to detect the pressure at the air inlet of the two-stage compressor.

[0191] The second sensor 52 is located between the low-pressure stage assembly 1 and the high-pressure stage assembly 2, and is used to detect the pressure in the intermediate chamber of the two-stage compressor.

[0192] The third sensor 53 is located at the exhaust port of the two-stage compressor and is used to detect the pressure at the exhaust port of the two-stage compressor.

[0193] By monitoring pressure changes at various points in real time using pressure sensors, the actual internal pressure ratio ε of the low-pressure stage can be calculated. 12 and the actual internal pressure ε of the high-pressure stage 22 , for respectively: ε 12＝ P m / P s1 , ε 22＝ P d1 / P m .

[0194] Among them, Pm This refers to the actual pressure in the intermediate chamber of the two-stage compressor.

[0195] P s1 This is the actual pressure at the inlet of the two-stage compressor;

[0196] P d1 This is the actual pressure at the discharge port of the two-stage compressor.

[0197] For the theoretical low-pressure stage internal pressure ratio ε 11 The internal pressure ratio ε of the theoretical high-pressure stage 21 It can be calculated according to the formula: ε 11＝ P / P s , ε 21＝ P d / P is obtained through calculation.

[0198] Among them, P s This is the theoretical pressure at the inlet of the two-stage compressor;

[0199] P d This is the theoretical pressure at the discharge port of the two-stage compressor;

[0200] P is the theoretical pressure of the intermediate chamber of the two-stage compressor.

[0201] Because the operating conditions of a two-stage compressor fluctuate within a preset range during actual operation, the theoretical pressures at the suction and discharge ports are already determined when the compressor operates under specified conditions. P d and P s The range of values ​​for can be determined.

[0202] Therefore, the theoretical pressure P in the intermediate cavity can be calculated as P = (P s x P d ) 1 / 2 .

[0203] refer to Figure 4 When the compressor starts running, the theoretical low-pressure stage internal pressure ratio ε has been determined. 11 The internal pressure ratio ε of the theoretical high-pressure stage 21 The actual pressure at the inlet, intermediate chamber, and outlet of the two-stage compressor is monitored in real time by sensors, and the actual low-pressure stage internal pressure ratio ε is calculated. 12 and the actual internal pressure ε of the high-pressure stage 22 .

[0204] The internal pressure ratio determination strategy is as follows:

[0205] In ε 11 =ε 12 ε 21 =ε 22 At this time, the first slide valve 31 and the second slide valve 41 are not activated, and the compressor continues to operate in its original state.

[0206] In ε 11 ≠ε 12 ε 21 ≠ε 22 At that time, the first slide valve 31 and the second slide valve 41 are controlled to operate.

[0207] Among them, in ε 11 >ε 12 At that time, the first slide valve 31 is controlled to move to the left, that is, to move towards the exhaust side of the low-pressure stage assembly 1, until ε 11 =ε 12 .

[0208] In ε 11 <ε 12 At this time, the first slide valve 31 is controlled to move to the right, that is, to move towards the intake side of the low-pressure stage assembly 1, until ε 11 =ε 12 .

[0209] In ε 21 >ε 22 At that time, the second slide valve 31 is controlled to move to the left, that is, to move towards the exhaust side of the high-pressure stage assembly 1, until ε 21 =ε 22 .

[0210] In ε 21 <ε 22 At this time, the second slide valve 31 is controlled to move to the right, that is, to move towards the intake side of the high-pressure stage assembly 2, until ε 21 =ε 22 .

[0211] In the above embodiments, according to ε 11 With ε 12 ε 21 With ε 22 The relationship between the two stages is determined by the two-stage pressure ratio coupling control strategy shown in the diagram, which determines the movement of the slide valves in the low-pressure and high-pressure stages. This is repeated cyclically until ε is reached. 11 =ε 12 ε 21 =ε 22 When the two-stage slide valve reaches its optimal position, the solenoid valve oil pressure control structure stops operating, precisely matching the two-stage pressure ratio, reducing additional power consumption, improving compressor efficiency, and reducing compressor noise.

[0212] The solenoid valve hydraulic control mechanism mainly operates according to logic commands. When the spool valve needs to move to the left, the lubricating oil on the left side of the piston is discharged from the cylinder, causing the spool valve to move to the left. Similarly, when the spool valve needs to move to the right, lubricating oil is introduced into the cylinder on the left side of the piston, pushing the spool valve to the right.

[0213] Furthermore, embodiments of this disclosure also include a pressure ratio coupling adjustment structure set separately for the low-pressure stage or the high-pressure stage, based on ε. 11 With ε 12 ε 21 With ε 22 The relationship between the two stages is that the pressure ratio of the first stage is adjusted to adapt to the pressure ratio of the two stages.

[0214] In some embodiments, the two-stage slide valve is controlled by a solenoid valve to move to the left. Figure 3 The position indicates that the compressor is running under no-load conditions, close to zero-load startup. This is beneficial for selecting the appropriate circuit breaker for the system. Selecting an oversized circuit breaker will result in high costs and be uneconomical.

[0215] It is important to note that neither the high-pressure nor low-pressure stage slide valves can completely detach from the rotor cavity; there must be at least a 5% contact area between the slide valve and the rotor cavity. This is because once the slide valve detaches from the rotor cavity, there is no limit to its position, and it risks failing to move to the right into the rotor cavity. Although there is a 5% contact area, based on the tooth profile of this area, neither stage forms a closed tooth groove, and the load is considered zero. Therefore, when the compressor is powered on, both stages will start under near-zero load. As the system operates and compresses, a pressure differential is gradually built up. Then, the solenoid valve controls the slide valve to move to the right under this pressure differential, thus regulating the load. Once the two-stage slide valves reach... Figure 2 After positioning, you can enter the internal pressure ratio adjustment area and then press... Figure 4 Perform internal pressure ratio matching adjustment.

[0216] Some embodiments of this disclosure also provide an air conditioner that includes the two-stage compressor of any of the above embodiments.

[0217] Based on the embodiments disclosed above, in the absence of explicit denial or conflict, the technical features of one embodiment may be advantageously combined with one or more other embodiments.

[0218] While specific embodiments of this disclosure have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of this disclosure. Those skilled in the art should understand that modifications can be made to the above embodiments or equivalent substitutions can be made to some technical features without departing from the scope and spirit of this disclosure. The scope of this disclosure is defined by the appended claims.

Claims

1. A two-stage compressor, characterized in that, include: Low-voltage stage components (1); The first adjustment mechanism (3) is located on the low-pressure stage component (1). High voltage stage components (2); as well as The second adjustment mechanism (4) is located on the high-voltage stage assembly (2); The first adjustment mechanism (3) and the second adjustment mechanism (4) are configured to either operate in one of the following modes: The first adjustment mechanism (3) is configured not to adjust the capacity and internal pressure ratio of the low-pressure stage component (1), and the second adjustment mechanism (4) is configured to adjust the capacity or internal pressure ratio of the high-pressure stage component (2); The first regulating mechanism (3) is configured to regulate the capacity of the low-pressure stage component (1), and the second regulating mechanism (4) is configured to regulate the capacity or internal pressure ratio of the high-pressure stage component (2); and The first regulating mechanism (3) is configured to regulate the internal pressure ratio of the low-pressure stage component (1), and the second regulating mechanism (4) is configured to regulate the capacity or internal pressure ratio of the high-pressure stage component (2); The first regulating mechanism (3) includes a first slide valve (31), with the state of the low-pressure stage component (1) having the largest capacity and the largest internal pressure ratio as the critical state: the first slide valve (31) is configured to move toward the intake side of the low-pressure stage component (1) to regulate the internal pressure ratio of the low-pressure stage component (1); the first slide valve (31) is configured to move toward the exhaust side of the low-pressure stage component (1) to regulate the capacity of the low-pressure stage component (1).

2. The two-stage compressor according to claim 1, characterized in that, The low-pressure stage assembly (1) includes a first screw rotor (11), and the length of the first slide valve (31) is greater than or equal to the length of the first screw rotor (11).

3. The two-stage compressor according to claim 2, characterized in that, The first end of the first screw rotor (11) is close to the intake side of the low-pressure stage assembly (1), and the second end of the first screw rotor (11) is close to the exhaust side of the low-pressure stage assembly (1). When the low-pressure stage component (1) has the largest capacity and the largest internal pressure ratio: the first end of the first slide valve (31) is aligned with the first end of the first screw rotor (11), the second end of the first slide valve (31) is provided with a first radial exhaust port (311), and the first radial exhaust port (311) is connected to the second end of the first screw rotor (11).

4. The two-stage compressor according to claim 2 or 3, characterized in that, The first end of the first slide valve (31) is configured to have a contact area with the second end of the first screw rotor (11) of at least 5% of the length of the first slide valve (31), and the low-pressure stage assembly (1) is started and operated at zero load.

5. The two-stage compressor according to claim 1, characterized in that, The second regulating mechanism (4) includes a second slide valve (41), and the high-pressure stage assembly (2) includes a second screw rotor (21). The length of the second slide valve (41) is greater than or equal to the length of the second screw rotor (21).

6. The two-stage compressor according to claim 5, characterized in that, The first end of the second screw rotor (21) is close to the air intake side of the high-pressure stage assembly (2), and the second end of the second screw rotor (21) is close to the exhaust side of the high-pressure stage assembly (2). When the high-pressure stage assembly (2) has the largest capacity and the largest internal pressure ratio: the first end of the second slide valve (41) is aligned with the first end of the second screw rotor (21), and the second end of the second slide valve (41) is provided with a second radial exhaust port (411), which is connected to the second end of the second screw rotor (21).

7. The two-stage compressor according to claim 5 or 6, characterized in that, The critical state is defined as the state in which the capacity of the high-pressure stage component (2) is at its maximum and the internal pressure ratio is at its maximum: the second slide valve (41) is configured to move toward the intake side of the high-pressure stage component (2) to adjust the internal pressure ratio of the high-pressure stage component (2); the second slide valve (41) is configured to move toward the exhaust side of the high-pressure stage component (2) to adjust the capacity of the high-pressure stage component (2).

8. The two-stage compressor according to claim 5 or 6, characterized in that, The first end of the second slide valve (41) is configured to have a contact area with the second end of the second screw rotor (21) of at least 5% of the length of the second slide valve (41), and the high-pressure stage assembly (2) is started and operated at zero load.

9. The two-stage compressor according to claim 5 or 6, characterized in that, Also includes: A first sensor (51) is located at the inlet of the two-stage compressor and is configured to detect the pressure at the inlet of the two-stage compressor. A second sensor (52) is located between the low-pressure stage assembly (1) and the high-pressure stage assembly (2) and is configured to detect the pressure in the intermediate chamber of the two-stage compressor; A third sensor (53) is located at the exhaust port of the two-stage compressor and is configured to detect the pressure at the exhaust port of the two-stage compressor. as well as The controller (6) is electrically connected to the first sensor (51), the second sensor (52), and the third sensor (53). The controller (6) is configured to take the ratio of the pressure value detected by the second sensor (52) to the pressure value detected by the first sensor (51) as the actual low-pressure stage internal pressure ratio, and take the ratio of the pressure value detected by the third sensor (53) to the pressure value detected by the second sensor (52) as the actual high-pressure stage internal pressure ratio. The controller (6) also compares the actual low-pressure stage internal pressure ratio with the theoretical low-pressure stage internal pressure ratio and sends a signal to control the movement of the first slide valve (31). The controller (6) also compares the actual high-pressure stage internal pressure ratio with the theoretical high-pressure stage internal pressure ratio and sends a signal to control the movement of the second slide valve (41).

10. The two-stage compressor according to claim 9, characterized in that, The controller (6) is configured to, when controlling the first slide valve (31) to adjust the internal pressure ratio of the low-pressure stage assembly (1), control the first slide valve (31) to remain stationary when the actual internal pressure ratio of the low-pressure stage is equal to the theoretical internal pressure ratio of the low-pressure stage, control the first slide valve (31) to move toward the exhaust side of the low-pressure stage assembly (1) when the actual internal pressure ratio of the low-pressure stage is less than the theoretical internal pressure ratio of the low-pressure stage, and control the first slide valve (31) to move toward the intake side of the low-pressure stage assembly (1) when the actual internal pressure ratio of the low-pressure stage is greater than the theoretical internal pressure ratio of the low-pressure stage.

11. The two-stage compressor according to claim 9, characterized in that, The controller (6) is configured to, while controlling the second slide valve (41) to adjust the internal pressure ratio of the high-pressure stage assembly (2), control the second slide valve (41) to remain stationary when the actual internal pressure ratio of the high-pressure stage is equal to the theoretical internal pressure ratio of the high-pressure stage, control the second slide valve (41) to move towards the exhaust side of the high-pressure stage assembly (2) when the actual internal pressure ratio of the high-pressure stage is less than the theoretical internal pressure ratio of the high-pressure stage, and control the second slide valve (41) to move towards the intake side of the high-pressure stage assembly (2) when the actual internal pressure ratio of the high-pressure stage is greater than the theoretical internal pressure ratio of the high-pressure stage.

12. A control method for a two-stage compressor according to any one of claims 1 to 11, characterized in that, During the operation of the two-stage compressor, one of the following controls may be selected: Control the first regulating mechanism (3) not to adjust the capacity and internal pressure ratio of the low-pressure stage component (1), and control the second regulating mechanism (4) to adjust the capacity or internal pressure ratio of the high-pressure stage component (2); The first regulating mechanism (3) is controlled to adjust the capacity of the low-pressure stage component (1), and the second regulating mechanism (4) is controlled to adjust the capacity or internal pressure ratio of the high-pressure stage component (2); and The first regulating mechanism (3) is controlled to regulate the internal pressure ratio of the low-pressure stage component (1), and the second regulating mechanism (4) is controlled to regulate the capacity or internal pressure ratio of the high-pressure stage component (2).

13. The control method for a two-stage compressor according to claim 12, characterized in that, The first regulating mechanism (3) includes a first slide valve (31), and the low-pressure stage assembly (1) includes a first screw rotor (11); the first end of the first screw rotor (11) is close to the intake side of the low-pressure stage assembly (1), and the second end of the first screw rotor (11) is close to the exhaust side of the low-pressure stage assembly (1); The first end of the first slide valve (31) is aligned with the first end of the first screw rotor (11), and the first radial exhaust port (311) provided at the second end of the first slide valve (31) is connected to the second end of the first screw rotor (11) so that the low-pressure stage assembly (1) is in a state of maximum capacity and maximum internal pressure ratio.

14. The control method for a two-stage compressor according to claim 13, characterized in that, The critical state is defined as the low-pressure stage component (1) being in a state with maximum capacity and maximum internal pressure ratio: Control the first slide valve (31) to move towards the intake side of the low-pressure stage assembly (1) to adjust the internal pressure ratio of the low-pressure stage assembly (1); or The first slide valve (31) is controlled to move toward the exhaust side of the low-pressure stage assembly (1) to adjust the capacity of the low-pressure stage assembly (1).

15. The control method for a two-stage compressor according to claim 13, characterized in that, Control the first end of the first slide valve (31) to have a contact area of ​​at least 5% of the length of the first slide valve (31) with the second end of the first screw rotor (11) so that the low-pressure stage assembly (1) can start running under zero load.

16. The control method for a two-stage compressor according to claim 14, characterized in that, In the working mode of controlling the first slide valve (31) to adjust the internal pressure ratio of the low-pressure stage component (1), when the actual internal pressure ratio of the low-pressure stage is equal to the theoretical internal pressure ratio of the low-pressure stage, the first slide valve (31) is controlled to remain stationary; when the actual internal pressure ratio of the low-pressure stage is less than the theoretical internal pressure ratio of the low-pressure stage, the first slide valve (31) is controlled to move towards the exhaust side of the low-pressure stage component (1); when the actual internal pressure ratio of the low-pressure stage is greater than the theoretical internal pressure ratio of the low-pressure stage, the first slide valve (31) is controlled to move towards the intake side of the low-pressure stage component (1).

17. The control method for a two-stage compressor according to claim 12, characterized in that, The second regulating mechanism (4) includes a second slide valve (41), and the high-pressure stage assembly (2) includes a second screw rotor (21); the first end of the second screw rotor (21) is close to the air intake side of the high-pressure stage assembly (2), and the second end of the second screw rotor (21) is close to the exhaust side of the high-pressure stage assembly (2); The first end of the second slide valve (41) is aligned with the first end of the second screw rotor (21), and the second radial exhaust port (411) provided at the second end of the second slide valve (41) is connected to the second end of the second screw rotor (21) so that the high-pressure stage assembly (2) is in a state of maximum capacity and maximum internal pressure ratio.

18. The control method for a two-stage compressor according to claim 17, characterized in that, The critical state is defined as the state in which the high-voltage stage component (2) is at its maximum capacity and maximum internal pressure ratio. Control the second slide valve (41) to move towards the intake side of the high-pressure stage assembly (2) to adjust the internal pressure ratio of the high-pressure stage assembly (2); or The second slide valve (41) is controlled to move toward the exhaust side of the high-pressure stage assembly (2) to adjust the capacity of the high-pressure stage assembly (2).

19. The control method for a two-stage compressor according to claim 17, characterized in that, Control the first end of the second slide valve (41) to have a contact area of ​​at least 5% of the length of the second slide valve (41) with the second end of the second screw rotor (21) so that the high-voltage stage assembly (2) can start running under zero load.

20. The control method for a two-stage compressor according to claim 18, characterized in that, While the second slide valve (41) is controlling the internal pressure ratio of the high-pressure stage assembly (2) to be adjusted, when the actual internal pressure ratio of the high-pressure stage is equal to the theoretical internal pressure ratio of the high-pressure stage, the second slide valve (41) is controlled to remain stationary; when the actual internal pressure ratio of the high-pressure stage is less than the theoretical internal pressure ratio of the high-pressure stage, the second slide valve (41) is controlled to move towards the exhaust side of the high-pressure stage assembly (2); when the actual internal pressure ratio of the high-pressure stage is greater than the theoretical internal pressure ratio of the high-pressure stage, the second slide valve (41) is controlled to move towards the intake side of the high-pressure stage assembly (2).

21. The control method for a two-stage compressor according to claim 12, characterized in that, The theoretical low-pressure stage internal pressure ratio ε of the low-pressure stage component (1) is set. 11 For fixed values, According to ε 11 =P / P s , ε 21 =P d / P, Obtain ε 21 =P d / (P s *ε 11 ), Where, ε 21 The theoretical high-pressure internal pressure ratio of the high-pressure stage component (2); P s P is the theoretical pressure at the inlet of the two-stage compressor. d P is the theoretical pressure at the discharge port of the two-stage compressor, and P is the theoretical pressure in the intermediate chamber of the two-stage compressor. Since the operating conditions of the two-stage compressor fluctuate within a preset range during actual operation, therefore, P... d and P s The range of values ​​for can be determined.

22. The control method for a two-stage compressor according to claim 21, characterized in that, The theoretical low-pressure stage internal pressure ratio ε is limited. 11 The value range is [2.17, 4.8], and the calculated theoretical high-pressure stage internal pressure ratio ε is limited. 21 The value is valid within the range of [2.17, 4.8].

23. The control method for a two-stage compressor according to claim 12, characterized in that, According to ε 11= P / P s , ε 21= P d / P, to obtain the theoretical low-pressure stage internal pressure ratio ε of the low-pressure stage component (1). 11 and the theoretical high-pressure internal pressure ratio ε of the high-pressure stage component (2). 21 ; Among them, P s P is the theoretical pressure at the inlet of the two-stage compressor. d Let P be the theoretical pressure at the discharge port of the two-stage compressor, and P be the theoretical pressure in the intermediate chamber of the two-stage compressor, where P = (P... s x P d ) 1 / 2 Because the operating conditions of a two-stage compressor fluctuate within a preset range during actual operation, therefore, P d and P s The range of values ​​for can be determined.

24. An air conditioner, characterized in that, Includes a two-stage compressor according to any one of claims 1 to 11.

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