Control method, control device, double-compressor parallel structure and air conditioning equipment

Abstract

The invention provides a control method, a control device, a double-compressor parallel structure and air conditioning equipment. The double-compressor parallel structure comprises a first compressor, a second compressor, a first air suction branch and a second air suction branch, a first control valve is arranged on the first air suction branch, and a second control valve is arranged on the second air suction branch. In the starting process of the double-compressor parallel connection structure, when it is detected that one compressor is started and the other compressor is still not started, the pressure difference between the exhaust pressure and the suction pressure of the non-started compressor is reduced by adjusting the opening degree of the control valve corresponding to the non-started compressor, so that the non-started compressor is controlled to be started, and the pressure difference between the exhaust pressure and the suction pressure of the non-started compressor is reduced. Therefore, on-load starting of the non-started compressor can be avoided, smooth starting of the non-started compressor can be better ensured, the risk of damage to the compressor can be reduced, and the reliability and stability of the whole air conditioning equipment to which the double-compressor parallel structure belongs are improved.

Description

Technical Field

[0001] The present disclosure relates to the technical field of air conditioning, and in particular to a control method, a control device, a dual compressor parallel structure and air conditioning equipment. Background Art

[0002] With the rapid development of modern building technology and people's increasing requirements for indoor environmental comfort, air conditioning equipment is increasingly used in various places and plays an extremely critical role. For some large commercial buildings, industrial plants or special function places, the space is large, the staff is dense and the equipment is numerous, which puts extremely stringent requirements on the cooling capacity of air conditioners.

[0003] In the field of air conditioning technology, the traditional single-system single-compressor structure gradually shows its limitations when facing such high cooling capacity requirements. The single compressor has an upper limit on cooling capacity in design, and it is difficult to meet the load requirements in large-scale cooling demand scenarios. In order to effectively meet this challenge, the single-system, dual-compressor structure came into being and has gained widespread attention and application in the market.

[0004] The dual compressor structure has significant advantages over the single compressor. From the perspective of performance improvement, the coordinated operation of two compressors can significantly expand the output range of cooling capacity and better adapt to complex and changing heat load conditions. For example, during the peak business hours of large shopping malls, the flow of people increases dramatically and various electrical equipment are running at the same time, and the indoor heat load rises sharply. The dual compressor structure can flexibly adjust the operating state according to actual needs, quickly and effectively reduce the indoor temperature, and provide a more stable and comfortable environment. From the perspective of economic consumption, the dual compressor structure is not a simple power superposition, and it can show a higher energy efficiency ratio when operating at partial load. In some non-full load operation periods, such as early morning or late night when the mall has less passenger flow, the dual compressor can selectively start one or two compressors according to actual needs and optimize their operating frequency, avoiding the problem of low efficiency of a single compressor under low load conditions, thereby achieving efficient use of energy and reducing long-term operating costs.

[0005] However, despite the many advantages of the dual compressor structure, its parallel structure still has many aspects to be improved at the current technical level. Among them, a very prominent problem is that it is difficult to achieve complete synchronization of the start-up time of the two compressors. In the actual operation process, since the compressor startup process involves multiple complex links such as motor startup, establishment of lubricating oil circulation, suction pressure balance, etc., and is affected by the combined influence of multiple factors such as motor characteristics, control system response speed, and friction differences of mechanical components, it is almost inevitable that one compressor will complete the startup first. When this happens, the compressor that starts first will first establish a refrigerant circulation in the system and begin to bear the load, which will cause the system pressure and refrigerant flow to change instantly. At this time, the other compressor that has not yet started is faced with the dilemma of starting with load. Starting with load may cause the compressor to fail to start smoothly, and will also significantly increase the risk of compressor damage, which will affect the reliability and stability of the entire air-conditioning equipment. Summary of the invention

[0006] In view of this, in order to solve the technical problem in the prior art that one compressor in a dual compressor parallel structure is started first, resulting in the other compressor starting under load, the present disclosure provides a control method, a control device, a dual compressor parallel structure and an air-conditioning device.

[0007] According to a first aspect of an embodiment of the present disclosure, a control method is provided, the control method being applied to a dual compressor parallel structure, the dual compressor parallel structure comprising a first compressor, a second compressor, a first suction branch and a second suction branch, the outlet of the first suction branch being connected to the inlet of the first compressor, the outlet of the second suction branch being connected to the inlet of the second compressor, a first control valve being provided on the first suction branch, and a second control valve being provided on the second suction branch;

[0008] The control method comprises:

[0009] During the startup process of the dual compressor parallel structure, when it is detected that one of the compressors has been started and the other compressor has not been started, the pressure difference between the exhaust pressure and the suction pressure of the target compressor is reduced by adjusting the opening of the target control valve to control the start of the target compressor;

[0010] The target compressor is a compressor that is not started between the first compressor and the second compressor, and the target control valve is a control valve on the suction side of the target compressor between the first control valve and the second control valve.

[0011] In an alternative embodiment,

[0012] The reducing the pressure difference between the exhaust pressure and the suction pressure of the target compressor by adjusting the opening of the target control valve comprises:

[0013] Acquire the current exhaust pressure and the current suction pressure of the target compressor;

[0014] determining a current pressure difference of the target compressor based on the current exhaust pressure and the current suction pressure;

[0015] Based on the current pressure difference, determining the opening adjustment information of the target control valve;

[0016] The opening degree of the target control valve is adjusted based on the opening degree adjustment information to reduce the pressure difference between the discharge pressure and the suction pressure of the target compressor.

[0017] In an alternative embodiment,

[0018] The step of determining the opening adjustment information of the target control valve based on the current pressure difference includes:

[0019] Obtaining a reference suction pressure and a reference exhaust pressure of the target compressor; wherein the reference suction pressure is the suction pressure of the target compressor when the started compressor is not started; the reference exhaust pressure is the exhaust pressure of the target compressor when the started compressor is not started;

[0020] determining a reference pressure difference of the target compressor based on the reference suction pressure and the reference discharge pressure;

[0021] The opening adjustment information is determined based on the current pressure difference and the reference pressure difference.

[0022] In an alternative embodiment,

[0023] The control method comprises:

[0024] After the first compressor and the second compressor have both been running for a set time, determining whether a first oil level of the first compressor and a second oil level of the second compressor are both greater than or equal to a set gear;

[0025] When the first oil level and the second oil level are both greater than or equal to a set gear, determining whether a first operating frequency of the first compressor and a second operating frequency of the second compressor are the same;

[0026] When the first operating frequency is different from the second operating frequency, the opening of the first control valve is adjusted to match the operating frequency of the first compressor with the exhaust pressure of the first compressor, and the opening of the second control valve is adjusted to match the operating frequency of the second compressor with the exhaust pressure of the second compressor.

[0027] In an alternative embodiment,

[0028] The step of adjusting the opening of the first control valve so that the operating frequency of the first compressor matches the exhaust pressure of the first compressor includes:

[0029] Acquire frequency-pressure configuration information of the first compressor; wherein the frequency-pressure configuration information of the first compressor represents a corresponding relationship between mutually matching operating frequencies and exhaust pressures of the first compressor;

[0030] determining a first target exhaust pressure of the first compressor based on the first operating frequency and the frequency-pressure configuration information of the first compressor;

[0031] The opening degree of the first control valve is adjusted so that the exhaust pressure of the first compressor reaches the first target exhaust pressure.

[0032] In an alternative embodiment,

[0033] The step of adjusting the opening of the second control valve so that the operating frequency of the second compressor matches the exhaust pressure of the second compressor includes:

[0034] Acquire frequency-pressure configuration information of the second compressor; wherein the frequency-pressure configuration information of the second compressor represents the corresponding relationship between the mutually matching operating frequency and exhaust pressure of the second compressor;

[0035] determining a second target exhaust pressure of the second compressor based on the second operating frequency and the frequency-pressure configuration information of the second compressor;

[0036] The opening degree of the second control valve is adjusted so that the exhaust pressure of the second compressor reaches the second target exhaust pressure.

[0037] In an alternative embodiment,

[0038] The control method comprises:

[0039] When the first operating frequency is the same as the second operating frequency, determining whether a first current pressure difference of the first compressor is the same as a second current pressure difference of the second compressor;

[0040] When the first current pressure difference is the same as the second current pressure difference, the opening degree of the first control valve and the opening degree of the second control valve are maintained unchanged.

[0041] In an alternative embodiment,

[0042] The control method comprises:

[0043] When the first current pressure difference is different from the second current pressure difference, the first control valve and / or the second control valve are adjusted to make the pressure difference of the first compressor the same as the pressure difference of the second compressor, and it is determined again whether the first oil level of the first compressor and the second oil level of the second compressor are both greater than or equal to the set gear.

[0044] In an alternative embodiment,

[0045] The control method comprises:

[0046] When the first oil level and / or the second oil level is lower than the set gear, the opening of the control valve on the suction branch of the compressor to be returned oil is adjusted to increase the oil level of the compressor to be returned oil until the first oil level of the first compressor and the second oil level of the second compressor are both greater than or equal to the set gear; wherein the compressor to be returned oil is the compressor of the first compressor and the second compressor whose oil level is lower than the set gear.

[0047] According to a second aspect of an embodiment of the present disclosure, there is provided a control device, which is applied to a dual compressor parallel structure, and the control device is configured to implement the control method as described in any one of the first aspects.

[0048] According to a third aspect of an embodiment of the present disclosure, a dual compressor parallel structure is provided, the dual compressor parallel structure comprising a first compressor, a second compressor, a first suction branch and a second suction branch, the outlet of the first suction branch is connected to the inlet of the first compressor, the outlet of the second suction branch is connected to the inlet of the second compressor, a first control valve is provided on the first suction branch, and a second control valve is provided on the second suction branch;

[0049] The dual compressor parallel structure also includes a control device, the first control valve and the second control valve are electrically connected to the control device respectively, and the control device is configured to implement the control method as described in any one of the first aspects.

[0050] According to a fourth aspect of an embodiment of the present disclosure, an air-conditioning device is provided, comprising the dual compressor parallel structure as described in the third aspect.

[0051] The technical solution provided by the embodiments of the present disclosure may include the following beneficial effects: In the present disclosure, the dual compressor parallel structure includes a first compressor, a second compressor, a first suction branch and a second suction branch, the outlet of the first suction branch is connected to the inlet of the first compressor, the outlet of the second suction branch is connected to the inlet of the second compressor, a first control valve is provided on the first suction branch, and a second control valve is provided on the second suction branch. During the startup process of the dual compressor parallel structure, when it is detected that one of the compressors has been started and the other compressor has not yet started, the pressure difference between the exhaust pressure and the suction pressure of the unstarted compressor is reduced by adjusting the opening of the control valve (referred to as the target control valve) corresponding to the unstarted compressor (referred to as the target compressor) to control the startup of the unstarted compressor, thereby avoiding the unstarted compressor from starting with load, so as to better ensure the smooth startup of the unstarted compressor, reduce the risk of compressor damage, and improve the reliability and stability of the entire air-conditioning equipment to which the dual compressor parallel structure belongs.

[0052] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0054] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0055] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0056] Figure 1 is a system schematic diagram of an air conditioning device according to an exemplary embodiment.

[0057] Figure 2 It is a flowchart of a control method according to an exemplary embodiment.

[0058] Figure 3 It is a schematic structural diagram of oil level detection according to an exemplary embodiment.

[0059] Figure 4is a schematic diagram of an oil level detection circuit according to an exemplary embodiment.

[0060] Reference numerals:

[0061] 11. First compressor; 12. Second compressor;

[0062] 21. First control valve; 22. Second control valve;

[0063] 31. First one-way valve; 32. Second one-way valve;

[0064] 41. Oil separator; 42. Gas-liquid separator; 43. Heating electronic expansion valve; 44. Refrigeration electronic expansion valve; 45. Plate heat exchanger; 46. Fin heat exchanger; 47. IPM module; 48. Solenoid valve; 49. Four-way valve; 50. High-pressure sensor;

[0065] 10. Outer wall of compressor; 20. Oil; 30. Printed circuit board; 40. Control device. DETAILED DESCRIPTION

[0066] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0067] The disclosure below provides many different embodiments or examples to implement different schemes of the present invention. In order to simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention. In addition, the present invention can repeat reference numbers and / or letters in different examples. This repetition is for the purpose of simplification and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed.

[0068] For ease of description, spatial relative terms may be used herein to describe the relative positional relationship or movement of one element or feature relative to another element or feature as shown in the figure, such as "inside", "outside", "inner side", "outer side", "below", "below", "above", "above", "front", "back", etc. Such spatial relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the figure. For example, if the device in the figure undergoes a position flip or a posture change or a motion state change, then these directional indications also change accordingly, for example: an element described as "below other elements or features" or "below other elements or features" will subsequently be oriented as "above other elements or features" or "above other elements or features". Therefore, the example term "below..." may include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions) and the spatial relative descriptors used herein are interpreted accordingly.

[0069] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application, and thus the drawings only show components related to the present application rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed at will, and the component layout may also be more complicated.

[0070] The following will describe the implementation methods of the present application with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. The present application can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be understood that the preferred embodiments are only for illustrating the present application, not for limiting the scope of protection of the present application.

[0071] In order to solve the technical problem in the prior art that one compressor in a dual compressor parallel structure is started first, resulting in the other compressor starting under load, the present disclosure provides a control method, a control device, a dual compressor parallel structure and an air-conditioning device.

[0072] Among them, in the present disclosure, the dual compressor parallel structure includes a first compressor, a second compressor, a first suction branch and a second suction branch, the outlet of the first suction branch is connected to the inlet of the first compressor, the outlet of the second suction branch is connected to the inlet of the second compressor, a first control valve is arranged on the first suction branch, and a second control valve is arranged on the second suction branch. During the startup process of the dual compressor parallel structure, when it is detected that one of the compressors has been started and the other compressor has not yet started, the pressure difference between the exhaust pressure and the suction pressure of the unstarted compressor is reduced by adjusting the opening of the control valve (referred to as the target control valve) corresponding to the unstarted compressor (referred to as the target compressor) to control the startup of the unstarted compressor, thereby avoiding the unstarted compressor from starting with load, so as to better ensure the smooth startup of the unstarted compressor, reduce the risk of compressor damage, and improve the reliability and stability of the entire air-conditioning equipment to which the dual compressor parallel structure belongs.

[0073] In an exemplary embodiment, a dual compressor parallel structure, a control method and a control device applied to the dual compressor parallel structure, and an air conditioning device with the dual compressor parallel structure are provided. Figure 1 and Figure 2 As shown, the dual compressor parallel structure may include a first compressor 11, a second compressor 12, a first suction branch and a second suction branch. The outlet of the first suction branch is connected to the inlet of the first compressor 11, and the outlet of the second suction branch is connected to the inlet of the second compressor 12. A first control valve 21 is provided on the first suction branch, and a second control valve 22 is provided on the second suction branch. The first control valve 21 and the second control valve 22 may be electric control valves, such as electronic expansion valves.

[0074] The dual compressor parallel structure may further include a control device, and the first control valve 21 and the second control valve 22 are electrically connected to the control device respectively. The control device may use a programmable logic controller (PLC) as a core control unit. It may integrate multiple sensor interfaces, including a suction pressure sensor interface, an exhaust pressure sensor interface, a temperature sensor interface, and a current sensor interface of the compressor, and may collect various operating parameters of the dual compressor parallel structure in real time.

[0075] The control device may be configured to, during the startup process of the dual compressor parallel structure, when it is detected that one compressor has been started and the other compressor has not been started, reduce the pressure difference between the exhaust pressure and the suction pressure of the target compressor by adjusting the opening of the target control valve to control the start of the target compressor. The target compressor is the compressor that has not been started among the first compressor 11 and the second compressor 12, and the target control valve is the control valve on the suction side of the target compressor among the first control valve 21 and the second control valve 22.

[0076] Among them, a special control algorithm program can be stored inside the control device. During the startup process of the dual-compressor parallel structure, the startup status of the compressor can be accurately judged based on the data fed back by the sensor, and control instructions can be issued in time to adjust the opening of the control valve on the suction branch to achieve control of the pressure difference between the compressor exhaust and suction pressure, ensuring the smooth startup of the unstarted compressor.

[0077] For example, during the startup process of the dual compressor parallel structure, if it is detected that the first compressor 11 has completed startup first, but the second compressor 12 has not yet started, the opening of the second control valve 22 can be adjusted to increase the suction pressure of the second compressor 12, thereby reducing the pressure difference between the exhaust pressure and the suction pressure of the second compressor 12, thereby reducing the load of the second compressor 12 or even eliminating the load of the second compressor 12 to avoid starting the second compressor 12 with load, so that the second compressor 12 can be started smoothly, which will also reduce the risk of compressor damage and improve the reliability and stability of the entire air-conditioning equipment to which the dual compressor parallel structure belongs.

[0078] For another example, during the startup of the dual-compressor parallel structure, if it is detected that the second compressor 12 has completed startup first but the first compressor 11 has not yet started, the opening of the first control valve 21 can be adjusted to increase the suction pressure of the first compressor 11, thereby reducing the pressure difference between the exhaust pressure and the suction pressure of the first compressor 11, thereby reducing the load of the first compressor 11 or even eliminating the load of the first compressor 11 to avoid starting the first compressor 11 with load, so that the first compressor 11 can be started smoothly, which will also reduce the risk of compressor damage and improve the reliability and stability of the entire air-conditioning equipment to which the dual-compressor parallel structure belongs.

[0079] The dual compressor parallel structure may include four pressure detection devices (such as pressure sensors, not shown in the figure), and the four pressure detection devices may be respectively arranged on the suction side of the first compressor 11, the exhaust side of the first compressor 11, the suction side of the second compressor 12, and the exhaust side of the second compressor 12. The pressure detection device arranged on the suction side of the first compressor 11 is recorded as the first pressure detection device, the pressure detection device arranged on the exhaust side of the first compressor 11 can be recorded as the second pressure detection device, the pressure detection device arranged on the suction side of the second compressor 12 can be recorded as the third pressure detection device, and the pressure detection device arranged on the exhaust side of the second compressor 12 can be recorded as the fourth pressure detection device.

[0080] In the process of reducing the pressure difference between the exhaust pressure and the suction pressure of the target compressor by adjusting the opening of the target control valve, the current exhaust pressure and the current suction pressure of the target compressor can be obtained first. For example, when the target compressor is the first compressor 11, the control device can obtain the current suction pressure of the first compressor 11 through the first pressure detection device, and the control device can obtain the current exhaust pressure of the first compressor 11 through the second pressure detection device.

[0081] After obtaining the current suction pressure and the current exhaust pressure, the current pressure difference of the target compressor can be determined based on the current exhaust pressure and the current suction pressure. For example, the current pressure difference can be obtained by subtracting the current suction pressure from the current exhaust pressure of the target compressor.

[0082] Among them, after obtaining the current pressure difference of the target compressor, the opening adjustment information of the target control valve can be obtained based on the current pressure difference. For example, when the target compressor is the first compressor 11, after obtaining the current pressure difference of the first compressor 11, the opening adjustment information of the first control valve 21 can be determined based on the current pressure difference.

[0083] It should be noted that when determining the opening adjustment information of the target control valve based on the current pressure difference, it may be determined based on the current pressure difference alone, or based on the current pressure difference in combination with other information, and there is no limitation on this.

[0084] In some embodiments,

[0085] The control device may be configured with first opening adjustment configuration information, which may include a one-to-one correspondence between a plurality of set pressure differences and a plurality of set opening adjustment information, and the first opening adjustment configuration information may be determined in advance according to actual experiments or simulation experiments. In this embodiment, after obtaining the current pressure difference, the set opening adjustment information corresponding to the set pressure difference that is the same as the current pressure difference in the first opening adjustment configuration information may be determined as the required opening adjustment information of the target control valve.

[0086] In other embodiments,

[0087] When determining the opening adjustment information of the target control valve based on the current pressure difference, the reference suction pressure and reference exhaust pressure of the target compressor can be obtained first. The reference suction pressure is the suction pressure of the target compressor when the started compressor is not started; the reference exhaust pressure is the exhaust pressure of the target compressor when the started compressor is not started. In other words, the reference suction pressure is the suction pressure of the unstarted compressor before it is affected by the started compressor; the reference exhaust pressure is the exhaust pressure of the unstarted compressor before it is affected by the started compressor.

[0088] In this embodiment, after obtaining the reference suction pressure and the reference exhaust pressure, the reference pressure difference of the target compressor can be determined based on the reference suction pressure and the reference exhaust pressure. The specific method can refer to the method for determining the current pressure difference, which will not be described in detail here.

[0089] After obtaining the reference pressure difference and the current pressure difference, the opening adjustment information can be determined based on the difference between the two pressure differences. The control device can be provided with second opening adjustment configuration information, and the second opening adjustment configuration information can include a one-to-one correspondence between a plurality of set differences and a plurality of set opening adjustment information. In this embodiment, after obtaining the above difference, the set opening adjustment information corresponding to the set difference that is the same as the above difference in the second opening adjustment configuration information can be determined as the required opening adjustment information of the target control valve.

[0090] It should be noted that, in addition to determining the opening adjustment information in the above manner, it may also be determined in other manners, which are not limited thereto.

[0091] After the opening adjustment information is determined, the opening of the target control valve can be adjusted based on the opening adjustment information to increase the suction pressure of the target compressor, thereby reducing the pressure difference between the exhaust pressure and the suction pressure of the target compressor.

[0092] In this embodiment, during the startup process of the dual compressor parallel structure, when it is detected that one of the compressors has been started and the other compressor has not yet started, the pressure difference between the exhaust pressure and the suction pressure of the unstarted compressor is reduced by adjusting the opening of the control valve (referred to as the target control valve) corresponding to the unstarted compressor (referred to as the target compressor), so as to control the startup of the unstarted compressor, thereby avoiding the unstarted compressor from starting under load, better ensuring the smooth startup of the unstarted compressor, reducing the risk of compressor damage, and improving the reliability and stability of the entire air-conditioning equipment to which the dual compressor parallel structure belongs.

[0093] In an exemplary embodiment, a dual compressor parallel structure, a control method and a control device applied to the dual compressor parallel structure, and an air conditioning device with the dual compressor parallel structure are provided.

[0094] Among them, reference Figure 1 and Figure 2 As shown, in the dual compressor parallel structure, during the operation of the compressor, due to frequency limiting or other reasons, the operating frequencies of the two compressors may be inconsistent. The compressor running at a high frequency inhales more air and has a higher oil return frequency, which reduces the oil return volume of the compressor running at a low frequency, easily causing certain wear and tear, thereby affecting the service life of the compressor running at a low frequency.

[0095] In this embodiment, after the first compressor 11 and the second compressor 12 in the dual compressor parallel structure are both started, and after the first compressor 11 and the second compressor 12 have both run for a set period of time, it is determined whether the first oil level of the first compressor 11 and the second oil level of the second compressor 12 are both greater than or equal to the set gear.

[0096] It should be noted that the above-mentioned set time and set gear can be set according to actual needs, and there is no limitation on their specific information. For example, the set time can be 30 minutes. The oil level of the compressor can be divided into the first gear, the second gear, the third gear and the fourth gear, and the oil levels corresponding to the above four gears gradually increase, and the set gear can be the above-mentioned first gear.

[0097] Wherein, when the first oil level and / or the second oil level is less than the set gear, it indicates that one of the first compressor 11 and the second compressor 12 has a lower oil level. In this case, the opening of the control valve on the suction branch of the compressor to be returned oil can be adjusted to increase the oil level of the compressor to be returned oil until the first oil level of the first compressor 11 and the second oil level of the second compressor 12 are both greater than or equal to the set gear. Wherein, the compressor to be returned oil is the compressor of the first compressor 11 and the second compressor 12 whose oil level is less than the set gear.

[0098] For example, when the first oil level is less than the set gear and the second oil level is greater than or equal to the set gear, it means that the oil level of the first compressor 11 is low and the first compressor 11 may have severe wear. The opening of the first control valve 21 can be adjusted to increase the pressure difference of the first compressor 11 (i.e., the pressure difference between the exhaust side and the intake side), thereby increasing the oil return frequency of the first compressor 11, and then increasing the oil level of the first compressor 11, so that the oil level of the first compressor 11 and the oil level of the second compressor 12 are both greater than or equal to the set gear.

[0099] For another example, when the second oil level is less than the set gear and the first oil level is greater than or equal to the set gear, it means that the oil level of the second compressor 12 is low and the second compressor 12 may have severe wear. The opening of the second control valve 22 can be adjusted to increase the pressure difference of the second compressor 12, thereby increasing the oil return frequency of the second compressor 12, and then increasing the oil level of the second compressor 12, so that the oil level of the first compressor 11 and the oil level of the second compressor 12 are both greater than or equal to the set gear.

[0100] For another example, when the first oil level and the second oil level are both lower than the set gear, it means that the oil levels of the first compressor 11 and the second compressor 12 are both low, and both may be severely worn. The openings of the first control valve 21 and the second control valve 22 can be adjusted to increase the pressure difference between the first compressor 11 and the second compressor 12, thereby increasing the oil return frequency of the first compressor 11 and the second compressor 12, and then increasing the oil level of the first compressor 11 and the second compressor 12, so that the oil level of the first compressor 11 and the oil level of the second compressor 12 are both greater than or equal to the set gear.

[0101] Wherein, when the first oil level and the second oil level are both greater than or equal to the set gear, it is determined whether the first operating frequency of the first compressor 11 is the same as the second operating frequency of the second compressor 12. When the first operating frequency is different from the second operating frequency, the opening of the first control valve 21 is adjusted to match the operating frequency of the first compressor 11 with the exhaust pressure of the first compressor 11, so that the oil return condition of the first compressor 11 matches the operating frequency to avoid wear of the first compressor 11. The opening of the second control valve 22 is adjusted to match the operating frequency of the second compressor 12 with the exhaust pressure of the second compressor 12, so that the oil return condition of the second compressor 12 matches the operating frequency to avoid wear of the second compressor 12.

[0102] In the process of adjusting the opening of the first control valve 21 so that the operating frequency of the first compressor 11 matches the exhaust pressure of the first compressor 11, the frequency-pressure configuration information of the first compressor 11 can be firstly obtained. The frequency-pressure configuration information of the first compressor 11 represents the corresponding relationship between the mutually matching operating frequency and exhaust pressure of the first compressor 11. Then, based on the first operating frequency and the frequency-pressure configuration information of the first compressor 11, the first target exhaust pressure of the first compressor 11 is determined. Then, the opening of the first control valve 21 is adjusted so that the exhaust pressure of the first compressor 11 reaches the first target exhaust pressure, thereby achieving the matching of the operating frequency of the first compressor 11 and the exhaust pressure of the first compressor 11.

[0103] It should be noted that the frequency-pressure configuration information of the first compressor 11 can also be recorded as a frequency-pressure limitation diagram, which is related to the specific performance of the first compressor 11 and can be determined through actual experiments or simulation experiments or through other methods, without limitation.

[0104] In the process of adjusting the opening of the second control valve 22 so that the operating frequency of the second compressor 12 matches the exhaust pressure of the second compressor 12, the frequency-pressure configuration information of the second compressor 12 can be first obtained. The frequency-pressure configuration information of the second compressor 12 represents the corresponding relationship between the mutually matching operating frequency and exhaust pressure of the second compressor 12. Then, based on the second operating frequency and the frequency-pressure configuration information of the second compressor 12, the second target exhaust pressure of the second compressor 12 is determined. Then, the opening of the second control valve 22 is adjusted so that the exhaust pressure of the second compressor 12 reaches the second target exhaust pressure, thereby achieving the matching of the operating frequency of the second compressor 12 and the exhaust pressure of the second compressor 12.

[0105] It should be noted that the frequency-pressure configuration information of the second compressor 12 can also be recorded as a frequency-pressure limitation diagram, which is related to the specific performance of the second compressor 12 and can be determined through actual experiments or simulation experiments or by other means, without limitation.

[0106] Among them, when the first oil level and the second oil level are both greater than or equal to the set gear, and when the first operating frequency of the first compressor 11 is the same as the second operating frequency of the second compressor 12, it can be determined whether the first current pressure difference of the first compressor 11 is the same as the second current pressure difference of the second compressor 12.

[0107] Among them, when the first current pressure difference is the same as the second current pressure difference, it means that the oil return conditions of the first compressor 11 and the second compressor 12 are equivalent (that is, the same within the allowable error range), and the opening of the first control valve 21 and the opening of the second control valve 22 can be maintained unchanged.

[0108] Among them, when the first oil level and the second oil level are both greater than or equal to the set gear, and when the first operating frequency of the first compressor 11 is the same as the second operating frequency of the second compressor 12, and when the first current pressure difference is different from the second current pressure difference, it means that there is a certain difference in the oil return conditions of the first compressor 11 and the second compressor 12, which may cause a large difference in the oil level of the first compressor 11 and the second compressor 12, thereby causing a large difference in the degree of wear of the first compressor 11 and the second compressor 12. In this case, the first control valve 21 and / or the second control valve 22 can be adjusted to make the pressure difference of the first compressor 11 the same as the pressure difference of the second compressor 12. After the pressure difference between the two is the same, it is judged again whether the first oil level of the first compressor 11 and the second oil level of the second compressor 12 are both greater than or equal to the set gear, and then subsequent operations are performed based on the judgment result to better avoid the wear of the first compressor 11 and the second compressor 12.

[0109] In this embodiment, during the operation of the first compressor 11 and the second compressor 12, through real-time monitoring of the compressor oil level and optimization of the oil return frequency based on the control valve opening adjustment, as well as precise matching of the operating frequency and the exhaust pressure, the uneven oil return and wear problems caused by the frequency difference are effectively solved, thereby improving the life and reliability of the compressor.

[0110] In an exemplary embodiment, a dual compressor parallel structure, a control method and a control device applied to the dual compressor parallel structure, and an air conditioning device with the dual compressor parallel structure are provided.

[0111] Among them, reference Figure 1 and Figure 2 As shown, in addition to the above-mentioned dual compressor parallel structure, the air conditioning equipment also includes an oil separator 41, a vapor-liquid separator 42, a fin heat exchanger 46, a heating electronic expansion valve 43, a cooling electronic expansion valve 44, a plate heat exchanger 45, an IPM module 47, a four-way valve 49, a solenoid valve 48 and other devices. IPM (Intelligent Power Module) module, that is, intelligent power module, is a highly integrated power semiconductor device.

[0112] Among them, the dual compressor parallel structure may include an intake pipeline, an exhaust pipeline, and a first compressor 11 and a second compressor 12. The intake pipeline may include a first intake branch and a second intake branch. The exhaust pipeline may include a first exhaust branch and a second exhaust branch. A first control valve 21 is provided on the first intake branch, a second control valve 22 is provided on the second intake branch, a first check valve 31 is provided on the first exhaust branch, and a second check valve 32 is provided on the second exhaust branch. A first pressure detection device may be provided on the upstream side of the first control valve 21 on the first intake branch, a second pressure detection device may be provided on the downstream side of the first check valve 31 on the first exhaust branch, a third pressure detection device may be provided on the upstream side of the second control valve 22 on the second intake branch, and a fourth pressure detection device may be provided on the downstream side of the second check valve 32 on the second exhaust branch. In addition, a high-pressure sensor 50 may be provided on the exhaust pipeline to detect the exhaust pressure on the exhaust pipeline, that is, the overall exhaust pressure of the dual compressor parallel structure.

[0113] The connection relationship between the components in the air conditioning equipment can be referred to Figure 1In the air-conditioning device, when the whole machine is turned on, the status of the two compressors is detected in real time. When one compressor starts successfully and the other has not started successfully, a pressure difference is formed between the suction pressure and the exhaust pressure of the dual compressor parallel structure. At this time, the control valve (referred to as the target control valve) corresponding to the compressor that has not been started (referred to as the target compressor) can be adjusted to increase the pressure on the suction side of the target compressor and reduce the pressure difference of the target compressor, thereby preventing the target compressor from starting under a large pressure difference (i.e., load) to improve the reliability of the starting performance.

[0114] During the operation of the two compressors after they are started, the operating frequencies of the two compressors may be inconsistent due to frequency limiting. The compressor running at a high frequency inhales more air and has a higher oil return frequency, which causes certain wear to the compressor running at a low frequency, thereby affecting the service life of the compressor.

[0115] In this embodiment, during the operation of both compressors after they are started, after both the first compressor 11 and the second compressor 12 have been running for 30 minutes, it is determined whether the first oil level of the first compressor 11 and the second oil level of the second compressor 12 are both greater than or equal to the first gear. The oil levels of both compressors can be divided into the first gear, the second gear, the third gear and the fourth gear, and the oil levels corresponding to the above four gears gradually increase.

[0116] Wherein, when the first oil level and / or the second oil level is less than the set gear, it indicates that one of the first compressor 11 and the second compressor 12 has a lower oil level. In this case, the opening of the control valve on the suction branch of the compressor to be returned oil can be adjusted to increase the oil level of the compressor to be returned oil until the first oil level of the first compressor 11 and the second oil level of the second compressor 12 are both greater than or equal to the set gear. Wherein, the compressor to be returned oil is the compressor of the first compressor 11 and the second compressor 12 whose oil level is less than the set gear.

[0117] Wherein, when the first oil level and the second oil level are both greater than or equal to the set gear, it is determined whether the first operating frequency of the first compressor 11 is the same as the second operating frequency of the second compressor 12. When the first operating frequency is different from the second operating frequency, the opening of the first control valve 21 is adjusted to match the operating frequency of the first compressor 11 with the exhaust pressure of the first compressor 11, so that the oil return condition of the first compressor 11 matches the operating frequency to avoid wear of the first compressor 11. The opening of the second control valve 22 is adjusted to match the operating frequency of the second compressor 12 with the exhaust pressure of the second compressor 12, so that the oil return condition of the second compressor 12 matches the operating frequency to avoid wear of the second compressor 12.

[0118] Among them, in the process of adjusting the opening of the first control valve 21 so that the operating frequency of the first compressor 11 matches the exhaust pressure of the first compressor 11, the frequency-pressure configuration information of the first compressor 11 can be obtained first. The frequency-pressure configuration information of the first compressor 11 represents the corresponding relationship between the mutually matching operating frequency and exhaust pressure of the first compressor 11. Then, based on the first operating frequency and the frequency-pressure configuration information of the first compressor 11, the first target exhaust pressure of the first compressor 11 is determined. Then, the opening of the first control valve 21 is adjusted so that the exhaust pressure of the first compressor 11 reaches the first target exhaust pressure, thereby achieving the matching of the operating frequency of the first compressor 11 and the exhaust pressure of the first compressor 11. For example, when the compressor operates at 30-44Hz and the exhaust pressure is in the range of 1.65Mpa-3.6Mpa, it is considered that the two are matched.

[0119] In the process of adjusting the opening of the second control valve 22 so that the operating frequency of the second compressor 12 matches the exhaust pressure of the second compressor 12, the frequency-pressure configuration information of the second compressor 12 can be first obtained. The frequency-pressure configuration information of the second compressor 12 represents the corresponding relationship between the mutually matching operating frequency and exhaust pressure of the second compressor 12. Then, based on the second operating frequency and the frequency-pressure configuration information of the second compressor 12, the second target exhaust pressure of the second compressor 12 is determined. Then, the opening of the second control valve 22 is adjusted so that the exhaust pressure of the second compressor 12 reaches the second target exhaust pressure, thereby achieving the matching of the operating frequency of the second compressor 12 and the exhaust pressure of the second compressor 12.

[0120] Among them, when the first oil level and the second oil level are both greater than or equal to the set gear, and when the first operating frequency of the first compressor 11 is the same as the second operating frequency of the second compressor 12, it can be determined whether the first current pressure difference of the first compressor 11 is the same as the second current pressure difference of the second compressor 12.

[0121] Among them, when the first current pressure difference is the same as the second current pressure difference, it means that the oil return conditions of the first compressor 11 and the second compressor 12 are equivalent (that is, the same within the allowable error range), and the opening of the first control valve 21 and the opening of the second control valve 22 can be maintained unchanged.

[0122] Among them, when the first oil level and the second oil level are both greater than or equal to the set gear, and when the first operating frequency of the first compressor 11 is the same as the second operating frequency of the second compressor 12, and when the first current pressure difference is different from the second current pressure difference, it means that there is a certain difference in the oil return conditions of the first compressor 11 and the second compressor 12, which may cause a large difference in the oil level of the first compressor 11 and the second compressor 12, thereby causing a large difference in the degree of wear of the first compressor 11 and the second compressor 12. In this case, the first control valve 21 and / or the second control valve 22 can be adjusted to make the pressure difference of the first compressor 11 the same as the pressure difference of the second compressor 12. After the pressure difference between the two is the same, it is judged again whether the first oil level of the first compressor 11 and the second oil level of the second compressor 12 are both greater than or equal to the set gear, and then subsequent operations are performed based on the judgment result to better avoid the wear of the first compressor 11 and the second compressor 12.

[0123] Among them, regarding the design of oil level detection of the compressor, this embodiment mainly uses a new chip as a sensor to detect the oil level position in the compressor, and controls the first control valve 21 and / or the second control valve 22 according to the oil level position to prevent compressor wear when the oil amount is low.

[0124] Among them, reference Figure 3 As shown, Figure 3 The sensor includes the compressor outer wall 10, the oil in the compressor 20, the sensor printed circuit board 30 (PCB, which is a key component of the sensor) and the control device 40. The sensor is mainly used to detect the position of the oil in the compressor, which is reflected in the output voltage. The oil position can be divided into four gears (first gear G1, second gear G2, third gear G3, fourth gear G4). When the oil level is in the first gear G1, it is considered that the oil is less, and the pressure difference needs to be adjusted to improve the oil return of the compressor to avoid wear.

[0125] The schematic diagram of the oil level detection circuit is as follows Figure 4As shown, it is a circuit schematic diagram of the oil level detection of the first compressor 11. The oil level detection circuit may include a first control valve 21, a transistor Q, a first resistor R1 and a second resistor R2. The specific resistance values ​​of the first resistor R1 and the second resistor R2 can be set according to actual needs, and there is no limitation on this. Among them, the output voltage Vo of the oil level corresponding to the second gear and the gears above is the reference voltage Vref. When the input voltage Vin is greater than the reference voltage Vref, the output voltage Vo is low, and the transistor Q is not turned on. In this case, the opening of the first control valve 21 can be adjusted; when the oil level is equal to or less than the first gear, the input voltage Vin is less than the reference voltage Vref, the output voltage Vo is high, and the transistor Q is turned on. In this case, the pressure difference of the first compressor 11 can be controlled by adjusting the opening of the first control valve 21, thereby adjusting the oil return of the first compressor 11. The circuit principle of the oil level detection of the second compressor 12 can refer to the first compressor 11, and no further description is given.

[0126] In this embodiment, during the startup phase of the dual compressor parallel structure, if it is detected that the two compressors are not started at the same time, the control valve of the failed compressor is adjusted to increase the pressure on the suction side of the compressor so that the pressure difference is maintained at a value suitable for the compressor startup. Half an hour after the compressor that starts later is started, the opening of the corresponding control valve can be adjusted based on parameters such as the oil level, pressure difference and operating frequency of the two compressors, so that the operating frequency and pressure difference of the two compressors are the same, or the operating frequency of the two compressors is adapted to the corresponding pressure difference, so as to ensure that the oil return conditions of the two compressors are equivalent, ensure that the oil levels of the two compressors meet the requirements, and avoid wear of the compressors.

[0127] The professionals should also be further aware that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented with electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in terms of function in the above description. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0128] It should be noted that the phrases "one implementation", "an embodiment", "an exemplary embodiment", "some embodiments", etc. mentioned in the specification indicate that the described embodiments may include certain features, structures or characteristics, but not every embodiment may include the certain features, structures or characteristics. In addition, such phrases do not necessarily refer to the same embodiment. In addition, when describing certain features, structures or characteristics in conjunction with an embodiment, it is within the knowledge of those skilled in the art to implement such features, structures or characteristics in conjunction with other embodiments, whether explicitly or not explicitly described.

[0129] It should be noted that, in this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of more limiting values, the elements defined by the sentence "comprise a..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0130] The above embodiments are only preferred embodiments for fully illustrating the present application, and the protection scope of the present application is not limited thereto. Any equivalent substitution or change made by a person skilled in the art based on the present application is within the protection scope of the present application.

Claims

1. A control method, characterized in that: The control method is applied to a dual compressor parallel structure, the dual compressor parallel structure includes a first compressor, a second compressor, a first suction branch and a second suction branch, the outlet of the first suction branch is connected to the inlet of the first compressor, the outlet of the second suction branch is connected to the inlet of the second compressor, a first control valve is provided on the first suction branch, and a second control valve is provided on the second suction branch; The control method comprises: During the startup process of the dual compressor parallel structure, when it is detected that one of the compressors has been started and the other compressor has not been started, the pressure difference between the exhaust pressure and the suction pressure of the target compressor is reduced by adjusting the opening of the target control valve to control the start of the target compressor; The target compressor is a compressor that is not started between the first compressor and the second compressor, and the target control valve is a control valve on the suction side of the target compressor between the first control valve and the second control valve.

2. The control method according to claim 1, characterized in that: The reducing the pressure difference between the exhaust pressure and the suction pressure of the target compressor by adjusting the opening of the target control valve comprises: Acquire the current exhaust pressure and the current suction pressure of the target compressor; determining a current pressure difference of the target compressor based on the current exhaust pressure and the current suction pressure; Based on the current pressure difference, determining the opening adjustment information of the target control valve; The opening degree of the target control valve is adjusted based on the opening degree adjustment information to reduce the pressure difference between the discharge pressure and the suction pressure of the target compressor.

3. The control method according to claim 2, characterized in that: The step of determining the opening adjustment information of the target control valve based on the current pressure difference includes: Obtaining a reference suction pressure and a reference exhaust pressure of the target compressor; wherein the reference suction pressure is the suction pressure of the target compressor when the started compressor is not started; the reference exhaust pressure is the exhaust pressure of the target compressor when the started compressor is not started; determining a reference pressure difference of the target compressor based on the reference suction pressure and the reference discharge pressure; The opening adjustment information is determined based on the current pressure difference and the reference pressure difference.

4. The control method according to any one of claims 1 to 3, characterized in that: The control method comprises: After the first compressor and the second compressor have both been running for a set time, determining whether a first oil level of the first compressor and a second oil level of the second compressor are both greater than or equal to a set gear; When the first oil level and the second oil level are both greater than or equal to a set gear, determining whether a first operating frequency of the first compressor and a second operating frequency of the second compressor are the same; When the first operating frequency is different from the second operating frequency, the opening of the first control valve is adjusted to match the operating frequency of the first compressor with the exhaust pressure of the first compressor, and the opening of the second control valve is adjusted to match the operating frequency of the second compressor with the exhaust pressure of the second compressor.

5. The control method according to claim 4, characterized in that: The step of adjusting the opening of the first control valve so that the operating frequency of the first compressor matches the exhaust pressure of the first compressor includes: Acquire frequency-pressure configuration information of the first compressor; wherein the frequency-pressure configuration information of the first compressor represents a corresponding relationship between mutually matching operating frequencies and exhaust pressures of the first compressor; determining a first target exhaust pressure of the first compressor based on the first operating frequency and the frequency-pressure configuration information of the first compressor; The opening degree of the first control valve is adjusted so that the exhaust pressure of the first compressor reaches the first target exhaust pressure.

6. The control method according to claim 4, characterized in that: The step of adjusting the opening of the second control valve so that the operating frequency of the second compressor matches the exhaust pressure of the second compressor includes: Acquire frequency-pressure configuration information of the second compressor; wherein the frequency-pressure configuration information of the second compressor represents the corresponding relationship between the mutually matching operating frequency and exhaust pressure of the second compressor; determining a second target exhaust pressure of the second compressor based on the second operating frequency and the frequency-pressure configuration information of the second compressor; The opening degree of the second control valve is adjusted so that the exhaust pressure of the second compressor reaches the second target exhaust pressure.

7. The control method according to claim 4, characterized in that: The control method comprises: When the first operating frequency is the same as the second operating frequency, determining whether a first current pressure difference of the first compressor is the same as a second current pressure difference of the second compressor; When the first current pressure difference is the same as the second current pressure difference, the opening degree of the first control valve and the opening degree of the second control valve are maintained unchanged.

8. The control method according to claim 7, characterized in that: The control method comprises: When the first current pressure difference is different from the second current pressure difference, the first control valve and / or the second control valve are adjusted to make the pressure difference of the first compressor the same as the pressure difference of the second compressor, and it is determined again whether the first oil level of the first compressor and the second oil level of the second compressor are both greater than or equal to the set gear.

9. The control method according to claim 4, characterized in that: The control method comprises: When the first oil level and / or the second oil level is lower than the set gear, the opening of the control valve on the suction branch of the compressor to be returned oil is adjusted to increase the oil level of the compressor to be returned oil until the first oil level of the first compressor and the second oil level of the second compressor are both greater than or equal to the set gear; wherein the compressor to be returned oil is the compressor of the first compressor and the second compressor whose oil level is lower than the set gear.

10. A control device, characterized in that: The control device is applied to a dual compressor parallel structure, and the control device is configured to implement the control method according to any one of claims 1-9.

11. A dual compressor parallel structure, characterized in that: The dual compressor parallel structure comprises a first compressor, a second compressor, a first suction branch and a second suction branch, the outlet of the first suction branch is connected to the inlet of the first compressor, the outlet of the second suction branch is connected to the inlet of the second compressor, the first suction branch is provided with a first control valve, and the second suction branch is provided with a second control valve; The dual compressor parallel structure also includes a control device, the first control valve and the second control valve are electrically connected to the control device respectively, and the control device is configured to implement the control method according to any one of claims 1-9.

12. An air conditioning device, characterized in that: The air conditioning equipment includes the dual compressor parallel structure as claimed in claim 11.

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