Control method and system for two-stage heat source type absorption heat pump

Abstract

The embodiment of the specification provides a control method and system of a double-stage heat source type absorption heat pump, wherein the method comprises: calculating a current incremental PID output value through a PID controller; determining whether current heat supply of the absorption heat pump is sufficient according to the current calculated incremental PID output value, if not, determining a current control mode, if it is a low-pressure control mode, determining whether the double-stage heat source needs to supply heat according to the current calculated incremental PID output value, if yes, controlling the maximum opening of the first-stage heat source and determining and controlling the adjustment opening of the second-stage heat source steam regulating valve, if it is a high-pressure control mode, keeping the maximum opening of the first-stage heat source and determining and controlling the increased adjustment opening of the second-stage heat source steam regulating valve. The application solves the problem that heat supply is prone to heat source shortage by controlling the double-stage heat source to participate in heat supply adjustment at the same time, and reasonably utilizes each heat supply heat source to maximize the heat supply of each heat source.

Description

Technical Field

[0001] This invention relates to the field of mechanical control technology, and in particular to a control method and system for a dual-stage heat source absorption heat pump. Background Technology

[0002] In the production processes of industries such as power, metallurgy, chemical, textile, oil extraction, and pharmaceuticals, a large amount of waste heat is often generated. If not utilized, this not only wastes energy but may also pollute the environment. Among numerous energy-saving technologies, lithium bromide absorption heat pump waste heat recovery technology stands out for its high energy efficiency and significant economic benefits. Furthermore, lithium bromide absorption heat pumps use lithium bromide solution as the working fluid, which does not pollute the environment and does not damage the atmosphere. Its high efficiency and energy saving characteristics make it widely used in waste heat recovery and utilization across various fields.

[0003] The first type of absorption heat pump (usually abbreviated as AHP) uses steam, fuel, waste hot water or waste steam as the driving heat source to raise the heat of the low temperature heat source to medium and high temperature, thereby improving energy quality and utilization efficiency.

[0004] Currently, in the field of waste heat recovery heating in thermal power plants and heat source plants, in order to solve the problem of insufficient heat source that is easy to occur when heating from a single heat source, it is necessary to set up and control any one of the two or more heat sources to participate in the heating control. However, this method cannot make optimal use of the heating from each heat source.

[0005] In view of this, there is an urgent need to provide a more reasonable and efficient control method for achieving dual-stage heat source absorption heat pump heating. Summary of the Invention

[0006] This specification provides one or more embodiments of a dual-stage heat source type-one absorption heat pump control method, including:

[0007] The current incremental PID output value is calculated using the PID controller.

[0008] Based on the currently calculated incremental PID output value, determine whether the current type-one absorption heat pump provides sufficient heat. If insufficient, determine the current control mode. If it is a low-pressure control mode, determine whether a second-stage heat source is needed for heating based on the currently calculated incremental PID output value. If so, control the maximum opening of the first-stage heat source while determining and controlling the adjustment opening of the steam regulating valve of the second-stage heat source. If it is a high-pressure control mode, maintain the maximum opening of the first-stage heat source while determining and controlling the increase in the adjustment opening of the steam regulating valve of the second-stage heat source.

[0009] This specification provides one or more embodiments of a dual-stage heat source type-one absorption heat pump control system, including...

[0010] Real-time calculation module: Calculates the current incremental PID output value through the PID controller;

[0011] Analysis and control module: Based on the incremental PID output value calculated by the real-time calculation module, determine whether the current heating supply of the first-stage absorption heat pump is sufficient. If insufficient, determine the current control mode. If it is a low-pressure control mode, determine whether a second-stage heat source is needed for heating based on the current incremental PID output value. If so, control the maximum opening of the first-stage heat source while determining and controlling the adjustment opening of the steam regulating valve of the second-stage heat source. If it is a high-pressure control mode, maintain the maximum opening of the first-stage heat source while determining and controlling the increase in the adjustment opening of the steam regulating valve of the second-stage heat source.

[0012] This invention controls two heat sources to participate in heating regulation simultaneously. When the heat supply from one heat source is insufficient, the second heat source is activated to supplement the heat supply while maintaining the maximum heat supply from the first heat source. This solves the problem of insufficient heat source in heating and makes reasonable use of each heat source to maximize the heat supply from each heat source. Attached Figure Description

[0013] To more clearly illustrate the technical solutions in one or more embodiments of this specification or in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0014] Figure 1 A flowchart illustrating a dual-stage heat source type-1 absorption heat pump control method provided for one or more embodiments of this specification;

[0015] Figure 2 A simplified schematic diagram of a type of absorption heat pump with a two-stage heat source provided for one or more embodiments of this specification;

[0016] Figure 3 A schematic diagram of a dual-stage heat source type-1 absorption heat pump control mode provided for one or more embodiments of this specification;

[0017] Figure 4 This is a schematic diagram of the framework of a dual-stage heat source type-1 absorption heat pump control system provided for one or more embodiments of this specification. Detailed Implementation

[0018] To enable those skilled in the art to better understand the technical solutions in one or more embodiments of this specification, the technical solutions in one or more embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this specification, and not all of the embodiments. Based on one or more embodiments of this specification, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this document.

[0019] The present invention will now be described in detail with reference to specific embodiments and accompanying drawings.

[0020] Method implementation examples.

[0021] According to embodiments of the present invention, a control method for a dual-stage heat source absorption heat pump is provided, such as... Figure 1 The diagram shown is a flowchart of the dual-stage heat source type-1 absorption heat pump control method provided in this embodiment. The dual-stage heat source type-1 absorption heat pump control method according to this embodiment includes:

[0022] S1. Calculate the current incremental PID output value using the PID controller;

[0023] S2. Determine whether the current type of absorption heat pump heating is sufficient based on the currently calculated incremental PID output value. If sufficient, proceed to step S1; if insufficient, determine the current control mode. If it is a low-pressure control mode, proceed to step S3; if it is a high-pressure control mode, proceed to step S4.

[0024] S3. Determine whether a second-stage heat source is needed for heating based on the currently calculated incremental PID output value. If so, control the maximum opening of the first-stage heat source while determining and controlling the adjustment opening of the steam regulating valve of the second-stage heat source, and then proceed to step S1.

[0025] S4. While maintaining the maximum opening of the first heat source, determine and control the increase of the regulating opening of the steam regulating valve of the second heat source, and then proceed to step S1.

[0026] This embodiment controls two heat sources to participate in heating regulation simultaneously. When the heat supply from one heat source is insufficient, the second heat source is activated to supplement the heat supply while maintaining the maximum heat supply from the first heat source. This solves the problem of insufficient heat source in heating and makes reasonable use of each heat source to maximize the heat supply from each heat source.

[0027] In some embodiments, to better understand the control method of a type of absorption heat pump with a two-stage heat source, refer to Figure 2The schematic diagram illustrates a simplified type of absorption heat pump with two heat sources. The first and second heat sources are connected in series to provide external heat. This diagram is intended to better understand the control method of this type of absorption heat pump based on two heat sources, but it is not limited to this method and is only applicable to... Figure 2 The diagram shows a type of absorption heat pump with a dual-stage heat source; among which,

[0028] Y1 is a low-pressure steam valve and Y2 is a high-pressure steam valve. They are the driving heat source for a type of absorption heat pump unit. By adjusting the opening of valves Y1 and Y2, the final control target of the heat pump unit, the outlet temperature of the heating network water (and the supply water temperature), can be controlled and regulated.

[0029] A1: First generator;

[0030] A2: Second generator;

[0031] B1: Condenser;

[0032] C: Absorber;

[0033] D: Evaporator;

[0034] Low-pressure driving steam enters the first generator A1 through the low-pressure steam regulating valve Y1 to increase the concentration of the lithium bromide solution injected from the absorber. The lithium bromide solution then flows back to the absorber to heat the heating network water. The heating network water is then heated a second time by the absorber and condenser before leaving the system for heating. When the outlet temperature of the heating network water controlled by the system is low, the second-stage high-pressure steam regulating valve Y2 is activated. High-pressure steam enters the second generator A2 through the high-pressure steam regulating valve Y2 to further increase the concentration of the lithium bromide solution flowing from the first generator A1 to the second generator A2, thereby increasing the temperature of the solution returning to the absorber. This dual-stage heat source control method is required depending on the different heating requirements.

[0035] In some embodiments, the incremental PID output value is determined by PID calculations of five control sources, including the following five control sources, each with a preset target value based on heating demand. The five control sources are:

[0036] PID(YK1): Temperature control source for the outlet water temperature of the condenser B1 heating network;

[0037] PID(YK2): The outlet temperature control source for the second generator A2;

[0038] PID(YK3): The concentration control source for the second generator A2 solution;

[0039] PID (YK4): Evaporation temperature control source;

[0040] PID (YK5): Cold water outlet temperature control source;

[0041] refer to Figure 3 As shown, during the heating process, in the low-pressure control mode, the size of the first-stage low-pressure steam valve Y1 is adjusted by PID control to enable the first-stage heat source to complete the external supply and meet the heating requirements. At this time, the valves of the second-stage heat source are closed and do not participate in the heating. In the high-pressure control mode, if the first-stage heat source is insufficient to supply heat, under the condition that the opening of the first-stage low-pressure steam valve Y1 is at its maximum, the size of the second-stage high-pressure steam valve Y2 is adjusted by PID control to enable the second-stage heat source to participate and complete the external supply and meet the heating requirements simultaneously with the first-stage heat source.

[0042] In some embodiments, adjusting the opening degrees of valves Y1 and Y2 based on the incremental PID output value may include the following control scenarios:

[0043] 1) When the real-time calculated values ​​of the condenser B1 heat network water outlet temperature, the second generator A2 outlet temperature, and the second generator A2 solution concentration are all less than the target values, it indicates that the current dual-stage heat source type-I absorption heat pump is insufficient to supply heat to the outside. Then, according to the real-time incremental PID output value, the opening degree of the first-stage low-pressure steam valve Y1 or the second-stage high-pressure steam valve Y2 is sequentially increased.

[0044] When the real-time calculated values ​​of the condenser B1 heat network water outlet temperature, the second generator A2 outlet temperature, or the second generator A2 solution concentration are greater than the target values, it indicates that the current dual-stage heat source type-I absorption heat pump is providing sufficient external heat. Then, based on the real-time incremental PID output value, the opening degree of the second-stage high-pressure steam valve Y2 or the first-stage low-pressure steam valve Y1 is sequentially reduced.

[0045] 2) When the real-time calculated values ​​of the evaporation temperature and the cold water outlet temperature are both greater than the target values, it indicates that the current dual-stage heat source type-I absorption heat pump is insufficient to supply heat to the outside. Then, according to the real-time incremental PID output value, the opening degree of the first-stage low-pressure steam valve Y1 or the second-stage high-pressure steam valve Y2 is sequentially increased.

[0046] When the real-time calculated value of the evaporation temperature or the cold water outlet temperature is less than the target value, it indicates that the current dual-stage heat source type-I absorption heat pump is providing sufficient external heat. Then, based on the real-time incremental PID output value, the opening degree of the second-stage high-pressure steam valve Y2 or the first-stage low-pressure steam valve Y1 is sequentially reduced.

[0047] according to Figure 2 and Figure 3 In this embodiment of the dual-stage heat source type-I absorption heat pump control method, the specific switching between low-pressure control mode and high-pressure control mode includes the following situations and calculations:

[0048] 1) When the heat pump unit is just started, the device is in the cold state mode. To ensure the stability of the unit, it is in the low-pressure control mode at this time. The first-stage heat source provides heat, and only the first-stage low-pressure steam valve Y1 participates in the PID regulation. The second-stage high-pressure steam regulating valve Y2 is always in the closed state. The opening output calculation of the first-stage low-pressure steam regulating valve is as follows:

[0049] Y1 开 = Y1C + Y1K;

[0050] Y1K = MIN(PID(YK1), PID(YK2), PID(YK3), PID(YK4), PID(YK5));

[0051] Y1max >= Y1 开 >= Y1min;

[0052] Y1Dmax >= Y1K >= Y1Dmin;

[0053] In the formula, Y1 开 is the opening output of the first-stage low-pressure steam regulating valve Y1, Y1C is the opening output of the current first-stage steam regulating valve; Y1K is the incremental PID output value (the minimum value of 5 control sources); Y1max is the maximum opening of the first-stage low-pressure steam regulating valve; Y1min is the minimum opening of the first-stage low-pressure steam regulating valve; Y1Dmax is the maximum value of the incremental PID action of the first-stage low-pressure steam regulating valve; Y1Dmin is the minimum value of the incremental PID action of the first-stage low-pressure steam regulating valve;

[0054] 2) If none of the 5 control sources reach the target value and the opening of the first-stage low-pressure steam valve Y1 reaches the maximum opening, it can be judged that the first-stage low-pressure steam heat source is insufficient. Then the high-pressure control mode is started. The judgment conditions for opening the second-stage high-pressure steam valve Y2 are as follows:

[0055] That is, when Y1 开 = Y1max, and PV1 in PID(YK1) < SP1 - DT1, PV2 in PID(YK2) < SP2 - DT2, PV3 in PID(YK3) < SP3 - DT3, PV4 in PID(YK4) > SP4 + DT4, PV5 in PID(YK5) > SP5 + DT5, it means that the current heat source is insufficient. Then enter the high-pressure control mode. The first-stage low-pressure steam regulating valve Y1 maintains the maximum opening and no longer participates in the PID regulation. The second-stage high-pressure steam regulating valve Y2 participates in the PID regulation; By participating in heat supply through the second-stage low-pressure steam regulation, the problem of insufficient heat source caused by only using the first-stage heat source for external heat supply can be stably solved.

[0056] Among them:

[0057] PV1-PV5 correspond to the current condenser B1 hot water outlet temperature control source feedback value, the second generator A2 outlet temperature control source feedback value, the second generator A2 solution concentration control source feedback value, the evaporation temperature control source feedback value, and the cold water outlet temperature control source feedback value, respectively.

[0058] DT1-DT5 correspond to the deviation values ​​of the target values ​​of the current condenser B1 hot water outlet temperature control source, the second generator A2 outlet temperature control source, the second generator A2 solution concentration control source, the evaporation temperature control source, and the cold water outlet temperature control source, respectively.

[0059] SP1-SP5 correspond to the preset target values ​​of the current condenser B1 hot water outlet temperature control source, the preset target value of the second generator A2 outlet temperature control source, the preset target value of the second generator A2 solution concentration control source, the preset target value of the evaporation temperature control source, and the preset target value of the cold water outlet temperature control source, respectively.

[0060] Y2 开 =Y2C + Y2K;

[0061] Y2K=MIN(PID(YK1), PID(YK2), PID(YK3), PID(YK4), PID(YK5));

[0062] Y2max>=Y2 开 >=Y2min;

[0063] Y2Dmax >= Y2K >= Y2Dmin;

[0064] In the formula, Y2 开 Y2C is the current opening output of the two-stage high-pressure steam regulating valve; Y2K is the incremental PID output value (minimum value of 5 control sources); Y2max is the maximum opening value of the two-stage high-pressure steam regulating valve; Y2min is the minimum opening value of the two-stage high-pressure steam regulating valve; Y2Dmax is the maximum incremental PID action value of the two-stage high-pressure steam regulating valve; Y2Dmin is the minimum incremental PID action value of the two-stage high-pressure steam regulating valve.

[0065] 3) Under high-voltage control mode, when Y2 开= Y2min, and when one of the following control conditions is met in PID(YK1) where PV1 > SP1 + DT1, in PID(YK2) where PV2 > SP2 + DT2, in PID(YK3) where PV3 > SP3 + DT3, in PID(YK4) where PV4 < SP4 - DT4, or in PID(YK5) where PV5 < SP5 - DT5, it indicates that the current heat source is sufficient. The second-stage high-pressure steam regulating valve Y2 closes to the minimum opening and no longer participates in PID regulation, entering the low-pressure control mode, and the first-stage low-pressure steam valve resumes PID regulation.

[0066] In some embodiments, the control method of this embodiment may specifically include the following steps:

[0067] S101. Determine whether the heat supply of the heat pump unit is sufficient according to the current PID control calculation result. If it is sufficient, continue to execute step S101; if it is not sufficient, go to step S102;

[0068] S102. Determine the current control mode. If it is the low-pressure control mode, go to step S103; if it is the high-pressure control mode, go to step S104;

[0069] S103. Determine whether the opening of the first-stage heat source steam regulating valve Y1 is the maximum. If it is not, determine and control the increased regulating opening of the first-stage heat source steam regulating valve Y1 according to the current PID control calculation result. If it is the maximum, start the high-pressure control mode. While the opening of the first-stage heat source steam regulating valve Y1 is the maximum, determine and control the regulating opening of the second-stage heat source steam regulating valve Y2 according to the current PID control calculation result, and go to step S101;

[0070] S104. Determine whether the opening of the current second-stage heat source steam regulating valve Y2 is the minimum. If it is not, determine and control the increased regulating opening of the second-stage heat source steam regulating valve Y2 according to the current PID control calculation result.

[0071] System embodiment.

[0072] According to an embodiment of the present invention, a dual-stage heat source first-class absorption heat pump control system is provided. As Figure 4 shown, it is a schematic structural diagram of the dual-stage heat source first-class absorption heat pump control system provided by this embodiment. The dual-stage heat source first-class absorption heat pump control system according to an embodiment of the present invention includes:

[0073] Real-time calculation module: Calculate the current incremental PID output value through a PID controller;

[0074] Analysis and control module: Based on the incremental PID output value calculated by the real-time calculation module, determine whether the current heating supply of the first-stage absorption heat pump is sufficient. If insufficient, determine the current control mode. If it is a low-pressure control mode, determine whether a second-stage heat source is needed for heating based on the current incremental PID output value. If so, control the maximum opening of the first-stage heat source while determining and controlling the adjustment opening of the steam regulating valve of the second-stage heat source. If it is a high-pressure control mode, maintain the maximum opening of the first-stage heat source while determining and controlling the increase in the adjustment opening of the steam regulating valve of the second-stage heat source.

[0075] In this embodiment, the system controls two heat sources to participate in heating regulation simultaneously through a real-time calculation module and an analysis and control module. When the heat supply of one heat source is insufficient, the system maintains the maximum heat supply of the first heat source while activating the second heat source to supplement the heat supply. This solves the problem of insufficient heat source in heating and makes reasonable use of each heat source to maximize the heat supply of each heat source.

[0076] In some embodiments, the incremental PID output value is determined by PID calculations from five control sources, including the following five control sources, each with a preset target value based on heating demand. The five control sources are:

[0077] PID(YK1): Temperature control source for the outlet water temperature of the condenser B1 heating network;

[0078] PID(YK2): The outlet temperature control source for the second generator A2;

[0079] PID(YK3): The concentration control source for the second generator A2 solution;

[0080] PID (YK4): Evaporation temperature control source;

[0081] PID (YK5): Cold water outlet temperature control source;

[0082] During the heating process, the low-pressure control mode is to adjust the size of the first-stage low-pressure steam valve Y1 through PID control to enable the first-stage heat source to complete the external supply and meet the heating needs. At this time, the valve of the second-stage heat source is closed to the minimum opening and does not participate in the heating.

[0083] In the high-pressure control mode, when the heat supply from the first heat source is insufficient, and the opening of the first low-pressure steam valve Y1 is at its maximum, the size of the second high-pressure steam valve Y2 is adjusted by PID control to enable the second heat source to participate in the external supply and simultaneously complete the external supply with the first heat source.

[0084] In some embodiments, the analysis and control module may adjust the opening of valves Y1 and Y2 based on the incremental PID output value using the following control methods:

[0085] 1) When the real-time calculated values ​​of the condenser B1 heat network water outlet temperature, the second generator A2 outlet temperature, and the second generator A2 solution concentration are all less than the target values, it indicates that the current dual-stage heat source type-I absorption heat pump is insufficient to supply heat to the outside. Then, according to the real-time incremental PID output value, the opening degree of the first-stage low-pressure steam valve Y1 or the second-stage high-pressure steam valve Y2 is sequentially increased.

[0086] When the real-time calculated values ​​of the condenser B1 heat network water outlet temperature, the second generator A2 outlet temperature, or the second generator A2 solution concentration are greater than the target values, it indicates that the current dual-stage heat source type-I absorption heat pump is providing sufficient external heat. Then, based on the real-time incremental PID output value, the opening degree of the second-stage high-pressure steam valve Y2 or the first-stage low-pressure steam valve Y1 is sequentially reduced.

[0087] 2) When the real-time calculated values ​​of the evaporation temperature and the cold water outlet temperature are both greater than the target values, it indicates that the current dual-stage heat source type-I absorption heat pump is insufficient to supply heat to the outside. Then, according to the real-time incremental PID output value, the opening degree of the first-stage low-pressure steam valve Y1 or the second-stage high-pressure steam valve Y2 is sequentially increased.

[0088] When the real-time calculated value of the evaporation temperature or the cold water outlet temperature is less than the target value, it indicates that the current dual-stage heat source type-I absorption heat pump is providing sufficient external heat. Then, based on the real-time incremental PID output value, the opening degree of the second-stage high-pressure steam valve Y2 or the first-stage low-pressure steam valve Y1 is sequentially reduced.

[0089] In this embodiment, the analysis and control module realizes the switching between low-voltage control mode and high-voltage control mode based on the incremental PID output value and the current control mode, specifically including the following situations:

[0090] 1) When the heat pump unit is first started, the equipment is in cold mode. To ensure the stability of the unit, it is in low-pressure control mode at this time. One stage of heat source provides heating, and only the low-pressure steam valve Y1 participates in PID regulation. The high-pressure steam regulating valve Y2 is always closed. The opening output of the low-pressure steam regulating valve is calculated as follows:

[0091] Y1 开 =Y1C + Y1K;

[0092] Y1K=MIN(PID(YK1), PID(YK2), PID(YK3), PID(YK4), PID(YK5));

[0093] Y1max>=Y1 开 >=Y1min;

[0094] Y1Dmax >= Y1K >= Y1Dmin;

[0095] In the formula, Y1 开For the opening output of the low-pressure steam control valve Y1, Y1C is the current opening output of the first-stage steam control valve; Y1K is the incremental PID output value (the minimum value of 5 control sources); Y1max is the maximum opening of the low-pressure steam control valve in the first stage; Y1min is the minimum opening of the low-pressure steam control valve in the first stage; Y1Dmax is the maximum incremental PID action of the low-pressure steam control valve in the first stage; Y1Dmin is the minimum incremental PID action of the low-pressure steam control valve in the first stage;

[0096] 2) If none of the 5 control sources reach the target value and the opening of the low-pressure steam valve Y1 in the first stage reaches the maximum opening, it can be judged that the heat source of the low-pressure steam in the first stage is insufficient, then the high-pressure control mode is activated. The judgment conditions for activating the second-stage high-pressure steam valve Y2 are as follows:

[0097] That is, when Y1 开 = Y1max, and PV1 in PID(YK1) < SP1 - DT1, PV2 in PID(YK2) < SP2 - DT2, PV3 in PID(YK3) < SP3 - DT3, PV4 in PID(YK4) > SP4 + DT4, PV5 in PID(YK5) > SP5 + DT5, it indicates that the current heat source is insufficient, then enter the high-pressure control mode. The low-pressure steam control valve Y1 in the first stage maintains the maximum opening and no longer participates in PID regulation. The high-pressure steam control valve Y2 in the second stage participates in PID regulation; by participating in heat supply through the second-stage low-pressure steam regulation, it can stably solve the problem of insufficient heat source caused by supplying heat externally only through the first-stage heat source.

[0098] Among them:

[0099] PV1 - PV5 respectively correspond to the feedback values of the control sources of the outlet temperature of the heat network water of the current condenser B1, the feedback values of the control sources of the outlet temperature of the second generator A2, the feedback values of the control sources of the solution concentration of the second generator A2, the feedback values of the control sources of the evaporation temperature, and the feedback values of the control sources of the outlet temperature of the chilled water;

[0100] DT1 - DT5 respectively correspond to the deviation values of the target values of the control sources of the outlet temperature of the heat network water of the current condenser B1, the deviation values of the target values of the control sources of the outlet temperature of the second generator A2, the deviation values of the target values of the control sources of the solution concentration of the second generator A2, the deviation values of the target values of the control sources of the evaporation temperature, and the deviation values of the target values of the control sources of the outlet temperature of the chilled water;

[0101] SP1 - SP5 respectively correspond to the preset target values of the control sources of the outlet temperature of the heat network water of the current condenser B1, the preset target values of the control sources of the outlet temperature of the second generator A2, the preset target values of the control sources of the solution concentration of the second generator A2, the preset target values of the control sources of the evaporation temperature, and the preset target values of the control sources of the outlet temperature of the chilled water;

[0102] Y2 开= Y2C + Y2K;

[0103] Y2K = MIN(PID(YK1), PID(YK2), PID(YK3), PID(YK4), PID(YK5));

[0104] Y2max >= Y2 开 >= Y2min;

[0105] Y2Dmax >= Y2K >= Y2Dmin;

[0106] Wherein, Y2 开 is the opening output of the second-stage high-pressure steam regulating valve; Y2C is the opening output of the current second-stage steam regulating valve; Y2K is the incremental PID output value (the minimum value of 5 control sources); Y2max is the maximum opening of the second-stage high-pressure steam regulating valve; Y2min is the minimum opening of the second-stage high-pressure steam regulating valve; Y2Dmax is the maximum value of the incremental PID action of the second-stage high-pressure steam regulating valve; Y2Dmin is the minimum value of the incremental PID action of the second-stage high-pressure steam regulating valve;

[0107] 3) In the high-pressure control mode, when Y2 开 = Y2min, and PV1 > SP1 + DT1 in PID(YK1), PV2 > SP2 + DT2 in PID(YK2), PV3 > SP3 + DT3 in PID(YK3), PV4 < SP4 - DT4 in PID(YK4) or PV5 < SP5 - DT5 in PID(YK5) satisfies one of the control conditions, it means that the current heat source is sufficient, the second-stage high-pressure steam regulating valve Y2 is closed to the minimum opening and no longer participates in PID regulation, and enters the low-pressure control mode, and the first-stage low-pressure steam valve resumes PID regulation.

[0108] The embodiment of the present invention is a system embodiment corresponding to the above method embodiment. The specific operations of each module processing step can be understood by referring to the description of the method embodiment, and will not be repeated here.

[0109] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for apparatus or system embodiments, since they are basically similar to method embodiments, the description is relatively simple, and relevant parts can be referred to the description of the method embodiments. The apparatus and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0110] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A control method for a dual-stage heat source type-one absorption heat pump, characterized in that, include: The current incremental PID output value is calculated using the PID controller. Based on the currently calculated incremental PID output value, determine whether the current heat supply of the absorption heat pump is sufficient. If it is insufficient, determine the current control mode. If it is a low-pressure control mode, determine whether a second-stage heat source is needed based on the currently calculated incremental PID output value. If so, control the maximum opening of the first-stage low-pressure steam valve (Y1) while determining and controlling the adjustment opening of the second-stage high-pressure steam valve (Y2). If it is a high-pressure control mode, maintain the maximum opening of the first-stage low-pressure steam valve (Y1) while determining and controlling the increased adjustment opening of the second-stage high-pressure steam valve (Y2). The incremental PID output value is calculated through PID calculations of five control sources, each with a preset target value based on heating demand. The five control sources are: PID (YK1): Condenser (B1) heating network water outlet temperature control source; PID (YK2): The outlet temperature control source for the second generator (A2); PID (YK3): Second generator (A2) solution concentration control source; PID (YK4): Evaporation temperature control source; PID (YK5): Cold water outlet temperature control source; The switching between the low-pressure control mode and the high-pressure control mode specifically includes the following situations: 1) When none of the five control sources reach the target value, and the opening degree of the first-stage low-pressure steam valve (Y1) reaches the maximum opening degree, the high-pressure control mode is activated, and the judgment condition for activating the second-stage high-pressure steam valve (Y2) is as follows: When Y1 开 = Y1max, and in PID(YK1), PV1 < SP1 - DT1; in PID(YK2), PV2 < SP2 - DT2; in PID(YK3), PV3 < SP3 - DT3; in PID(YK4), PV4 > SP4 + DT4; in PID(YK5), PV5 > SP5 + DT5, then enter the high-pressure control mode. The low-pressure steam valve (Y1) of the first stage maintains the maximum opening, and the high-pressure steam valve (Y2) of the second stage participates in PID regulation; Among them, Y1 开 Y1max is the opening output of a low-pressure steam valve (Y1), and Y1max is the maximum opening value of a low-pressure steam valve (Y1). PV1-PV5 correspond to the current condenser (B1) hot water outlet temperature control source feedback value, the second generator (A2) outlet temperature control source feedback value, the second generator (A2) solution concentration control source feedback value, the evaporation temperature control source feedback value, and the cold water outlet temperature control source feedback value, respectively. DT1-DT5 correspond to the deviation values ​​of the target values ​​of the current condenser (B1) hot water outlet temperature control source, the second generator (A2) outlet temperature control source, the second generator (A2) solution concentration control source, the evaporation temperature control source, and the cold water outlet temperature control source, respectively. SP1-SP5 correspond to the preset target values ​​of the current condenser (B1) hot water outlet temperature control source, the preset target value of the second generator (A2) outlet temperature control source, the preset target value of the second generator (A2) solution concentration control source, the preset target value of the evaporation temperature control source, and the preset target value of the cold water outlet temperature control source, respectively. 2) In the high-pressure control mode, when Y2 开 = Y2min, and in PID(YK1), PV1 > SP1 + DT1; in PID(YK2), PV2 > SP2 + DT2; in PID(YK3), PV3 > SP3 + DT3; in PID(YK4), PV4 < SP4 - DT4; or in PID(YK5), PV5 < SP5 - DT5, when one of these control conditions is met, the second-stage high-pressure steam valve (Y2) closes to the minimum opening, enters the low-pressure control mode, and the first-stage low-pressure steam valve (Y1) resumes PID regulation; Among them, Y2 开 Y2min is the opening output of the two-stage high-pressure steam valve (Y2); Y2min is the minimum value of the two-stage high-pressure steam valve (Y2).

2. The control method for a dual-stage heat source absorption heat pump as described in claim 1, characterized in that, Adjusting the opening of a low-pressure steam valve (Y1) or a high-pressure steam valve (Y2) based on the incremental PID output value includes the following control scenarios: 1) When the real-time calculated values ​​of the condenser (B1) hot water outlet temperature, the second generator (A2) outlet temperature, and the second generator (A2) solution concentration are all less than the target values, the opening degree of the first-stage low-pressure steam valve (Y1) or the second-stage high-pressure steam valve (Y2) will be increased sequentially according to the real-time incremental PID output value. When the real-time calculated values ​​of the condenser (B1) hot water outlet temperature, the second generator (A2) outlet temperature, or the second generator (A2) solution concentration are greater than the target value, the opening degree of the second-stage high-pressure steam valve (Y2) or the first-stage low-pressure steam valve (Y1) will be reduced sequentially according to the real-time incremental PID output value. 2) When the real-time calculated values ​​of the evaporation temperature and the cold water outlet temperature are both greater than the target values, the opening of the first-stage low-pressure steam valve (Y1) or the second-stage high-pressure steam valve (Y2) will be increased sequentially according to the real-time incremental PID output value. When the real-time calculated value of the evaporation temperature or the cold water outlet temperature is less than the target value, the opening degree of the second-stage high-pressure steam valve (Y2) or the first-stage low-pressure steam valve (Y1) is sequentially reduced according to the real-time incremental PID output value.

3. A dual-stage heat source type-one absorption heat pump control system, characterized in that, include Real-time calculation module: Calculates the current incremental PID output value through the PID controller; Analysis and Control Module: Based on the incremental PID output value calculated by the real-time calculation module, determine whether the current heating supply of the absorption heat pump is sufficient. If insufficient, determine the current control mode. If it is a low-pressure control mode, determine whether a second-stage heat source is needed based on the current incremental PID output value. If so, control the maximum opening of the first-stage low-pressure steam valve (Y1) while determining and controlling the adjustment opening of the second-stage high-pressure steam valve (Y2). If it is a high-pressure control mode, maintain the maximum opening of the first-stage low-pressure steam valve (Y1) while determining and controlling the increase in the adjustment opening of the second-stage high-pressure steam valve (Y2). The real-time calculation module calculates the incremental PID output value through PID calculations from five control sources, each with a preset target value based on heating demand. The five control sources are: PID (YK1): Condenser (B1) heating network water outlet temperature control source; PID (YK2): The outlet temperature control source for the second generator (A2); PID (YK3): Second generator (A2) solution concentration control source; PID (YK4): Evaporation temperature control source; PID (YK5): Cold water outlet temperature control source; The analysis and control module switches between low-voltage and high-voltage control modes based on the incremental PID output value and the current control mode, specifically including the following situations: 1) When none of the five control sources reach the target value, and the opening degree of the first-stage low-pressure steam valve (Y1) reaches the maximum opening degree, the high-pressure control mode is activated, and the judgment condition for activating the second-stage high-pressure steam valve (Y2) is as follows: When Y1 开 = Y1max, and PV1 in PID(YK1) < SP1 - DT1, PV2 in PID(YK2) < SP2 - DT2, PV3 in PID(YK3) < SP3 - DT3, PV4 in PID(YK4) > SP4 + DT4, PV5 in PID(YK5) > SP5 + DT5, then enter the high - pressure control mode. The first - stage low - pressure steam valve (Y1) maintains the maximum opening, and the second - stage high - pressure steam valve (Y2) participates in PID regulation; Among them, Y1 开 Y1max is the opening output of a low-pressure steam valve (Y1), and Y1max is the maximum opening value of a low-pressure steam valve (Y1). PV1-PV5 correspond to the current condenser (B1) hot water outlet temperature control source feedback value, the second generator (A2) outlet temperature control source feedback value, the second generator (A2) solution concentration control source feedback value, the evaporation temperature control source feedback value, and the cold water outlet temperature control source feedback value, respectively. DT1-DT5 correspond to the deviation values ​​of the target values ​​of the current condenser (B1) hot water outlet temperature control source, the second generator (A2) outlet temperature control source, the second generator (A2) solution concentration control source, the evaporation temperature control source, and the cold water outlet temperature control source, respectively. SP1 - SP5 respectively correspond to the preset target value of the heat network water outlet temperature control source of the current condenser (B1), the preset target value of the outlet temperature control source of the second generator (A2), the preset target value of the solution concentration control source of the second generator (A2), the preset target value of the evaporation temperature control source, and the preset target value of the chilled water outlet temperature control source; 2) In the high-pressure control mode, when Y2 开 = Y2min, and one of the following controls is satisfied: in PID (YK1), PV1 > SP1 + DT1; in PID (YK2), PV2 > SP2 + DT2; in PID (YK3), PV3 > SP3 + DT3; in PID (YK4), PV4 < SP4 - DT4; or in PID (YK5), PV5 < SP5 - DT5, the second-stage high-pressure steam valve (Y2) closes to the minimum opening degree and enters the low-pressure control mode, and the first-stage low-pressure steam valve (Y1) resumes PID regulation; where Y2 开 is the opening degree output of the second-stage high-pressure steam valve (Y2); Y2min is the minimum value of the second-stage high-pressure steam valve (Y2).

4. The dual-stage heat source type-one absorption heat pump control system as described in claim 3, characterized in that, The analysis and control module adjusts the opening of the first-stage low-pressure steam valve (Y1) or the second-stage high-pressure steam valve (Y2) based on the incremental PID output value, including the following control scenarios: 1) When the real-time calculated values ​​of the condenser (B1) hot water outlet temperature, the second generator (A2) outlet temperature, and the second generator (A2) solution concentration are all less than the target values, the opening degree of the first-stage low-pressure steam valve (Y1) or the second-stage high-pressure steam valve (Y2) will be increased sequentially according to the real-time incremental PID output value. When the real-time calculated values ​​of the condenser (B1) hot water outlet temperature, the second generator (A2) outlet temperature, or the solution concentration are greater than the target value, the opening of the second-stage high-pressure steam valve (Y2) or the first-stage low-pressure steam valve (Y1) will be reduced sequentially according to the real-time incremental PID output value. 2) When the real-time calculated values ​​of the evaporation temperature and the cold water outlet temperature are both greater than the target values, the opening of the first-stage low-pressure steam valve (Y1) or the second-stage high-pressure steam valve (Y2) will be increased sequentially according to the real-time incremental PID output value. When the real-time calculated value of the evaporation temperature or the cold water outlet temperature is less than the target value, the opening degree of the second-stage high-pressure steam valve (Y2) or the first-stage low-pressure steam valve (Y1) is sequentially reduced according to the real-time incremental PID output value.

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