A control method and system of a dual-source air injection and gas supplementing heat pump system

Abstract

The application discloses a control method and system of a double-source air-supplementing jet-incremental-enhalpy heat pump system. The method comprises the following steps: calculating the total pressure drop of the system according to the condensing pressure and the first evaporation pressure, and calculating the first expansion valve target pressure drop, the auxiliary valve target pressure drop and the second expansion valve target pressure drop, and the flash evaporator target pressure according to the total pressure drop of the system, the condensing pressure and the first evaporation pressure, so as to establish a compression ratio adaptive iterative partial pressure calculation model based on the pressure, realize dynamic optimal distribution of three-stage throttling pressure drops, and reduce the throttling loss. According to the flash evaporator target pressure, the auxiliary valve target pressure drop and the second expansion valve target pressure drop, an incremental PID control algorithm is adopted to calculate the target opening degrees of the first expansion valve, the auxiliary valve and the second expansion valve respectively, so as to control the first expansion valve, the auxiliary valve and the second expansion valve to operate according to the target opening degrees respectively. The three valves are independently decoupled by the incremental PID / PI control architecture, and the technical problems of multi-valve coupling oscillation and overshoot are solved.

Description

Technical Field

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

[0002] Enhanced Vapor Injection (EVI) technology effectively improves the heating capacity and operational reliability of air-source heat pumps under low-temperature conditions by introducing makeup gas into the intermediate cavity of the compressor, and has been widely used in the heat pump field. Based on the different makeup gas methods, existing EVI systems are mainly divided into two categories: flash evaporator makeup gas type and economizer makeup gas type. The flash evaporator makeup gas type system obtains intermediate pressure gas through gas-liquid separation after a single throttling cycle; the economizer makeup gas type system achieves subcooling and makeup gas through heat exchange in the main and auxiliary loops.

[0003] Existing control schemes for jet-induced enthalpy heat pumps still have the following inherent drawbacks:

[0004] First, the control model is coarse and cannot accurately adapt to multi-stage throttling topologies. Existing technologies mostly support single-stage throttling or a single gas supply structure, lacking dedicated pressure-dividing control logic for the three-stage gradient throttling of "expansion valve EXV1 - flash evaporator - auxiliary valve - economizer - expansion valve EXV2". Due to the mutual coupling and interference of multi-stage throttling, the system pressure and temperature fluctuate greatly, resulting in poor operational stability.

[0005] Second, the lack of quantitative mathematical models makes it difficult to implement in engineering. Traditional control schemes generally rely on empirical thresholds or qualitative judgments, lacking clear iterative calculation formulas, parameter convergence logic, and real-time dynamic matching algorithms.

[0006] Third, the dual-source gas supply regulation is unbalanced, resulting in poor adaptability to operating conditions. Existing dual-source gas supply schemes mostly adopt isobaric gas supply or fixed opening adjustment, which cannot achieve the stratified gradient enthalpy increase of "low-pressure initial cooling of flash evaporator + high-pressure deep cooling of economizer", resulting in low heating efficiency in extremely cold conditions.

[0007] Fourth, there is no decoupling mechanism for multi-valve coupling. The three-stage throttle valve linkage regulation has strong coupling interference. Traditional single-loop proportional-integral-derivative (PID) regulation is prone to oscillation, overshoot and large steady-state error, and lacks a dedicated decoupling control strategy.

[0008] Both of the above-mentioned gas replenishment methods use a single gas replenishment source, and there is no technical solution that couples the flash evaporator and economizer dual-source gas replenishment into the same system. Summary of the Invention

[0009] This invention provides a control method and system for a dual-source gas injection enthalpy-increasing heat pump system, which solves the technical problems of coarse control models, lack of quantitative formulas, dual-source gas injection imbalance, and multi-valve coupling oscillation in the prior art, and achieves efficient, stable, and adaptive operation under all working conditions.

[0010] According to one aspect of the present invention, a control method for a dual-source injection-induced enthalpy-increasing heat pump system is provided, the system comprising a first expansion valve, a flash evaporator, an auxiliary valve, an economizer, a second expansion valve, and a finned heat exchanger; the method comprising:

[0011] Based on the preset periodic acquisition of system temperature and pressure parameters, the temperature and pressure parameters include condensation pressure and first evaporation pressure;

[0012] Based on the condensing pressure and the first evaporating pressure, calculate the total system pressure drop, and based on the total system pressure drop, the condensing pressure and the first evaporating pressure, calculate the target pressure drop of the first expansion valve, the target pressure drop of the auxiliary valve and the target pressure drop of the second expansion valve, as well as the target pressure of the flash evaporator;

[0013] Based on the target pressure of the flash evaporator, the target pressure drop of the auxiliary valve, and the target pressure drop of the second expansion valve, an incremental PID control algorithm is used to calculate the target opening degree of the first expansion valve, the auxiliary valve, and the second expansion valve, so as to control the first expansion valve, the auxiliary valve, and the second expansion valve to operate according to their respective target opening degrees.

[0014] Optionally, based on the condensing pressure and the first evaporating pressure, the total system pressure drop is calculated, and based on the total system pressure drop, the condensing pressure, and the first evaporating pressure, the target pressure drop of the first expansion valve, the target pressure drop of the auxiliary valve, and the target pressure of the second expansion valve are calculated, as well as the flash evaporator target pressure, including:

[0015] Calculate the difference between the condensing pressure and the first evaporating pressure, and use the absolute value of the difference as the total pressure drop of the system;

[0016] Calculate the target pressure drop of the first expansion valve and the target pressure drop of the auxiliary valve based on the total system pressure drop, the condensing pressure, and the first evaporating pressure.

[0017] Calculate the target pressure drop of the second expansion valve based on the total system pressure drop, the target pressure drop of the first expansion valve, and the target pressure drop of the auxiliary valve.

[0018] Calculate the target pressure of the flash evaporator based on the target pressure drop of the first expansion valve and the condensing pressure.

[0019] Optionally, the total system pressure drop can be calculated using the following formula:

[0020] In the formula, For the total system voltage drop, For condensation pressure, This is the first evaporation pressure;

[0021] The target pressure drop of the first expansion valve is calculated using the following formula:

[0022] In the formula, The target pressure drop for the first expansion valve;

[0023] The target pressure drop of the auxiliary valve is calculated using the following formula:

[0024] In the formula, For auxiliary valve target pressure drop;

[0025] The target pressure drop of the second expansion valve is calculated using the following formula:

[0026] In the formula, The target pressure drop for the second expansion valve;

[0027] The target pressure of the flash evaporator is calculated using the following formula:

[0028] In the formula, The target pressure for the flash evaporator.

[0029] Optionally, the temperature and pressure parameters may also include the second evaporation pressure, compressor suction temperature, economizer outlet liquid phase temperature, economizer outlet subcooling, and finned heat exchanger suction superheat.

[0030] Based on the target pressure of the flash evaporator, the target pressure drop of the auxiliary valve, and the target pressure drop of the second expansion valve, an incremental PID control algorithm is used to calculate the target opening degree of the first expansion valve, the auxiliary valve, and the second expansion valve, including:

[0031] The target opening of the first expansion valve is calculated using the following formula:

[0032] In the formula, for The target opening degree of the first expansion valve at time t, and the constraint range of the target opening degree of the first expansion valve are: , for The target opening degree of the first expansion valve at any given time. This represents the increment of the opening of the first expansion valve; where, In the formula, , and These are the proportional, integral, and derivative coefficients of the first expansion valve, respectively, and their values ​​are... , For the first expansion valve The first deviation in time, For the first expansion valve The first deviation in time, For the first expansion valve The first deviation in time; In the formula, The target pressure for the flash evaporator, for The second evaporation pressure at that moment;

[0033] The target opening degree of the auxiliary valve is calculated using the following formula:

[0034] In the formula, for The target opening degree of the auxiliary valve at any given time, and the constraint range of the target opening degree of the auxiliary valve is: , for The target opening degree of the auxiliary valve at any given time. For the auxiliary valve opening increment; among which, In the formula, , These are the proportional and integral coefficients of the auxiliary valve, with values ​​of [values ​​to be filled in]. , Auxiliary valve The second deviation in time, Auxiliary valve The second deviation in time; In the formula, The target value for the supercooling of the export of the economizer. for The current economic export overcooling; In the formula, This is the saturation temperature corresponding to the second evaporation pressure. The outlet liquid phase temperature of the economizer;

[0035] The target opening degree of the second expansion valve is calculated using the following formula:

[0036] In the formula, for The target opening degree of the second expansion valve at time t, the constraint range of the target opening degree of the second expansion valve is t. , for The target opening degree of the second expansion valve at any given time. This is the increment of the second expansion valve opening; where, In the formula, , and These are the proportional, integral, and derivative coefficients of the second expansion valve, with values ​​of [values ​​to be filled in]. , For the second expansion valve The third deviation in time, For the second expansion valve The third deviation in time, For the second expansion valve The third deviation in time; In the formula, The target value for the intake superheat of the finned heat exchanger. for The constant temperature of the finned heat exchanger intake superheat; In the formula, This refers to the compressor suction temperature. This is the saturation temperature corresponding to the first evaporation pressure.

[0037] Optionally, the temperature and pressure parameters also include ambient temperature; before calculating the total system pressure drop based on the condensing pressure and the first evaporating pressure, the following is also included:

[0038] The heating condition is determined based on the ambient temperature, condensing pressure, and first evaporating pressure.

[0039] Optionally, the heating operating conditions can be determined based on ambient temperature, condensing pressure, and first evaporating pressure, including:

[0040] When satisfied At that time, it was determined to be an extremely cold heating condition; among them, The ambient temperature;

[0041] When satisfied At that time, it was determined to be a normal temperature heating condition;

[0042] When satisfied When the extreme cold heating condition is reached, the control boundary shall be followed.

[0043] When satisfied If the condition is not met, the heating mode determination will be exited.

[0044] Optionally, before calculating the target opening degree of the first expansion valve, the auxiliary valve, and the second expansion valve using an incremental PID control algorithm based on the target pressure of the flash evaporator, the target pressure drop of the auxiliary valve, and the target pressure drop of the second expansion valve, the method further includes:

[0045] Based on the ambient temperature, condensing pressure, and first evaporating pressure, calculate the flash evaporator makeup gas ratio and the economizer makeup gas ratio; wherein, the flash evaporator makeup gas ratio satisfies the following formula:

[0046] In the formula, The proportion of gas supplied to the flash evaporator;

[0047] The fuel injection ratio of the economizer must satisfy the following formula:

[0048] In the formula, The proportion of fuel added to the economizer;

[0049] Basic boundary hard constraints must satisfy Under extremely cold heating conditions, it must meet the following requirements. .

[0050] Optionally, the temperature and pressure parameters also include the compressor discharge temperature; after calculating the target opening degree of the first expansion valve, the auxiliary valve, and the second expansion valve using an incremental PID control algorithm based on the flash evaporator target pressure, the auxiliary valve target pressure drop, and the second expansion valve target pressure drop, the method further includes:

[0051] When satisfied At the same time, increase the proportion of gas supplementation for the economizer; among which, This refers to the compressor discharge temperature.

[0052] When satisfied At that time, the unit's operating frequency decreases at a slope of 0.5 Hz / ℃;

[0053] When satisfied At that time, the shutdown protection is triggered.

[0054] Optionally, based on the target pressure of the flash evaporator, the target pressure drop of the auxiliary valve, and the target pressure drop of the second expansion valve, an incremental PID control algorithm is used to calculate the target opening degree of the first expansion valve, the auxiliary valve, and the second expansion valve, including:

[0055] The formula is applied based on the first evaporation pressure and the second evaporation pressure. Calculate the actual pressure drop of the auxiliary valve; where, The actual pressure drop of the auxiliary valve;

[0056] When the formula is satisfied At that time, the integral term limit value of the auxiliary valve PI control algorithm is triggered by... Dynamic compression to ;

[0057] Calculate the actual pressure drop of the second expansion valve based on the second evaporation pressure and the preset saturation pressure;

[0058] When the deviation between the actual pressure drop of the second expansion valve and the target pressure drop of the second expansion valve exceeds ±18% for more than 30 seconds, an alarm is triggered and the second expansion valve is switched to the preset safe opening degree.

[0059] According to another aspect of the present invention, a dual-source injection enthalpy-increasing heat pump system is provided, including a compressor, a four-way valve, a solenoid valve, a plate heat exchanger, and a buffer, and further including a first expansion valve, a flash evaporator, an auxiliary valve, an economizer, a second expansion valve, and a finned heat exchanger.

[0060] The technical solution provided by this invention calculates the total system pressure drop based on the condensing pressure and the first evaporating pressure. Based on the total system pressure drop, condensing pressure, and the first evaporating pressure, it calculates the target pressure drop of the first expansion valve, the target pressure drop of the auxiliary valve, and the target pressure of the second expansion valve, as well as the target pressure of the flash evaporator. This establishes an adaptive iterative pressure distribution calculation model based on the compression ratio to calculate the target pressure drop of each of the three throttling elements, achieving dynamic optimal allocation of the three-stage throttling pressure drop and reducing throttling losses. Based on the target pressure of the flash evaporator, the target pressure drop of the auxiliary valve, and the target pressure drop of the second expansion valve, an incremental PID control algorithm is used to calculate the target opening degree of each of the first expansion valve, auxiliary valve, and second expansion valve, controlling them to operate according to their respective target opening degrees. This achieves a three-valve independent decoupled incremental PID / PI control architecture, solving the technical problems of multi-valve coupling oscillation, overshoot, and large steady-state error. The technical solution provided by this invention can achieve efficient, stable, and adaptive operation of the system under all operating conditions.

[0061] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0062] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0063] Figure 1 A flowchart illustrating a control method for a dual-source injection jet enthalpy-enhancing heat pump system provided in an embodiment of the present invention;

[0064] Figure 2 This is a schematic diagram of the structure of the dual-source injection jet enthalpy-enhancing heat pump system provided in an embodiment of the present invention;

[0065] Figure 3 A control device for a dual-source injection jet enthalpy-enhancing heat pump system provided in an embodiment of the present invention;

[0066] Figure 4 This is a schematic diagram of the electronic device used in the control method of a dual-source injection enthalpy-enhancing heat pump system provided in an embodiment of the present invention. Detailed Implementation

[0067] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0068] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0069] Figure 1 The flowchart illustrates a control method for a dual-source injection jet enthalpy-enhancing heat pump system provided in an embodiment of the present invention. This method can be executed by a control device for the dual-source injection jet enthalpy-enhancing heat pump system. This device can be implemented in hardware and / or software and can be configured in any electronic device with communication capabilities. Figure 2 This is a schematic diagram of the dual-source injection jet enthalpy-enhancing heat pump system provided in an embodiment of the present invention. (See attached diagram.) Figure 2 The system includes a compressor, a four-way valve, a solenoid valve, a plate heat exchanger, and a buffer. It also includes a first expansion valve EXV1, a flash evaporator, an auxiliary valve, an economizer, a second expansion valve EXV2, and a finned heat exchanger. See also... Figure 1 The method includes:

[0070] S110. Collect system temperature and pressure parameters based on a preset cycle. The temperature and pressure parameters include condensation pressure and first evaporation pressure.

[0071] The "system temperature and pressure parameter acquisition based on a preset cycle" refers to the system controller cyclically collecting refrigerant temperature and pressure parameters at key pipeline nodes of the heat pump system according to a pre-set fixed sampling cycle after the unit enters steady-state heating operation. All collected parameters will serve as real-time inputs for subsequent operating condition determination, three-stage throttling pressure calculation, dual-source gas supply ratio adjustment, and valve closed-loop control, providing a data foundation for the system's full-process quantitative control. In this embodiment of the invention, a preset cycle of 10 seconds is used for illustration, but this invention does not limit this value. The preset cycle can be preset according to requirements.

[0072] The condensing pressure corresponds to the refrigerant working pressure on the high-pressure side of the system, that is, the working pressure of the refrigerant in the condensing heat exchange stage. Its detection point can be set on the compressor exhaust pipe to characterize the operating status of the high-pressure end of the system. Its value can intuitively reflect the matching degree between the system heating load and the condensing heat exchange capacity.

[0073] The first evaporation pressure corresponds to the refrigerant working pressure on the low-pressure side of the system, that is, the working pressure of the refrigerant in the evaporation heat absorption stage. Its detection point can be set on the compressor suction port pipeline to characterize the operating status of the low-pressure side of the system. Its value can intuitively reflect the matching status between the evaporator heat exchange load and the refrigerant circulation flow.

[0074] Specifically, the condensation pressure and the first evaporation pressure can be collected by a pressure sensor based on a preset cycle.

[0075] S120. Calculate the total system pressure drop based on the condensing pressure and the first evaporating pressure, and calculate the target pressure drop of the first expansion valve, the target pressure drop of the auxiliary valve, and the target pressure of the second expansion valve, as well as the target pressure of the flash evaporator, based on the total system pressure drop, the condensing pressure, and the first evaporating pressure.

[0076] Specifically, after acquiring the system temperature and pressure parameters, the controller calculates the compression ratio based on the condensing pressure and the first evaporating pressure and executes a three-stage gradient pressure distribution to determine the target pressure drop of the first expansion valve, the auxiliary valve, and the second expansion valve, as well as the target pressure of the flash evaporator.

[0077] The total system pressure drop is the difference between the condensing pressure and the first evaporating pressure. It represents the total pressure drop of the refrigerant from the high-pressure condensing end of the system through all throttling elements to the low-pressure evaporating end, and serves as the overall benchmark for the three-stage throttling pressure drop distribution. The magnitude of the total pressure drop directly reflects the high-low pressure difference level under the current operating conditions of the system, and it changes dynamically with variations in ambient temperature, heating load, and compressor operating frequency.

[0078] This step employs a compression ratio-adaptive pressure distribution model to allocate the total pressure drop in three stages, where the compression ratio is the ratio of the condensing pressure to the first evaporating pressure. Unlike fixed-ratio pressure drop allocation methods, this model dynamically adjusts the pressure drop percentage of each throttling stage based on the real-time compression ratio. This ensures that the pressure drop distribution of the three throttling stages always adapts to the refrigerant flow characteristics under the current operating conditions, minimizing energy loss during the throttling process while maintaining effective flash vapor-liquid separation and economizer subcooling injection.

[0079] The target pressure drop of the first expansion valve is the total system pressure drop multiplied by the first partial pressure coefficient, which increases linearly and slightly with the increase of the system compression ratio. The first expansion valve performs the first-stage throttling function, reducing the pressure of the high-pressure liquid refrigerant at condensation to the intermediate pressure range of flash evaporation, causing some of the refrigerant to flash into a gaseous state, providing a gas source for the flash evaporator. Based on the target pressure drop of the first expansion valve, the target pressure of the flash evaporator can be calculated, that is, the target pressure of the flash evaporator equals the condensation pressure minus the target pressure drop of the first expansion valve. The target pressure of the flash evaporator directly determines the pressure level of the flash evaporation gas supply and the enthalpy of the gaseous refrigerant, and also serves as the target setpoint for the closed-loop pressure control of the first expansion valve.

[0080] The target pressure drop of the auxiliary valve is the total system pressure drop multiplied by the second partial pressure coefficient. This second partial pressure coefficient also increases linearly and slightly with the increase of the system compression ratio, and its proportion is lower than that of the pressure drop proportion of the first expansion valve. The auxiliary valve performs a second-stage throttling function, reducing the pressure of the liquid refrigerant flowing out of the flash evaporator before sending it to the economizer auxiliary circuit, providing a medium-pressure gas source for the economizer's deep gas replenishment. The target pressure drop of the auxiliary valve also serves as a differential pressure verification benchmark, used to compare with the actual differential pressure value before and after the auxiliary valve. When the actual differential pressure deviates from the target value beyond the allowable range, adaptive adjustment of the control parameters is triggered to avoid integral saturation and control oscillation caused by differential pressure imbalance.

[0081] The target pressure drop of the second expansion valve is obtained by subtracting the target pressure drop of the first expansion valve and the target pressure drop of the auxiliary valve from the total system pressure drop. A minimum pressure drop percentage is set as a lower limit constraint to ensure sufficient pressure reduction margin in the final stage of throttling, preventing insufficient evaporator supply pressure. The second expansion valve performs the third-stage throttling function, reducing the pressure of the liquid refrigerant after subcooling by the economizer to the evaporation pressure before sending it to the evaporator for evaporation and heat absorption. The target pressure drop of the second expansion valve can be used as a threshold for verifying operational rationality. By comparing the actual pressure drop of the second expansion valve with the target pressure drop, it can be determined whether the system refrigerant flow is abnormal, enabling fault warning and safety protection.

[0082] Through the above three-stage gradient pressure distribution calculation, the pressure drop of the three-stage throttling structure of "first expansion valve - flash evaporator - auxiliary valve - economizer - second expansion valve" can be accurately distributed, forming a pressure hierarchy with distinct gradients. This provides a stable pressure foundation for dual-source stratified gas replenishment, while improving the system's operating efficiency and stability under all operating conditions.

[0083] S130. Based on the target pressure of the flash evaporator, the target pressure drop of the auxiliary valve, and the target pressure drop of the second expansion valve, an incremental PID control algorithm is used to calculate the target opening degree of the first expansion valve, the auxiliary valve, and the second expansion valve, so as to control the first expansion valve, the auxiliary valve, and the second expansion valve to operate according to their respective target opening degrees.

[0084] Specifically, based on the target pressure of the flash evaporator, the target pressure drop of the auxiliary valve, and the target pressure drop of the second expansion valve, the controller establishes independent closed-loop control branches for the first expansion valve, the auxiliary valve, and the second expansion valve, respectively. It uses incremental PID or PI control algorithms to calculate the target opening degree of each valve in real time and drives the valve to perform adjustment according to the target opening degree, thereby achieving decoupled and precise control of the three-stage throttling process.

[0085] For the first expansion valve, the control objective is to ensure that the actual pressure of the flash evaporator accurately follows the target pressure of the flash evaporator. The controller employs an incremental PID control algorithm for closed-loop calculation. Within each sampling period, the controller calculates the deviation between the target pressure of the flash evaporator and the measured intermediate flash pressure. Combining this with historical deviation data from the previous two sampling periods, it performs incremental calculations on the proportional, integral, and derivative terms to obtain the opening increment of the first expansion valve in the current period. This opening increment is then added to the actual opening of the first expansion valve in the previous period to obtain the target opening for the current period. The output of the incremental control algorithm is the change in opening rather than the absolute opening value, enabling seamless switching during operating condition changes and parameter adjustments, avoiding significant system pressure fluctuations caused by sudden valve opening changes. Simultaneously, the controller sets upper and lower limits for the target opening of the first expansion valve and sets a threshold limit for the integral calculation term to prevent overshoot caused by integral saturation, ensuring stable and controlled intermediate flash pressure.

[0086] For the auxiliary valve, the control objective is to maintain the subcooling at the economizer outlet at a preset value. The controller uses an incremental PI control algorithm for closed-loop calculation, eliminating the derivative term to improve the smoothness of steady-state operation. The controller first calculates the actual subcooling based on the refrigerant saturation temperature corresponding to the flash intermediate pressure and the measured liquid phase temperature at the economizer outlet. Then, the difference between the preset subcooling and the actual subcooling is used as the control deviation. This deviation is then used for incremental calculations of the proportional and integral terms to obtain the auxiliary valve opening increment, which is then superimposed with historical opening values ​​to obtain the target opening for the current cycle. The auxiliary valve adjusts its own opening to change the refrigerant flow in the economizer's auxiliary circuit, thereby adjusting the heat exchange intensity of the economizer and achieving precise control of the subcooling. Simultaneously, the target pressure drop of the auxiliary valve serves as a differential pressure verification benchmark. When the deviation between the actual differential pressure before and after the auxiliary valve and the target pressure drop exceeds a preset range, the controller dynamically compresses the limit range of the integral term to suppress integral saturation and adjustment oscillations caused by differential pressure imbalance, improving the operational stability of the secondary throttling system. In this embodiment, an economizer outlet subcooling of 8°C is used as the control objective; however, this invention does not limit this.

[0087] For the second expansion valve, the control objective is to maintain the suction superheat of the finned heat exchanger at a preset value. The controller uses an incremental PID control algorithm for closed-loop calculation. The controller first calculates the actual suction superheat based on the refrigerant saturation temperature corresponding to the evaporation pressure and the measured temperature at the compressor suction port. Then, the difference between the preset superheat and the actual superheat is used as the control deviation, which is used to obtain the opening increment of the second expansion valve through incremental PID calculation. This deviation is then superimposed with historical opening values ​​to obtain the target opening for the current period. The second expansion valve adjusts the refrigerant flow rate into the evaporator to stabilize the suction superheat within a reasonable range, ensuring evaporator heat exchange efficiency while preventing liquid carryover in the compressor suction. The controller also sets operating range constraints and integral limits for the target opening of the second expansion valve to ensure safe and reliable system operation. This embodiment uses a finned heat exchanger suction superheat of 5°C as the control objective, but this invention does not limit this.

[0088] By configuring independent controlled objects and control loops for each of the three valves, the adjustment actions of each valve do not interfere with each other. This eliminates the coupling effect between the three-stage throttling valves from the control architecture perspective, effectively solving the problems of oscillation, overshoot, and large steady-state error that are prone to occur in traditional multi-valve linkage regulation, and realizing stable, accurate, and adaptive operation of the three-stage throttling under all working conditions.

[0089] The technical solution provided by this invention calculates the total system pressure drop based on the condensing pressure and the first evaporating pressure. Based on the total system pressure drop, condensing pressure, and the first evaporating pressure, it calculates the target pressure drop of the first expansion valve, the target pressure drop of the auxiliary valve, and the target pressure of the second expansion valve, as well as the target pressure of the flash evaporator. This establishes an adaptive iterative pressure distribution calculation model based on the compression ratio to calculate the target pressure drop of each of the three throttling elements, achieving dynamic optimal allocation of the three-stage throttling pressure drop and reducing throttling losses. Based on the target pressure of the flash evaporator, the target pressure drop of the auxiliary valve, and the target pressure drop of the second expansion valve, an incremental PID control algorithm is used to calculate the target opening degree of each of the first expansion valve, auxiliary valve, and second expansion valve, controlling them to operate according to their respective target opening degrees. This achieves a three-valve independent decoupled incremental PID / PI control architecture, solving the technical problems of multi-valve coupling oscillation, overshoot, and large steady-state error. The technical solution provided by this invention can achieve efficient, stable, and adaptive operation of the system under all operating conditions.

[0090] In some other embodiments, optionally, S120 specifically includes:

[0091] S1201. Calculate the difference between the condensing pressure and the first evaporating pressure, and take the absolute value of the difference as the total pressure drop of the system.

[0092] Specifically, the total system pressure drop is calculated using the following formula:

[0093] In the formula, For the total system voltage drop, For condensation pressure, This is the first evaporation pressure.

[0094] S1202. Calculate the target pressure drop of the first expansion valve and the target pressure drop of the auxiliary valve based on the total system pressure drop, condensing pressure and first evaporating pressure.

[0095] Specifically, the target pressure drop of the first expansion valve is calculated using the following formula:

[0096] In the formula, The target pressure drop for the first expansion valve.

[0097] The target pressure drop of the auxiliary valve is calculated using the following formula:

[0098] In the formula, The target pressure drop for the auxiliary valve.

[0099] Among them, the target pressure drop of the auxiliary valve As the differential pressure verification benchmark for the auxiliary valve integral limit: the controller uses the formula based on the first evaporation pressure and the second evaporation pressure. Calculate the actual pressure drop of the auxiliary valve; where, The actual pressure drop of the auxiliary valve. This is the second evaporation pressure; since, in engineering practice, the main inlet pressure of the economizer is approximately equal to the first evaporation pressure. Therefore, the second evaporation pressure With the first evaporation pressure The difference represents the actual pressure drop of the auxiliary valve.

[0100] When the formula is satisfied At that time, the integral term limit value of the auxiliary valve PI control algorithm is triggered by... Dynamic compression to To prevent pressure imbalance from causing integral saturation and over-adjustment.

[0101] S1203. Calculate the target pressure drop of the second expansion valve based on the total system pressure drop, the target pressure drop of the first expansion valve, and the target pressure drop of the auxiliary valve.

[0102] Specifically, the target pressure drop of the second expansion valve is calculated using the following formula:

[0103] In the formula, The target pressure drop for the second expansion valve.

[0104] Among them, the target pressure drop of the second expansion valve The threshold for verifying the reasonableness of the opening of the second expansion valve EXV2 is determined by the following formula: based on the second evaporation pressure and the preset saturation pressure. Calculate the actual pressure drop of the second expansion valve, where, The preset saturation pressure; when the actual pressure drop of the second expansion valve is equal to the target pressure drop of the second expansion valve... If the deviation exceeds ±18% for 30 seconds, it is determined that the system refrigerant flow is abnormal or there is a refrigerant shortage, triggering an alarm and switching the second expansion valve to the preset safe opening degree. The preset safe opening degree is 50%. The preset saturation pressure can be preset according to the saturation pressure corresponding to the finned heat exchanger coil temperature.

[0105] S1204. Calculate the target pressure of the flash evaporator based on the target pressure drop of the first expansion valve and the condensing pressure.

[0106] Specifically, the target pressure of the flash evaporator is calculated using the following formula:

[0107] In the formula, The target pressure for the flash evaporator.

[0108] In some other embodiments, the temperature and pressure parameters may optionally include a second evaporation pressure. Compressor suction temperature Economizer outlet liquid phase temperature Economic equipment export undercooling and finned heat exchanger suction superheat S130 specifically includes:

[0109] S1301. The target opening degree of the first expansion valve is calculated using the following formula:

[0110] In the formula, for The target opening degree of the first expansion valve at time t, and the constraint range of the target opening degree of the first expansion valve are: , for The target opening degree of the first expansion valve at any given time. This represents the increment of the opening of the first expansion valve; where, In the formula, , and These are the proportional, integral, and derivative coefficients of the first expansion valve, respectively, and their values ​​are... , For the first expansion valve The first deviation in time, For the first expansion valve The first deviation in time, For the first expansion valve The first deviation in time; In the formula, The target pressure for the flash evaporator, for The second evaporation pressure at that moment.

[0111] In extreme cold heating conditions, the lower limit of the target opening of the first expansion valve is dynamically increased from 15% to 20% to increase the refrigerant flow on the low-pressure side and prevent evaporator liquid shortage. The integral term of this step is limited to ±5℃·s.

[0112] S1302. The target opening degree of the auxiliary valve is calculated using the following formula:

[0113] In the formula, for The target opening degree of the auxiliary valve at any given time, and the constraint range of the target opening degree of the auxiliary valve is: , for The target opening degree of the auxiliary valve at any given time. For the auxiliary valve opening increment; among which, In the formula, , These are the proportional and integral coefficients of the auxiliary valve, with values ​​of [values ​​to be filled in]. , Auxiliary valve The second deviation in time, Auxiliary valve The second deviation in time; In the formula, The target value for the supercooling of the export of the economizer. for The current economic export overcooling; In the formula, This is the saturation temperature corresponding to the second evaporation pressure. The outlet liquid phase temperature of the economizer.

[0114] In this step, the integral term is limited to ±3℃·s. When the actual pressure drop of the auxiliary valve deviates from the target pressure drop ΔP2 of the auxiliary valve by more than ±12%, the limited compression is triggered.

[0115] S1303. The target opening degree of the second expansion valve is calculated using the following formula:

[0116] In the formula, for The target opening degree of the second expansion valve at time t, the constraint range of the target opening degree of the second expansion valve is t. , for The target opening degree of the second expansion valve at any given time. This is the increment of the second expansion valve opening; where, In the formula, , and These are the proportional, integral, and derivative coefficients of the second expansion valve, with values ​​of [values ​​to be filled in]. , For the second expansion valve The third deviation in time, For the second expansion valve The third deviation in time, For the second expansion valve The third deviation in time; In the formula, The target value for the intake superheat of the finned heat exchanger. for The constant temperature of the finned heat exchanger intake superheat; In the formula, This refers to the compressor suction temperature. This is the saturation temperature corresponding to the first evaporation pressure.

[0117] In this step, the integral term is limited to ±5℃·s.

[0118] The controller has a pre-installed R410A refrigerant saturation temperature-pressure correspondence table. The corresponding saturation temperature can be looked up using linear interpolation. If the refrigerant is changed, the corresponding property table needs to be re-programmed.

[0119] In some other embodiments, the temperature and pressure parameters may optionally include ambient temperature. Before S1201, it also includes:

[0120] S1201a. Determine the heating condition based on the ambient temperature, condensing pressure, and first evaporating pressure.

[0121] Specifically, when the following conditions are met At that time, it was determined to be an extremely cold heating condition; among them, For ambient temperature; when the following conditions are met When the conditions are met, it is determined to be a normal temperature heating condition; when the conditions are met... When the conditions are met, the control boundary for extreme cold heating will be followed; when the conditions are satisfied... If the condition is not met, the heating mode determination will be exited.

[0122] When the operating condition switches from normal temperature heating to extreme cold heating, the controller performs a "smooth transition of valve opening": the current opening of the three valves changes at a rate not exceeding 10% of the current opening every 10 seconds to transition to the target opening under the new operating condition, so as to avoid sudden changes in operating condition that cause violent fluctuations in system pressure.

[0123] In some other embodiments, optionally, prior to S130, the following steps are also included:

[0124] S130a. Based on the ambient temperature, condensing pressure, and first evaporating pressure, calculate the flash evaporator makeup gas ratio and the economizer makeup gas ratio; wherein, the flash evaporator makeup gas ratio satisfies the following formula:

[0125] In the formula, The proportion of gas supplied to the flash evaporator.

[0126] The fuel injection ratio of the economizer must satisfy the following formula:

[0127] In the formula, The proportion of gas supplied to the economizer.

[0128] Basic boundary hard constraints must satisfy Its physical significance lies in the fact that the lower the ambient temperature and the higher the compression ratio, the higher the proportion of deep air injection in the economizer (approaching a 1:1 equilibrium ratio under normal operating conditions).

[0129] Among them, the following must be met under extremely cold heating conditions. This enhances the deep subcooling gas replenishment effect, achieving a maximum deep gas replenishment ratio of 2:8.

[0130] The technical solution provided in this invention addresses the dual-source, layered structure of the system, which consists of "low-pressure gas injection for the flash evaporator + high-pressure gas injection for the economizer," by establishing a dual-variable coupled matching model to achieve stepless continuous adjustment. Specifically, through a dual-source gas injection matching algorithm coupled with ambient temperature and compression ratio, continuous stepless adjustment of the gas injection for both the flash evaporator and the economizer is achieved, resulting in a significant layered gradient enthalpy enhancement effect.

[0131] Optionally, the temperature and pressure parameters also include the compressor discharge temperature; after S130, they also include:

[0132] When satisfied At the same time, increase the proportion of gas supplementation for the economizer; among which, The compressor discharge temperature; when it meets the following conditions At that time, the unit operating frequency decreases at a slope of 0.5 Hz / ℃; when the condition is met... At that time, the shutdown protection is triggered.

[0133] Specifically, when the following conditions are met When (over-temperature warning range, no frequency reduction required), the deep air injection ratio of the economizer needs to be increased according to the following formula to quickly reduce the final compression temperature:

[0134] ; The corrected fuel injection ratio for the economizer. This is the corrected flash evaporator gas supply ratio.

[0135] When satisfied At that time, the unit's operating frequency decreased at a slope of 0.5 Hz / ℃, and when the compressor's discharge temperature... Reduce temperature to 98°C to exit frequency limiting; when the following conditions are met... The shutdown protection mechanism has been triggered.

[0136] Note: Corrected fuel injection ratio for economizers If the limit is exceeded as specified in S130a, then saturation is performed based on the upper limit value to ensure the corrected flash evaporator make-up gas ratio. It is not a negative value.

[0137] The technical solution provided by the embodiments of the present invention ensures that the correction of the compressor exhaust temperature does not result in a loss of heating capacity under the premise of safety.

[0138] See Figure 2 The system includes a compressor, a four-way valve, a solenoid valve, a plate heat exchanger, and a buffer, as well as a first expansion valve, a flash evaporator, an auxiliary valve, an economizer, a second expansion valve, and a finned heat exchanger.

[0139] The first expansion valve is located between the flash steam and the plate heat exchanger; the flash steam is connected to the economizer; the economizer is connected to the buffer and the auxiliary valve respectively; the auxiliary valve is connected to the second expansion valve; the second expansion valve is also connected to the finned heat exchanger; the flash steam is also connected to the solenoid valve; the solenoid valve is also connected to the buffer. The compressor, the four-way valve, and the plate heat exchanger are connected in sequence; the finned heat exchanger is also connected to the four-way valve; the buffer is also connected to the compressor.

[0140] The refrigerant circulation path is as follows: the compressor discharge port is connected to the plate heat exchanger inlet via a four-way valve; the plate heat exchanger outlet is connected to the inlet of the first expansion valve EXV1; the outlet of the first expansion valve EXV1 is connected to the flash evaporator inlet; the first outlet at the top of the flash evaporator enters the buffer via a solenoid valve; the second outlet at the bottom of the flash evaporator enters the economizer main circuit inlet; the economizer main circuit outlet is connected to the second expansion valve EXV2; the second expansion valve EXV2 is connected to the finned heat exchanger; and then returns to the four-way valve to enter the compressor suction port; the economizer auxiliary circuit outlet connects to the buffer and merges with the refrigerant at the top of the flash evaporator to increase the compressor enthalpy inlet.

[0141] The dual-source gas injection enthalpy-increasing heat pump system provided in this embodiment of the invention is used to implement the control method of the dual-source gas injection enthalpy-increasing heat pump system provided in any embodiment of the invention, and has the corresponding beneficial effects of the method.

[0142] Figure 3 A control device for a dual-source injection jet enthalpy-enhancing heat pump system provided in an embodiment of the present invention includes a data acquisition module 210, a calculation module 220, and a control module 230.

[0143] The acquisition module 210 is used to acquire system temperature and pressure parameters based on a preset cycle. The temperature and pressure parameters include condensation pressure and first evaporation pressure.

[0144] The calculation module 220 is used to calculate the total system pressure drop based on the condensing pressure and the first evaporating pressure, and to calculate the target pressure drop of the first expansion valve, the target pressure drop of the auxiliary valve, and the target pressure drop of the second expansion valve, as well as the target pressure of the flash evaporator, based on the total system pressure drop, the condensing pressure, and the first evaporating pressure.

[0145] The control module 230 is used to calculate the target opening degree of the first expansion valve, the auxiliary valve and the second expansion valve according to the target pressure of the flash evaporator, the target pressure drop of the auxiliary valve and the target pressure drop of the second expansion valve, using an incremental PID control algorithm, so as to control the first expansion valve, the auxiliary valve and the second expansion valve to operate according to their respective target opening degrees.

[0146] The control device for a dual-source gas-injection enthalpy-enhancing heat pump system provided in this embodiment of the invention can execute the control method for a dual-source gas-injection enthalpy-enhancing heat pump system provided in any embodiment of the invention, and has the corresponding functional modules and beneficial effects of the method.

[0147] Figure 4 This is a schematic diagram of the electronic device used in a control method for a dual-source injection jet enthalpy-enhancing heat pump system provided in an embodiment of the present invention. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workbenches, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices (e.g., helmets, glasses, watches, etc.), and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the invention described and / or claimed herein.

[0148] like Figure 4 As shown, the electronic device 10 includes at least one processor 11 and a memory, such as a read-only memory (ROM) 12 and a random access memory (RAM) 13, communicatively connected to the at least one processor 11. The memory stores computer programs executable by the at least one processor. The processor 11 can perform various appropriate actions and processes based on the computer program stored in the ROM 12 or loaded into the RAM 13 from storage unit 18. The RAM 13 can also store various programs and data required for the operation of the electronic device 10. The processor 11, the ROM 12, and the RAM 13 are interconnected via a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0149] Multiple components in electronic device 10 are connected to input / output I / O interface 15, including: input unit 16, such as keyboard, mouse, etc.; output unit 17, such as various types of monitors, speakers, etc.; storage unit 18, such as disk, optical disk, etc.; and communication unit 19, such as network card, modem, wireless transceiver, etc. Communication unit 19 allows electronic device 10 to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0150] Processor 11 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, digital signal processors (DSPs), and any suitable processor, controller, microcontroller, etc. Processor 11 performs the various methods and processes described above, such as a control method for a dual-source injection jet enthalpy-enhancing heat pump system.

[0151] In some embodiments, a control method for a dual-source injection jet enthalpy-enhancing heat pump system can be implemented as a computer program tangibly contained in a computer-readable storage medium, such as storage unit 18. In some embodiments, part or all of the computer program can be loaded and / or installed on electronic device 10 via read-only memory ROM 12 and / or communication unit 19. When the computer program is loaded into random access memory RAM 13 and executed by processor 11, one or more steps of the control method for a dual-source injection jet enthalpy-enhancing heat pump system described above can be performed. Alternatively, in other embodiments, processor 11 can be configured in any other suitable manner to perform a control method for a dual-source injection jet enthalpy-enhancing heat pump system.

[0152] Various embodiments of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SoCs), payload-programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transferring data and instructions to the storage system, the at least one input device, and the at least one output device.

[0153] Computer programs used to implement the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that when executed by the processor, the computer programs cause the functions / operations specified in the flowcharts and / or block diagrams to be performed. The computer programs may be executed entirely on a machine, partially on a machine, or as a standalone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0154] In the context of this invention, a computer-readable storage medium can be a tangible medium that may contain or store a computer program for use by or in conjunction with an instruction execution system, apparatus, or device. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0155] To provide interaction with a user, the systems and techniques described herein can be implemented on an electronic device having: a display device for displaying information to a user; and a keyboard and pointing device through which the user provides input to the electronic device. Other types of devices can also be used to provide interaction with a user; for example, feedback provided to the user can be any form of sensory feedback; and input from the user can be received in any form.

[0156] The systems and technologies described herein can be implemented in computing systems that include backend components, middleware components, or frontend components (e.g., a user computer with a graphical user interface or web browser through which a user can interact with implementations of the systems and technologies described herein), or any combination of such backend, middleware, or frontend components. The components of the system can be interconnected via digital data communication of any form or medium. Examples of communication networks include local area networks (LANs), wide area networks (WANs), blockchain networks, and the Internet.

[0157] A computing system can include clients and servers. Clients and servers are generally located far apart and typically interact through communication networks. The client-server relationship is created by computer programs running on the respective computers and having a client-server relationship with each other. The server can be a cloud server, also known as a cloud computing server or cloud host, which is a hosting product within the cloud computing service system to address the shortcomings of traditional physical hosts and VPS services, such as high management difficulty and weak business scalability.

[0158] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0159] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A control method for a dual-source injection-induced enthalpy-enhancing heat pump system, characterized in that, The system includes a first expansion valve, a flash evaporator, an auxiliary valve, an economizer, a second expansion valve, and a finned heat exchanger; the method includes: Based on the preset periodic acquisition of system temperature and pressure parameters, the temperature and pressure parameters include condensation pressure and first evaporation pressure; Based on the condensing pressure and the first evaporating pressure, calculate the total system pressure drop, and based on the total system pressure drop, the condensing pressure and the first evaporating pressure, calculate the target pressure drop of the first expansion valve, the target pressure drop of the auxiliary valve and the target pressure drop of the second expansion valve, as well as the target pressure of the flash evaporator; Based on the target pressure of the flash evaporator, the target pressure drop of the auxiliary valve, and the target pressure drop of the second expansion valve, an incremental PID control algorithm is used to calculate the target opening degree of the first expansion valve, the auxiliary valve, and the second expansion valve, so as to control the first expansion valve, the auxiliary valve, and the second expansion valve to operate according to their respective target opening degrees.

2. The method according to claim 1, characterized in that, Based on the condensing pressure and the first evaporating pressure, calculate the total system pressure drop, and based on the total system pressure drop, the condensing pressure, and the first evaporating pressure, calculate the target pressure drop of the first expansion valve, the target pressure drop of the auxiliary valve, and the target pressure drop of the second expansion valve, as well as the flash evaporator target pressure, including: Calculate the difference between the condensing pressure and the first evaporating pressure, and use the absolute value of the difference as the total pressure drop of the system; Calculate the target pressure drop of the first expansion valve and the target pressure drop of the auxiliary valve based on the total system pressure drop, the condensing pressure, and the first evaporating pressure. Calculate the target pressure drop of the second expansion valve based on the total system pressure drop, the target pressure drop of the first expansion valve, and the target pressure drop of the auxiliary valve. Calculate the target pressure of the flash evaporator based on the target pressure drop of the first expansion valve and the condensing pressure.

3. The method according to claim 2, characterized in that, The total system voltage drop is calculated using the following formula: In the formula, For the total system voltage drop, For condensation pressure, This is the first evaporation pressure; The target pressure drop of the first expansion valve is calculated using the following formula: In the formula, The target pressure drop for the first expansion valve; The target pressure drop of the auxiliary valve is calculated using the following formula: In the formula, For auxiliary valve target pressure drop; The target pressure drop of the second expansion valve is calculated using the following formula: In the formula, The target pressure drop for the second expansion valve; The target pressure of the flash evaporator is calculated using the following formula: In the formula, The target pressure for the flash evaporator.

4. The method according to claim 1, characterized in that, The temperature and pressure parameters also include the second evaporation pressure, compressor suction temperature, economizer outlet liquid phase temperature, economizer outlet subcooling, and finned heat exchanger suction superheat. Based on the target pressure of the flash evaporator, the target pressure drop of the auxiliary valve, and the target pressure drop of the second expansion valve, an incremental PID control algorithm is used to calculate the target opening degree of the first expansion valve, the auxiliary valve, and the second expansion valve, including: The target opening of the first expansion valve is calculated using the following formula: In the formula, for The target opening degree of the first expansion valve at time t, and the constraint range of the target opening degree of the first expansion valve are: , for The target opening degree of the first expansion valve at any given time. This represents the increment of the opening of the first expansion valve; where, In the formula, , and These are the proportional, integral, and derivative coefficients of the first expansion valve, respectively, and their values ​​are... , For the first expansion valve The first deviation in time, For the first expansion valve The first deviation in time, For the first expansion valve The first deviation in time; In the formula, The target pressure for the flash evaporator, for The second evaporation pressure at that moment; The target opening degree of the auxiliary valve is calculated using the following formula: In the formula, for The target opening degree of the auxiliary valve at any given time, and the constraint range of the target opening degree of the auxiliary valve is: , for The target opening degree of the auxiliary valve at any given time. For the auxiliary valve opening increment; among which, In the formula, , These are the proportional and integral coefficients of the auxiliary valve, with values ​​of [values ​​to be filled in]. , Auxiliary valve The second deviation in time, Auxiliary valve The second deviation in time; In the formula, The target value for the supercooling of the export of the economizer. for The current economic export overcooling; In the formula, This is the saturation temperature corresponding to the second evaporation pressure. The outlet liquid phase temperature of the economizer; The target opening degree of the second expansion valve is calculated using the following formula: In the formula, for The target opening degree of the second expansion valve at time t, the constraint range of the target opening degree of the second expansion valve is t. , for The target opening degree of the second expansion valve at any given time. This represents the increment of the second expansion valve opening; where, In the formula, , and These are the proportional, integral, and derivative coefficients of the second expansion valve, with values ​​of [values ​​to be filled in]. , For the second expansion valve The third deviation in time, For the second expansion valve The third deviation in time, For the second expansion valve The third deviation in time; In the formula, The target value for the intake superheat of the finned heat exchanger. for The constant temperature of the finned heat exchanger intake superheat; In the formula, This refers to the compressor suction temperature. This is the saturation temperature corresponding to the first evaporation pressure.

5. The method according to claim 1, characterized in that, The temperature and pressure parameters also include ambient temperature; before calculating the total system pressure drop based on the condensing pressure and the first evaporating pressure, the following is also included: The heating conditions are determined based on the ambient temperature, condensing pressure, and first evaporating pressure.

6. The method according to claim 5, characterized in that, The heating operating conditions are determined based on ambient temperature, condensing pressure, and first evaporating pressure, including: When satisfied At that time, it was determined to be an extremely cold heating condition; among them, Ambient temperature; When satisfied At that time, it was determined to be a normal temperature heating condition; When satisfied When the extreme cold heating condition is reached, the control boundary shall be followed. When satisfied If the condition is not met, the heating mode determination will be exited.

7. The method according to claim 6, characterized in that, Before calculating the target opening degree of the first expansion valve, auxiliary valve, and second expansion valve respectively using an incremental PID control algorithm based on the target pressure of the flash evaporator, the target pressure drop of the auxiliary valve, and the target pressure drop of the second expansion valve, the following steps are included: Based on the ambient temperature, condensing pressure, and first evaporating pressure, calculate the flash evaporator makeup gas ratio and the economizer makeup gas ratio; wherein, the flash evaporator makeup gas ratio satisfies the following formula: In the formula, The proportion of gas supplied to the flash evaporator; The fuel injection ratio of the economizer must satisfy the following formula: In the formula, The proportion of fuel added to the economizer; Basic boundary hard constraints must satisfy Under extremely cold heating conditions, it must meet the following requirements. .

8. The method according to claim 7, characterized in that, The temperature and pressure parameters also include the compressor discharge temperature; after calculating the target opening degree of the first expansion valve, the auxiliary valve, and the second expansion valve using an incremental PID control algorithm based on the flash evaporator target pressure, the auxiliary valve target pressure drop, and the second expansion valve target pressure drop, the parameters also include: When satisfied At the same time, increase the proportion of gas supplementation for the economizer; among which, This refers to the compressor discharge temperature. When satisfied At that time, the unit's operating frequency decreases at a slope of 0.5 Hz / ℃; When satisfied At that time, the shutdown protection is triggered.

9. The method according to claim 4, characterized in that, Based on the target pressure of the flash evaporator, the target pressure drop of the auxiliary valve, and the target pressure drop of the second expansion valve, an incremental PID control algorithm is used to calculate the target opening degree of the first expansion valve, the auxiliary valve, and the second expansion valve, including: The formula is applied based on the first evaporation pressure and the second evaporation pressure. Calculate the actual pressure drop of the auxiliary valve; where, The actual pressure drop of the auxiliary valve; When the formula is satisfied At that time, the integral term limit value of the auxiliary valve PI control algorithm is triggered by... Dynamic compression to ; Calculate the actual pressure drop of the second expansion valve based on the second evaporation pressure and the preset saturation pressure; When the deviation between the actual pressure drop of the second expansion valve and the target pressure drop of the second expansion valve exceeds ±18% for more than 30 seconds, an alarm is triggered and the second expansion valve is switched to the preset safe opening degree.

10. A dual-source injection-induced enthalpy-increasing heat pump system, comprising a compressor, a four-way valve, a solenoid valve, a plate heat exchanger, and a buffer, characterized in that, It also includes a first expansion valve, a flash evaporator, an auxiliary valve, an economizer, a second expansion valve, and a finned heat exchanger.

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