CN115654700A

CN115654700A - Air injection enthalpy increasing control method and device of air conditioner and air conditioner

Info

Publication number: CN115654700A
Application number: CN202211246021.2A
Authority: CN
Inventors: 王穗; 陈体宁; 张稳; 刘合心
Original assignee: Ningbo Aux Electric Co Ltd
Current assignee: Ningbo Aux Electric Co Ltd
Priority date: 2022-10-12
Filing date: 2022-10-12
Publication date: 2023-01-31

Abstract

The invention discloses an enhanced vapor injection control method and device of an air conditioner and the air conditioner, and relates to the technical field of air conditioners, wherein the method comprises the following steps: step S202, detecting exhaust superheat degree, main path supercooling degree, main path superheat degree and auxiliary path superheat degree under the condition of operating in an enhanced vapor injection heating mode; step S204, correcting the main road target superheat degree and the auxiliary road target superheat degree based on the exhaust superheat degree and the main road supercooling degree so as to enable the main road target superheat degree and the auxiliary road target superheat degree to enter a preset reasonable superheat degree range; step S206, controlling the opening degree of the main-path electronic expansion valve according to the main-path superheat degree and the corrected main-path target superheat degree; step S208, controlling the opening degree of the auxiliary road electronic expansion valve according to the auxiliary road superheat degree and the corrected auxiliary road target superheat degree; step S202 to step S208 are repeatedly executed until a steady state is reached. The invention ensures that the flow distribution of the refrigerant in the air conditioning unit is more reasonable, and improves the operation reliability of the air conditioner.

Description

Air injection enthalpy increasing control method and device of air conditioner and air conditioner

Technical Field

The invention relates to the technical field of air conditioners, in particular to an enhanced vapor injection control method and device of an air conditioner and the air conditioner.

Background

At present, a heat pump unit air conditioner generally adopts enhanced vapor injection to improve the low-temperature heating performance of the air conditioner, the displacement of a compressor is improved through medium-pressure air supplement, the capacity of the unit is improved, and in the enhanced vapor injection unit, the capacity of an auxiliary path can directly influence the capacity, the energy efficiency and the reliability of the unit.

The conventional enhanced vapor injection technology generally controls the air supplement amount by controlling an auxiliary electronic expansion valve, and adjusts the opening of the auxiliary electronic expansion valve according to the superheat degree of an auxiliary refrigerant, but in the actual use scene of the air conditioning unit, the indoor side and outdoor side ambient temperature ranges are wide, the starting capacity and the running state of an indoor unit are different, and the opening of the auxiliary electronic expansion valve is controlled by using the superheat degree of a fixed auxiliary refrigerant, so that certain refrigerant flow control deviation is easily caused, the problems of noise and the like of an air conditioner are caused, and the running reliability of the air conditioner is reduced.

Disclosure of Invention

In order to solve the problems, the invention provides an enhanced vapor injection control method and device for an air conditioner and the air conditioner, which can cooperatively control a main electronic expansion valve and an auxiliary electronic expansion valve, so that the refrigerant flow distribution in an air conditioning unit is more reasonable, the noise problem is avoided, and the operation reliability of the air conditioner is improved.

According to an embodiment of the present invention, in one aspect, a method for controlling enhanced vapor injection of an air conditioner is provided, including: step S202, detecting exhaust superheat degree, main path supercooling degree, main path superheat degree and auxiliary path superheat degree under the condition of operating in an enhanced vapor injection heating mode; the main path supercooling degree is the difference between the saturation temperature corresponding to the exhaust pressure and the outlet temperature of the main path of the economizer, the main path superheating degree is the difference between the outlet temperature of the heat exchanger and the temperature in the pipe, and the auxiliary path superheating degree is the difference between the outlet temperature of the auxiliary path of the economizer and the inlet temperature; step S204, correcting the main road target superheat degree and the auxiliary road target superheat degree based on the exhaust superheat degree and the main road supercooling degree so as to enable the main road target superheat degree and the auxiliary road target superheat degree to enter a preset reasonable superheat degree range; the exhaust superheat degree and the main path supercooling degree correspond to a preset main path target superheat degree correction value and a preset auxiliary path target superheat degree correction value; step S206, controlling the opening of the main electronic expansion valve according to the main superheat degree and the corrected main target superheat degree; step S208, controlling the opening degree of the auxiliary road electronic expansion valve according to the auxiliary road superheat degree and the corrected auxiliary road target superheat degree; step S202 to step S208 are repeatedly executed until a steady state is reached.

By adopting the technical scheme, when the air conditioner is in an enhanced vapor injection heating mode, the main path target superheat degree and the auxiliary path target superheat degree are corrected according to the exhaust superheat degree and the main path subcooling degree, self-adaptive control over the main path target superheat degree and the auxiliary path target superheat degree can be achieved, and then the main path electronic expansion valve and the auxiliary path electronic expansion valve can be cooperatively controlled, so that the refrigerant flow distribution in the air conditioning unit is more reasonable, the noise problem is avoided, and the operation reliability of the air conditioner is improved.

Preferably, the step of correcting the main route target superheat degree and the sub route target superheat degree based on the exhaust superheat degree and the main route subcooling degree includes: when the exhaust superheat degree is smaller than a first preset threshold value, controlling the main road target superheat degree to increase a first numerical value, and controlling the auxiliary road superheat degree to increase a second numerical value; when the exhaust superheat degree is larger than or equal to the first preset threshold and smaller than or equal to the second preset threshold, controlling the main road target superheat degree to be unchanged, and correcting the auxiliary road target superheat degree according to the main road superheat degree; and when the exhaust superheat degree is larger than the second preset threshold value, controlling the main road target superheat degree to reduce a third numerical value, and correcting the auxiliary road target subcooling degree according to the main road subcooling degree.

By adopting the technical scheme, the main road target superheat degree and the auxiliary road target superheat degree are corrected according to the value range of the exhaust superheat degree, the exhaust superheat degree can be corrected, self-adaptive control of the target superheat degree is used for replacing fixed superheat degree control, the exhaust superheat degree is guaranteed to be in a reasonable range, the problem of two-phase flow noise is avoided, and the use experience of a user is improved.

Preferably, the step of correcting the auxiliary road target superheat degree according to the main road supercooling degree includes: under the condition that the exhaust superheat degree is larger than or equal to the first preset threshold and smaller than or equal to the second preset threshold, if the main road supercooling degree is smaller than a third preset threshold, controlling the auxiliary road target superheat degree to be reduced by a fourth value, and if the main road supercooling degree is larger than or equal to the third preset threshold, controlling the auxiliary road target superheat degree to be kept unchanged; under the condition that the exhaust superheat degree is larger than the second preset threshold, if the main path supercooling degree is smaller than or equal to a fourth preset threshold, controlling the auxiliary path target superheat degree to be reduced by a fifth value, and if the main path supercooling degree is larger than the fourth preset threshold, controlling the auxiliary path target superheat degree to be kept unchanged; wherein the fourth preset threshold is greater than the third preset threshold.

By adopting the technical scheme, the auxiliary road target superheat degree is adjusted according to the value ranges of the exhaust superheat degree and the main road supercooling degree, the considered integral operation condition of the air conditioning unit is realized, the refrigerant flow adjustment in the unit is adjusted by the regional superheat degrees of the main road and the auxiliary road, and is converted into the integral adjustment of the exhaust superheat degree and the main road supercooling degree, the air conditioning unit is in a better operation state, the control of the main road supercooling degree is considered on the premise of ensuring the main road superheat degree, the auxiliary road superheat degree and the exhaust superheat degree, the flow distribution proportion is more reasonable, and the operation reliability of the air conditioner is ensured.

Preferably, the step of controlling the opening degree of the main path electronic expansion valve according to the main path superheat degree and the corrected main path target superheat degree includes: calculating the difference value between the main path superheat degree and the corrected main path target superheat degree, and recording the difference value as a first difference value; controlling the opening change value of the main electronic expansion valve to be delta PM = delta ASH and K1; wherein Δ ASH is the first difference, K1 is a main path electronic expansion valve adjustment coefficient, and K1 is greater than 0.

By adopting the technical scheme, the opening degree change value of the main-path electronic expansion valve is in positive correlation with the first difference value, the main-path refrigerant flow can be increased when the main-path superheat degree is greater than the main-path target superheat degree, the main-path superheat degree is reduced, the main-path refrigerant flow can be reduced when the main-path superheat degree is less than the main-path target superheat degree, the main-path superheat degree can approach to or equal to the main-path target superheat degree all the time, and the main-path superheat degree is guaranteed to be in a reasonable range all the time.

Preferably, the step of controlling the opening degree of the sub-passage electronic expansion valve based on the degree of superheat of the sub-passage and the corrected target degree of superheat of the sub-passage includes: calculating the difference value between the auxiliary road superheat degree and the corrected auxiliary road target superheat degree, and recording the difference value as a second difference value; controlling the opening change value of the auxiliary electronic expansion valve to be delta PE = delta ESH × K2; wherein, Δ ESH is the second difference, K2 is the adjustment coefficient of the auxiliary electronic expansion valve, and K2 is more than 0.

By adopting the technical scheme, the opening degree change value of the auxiliary electronic expansion valve is positively correlated with the second difference value, the auxiliary refrigerant flow can be increased when the auxiliary superheat degree is greater than the auxiliary target superheat degree, the auxiliary superheat degree is reduced, the auxiliary refrigerant flow can be reduced when the auxiliary superheat degree is less than the auxiliary target superheat degree, the auxiliary superheat degree is increased, the auxiliary superheat degree can be always close to or equal to the auxiliary target superheat degree, the auxiliary superheat degree is guaranteed to be always in a reasonable range, and the control accuracy of the auxiliary electronic expansion valve is improved.

Preferably, the enhanced vapor injection control method of the air conditioner further includes: when the steady state is reached, judging whether the condition that the supercooling degree is insufficient and the auxiliary electronic expansion valve does not have an adjusting space exists at present, if so, controlling the main electronic expansion valve to periodically reduce the preset opening degree to supplement the supercooling degree until the preset supercooling degree supplement exit condition is met, and exiting the supplementary supercooling degree control; the preset supercooling degree supplement exit condition comprises any one of the following conditions: the exhaust temperature is higher than the preset temperature; the supercooling degree of the main path is greater than or equal to the third preset threshold value; the main path superheat degree is larger than or equal to the maximum value of the preset range; and the main-path electronic expansion valve reaches the minimum opening degree.

By adopting the technical scheme, when the supercooling degree of the air conditioner is insufficient and the auxiliary expansion valve has no adjusting space, the main electronic expansion valve is controlled to be turned off to supplement the supercooling degree, so that the supercooling degree of the main circuit is improved, the noise of the air conditioning unit is avoided, the supplement control of the condition exceeding the control range is realized, and the operation reliability of the air conditioner is improved.

Preferably, the step of determining whether the supercooling degree is insufficient and the auxiliary electronic expansion valve does not have a regulation space includes: judging whether the following first condition to fourth condition are met at the same time, if so, determining that the condition that the supercooling degree is insufficient and the auxiliary electronic expansion valve does not have an adjusting space exists at present; wherein the first to fourth conditions include: a first condition that the exhaust superheat degree is greater than or equal to the first preset threshold value; under a second condition, the supercooling degree of the main path is smaller than the third preset threshold value; a third condition that the main path superheat degree is within a preset range; and under the fourth condition, the auxiliary road superheat degree reaches the minimum value in a reasonable superheat degree range, or the auxiliary road electronic expansion valve reaches the maximum opening degree.

By adopting the technical scheme, whether the air conditioner has the condition of insufficient supercooling degree is judged according to the exhaust superheat degree, the main path supercooling degree and the main path superheat degree, whether the auxiliary path electronic expansion valve has no adjusting space is judged according to the auxiliary path superheat degree or the auxiliary path electronic expansion valve, whether the condition of insufficient supercooling degree exists at present and the condition of no adjusting space exists in the auxiliary path electronic expansion valve can be accurately judged, and noise of the air conditioner caused by insufficient supercooling degree is avoided.

Preferably, the enhanced vapor injection control method of the air conditioner further includes: and when the stable state is reached, if the liquid impact risk exists and no adjusting space exists between the main-path electronic expansion valve and the auxiliary-path electronic expansion valve, the enhanced vapor injection heating mode is controlled to exit.

By adopting the technical scheme, when the air conditioner has liquid impact risk and the main-path electronic expansion valve and the auxiliary-path electronic expansion valve do not have adjusting space, the jet enthalpy-increasing heating mode is controlled to exit in time, liquid impact can be effectively prevented, and the operation reliability of the air conditioner is ensured.

Preferably, the enhanced vapor injection control method of an air conditioner further comprises: when the following conditions from one to five are met, determining that the liquid impact risk exists and no adjusting space exists between the main-path electronic expansion valve and the auxiliary-path electronic expansion valve; wherein the first to fifth conditions include: the exhaust superheat degree is smaller than the first preset threshold value under the condition one; secondly, the target superheat degree of the main path reaches the maximum value of a preset superheat degree range of the main path; thirdly, the target degree of superheat of the auxiliary road reaches the maximum value of a preset degree of superheat range of the auxiliary road; fourthly, the main-path electronic expansion valve reaches the minimum opening degree, or the main-path superheat degree reaches the maximum value of the main-path preset superheat degree range; and fifthly, the auxiliary circuit electronic expansion valve reaches the minimum opening degree, or the auxiliary circuit superheat degree reaches the maximum value of the auxiliary circuit preset superheat degree range.

By adopting the technical scheme, whether liquid impact risks exist or not is judged according to the exhaust superheat degree, the main path target superheat degree, the auxiliary path target superheat degree, the main path electronic expansion valve and the auxiliary path electronic expansion valve, whether liquid impact risks exist or not can be judged in time, liquid impact is avoided, and the stability of air injection enthalpy gain control of the air conditioner is improved.

According to an embodiment of the present invention, in another aspect, there is provided an enhanced vapor injection control apparatus for an air conditioner, including: the detection module is used for detecting the exhaust superheat degree, the main path supercooling degree, the main path superheat degree and the auxiliary path superheat degree under the condition of operating in the enhanced vapor injection heating mode; the main path supercooling degree is the difference value between the saturation temperature corresponding to the exhaust pressure and the outlet temperature of the main path of the economizer, the main path superheat degree is the difference value between the outlet temperature and the inlet temperature of the heat exchanger, and the auxiliary path superheat degree is the difference value between the outlet temperature and the inlet temperature of the auxiliary path of the economizer; the correction module is used for correcting the main road target superheat degree and the auxiliary road target superheat degree based on the exhaust superheat degree and the main road supercooling degree so as to enable the main road target superheat degree and the auxiliary road target superheat degree to enter a preset reasonable superheat degree range; the exhaust superheat degree and the main path supercooling degree correspond to a preset main path target superheat degree correction value and a preset auxiliary path target superheat degree correction value; the first control module is used for controlling the opening degree of the main road electronic expansion valve according to the main road superheat degree and the corrected main road target superheat degree; the second control module is used for controlling the opening of the auxiliary road electronic expansion valve according to the auxiliary road superheat degree and the corrected auxiliary road target superheat degree; and the circulating execution module is used for triggering the detection module to start running after the second control module finishes executing until a stable state is reached.

According to an embodiment of the present invention, in another aspect, an air conditioner is provided, which includes a computer readable storage medium storing a computer program and a processor, wherein the computer program is read by the processor and when executed, implements the method according to any one of the first aspect.

The invention has the following beneficial effects: when the air conditioner is in an enhanced vapor injection heating mode, the main path target superheat degree and the auxiliary path target superheat degree are corrected according to the exhaust superheat degree and the main path subcooling degree, self-adaptive control over the main path target superheat degree and the auxiliary path target superheat degree can be achieved, and then the main path electronic expansion valve and the auxiliary path electronic expansion valve can be cooperatively controlled, so that the refrigerant flow distribution in the air conditioning unit is more reasonable, the noise problem is avoided, and the running reliability of the air conditioner is improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below. It should be apparent that the drawings in the following description are merely exemplary, and that other embodiments can be derived from the drawings provided by those of ordinary skill in the art without inventive effort.

The structures, ratios, sizes, and the like shown in the present specification are only used for matching with the contents disclosed in the specification, so as to be understood and read by those skilled in the art, and are not used to limit the conditions that the present invention can be implemented, so that the present invention has no technical significance, and any structural modifications, changes in the ratio relationship, or adjustments of the sizes, without affecting the effects and the achievable by the present invention, should still fall within the range that the technical contents disclosed in the present invention can cover.

Fig. 1 is a schematic view illustrating an outdoor unit for an air conditioner according to the present invention;

FIG. 2 is a flow chart of a method for controlling enhanced vapor injection of an air conditioner according to the present invention;

fig. 3 is a schematic structural diagram of an enhanced vapor injection control device of an air conditioner according to the present invention.

Detailed Description

The present invention is described in terms of particular embodiments, other advantages and features of the invention will become apparent to those skilled in the art from the following disclosure, and it is to be understood that the described embodiments are merely exemplary of the invention and that it is not intended to limit the invention to the particular embodiments disclosed. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.

In this embodiment, referring to the schematic structural diagram of the outdoor unit of the air conditioner shown in fig. 1, the outdoor unit includes a compressor COM, an outdoor unit heat exchanger CON, a main electronic expansion valve EXVM, an auxiliary electronic expansion valve EXVI, an auxiliary enthalpy spray solenoid valve SVI, an economizer ECR, and the like.

As shown in fig. 1, a pressure sensor PD and a temperature sensor TD are respectively disposed on a discharge pipe of the compressor COM for detecting a discharge pressure and a discharge temperature. The economizer ECR auxiliary road comprises an economizer ECR main road and is characterized in that a temperature sensor TI, an auxiliary road electronic expansion valve EXVI and an auxiliary road enthalpy spraying electromagnetic valve SVI are sequentially arranged on an inlet pipeline of the economizer ECR auxiliary road, a temperature sensor TO is arranged on an outlet pipeline of the economizer ECR auxiliary road, a temperature sensor TM is arranged on an outlet pipeline of the economizer ECR main road, the temperature sensor TM is used for detecting the outlet temperature of the economizer main road, the temperature sensor TI is used for detecting the inlet temperature of the economizer auxiliary road, and the temperature sensor TO is used for detecting the outlet temperature of the economizer auxiliary road.

In the heating mode, a high-temperature and high-pressure gaseous refrigerant enters an indoor unit, and after heat is released by the indoor unit, the gaseous refrigerant is changed into a high-pressure medium-temperature liquid refrigerant and returns to the outdoor unit; in a common heating mode, an auxiliary path enthalpy injection solenoid valve SVI is closed, refrigerant entering an outdoor unit from an indoor unit passes through an economizer ECR, is throttled by a main path electronic expansion valve EXVM and enters an outdoor unit heat exchanger CON, and the refrigerant is changed into low-temperature low-pressure gaseous refrigerant after evaporation and heat exchange, and returns to a return air port of a compressor through a four-way valve and a gas-liquid separator. TC is the temperature in the outer heat exchanger tube, where the refrigerant is not completely evaporated, and is a two-phase refrigerant, TA is the outer heat exchanger outlet temperature, where the refrigerant is completely evaporated, and is a gaseous refrigerant, and the heat exchanger superheat ASH = TA-TC, which may also be referred to as the main path superheat.

In the enhanced vapor injection heating mode, the auxiliary path enthalpy injection solenoid valve SVI is opened, the refrigerant is divided into two parts at the position of a three-way joint after passing through the economizer, and the main path returns to the COM suction port of the compressor through the outdoor unit heat exchanger CON, the four-way valve and the gas-liquid separator as indicated by the arrow in figure 1; as shown in fig. 1, the dashed line is an auxiliary path, after passing through an auxiliary enthalpy injection solenoid valve SVI, the auxiliary refrigerant is throttled by an auxiliary electronic expansion valve EXVI to become a low-temperature low-pressure two-phase refrigerant, at this time, the temperature of the auxiliary refrigerant is far lower than that of the main refrigerant, and after the two refrigerants exchange heat in the economizer ECR, the auxiliary refrigerant becomes a gaseous refrigerant and returns to the compressor air supplement port (the temperature of the main refrigerant outlet is reduced). TI is the temperature of two-phase refrigerant after throttling of an auxiliary road (namely the inlet temperature of an auxiliary road of the economizer), TO is the temperature of gaseous refrigerant after heat exchange of the auxiliary road (the outlet temperature of the auxiliary road of the economizer), the degree of superheat of the refrigerant of the auxiliary road (namely the degree of superheat of the auxiliary road) ESH = TO-TI, the temperature of the refrigerant of the main road is obviously higher than that of the refrigerant after throttling of the auxiliary road, the refrigerant of the main road in the economizer releases heat, the refrigerant of the auxiliary road absorbs heat, TM is the temperature of the refrigerant of the main road after heat release (namely the outlet temperature of the main road of the economizer), and when the pressure of the refrigerant of the main road is close TO the exhaust position, the degree of supercooling of the refrigerant of the main road (also called the degree of supercooling of the main road) ESC = TSD-TM, and TSD is the saturation temperature corresponding TO the exhaust pressure.

The present embodiment provides an enhanced vapor injection control method for an air conditioner, which may be applied to the air conditioner provided in the above embodiment, referring to a flow chart of the enhanced vapor injection control method for the air conditioner shown in fig. 2, the method mainly includes the following steps S202 to S208:

step S202: and under the condition of operating in the enhanced vapor injection heating mode, detecting the exhaust superheat degree, the main path supercooling degree, the main path superheat degree and the auxiliary path superheat degree.

When the air conditioner is detected TO be in a heating mode and the auxiliary path enthalpy injection electromagnetic valve SVI is opened, the fact that the air conditioner operates in an enhanced vapor injection heating mode at present is determined, the main path electronic expansion valve EXVM and the auxiliary path electronic expansion valve EXVI operate at set initial opening degrees respectively, the exhaust temperature TD, the exhaust pressure PD, the outlet temperature TM of the main path of the economizer, the outlet temperature TA of the heat exchanger, the temperature TC in the heat exchanger pipe, the outlet temperature TO of the auxiliary path of the economizer and the inlet temperature TI of the auxiliary path of the economizer are detected, and the saturation temperature TSD corresponding TO the exhaust pressure PD is obtained.

And calculating the exhaust superheat DSH = TD-TSD, wherein the main circuit supercooling degree is the difference value between the saturation temperature corresponding to the exhaust pressure and the outlet temperature of the main circuit of the economizer, and the main circuit supercooling degree ESC = TSD-TM is calculated.

The main path superheat degree is the difference value between the outlet temperature of the heat exchanger and the temperature in the pipe, and the auxiliary path superheat degree is the difference value between the outlet temperature and the inlet temperature of the auxiliary path of the economizer. And calculating a main road superheat degree (namely, a heat exchanger superheat degree) ASH = TA-TC, and calculating an auxiliary road superheat degree ESH = TO-TI.

Step S204: and correcting the main path target superheat degree and the auxiliary path target superheat degree based on the exhaust superheat degree and the main path supercooling degree so as to enable the main path target superheat degree and the auxiliary path target superheat degree to enter a preset reasonable superheat degree range.

The exhaust superheat degree and the main path supercooling degree correspond to a preset main path target superheat degree correction value and a preset auxiliary path target superheat degree correction value. When the exhaust superheat degree and the main path supercooling degree are in different interval ranges, different main path target superheat degree correction values and auxiliary path target superheat degree correction values can be correspondingly obtained.

The preset reasonable superheat degree range can comprise a main road superheat degree reasonable range and an auxiliary road superheat degree reasonable range input by a user. In practical application, the main road target superheat degree and the auxiliary road target superheat degree are generally provided with reasonable target superheat degree value ranges, when the target superheat degree is corrected, the corrected target superheat degree needs to be within the reasonable superheat degree range, the main road target superheat degree can reach the main road target superheat degree, the auxiliary road superheat degree can reach the auxiliary road target superheat degree, and the main road superheat degree and the auxiliary road superheat degree can also be within the preset reasonable superheat degree range.

Step S206: and controlling the opening degree of the main path electronic expansion valve according to the main path superheat degree and the corrected main path target superheat degree.

After the main path target superheat degree SASH is corrected, the actual main path superheat degree ASH usually deviates from the corrected main path target superheat degree, and the opening degree of the main path electronic expansion valve is further adjusted according to the magnitude relation between the main path superheat degree and the corrected main path target superheat degree, so that ASH = SASH. When the main path superheat degree is larger than the corrected main path target superheat degree, controlling the opening of the main path electronic expansion valve to be increased so as to increase the main path refrigerant flow and reduce the main path superheat degree, so that the main path superheat degree is gradually close to the corrected main path target superheat degree; and when the main path superheat degree is smaller than the corrected main path target superheat degree, controlling the opening degree of the main path electronic expansion valve to be reduced so as to reduce the main path refrigerant flow and increase the main path superheat degree, so that the main path superheat degree gradually approaches the corrected main path target superheat degree until ASH = SASH.

Step S208: and controlling the opening degree of the auxiliary road electronic expansion valve according to the auxiliary road superheat degree and the corrected auxiliary road target superheat degree.

After the target degree of superheat SESH of the sub-road is corrected, the actual degree of superheat ESH of the sub-road deviates from the corrected target degree of superheat of the sub-road, and the opening degree of the electronic expansion valve of the sub-road is further adjusted according to the magnitude relationship between the degree of superheat of the sub-road and the corrected target degree of superheat of the sub-road, so that ESH = SESH. When the degree of superheat of the auxiliary road is greater than the corrected target degree of superheat of the auxiliary road, controlling the opening of the electronic expansion valve of the auxiliary road to increase the flow of refrigerant of the auxiliary road, reducing the degree of superheat of the auxiliary road, and enabling the degree of superheat of the auxiliary road to be gradually close to the corrected target degree of superheat of the auxiliary road until ESH = SESH; and when the degree of superheat of the auxiliary road is smaller than the corrected target degree of superheat of the auxiliary road, controlling the opening degree of the auxiliary road electronic expansion valve to be reduced, reducing the flow of the auxiliary road refrigerant, and increasing the degree of superheat of the auxiliary road until ESH = SESH.

Step S202 to step S208 are repeatedly executed until a steady state is reached.

After the opening degrees of the main-path electronic expansion valve and the auxiliary-path electronic expansion valve are adjusted, the flow rates of the main-path refrigerant and the auxiliary-path refrigerant are changed, and the superheat degree of the main path and the superheat degree of the auxiliary path are correspondingly changed, so that the exhaust superheat degree, the main-path subcooling degree, the main-path superheat degree and the auxiliary-path superheat degree are changed, after the opening degrees of the main-path electronic expansion valve and the auxiliary-path electronic expansion valve are adjusted, the exhaust superheat degree, the main-path subcooling degree, the main-path superheat degree and the auxiliary-path superheat degree are detected again, the main-path target superheat degree and the auxiliary-path target superheat degree are corrected again, and then continuous circulation adjustment is carried out on the opening degrees of the main-path electronic expansion valve and the auxiliary-path electronic expansion valve until the air conditioner reaches a stable state.

In one embodiment, the steady state includes that the exhaust superheat degree, the main path subcooling degree, the main path superheat degree and the auxiliary path superheat degree reach the control target range, that is, the exhaust superheat degree is in the normal exhaust superheat degree range, the main path subcooling degree is in the normal subcooling degree range, and the main path superheat degree and the auxiliary path superheat degree are in the reasonable superheat degree range; in another embodiment, the steady state may be a condition where the degree of subcooling is insufficient but the opening of the auxiliary electronic expansion valve is not adjustable, or a condition where the degree of superheat of the exhaust gas is too low but there is no adjustment space for both the main electronic expansion valve and the auxiliary electronic expansion valve.

According to the enhanced vapor injection control method of the air conditioner, under the enhanced vapor injection heating mode, the main path target superheat degree and the auxiliary path target superheat degree are corrected according to the exhaust superheat degree and the main path supercooling degree, self-adaptive control over the main path target superheat degree and the auxiliary path target superheat degree can be achieved, and then the main path electronic expansion valve and the auxiliary path electronic expansion valve can be cooperatively controlled, so that the refrigerant flow distribution in the air conditioning unit is more reasonable, the noise problem is avoided, and the operation reliability of the air conditioner is improved.

Referring to the parameter name list shown in table one below, the parameter name corresponding to each parameter is shown in table one.

Table-parameter name list

In one embodiment, to improve the control accuracy of the main-path electronic expansion valve, the embodiment provides a specific implementation manner of controlling the opening degree of the main-path electronic expansion valve according to the main-path superheat degree and the corrected main-path target superheat degree: calculating the difference value of the main path superheat degree and the corrected main path target superheat degree, and recording the difference value as a first difference value; controlling the opening change value of the main electronic expansion valve to be delta PM = delta ASH and K1; wherein, Δ ASH is a first difference value, K1 is a main-path electronic expansion valve adjusting coefficient, and K1 is greater than 0.

When the delta ASH is larger than 0, the delta PM is larger than 0, the opening degree of the main-circuit electronic expansion valve is controlled to be increased by | delta PM |, when the delta ASH is smaller than 0, the delta PM is smaller than 0, and the opening degree of the main-circuit electronic expansion valve is controlled to be decreased by | delta PM |.

The target value of the main road superheat degree ASH is a main road target superheat degree SASH, a first difference value delta ASH = ASH-SASH between the main road superheat degree and the corrected main road target superheat degree (namely the current main road target superheat degree) is calculated, the opening change value of the main road electronic expansion valve is calculated according to the first difference value, the delta PM value is positively correlated with the delta ASH, and the size is influenced by the K1 value. When Δ ASH > 0, the actual main path superheat degree ASH is greater than the main path target superheat degree SASH, the main path refrigerant flow needs to be increased, ASH is reduced (when the heat exchange amount is equal, the refrigerant flow ≠ and the heat exchanger outlet temperature ↓), ASH = SASH, the refrigerant flow is positively correlated with the valve opening, and at this time, the main path electronic expansion valve needs to be increased, that is, Δ PM > 0; similarly, when Δ ASH is less than 0, Δ PM is less than 0, and the opening of the main-path electronic expansion valve should be correspondingly reduced, so as to raise ASH, and make ASH = SASH. In order to ensure the main path flow regulation range, the regulation range of the main path electronic expansion valve can be set as [ EVMMIN, EVMMAX ], the EVMMIN is the minimum opening value, and the EVMMAX is the maximum value. In order to ensure that the main path superheat ASH can be within a reasonable superheat range, the main path target superheat SASH may be set to have a reasonable superheat range [ AMIN, AMAX ].

By making the opening degree change value of the main path electronic expansion valve in positive correlation with the first difference value, the main path refrigerant flow can be increased when the main path superheat degree is greater than the main path target superheat degree, the main path superheat degree is reduced, the main path refrigerant flow can be reduced when the main path superheat degree is less than the main path target superheat degree, the main path superheat degree can be always close to or equal to the main path target superheat degree, and the main path superheat degree is guaranteed to be always in a reasonable range.

In one embodiment, in order to improve the control accuracy of the auxiliary electronic expansion valve, the embodiment provides a specific implementation manner of controlling the opening degree of the auxiliary electronic expansion valve according to the auxiliary superheat degree and the corrected auxiliary target superheat degree: calculating the difference value between the auxiliary road superheat degree and the corrected auxiliary road target superheat degree, and recording the difference value as a second difference value; controlling the opening change value of the auxiliary electronic expansion valve to be delta PE = delta ESH and K2; wherein, the delta ESH is a second difference value, K2 is an adjusting coefficient of the auxiliary electronic expansion valve, and K2 is more than 0.

When the delta ESH is larger than 0, the delta PE is larger than 0, the opening degree of the main-path electronic expansion valve is controlled to be increased by | delta PE |, when the delta ESH is smaller than 0, the delta PE is smaller than 0, and the opening degree of the main-path electronic expansion valve is controlled to be decreased by | delta PE |.

The target value of the auxiliary road superheat degree ESH is an auxiliary road target superheat degree SESH, a second difference value delta ESH = ESH-SESH between the auxiliary road superheat degree and the corrected auxiliary road target superheat degree (namely the current auxiliary road target superheat degree) is calculated, an opening degree change value delta PE of the auxiliary road electronic expansion valve is calculated according to the second difference value, the delta PE value is positively correlated with the delta ESH, and the size of the change value is influenced by the K2 value. When delta ESH is larger than 0, the actual auxiliary road superheat degree ESH is larger than the auxiliary road target superheat degree SESH, the auxiliary road refrigerant flow needs to be increased, ESH is reduced, ESH = SESH, the auxiliary road refrigerant flow is positively correlated with the opening degree of an auxiliary road electronic expansion valve, the opening degree of the auxiliary road electronic expansion valve needs to be increased at the moment, namely delta PE is larger than 0, the opening degree of the auxiliary road electronic expansion valve is increased, the auxiliary road flow is increased, and ESH is reduced until ESH is equal to SESH; similarly, when Δ ESH is less than 0, the opening of the auxiliary electronic expansion valve is correspondingly reduced, the flow of the auxiliary refrigerant is reduced, and the ESH is increased until the ESH is equal to SESH. In order to ensure the flow regulation range of the auxiliary circuit refrigerant, the opening regulation range of the auxiliary circuit electronic expansion valve can be set as [ EVEMIN, EVEMX ], the EVEMIN is the minimum opening value, and the EVEMX is the maximum opening value. In order to ensure that the degree of superheat ESH of the auxiliary road can be within a reasonable degree of superheat range, the target degree of superheat SESH of the auxiliary road can be set with a reasonable degree of superheat range SESHMIN, SESHMAX.

By making the opening degree change value of the auxiliary road electronic expansion valve positively correlated with the second difference value, the auxiliary road refrigerant flow can be increased when the auxiliary road superheat degree is greater than the auxiliary road target superheat degree, the auxiliary road superheat degree is reduced, the auxiliary road refrigerant flow can be reduced when the auxiliary road superheat degree is less than the auxiliary road target superheat degree, the auxiliary road superheat degree is increased, the auxiliary road superheat degree can be always close to or equal to the auxiliary road target superheat degree, the auxiliary road superheat degree is guaranteed to be always in a reasonable range, and the control accuracy of the auxiliary road electronic expansion valve is improved.

In an embodiment, in order to ensure that the main path superheat degree and the sub path superheat degree are within a reasonable superheat degree range, the embodiment provides an implementation manner for correcting the main path target superheat degree and the sub path target superheat degree based on the exhaust superheat degree and the main path subcooling degree, and the implementation manner may be specifically executed with reference to the following steps (1) to (3):

step (1): and when the exhaust superheat degree is smaller than a first preset threshold value, controlling the main road target superheat degree to increase a first numerical value, and controlling the auxiliary road superheat degree to increase a second numerical value.

The first value x1 and the second value x2 may be the same or different, and the ranges of the first value and the second value may be (0,1), the preferred value of the first value x1 is 1, and the preferred value of the second value x2 is 1, for example, the first predetermined threshold value y1 may be the minimum value of the reasonable range of the exhaust superheat degree, such as 20 to 30, and the preferred value is 25.

When the exhaust superheat degree is smaller than a first preset threshold value, the exhaust superheat degree is low, liquid attack risk exists, the main path target superheat degree is controlled to increase a first numerical value, the auxiliary path superheat degree is controlled to increase a second numerical value, the main path electronic expansion valve is closed, the exhaust superheat degree is improved, meanwhile, the auxiliary path electronic expansion valve is closed, the auxiliary path flow is reduced, the heat exchange effect of the economizer is reduced, and the main path supercooling degree is reduced.

Referring to a main road target superheat degree and auxiliary road target superheat degree correction table shown in the following table two, table two shows a main road target superheat degree and auxiliary road target superheat degree correction mode corresponding to the exhaust superheat degree DSH and the main road supercooling degree ESC in different value ranges.

Table two main road target superheat degree and auxiliary road target superheat degree correction table

Step (2): and when the exhaust superheat degree is greater than or equal to a first preset threshold value and less than or equal to a second preset threshold value, controlling the main road target superheat degree to be unchanged, and correcting the auxiliary road target superheat degree according to the main road superheat degree.

The value of the second preset threshold y2 may range from 35 to 45, and a preferred value is 40. When the exhaust superheat degree is larger than or equal to the first preset threshold value and smaller than or equal to the second preset threshold value, the exhaust superheat degree of the air conditioning unit is moderate, the main path target superheat degree is kept unchanged, the opening degree of the main path electronic expansion valve is kept unchanged, and the auxiliary path target superheat degree is corrected by the main path subcooling degree.

As shown in the second table, when the exhaust superheat degree is greater than or equal to the first preset threshold and less than or equal to the second preset threshold (y 1 is greater than or equal to DSH and less than or equal to y 2), if the main road subcooling degree is less than the third preset threshold y3, the auxiliary road target superheat degree is controlled to be reduced by a fourth value x4, and if the main road subcooling degree is greater than or equal to the third preset threshold, the auxiliary road target superheat degree is controlled to be kept unchanged. The value range of the fourth value may be (0,1), for example, and the preferred value of the fourth value x4 is 1. The third preset threshold value y3 may be determined according to a reasonable value range of the supercooling degree when the air conditioner normally operates, such as 6 to 10, and the preferred value is 8.

When y1 is not less than DSH and not more than y2 and ESC is not less than y3, DSH and ESC meet the control requirement, SASH and SESH are kept unchanged, the main-path electronic expansion valve and the auxiliary-path electronic expansion valve do not adjust, and the unit operation reaches a stable state. And (3) when the DSH is not less than y1 and not more than y2 and y3 is more than ESC, controlling the target superheat degree of the auxiliary road to be reduced, correspondingly opening the electronic expansion valve of the auxiliary road to improve the supercooling degree ESC of the main road, and reducing the opening degree of the electronic expansion valve of the auxiliary road, so that the influence on the exhaust superheat degree DSH is small, the exhaust superheat degree DSH is relatively stable, and if the exhaust superheat degree DSH is reduced to be less than y1, returning to the step (1).

And (3): and when the exhaust superheat degree is larger than a second preset threshold value, controlling the main road target superheat degree to reduce a third numerical value, and correcting the auxiliary road target subcooling degree according to the main road subcooling degree.

The value range of the third value can be (0,1), the preferred value of the third value x3 is 1, when the exhaust superheat degree is larger than a second preset threshold value, the exhaust superheat degree of the air conditioning unit is higher, high-temperature protection risks exist, the opening degree of the main-path electronic expansion valve is increased and the exhaust superheat degree is reduced by controlling the main-path target subcooling degree to be reduced, the main-path subcooling degree is reduced along with the opening of the main-path electronic expansion valve, and the adjustment of the main-path subcooling degree is completed by correcting the auxiliary-path target superheat degree.

The main path target superheat degree and the auxiliary path target superheat degree are corrected according to the value range of the exhaust superheat degree, the exhaust superheat degree can be corrected, self-adaptive control of the target superheat degree is used for replacing fixed superheat degree control, the exhaust superheat degree is guaranteed to be in a reasonable range, the problem of two-phase flow noise is avoided, and the use experience of a user is improved.

As shown in the second table, when the degree of superheat of the exhaust gas is greater than the second preset threshold (y 2 < DSH), if the degree of subcooling of the main path is less than or equal to a fourth preset threshold y4, the target degree of superheat of the auxiliary path is controlled to be reduced by a fifth value x5, and if the degree of subcooling of the main path is greater than the fourth preset threshold, the target degree of superheat of the auxiliary path is controlled to be kept unchanged; the fourth preset threshold is greater than the third preset threshold, and the fourth preset threshold y4 may be determined according to a reasonable value range of the supercooling degree when the air conditioner operates normally, such as 13 to 17, and the preferred value is 15. The value of the fifth value x5 may be (0,1), and a value of 1 is preferred.

When y2 is less than DSH and ESC is more than y4, it shows that the opening degree of the auxiliary electronic expansion valve is larger, the control auxiliary target superheat degree is kept unchanged, the auxiliary electronic expansion valve does not make adjustment, and the adjustment of the exhaust superheat degree is adjusted by the opening degree of the main electronic expansion valve. When y2 is smaller than DSH and y4 is larger than or equal to ESC, the target superheat degree of the auxiliary circuit is controlled to be reduced by a fifth value x5, the opening degree of the auxiliary circuit electronic expansion valve is increased, the exhaust superheat degree DSH is reduced, the main circuit supercooling degree ESC is increased until y1 is larger than or equal to DSH and smaller than or equal to y2, or ESC is larger than y4, or the superheat degree of the auxiliary circuit reaches the minimum value within a preset reasonable superheat degree range, or the opening degree of the auxiliary circuit electronic expansion valve reaches the maximum opening degree, or the opening degree of the main circuit electronic expansion valve reaches the minimum opening degree.

The auxiliary road target superheat degree is adjusted according to the value ranges of the exhaust superheat degree and the main road supercooling degree, the overall operation condition of the air conditioning unit is considered, the refrigerant flow adjustment in the unit is adjusted by the regional superheat degree of the main road and the auxiliary road, and is converted into the overall adjustment of the exhaust superheat degree and the main road supercooling degree, the air conditioning unit is in a better operation state, the main road superheat degree, the auxiliary road superheat degree and the exhaust superheat degree are guaranteed, the main road supercooling degree is controlled, the flow distribution proportion is more reasonable, and the reliability of the air conditioning operation is guaranteed.

In the process of executing the enhanced vapor injection control method, the variation range of the control parameters is large under the influence of factors such as the ambient temperature, the starting capacity and the like, when the main electronic expansion valve and the auxiliary electronic expansion valve are always kept unchanged, or when the main electronic expansion valve and the auxiliary electronic expansion valve reach the maximum opening degree or the minimum opening degree and have no regulation space, the operation of the air conditioner is determined to reach a stable state, and the stable state may be a control result which meets the control requirements (all parameters can be in a reasonable range) or a control result which does not reach the reasonable range but has no regulation space of the expansion valve. The reasonable superheat degree range of the main road superheat degree and the main road target superheat degree is set as [ a, b ], the reasonable range of the auxiliary road superheat degree and the auxiliary road target superheat degree is set as [ c, d ], and MAX and MIN are the maximum opening degree and the minimum opening degree of the corresponding opening degree range of a main valve (namely a main road electronic expansion valve) and an auxiliary valve (namely an auxiliary road electronic expansion valve). See the following table of various control results, which shows the parameter values under 7 control results:

table of three kinds of control results

In the control result (1), the DSH is more than or equal to y1 and less than or equal to y2, the ESC is more than or equal to y3, and the main road superheat degree and the auxiliary road superheat degree are both in a reasonable superheat degree range, so that the control target is achieved and the control requirement is met; in the results (3) and (4), the exhaust superheat DSH is higher without influencing the operation reliability of the air conditioner, the opening of the expansion valve has no adjusting space, and the main path supercooling ESC is more than or equal to y3 and meets the control requirement.

In the control result (2), the exhaust superheat DSH is reasonable, but the main-path supercooling ESC is low, the air conditioning unit has noise risk, and the auxiliary-path electronic expansion valve cannot be opened any more; in the control result (5), the exhaust superheat degree DSH is higher, the main circuit supercooling degree ESC is lower, the air conditioning unit has noise risk, and the auxiliary circuit electronic expansion valve can not be opened any more. Therefore, both the control results (2) and (5) have the problem of insufficient supercooling degree, and supplementary control needs to be added to the main circuit electronic expansion valve to reduce noise. In the control results (6) and (7), the exhaust superheat degree is low, no adjusting space exists between the main-path electronic expansion valve and the auxiliary-path electronic expansion valve, the air conditioner has liquid impact risk, and exit control needs to be added.

With respect to the above control results (2) and (5), when the air conditioner reaches the steady state, the method provided by the embodiment further includes: when the state reaches a stable state, judging whether the condition that the supercooling degree is insufficient and the auxiliary electronic expansion valve does not have an adjusting space exists at present, if so, controlling the main electronic expansion valve to periodically reduce the preset opening degree to supplement the supercooling degree until the preset supercooling degree supplement quit condition is met, and quitting the supplementary supercooling degree control.

And when the air conditioner circularly executes the steps S202 to S208 to reach a stable state, judging whether the supercooling degree is insufficient and the auxiliary expansion valve has no adjusting space, if so, starting supercooling degree supplement control to optimize the supercooling degree of the main circuit, controlling the opening degree of the main circuit electronic expansion valve to be reduced by 1pls every 10S until a preset supercooling degree supplement quit condition is reached, and quitting the current supercooling degree supplement control.

The preset supercooling degree supplement exit condition comprises any one of the following conditions:

the exhaust temperature is higher than the preset temperature; the preset temperature may take, for example, 95 degrees;

the supercooling degree of the main path is greater than or equal to a third preset threshold value; namely y3 is not more than ESC;

the main road superheat degree is larger than or equal to the maximum value of a preset range; namely b is less than or equal to ASH;

the main electronic expansion valve reaches the minimum opening MIN.

When y3 is less than or equal to ESC, the control of the main-circuit electronic expansion valve meets the requirement of the main-circuit supercooling degree, when the exhaust temperature is higher than the preset temperature, the unit exhaust reliability is ensured, when b is less than or equal to ASH or the main-circuit electronic expansion valve reaches the minimum opening MIN, the main-circuit electronic expansion valve reaches the regulation limit and cannot be regulated any more, and therefore, the supplementary supercooling degree control is quitted.

The main circuit electronic expansion valve is controlled to be turned off to supplement the supercooling degree when the supercooling degree of the air conditioner is insufficient and the auxiliary circuit expansion valve does not have an adjusting space, so that the supercooling degree of the main circuit is improved, noise of an air conditioning unit is avoided, the supplement control of the condition exceeding the control range is realized, and the operation reliability of the air conditioner is improved.

In a specific embodiment, this embodiment provides a specific embodiment for determining whether there is a condition of insufficient supercooling degree and no conditioned space in the auxiliary electronic expansion valve at present: judging whether the following first condition to fourth condition are met at the same time, if so, determining that the condition that the supercooling degree is insufficient and the auxiliary electronic expansion valve does not have an adjusting space exists at present; wherein the first to fourth conditions include:

under a first condition, the exhaust superheat degree is greater than or equal to a first preset threshold value; namely, satisfying that y1 is not more than DSH;

under the second condition, the main circuit supercooling degree is smaller than a third preset threshold value; namely, y3 is more than ESC;

under a third condition, the main path superheat degree is in a preset range; namely, a is more than ASH and less than b;

a fourth condition that there is no adjustment space for the auxiliary electronic expansion valve; and when the auxiliary road superheat degree reaches the minimum ESH = c in a reasonable superheat degree range or the auxiliary road electronic expansion valve reaches the maximum opening degree, determining that no adjusting space exists in the auxiliary road electronic expansion valve.

Whether the condition that the supercooling degree is insufficient or not is judged according to the exhaust superheat degree, the main path supercooling degree and the main path superheat degree, whether the auxiliary path electronic expansion valve does not have an adjusting space or not is judged according to the auxiliary path superheat degree or the auxiliary path electronic expansion valve, whether the condition that the supercooling degree is insufficient and the auxiliary path electronic expansion valve does not have the adjusting space or not is judged accurately, and noise is prevented from being generated by the air conditioner due to the insufficient supercooling degree.

In view of the above control results (6) and (7), in order to avoid the air conditioner from generating liquid impact (liquid refrigerant impacts the compressor), the method provided by this embodiment further includes: and when the stable state is reached, if the liquid impact risk exists and no adjusting space exists between the main electronic expansion valve and the auxiliary electronic expansion valve, the jet enthalpy increasing heating mode is controlled to exit.

When the air conditioner circularly executes the steps S202 to S208 to reach a stable state, acquiring the current exhaust superheat degree, determining that a liquid impact risk exists when the exhaust superheat degree is low, judging whether a main-path electronic expansion valve and an auxiliary-path electronic expansion valve have an adjusting space, if not, exiting an enhanced vapor injection heating mode, controlling an auxiliary-path vapor injection solenoid valve and the auxiliary-path electronic expansion valve to be closed, and enabling the main-path electronic expansion valve to enter a conventional heating mode to operate. The air conditioner is controlled to exit the enhanced vapor injection heating mode in time when the air conditioner has liquid impact risk and the main-path electronic expansion valve and the auxiliary-path electronic expansion valve do not have adjusting space, so that liquid impact can be effectively prevented, and the operation reliability of the air conditioner is ensured.

In a specific embodiment, when the following conditions one-five are simultaneously met, determining that the liquid impact risk exists and no adjusting space exists between the main-path electronic expansion valve and the auxiliary-path electronic expansion valve; wherein the first to fifth conditions include:

the method comprises the following steps that firstly, the exhaust superheat degree is smaller than a first preset threshold value; namely DSH < y1;

secondly, the target superheat degree of the main road reaches the maximum value of the preset superheat degree range of the main road; namely SASH = b;

thirdly, the target superheat degree of the auxiliary road reaches the maximum value of the preset superheat degree range of the auxiliary road; namely SESH = d;

fourthly, the main-path electronic expansion valve reaches the minimum opening degree, or the main-path superheat degree reaches the maximum value of the main-path preset superheat degree range; namely ASH = b, or the main-path electronic expansion valve is EVMMIN;

the condition five is that the auxiliary circuit electronic expansion valve reaches the minimum opening degree, or the auxiliary circuit superheat degree reaches the maximum value of the auxiliary circuit preset superheat degree range; namely, ESH = d, or the auxiliary electronic expansion valve is EVEMIN.

Under the normal condition, when the air conditioning unit operates in a heating mode, a motor generates heat in the compression process of the compressor, the exhaust superheat degree is generally far higher than the return superheat degree (specifically, the exhaust superheat degree can be calculated by an isentropic coefficient of the compressor), therefore, the exhaust superheat degree DSH is preferably kept to be more than y1 ℃ in the heating mode, liquid impact can be effectively prevented, whether liquid impact risks exist or not is judged according to the exhaust superheat degree, the main path target superheat degree, the auxiliary path target superheat degree, the main path electronic expansion valve and the auxiliary path electronic expansion valve, whether liquid impact risks exist in the air conditioner or not can be judged in time, liquid impact is avoided, and the stability of air injection enthalpy gain control of the air conditioner is improved.

According to the enhanced vapor injection control method of the air conditioner, cooperative control of the main-path electronic expansion valve and the auxiliary-path electronic expansion valve is achieved by correcting the main-path superheat degree and the auxiliary-path superheat degree, adaptive reasonable distribution of the main-path refrigerant flow and the auxiliary-path refrigerant flow under different working conditions can be achieved, the air conditioning unit is in a better running state, the control strategy is more refined, control of the refrigerant subcooling degree is considered on the premise that the main-path superheat degree, the auxiliary-path superheat degree and the exhaust superheat degree are guaranteed, the flow distribution proportion is more reasonable, and meanwhile the problem of two-phase flow noise is avoided.

Corresponding to the enhanced vapor injection control method of the air conditioner provided in the above embodiment, an embodiment of the present invention provides an example of controlling an electronic expansion valve of an enhanced vapor injection air conditioning system by using the enhanced vapor injection control method of the air conditioner, which may be specifically executed by referring to the following steps:

step 1, controlling a main-path electronic expansion valve (hereinafter referred to as a main valve) and a secondary-path electronic expansion valve (hereinafter referred to as a secondary valve) by using superheat degree.

Main valve control: calculating ASH, wherein ASH = TA-TC is superheat degree of an outlet of the heat exchanger, starting from system circulation, the ASH is superheat degree of a refrigerant of the main enthalpy injection path back to the compressor, and a difference value delta ASH = ASH-SASH is set as an ASH target value SASH; the main valve opening variation value Δ PM = Δ ASH × K1, the Δ PM value is positively correlated with Δ ASH, the magnitude is affected by the value K1, when Δ ASH > 0, the main valve opening is controlled to increase, ASH is reduced, ASH = SASH, and when Δ ASH < 0, the main valve opening is controlled to decrease, ASH is increased, ASH = SASH.

Controlling an auxiliary valve: calculating ESH, wherein ESH = TO-TI is superheat degree of the enthalpy injection auxiliary circuit refrigerant returned TO the compressor, and setting an ESH target value as SESH, wherein a difference value delta ESH = ESH-SESH, an auxiliary valve opening change value delta PE = delta ESH × K2, K2 is an auxiliary valve opening adjusting coefficient, K2 is more than 0, namely the delta PE value is positively correlated with the delta ESH, and the size is influenced by the K2 value. When delta ESH is larger than 0, controlling the opening of the auxiliary valve to increase the flow of the auxiliary path refrigerant, and reducing ESH so that ESH = SESH; and when the delta ESH is less than 0, controlling the opening of the auxiliary valve to be small, and increasing the ESH so that the ESH = SESH.

And step 2, correcting the superheat degree of the main road target and the superheat degree of the auxiliary road target.

In an actual use scene, when the operation ranges of the unit, such as outdoor environment temperature, indoor environment temperature and the capacities of an inner machine and an outer machine, are greatly different, the operation parameters of the compressor, such as frequency, suction pressure and exhaust pressure, are also different correspondingly, the flow of the unit cannot be taken into consideration by controlling the flow by using a fixed superheat degree, and the operation states of the compressor and the unit cannot be taken into consideration. See the table of the relationship of the influence of the target superheat degree change on the air conditioning unit as shown in the following table four:

table four-target superheat degree change influence relation table for air conditioning unit

As shown in Table four, scene (1) SASH +1: as SASH +1 and ASH remain unchanged, Δ ASH = -1, resulting in a main valve opening being closed small, ASH +1, eventually Δ ASH =0; the exhaust superheat degree DSH rises due to the rise of ASH, the main path flow is reduced at the moment, and the main path outlet supercooling degree ESC ≠ under the same inlet state.

Scene (2): Δ ASH =1, due to SASH-1 and ASH remaining unchanged, resulting in a large main valve opening, ASH-1, eventually Δ ASH =0; the exhaust superheat DSH is reduced due to the reduction of ASH, the main path flow is increased, and the main path outlet supercooling degree ESC ↓isin the same inlet state.

Scene (3): as SESH +1 and ESH remain unchanged, Δ ESH = -1, resulting in small auxiliary valve opening, ESH +1, and finally Δ ESH =0; the exhaust superheat DSH rises due to ESH rising, at the moment, the flow of the auxiliary path is reduced, the heat exchange effect of the economizer is reduced, and the main path supercooling degree ESC ↓.

Scene (4): when the opening degree of the auxiliary valve is large, ESH-1 and finally delta ESH =0, the exhaust transition degree DSH is reduced due to ESH reduction because SESH-1 and ESH are kept unchanged, the flow rate of the auxiliary path is increased, the heat exchange effect of the economizer is enhanced, and the supercooling degree of the main path ESC ≦ ESC ≦ 1.

In contrast, because the main circuit refrigerant flow is much larger than the auxiliary circuit refrigerant flow, the main valve has significantly larger regulating effect on DSH and ESC than the auxiliary valve, and the dual-valve cooperative control will follow the principle of "main valve first, auxiliary valve assist", control target range: DSH is more than or equal to 25 and less than or equal to 40, ESC is more than or equal to 8, ASH and ESH are positioned in the superheat degree range, and the condition that the compressor has no liquid impact risk, the compressor is positioned in a high-efficiency operation area (the exhaust temperature is reasonable) and no two-phase flow refrigerant noise risk is ensured.

The correction control logic of the main road target superheat degree and the auxiliary road target superheat degree is as follows: limiting the value ranges of SASH, SESH, ASH and ESH according to the reasonable range of the superheat degree, and limiting the opening ranges of the main valve and the auxiliary valve; and determining the corrected values of SASH and SESH according to the temperature interval of the current DSH and ESC, controlling the main valve according to the difference delta ASH between SASH and ASH after correction, and controlling the auxiliary valve according to the difference delta ESH between SESH and ESH after correction. After the main valve acts, the flow of the main refrigerant changes, so that ASH changes, and DSH and ESC change; after the auxiliary valve acts, the flow of the auxiliary path refrigerant changes, so that ESH changes, DSH and ESC change, and DSH adjustment and ESC adjustment are realized.

And correcting the main road target superheat degree according to the DSH and the ESC, and referring to a main road target superheat degree correction value table shown in the following table five:

table five main path target superheat correction value dereferencing table

When DSH is less than 25, the exhaust superheat degree is low, and the liquid impact risk exists, the main path target superheat degree SASH correction result +1 correspondingly reduces the main valve closing, the DSH is improved, and meanwhile, the ESC is improved along with the reduction of the main valve closing, and the noise risk is reduced.

When DSH is more than or equal to 25 and less than or equal to 40, the exhaust superheat degree is moderate, SASH is kept unchanged, correspondingly, a main valve is kept unchanged, and the ESC regulation is finished by SESH correction.

When the DSH is larger than 40, the exhaust superheat degree is higher, the system has high-temperature protection risk, the main path target superheat degree correction result-1 is correspondingly larger than the main valve, the DSH is reduced, the ESC is reduced along with the larger main valve, and the ESC adjustment is completed by SESH correction.

And correcting the auxiliary road target superheat degree according to the DSH and the ESC, and referring to a value table of a correction value of the auxiliary road target superheat degree shown in the following six tables:

table six auxiliary road target superheat correction value dereferencing table

When the DSH is less than 25, the auxiliary road target superheat SESH correction result is +1, the auxiliary valve is correspondingly closed to be small, the DSH is improved, the ESC is closed to be small along with the closing of the auxiliary valve, and when the ESC is larger than or equal to 8, the noise risk control requirement can be still met; when ESC is less than 8, the priority valve is closed to meet the control requirement of DSH, and the liquid impact risk is greater than the noise risk.

When DSH is more than or equal to 25 and less than or equal to 40 and ESC is more than or equal to 8, DSH and ESC meet the control requirement, SESH is kept unchanged, and the auxiliary valve is not adjusted; when DSH is more than or equal to 25 and less than or equal to 40 and ESC is less than 8, SESH correction result-1, the opening of the auxiliary valve greatly improves ESC, the opening of the auxiliary valve is small, the influence on DSH is small, DSH is relatively stable, and if DSH continuously drops to DSH less than 25, adjustment is carried out according to the DSH less than 25.

When DSH is more than 40 and ESC is more than 15, the opening of the auxiliary valve is larger, SESH is kept unchanged, the auxiliary valve is not adjusted, and DSH adjustment is mainly carried out by the main valve; when DSH is more than 40 and ESC is more than or equal to 15 and more than or equal to 8 or DSH is more than or equal to 40 and ESC is less than or equal to 8, SESH correction result-1, the opening of the auxiliary valve is large, DSH is reduced, ESC is raised until DSH is more than or equal to 25 and less than or equal to 40 or ESC is more than or equal to 15 or ESH is minimum or the opening of the auxiliary valve is maximum.

Actually, the variation range of the control parameter is large under the influence of the environmental temperature, the boot capacity, and the like, and the possible control results are shown in the following table seven:

table seven control results table

The result (1) meets the control requirements. As a result (2), DSH is reasonable but ESC is small, the system has noise risk, the opening of the auxiliary valve can not be opened any more, and the main valve needs to be additionally controlled. And the DSH is higher without affecting the reliability, the opening degree has no adjusting space, the ESC meets the requirement, and the control result meets the control requirement. As a result (5) DSH is higher and ESC is lower, the system is in noise risk, the opening of the auxiliary valve can not be opened any more, and the main valve needs to be additionally controlled. As a result (6) & result (7) shows that DSH is low and there is no adjustment space for opening, the system has a risk of liquid hammer and needs to be additionally withdrawn from the control system.

And 3, performing supplementary control on the control result.

And supplement control I: the supercooling degree control was optimized for the results (2) and (5).

The determination condition is

When the judgment conditions (1) (2) (3) (4) or (1) (2) (3) (5) are met, the supercooling degree is considered to be insufficient, the auxiliary valve has no adjusting space, and the opening of the main valve is directly adjusted, and the adjusting method comprises the following steps: at intervals of 10S, the main valve opening is reduced by 1pls until the following exit condition is reached:

the exit conditions are as follows:

that is, when any one of the above-described conditions (1), (2), (3), and (4) is satisfied, the current supercooling degree supplement control is exited.

And (5) supplementary control: control for increasing exhaust superheat degree too low for result control (6) and (7)

Determination conditions

When the judgment conditions (1), (2) and (3) are met, any one of the conditions (4), (5) and any one of the conditions (6) and (7) are met, the system is determined to have liquid impact risk, the main electronic expansion valve and the auxiliary electronic expansion valve have no regulating capacity, and the injection enthalpy control is quit at the moment. And (4) exiting action: and closing the auxiliary circuit electromagnetic valve SVI, closing the auxiliary electronic expansion valve, and controlling the main electronic expansion valve in a conventional heating mode.

Corresponding to the enhanced vapor injection control method of the air conditioner provided in the above embodiment, an embodiment of the present invention provides an enhanced vapor injection control device of an air conditioner, which can be applied to an air conditioner, and referring to a schematic structural diagram of the enhanced vapor injection control device of the air conditioner shown in fig. 3, the device includes the following modules:

the detection module 31 is configured to detect an exhaust superheat degree, a main path supercooling degree, a main path superheat degree, and an auxiliary path superheat degree when the vehicle operates in the enhanced vapor injection heating mode; the main path supercooling degree is the difference value between the saturation temperature corresponding to the exhaust pressure and the outlet temperature of the main path of the economizer, the main path superheat degree is the difference value between the outlet temperature of the heat exchanger and the temperature in the pipe, and the auxiliary path superheat degree is the difference value between the outlet temperature and the inlet temperature of the auxiliary path of the economizer.

The correction module 32 is used for correcting the main road target superheat degree and the auxiliary road target superheat degree based on the exhaust superheat degree and the main road subcooling degree so as to enable the main road target superheat degree and the auxiliary road target superheat degree to enter a preset reasonable superheat degree range; the exhaust superheat degree and the main path supercooling degree correspond to a preset main path target superheat degree correction value and a preset auxiliary path target superheat degree correction value.

The first control module 33 is configured to control the opening of the main-path electronic expansion valve according to the main-path superheat degree and the corrected main-path target superheat degree.

And the second control module 34 is used for controlling the opening of the auxiliary road electronic expansion valve according to the auxiliary road superheat degree and the corrected auxiliary road target superheat degree.

And the circulating execution module 35 is configured to trigger the detection module to start running until a stable state is reached after the second control module finishes executing.

The air injection enthalpy gain control device of the air conditioner provided by the embodiment can realize self-adaptive control on the main road target superheat degree and the auxiliary road target superheat degree by correcting the main road target superheat degree and the auxiliary road target superheat degree according to the exhaust superheat degree and the main road supercooling degree under the air injection enthalpy gain heating mode, and further can realize cooperative control on the main road electronic expansion valve and the auxiliary road electronic expansion valve, so that the refrigerant flow distribution in the air conditioning unit is more reasonable, the noise problem is avoided, and the operation reliability of the air conditioner is improved.

The device provided by the embodiment has the same implementation principle and technical effect as the foregoing embodiment, and for the sake of brief description, reference may be made to the corresponding contents in the foregoing method embodiment for the portion of the embodiment of the device that is not mentioned.

Corresponding to the enhanced vapor injection control method of the air conditioner provided in the above embodiment, the present embodiment provides an air conditioner, which includes a computer readable storage medium storing a computer program and a processor, and when the computer program is read and executed by the processor, the enhanced vapor injection control method of the air conditioner provided in the above embodiment is implemented.

The present embodiment further provides a computer-readable storage medium, where a computer program is stored, and when the computer program is executed by a processor, the computer program implements the processes of the above embodiment of the enhanced vapor injection control method for an air conditioner, and can achieve the same technical effects, and in order to avoid repetition, the detailed description is omitted here. The computer-readable storage medium may be a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk.

Of course, those skilled in the art can understand that all or part of the processes in the methods according to the above embodiments may be implemented by instructing a control device to implement the methods according to the above embodiments by a computer, and the program may be stored in a computer-readable storage medium, and when executed, the program may include the processes according to the above method embodiments, where the storage medium may be a memory, a magnetic disk, an optical disk, or the like.

Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Finally, it should also be noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising a … …" does not exclude the presence of another identical element in a process, method, article, or apparatus that comprises the element.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. The enhanced vapor injection control device of the air conditioner and the air conditioner disclosed by the embodiment correspond to the enhanced vapor injection control method of the air conditioner disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the description of the method part.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An enhanced vapor injection control method of an air conditioner is characterized by comprising the following steps:

step S202, detecting exhaust superheat degree, main path supercooling degree, main path superheat degree and auxiliary path superheat degree under the condition of operating in an enhanced vapor injection heating mode; the main path supercooling degree is the difference value between the saturation temperature corresponding to the exhaust pressure and the outlet temperature of the main path of the economizer, the main path superheat degree is the difference value between the outlet temperature of the heat exchanger and the temperature in the pipe, and the auxiliary path superheat degree is the difference value between the outlet temperature and the inlet temperature of the auxiliary path of the economizer;

step S204, correcting the main road target superheat degree and the auxiliary road target superheat degree based on the exhaust superheat degree and the main road supercooling degree so as to enable the main road target superheat degree and the auxiliary road target superheat degree to enter a preset reasonable superheat degree range; the exhaust superheat degree and the main path supercooling degree correspond to a preset main path target superheat degree correction value and a preset auxiliary path target superheat degree correction value;

step S206, controlling the opening degree of the main-path electronic expansion valve according to the main-path superheat degree and the corrected main-path target superheat degree;

step S208, controlling the opening of the auxiliary road electronic expansion valve according to the auxiliary road superheat degree and the corrected auxiliary road target superheat degree;

the steps S202 to S208 are repeatedly executed until a steady state is reached.

2. The enhanced vapor injection control method of an air conditioner according to claim 1, wherein said step of correcting the main path target superheat degree and the sub path target superheat degree based on the exhaust superheat degree and the main path subcooling degree comprises:

when the exhaust superheat degree is smaller than a first preset threshold value, controlling the main road target superheat degree to increase by a first value, and controlling the auxiliary road superheat degree to increase by a second value;

when the exhaust superheat degree is larger than or equal to the first preset threshold value and smaller than or equal to a second preset threshold value, controlling the main path target superheat degree to be unchanged, and correcting the auxiliary path target superheat degree according to the main path subcooling degree;

and when the exhaust superheat degree is larger than the second preset threshold value, controlling the main road target superheat degree to reduce a third numerical value, and correcting the auxiliary road target subcooling degree according to the main road subcooling degree.

3. The enhanced vapor injection control method of an air conditioner according to claim 2, wherein said step of correcting said secondary target superheat degree according to said primary subcooling degree comprises:

under the condition that the exhaust superheat degree is larger than or equal to the first preset threshold and smaller than or equal to the second preset threshold, if the main road supercooling degree is smaller than a third preset threshold, controlling the auxiliary road target superheat degree to be reduced by a fourth value, and if the main road supercooling degree is larger than or equal to the third preset threshold, controlling the auxiliary road target superheat degree to be kept unchanged;

under the condition that the exhaust superheat degree is larger than the second preset threshold, if the main path supercooling degree is smaller than or equal to a fourth preset threshold, controlling the auxiliary path target superheat degree to be reduced by a fifth value, and if the main path supercooling degree is larger than the fourth preset threshold, controlling the auxiliary path target superheat degree to be kept unchanged; wherein the fourth preset threshold is greater than the third preset threshold.

4. The enhanced vapor injection control method of an air conditioner according to claim 1, wherein the step of controlling the opening degree of the main electronic expansion valve according to the main superheat degree and the corrected main target superheat degree comprises:

calculating the difference value between the main path superheat degree and the corrected main path target superheat degree, and recording the difference value as a first difference value;

controlling the opening change value of the main electronic expansion valve to be delta PM = delta ASH K1; wherein Δ ASH is the first difference, K1 is a main path electronic expansion valve adjustment coefficient, and K1 is greater than 0.

5. The enhanced vapor injection control method of an air conditioner according to claim 1, wherein said step of controlling the opening degree of the auxiliary electronic expansion valve based on the degree of superheat of the auxiliary and the corrected target degree of superheat of the auxiliary comprises:

calculating the difference value between the auxiliary road superheat degree and the corrected auxiliary road target superheat degree, and recording the difference value as a second difference value;

controlling the opening change value of the auxiliary electronic expansion valve to be delta PE = delta ESH × K2; and the delta ESH is the second difference value, K2 is the adjustment coefficient of the auxiliary electronic expansion valve, and K2 is more than 0.

6. The enhanced vapor injection control method of an air conditioner according to claim 3, further comprising:

when the steady state is reached, judging whether the condition that the supercooling degree is insufficient and the auxiliary electronic expansion valve does not have an adjusting space exists at present, if so, controlling the main electronic expansion valve to periodically reduce the preset opening degree to supplement the supercooling degree until the preset supercooling degree supplement exit condition is met, and exiting the supplementary supercooling degree control; the preset supercooling degree supplement exit condition comprises any one of the following conditions:

the exhaust temperature is higher than the preset temperature;

the main path supercooling degree is greater than or equal to a third preset threshold value;

the main path superheat degree is larger than or equal to the maximum value of the preset range;

and the main electronic expansion valve reaches the minimum opening.

7. The enhanced vapor injection control method of an air conditioner according to claim 6, wherein said step of determining whether there is a condition of insufficient subcooling and no conditioning space for the auxiliary electronic expansion valve comprises:

judging whether the following first condition to fourth condition are met at the same time, if so, determining that the condition that the supercooling degree is insufficient and the auxiliary electronic expansion valve does not have an adjusting space exists at present; wherein the first to fourth conditions include:

a first condition that the exhaust superheat degree is greater than or equal to the first preset threshold value;

under a second condition, the supercooling degree of the main path is smaller than the third preset threshold value;

a third condition that the main path superheat degree is within a preset range;

and under the fourth condition, the auxiliary road superheat degree reaches the minimum value in a reasonable superheat degree range, or the auxiliary road electronic expansion valve reaches the maximum opening degree.

8. The enhanced vapor injection control method of an air conditioner according to claim 3, further comprising:

and when the stable state is reached, if the liquid impact risk exists and no adjusting space exists between the main-path electronic expansion valve and the auxiliary-path electronic expansion valve, the enhanced vapor injection heating mode is controlled to exit.

9. The enhanced vapor injection control method of an air conditioner according to claim 8, further comprising:

when the following conditions from one to five are met, determining that the liquid impact risk exists and no adjusting space exists between the main-path electronic expansion valve and the auxiliary-path electronic expansion valve; wherein the first to fifth conditions include: the exhaust superheat degree is smaller than the first preset threshold value under the condition one;

secondly, the target superheat degree of the main path reaches the maximum value of a preset superheat degree range of the main path;

thirdly, the target degree of superheat of the auxiliary road reaches the maximum value of a preset degree of superheat range of the auxiliary road;

fourthly, the main-path electronic expansion valve reaches the minimum opening degree, or the main-path superheat degree reaches the maximum value of the main-path preset superheat degree range;

and fifthly, the auxiliary circuit electronic expansion valve reaches the minimum opening degree, or the auxiliary circuit superheat degree reaches the maximum value of the auxiliary circuit preset superheat degree range.

10. An enhanced vapor injection control device of an air conditioner, comprising:

the detection module is used for detecting the exhaust superheat degree, the main path supercooling degree, the main path superheat degree and the auxiliary path superheat degree under the condition of operating in the enhanced vapor injection heating mode; the main path supercooling degree is the difference value between the saturation temperature corresponding to the exhaust pressure and the outlet temperature of the main path of the economizer, the main path superheat degree is the difference value between the outlet temperature of the heat exchanger and the temperature in the pipe, and the auxiliary path superheat degree is the difference value between the outlet temperature and the inlet temperature of the auxiliary path of the economizer;

the correction module is used for correcting the main road target superheat degree and the auxiliary road target superheat degree based on the exhaust superheat degree and the main road supercooling degree so as to enable the main road target superheat degree and the auxiliary road target superheat degree to enter a preset reasonable superheat degree range; the exhaust superheat degree and the main path supercooling degree correspond to a preset main path target superheat degree correction value and a preset auxiliary path target superheat degree correction value;

the first control module is used for controlling the opening degree of the main road electronic expansion valve according to the main road superheat degree and the corrected main road target superheat degree;

the second control module is used for controlling the opening of the auxiliary road electronic expansion valve according to the auxiliary road superheat degree and the corrected auxiliary road target superheat degree;

and the circulating execution module is used for triggering the detection module to start running until the second control module finishes executing until a stable state is reached.

11. An air conditioner comprising a processor and a computer readable storage medium storing a computer program which, when read and executed by the processor, implements the method of any one of claims 1-7.