CN109425069B - Control method for electronic expansion valve during heating - Google Patents

Control method for electronic expansion valve during heating Download PDF

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CN109425069B
CN109425069B CN201710709071.2A CN201710709071A CN109425069B CN 109425069 B CN109425069 B CN 109425069B CN 201710709071 A CN201710709071 A CN 201710709071A CN 109425069 B CN109425069 B CN 109425069B
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tdsh
delta
expansion valve
electronic expansion
target
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CN109425069A (en
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侯丽峰
秦宪
赵攀
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Ningbo Aux Electric Co Ltd
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Ningbo Aux Electric Co Ltd
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B49/00—Arrangement or mounting of control or safety devices
    • F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B41/00—Fluid-circulation arrangements
    • F25B41/30—Expansion means; Dispositions thereof
    • F25B41/31—Expansion valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B41/00—Fluid-circulation arrangements
    • F25B41/30—Expansion means; Dispositions thereof
    • F25B41/31—Expansion valves
    • F25B41/34—Expansion valves with the valve member being actuated by electric means, e.g. by piezoelectric actuators
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2600/00—Control issues
    • F25B2600/25—Control of valves
    • F25B2600/2513—Expansion valves
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
    • Y02B30/70—Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mechanical Engineering (AREA)
  • Thermal Sciences (AREA)
  • General Engineering & Computer Science (AREA)
  • Air Conditioning Control Device (AREA)
  • Compression-Type Refrigeration Machines With Reversible Cycles (AREA)

Abstract

The invention discloses a control method of a HEATING electronic expansion valve, which controls the opening degree of the expansion valve by detecting exhaust superheat TdSH and suction superheat SH _ HEATING, controls the trend of continuous rising of exhaust temperature by opening an electronic expansion valve in advance when the temperature of the exhaust superheat is found to be increased gradually along with time, controls the gradual increasing phenomenon of the exhaust superheat, and keeps the operation of the exhaust superheat in a safe range by reducing the opening degree of the electronic expansion valve in advance through a calculation formula when the exhaust superheat is found to be in a descending trend along with time. The invention realizes the simultaneous control of the suction superheat degree and the exhaust superheat degree through one component, thereby not only ensuring the continuous heat supply of the indoor unit, but also ensuring the reliability of the outdoor compressor, further ensuring the normal operation of the whole system and prolonging the service life.

Description

Control method for electronic expansion valve during heating
Technical Field
The invention relates to the technical field of air conditioner control, in particular to a control method of a heating electronic expansion valve.
Background
One outdoor unit of the variable frequency air conditioner can be used for driving a plurality of indoor units, and one indoor unit can run during running or a plurality of indoor units can run simultaneously during running. The variable frequency air conditioner comprises an indoor unit control system and an outdoor control system, wherein the indoor unit control system is responsible for reading a temperature sensor of the actual temperature of an indoor air conditioning room, the outdoor control system is responsible for reading data of the temperature sensor and transmitting the data to the outdoor control system, the conventional one-drive-multiple variable frequency control is adopted, a heating mode electronic expansion valve is controlled according to air suction superheat degree (air suction temperature of a compressor-low pressure to drinking saturation temperature), and a low-temperature heating mode is adopted.
The patent document with the application number of CN106482411A and the patent name of the control method for preventing the liquid impact of the multi-split air conditioner compressor discloses a control method, wherein the control method comprises the steps of classifying the liquid impact degree of the compressor, classifying the liquid impact degree of the compressor into a plurality of grades according to the exhaust superheat degree of the compressor, calculating the exhaust superheat degree of the compressor, judging whether the liquid impact exists or not and judging the grade of the corresponding liquid impact degree, and respectively adjusting and controlling the control mode according to the severity of the liquid compression, thereby avoiding the mechanical damage of the liquid compression.
However, in the operation process of the air conditioner, if only the suction superheat degree of the outdoor heat exchanger or the exhaust superheat degree is controlled, the reliable operation of the whole machine is difficult to ensure.
Disclosure of Invention
The invention provides a control method of a heating electronic expansion valve, which realizes the simultaneous control of suction superheat and exhaust superheat through one part and ensures the reliability of an outdoor compressor, thereby ensuring the normal operation of the whole system and prolonging the service life.
The technical scheme of the invention is realized as follows:
a control method for a heating electronic expansion valve is characterized by comprising the following steps: it comprises the following steps:
s1: firstly, detecting the exhaust superheat degree, and judging whether the exhaust superheat degree TdSH is in a proper range or not, wherein T is1≤TdSH≤T2If yes, then go to step S2; if not, go to S3;
s2: the T is1≤TdSH≤T2The control system of the indoor unit controls the opening of the electronic expansion valve according to the suction superheat degree, the adjustment of the started expansion valve is determined by the suction superheat degree SH _ HEATING, and the adjustment of the HEATING electronic expansion valve is performed according to PTarget opening degree＝PCurrent opening degreeAdjusting the + delta P, and calculating delta P1;
s3: if the starting detects that the exhaust superheat degree is not in the proper range, the TdSH is judged<T1Or TdSH > T2If TdSH > T2Then proceed to S4; if TdSH<T1Then proceed to S5;
s4: if the detected exhaust superheat degree TdSH is more than T2Adjusting the heating electronic expansion valve according to a first control mode of the exhaust superheat degree TdSH, and calculating delta P2;
s5: if the exhaust superheat degree TdSH is detected<T1In accordance with the second control method of the exhaust superheat TdSH, the heating electronic expansion valve is adjusted to calculate Δ P3.
S6, controlling the heating electronic expansion valve to adjust Δ P, when Δ P1 is greater than Δ P3, the Δ P is Δ P3; when the delta P1 is less than the delta P2, the delta P is delta P2; otherwise Δ P ═ Δ P1.
Preferably, in step S2, the degree of superheat SH _ heatingt inspiration-PS _ TEMP-SHs _ heatingt is a target degree of superheat SHs _ heatingt based on T inspiration-PS _ TEMPOuter ringThe temperature is determined.
Further, when T isOuter ringThe target value SHS _ HEATING of the superheat degree is equal to or less than-3 ℃, and the target value SHS _ HEATING is equal to 2 ℃; when the temperature is lower than-3 ℃ and lower than TOuter ringThe target value SHS _ HEATING of the superheat degree is equal to or less than 6 ℃, and the target value SHS _ HEATING of the superheat degree is equal to 1 ℃; when T isOuter ringWhen the temperature is higher than 6 ℃, the target superheat value SHS _ heatingis 0 ℃.
Preferably, the heating electronic expansion valve adjustment action Δ P1 is related to TSH current and Δ TSH, Δ P1 increasing with increasing TSH and increasing with increasing Δ TSH.
Furthermore, the adjustment step number of the delta P1 is more than or equal to 5 and less than or equal to 6 in the delta P1.
Preferably, in step S4, the first control method of the degree of superheat TdSH of exhaust gas is controlled as follows:
s41: if the temperature is at the target temperature T according to the exhaust superheat degree TdSH2Range operation, i.e. TdSH ═ Texhaust-Pd _ temp-T2Calculating whether TdSH reaches the target T2If not, and TdSH > T2According to the target temperature T2If the control is certain, the heating electronic expansion valve is forbidden to be closed;
s42: after the heating electronic expansion valve is opened for a period of time, whether TdSH reaches the target T or not is calculated2If not, the process returns to S41, and if TdSH reaches the target T2Is controlled in accordance with the range around the target T2To the target T2Upper and lower limit ranges, upper limit ranges: TdSH > TPIf TdSH is equal to TP(ii) a The lower limit range: TdSH < -TPThen TdSH ═ TP；
S43: if TdSH is more than 0.5 ℃ and less than 0.5 ℃, the TdSH is equal to 0 ℃;
s44: obtaining the exhaust superheat slope by the system operation of the current parameter TdSH and the previous time of the previous parameter TdSH, and calculating delta TdSH as TdSH-TdSH previous time;
s45: giving an upper limit range and a lower limit range of the delta TdSH, namely when the delta TdSH is calculated to be more than M, the delta TdSH is equal to the value of M, when the delta TdSH is less than-M, the delta TdSH is equal to the value of-M, and when the temperature is more than-0.5 ℃ and less than the temperature is less than the temperature of 0.5 ℃, the opening degree of the current electronic expansion valve is kept, and no adjustment is made;
s46: by the calculation formula:
Figure BDA0001382238570000031
Figure BDA0001382238570000032
and obtaining the specific electronic expansion valve regulating step number delta P2.
Further, the boundary value T of the T target of the exhaust line2＝42℃，T2Upper limit range value T ofP10 ℃ target T2The range of (A) is controlled to be 32-52 ℃, the upper limit range M of delta TdSH is 5 ℃, and the maximum valve opening N of the heating electronic expansion valve adjusting step number is 8 steps.
Preferably, in step S5, the second control method of the degree of superheat TdSH of exhaust gas is controlled as follows:
s51: if the temperature is at the target temperature T according to the exhaust superheat degree TdSH1Range operation, i.e. TdSH ═ Texhaust-Pd _ Temp-T1(ii) a Calculating whether TdSH reaches target T1If not, and TdSH < T1At the time, according to the target temperature T1Certain control is carried out, and the opening of the electronic expansion valve is forbidden;
s52: after the heating electronic expansion valve is closed for a period of time, whether TdSH reaches the target T or not is calculated1If not, the process returns to S51, and if TdSH reaches the target T1Is controlled in accordance with the range around the target T1To the target T1Upper and lower limit ofWall, TdSH > TqIf TdSH is equal to Tq(ii) a The lower limit range: TdSH < -TqThen TdSH ═ Tq；
S53: if TdSH is more than 0.5 ℃ and less than 0.5 ℃, the TdSH is equal to 0 ℃;
s54: obtaining the exhaust superheat slope by the system operation of the current parameter TdSH and the previous time of the previous parameter TdSH, and calculating delta TdSH as TdSH-TdSH previous time;
s55: giving an upper limit range and a lower limit range of the delta TdSH, namely when the delta TdSH is calculated to be more than R, the delta TdSH is equal to R, when the delta TdSH is less than-R, the delta TdSH is equal to-R, and when the temperature is more than-0.5 ℃ and is less than the temperature of 0.5 ℃, the delta TdSH is equal to 0 ℃, the opening degree of the current electronic expansion valve is kept, and no adjustment is made;
s56: by the calculation formula:
Figure BDA0001382238570000041
Figure BDA0001382238570000042
and obtaining the specific regulating step number of the electronic expansion valve.
Further, the boundary value T of the T target of the exhaust line1＝18℃，T1Upper limit range T ofq10 deg.C, target T1The range of (A) is controlled to be 8-28 ℃, the upper limit range R of delta TdSH is 5 ℃, and the maximum valve opening S of the heating electronic expansion valve adjusting step number is 8 steps.
The invention has the following beneficial effects: the control method of the heating electronic expansion valve comprises the control of a plurality of targets, and the technical problem to be solved is to realize the simultaneous control of the suction superheat degree and the exhaust superheat degree through one part, control a plurality of target temperatures through one electronic expansion valve part, and control the suction superheat degree of an outdoor heat exchanger and the exhaust superheat degree of an outdoor compressor, so that the continuous heat supply of an indoor unit is ensured, the reliability of the outdoor compressor is also ensured, the normal operation of the whole system is ensured, and the service life is prolonged.
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 is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a schematic diagram illustrating the control principle of a control method for a heating electronic expansion valve according to the present invention;
fig. 2 is a schematic diagram illustrating a trend of a calculation example of an electronic expansion valve in a heating process in a control method of a heating electronic expansion valve according to the present invention;
FIG. 3 is a flow chart illustrating a control method for a heating electronic expansion valve according to the present invention;
wherein: 1. gas-liquid separator, 2, compressor, 3, exhaust temperature sensor, 4, condenser, 5, condenser middle temperature sensor, 6, defrost sensor, 7, outdoor environment temperature sensor, 8, electronic expansion valve, 9, third electronic expansion valve, 10, thin pipe sensor, 11, third thin pipe sensor, 12, evaporator, 13, evaporator middle sensor, 14, indoor environment temperature sensor, 15, third evaporator, 16, third evaporator middle sensor, 17, third indoor environment temperature sensor, 18, thick pipe sensor, 19, third thick pipe sensor, 20, suction temperature sensor, 21, four-way valve.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without inventive effort based on the embodiments of the present invention, are within the scope of the present invention.
As shown in fig. 1, a schematic diagram of a heating control system of an inverter air conditioner with one drive three is shown, assuming that the outdoor unit capacity is 10HP, the first indoor unit capacity is 0.8HP, and the sum of all the indoor unit capacities is equal to 10 HP. An intake air temperature sensor 20 for detecting T intake air is provided on an input pipe of the gas-liquid separator 1 of the compressor 2, the other side of the compressor 2 is provided with an exhaust temperature sensor 3 for detecting T exhaust, the compressor 2 is communicated with a condenser 4 and a gas-liquid separator 1 through a four-way valve, a condenser middle temperature sensor 5 is arranged on the condenser 4, a defrosting sensor 6 is arranged at the outlet of the condenser 4, an outdoor environment temperature sensor 7 is also arranged outside the condenser 4, the other side of the condenser is communicated with an evaporator 12 through an electronic expansion valve 8, a thin tube sensor 10 is arranged between the electronic expansion valve 8 and the evaporator 12, an evaporator middle sensor 13 is arranged on the evaporator 12, an indoor environment temperature sensor 14 is also arranged outside the evaporator 12, and the other side of the evaporator 12 is communicated with a four-way valve 21 through a thick tube sensor 18. The number of the indoor units in fig. 1 is 3, and the indoor units include 3 electronic expansion valves, wherein the third electronic expansion valve 9 is communicated with the third evaporator 15, a third evaporator middle sensor 16 is arranged between the third electronic expansion valve 9 and the third evaporator 15, a third indoor ambient temperature sensor 17 is further arranged outside the third evaporator 15, the other side of the third evaporator 15 is communicated with a four-way valve 21 through a third thick pipe sensor 19, and the second indoor unit also has the same communication structure.
In combination with the above inverter air conditioner, as shown in fig. 3, the present invention discloses a method for controlling a heating electronic expansion valve, comprising the following steps,
s1: firstly, detecting the exhaust superheat degree, and judging whether the exhaust superheat degree is in a proper range, wherein T is1≤TdSH≤T2If yes, then go to step S2; if not, go to S3;
s2: the T is1≤TdSH≤T2The indoor machine control system controls the opening of the electronic expansion valve according to the suction superheat degree, the adjustment of the started expansion valve is determined by the suction superheat degree SH _ HEATING, and the adjustment of the HEATING electronic expansion valve is performed according to PTarget opening degree＝PCurrent opening degreeAdjusting the + delta P, and calculating delta P1;
s3: if the exhaust superheat degree is not suitable when the starting is detectedIf the range of (1) is greater than (TdSH), the determination of TdSH<T1Or TdSH > T2If TdSH > T2Then proceed to S4; if TdSH<T1Then proceed to S5;
s4: if the detected exhaust superheat degree TdSH is more than T2Adjusting the heating electronic expansion valve according to a first control mode of the exhaust superheat degree TdSH, and calculating delta P2;
s5: if the exhaust superheat degree TdSH is detected<T1In accordance with the second control method of the exhaust superheat TdSH, the heating electronic expansion valve is adjusted to calculate Δ P3.
S6: controlling the heating electronic expansion valve to perform delta P regulation operation, wherein when delta P1 is greater than delta P3, the delta P is delta P3; when the delta P1 is less than the delta P2, the delta P is delta P2; otherwise Δ P ═ Δ P1.
In step S2, the suction superheat SH _ superheat is T suction-PS _ TEMP-SHs _ superheat, PS _ TEMP is the saturation temperature of the refrigerant in the system at the low pressure PS of the compressor 2, SHs _ superheat is the target value of the superheat, and SHs _ superheat is the target value of the superheat according to T suctionOuter ringTemperature determination:
outdoor ambient temperature Tao TOuter ring≤-3℃ -3℃＜TOuter ring≤6℃ TOuter ring＞6℃
SHS _ HEATIN degree of superheat of inspiration 2℃ 1℃ 0℃
The Tinspiration is detected by an inspiration temperature sensor 20, PS _ TEMP being the corresponding saturation temperature commonly used in the art, TOuter ringThe temperature is detected by an outdoor ambient temperature sensor 7.
In step S2, the heating electronic expansion valve adjustment operation is performed in accordance with PTarget opening degree＝PCurrent opening degree+ Δ P is adjusted and Δ P1 is valued by the table value (Δ TSH ═ TSH current-TSH previous time)
Figure BDA0001382238570000081
According to the table, the adjusting action delta P1 of the heating electronic expansion valve is related to the current TSH and the delta TSH, the delta P1 increases with the increase of the TSH and increases with the increase of the delta TSH, wherein the current TSH and the previous TSH are calculated by a calculation formula of the degree of superheat of inspiration, and the adjusting step number-5 of the delta P1 is more than or equal to the delta P1 and less than or equal to 6.
Further, when the compressor is operated when the compressor is started and detects that the exhaust superheat degree is not in a proper range, the exhaust pipeline belongs to a high-temperature pipeline, an exhaust temperature sensor 3 and an exhaust pressure sensor are respectively arranged on the exhaust pipeline of each external unit, the exhaust temperature of the exhaust temperature sensor 3 is Texhaust, the exhaust pressure of the exhaust pressure sensor is Pd, even when the compressor is operated at a low temperature, the Texhaust is usually above 30 ℃, and the Ttarget is a target value that the exhaust pipeline needs to adjust the exhaust temperature, wherein the Texhaust superheat degree is T1And T2The exhaust superheat degree TdSH is the difference between the exhaust temperature Td and the saturation temperature Pd _ temp corresponding to the low pressure and the target temperature tfarget that the exhaust line needs to adjust, that is, TdSH is tmouttake-Pd _ temp-T target.
Preferably, in step S4, the first control method of the degree of superheat TdSH of exhaust gas is controlled as follows:
s41: if the temperature is at the target temperature T according to the exhaust superheat degree TdSH2Range operation, i.e. TdSH ═ Texhaust-Pd _ temp-T2Meter for measuringCalculating whether TdSH has reached target T2If not, and TdSH > T2According to the target temperature T2If the control is certain, the heating electronic expansion valve is forbidden to be closed;
s42: after the heating electronic expansion valve is opened for a period of time, whether TdSH reaches the target T or not is calculated2If not, the process returns to S41, and if TdSH reaches the target T2Is controlled in accordance with the range around the target T2Range control of, i.e. giving the target T2Upper and lower limit ranges, upper limit ranges: TdSH > TPIf TdSH is equal to TP(ii) a The lower limit range: TdSH < -TPThen TdSH ═ TP(ii) a Wherein, the steps S41 and S42 are the target temperature T2The value range of the range control is T2-TP～T2+TP；
S43: if TdSH is more than 0.5 ℃ below zero and less than 0.5 ℃, TdSH is 0 ℃, and the current exhaust superheat degree and the target superheat degree T are explained2Close, i.e., stable range;
s44: the slope of the exhaust superheat degree is obtained by the current parameter TdSH and the previous parameter TdSH of the system operation. In particular, i.e. the degree of superheat of the exhaust gas is away from the target T2Is still close to the target T2(ii) a Namely, the value is obtained through a variation trend formula: Δ TdSH — TdSH the previous time.
S45: and (3) giving an upper limit range and a lower limit range of the delta TdSH for system regulation stability, namely when the delta TdSH is calculated to be more than M, the delta TdSH is equal to the value of M, when the delta TdSH is less than-M, the delta TdSH is equal to the value of-M, and when the temperature is more than-0.5 ℃ and less than 0.5 ℃, the opening degree of the current electronic expansion valve is kept at 0 ℃, and no adjustment is made.
S46: by the calculation formula:
Figure BDA0001382238570000101
Figure BDA0001382238570000102
and obtaining the specific regulating step number of the electronic expansion valve.
As calculation example 1, boundary value T of Ttarget of exhaust line2＝42℃，T2Upper limit range value T ofP10 deg.C, target T2The range of (A) is controlled to be 32-52 ℃, the upper limit range M of delta TdSH is 5 ℃, and the maximum valve opening N of the step number of the heating electronic expansion valve is 8 steps;
currently, if tcap is 100 ℃, Pd _ Temp is 47 ℃, TdSH is TdSH-Pd _ Temp-T target, i.e., TdSH is 100 ℃ -47 ℃ -42 ℃ is 11 ℃, TdSH is 11 ℃ > T > T, according to the upper limit of TdSH target given in step S42P，TP＝10℃，TdSH＝10℃；
The former time, T exhaust is 91 ℃, Pd _ Temp is 47 ℃, TdSH the former time is 91-47-42 ℃, TdSH the former time is 2 ℃, TdSH the former time is between the upper limit value and the lower limit value of the target, i.e. TdSH the former time is 2 ℃;
trend values are as follows: Δ TdSH-TdSH previous time, Δ TdSH-10 ℃ -2 ℃ 8 ℃; the upper limit M of Δ TdSH given in step S45 is 5 ℃, then Δ TdSH is 8 ℃ > M, i.e. Δ TdSH is 5 ℃;
then calculating the formula by the delta P2:
Figure BDA0001382238570000103
Figure BDA0001382238570000104
namely, the electronic expansion valve needs to be opened 1.56 steps on the current basis; the temperature of the exhaust gas increases along with the time from the exhaust trend of the figure 2; the exhaust superheat is far away from the target 42 ℃, so that the trend of continuous rising of the exhaust temperature is controlled by opening the large electronic expansion valve in advance, namely the phenomenon that the exhaust superheat gradually increases is controlled.
Further, in step S5, the second control method of the degree of superheat TdSH of exhaust gas is controlled as follows:
s51: if the temperature is at the target temperature T according to the exhaust superheat degree TdSH1Range operation, i.e. TdSH ═ Texhaust-Pd _ Temp-T1(ii) a Calculating whether TdSH reaches target T1If not, and TdSH < T1At the time, according to the target temperature T1Under certain control, the electronic expansion valve is prohibited from openingAn action;
s52: after the heating electronic expansion valve is closed for a period of time, whether TdSH reaches the target T or not is calculated1If not, the process returns to S51, and if TdSH reaches the target T1Is controlled in accordance with the range around the target T1Range control of, i.e. giving the target T1Upper and lower limits of range, TdSH > TqIf TdSH is equal to Tq(ii) a The lower limit range: TdSH < -TqThen TdSH ═ Tq(ii) a Wherein, the target temperature T is obtained in steps S51 and S522The value range of the range control is T1-Tq～T1+Tq；
S53: if TdSH is more than 0.5 ℃ below zero and less than 0.5 ℃, TdSH is 0 ℃, and the current exhaust superheat degree and the target superheat degree T are explained1Close, i.e., stable range;
s54: the slope of the exhaust superheat degree is obtained by the current parameter TdSH and the previous time of the previous parameter TdSH of the system operation, namely the exhaust superheat degree is far away from the target T1Is still close to the target T1(ii) a Namely, the value is obtained through a variation trend formula: Δ TdSH — TdSH the previous time.
S55: in order to stabilize the system regulation, the upper limit and the lower limit of Δ TdSH are given, that is, when Δ TdSH > R is calculated, Δ TdSH ═ R takes a value, when Δ TdSH < -R, Δ TdSH ═ R takes a value, and when Δ TdSH ℃ < Δ TdSH < 0.5 ℃, Δ TdSH ═ 0 ℃ is kept, that is, the current opening of the electronic expansion valve is kept, and no adjustment is made.
S56: by the calculation formula:
Figure BDA0001382238570000111
Figure BDA0001382238570000112
and obtaining the specific regulating step number of the electronic expansion valve.
As an example, the boundary value T of the T target of the exhaust line1＝18℃，T1Upper limit range T ofq10 deg.C, target T1The range of the temperature difference is controlled to be 8-28 ℃, the upper limit range R of delta TdSH is 5 ℃, and the maximum valve opening S of the step number of the heating electronic expansion valve is 8 steps;
in a specific calculation example, as in the calculation example 1, when the exhaust superheat degree is found to be in a downward trend with time, the opening degree of the electronic expansion valve is reduced in advance through a calculation formula, so that the exhaust superheat degree is kept in the range of 18 +/-0.5 for operation.
According to the target control method of the heating electronic expansion valve, the reliability of the compressor can be ensured in the control range of the exhaust superheat degree by ensuring that the exhaust superheat degree is 42 ℃ at the upper limit and 18 ℃ at the lower limit in the whole operation process.
The control method of the heating electronic expansion valve comprises the control of a plurality of targets, and the technical problem to be solved is to realize the simultaneous control of the suction superheat degree and the exhaust superheat degree through one component, control a plurality of target temperatures through one electronic expansion valve component, and control the suction superheat degree of an outdoor heat exchanger and the exhaust superheat degree of an outdoor compressor, so that the continuous heat supply of an indoor unit is ensured, the reliability of the outdoor compressor is also ensured, the normal operation of the whole system is ensured, and the service life is prolonged.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.

Claims (6)

1. A control method for a heating electronic expansion valve is characterized by comprising the following steps: it comprises the following steps:
s1: firstly, detecting the exhaust superheat degree, and judging whether the exhaust superheat degree TdSH is in a proper range or not, wherein T is1≤TdSH≤T2If yes, then go to step S2; if not, go to S3;
s2: the T is1≤TdSH≤T2The control system of the indoor unit controls the opening of the electronic expansion valve according to the suction superheat degree, the adjustment of the started expansion valve is determined by the suction superheat degree SH _ HEATING, and the adjustment of the HEATING electronic expansion valve is performed according to PTarget opening degree＝PCurrent opening degreeAdjusting the + delta P to obtain delta P1, wherein the adjustment step number-5 of the delta P1 is more than or equal to the delta P1 is more than or equal to 6;
s3: if the starting detects that the exhaust superheat degree is not in the proper range, the TdSH is judged<T1Or TdSH > T2If TdSH > T2Then proceed to S4; if TdSH<T1Then proceed to S5;
s4: if the detected exhaust superheat degree TdSH is more than T2Adjusting the heating electronic expansion valve according to a first control mode of the exhaust superheat degree TdSH, and calculating delta P2;
s5: if the exhaust superheat degree TdSH is detected<T1Adjusting the heating electronic expansion valve according to a second control mode of the exhaust superheat degree TdSH to calculate delta P3;
s6: controlling the heating electronic expansion valve to perform delta P regulation operation, wherein when delta P1 is greater than delta P3, the delta P is delta P3; when the delta P1 is less than the delta P2, the delta P is delta P2; otherwise Δ P ═ Δ P1;
in step S4, the first control method of the exhaust superheat TdSH is as follows:
s41: if the temperature is at the target temperature T according to the exhaust superheat degree TdSH2Range operation, i.e. TdSH ═ Texhaust-Pd _ temp-T2Calculating whether TdSH reaches the target T2If not, and TdSH > T2If yes, the heating electronic expansion valve is forbidden to be closed;
s42: after the heating electronic expansion valve is opened for a period of time, whether TdSH reaches the target T or not is calculated2If not, the process returns to S41, and if TdSH reaches the target T2Is controlled in accordance with the range around the target T2To the target T2Upper and lower limit ranges, upper limit ranges: TdSH > TPIf TdSH is equal to TP(ii) a The lower limit range: TdSH < -TPThen TdSH ═ TP；
S43: if TdSH is more than 0.5 ℃ and less than 0.5 ℃, the TdSH is equal to 0 ℃;
s44: obtaining the exhaust superheat slope by the system operation of the current parameter TdSH and the previous time of the previous parameter TdSH, and calculating delta TdSH as TdSH-TdSH previous time;
s45: giving an upper limit range and a lower limit range of the delta TdSH, namely when the delta TdSH is calculated to be more than M, the delta TdSH is equal to the value of M, when the delta TdSH is less than-M, the delta TdSH is equal to the value of-M, and when the temperature is more than-0.5 ℃ and less than the temperature is less than the temperature of 0.5 ℃, the opening degree of the current electronic expansion valve is kept, and no adjustment is made;
s46: by the calculation formula:
Figure FDA0002932474000000021
Figure FDA0002932474000000022
obtaining the specific electronic expansion valve regulating step number delta P2;
in step S5, the second control method of the degree of superheat TdSH of exhaust gas is as follows:
s51: if the temperature is at the target temperature T according to the exhaust superheat degree TdSH1Range operation, i.e. TdSH ═ Texhaust-Pd _ Temp-T1(ii) a Calculating whether TdSH reaches target T1If not, and TdSH < T1When the electronic expansion valve is opened, the electronic expansion valve is prohibited to act;
s52: after the heating electronic expansion valve is closed for a period of time, whether TdSH reaches the target T or not is calculated1If not, the process returns to S51, and if TdSH reaches the target T1Is controlled in accordance with the range around the target T1To the target T1Upper and lower limits of range, TdSH > TqIf TdSH is equal to Tq(ii) a The lower limit range: TdSH < -TqThen TdSH ═ Tq；
S53: if TdSH is more than 0.5 ℃ and less than 0.5 ℃, the TdSH is equal to 0 ℃;
s54: obtaining the exhaust superheat slope by the system operation of the current parameter TdSH and the previous time of the previous parameter TdSH, and calculating delta TdSH as TdSH-TdSH previous time;
s55: giving an upper limit range and a lower limit range of the delta TdSH, namely when the delta TdSH is calculated to be more than R, the delta TdSH is equal to R, when the delta TdSH is less than-R, the delta TdSH is equal to-R, and when the temperature is more than-0.5 ℃ and is less than the temperature of 0.5 ℃, the delta TdSH is equal to 0 ℃, the opening degree of the current electronic expansion valve is kept, and no adjustment is made;
s56: tong (Chinese character of 'tong')The over-calculation formula:
Figure FDA0002932474000000031
Figure FDA0002932474000000032
obtaining the specific regulating step number of the electronic expansion valve;
wherein Pd _ temp is the saturation temperature corresponding to the low pressure Pd of the compressor, TPThe preset value of the upper limit range of the exhaust superheat TdSH under a first control mode, M is the preset value of the upper limit range of delta TdSH under the first control mode, N is the maximum valve opening of the heating electronic expansion valve adjusting step number under the first control mode, and T is the maximum valve opening of the heating electronic expansion valve adjusting step number under the first control modeqThe preset value of the upper limit range of the exhaust superheat TdSH in the second control mode is shown, R is the preset value of the upper limit range of delta TdSH in the second control mode, and S is the maximum valve opening of the heating electronic expansion valve in the step number in the second control mode.
2. A control method for a thermal electronic expansion valve according to claim 1, wherein: in step S2, the degree of superheat SH _ superheat is T intake-PS _ TEMP-SHs _ superheat, which is a target value of the degree of superheat SHs _ superheat based on TOuter ringThe temperature is determined, wherein PS _ TEMP is the saturation temperature of the refrigerant at the low pressure PS of the compressor.
3. A method of controlling a thermionic expansion valve as claimed in claim 2, wherein: when T isOuter ringThe target value SHS _ HEATING of the superheat degree is equal to or less than-3 ℃, and the target value SHS _ HEATING is equal to 2 ℃; when the temperature is lower than-3 ℃ and lower than TOuter ringThe target value SHS _ HEATING of the superheat degree is equal to or less than 6 ℃, and the target value SHS _ HEATING of the superheat degree is equal to 1 ℃; when T isOuter ringWhen the temperature is higher than 6 ℃, the target superheat value SHS _ heatingis 0 ℃.
4. A control method for a thermal electronic expansion valve according to claim 1, wherein: the heating electronic expansion valve regulating action delta P1 is related to TSH current and delta TSH, the delta P1 increases with the increase of TSH, and the delta TSH increases with the increase of delta TSH, wherein TSH is a calculated value of suction superheat degree, and the delta TSH is the TSH current time and the TSH previous time.
5. A control method for a thermal electronic expansion valve according to claim 1, wherein: boundary value T of T target of exhaust pipeline2＝42℃，T2Upper limit range value T ofP10 ℃ target T2The range of (A) is controlled to be 32-52 ℃, the upper limit range M of delta TdSH is 5 ℃, and the maximum valve opening N of the heating electronic expansion valve adjusting step number is 8 steps.
6. A control method for a thermal electronic expansion valve according to claim 1, wherein: boundary value T of T target of exhaust pipeline1＝18℃，T1Upper limit range T ofq10 deg.C, target T1The range of (A) is controlled to be 8-28 ℃, the upper limit range R of delta TdSH is 5 ℃, and the maximum valve opening S of the heating electronic expansion valve adjusting step number is 8 steps.
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