Electronic expansion valve control method and device for heat pump system and low-temperature air source heat pump

Abstract

The present invention discloses an electronic expansion valve control method and device for a heat pump system and a low-temperature air source heat pump. The electronic expansion valve control method comprises the following steps: step S1, after the heat pump unit is started, the machine is turned on and operated, and a controller collects parameters; step S2, the first electronic expansion valve is automatically operated and adjusted according to the pid; step S3, a first-level judgment condition is performed; step S4, a second-level judgment condition is performed simultaneously, and according to the judgment condition, it is determined that the first electronic expansion valve has a small range fluctuation or a large step number fluctuation trend, and stability adjustment is started; or according to the second-level judgment condition, the original control mode of the heat pump system is maintained to automatically operate; the system parameter control that requires high stability in certain use occasions is solved, and the system instability problem caused by fluctuations in system temperature, power and other parameters due to fluctuations in electronic expansion valve regulation is avoided.

Description

[Technical field]

[0001] The present invention relates to a low-temperature air source heat pump control technology, and in particular to an electronic expansion valve control method and device for a heat pump system and a low-temperature air source heat pump. [Background technology]

[0002] As an energy-saving technology, heat pumps have received widespread attention from countries around the world. Air source heat pumps can absorb abundant low-grade energy from the ambient atmosphere. They are easy to use and have low installation costs. Therefore, air source heat pumps have become the most widely used type of heat pumps.

[0003] When working, the air source heat pump device usually uses temperature sensors to collect parameters such as the suction temperature and exhaust temperature of the heat pump system, and controls the opening of the electronic expansion valve to control the refrigerant circulation volume of the heat pump system.

[0004] When used in a low-temperature environment, the electronic expansion valve controls the opening according to temperature conditions such as superheat. Due to the large hysteresis and obvious damping characteristics of the refrigerant circulation of the heat pump system, it is particularly easy for the opening of the electronic expansion valve to be repeatedly over-adjusted and fluctuated in low ambient temperature and high water temperature scenarios. At this time, due to the large diameter of the pre-selected electronic expansion valve, the same opening change will have a great impact on the entire system, causing system fluctuations. In addition, unstable refrigerant quantity regulation will affect the temperature control stability of the system, and long-term fluctuations will affect the reliability of the heat pump device; especially during the startup process, the exhaust temperature oscillates and fluctuates, which will cause the reliability of the entire system to deteriorate. [Summary of the invention]

[0005] The present invention provides an electronic expansion valve control method and device for a heat pump system, and a low-temperature air source heat pump. The method and device automatically adjust the rate of change of the fluctuation step number within a cycle of the electronic expansion valve to solve the problem of high-stability system parameter control required for the low-temperature air source heat pump in certain usage scenarios, and avoid system instability caused by fluctuations in system parameters such as temperature and power due to fluctuations in electronic expansion valve regulation.

[0006] The technical solution adopted by the present invention to solve its technical problem is:

[0007] A method for controlling an electronic expansion valve of a heat pump system, the heat pump system comprising a first heat exchanger arranged outdoors, a second heat exchanger using a water pump unit for water cooling and heat exchange, a compressor, a third heat exchanger for replenishing air to the compressor, a first electronic expansion valve arranged between the first heat exchanger and the third heat exchanger, and a second electronic expansion valve arranged between the third heat exchanger and the second heat exchanger, the compressor being connected between the first heat exchanger and the second heat exchanger through a refrigerant pipeline and a four-way valve; the method for controlling the electronic expansion valve comprising the following steps:

[0008] Step S1, the heat pump unit is started and operated, and the controller collects parameters after the compressor starts and operates for a period of time;

[0009] The parameters collected by the controller include:

[0010] The maximum fluctuation step number B of the first electronic expansion valve is collected during this period 大N ;

[0011] This cycle collects the minimum fluctuation step number B of the first electronic expansion valve 小N ;

[0012] The maximum fluctuation step number B of the first electronic expansion valve is collected during this period 大N Time t 大N ;

[0013] This cycle collects the minimum fluctuation step number B of the first electronic expansion valve 小N Time t 小N ;

[0014] The maximum fluctuation step number B of the first electronic expansion valve is collected during this period 大N Superheat parameter P at the moment 大N ;

[0015] This cycle collects the minimum fluctuation step number B of the first electronic expansion valve 小N Superheat parameter P at the moment 小N ;

[0016] The maximum fluctuation step number B of the first electronic expansion valve collected in the last fluctuation cycle 大N-1 ;

[0017] The minimum fluctuation step number B of the first electronic expansion valve collected in the last fluctuation cycle 小N-1 ;

[0018] The maximum fluctuation step number B of the first electronic expansion valve collected in the last fluctuation cycle 大N-1 Time t 大N-1 ;

[0019] The minimum fluctuation step number B of the first electronic expansion valve collected in the last fluctuation cycle 小N-1 Time t small N-1 ;

[0020] The maximum fluctuation step number B of the first electronic expansion valve collected in the last fluctuation cycle 大N-1 Superheat parameter P at the moment 大N-1 ;

[0021] The minimum fluctuation step number B of the first electronic expansion valve collected in the last fluctuation cycle 小N-1 Superheat parameter P at the moment 小N-1 ;

[0022] Among them, this cycle refers to the process of the first electronic expansion valve from the maximum opening to the minimum opening, or the process of the first electronic expansion valve from the minimum opening to the maximum opening, which is collected by the controller. This cycle is identified by the controller automatically calculating the number of actions of the first electronic expansion valve; and according to the hysteresis of the controller controlling the heat pump system, the control process generally satisfies the following rules: the maximum opening of the first electronic expansion valve in the next cycle ≤ the maximum opening of the first electronic expansion valve in this cycle, and the minimum opening of the first electronic expansion valve in the next cycle ≥ the minimum opening of the first electronic expansion valve in this cycle;

[0023] Step S2, the first electronic expansion valve automatically operates and adjusts according to pid

[0024] The compressor and the first electronic expansion valve are automatically adjusted according to the corresponding PID control conditions. When the compressor runs stably, the first electronic expansion valve performs stability adjustment according to the following judgment;

[0025] Step S3, performing a first-level determination condition;

[0026] When the first electronic expansion valve fluctuates, the number of positive and negative actions B (N) The absolute value of |B (N) |≤b1, it means that the first electronic expansion valve is oscillating around the target value;

[0027] Otherwise, the process returns to step S2 in which the first electronic expansion valve automatically operates and adjusts according to the pid control condition;

[0028] Step S4, synchronously perform the secondary determination conditions;

[0029] When the first electronic expansion valve oscillates around the target value, the following actions are performed in sequence:

[0030] When the first electronic expansion valve does not oscillate around the target value, the process directly returns to step S2;

[0031] Step S4.1.1, when the number of positive and negative actions of the first electronic expansion valve fluctuation step number C( N) The absolute value of |C (N) |≤|a

(t 大N-1 -t 大N )+(t 小N-1 -t 小N )

[0032] Step S4.1.2: At this time, the adjustment speed of the first electronic expansion valve will be slowed down to the preset initial adjustment period V a , and the first electronic expansion valve can adjust at most W1 steps each time;

[0033] Step S4.1.3, run V a After a certain time, check whether the superheat deviation is within the fitted target superheat value range of the ambient temperature and water temperature;

[0034] When |P 实际过热度 -P 目标过热度 |< 过 The upper limit of heat deviation and superheat deviation is based on D*T h 2 +E*T s 2 +F*T h +G*T s +H formula, the regulation rate of the first electronic expansion valve is affected by the superheat change rate to perform regulation cycle correction; this is superheat target identification, the heat pump system can improve reliability when operating within a suitable superheat range, the superheat fitting value is calculated by the formula of the superheat deviation upper limit value, and the ambient temperature value and water temperature value are associated here;

[0035] When |P 实际过热度 -P 目过热度 |If it is not within the above-mentioned limited range, return to step S4.1.2 for re-determination;

[0036] Step S4.1.4: The first electronic expansion valve adjusts the cycle V j =V j-1 *K is adjusted and corrected, and then the first electronic expansion valve is adjusted according to V j The first electronic expansion valve is adjusted at a maximum of W2 steps each time; wherein, when V is calculated for the first time in this step, j-1 =V a , P i Indicates V j-1 The real-time superheat parameter collected by the controller after time, P j-1 Indicates V j-1 The real-time superheat parameter collected by the controller at time; moreover, the following conditions must be met in this step:

[0037] ①When (P j -P j-1 ) / V j-1 >V1, k=1+

(P 大N-1 -P 小N-1 ) / (t 大N-1 -t 小N-1 )

(P 大N -P 小N ) / (t 大N -t 小N )

[0038] ②When V2<(P j -P j-1) / V j-1 ≤V1, k=k1;

[0039] ③When V3<(P j -P j-1 ) / V j-1 When ≤V2, k=k2;

[0040] ④When V4<(P j -P j-1 ) / V j-1 ≤V3, k=k3;

[0041] ⑤When (P j -P j-1 ) / V j-1 When ≤V4, k=k4;

[0042] Step S4.2.1, |a

(t 大N-1 -t 大N )+(t 小N-1 -t 小N )

(t 大N-1 -t 大N )+(t 小N-1 -t 小N )

[0043] Step S4.2.2: At this time, the adjustment speed of the first electronic expansion valve will be slowed down to the preset initial adjustment period V b , and the expansion valve can be adjusted by a maximum of W1 steps each time;

[0044] Step S4.2.3, run V b After a certain period of time, detect the deviation range of superheat;

[0045] When |P 实际过热度 -P 目标过热度 |<D*T h 2 +E*T s 2 +F*T h +G*T s +H, the regulation rate of the first electronic expansion valve is affected by the superheat change rate and the regulation cycle is corrected;

[0046] When |P 实际过热度 -P 目标过热度 |If it is not within the above-mentioned limited range, return to step S4.2.2 for re-determination;

[0047] Step S4.2.4: The first electronic expansion valve adjusts the cycle Vj=V j -11*k is adjusted and corrected, and then the first electronic expansion valve is adjusted according to V j The first electronic expansion valve is regulated in an adjustment cycle, and the first electronic expansion valve is adjusted by a maximum of W2 steps each time; wherein, when V is calculated for the first time in this step j-1 =V b , P j Indicates V j-1 The real-time superheat parameter collected by the controller after time, P j-1 Indicates V j-1 The real-time superheat parameter collected by the controller at time; moreover, the following conditions must be met in this step:

[0048] ⑥When (P j -P j-1 ) / V j-1 >V1, k=1+

(P 大N-1 -P 小N-1 ) / (t 大N-1 -t 小N-1 )

(P 大N -P 小N ) / (t 大N -t 小N )

[0049] ⑦When V2<(P j -P j-1 ) / V j-1 When ≤V1, k=k5;

[0050] ⑧When V3<(P j -P j-1 ) / V j-1 When ≤V2, k=k6;

[0051] ⑨When V4<(P j -P j-1 ) / V j-1 When ≤V3, k=k7;

[0052] ⑩When (P j -P j-1 ) / V j-1 When ≤V4, k=k8;

[0053] Step S4.3, when the first electronic expansion valve fluctuates in the positive and negative actions C (N) Absolute value of times|C (N) |>|a

(t 大N-1 -t 大N )+(t 小N-1 -t 小N)

[0054] The parameters in the description of all the above steps are as follows:

[0055] B (N) Indicates the number of times the first electronic expansion valve is operated collected by the controller;

[0056] C (N) Indicates the number of times the first electronic expansion valve is operated collected by the controller;

[0057] a is the positive coefficient;

[0058] b1 is the volatility coefficient;

[0059] b2 is the volatility coefficient;

[0060] b3 is the volatility coefficient;

[0061] P 实际过热度 Indicates the actual superheat value collected by the controller;

[0062] T h Indicates the real-time ambient temperature value collected by the controller;

[0063] T s Indicates the real-time water temperature value collected by the controller;

[0064] D is the superheat coefficient;

[0065] E is the superheat coefficient;

[0066] F is the superheat coefficient;

[0067] G is the superheat coefficient;

[0068] H is the superheat coefficient;

[0069] V j To calculate the target valve regulation cycle;

[0070] V j-1 To calculate the target valve regulation cycle of the last sampling;

[0071] V a Initial conditioning cycle;

[0072] V b Initial conditioning cycle;

[0073] V1 is the valve regulation cycle time boundary value;

[0074] V2 is the valve regulation cycle time boundary value;

[0075] V3 is the valve regulation cycle time boundary value;

[0076] V4 is the valve regulation cycle time boundary value;

[0077] W1 is the number of valve adjustment steps;

[0078] W2 is the number of valve adjustment steps;

[0079] K is the superheat coefficient;

[0080] K1 is the valve regulating cycle coefficient;

[0081] K2 is the valve regulating cycle coefficient;

[0082] K3 is the valve regulating cycle coefficient;

[0083] K4 is the valve regulating cycle coefficient;

[0084] K5 is the valve regulating cycle coefficient;

[0085] K6 is the valve regulating cycle coefficient;

[0086] K7 is the valve regulating cycle coefficient;

[0087] K8 is the valve regulating cycle coefficient.

[0088] Furthermore, it also includes:

[0089] a is the positive coefficient, and the optimal value is 0.5;

[0090] b1 is the volatility coefficient, and the optimal value is 15;

[0091] b2 is the volatility coefficient, and the optimal value is 5;

[0092] b3 is the volatility coefficient, and the optimal value is 7;

[0093] D is the superheat coefficient, and the optimal value is 0.006;

[0094] E is the superheat coefficient, and the optimal value is 0.002;

[0095] F is the superheat coefficient, the optimal value is 0.015;

[0096] G is the superheat coefficient, and the optimal value is 0.001;

[0097] H is the superheat coefficient, and the optimal value is 1.2;

[0098] V a Initial adjustment period, and the optimal value is 120s;

[0099] V b Initial adjustment period, and the optimal value is 180s;

[0100] V1 is the boundary value of the valve regulating cycle time, and the optimal value is 0.5℃ / min;

[0101] V2 is the boundary value of the valve regulating cycle time, and the optimal value is 0.4℃ / min;

[0102] V3 is the boundary value of the valve regulating cycle time, and the optimal value is 0.3℃ / min;

[0103] V4 is the boundary value of the valve regulation cycle time, and the optimal value is 0.2℃ / min;

[0104] W1 is the number of valve adjustment steps, and the optimal value is 2;

[0105] W2 is the number of valve adjustment steps, and the optimal value is 1;

[0106] K1 is the valve regulating cycle coefficient, and the optimal value is 1.3;

[0107] K2 is the valve regulating cycle coefficient, and the optimal value is 1.2;

[0108] K3 is the valve regulating cycle coefficient, and the optimal value is 1.1;

[0109] K4 is the valve regulating cycle coefficient, and the optimal value is 1;

[0110] K5 is the valve regulating cycle coefficient, and the optimal value is 1.5;

[0111] K6 is the valve regulating cycle coefficient, and the optimal value is 1.4;

[0112] K7 is the valve regulating cycle coefficient, and the optimal value is 1.2;

[0113] K8 is the valve regulation cycle coefficient, and the optimal value is 1.

[0114] A control device for a heat pump system, comprising:

[0115] Memory; and

[0116] A processor coupled to the memory is configured to execute any one of the above-mentioned methods for controlling an electronic expansion valve of a heat pump system based on instructions stored in the memory.

[0117] A low-temperature air source heat pump, comprising:

[0118] A heat pump system; and a control device for a heat pump system according to the above.

[0119] A computer-readable storage medium includes computer program instructions, wherein the computer program instructions, when executed by a processor, implement any one of the above-mentioned electronic expansion valve control methods for a heat pump system.

[0120] The beneficial effects of the present invention are:

[0121] By automatically adjusting the rate of change of the fluctuation steps within the electronic expansion valve cycle, the system stability can be achieved faster than the traditional expansion valve adjustment process, and the adjustment rate of the valve is controlled according to the system superheat state, taking into account the high reliability operation of the system; it can effectively solve the problem of unstable system operation of low-temperature air source heat pumps in low ambient temperature and high water temperature scenarios, and achieve high-stability system parameter control by optimizing the adjustment rate of the electronic expansion valve, avoiding system instability caused by fluctuations in system temperature, power and other parameters due to fluctuations in electronic expansion valve adjustment.

Brief Description of the Drawings

[0122] Figure 1 It is a schematic diagram of the working principle of the heat pump system of the present invention;

[0123] Figure 2 It is a flow chart of the electronic expansion valve control method in the present invention. [Specific implementation method]

[0124] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0125] The performance of low-temperature air source heat pumps is greatly affected by the ambient temperature, especially in places with very low ambient temperature in winter. When heating higher water temperatures (such as above 60°C), the efficiency of low-temperature air source heat pumps is low. In related technologies, a compression system including a two-stage electronic expansion valve can be used to improve the efficiency of low-temperature air source heat pumps.

[0126] Figure 1 It is a schematic diagram of the structure of a heat pump system according to some embodiments disclosed in the present invention.

[0127] like Figure 1 As shown, the heat pump system includes a first heat exchanger 1 arranged outdoors, a second heat exchanger 2 using a water pump unit for water cooling and heat exchange, a compressor 3, a third heat exchanger 4 for replenishing air to the compressor 3, a first electronic expansion valve 5 arranged between the first heat exchanger 1 and the third heat exchanger 4, and a second electronic expansion valve 6 arranged between the third heat exchanger 4 and the second heat exchanger 2. The compressor 3 is connected between the first heat exchanger 1 and the second heat exchanger 2 through a refrigerant pipeline and a four-way valve 7. In addition, Figure 1In the figure, port C of the four-way valve 7 is connected to the second heat exchanger 2, port D is connected to the air outlet of the compressor 3, port E is connected to the air supply port of the compressor 3 via the first heat exchanger 1 and the third heat exchanger 4, and port S is connected to the air inlet of the compressor 3.

[0128] The present invention discloses an electronic expansion valve control method for a heat pump system provided by some embodiments, such as Figure 2 As shown, the specific implementation method includes the following steps:

[0129] Step S1, the heat pump unit is started and operated, and the controller collects parameters after the compressor starts and operates for a period of time;

[0130] The parameters collected by the controller include:

[0131] The maximum fluctuation step number B of the first electronic expansion valve is collected during this period 大N ;

[0132] This cycle collects the minimum fluctuation step number B of the first electronic expansion valve 小N ;

[0133] The maximum fluctuation step number B of the first electronic expansion valve is collected during this period 大N Time t 大N ;

[0134] This cycle collects the minimum fluctuation step number B of the first electronic expansion valve 小N Time t 小N ;

[0135] The maximum fluctuation step number B of the first electronic expansion valve is collected during this period 大N Superheat parameter P at the moment 大N ;

[0136] This cycle collects the minimum fluctuation step number B of the first electronic expansion valve 小N Superheat parameter P at the moment 小N ;

[0137] The maximum fluctuation step number B of the first electronic expansion valve collected in the last fluctuation cycle 大N-1 ;

[0138] The minimum fluctuation step number B of the first electronic expansion valve collected in the last fluctuation cycle 小N-1 ;

[0139] The maximum fluctuation step number B of the first electronic expansion valve collected in the last fluctuation cycle 大N-1 Time t 大N-1 ;

[0140] The minimum fluctuation step number B of the first electronic expansion valve collected in the last fluctuation cycle 小N-1 Time t small N-1 ;

[0141] The maximum fluctuation step number B of the first electronic expansion valve collected in the last fluctuation cycle 大N-1 Superheat parameter P at the moment 大N-1 ;

[0142] The minimum fluctuation step number B of the first electronic expansion valve collected in the last fluctuation cycle 小N-1 Superheat parameter P at the moment 小N-1 ;

[0143] Among them, this cycle refers to the process of the first electronic expansion valve from the maximum opening to the minimum opening, or the process of the first electronic expansion valve from the minimum opening to the maximum opening, which is collected by the controller. This cycle is identified by the controller automatically calculating the number of actions of the first electronic expansion valve; and according to the hysteresis of the controller controlling the heat pump system, the control process generally satisfies the following rules: the maximum opening of the first electronic expansion valve in the next cycle ≤ the maximum opening of the first electronic expansion valve in this cycle, and the minimum opening of the first electronic expansion valve in the next cycle ≥ the minimum opening of the first electronic expansion valve in this cycle;

[0144] Step S2, the first electronic expansion valve automatically operates and adjusts according to pid

[0145] The compressor and the first electronic expansion valve are automatically adjusted according to the corresponding PID control conditions. When the compressor runs stably, the first electronic expansion valve performs stability adjustment according to the following judgment;

[0146] Step S3, performing a first-level determination condition;

[0147] When the first electronic expansion valve fluctuates, the number of positive and negative actions B (N) The absolute value of |B (N) |≤b1, it means that the first electronic expansion valve is oscillating around the target value;

[0148] Otherwise, the process returns to step S2 in which the first electronic expansion valve automatically operates and adjusts according to the pid control condition;

[0149] Step S4, synchronously perform the secondary determination conditions;

[0150] When the first electronic expansion valve oscillates around the target value, the following actions are performed in sequence:

[0151] When the first electronic expansion valve does not oscillate around the target value, the process directly returns to step S2;

[0152] According to the judgment conditions, it is determined that the first electronic expansion valve is fluctuating in a small range or a large step number, and stability adjustment is started; or according to the secondary judgment conditions, the original control mode of the heat pump system is maintained to automatically operate;

[0153] Step S4.1.1, when the number of positive and negative actions of the first electronic expansion valve fluctuation step number C (N) The absolute value of |C (N) |≤|a

(t 大N-1 -t 大N )+(t 小N-1 -t 小N )

[0154] Step S4.1.2: At this time, the adjustment speed of the first electronic expansion valve will be slowed down to the preset initial adjustment period V a , and the first electronic expansion valve can adjust at most W1 steps each time;

[0155] Step S4.1.3, run V a After a certain time, check whether the superheat deviation is within the fitted target superheat value range of the ambient temperature and water temperature;

[0156] When |P 实际过热度 -P 目标过热度 |<Superheat deviation upper limit value, superheat deviation upper limit value is based on D*T h 2 +E*T s 2 +F*T h +G*T s +H formula, the regulation rate of the first electronic expansion valve is affected by the superheat change rate to perform regulation cycle correction; this is superheat target identification, the heat pump system can improve reliability when operating within a suitable superheat range, the superheat fitting value is calculated by the formula of the superheat deviation upper limit value, and the ambient temperature value and water temperature value are associated here;

[0157] When |P 实际过热度 -P 目过热度 |If it is not within the above-mentioned limited range, return to step S4.1.2 for re-determination;

[0158] Step S4.1.4: The first electronic expansion valve adjusts the cycle V j =V j-1 *K is adjusted and corrected, and then the first electronic expansion valve is adjusted according to V j The first electronic expansion valve is adjusted at a maximum of W2 steps each time; wherein, when V is calculated for the first time in this step, j-1 =V a , P j Indicates V j-1 The real-time superheat parameter collected by the controller after time, P j-1 Indicates V j-1The real-time superheat parameter collected by the controller at time; moreover, the following conditions must be met in this step:

[0159] ①When (P j -P j-1 ) / V j-1 >V1, k=1+

(P 大N-1 -P 小N-1 ) / (t 大N-1 -t 小N-1 )

(P 大N -P 小N ) / (t 大N -t 小N )

[0160] ②When V2<(P j -P j-1 ) / V j-1 ≤V1, k=k1;

[0161] ③When V3<(P j -P j-1 ) / V j-1 When ≤V2, k=k2;

[0162] ④When V4<(P j -P j-1 ) / V j-1 ≤V3, k=k3;

[0163] ⑤When (P j -P j-1 ) / V j-1 When ≤V4, k=k4;

[0164] Step S4.2.1, |a

(t 大N-1 -t 大N )+(t 小N-1 -t 小N )

(t 大N-1 -t 大N )+(t 小N-1 -t 小N )

[0165] Step S4.2.2: At this time, the adjustment speed of the first electronic expansion valve will be slowed down to the preset initial adjustment period V b , and the expansion valve can be adjusted by a maximum of W1 steps each time;

[0166] Step S4.2.3, run Vb After a certain period of time, detect the deviation range of superheat;

[0167] When |P 实际过热度 -P 目标过热度 |<D*T h 2 +E*T s 2 +F*T h +G*T s +H, the regulation rate of the first electronic expansion valve is affected by the superheat change rate and the regulation cycle is corrected;

[0168] When |P 实际过热度 -P 目过热度 |If it is not within the above-mentioned limited range, return to step S4.2.2 for re-determination;

[0169] Step S4.2.4: The first electronic expansion valve adjusts the cycle V j =V j-1 *k is adjusted and corrected, and then the first electronic expansion valve is adjusted according to V j The first electronic expansion valve is regulated in an adjustment cycle, and the first electronic expansion valve is adjusted by a maximum of W2 steps each time; wherein, when V is calculated for the first time in this step j-1 =V b , P j Indicates V j-1 The real-time superheat parameter collected by the controller after time, P j-1 Indicates V j-1 The real-time superheat parameter collected by the controller at time; moreover, the following conditions must be met in this step:

[0170] ⑥When (P j -P j-1 ) / V j-1 >V1, k=1+

(P 大N-1 -P 小N-1 ) / (t 大N-1 -t 小N-1 )

(P 大N -P 小N ) / (t 大N -t 小N )

[0171] ⑦When V2<(P j -P j-1 ) / V j-1 When ≤V1, k=k5;

[0172] ⑧When V3<(P j -P j-1 ) / V j-1 When ≤V2, k=k6;

[0173] ⑨When V4<(P j -P j-1 ) / V j-1 When ≤V3, k=k7;

[0174] ⑩When (P j -P j-1 ) / V j-1 When ≤V4, k=k8;

[0175] Step S4.3, when the first electronic expansion valve fluctuates in the positive and negative actions C (N) Absolute value of times|C (N) |>|a

(t 大N-1 -t 大N )+(t 小N-1 -t 小N )

[0176] The parameters in the description of all the above steps are as follows:

[0177] B (N) Indicates the number of times the first electronic expansion valve is operated collected by the controller;

[0178] C (N) Indicates the number of times the first electronic expansion valve is operated collected by the controller;

[0179] a is the positive coefficient, and the optimal value is 0.5;

[0180] b1 is the volatility coefficient, and the optimal value is 15;

[0181] b2 is the volatility coefficient, and the optimal value is 5;

[0182] b3 is the volatility coefficient, and the optimal value is 7;

[0183] P 实际过热度 Indicates the actual superheat value collected by the controller;

[0184] T h Indicates the real-time ambient temperature value collected by the controller;

[0185] T s Indicates the real-time water temperature value collected by the controller;

[0186] D is the superheat coefficient, and the optimal value is 0.006;

[0187] E is the superheat coefficient, and the optimal value is 0.002;

[0188] F is the superheat coefficient, the optimal value is 0.015;

[0189] G is the superheat coefficient, and the optimal value is 0.001;

[0190] H is the superheat coefficient, and the optimal value is 1.2;

[0191] V a Initial adjustment period, and the optimal value is 120s;

[0192] V b Initial adjustment period, and the optimal value is 180s;

[0193] V1 is the boundary value of the valve regulating cycle time, and the optimal value is 0.5℃ / min;

[0194] V2 is the boundary value of the valve regulating cycle time, and the optimal value is 0.4℃ / min;

[0195] V3 is the boundary value of the valve regulating cycle time, and the optimal value is 0.3℃ / min;

[0196] V4 is the boundary value of the valve regulation cycle time, and the optimal value is 0.2℃ / min;

[0197] W1 is the number of valve adjustment steps, and the optimal value is 2;

[0198] W2 is the number of valve adjustment steps, and the optimal value is 1;

[0199] K1 is the valve regulating cycle coefficient, and the optimal value is 1.3;

[0200] K2 is the valve regulating cycle coefficient, and the optimal value is 1.2;

[0201] K3 is the valve regulating cycle coefficient, and the optimal value is 1.1;

[0202] K4 is the valve regulating cycle coefficient, and the optimal value is 1;

[0203] K5 is the valve regulating cycle coefficient, and the optimal value is 1.5;

[0204] K6 is the valve regulating cycle coefficient, and the optimal value is 1.4;

[0205] K7 is the valve regulating cycle coefficient, and the optimal value is 1.2;

[0206] K8 is the valve regulation cycle coefficient, and the optimal value is 1.

[0207] In this embodiment, by optimizing the regulation rate of the electronic expansion valve, system instability problems caused by fluctuations in system parameters such as system temperature and power due to fluctuations in the regulation of the electronic expansion valve are avoided; especially during low-temperature heating operation, by real-time detection of the number of steps of the forward and reverse actions of the electronic expansion valve, changes in system superheat parameters, fitted superheat of the ambient temperature and water temperature and other parameters, the regulation state of the electronic expansion valve is comprehensively judged, and then the action cycle of the electronic expansion valve is determined, thereby avoiding over-regulation of the electronic expansion valve and effectively improving the stability of the system operation.

[0208] In addition, the control device of the heat pump system includes a memory and a processor coupled to the memory, and the processor is configured to execute the method of the above embodiment based on the instructions stored in the memory.

[0209] The memory may include, for example, a system memory, a fixed non-volatile storage medium, etc. The system memory may store, for example, an operating system, an application program, a boot loader, and other programs.

[0210] The control device of the heat pump system may also include an input / output interface, a network interface, a storage interface, etc. These interfaces, as well as the memory and the processor, may be connected, for example, via a bus. The input / output interface provides a connection interface for input / output devices such as a display, a mouse, a keyboard, and a touch screen. The network interface provides a connection interface for various networked devices. The storage interface provides a connection interface for external storage devices such as an SD card and a USB flash drive.

[0211] The embodiments disclosed in the present invention further provide a low-temperature air source heat pump, comprising: a heat pump system and a control device of the heat pump system of the above embodiments.

[0212] The embodiments disclosed in the present invention further provide a computer-readable storage medium, including computer program instructions, which, when executed by a processor, implement the electronic expansion valve control method of the heat pump system of any of the above embodiments.

[0213] So far, the embodiments disclosed in the present invention have been described in detail. In order to avoid obscuring the concept of the present invention, some details known in the art are not described. Based on the above description, those skilled in the art can fully understand how to implement the technical solution disclosed here.

[0214] Those skilled in the art will appreciate that the embodiments disclosed in the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may be disclosed in the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may be disclosed in the form of a computer program product implemented on one or more computer-usable non-transient storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0215] The present disclosure is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present disclosure. It should be understood that the functions specified in one or more processes in the flowchart and / or one or more blocks in the block diagram can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate the functions for implementing the functions specified in the flowchart. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0216] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0217] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0218] The above-described embodiments are only preferred embodiments of the present invention and are not intended to limit the scope of implementation of the present invention. All equivalent changes made based on the shape, structure and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for controlling an electronic expansion valve of a heat pump system, characterized in that: The heat pump system includes a first heat exchanger arranged outdoors, a second heat exchanger using a water pump unit for water cooling and heat exchange, a compressor, a third heat exchanger for replenishing air to the compressor, a first electronic expansion valve arranged between the first heat exchanger and the third heat exchanger, and a second electronic expansion valve arranged between the third heat exchanger and the second heat exchanger. The compressor is connected between the first heat exchanger and the second heat exchanger through a refrigerant pipeline and a four-way valve. The electronic expansion valve control method includes the following steps: Step S1, the heat pump unit is started and operated, and the controller collects parameters after the compressor starts and operates for a period of time; The parameters collected by the controller include: The maximum fluctuation step number B of the first electronic expansion valve is collected during this period 大N ; This cycle collects the minimum fluctuation step number B of the first electronic expansion valve 小N ; The maximum fluctuation step number B of the first electronic expansion valve is collected during this period 大N Time t 大N ; This cycle collects the minimum fluctuation step number B of the first electronic expansion valve 小N Time t 小N ; The maximum fluctuation step number B of the first electronic expansion valve is collected during this period 大N Superheat parameter P at the moment 大N ; This cycle collects the minimum fluctuation step number B of the first electronic expansion valve 小N Superheat parameter P at the moment 小N ; The maximum fluctuation step number B of the first electronic expansion valve collected in the last fluctuation cycle 大N-1 ; The minimum fluctuation step number B of the first electronic expansion valve collected in the last fluctuation cycle 小N-1 ; The maximum fluctuation step number B of the first electronic expansion valve collected in the last fluctuation cycle 大N-1 Time t 大N-1 ; The minimum fluctuation step number B of the first electronic expansion valve collected in the last fluctuation cycle 小N-1 Time t 小N-1 ; The maximum fluctuation step number B of the first electronic expansion valve collected in the last fluctuation cycle 大N-1 Superheat parameter P at the moment 大N-1 ; The minimum fluctuation step number B of the first electronic expansion valve collected in the last fluctuation cycle 小N-1 Superheat parameter P at the moment 小N-1 ; Among them, this cycle refers to the process of the first electronic expansion valve from the maximum opening to the minimum opening, or the process of the first electronic expansion valve from the minimum opening to the maximum opening, which is collected by the controller. This cycle is identified by the controller automatically calculating the number of actions of the first electronic expansion valve; and according to the hysteresis of the controller controlling the heat pump system, the control process generally satisfies the following rules: the maximum opening of the first electronic expansion valve in the next cycle ≤ the maximum opening of the first electronic expansion valve in this cycle, and the minimum opening of the first electronic expansion valve in the next cycle ≥ the minimum opening of the first electronic expansion valve in this cycle; Step S2, the first electronic expansion valve automatically operates and adjusts according to pid The compressor and the first electronic expansion valve are automatically adjusted according to the corresponding PID control conditions. When the compressor runs stably, the first electronic expansion valve performs stability adjustment according to the following judgment; Step S3, performing a first-level determination condition; When the first electronic expansion valve fluctuates, the number of positive and negative actions B (N) The absolute value of |B (N) |≤b1, it means that the first electronic expansion valve is oscillating around the target value; Otherwise, the process returns to step S2 in which the first electronic expansion valve automatically operates and adjusts according to the pid control condition; Step S4, synchronously perform the secondary determination conditions; When the first electronic expansion valve oscillates around the target value, the following actions are performed in sequence: When the first electronic expansion valve does not oscillate around the target value, the process directly returns to step S2; Step S4.1.1, when the number of positive and negative actions of the first electronic expansion valve fluctuation step number C (N) The absolute value of |C (N) |≤|a【(t 大N-1 -t 大N )+(t 小N-1 -t 小N )】+b2|, it indicates that the first electronic expansion valve has a small range fluctuation trend; after the above conditions are met, the first electronic expansion valve begins to adjust the stability; Step S4.1.2: At this time, the adjustment speed of the first electronic expansion valve will be slowed down to the preset initial adjustment period V a , and the first electronic expansion valve can adjust at most W1 steps each time; Step S4.1.3, run V a After a certain time, check whether the superheat deviation is within the fitted target superheat value range of the ambient temperature and water temperature; When |P 实际过热度 -P 目过热度 |<Superheat deviation upper limit value, superheat deviation upper limit value is based on D*T h 2 +E*T s 2 +F*T h +G*T s +H formula, the regulation rate of the first electronic expansion valve is affected by the superheat change rate to perform regulation cycle correction; this is superheat target identification, the heat pump system can improve reliability when operating within a suitable superheat range, the superheat fitting value is calculated by the formula of the superheat deviation upper limit value, and the ambient temperature value and water temperature value are associated here; When |P 实际过热度 -P 目标过热度 |If it is not within the above-mentioned limited range, return to step S4.1.2 for re-determination; Step S4.1.4: The first electronic expansion valve adjusts the cycle V j =V j-1 *K is adjusted and corrected, and then the first electronic expansion valve is adjusted according to V j The first electronic expansion valve is adjusted at a maximum of W2 steps each time; wherein, when V is calculated for the first time in this step, j-1 =V a , P j Indicates V j-1 The real-time superheat parameter collected by the controller after time, P j-1 Indicates V j-1 The real-time superheat parameter collected by the controller at time; moreover, the following conditions must be met in this step: ①When (P j -P j-1 ) / V j-1 > V1, k = 1 + 【(P 大N-1 -P 小N-1 ) / (t 大N-1 -t 小N-1 )】 / 【(P 大N -P 小N ) / (t 大N -t 小N )】; ②When V2<(P j -P j-1 ) / V j-1 ≤V1, k=k1; ③When V3<(P j -P j-1 ) / V j-1 When ≤V2, k=k2; ④When V4<(P j -P j-1 ) / V j-1 ≤V3, k=k3; ⑤When (P j -P j-1 ) / V j-1 ≤V4, k=k4; Step S4.2.1, |a【(t 大N-1 -t 大N )+(t 小N-1 -t 小N )】+b2|≤When the first electronic expansion valve fluctuates in the positive and negative actions C (N) Absolute value of times|C (N) |≤|a【(t 大N-1 -t 大N )+(t 小N-1 -t 小N )】+b3|, it indicates that the first electronic expansion valve has a large step number fluctuation trend; after the above conditions are met, the electronic expansion valve begins to adjust the stability; Step S4.2.2: At this time, the adjustment speed of the first electronic expansion valve will be slowed down to the preset initial adjustment period V b , and the expansion valve can be adjusted by a maximum of W1 steps each time; Step S4.2.3, run V b After a certain period of time, detect the deviation range of superheat; When |P 实际过热度 -P 目标过热度 |<D*T h 2 +E*T s 2 +F*T h +G*T s +H, the regulation rate of the first electronic expansion valve is affected by the superheat change rate and the regulation cycle is corrected; When |P 实际过热度 -P 目过热度 |If it is not within the above-mentioned limited range, return to step S4.2.2 for re-determination; Step S4.2.4: The first electronic expansion valve adjusts the cycle V j =V j-1 *k is adjusted and corrected, and then the first electronic expansion valve is adjusted according to V j The first electronic expansion valve is regulated in an adjustment cycle, and the first electronic expansion valve is adjusted by a maximum of W2 steps each time; wherein, when V is calculated for the first time in this step j-1 =V b , P j Indicates V j-1 The real-time superheat parameter collected by the controller after time, P j-1 Indicates V j-1 The real-time superheat parameter collected by the controller at time; moreover, the following conditions must be met in this step: ⑥When (P j - P j-1 ) / V j-1 > V1, k = 1 + 【(P 大N-1 - P 小N-1 ) / (t 大N-1 - t 小N-1 )】 / 【(P 大N - P 小N ) / (t 大N - t 小N )】; ⑦When V2<(P j -P j-1 ) / V j-1 When ≤V1, k=k5; ⑧When V3<(P j -P j-1 ) / V j-1 ≤V2, k=k6; ⑨When V4<(P j -P j-1 ) / V j-1 When ≤V3, k=k7; ⑩When (P j -P j-1 ) / V j-1 When ≤V4, k=k8; Step S4.3, when the first electronic expansion valve fluctuates in the positive and negative actions C (N) Absolute value of times|C (N) |>|a【(t 大N-1 -t 大N )+(t 小N-1 -t 小N )】+b3|, the heat pump system maintains the original control mode and automatically operates, automatically returns to the step S2, and the first electronic expansion valve maintains the original pid automatic adjustment mode control; The parameters in the description of all the above steps are as follows: B (N) Indicates the number of times the first electronic expansion valve is operated collected by the controller; C (N) Indicates the number of times the first electronic expansion valve is operated collected by the controller; a is the positive coefficient; b1 is the volatility coefficient; b2 is the volatility coefficient; b3 is the volatility coefficient; P 实际过热度 Indicates the actual superheat value collected by the controller; T h Indicates the real-time ambient temperature value collected by the controller; T s Indicates the real-time water temperature value collected by the controller; D is the superheat coefficient; E is the superheat coefficient; F is the superheat coefficient; G is the superheat coefficient; H is the superheat coefficient; V j To calculate the target valve regulation cycle; V j-1 To calculate the target valve regulation cycle of the last sampling; V a Initial conditioning cycle; V b Initial conditioning cycle; V1 is the valve regulation cycle time boundary value; V2 is the valve regulation cycle time boundary value; V3 is the valve regulation cycle time boundary value; V4 is the valve regulation cycle time boundary value; W1 is the number of valve adjustment steps; W2 is the number of valve adjustment steps; K is the superheat coefficient; K1 is the valve regulating cycle coefficient; K2 is the valve regulating cycle coefficient; K3 is the valve regulating cycle coefficient; K4 is the valve regulating cycle coefficient; K5 is the valve regulating cycle coefficient; K6 is the valve regulating cycle coefficient; K7 is the valve regulating cycle coefficient; K8 is the valve regulating cycle coefficient.

2. The electronic expansion valve control method of a heat pump system according to claim 1, characterized in that: Also includes: a is the positive coefficient, and the optimal value is 0.5; b1 is the volatility coefficient, and the optimal value is 15; b2 is the volatility coefficient, and the optimal value is 5; b3 is the volatility coefficient, and the optimal value is 7; D is the superheat coefficient, and the optimal value is 0.006; E is the superheat coefficient, and the optimal value is 0.002; F is the superheat coefficient, the optimal value is 0.015; G is the superheat coefficient, and the optimal value is 0.001; H is the superheat coefficient, and the optimal value is 1.2; V a Initial adjustment period, and the optimal value is 120s; V b Initial adjustment period, and the optimal value is 180s; V1 is the boundary value of the valve regulating cycle time, and the optimal value is 0.5℃ / min; V2 is the boundary value of the valve regulating cycle time, and the optimal value is 0.4℃ / min; V3 is the boundary value of the valve regulating cycle time, and the optimal value is 0.3℃ / min; V4 is the boundary value of the valve regulation cycle time, and the optimal value is 0.2℃ / min; W1 is the number of valve adjustment steps, and the optimal value is 2; W2 is the number of valve adjustment steps, and the optimal value is 1; K1 is the valve regulating cycle coefficient, and the optimal value is 1.3; K2 is the valve regulating cycle coefficient, and the optimal value is 1.2; K3 is the valve regulating cycle coefficient, and the optimal value is 1.1; K4 is the valve regulating cycle coefficient, and the optimal value is 1; K5 is the valve regulating cycle coefficient, and the optimal value is 1.5; K6 is the valve regulating cycle coefficient, and the optimal value is 1.4; K7 is the valve regulating cycle coefficient, and the optimal value is 1.2; K8 is the valve regulation cycle coefficient, and the optimal value is 1.

3. A control device for a heat pump system, characterized in that: include: Memory; and A processor coupled to the memory is configured to execute the electronic expansion valve control method for a heat pump system according to any one of claims 1 to 2 based on instructions stored in the memory.

4. A low temperature air source heat pump, characterized in that: include: Heat pump system; and A control device for a heat pump system according to claim 3.

5. A computer-readable storage medium, characterized in that: The method comprises computer program instructions, wherein when the computer program instructions are executed by a processor, the electronic expansion valve control method of a heat pump system according to any one of claims 1 to 2 is implemented.

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