A method and device for controlling a full-flow throttling valve in a carbon dioxide heat pump air conditioner

Abstract

This invention discloses a control method and device for a full-throttle valve in a carbon dioxide heat pump system, relating to the field of heat pump system control technology. The control method includes: acquiring the operating mode of the carbon dioxide heat pump system, and based on the acquired operating mode: when the carbon dioxide heat pump system is in heating mode, obtaining the water temperature-related opening degree and pressure-related opening degree based on the water temperature and optimal system pressure, and weighting them to obtain the opening degree of the ERV valve in heating mode; when the carbon dioxide heat pump system is in cooling mode, obtaining the evaporation temperature-related opening degree and pressure-related opening degree based on the evaporation temperature and optimal system pressure, and weighting them to obtain the opening degree of the ERV valve in cooling mode. This invention selects different control strategies by determining the system operating mode and weights the corresponding valve opening results, enabling the heat pump system to operate stably for a long period.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of heat pump system control, in particular to a carbon dioxide heat pump air conditioner full-pass throttling valve control method and device. BACKGROUND

[0002] The carbon dioxide heat pump system can work normally under-30 DEG C and below extreme working conditions, and has good heating effect, without additional high-pressure water PTC (positive temperature coefficient) heating system. The existing research data shows that the carbon dioxide heat pump system principle mostly uses a regenerator plus gas-liquid separator system. The heat pump system needs to heat or cool the battery and passenger compartment at the same time, but in the control process of the two, there are problems of unreasonable energy distribution or control algorithm unable to achieve good distribution, resulting in the phenomenon of passenger compartment being too cold or too hot.

[0003] At present, in the research of carbon dioxide automobile heat pump air conditioner, the existing carbon dioxide heat pump system is mostly designed to have multiple electronic expansion valves, solenoid valves and other system state adjustment devices, and the full-pass throttling valves of the passenger compartment loop and the battery loop are controlled to distribute the refrigeration / heat capacity. The full-pass throttling valve mostly uses single PID (proportion, integral, differential) control or fixed step adjustment of the lifting rate. This control method has poor stability due to the simple algorithm, the hysteresis of the carbon dioxide system is poor, and the delay coefficients are different in the process of temperature rise and fall. Using single PID control or fixed step control will cause the problem of fast temperature rise and slow temperature fall or slow temperature rise and fast temperature fall. Using single monitoring variable cannot timely and accurately feedback the state of the system, and is prone to overshoot and over-temperature. SUMMARY

[0004] In view of the defects in the prior art, the purpose of the present application is to provide a carbon dioxide heat pump air conditioner full-pass throttling valve control method and device, which selects different control strategies by judging the working mode of the system, has separate control processes for heating mode and cooling mode, considers different influencing factors under different working modes, and makes weighted processing on the corresponding valve opening degree result, so as to more reasonably control the full-pass throttling valve of the heat pump system, so that the heat pump system can be stably operated for a long time, and the temperature rise and fall process is relatively fast, stable and accurate.

[0005] To achieve the above purpose, the technical scheme adopted by the present application is:

[0006] The working mode of the carbon dioxide heat pump system is obtained, and according to the obtained working mode:

[0007] When the carbon dioxide heat pump system is in a heating mode, water temperature correlation opening degree and pressure correlation opening degree are obtained based on water temperature of the carbon dioxide heat pump system and optimal pressure of the system, and opening degree of the ERV valve in the heating mode is obtained by weighting;

[0008] When the carbon dioxide heat pump system is in a cooling mode, evaporation temperature correlation opening degree and pressure correlation opening degree are obtained based on evaporation temperature of the carbon dioxide heat pump system and optimal pressure of the system, and opening degree of the ERV valve in the cooling mode is obtained by weighting.

[0009] On the basis of the above technical solution, when the carbon dioxide heat pump system is in a heating mode, water temperature correlation opening degree and pressure correlation opening degree are obtained based on water temperature of the carbon dioxide heat pump system and optimal pressure of the system, and opening degree of the ERV valve in the heating mode is obtained by weighting, and the specific steps include:

[0010] When the carbon dioxide heat pump system is in a heating mode, water temperature correlation opening degree F1 in the heating mode is calculated based on target water temperature of the carbon dioxide heat pump system, current water temperature of the carbon dioxide heat pump system and a PID parameter setting table of the heating process.

[0011] Pressure correlation opening degree F2 in the heating mode is calculated based on target pressure of the carbon dioxide heat pump system, current pressure of the carbon dioxide heat pump system and the PID parameter setting table of the heating process.

[0012] ERV valve opening degree F in the heating mode is calculated based on the calculated water temperature correlation opening degree F1 in the heating mode and corresponding water temperature coefficient X1, and the pressure correlation opening degree F2 in the heating mode and corresponding optimal pressure coefficient X2, and the calculation method is:

[0013] F = X1*F1 + X2*F2

[0014] The carbon dioxide heat pump system is controlled based on the calculated ERV valve opening degree F in the heating mode.

[0015] On the basis of the above technical solution, water temperature correlation opening degree F1 in the heating mode is calculated based on target water temperature of the carbon dioxide heat pump system, current water temperature of the carbon dioxide heat pump system and a PID parameter setting table of the heating process, and the specific steps include:

[0016] Water temperature deviation value is obtained based on a difference between target water temperature of the carbon dioxide heat pump system in the heating mode and current water temperature of the carbon dioxide heat pump system.

[0017] Opening degree increment of the water temperature correlation opening degree in the heating mode is calculated based on the obtained water temperature deviation value and values of Kp, Ki and Kd corresponding to the PID parameter setting table of the heating process, and the calculation formula is:

[0018] ΔF1 = Kp(ΔW_(K) - ΔW_(K-1)) + Ki * ΔW_(K) + Kd(ΔW_(K) - 2ΔW_(K-1) + ΔW_(K-2))

[0019] ΔF1 = Kp(ΔW_(K) - ΔW_(K-1)) + Ki * ΔW_(K) + Kd(ΔW_(K) - 2ΔW_(K-1) + ΔW_(K-2))

[0020] wherein, ΔF1 is the opening increment of the water temperature related opening degree in the heating mode, Kp is a proportional adjustment coefficient, Ki is an integral adjustment coefficient, Kd is a differential adjustment coefficient, ΔW_(K) is the water temperature deviation value at K time, ΔW_(K-1) is the water temperature deviation value at K-1 time, ΔW_(K-2) is the water temperature deviation value at K-2 time;

[0021] Based on the calculated opening increment of the water temperature related opening degree in the heating mode and the current opening degree of the water temperature related opening degree in the heating mode, the water temperature related opening degree F1 in the heating mode is calculated, and the calculation formula is:

[0022] F1 = F1_Current + ΔF1

[0023] wherein, F1_Current is the current opening degree of the water temperature related opening degree in the heating mode.

[0024] Based on the above technical scheme, the target pressure of the carbon dioxide heat pump system, the current pressure of the carbon dioxide heat pump system and the PID parameter setting table of the heating process are used to calculate the pressure related opening degree F2 in the heating mode, and the specific steps include:

[0025] Based on the difference between the target pressure of the carbon dioxide heat pump system in the heating mode and the current pressure of the carbon dioxide heat pump system, the pressure deviation value in the heating mode is obtained;

[0026] Based on the obtained pressure deviation value in the heating mode and the values of Kp, Ki and Kd in the PID parameter setting table of the heating process, the opening increment of the pressure related opening degree in the heating mode is calculated, and the calculation formula is:

[0027] ΔF2 = Kp(ΔS_(K) - ΔS_(K-1)) + Ki * ΔS_(K) + Kd(ΔS_(K) - 2ΔS_(K-1) + ΔS_(K-2))

[0028] Kd(ΔS_(K) - 2ΔS_(K-1) + ΔS_(K-2))

[0029] wherein, ΔF2 is the opening increment of the pressure related opening degree in the heating mode, ΔS_(K) is the pressure deviation value in the heating mode at K time, ΔS_(K-1) is the pressure deviation value in the heating mode at K-1 time, ΔS_(K-2) is the pressure deviation value in the heating mode at K-2 time;

[0030] The heating mode pressure-related opening degree F2 is calculated based on the calculated opening degree increment of the heating mode pressure-related opening degree and the current opening degree of the heating mode pressure-related opening degree, and the calculation formula is:

[0031] F2=F2_Current+ΔF2

[0032] F2_Current is the current opening degree of the heating mode pressure-related opening degree.

[0033] On the basis of the above technical scheme, the value of the water temperature coefficient X1 is less than the value of the optimal pressure coefficient X2.

[0034] On the basis of the above technical scheme, when the working mode of the carbon dioxide heat pump system is the cooling mode, the evaporation temperature-related opening degree and the pressure-related opening degree are obtained based on the evaporation temperature of the carbon dioxide heat pump system and the optimal pressure of the system, and the opening degree of the ERV valve in the cooling mode is obtained by weighting, and the specific steps include:

[0035] When the working mode of the carbon dioxide heat pump system is the cooling mode, the evaporation temperature-related opening degree P1 in the cooling mode is calculated based on the target evaporation temperature of the carbon dioxide heat pump system, the current evaporation temperature of the carbon dioxide heat pump system, and the PID parameter setting table of the cooling process,

[0036] The pressure-related opening degree P2 in the cooling mode is calculated based on the target system pressure of the carbon dioxide heat pump system, the current system pressure of the carbon dioxide heat pump system, and the PID parameter setting table of the cooling process.

[0037] The opening degree P of the ERV valve in the cooling mode is calculated based on the calculated evaporation temperature-related opening degree P1 in the cooling mode and the corresponding evaporation temperature coefficient X3, and the pressure-related opening degree P2 in the cooling mode and the corresponding optimal pressure coefficient X4, and the calculation method is:

[0038] P=X3*P1+X4*P2

[0039] The carbon dioxide heat pump system is controlled based on the calculated opening degree P of the ERV valve in the cooling mode.

[0040] On the basis of the above technical scheme, the evaporation temperature-related opening degree P1 in the cooling mode is calculated based on the target evaporation temperature of the carbon dioxide heat pump system, the current evaporation temperature of the carbon dioxide heat pump system, and the PID parameter setting table of the cooling process, and the specific steps include:

[0041] The evaporation temperature deviation value is obtained based on the difference between the target evaporation temperature of the carbon dioxide heat pump system in the cooling mode and the current evaporation temperature of the carbon dioxide heat pump system.

[0042] Based on the obtained evaporation temperature deviation value and the corresponding Kp, Ki and Kd values in the refrigeration process PID parameter setting table, an opening increment of the evaporation temperature associated opening degree in the refrigeration mode is calculated, and the calculation formula is:

[0043] ΔP1=Kp(ΔT_(K)-ΔT_(K-1))+Ki*ΔW_(K)+

[0044] Kd(ΔT_(K)-2ΔT_(K-1)+ΔT_(K-2))

[0045] Wherein, ΔP1 is the opening increment of the evaporation temperature associated opening degree in the refrigeration mode, ΔT_(K) is the evaporation temperature deviation value at K time, ΔT_(K-1) is the evaporation temperature deviation value at K-1 time, and ΔT_(K-2) is the evaporation temperature deviation value at K-2 time.

[0046] Based on the calculated opening increment of the evaporation temperature associated opening degree in the refrigeration mode and the current opening degree of the evaporation temperature associated opening degree in the refrigeration mode, the evaporation temperature associated opening degree P1 in the refrigeration mode is calculated, and the calculation formula is:

[0047] P1=P1_Current+ΔP1

[0048] Wherein, P1_Current is the current opening degree of the evaporation temperature associated opening degree in the refrigeration mode.

[0049] On the basis of the above technical scheme, the target system pressure of the carbon dioxide heat pump system, the current system pressure of the carbon dioxide heat pump system and the refrigeration process PID parameter setting table are used to calculate the pressure associated opening degree P2 in the refrigeration mode, and the specific calculation steps are as follows:

[0050] Based on the difference between the target system pressure of the carbon dioxide heat pump system in the refrigeration mode and the current system pressure of the carbon dioxide heat pump system, the pressure deviation value in the refrigeration mode is obtained.

[0051] Based on the obtained pressure deviation value in the refrigeration mode and the corresponding Kp, Ki and Kd values in the refrigeration process PID parameter setting table, the opening increment of the pressure associated opening degree in the refrigeration mode is calculated, and the calculation formula is:

[0052] ΔP2=Kp(ΔS_(K)-ΔS_(K-1))+Ki*ΔS_(K)+

[0053] Kd(ΔS_(K)-2ΔS_(K-1)+ΔS_(K-2))

[0054] Wherein, ΔP2 is the opening increment of the pressure correlation opening in the refrigeration mode, ΔS_(K) is the pressure deviation value in the refrigeration mode at K moment, ΔS_(K-1) is the pressure deviation value in the refrigeration mode at K-1 moment, and ΔS_(K-2) is the pressure deviation value in the refrigeration mode at K-2 moment.

[0055] Based on the calculated opening increment of the pressure correlation opening in the refrigeration mode and the current opening of the pressure correlation opening in the refrigeration mode, the pressure correlation opening P2 in the refrigeration mode is calculated, and the calculation formula is:

[0056] P2 = P2_Current + ΔP2

[0057] Wherein, P2_Current is the current opening of the pressure correlation opening in the refrigeration mode.

[0058] On the basis of the above technical scheme, the value of the evaporation temperature coefficient X3 is less than the value of the optimal pressure coefficient X4.

[0059] The application also provides a control device of a carbon dioxide heat pump system air conditioner full-through throttling valve, comprising:

[0060] An acquisition module is configured to acquire a working mode of the carbon dioxide heat pump system.

[0061] An execution module is configured to, according to the working mode acquired by the acquisition module, when the working mode of the carbon dioxide heat pump system is a heating mode, obtain a water temperature correlation opening and a pressure correlation opening based on the water temperature of the carbon dioxide heat pump system and the optimal pressure of the system, and obtain the opening of the ERV valve in the heating mode by weighting; when the working mode of the carbon dioxide heat pump system is a refrigeration mode, obtain an evaporation temperature correlation opening and a pressure correlation opening based on the evaporation temperature of the carbon dioxide heat pump system and the optimal pressure of the system, and obtain the opening of the ERV valve in the refrigeration mode by weighting.

[0062] Compared with the prior art, the application has the advantages that: the application selects different control strategies by judging the working mode of the system, has separate control processes for the heating mode and the refrigeration mode, considers different influencing factors in different working modes, and performs weighting processing on the corresponding valve opening results, so that the full-through throttling valve of the heat pump system can be more reasonably controlled, the heat pump system can be stably operated for a long time, and the system state can be ensured to be normal without protection state. BRIEF DESCRIPTION OF DRAWINGS

[0063] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments description. Obviously, the drawings in the following description only some of the embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0064] Figure 1 The flowchart of the carbon dioxide heat pump air conditioner full-pass throttling valve control method in the embodiment of the present application is shown in the figure.

[0065] Figure 2 The system principle diagram of the carbon dioxide heat pump air conditioner full-pass throttling valve control method in the embodiment of the present application is shown in the figure.

[0066] Figure 3 The complete flowchart of the carbon dioxide heat pump air conditioner full-pass throttling valve control method in the embodiment of the present application is shown in the figure. DETAILED DESCRIPTION

[0067] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the following will combine the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all the embodiments.

[0068] Referring to Figure 1 The embodiment of the present application provides a carbon dioxide heat pump air conditioner full-pass throttling valve control method, which comprises the following steps:

[0069] Obtaining the working mode of the carbon dioxide heat pump system, and according to the obtained working mode:

[0070] When the working mode of the carbon dioxide heat pump system is the heating mode, the water temperature correlation opening degree and the pressure correlation opening degree are obtained based on the water temperature and the system optimal pressure of the carbon dioxide heat pump system, and the opening degree of the ERV valve in the heating mode is obtained by weighting.

[0071] When the working mode of the carbon dioxide heat pump system is the cooling mode, the evaporation temperature correlation opening degree and the pressure correlation opening degree are obtained based on the evaporation temperature and the system optimal pressure of the carbon dioxide heat pump system, and the opening degree of the ERV valve in the cooling mode is obtained by weighting.

[0072] This invention primarily selects different control strategies by determining the operating mode of the carbon dioxide heat pump system. Heating and cooling modes have different control procedures. First, the operating mode of the carbon dioxide heat pump system is obtained. Based on the obtained operating mode, if the operating mode is determined to be heating mode, the water temperature-related opening and pressure-related opening are obtained based on the water temperature and optimal system pressure. These openings are then weighted to obtain the opening of the ERV valve in heating mode. If the operating mode is determined to be cooling mode, the evaporation temperature-related opening and pressure-related opening are obtained based on the evaporation temperature and optimal system pressure. These openings are then weighted to obtain the opening of the ERV valve in cooling mode. The ERV valve is a full-throttle valve, and its specific configuration is as follows: Figure 2 The location shown in the figure Figure 2 This is a system schematic diagram of a carbon dioxide heat pump air conditioner full-pass throttling valve control method according to an embodiment of the present invention. Figure 2 OHX is the heat exchanger, FWV is the flow vane valve, HAVC is the air conditioning system, M is the motor, and ICC+IHC is the gas-liquid separator + intermediate heat exchanger.

[0073] In this invention, when the carbon dioxide heat pump system is in heating mode, the opening degree related to water temperature and the opening degree related to pressure are obtained based on the water temperature and optimal system pressure of the carbon dioxide heat pump system, and the opening degree of the ERV valve in heating mode is obtained by weighting. The specific steps include:

[0074] When the carbon dioxide heat pump system is in heating mode, the water temperature associated opening F1 in heating mode is calculated based on the target water temperature of the carbon dioxide heat pump system, the current water temperature of the carbon dioxide heat pump system, and the PID parameter setting table of the heating process.

[0075] Based on the target pressure of the carbon dioxide heat pump system, the current pressure of the carbon dioxide heat pump system, and the PID parameter setting table for the heating process, calculate the pressure-related opening degree F2 in the heating mode.

[0076] Based on the calculated water temperature-related opening F1 and corresponding water temperature coefficient X1 in the heating mode, and the pressure-related opening F2 and corresponding optimal pressure coefficient X2 in the heating mode, the ERV valve opening F in the heating mode is calculated. The calculation method is as follows:

[0077] F = X1 * F1 + X2 * F2

[0078] The carbon dioxide heat pump system is controlled based on the calculated opening degree F of the ERV valve under the heating mode.

[0079] When the working mode of the carbon dioxide is determined to be the heating mode, the water temperature correlation opening degree and the pressure correlation opening degree are obtained based on the water temperature of the carbon dioxide heat pump system and the optimal pressure of the system, and the obtained water temperature correlation opening degree and the pressure correlation opening degree are weighted to obtain the opening degree of the ERV valve in the heating mode. When the working mode of the carbon dioxide heat pump system is the heating mode, the water temperature correlation opening degree F1 in the heating mode is calculated based on the target water temperature of the carbon dioxide heat pump system, the current water temperature of the carbon dioxide heat pump system and the PID parameter setting table in the heating process. Then, the pressure correlation opening degree F2 in the heating mode is calculated based on the target pressure of the carbon dioxide heat pump system, the current pressure of the carbon dioxide heat pump system and the PID parameter setting table in the heating process. The ERV valve opening degree F in the heating mode is calculated based on the calculated water temperature correlation opening degree F1 in the heating mode and the corresponding water temperature coefficient X1, and the pressure correlation opening degree F2 in the heating mode and the corresponding optimal pressure coefficient X2, and the calculation formula is F = X1*F1 + X2*F2. The carbon dioxide heat pump system is controlled based on the calculated ERV valve opening degree F in the heating mode, so as to realize the temperature control of the vehicle passenger compartment.

[0080] In the present application, the water temperature correlation opening degree F1 in the heating mode is calculated based on the target water temperature of the carbon dioxide heat pump system, the current water temperature of the carbon dioxide heat pump system and the PID parameter setting table in the heating process, and the specific steps include:

[0081] The water temperature deviation value is obtained based on the difference between the target water temperature of the carbon dioxide heat pump system in the heating mode and the current water temperature of the carbon dioxide heat pump system.

[0082] The opening increment of the water temperature correlation opening degree in the heating mode is calculated based on the obtained water temperature deviation value and the values of Kp, Ki and Kd in the PID parameter setting table in the heating process, and the calculation formula is:

[0083] ΔF1 = Kp(ΔW_(K) - ΔW_(K-1)) + Ki*ΔW_(K) + Kd(ΔW_(K) - 2ΔW_(K-1) + ΔW_(K-2))

[0084] Kd(ΔW_(K) - 2ΔW_(K-1) + ΔW_(K-2))

[0085] Wherein, ΔF1 is the opening increment of the water temperature correlation opening degree in the heating mode, Kp is the proportional adjustment coefficient, Ki is the integral adjustment coefficient, Kd is the differential adjustment coefficient, ΔW_(K) is the water temperature deviation value at K time, ΔW_(K-1) is the water temperature deviation value at K-1 time, and ΔW_(K-2) is the water temperature deviation value at K-2 time.

[0086] The water temperature correlation opening degree F1 in the heating mode is calculated based on the calculated opening increment of the water temperature correlation opening degree in the heating mode and the current opening degree of the water temperature correlation opening degree in the heating mode, and the calculation formula is:

[0087] F1 = F1_Current + ΔF1

[0088] Wherein, F1_Current is the current opening degree of water temperature related opening degree in heating mode.

[0089] That is, based on the target water temperature of the carbon dioxide heat pump system, the current water temperature of the carbon dioxide heat pump system and the heating process PID parameter setting table, the water temperature related opening degree F1 in heating mode is calculated, and the specific steps are as follows: first, the water temperature deviation value in heating mode of the carbon dioxide heat pump system is calculated, which is obtained by subtracting the current water temperature from the target water temperature in heating mode of the carbon dioxide heat pump system; then, based on the obtained water temperature deviation value and the corresponding Kp, Ki and Kd values in the heating process PID parameter setting table, see Table 1, Table 1 is a heating process PID parameter setting table, according to the size of the calculated water temperature deviation value, the corresponding Kp, Ki and Kd values can be obtained, and the corresponding Kp, Ki and Kd values are substituted into the formula to calculate the opening degree increment of the water temperature related opening degree in heating mode, and the calculation formula is:

[0090] ΔF1 = Kp (ΔW_(K) - ΔW_(K-1)) + Ki * ΔW_(K) + Kd (ΔW_(K) - 2ΔW_(K-1) + ΔW_(K-2))

[0091] Kd (ΔW_(K) - 2ΔW_(K-1) + ΔW_(K-2))

[0092] The opening degree increment of the water temperature related opening degree in heating mode calculated and the current opening degree of the water temperature related opening degree in heating mode are added to calculate the water temperature related opening degree F1 in heating mode, and the calculation formula is F1 = F1_Current + ΔF1.

[0093] Table 1 Heating process PID parameter setting table

[0094] Serial number Water temperature / pressure deviation value KP KI KD 1 ≤-10 13 6 8 2 ≤-5 9 4 4 3 ≤-3 7 3 3 4 ≤0 6 2 2 5 ≤5 8 3 5 6 ≤10 10 5 6 7 ≤15 12 6 7 8 ＞15 14 8 9

[0095] In the application, the target pressure of the carbon dioxide heat pump system, the current pressure of the carbon dioxide heat pump system and the heating process PID parameter setting table are used to calculate the pressure related opening degree F2 in heating mode, and the specific steps include:

[0096] Based on the difference between the target pressure of the carbon dioxide heat pump system in heating mode and the current pressure of the carbon dioxide heat pump system, the pressure deviation value in heating mode is obtained;

[0097] Based on the obtained pressure deviation value in heating mode and the corresponding Kp, Ki and Kd values in the heating process PID parameter setting table, the opening degree increment of the pressure related opening degree in heating mode is calculated, and the calculation formula is:

[0098] ΔF2 = Kp(ΔS_(K) - ΔS_(K-1)) + Ki * ΔS_(K) + Kd(ΔS_(K) - 2ΔS_(K-1) + ΔS_(K-2))

[0099] ΔF2 = Kp(ΔS_(K) - ΔS_(K-1)) + Ki * ΔS_(K) + Kd(ΔS_(K) - 2ΔS_(K-1) + ΔS_(K-2))

[0100] Wherein, ΔF2 is the opening increment of the pressure-related opening degree in the heating mode, ΔS_(K) is the pressure deviation value at K time in the heating mode, ΔS_(K-1) is the pressure deviation value at K-1 time in the heating mode, and ΔS_(K-2) is the pressure deviation value at K-2 time in the heating mode.

[0101] Based on the calculated opening increment of the pressure-related opening degree in the heating mode and the current opening degree of the pressure-related opening degree in the heating mode, the pressure-related opening degree F2 in the heating mode is calculated, and the calculation formula is:

[0102] F2 = F2_Current + ΔF2

[0103] Wherein, F2_Current is the current opening degree of the pressure-related opening degree in the heating mode.

[0104] That is, based on the target pressure of the carbon dioxide heat pump system, the current pressure of the carbon dioxide heat pump system and the PID parameter setting table in the heating process, the pressure-related opening degree F2 in the heating mode is calculated. The specific steps are as follows: first, the pressure deviation value in the heating mode is calculated, which is obtained by subtracting the current pressure of the carbon dioxide heat pump system from the target pressure of the carbon dioxide heat pump system in the heating mode. Then, according to the calculated pressure deviation value, the corresponding values of Kp, Ki and Kd can be obtained by referring to Table 1. Then, the values of Kp, Ki and Kd are substituted into the formula to calculate the opening increment of the pressure-related opening degree in the heating mode, and the calculation formula is:

[0105] ΔF2 = Kp(ΔS_(K) - ΔS_(K-1)) + Ki * ΔS_(K) + Kd(ΔS_(K) - 2ΔS_(K-1) + ΔS_(K-2))

[0106] ΔF2 = Kp(ΔS_(K) - ΔS_(K-1)) + Ki * ΔS_(K) + Kd(ΔS_(K) - 2ΔS_(K-1) + ΔS_(K-2))

[0107] The calculated opening increment of the pressure-related opening degree in the heating mode is added to the current opening degree of the pressure-related opening degree, that is, the pressure-related opening degree F2 in the heating mode is obtained, and the calculation formula is F2 = F2_Current + ΔF2.

[0108] In the PID calculation process, instead of using a single PID adjustment parameter, a list method is used to correct Kp, Ki and Kd parameters according to different deviation values.

[0109] When the carbon dioxide heat pump system is in the heating mode, in the temperature rising stage, the values of Kp, Ki and Kd are set to be large to increase the rapid temperature rising demand; in the stable stage, the values of Kp, Ki and Kd are set to be small to reduce the fluctuation of the system. In the overshoot stage, the values of Kp, Ki and Kd can be set to be large to increase the rapid return ability of the system and the stability of the system.

[0110] In the application, the value of the water temperature coefficient X1 is less than the value of the optimal pressure coefficient X2.

[0111] When the valve opening degree is weighted, the control target and stability of the system are considered in addition to the optimal pressure. In the embodiment, the value of the water temperature coefficient X1 is set to be about 0.1, the value of the optimal pressure coefficient X2 is set to be about 0.9, and the values of X1 and X2 can be adjusted in a certain range.

[0112] In the application, when the working mode of the carbon dioxide heat pump system is the cooling mode, the evaporation temperature correlation opening degree and the pressure correlation opening degree are obtained based on the evaporation temperature of the carbon dioxide heat pump system and the optimal pressure of the system, and the opening degree of the ERV valve in the cooling mode is obtained by weighting, and the specific steps include:

[0113] When the working mode of the carbon dioxide heat pump system is the cooling mode, the evaporation temperature correlation opening degree P1 in the cooling mode is calculated based on the target evaporation temperature of the carbon dioxide heat pump system, the current evaporation temperature of the carbon dioxide heat pump system and the PID parameter setting table of the cooling process.

[0114] The pressure correlation opening degree P2 in the cooling mode is calculated based on the target system pressure of the carbon dioxide heat pump system, the current system pressure of the carbon dioxide heat pump system and the PID parameter setting table of the cooling process.

[0115] The opening degree P of the ERV valve in the cooling mode is calculated based on the calculated evaporation temperature correlation opening degree P1 and the corresponding evaporation temperature coefficient X3 in the cooling mode, and the pressure correlation opening degree P2 and the corresponding optimal pressure coefficient X4 in the cooling mode, and the calculation method is:

[0116] P = X3 * P1 + X4 * P2

[0117] The carbon dioxide heat pump system is controlled based on the calculated opening degree P of the ERV valve in the cooling mode.

[0118] When the working mode of the carbon dioxide heat pump system is the cooling mode, the evaporation temperature correlation opening degree and the pressure correlation opening degree are obtained based on the evaporation temperature of the carbon dioxide heat pump system and the optimal pressure of the system, and the evaporation temperature correlation opening degree and the pressure correlation opening degree are weighted to obtain the opening degree of the ERV valve in the cooling mode. The specific steps are as follows: first, based on the target evaporation temperature of the carbon dioxide heat pump system, the current evaporation temperature of the carbon dioxide heat pump system and the PID parameter setting table of the cooling process, the evaporation temperature correlation opening degree P1 in the cooling mode is calculated; then, based on the calculated evaporation temperature correlation opening degree P1 in the cooling mode and the corresponding evaporation temperature coefficient X3, and the pressure correlation opening degree P2 in the cooling mode and the corresponding optimal pressure coefficient X4, the opening degree P of the ERV valve in the cooling mode is calculated, and the calculation method is P=X3*P1+X4*P2; the carbon dioxide heat pump system is controlled based on the calculated opening degree P of the ERV valve in the cooling mode.

[0119] In the present application, the target evaporation temperature of the carbon dioxide heat pump system, the current evaporation temperature of the carbon dioxide heat pump system and the PID parameter setting table of the cooling process are used to calculate the evaporation temperature correlation opening degree P1 in the cooling mode, and the specific steps include:

[0120] Based on the difference between the target evaporation temperature of the carbon dioxide heat pump system in the cooling mode and the current evaporation temperature of the carbon dioxide heat pump system, the evaporation temperature deviation value is obtained;

[0121] Based on the obtained evaporation temperature deviation value and the values of Kp, Ki and Kd in the PID parameter setting table of the cooling process, the opening increment of the evaporation temperature correlation opening degree in the cooling mode is calculated, and the calculation formula is:

[0122] ΔP1=Kp(ΔT_(K)-ΔT_(K-1))+Ki*ΔW_(K)+

[0123] Kd(ΔT_(K)-2ΔT_(K-1)+ΔT_(K-2))

[0124] Wherein, ΔP1 is the opening increment of the evaporation temperature correlation opening degree in the cooling mode, ΔT_(K) is the evaporation temperature deviation value at time K, ΔT_(K-1) is the evaporation temperature deviation value at time K-1, and ΔT_(K-2) is the evaporation temperature deviation value at time K-2;

[0125] Based on the calculated opening increment of the evaporation temperature correlation opening degree in the cooling mode and the current opening degree of the evaporation temperature correlation opening degree in the cooling mode, the evaporation temperature correlation opening degree P1 in the cooling mode is calculated, and the calculation formula is:

[0126] P1=P1_Current+ΔP1

[0127] Wherein, P1_Current is the current opening degree of the opening degree associated with the evaporation temperature in the refrigeration mode.

[0128] That is, the target evaporation temperature of the carbon dioxide heat pump system, the current evaporation temperature of the carbon dioxide heat pump system and the refrigeration process PID parameter setting table, the specific steps for calculating the opening degree associated with the evaporation temperature P1 in the refrigeration mode are as follows: first, calculate the evaporation temperature deviation value in the refrigeration mode, which is obtained by subtracting the current evaporation temperature of the carbon dioxide heat pump system from the target evaporation temperature of the carbon dioxide heat pump system in the refrigeration mode, then according to the calculated evaporation temperature deviation value, find the corresponding Kp, Ki and Kd values in the refrigeration process PID parameter setting table, see Table 2, which is a refrigeration process PID parameter setting table, according to the evaporation temperature deviation value, determine the corresponding Kp, Ki and Kd values in the table, and substitute the Kp, Ki and Kd values into the formula to calculate the opening degree increment of the opening degree associated with the evaporation temperature in the refrigeration mode, and the calculation formula is:

[0129] ΔP1=Kp(ΔT_(K)-ΔT_(K-1))+Ki*ΔW_(K)+

[0130] Kd(ΔT_(K)-2ΔT_(K-1)+ΔT_(K-2))

[0131] Then add the calculated opening degree increment of the opening degree associated with the evaporation temperature in the refrigeration mode to the current opening degree of the opening degree associated with the evaporation temperature in the refrigeration mode to obtain the opening degree associated with the evaporation temperature P1 in the refrigeration mode, and the calculation formula is P1=P1_Current+ΔP1.

[0132] Table 2 refrigeration process PID parameter setting table

[0133]

[0134]

[0135] In the present application, the target system pressure of the carbon dioxide heat pump system, the current system pressure of the carbon dioxide heat pump system and the refrigeration process PID parameter setting table are used to calculate the pressure associated opening degree P2 in the refrigeration mode, and the specific calculation steps are as follows:

[0136] Based on the difference between the target system pressure of the carbon dioxide heat pump system in the refrigeration mode and the current system pressure of the carbon dioxide heat pump system, the pressure deviation value in the refrigeration mode is obtained.

[0137] Based on the obtained pressure deviation value in the refrigeration mode and the corresponding Kp, Ki, Ki and Kd values in the refrigeration process PID parameter setting table, the opening degree increment of the pressure associated opening degree in the refrigeration mode is calculated, and the calculation formula is:

[0138] ΔP2 = Kp(AS_(K) - AS_(K-1)) + Ki * AS_(K) + Kd(AS_(K) - 2AS_(K-1) + AS_(K-2))

[0139] ΔP2 = Kp(AS_(K) - AS_(K-1)) + Ki * AS_(K) + Kd(AS_(K) - 2AS_(K-1) + AS_(K-2))

[0140] wherein, ΔP2 is the opening increment of the pressure correlation opening degree in the refrigeration mode, AS_(K) is the pressure deviation value at K time, AS_(K-1) is the pressure deviation value at K-1 time, and AS_(K-2) is the pressure deviation value at K-2 time;

[0141] Based on the calculated opening increment of the pressure correlation opening degree in the refrigeration mode and the current opening degree of the pressure correlation opening degree in the refrigeration mode, the pressure correlation opening degree P2 in the refrigeration mode is calculated, and the calculation formula is:

[0142] P2 = P2_Current + ΔP2

[0143] wherein, P2_Current is the current opening degree of the pressure correlation opening degree in the refrigeration mode.

[0144] That is, based on the carbon dioxide heat pump system target system pressure, the carbon dioxide heat pump system current system pressure and the refrigeration process PID parameter setting table, the specific steps of calculating the pressure correlation opening degree P2 in the refrigeration mode are to first calculate the pressure deviation value in the refrigeration mode, which is obtained by subtracting the carbon dioxide heat pump system current system pressure from the carbon dioxide heat pump system target system pressure, and then finding the corresponding Kp, Ki and Kd values in the refrigeration process PID parameter setting table according to the calculated pressure deviation value, and substituting them into the calculation formula to obtain the opening increment of the pressure correlation opening degree in the refrigeration mode, and the calculation formula is:

[0145] ΔP2 = Kp(AS_(K) - AS_(K-1)) + Ki * AS_(K) + Kd(AS_(K) - 2AS_(K-1) + AS_(K-2))

[0146] ΔP2 = Kp(AS_(K) - AS_(K-1)) + Ki * AS_(K) + Kd(AS_(K) - 2AS_(K-1) + AS_(K-2))

[0147] The calculated opening increment of the pressure correlation opening degree in the refrigeration mode is added to the current opening degree of the pressure correlation opening degree in the refrigeration mode to obtain the pressure correlation opening degree P2 in the refrigeration mode, and the calculation formula is P2 = P2_Current + ΔP2.

[0148] When the carbon dioxide heat pump system is in the cooling mode, the values of Kp, Ki and Kd are set to be larger to increase the rapid cooling demand, and the values of Kp, Ki and Kd are set to be smaller to reduce the fluctuation of the system in the stable stage. The values of Kp, Ki and Kd can be set to be larger in the overshoot stage, so that the rapid recovery ability of the system is increased, and the stability of the system is increased.

[0149] In the present application, the value of the evaporation temperature coefficient X3 is less than the value of the optimal pressure coefficient X4.

[0150] That is, when the valve opening degree is weighted, the optimal pressure is considered, and the control target and stability of the system are also considered. In the embodiment of the present application, the value of the evaporation temperature coefficient X3 is set to be about 0.1, the value of the optimal pressure coefficient X4 is set to be about 0.9, and the value of X3 and the value of X4 can be adjusted within a certain range.

[0151] Referring to Figure 3 As shown in the complete flowchart of the embodiment of the present application, first, step A is performed to obtain the working mode of the carbon dioxide heat pump system and to determine the obtained working mode. If the obtained working mode is the heating mode, step B is performed to calculate F1 and F2 according to the calculation formula of the water temperature associated opening degree F1 in the heating mode and the calculation formula of the pressure associated opening degree F2 in the heating mode. Then, step C is performed to calculate the ERV valve opening degree F in the heating mode according to the formula F=X1*F1+X2*F2, X1 is the water temperature coefficient X1 in the heating mode, and X2 is the optimal pressure coefficient in the heating mode. Then, step D is performed to control the carbon dioxide heat pump system according to the calculated ERV valve opening degree F in the heating mode. If the obtained working mode is the cooling mode, step E is performed to calculate the values of the evaporation temperature associated opening degree P1 in the cooling mode and the pressure associated opening degree P2 in the cooling mode according to the calculation formula of the evaporation temperature associated opening degree P1 in the cooling mode and the calculation formula of the pressure associated opening degree P2 in the cooling mode. Then, step F is performed to calculate the opening degree P of the ERV valve in the cooling mode according to the formula P=X3*P1+X4*P2, X3 is the evaporation temperature coefficient in the corresponding cooling mode, and X4 is the optimal pressure coefficient in the corresponding cooling mode. Then, step D is performed to control the carbon dioxide heat pump system according to the calculated opening degree P of the ERV valve in the cooling mode.

[0152] The embodiment of the present application also provides a control device of a carbon dioxide heat pump system air conditioner full-pass throttling valve, which comprises:

[0153] An obtaining module is configured to obtain the working mode of the carbon dioxide heat pump system.

[0154] The execution module is used for obtaining the working mode obtained by the acquisition module, when the working mode of the carbon dioxide heat pump system is the heating mode, obtaining the water temperature correlation opening degree and the pressure correlation opening degree based on the water temperature of the carbon dioxide heat pump system and the optimal pressure of the system, and weighting to obtain the opening degree of the ERV valve in the heating mode; when the working mode of the carbon dioxide heat pump system is the cooling mode, obtaining the evaporation temperature correlation opening degree and the pressure correlation opening degree based on the evaporation temperature of the carbon dioxide heat pump system and the optimal pressure of the system, and weighting to obtain the opening degree of the ERV valve in the cooling mode.

[0155] The execution module is used for obtaining the working mode obtained by the acquisition module, when the working mode of the carbon dioxide heat pump system is the heating mode, obtaining the water temperature correlation opening degree and the pressure correlation opening degree based on the water temperature of the carbon dioxide heat pump system and the optimal pressure of the system, and weighting to obtain the opening degree of the ERV valve in the heating mode; when the working mode of the carbon dioxide heat pump system is the cooling mode, obtaining the evaporation temperature correlation opening degree and the pressure correlation opening degree based on the evaporation temperature of the carbon dioxide heat pump system and the optimal pressure of the system, and weighting to obtain the opening degree of the ERV valve in the cooling mode.

[0156] The above only is the specific implementation of the present application, enables the person skilled in the art to understand or implement the present application. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the application. Accordingly, the present application will not be limited to the embodiments shown herein but will be accorded the widest scope consistent with the principles and novel features shown herein.

[0157] The present application is described with reference to flowcharts and / or block diagrams of the method, device (system) and computer program product according to the embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of the flows and / or blocks in the flowcharts and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device produce a machine that implements the flowcharts and / or block diagrams. Figure 1one or more processes and / or blocks Figure 1 means for performing the function specified by the one or more blocks

Claims

1. A control method of a carbon dioxide heat pump air conditioning full-pass throttling valve, characterized by, The method comprises the following steps: obtaining the working mode of the carbon dioxide heat pump system, and obtaining water temperature correlation opening degree and pressure correlation opening degree based on the water temperature and the optimal system pressure of the carbon dioxide heat pump system according to the obtained working mode, and weighting to obtain the opening degree of the ERV valve in the heating mode; obtaining the opening degree of the ERV valve in the heating mode based on the water temperature correlation opening degree and the pressure correlation opening degree when the working mode of the carbon dioxide heat pump system is the heating mode; obtaining the opening degree of the ERV valve in the cooling mode based on the evaporation temperature correlation opening degree and the pressure correlation opening degree when the working mode of the carbon dioxide heat pump system is the cooling mode; The specific steps of obtaining the opening degree of the ERV valve in the heating mode based on the water temperature correlation opening degree and the pressure correlation opening degree when the working mode of the carbon dioxide heat pump system is the heating mode comprise: When the working mode of the carbon dioxide heat pump system is the heating mode, based on the target water temperature of the carbon dioxide heat pump system, the current water temperature of the carbon dioxide heat pump system and the PID parameter setting table of the heating process, the water temperature related opening degree in the heating mode is calculated ; Based on the carbon dioxide heat pump system target pressure, carbon dioxide heat pump system current pressure and the heating process PID parameter setting table, the pressure correlation opening degree in the heating mode is calculated ; based on the calculated water temperature associated opening degree in heating mode and the corresponding water temperature coefficient and the pressure associated opening degree in heating mode and the corresponding optimal pressure coefficient , the ERV valve opening degree in heating mode is calculated The calculation method is: based on the calculated opening of the erv valve in heating mode controlling a carbon dioxide heat pump system.

2. The control method of claim 1, wherein, The carbon dioxide heat pump system target water temperature, carbon dioxide heat pump system current water temperature and heating process PID parameter setting table are used to calculate the water temperature related opening degree in the heating mode The specific steps include: obtaining a water temperature deviation value based on the difference between the target water temperature of the carbon dioxide heat pump system in the heating mode and the current water temperature of the carbon dioxide heat pump system; Based on the obtained water temperature deviation value and the corresponding PID parameter setting table for the heating process , and The value is used to calculate the increment of the water temperature-related opening in the heating mode. The calculation formula is: wherein, an opening increment of the water temperature associated opening for the heating mode, a proportional regulation coefficient, an integral regulation coefficient, a differential regulation coefficient, is a water temperature deviation value at the time point, is a water temperature deviation value at the time point, is a water temperature deviation value at the time point; Based on the calculated opening increment of the water temperature associated opening degree in the heating mode and the current opening degree of the water temperature associated opening degree in the heating mode, the water temperature associated opening degree in the heating mode is calculated , and the calculation formula is: wherein, is the current opening degree of the water temperature associated opening degree in heating mode.

3. The control method of claim 1, wherein, The carbon dioxide heat pump system target pressure, carbon dioxide heat pump system current pressure and heating process PID parameter setting table are used to calculate the pressure-related opening degree in the heating mode The specific steps include: obtaining a pressure deviation value in the heating mode based on the difference between the target pressure of the carbon dioxide heat pump system in the heating mode and the current pressure of the carbon dioxide heat pump system; Based on the obtained pressure deviation value under the heating mode, and the corresponding PID parameter setting table for the heating process , and The value is used to calculate the pressure-related opening increment in heating mode. The calculation formula is: wherein, is an opening increment of the pressure-related opening in the heating mode, is is a pressure deviation value in the heating mode at the time point, is is a pressure deviation value in the heating mode at the time point, is is a pressure deviation value in the heating mode at the time point; Based on the calculated opening increment of the pressure-related opening degree in the heating mode and the current opening degree of the pressure-related opening degree in the heating mode, the pressure-related opening degree in the heating mode is calculated , and the calculation formula is: wherein, is the current opening degree of the pressure-dependent opening degree in heating mode.

4. The carbon dioxide heat pump air conditioner full-pass throttling valve control method of claim 1, wherein: The water temperature coefficient is less than the value of the optimal pressure coefficient .

5. The control method of claim 1, wherein, The specific steps of obtaining the opening degree of the ERV valve in the cooling mode based on the evaporation temperature correlation opening degree and the pressure correlation opening degree when the working mode of the carbon dioxide heat pump system is the cooling mode comprise: When the working mode of the carbon dioxide heat pump system is the cooling mode, based on the target evaporation temperature of the carbon dioxide heat pump system, the current evaporation temperature of the carbon dioxide heat pump system and the PID parameter setting table of the cooling process, the evaporation temperature correlation opening degree in the cooling mode is calculated , Based on the carbon dioxide heat pump system target system pressure, the carbon dioxide heat pump system current system pressure and the refrigeration process PID parameter setting table, the pressure correlation opening degree in the refrigeration mode is calculated ; based on the calculated evaporating temperature correlation opening degree in cooling mode and the corresponding evaporating temperature coefficient and the pressure correlation opening degree in refrigeration mode and the corresponding optimal pressure coefficient the opening degree of the ERV valve in refrigeration mode is calculated the calculation method is: based on the calculated opening of the erv valve in cooling mode A carbon dioxide heat pump system is controlled.

6. The control method of claim 5, wherein the full pass throttling valve is controlled to be opened when the carbon dioxide heat pump air conditioner is operated in the heating operation mode. The carbon dioxide heat pump system target evaporation temperature, carbon dioxide heat pump system current evaporation temperature and refrigeration process PID parameter setting table are used to calculate the evaporation temperature associated opening degree in the refrigeration mode The specific steps include: obtaining an evaporation temperature deviation value based on the difference between the target evaporation temperature of the carbon dioxide heat pump system in the cooling mode and the current evaporation temperature of the carbon dioxide heat pump system; Based on the obtained evaporation temperature deviation value and the corresponding PID parameter setting table for the refrigeration process , and The value is used to calculate the opening increment of the evaporator temperature-related opening in cooling mode. The calculation formula is: wherein, an opening increment of the opening degree associated with the evaporation temperature in the cooling mode, an evaporation temperature at the time point, an evaporation temperature at the time point, an evaporation temperature at the time point, an evaporation temperature at the time point, an evaporation temperature at the time point, an evaporation temperature at the time point. Based on the calculated opening increment of the evaporation temperature associated opening degree in the refrigeration mode and the current opening degree of the evaporation temperature associated opening degree in the refrigeration mode, the evaporation temperature associated opening degree in the refrigeration mode is calculated , and the calculation formula is: wherein, is the current opening degree for the evaporating temperature associated opening degree in cooling mode.

7. The control method of claim 5, wherein the full pass throttling valve is controlled by the controller to be opened when the temperature of the refrigerant in the condenser is higher than the temperature of the refrigerant in the evaporator. The carbon dioxide heat pump system target system pressure, carbon dioxide heat pump system current system pressure and refrigeration process PID parameter setting table are used to calculate the pressure-related opening degree in the refrigeration mode The specific calculation steps are as follows: obtaining a pressure deviation value in the cooling mode based on the difference between the target system pressure of the carbon dioxide heat pump system in the cooling mode and the current system pressure of the carbon dioxide heat pump system; Based on the obtained pressure deviation value under the cooling mode, and the corresponding PID parameter setting table for the cooling process , and The value is used to calculate the pressure-related opening increment in cooling mode. The calculation formula is: wherein, is an opening increment of the pressure correlation opening in the cooling mode, is is a pressure deviation value in the cooling mode at the time point, is is a pressure deviation value in the cooling mode at the time point, is is a pressure deviation value in the cooling mode at the time point; Based on the calculated opening increment of the pressure-correlated opening degree in the refrigeration mode and the current opening degree of the pressure-correlated opening degree in the refrigeration mode, the pressure-correlated opening degree in the refrigeration mode is calculated , and the calculation formula is: wherein, is the current opening degree of the pressure-dependent opening degree in the cooling mode.

8. The carbon dioxide heat pump air conditioner full-pass throttling valve control method of claim 5, wherein: The evaporation temperature coefficient is less than the value of the optimal pressure coefficient .

9. A control device for a carbon dioxide heat pump system air conditioner full opening throttling valve for implementing the steps of the carbon dioxide heat pump air conditioner full opening throttling valve control method according to any one of claims 1 to 8, characterized by, The method comprises: an obtaining module configured to obtain the working mode of the carbon dioxide heat pump system; an executing module configured to, according to the working mode obtained by the obtaining module, obtain the water temperature correlation opening degree and the pressure correlation opening degree based on the water temperature and the optimal system pressure of the carbon dioxide heat pump system when the working mode of the carbon dioxide heat pump system is the heating mode, and weight to obtain the opening degree of the ERV valve in the heating mode; and obtain the evaporation temperature correlation opening degree and the pressure correlation opening degree based on the evaporation temperature and the optimal system pressure of the carbon dioxide heat pump system when the working mode of the carbon dioxide heat pump system is the cooling mode, and weight to obtain the opening degree of the ERV valve in the cooling mode.

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