Control method for heat pump system, and heat pump system

Abstract

Disclosed in the present application are a control method for a heat pump system, and a heat pump system. The heat pump system comprises a compressor, a condenser, an economizer and an evaporator, wherein the condenser comprises a first refrigerant channel and a water channel; and the economizer comprises a second refrigerant channel and a third refrigerant channel. The control method comprises: starting a compressor, and regulating, to a preset flow rate, both the flow rate of a refrigerant which enters a third refrigerant channel and the flow rate of a refrigerant which enters an evaporator; acquiring the water output temperature and a set temperature value of a water channel of a condenser; and on the basis of the water output temperature and the set temperature value, controlling the rotational speed of the compressor, such that the water output temperature approaches the set temperature value. The rotational speed of a compressor is controlled by using a water output temperature and a set temperature value, so that the heat pump system promptly responds to changes in the water output temperature, thereby improving the accuracy of regulating the water output temperature, thus achieving a quick response to the requirements of users for the water output temperature, and improving the user experience.

Description

Control method of heat pump system and heat pump system TECHNICAL FIELD

[0001] The present application relates to the technical field of heat pump, in particular to a control method of heat pump system and heat pump system. BACKGROUND

[0002] The heat pump is based on the principle of reverse Carnot cycle, through the consumption of certain auxiliary energy (such as electric energy), using the refrigerant in the compressor, absorbing the low temperature heat in the environment into the refrigerant, and then releasing the high temperature heat to the space or working medium that needs to be heated through the condenser, so as to realize the purpose of transferring the heat energy of low temperature heat source to high temperature heat source.

[0003] At present, when hot water is prepared by using heat pump, the speed of the compressor is generally adjusted by the exhaust temperature of the compressor. However, the applicant finds that this method cannot respond to the change of outlet water temperature in time, resulting in poor accuracy of adjusting outlet water temperature, which affects the user experience. SUMMARY

[0004] The embodiments of the present application provide a control method of heat pump system and heat pump system, the speed of the compressor is controlled according to the outlet water temperature and temperature set value, so as to improve the accuracy of adjusting outlet water temperature.

[0005] In a first aspect, a control method of heat pump system is provided, the heat pump system comprises a compressor, a condenser, an economizer and an evaporator, the condenser comprises a first refrigerant passage and a water passage, the economizer comprises a second refrigerant passage and a third refrigerant passage, the control method comprises: starting the compressor in response to a starting instruction, adjusting the flow rate of the refrigerant entering the third refrigerant passage and the flow rate of the refrigerant entering the evaporator to a preset flow rate respectively; obtaining the outlet water temperature of the water passage of the condenser and a temperature set value; controlling the speed of the compressor according to the outlet water temperature and the temperature set value, so that the outlet water temperature approaches the temperature set value.

[0006] In some embodiments, the temperature set value is a set temperature value or a temperature value interval.

[0007] In some embodiments, the speed of the compressor is controlled according to the outlet water temperature and the temperature set value, comprising a first control mode and / or a second control mode, wherein: the first control mode comprises: if the outlet water temperature is less than a preset lower limit of temperature, increasing the speed of the compressor according to a preset speed change rate; if the outlet water temperature is greater than a preset upper limit of temperature, decreasing the speed of the compressor according to a preset speed change rate; the second control mode comprises: if the outlet water temperature is in a temperature value interval corresponding to the temperature set value, performing proportional integral derivative control on the speed of the compressor according to the outlet water temperature and the temperature set value.

[0008] In some embodiments, the heat pump system further comprises a first expansion valve and a second expansion valve, respectively adjusting the flow rate of the refrigerant entering the third refrigerant passage and the flow rate of the refrigerant entering the evaporator to a preset flow rate, comprising: adjusting the first expansion valve to a preset opening degree to adjust the flow rate of the refrigerant entering the third refrigerant passage to a preset flow rate; adjusting the second expansion valve to a preset opening degree to adjust the flow rate of the refrigerant entering the evaporator to a preset flow rate.

[0009] In some embodiments, further comprising: obtaining a first superheat degree of the refrigerant at the intermediate suction port of the compressor and a second superheat degree of the refrigerant at the inlet of the compressor; controlling the opening degree of the first expansion valve according to the first superheat degree and controlling the opening degree of the second expansion valve according to the second superheat degree.

[0010] In some embodiments, the heat pump system further comprises an adjusting assembly for adjusting the flow rate of the water passage, and after controlling the rotation speed of the compressor according to the outlet water temperature, further comprising: if the heat pump system enters a preset stable running state, obtaining a temperature setting value corresponding to the outlet water temperature; if the outlet water temperature decreases or the temperature setting value increases, first controlling the rotation speed of the compressor according to a first preset control mode, and then controlling the adjusting parameter of the adjusting assembly, different adjusting parameters corresponding to different flow rates of the water passage; if the outlet water temperature increases or the temperature setting value decreases, first controlling the adjusting parameter of the adjusting assembly according to a second preset control mode, and then controlling the rotation speed of the compressor.

[0011] In some embodiments, further comprising: if the adjusting parameter decreases to a preset minimum value and remains for a first time length, and the difference between the temperature setting value and the outlet water temperature is greater than a first difference value, or, if the rotation speed of the compressor decreases to a preset minimum rotation speed and remains for a second time length, and the difference between the outlet water temperature and the temperature setting value is greater than a second difference value, issuing an alarm information.

[0012] In some embodiments, first controlling the rotation speed of the compressor according to the first preset control mode, and then controlling the adjusting parameter of the adjusting assembly, comprises: increasing the rotation speed of the compressor based on a proportional-integral-derivative control mode; if the rotation speed of the compressor reaches a preset maximum rotation speed and remains for a third time length, and the difference between the temperature setting value and the outlet water temperature is greater than the first difference value, decreasing the adjusting parameter to reduce the flow rate of the water passage.

[0013] In some embodiments, the method further comprises: increasing the adjustment parameter to increase the flow rate of the water passage; if the adjustment parameter reaches a preset maximum value and remains unchanged for a fourth time length, and the difference between the outlet water temperature and the temperature set value is greater than the second difference, decreasing the rotation speed of the compressor based on a proportional-integral-derivative control mode.

[0014] In some embodiments, the adjustment component is a regulating valve and the adjustment parameter is an opening degree of the regulating valve, and / or the adjustment component is a pump and the adjustment parameter is a rotation speed of the pump.

[0015] In some embodiments, the method further comprises: after starting the compressor, monitoring an operation parameter of the compressor; and if the operation parameter of the compressor meets a preset shutdown condition, stopping the compressor; wherein the operation parameter of the compressor comprises at least one of an inlet air temperature, an outlet air temperature, an inlet air pressure, an outlet air pressure, an exhaust air temperature, an oil temperature, and an oil level.

[0016] In a second aspect, a heat pump system is provided, comprising at least a compressor, a condenser, an economizer, an evaporator, and a control unit, the condenser comprising a first refrigerant passage and a water passage, the economizer comprising a second refrigerant passage and a third refrigerant passage, two ends of the second refrigerant passage being respectively connected to the first refrigerant passage and the evaporator, two ends of the third refrigerant passage being respectively connected to the first refrigerant passage and an intermediate inlet of the compressor, the control unit being electrically connected to the compressor and the condenser, and configured to control a rotation speed of the compressor according to an outlet water temperature of the water passage of the condenser and a temperature set value.

[0017] In some embodiments, the heat pump system further comprises a subcooler, an inlet of the subcooler being connected to the first refrigerant passage, and an outlet of the subcooler being connected to the evaporator.

[0018] In some embodiments, the heat pump system further comprises a first electromagnetic valve, a second electromagnetic valve, a third electromagnetic valve, and a regulating valve, the first electromagnetic valve being arranged between the first refrigerant passage and the second refrigerant passage, the second electromagnetic valve and the third electromagnetic valve being arranged at the inlet and the outlet of the subcooler respectively, and the regulating valve being arranged at an outlet of the water passage.

[0019] In some embodiments, the heat pump system further comprises: a first temperature sensor arranged at an outlet of the water channel and configured to obtain the outlet water temperature; a second temperature sensor arranged between the third refrigerant channel and an intermediate inlet of the compressor and configured to obtain a first temperature of refrigerant at the intermediate inlet; a third temperature sensor arranged at an inlet of the compressor and configured to obtain a second temperature of refrigerant at the inlet of the compressor; a first pressure sensor arranged between the third refrigerant channel and the intermediate inlet of the compressor and configured to obtain a first pressure of refrigerant at the intermediate inlet; and a second pressure sensor arranged at the inlet of the compressor and configured to obtain a second pressure of refrigerant at the inlet of the compressor.

[0020] By applying the above technical solution, the outlet water temperature of the water channel of the condenser is obtained, and the rotating speed of the compressor is controlled according to the outlet water temperature, so that the heat pump system can respond to the change of the outlet water temperature in time, thereby improving the accuracy of adjusting the outlet water temperature, and further realizing fast response to the outlet water temperature requirement of the user and improving the user experience. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the present application, the drawings needed in the following embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments described in the present application, and other drawings can also be obtained according to these drawings without creative labor for those skilled in the art.

[0022] Fig. 1 is a flow chart of a control method of a heat pump system according to an embodiment of the present application;

[0023] Fig. 2 is a flow chart of adjusting the flow rate of refrigerant entering the third refrigerant channel and the flow rate of refrigerant entering the evaporator according to an embodiment of the present application;

[0024] Fig. 3 is a flow chart of controlling the opening degree of the first expansion valve and the second expansion valve according to an embodiment of the present application;

[0025] Fig. 4 is a flow chart of controlling the heat pump system according to the first preset control mode or the second preset control mode according to an embodiment of the present application;

[0026] Fig. 5 is a flow chart of first controlling the rotating speed of the compressor and then controlling the adjustment parameter of the adjustment assembly according to the first preset control mode according to an embodiment of the present application;

[0027] Fig. 6 is a flow chart of first controlling the adjustment parameter of the adjustment assembly and then controlling the rotating speed of the compressor according to the second preset control mode according to an embodiment of the present application;

[0028] Fig. 7 is a structural schematic diagram of a heat pump system according to an embodiment of the present application;

[0029] Fig. 8 is a schematic diagram of a heat pump system according to another embodiment of the present application;

[0030] Fig. 9 is a schematic diagram of a heat pump system according to yet another embodiment of the present application;

[0031] Fig. 10 is a schematic diagram of a control method of a heat pump system according to an embodiment of the present application;

[0032] Fig. 11 is a schematic diagram of a control method of a heat pump system according to an embodiment of the present application.

[0033] 1, compressor; 2, condenser; 3, economizer; 4, evaporator; 5, second expansion valve; 6, first expansion valve; 7, first pressure sensor; 8, second temperature sensor; 9, second pressure sensor; 10, third temperature sensor; 11, first temperature sensor; 12, regulating valve; 13, first solenoid valve; 14, subcooler; 15, second solenoid valve; 16, third solenoid valve; 17, oil line. DETAILED DESCRIPTION

[0034] Various aspects and features of the present application are described in this specification, and are demonstrated in the accompanying drawings.

[0035] It is to be understood that various alterations, modifications and improvements can be made to the embodiments of the present application described herein. Accordingly, the above description is not to be taken as limiting, but is merely as exemplification of the embodiments of the present application. Other modifications, being within the scope and spirit of the present application, will be readily apparent to those skilled in the art.

[0036] The accompanying drawings incorporated in and forming a part of the specification, illustrate embodiments of the present application and, together with the general description of the application given above, and the detailed description of the embodiments given below, serve to explain the principles of the present application.

[0037] These and other characteristics, features and advantages of the present application will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of non-limiting examples, the principles of the application.

[0038] It is also to be understood that the application is not limited in its application to the details set forth in the description contained herein or the examples cited and that the

[0039] The above and other aspects, features and advantages of the present application will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of non-limiting examples, the principles of the application.

[0040] Specific embodiments of the application are described herein with reference to the accompanying drawings. However, it will be understood that the application is not limited to these embodiments, but can be practiced with modification and alteration within the scope of the application. Accordingly, the specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and a representative basis for teaching one skilled in the art to variously employ the application.

[0041] The specification can use phrases such as "in one embodiment," "in another embodiment," "in yet another embodiment," or "in other embodiments," which can refer to one or more embodiments of the same or different embodiments of the application.

[0042] The control method of the heat pump system of the embodiment of the application uses the outlet water temperature and the temperature set value to control the rotation speed of the compressor, so that the heat pump system responds to the change of the outlet water temperature in time, thereby improving the accuracy of adjusting the outlet water temperature, and further realizing the rapid response to the outlet water temperature demand of the user and improving the user experience.

[0043] The heat pump system of the embodiment of the application comprises a compressor, a condenser, an economizer and an evaporator. The condenser comprises a first refrigerant passage and a water passage. The economizer comprises a second refrigerant passage and a third refrigerant passage. The two ends of the second refrigerant passage are respectively communicated with the first refrigerant passage and the evaporator. The two ends of the third refrigerant passage are respectively communicated with the first refrigerant passage and the intermediate gas inlet of the compressor. The circulation process of the refrigerant is as follows:

[0044] After the refrigerant is compressed by the compressor, it becomes a high-pressure and high-temperature gas (superheated state), and then enters the first refrigerant passage of the condenser (high-temperature side heat exchanger) through the exhaust pipe of the compressor. The gaseous refrigerant is condensed into a supercooled liquid in the condenser by heat exchange with the user water in the water passage of the condenser. The supercooled liquid is divided into auxiliary refrigerant and main refrigerant to enter the economizer for heat exchange. The auxiliary refrigerant becomes a medium-pressure (between the evaporation pressure and the condensation pressure) gas-liquid mixture after throttling expansion, and then enters the third refrigerant passage of the economizer, and becomes a medium-pressure gaseous vapor after heat exchange with the main refrigerant in the second refrigerant passage of the economizer, and then enters the intermediate gas inlet of the compressor (to realize the function of air supplement); the main refrigerant is cooled in the economizer, and the supercooling degree is increased, and then becomes a low-temperature and low-pressure gas-liquid mixture after throttling expansion, and then enters the evaporator to be gasified into a superheated vapor, and then enters the compressor through the suction pipe of the compressor, to complete the closed cycle.

[0045] As shown in FIG. 1, the control method comprises the following steps:

[0046] Step S101, in response to the start instruction, start the compressor, and adjust the flow rate of the refrigerant entering the third refrigerant passage and the flow rate of the refrigerant entering the evaporator to preset flow rates respectively.

[0047] In this embodiment, the start instruction can be issued by the user, for example, the user issues the start instruction through the remote controller or presses the power-on key, or the start instruction can be automatically triggered when the self-start condition is met, for example, the start instruction is automatically triggered at the scheduled power-on time. In response to the start instruction, the compressor is started, and the flow rate of the refrigerant entering the third refrigerant passage is adjusted to a preset flow rate to ensure that the intermediate suction port of the compressor has sufficient suction, and the flow rate of the refrigerant entering the evaporator is adjusted to a preset flow rate to ensure that the suction port of the compressor has sufficient suction.

[0048] Optionally, the compressor can be started according to the motor start frequency, for example, 30 Hz.

[0049] Optionally, the type of refrigerant can include any one of R22, R134a, R410A, R290, etc.

[0050] It should be noted that the preset flow rates in the embodiments of the present application can be the same flow rate value, or two different flow rate values, each flow rate value corresponding to the flow rate of the refrigerant entering the third refrigerant passage and the flow rate of the refrigerant entering the evaporator respectively.

[0051] Step S102, obtain the outlet water temperature of the water passage of the condenser and a temperature set value.

[0052] In this embodiment, a temperature sensor can be arranged at the outlet of the water passage to obtain the outlet water temperature. The temperature set value corresponds to the outlet water temperature, and the temperature set value can be determined according to the set value input by the user, or the temperature set value can be determined according to the operation mode selected by the user, for example, when the operation mode is a high-temperature mode, the temperature set value is 100℃, and when the operation mode is a medium-temperature mode, the temperature set value is 55℃. In addition, the temperature set value can be a temperature set value input by the user in real time, or a temperature set value set by the user in advance.

[0053] Step S103, control the speed of the compressor according to the outlet water temperature and the temperature set value, so that the outlet water temperature approaches the temperature set value.

[0054] In this embodiment, the compressor is a variable frequency compressor, and the speed of the compressor is changed by a frequency converter. After obtaining the outlet water temperature, the operating frequency of the frequency converter is controlled according to the outlet water temperature, and the speed of the compressor is controlled in turn. After obtaining the outlet water temperature and the temperature set value, the outlet water temperature and the temperature set value are compared, and the speed of the compressor is controlled according to the difference between the outlet water temperature and the temperature set value, so that the outlet water temperature approaches the temperature set value.

[0055] For example, if the outlet water temperature is 75℃ and the temperature setting value is 90℃, the outlet water temperature is increased to reach or approach 90℃ by controlling the rotation speed of the compressor. If the outlet water temperature reaches 95℃ due to the decrease of the user water consumption, and the temperature setting value is still 90℃, the outlet water temperature is decreased to 90℃ by controlling the rotation speed of the compressor. If the user water consumption increases again, resulting in the outlet water temperature being lower than the temperature setting value 90℃, the outlet water temperature is continuously increased by controlling the rotation speed of the compressor. If the outlet water temperature reaches 90℃, and the temperature setting value changes from 90℃ to 70℃, the outlet water temperature is decreased to 70℃ by controlling the rotation speed of the compressor. It can be seen that the rotation speed of the compressor is controlled according to the outlet water temperature and the temperature setting value, which can quickly respond to the different outlet water temperature requirements of the user, and realize more accurate outlet water temperature control.

[0056] In some embodiments of the present application, if the outlet water temperature is lower than the temperature setting value, the rotation speed of the compressor is increased, and if the outlet water temperature is higher than the temperature setting value, the rotation speed of the compressor is decreased, so that the rotation speed of the compressor can be more accurately controlled.

[0057] The control method of the heat pump system in the embodiments of the present application, the heat pump system comprising a compressor, a condenser, an economizer and an evaporator, the condenser comprising a first refrigerant passage and a water passage, the economizer comprising a second refrigerant passage and a third refrigerant passage, the control method comprising: starting the compressor in response to a starting instruction, adjusting the flow rate of the refrigerant entering the third refrigerant passage and the flow rate of the refrigerant entering the evaporator to a preset flow rate respectively; obtaining the outlet water temperature of the water passage of the condenser and a temperature setting value; and controlling the rotation speed of the compressor according to the outlet water temperature and the temperature setting value, so that the outlet water temperature approaches the temperature setting value. The rotation speed of the compressor is controlled according to the outlet water temperature and the temperature setting value, so that the heat pump system can respond to the change of the outlet water temperature in time, thereby improving the accuracy of adjusting the outlet water temperature, and further realizing the quick response to the outlet water temperature requirements of the user, and improving the user experience.

[0058] In some embodiments of the present application, the temperature setting value is a set temperature value or a temperature value interval.

[0059] In the embodiments, the temperature setting value can be a set temperature value or a set temperature value interval, thereby improving flexibility. For example, the temperature setting value can be 95℃, and the adjustment of the outlet water temperature is completed when the outlet water temperature reaches 95℃. The temperature setting value can also be 90±1℃, i.e. the temperature value interval is 89℃-91℃, and the adjustment of the outlet water temperature is completed when the outlet water temperature is not less than 89℃ and not more than 91℃.

[0060] In some embodiments of the present application, the rotating speed of the compressor is controlled according to the outlet water temperature and the temperature setting value, including a first control mode and / or a second control mode, wherein:

[0061] The first control mode includes:

[0062] If the outlet water temperature is less than a preset lower temperature limit, the rotating speed of the compressor is increased according to a preset rotating speed change rate;

[0063] If the outlet water temperature is greater than a preset upper temperature limit, the rotating speed of the compressor is decreased according to a preset rotating speed change rate;

[0064] The second control mode includes:

[0065] If the outlet water temperature is in a temperature value interval corresponding to the temperature setting value, the rotating speed of the compressor is controlled according to the outlet water temperature and the temperature setting value by proportional-integral-differential (PID) control.

[0066] In the embodiments, the rotating speed of the compressor can be controlled by the first control mode or the second control mode, or the first control mode and the second control mode can be used to control the rotating speed of the compressor in different situations.

[0067] For the first control mode, a preset lower temperature limit and a preset upper temperature limit are set in advance. If the outlet water temperature is less than the preset lower temperature limit, it indicates that the outlet water temperature is too low, and the rotating speed of the compressor is increased according to the preset rotating speed change rate. If the outlet water temperature is greater than the preset upper temperature limit, it indicates that the outlet water temperature is too high, and the rotating speed of the compressor is decreased according to the preset rotating speed change rate, so that the rotating speed of the compressor can be controlled more efficiently. For the second control mode, a temperature value interval corresponding to the temperature setting value is set in advance. If the outlet water temperature is in the temperature value interval, it indicates that the outlet water temperature is close to the temperature setting value, and the rotating speed of the compressor is controlled according to the outlet water temperature and the temperature setting value by PID control, so that the rotating speed of the compressor can be controlled more accurately.

[0068] Optionally, the temperature value interval can be determined by the preset lower temperature limit and the preset upper temperature limit, or by other temperature values different from the preset lower temperature limit and the preset upper temperature limit. In some embodiments, when the first control mode and the second control mode are used to control the rotating speed of the compressor, the temperature value interval is determined by the preset lower temperature limit and the preset upper temperature limit. The person skilled in the art can flexibly set different preset lower temperature limits, preset upper temperature limits and temperature value intervals according to actual needs, which are not limited in the embodiments of the present application.

[0069] By using the first control mode and / or the second control mode, the rotating speed of the compressor can be controlled more flexibly and efficiently.

[0070] In some embodiments of the present application, the heat pump system further comprises a first expansion valve and a second expansion valve, respectively adjusting the flow rate of the refrigerant entering the third refrigerant passage and the flow rate of the refrigerant entering the evaporator to a preset flow rate, as shown in FIG. 2, comprising the following steps:

[0071] Step S1011, adjusting the first expansion valve to a preset opening degree to adjust the flow rate of the refrigerant entering the third refrigerant passage to a preset flow rate.

[0072] In this embodiment, the expansion valve is used for throttling and flow control of the refrigerant, and the refrigerant becomes low-temperature and low-pressure wet steam after throttling through the expansion valve. The heat pump system comprises a first expansion valve and a second expansion valve, the first expansion valve can be arranged at the inlet of the third refrigerant passage, and by adjusting the first expansion valve to a preset opening degree, the flow rate of the refrigerant entering the third refrigerant passage is adjusted to a preset flow rate. The first expansion valve and the second expansion valve are both electronic expansion valves.

[0073] Step S1012, adjusting the second expansion valve to a preset opening degree to adjust the flow rate of the refrigerant entering the evaporator to a preset flow rate.

[0074] In this embodiment, the second expansion valve can be arranged at the inlet of the evaporator, and by adjusting the second expansion valve to a preset opening degree, the flow rate of the refrigerant entering the evaporator is adjusted to a preset flow rate.

[0075] It should be noted that the preset opening degree corresponding to the first expansion valve and the preset opening degree corresponding to the second expansion valve can be the same or different.

[0076] Through the first expansion valve and the second expansion valve, the flow rate of the refrigerant entering the third refrigerant passage and the flow rate of the refrigerant entering the evaporator are more accurately adjusted to a preset flow rate.

[0077] In some embodiments of the present application, as shown in FIG. 3, the method further comprises the following steps:

[0078] Step S104, obtaining the first superheat degree of the refrigerant at the intermediate suction port of the compressor and the second superheat degree of the refrigerant at the inlet of the compressor.

[0079] In this embodiment, the opening degrees of the first expansion valve and the second expansion valve are controlled by the superheat degrees at the corresponding positions respectively, so that the refrigerant entering the intermediate suction port and the inlet of the compressor is maintained at a suitable superheat degree, thereby ensuring the normal operation of the compressor. The first superheat degree of the refrigerant at the intermediate suction port of the compressor and the second superheat degree of the refrigerant at the inlet of the compressor can be obtained after the flow rate of the refrigerant entering the third refrigerant passage and the flow rate of the refrigerant entering the evaporator are respectively adjusted to a preset flow rate.

[0080] Step S105, controlling the opening degree of the first expansion valve according to the first superheat degree, and controlling the opening degree of the second expansion valve according to the second superheat degree.

[0081] After obtaining the first superheat degree and the second superheat degree, the opening degree of the first expansion valve is controlled according to the first superheat degree, so that the first superheat degree reaches the first superheat degree setting value, and the opening degree of the second expansion valve is controlled according to the second superheat degree, so that the second superheat degree reaches the second superheat degree setting value.

[0082] In the embodiment, by controlling the opening degrees of the first expansion valve and the second expansion valve according to the corresponding superheat degrees respectively, the normal operation of the compressor is ensured, and the stability of the heat pump system is improved.

[0083] In some embodiments of the present application, controlling the opening degree of the second expansion valve according to the second superheat degree comprises:

[0084] obtaining a second superheat degree setting value corresponding to the second superheat degree;

[0085] controlling the opening degree of the first expansion valve according to the second superheat degree and the second superheat degree setting value.

[0086] In the embodiment, the second superheat degree setting value is pre-set, and after obtaining the second superheat degree setting value, the opening degree of the second expansion valve is controlled according to the second superheat degree and the second superheat degree setting value. Specifically, when the second superheat degree is less than the second superheat degree setting value, the second expansion valve is closed by proportional-integral-derivative control, and when the second superheat degree is greater than the second superheat degree setting value, the second expansion valve is opened by proportional-integral-derivative control, so as to more accurately control the opening degree of the first expansion valve, so that the refrigerant at the inlet of the compressor is kept at a suitable superheat degree, and the operation stability of the compressor is improved.

[0087] In some embodiments of the present application, controlling the opening degree of the first expansion valve according to the first superheat degree comprises:

[0088] obtaining a first superheat degree setting value corresponding to the first superheat degree;

[0089] if the first superheat degree is less than the first superheat degree setting value, reducing the opening degree of the first expansion valve;

[0090] if the first superheat degree is greater than the first superheat degree setting value, increasing the opening degree of the first expansion valve.

[0091] In the embodiment, the first superheat degree setting value is preset, and after the first superheat degree setting value is obtained, the first superheat degree is compared with the first superheat degree setting value. If the first superheat degree is less than the first superheat degree setting value, the opening degree of the first expansion valve is reduced to increase the first superheat degree. If the first superheat degree is greater than the first superheat degree setting value, the opening degree of the first expansion valve is increased to reduce the first superheat degree, so that the opening degree of the first expansion valve is more efficiently controlled.

[0092] In some embodiments of the present application, as an alternative way of controlling the first expansion valve, the opening degree of the first expansion valve is controlled according to the first superheat degree, comprising:

[0093] obtaining a first superheat degree setting value corresponding to the first superheat degree;

[0094] proportionally integrating and differentiating controlling the opening degree of the first expansion valve according to the first superheat degree and the first superheat degree setting value.

[0095] In the embodiment, by obtaining the first superheat degree setting value, proportionally integrating and differentiating controlling the opening degree of the first expansion valve according to the first superheat degree and the first superheat degree setting value, the opening degree of the first expansion valve can be more accurately controlled, and the operation stability of the compressor is improved.

[0096] In some embodiments of the present application, the first superheat degree of the refrigerant at the intermediate inlet of the compressor and the second superheat degree of the refrigerant at the inlet of the compressor are obtained, comprising:

[0097] obtaining a first temperature and a first pressure of the refrigerant at the intermediate inlet;

[0098] determining the first superheat degree based on the first temperature and a first saturation temperature corresponding to the first pressure;

[0099] obtaining a second temperature and a second pressure of the refrigerant at the inlet;

[0100] determining the second superheat degree based on the second temperature and a second saturation temperature corresponding to the second pressure.

[0101] In the embodiment, the first temperature and the first pressure of the refrigerant at the intermediate inlet can be obtained by arranging a temperature sensor and a pressure sensor at the intermediate inlet of the compressor, and the second temperature and the second pressure of the refrigerant at the inlet can be obtained by arranging a temperature sensor and a pressure sensor at the inlet of the compressor. The first saturation temperature corresponding to the first pressure is obtained by looking up a table, and the first superheat degree is determined by subtracting the first saturation temperature from the first temperature. The second saturation temperature corresponding to the second pressure is obtained by looking up a table, and the second superheat degree is determined by subtracting the second saturation temperature from the second temperature, so that the first superheat degree and the second superheat degree are accurately determined.

[0102] In some embodiments of the present application, the heat pump system further comprises an adjusting assembly for adjusting the flow of the water channel, and after the speed of the compressor is controlled according to the outlet water temperature, the following steps are further included, as shown in FIG. 4:

[0103] In step S106, if the heat pump system enters a preset stable running state, a temperature setting value corresponding to the outlet water temperature is obtained.

[0104] In the present embodiment, the preset stable state can be that the outlet water temperature enters a stable state, for example, if the absolute value of the difference between the outlet water temperature and the temperature setting value is less than a preset difference value and remains less than the preset difference value for a preset time length, it is determined that the heat pump system enters the preset stable running state. The preset stable state can also be that the compressor enters a stable state, for example, if the fluctuation value of the speed of the compressor within a preset time length is less than a preset threshold value, it is determined that the heat pump system enters the preset stable running state. The preset stable state can also be that both the outlet water temperature and the compressor enter a stable state.

[0105] After the heat pump system enters the preset stable running state, the temperature setting value corresponding to the outlet water temperature is obtained, and subsequently, step S107 or step S108 is executed according to the change of the outlet water temperature or the temperature setting value. The temperature setting value can be determined according to the setting value input by the user, or the temperature setting value can be determined according to the running mode selected by the user, for example, when the running mode is a high-temperature mode, the temperature setting value is 85°C, and when the running mode is a medium-temperature mode, the temperature setting value is 55°C. In addition, the temperature setting value can be a temperature setting value input by the user in real time, or a temperature setting value set by the user in advance.

[0106] In step S107, if the outlet water temperature decreases or the temperature setting value increases, the speed of the compressor is first controlled according to a first preset control mode, and then the adjusting parameter of the adjusting assembly is controlled, and different adjusting parameters correspond to different flows of the water channel.

[0107] In the present embodiment, the heat pump system comprises an adjusting assembly for adjusting the flow of the water channel, and when the water consumption of the user increases, the outlet water temperature can be reduced. If the outlet water temperature decreases or the temperature setting value increases, the outlet water temperature needs to be increased. Specifically, the speed of the compressor is first controlled according to the first preset control mode, which can quickly increase the outlet water temperature. If the outlet water temperature still cannot meet the heat demand after the speed of the compressor is controlled, the adjusting parameter of the adjusting assembly is controlled to increase the outlet water temperature by controlling the outlet water flow.

[0108] In step S108, if the outlet water temperature increases or the temperature setting value decreases, the adjusting parameter of the adjusting assembly is first controlled according to a second preset control mode, and then the speed of the compressor is controlled.

[0109] In the embodiment, when the user's water consumption decreases, the outlet water temperature can be increased; if the outlet water temperature increases or the temperature set value decreases, the outlet water temperature needs to be reduced. Specifically, according to the second preset control mode, the adjustment parameter of the adjustment assembly is controlled first, that is, the outlet water temperature is reduced by controlling the outlet water flow; if the adjustment parameter of the adjustment assembly is controlled and the outlet water temperature still cannot be reduced to the appropriate temperature, the speed of the compressor is controlled to reduce the outlet water temperature.

[0110] By controlling the speed of the compressor and the adjustment parameter of the adjustment assembly according to the first preset control mode or the second preset control mode after the heat pump system enters the preset stable running state, when the outlet water temperature needs to be increased, the speed of the compressor is controlled first, so that the outlet water temperature can be quickly increased, and the water supply of the heating end can be maximally ensured. When the outlet water temperature needs to be reduced, the outlet water flow is controlled first, so that the outlet water temperature can be stably reduced, and the maximum flow of the heating end can be obtained, and the outlet water temperature can be efficiently and stably controlled.

[0111] In some embodiments of the present application, the method further comprises:

[0112] If the adjustment parameter is reduced to a preset minimum value and remains unchanged for a first time length, and the difference between the temperature set value and the outlet water temperature is greater than a first difference, or if the speed of the compressor is reduced to a preset minimum speed and remains unchanged for a second time length, and the difference between the outlet water temperature and the temperature set value is greater than a second difference, an alarm information is sent.

[0113] In the embodiment, after step S107 is performed, if the adjustment parameter is reduced to a preset minimum value and remains unchanged for a first time length, and the difference between the temperature set value and the outlet water temperature is greater than a first difference, it indicates that the outlet water temperature cannot be continuously increased, and an alarm information is sent to remind the user to check whether there is an abnormality in time. After step S108 is performed, if the speed of the compressor is reduced to a preset minimum speed and remains unchanged for a second time length, and the difference between the outlet water temperature and the temperature set value is greater than a second difference, it indicates that the outlet water temperature cannot be continuously reduced, and an alarm information is sent to remind the user to check whether there is an abnormality in time.

[0114] Optionally, the form of the alarm information can be one or a combination of several of the following: sound and light alarm, text, picture, audio, and video.

[0115] It should be noted that the first time length and the second time length can be equal or not equal, and the first difference and the second difference can be equal or not equal, which can be flexibly set by a person skilled in the art according to actual conditions.

[0116] By sending an alarm information when the outlet water temperature cannot be continuously adjusted, the user experience is improved.

[0117] In some embodiments of the present application, the rotational speed of the compressor is first controlled according to a first preset control mode, and then the adjustment parameter of the adjustment assembly is controlled, as shown in FIG. 5, including the following steps:

[0118] In step S1071, the rotational speed of the compressor is increased based on a proportional-integral-derivative control mode.

[0119] In the first preset control mode, the rotational speed of the compressor is increased based on a proportional-integral-derivative control mode according to the temperature set value to increase the outlet water temperature. The rotational speed of the compressor can be increased once or multiple times according to the change of the outlet water temperature. For example, if the outlet water temperature meets the heat demand after the rotational speed is increased once, the rotational speed is not increased again. If the outlet water temperature does not meet the heat demand, the rotational speed is increased again.

[0120] In step S1072, if the rotational speed of the compressor reaches a preset maximum rotational speed and is maintained for a third time length, and the difference between the temperature set value and the outlet water temperature is greater than the first difference, the adjustment parameter is decreased to reduce the flow of the water channel.

[0121] In the present embodiment, if the rotational speed of the compressor reaches a preset maximum rotational speed and is maintained for a third time length, and the difference between the temperature set value and the outlet water temperature is greater than the first difference, it is indicated that the rotational speed of the compressor cannot be increased any more. In order to further increase the outlet water temperature, the adjustment parameter is continuously decreased to reduce the flow of the water channel.

[0122] It can be understood that if the rotational speed of the compressor does not meet the condition of reaching a preset maximum rotational speed and being maintained for a third time length, or the difference between the temperature set value and the outlet water temperature is not greater than the first difference, the adjustment parameter is maintained unchanged.

[0123] When it is necessary to increase the outlet water temperature, the rotational speed of the compressor is first controlled by the first preset control mode, so that the outlet water temperature can be quickly increased, and the water supply of the heating end is maximally ensured.

[0124] In some embodiments of the present application, the adjustment parameter of the adjustment assembly is first controlled according to a second preset control mode, and then the rotational speed of the compressor is controlled, as shown in FIG. 6, including the following steps:

[0125] In step S1081, the adjustment parameter is increased to increase the flow of the water channel.

[0126] In the present embodiment, in the second preset control mode, the adjustment parameter is first increased to increase the flow of the water channel, and then the outlet water temperature is reduced. In order to ensure the stability of the system, the adjustment parameter is increased once or multiple times at a preset step length. For example, if the outlet water temperature is reduced to a suitable temperature after the adjustment parameter is increased once, the adjustment parameter is not increased again. If the outlet water temperature is not reduced to a suitable temperature, the adjustment parameter is increased again.

[0127] In step S1082, if the adjustment parameter reaches the preset maximum value and remains unchanged for the fourth time length, and the difference between the outlet water temperature and the temperature setting value is greater than the second difference value, the speed of the compressor is reduced based on the temperature setting value according to a proportional-integral-derivative control mode.

[0128] In this embodiment, if the adjustment parameter reaches the preset maximum value and remains unchanged for the fourth time length, and the difference between the outlet water temperature and the temperature setting value is greater than the second difference value, it indicates that the adjustment parameter cannot be continuously increased, and in order to further reduce the outlet water temperature, the speed of the compressor is continuously reduced based on the temperature setting value according to a proportional-integral-derivative control mode.

[0129] It can be understood that if the adjustment parameter does not satisfy the condition of reaching the preset maximum value and remaining unchanged for the fourth time length, or the difference between the outlet water temperature and the temperature setting value is greater than the second difference value, the speed of the compressor remains unchanged.

[0130] When it is necessary to reduce the outlet water temperature, the outlet water flow is preferentially controlled, the outlet water temperature can be stably reduced, and the maximum flow can be obtained by using the heating end.

[0131] Optionally, the third time length and the fourth time length can be equal or not equal, and can be flexibly set by those skilled in the art according to actual conditions.

[0132] In some embodiments of the present application, the adjustment assembly is a regulating valve and the adjustment parameter is the opening degree of the regulating valve, and / or the adjustment assembly is a pump and the adjustment parameter is the speed of the pump.

[0133] In this embodiment, the adjustment assembly can be a regulating valve and / or a pump that is in communication with the water channel. When the adjustment assembly is a regulating valve, the adjustment parameter is the opening degree of the regulating valve. When the adjustment assembly is a pump, the adjustment parameter is the speed of the pump. When the adjustment assembly is a regulating valve and a pump, the adjustment parameter is the opening degree of the regulating valve and the speed of the pump. For example, when the opening degree of the regulating valve reaches a preset maximum opening degree and the speed of the pump reaches a preset maximum speed, the adjustment parameter reaches a preset maximum value. When the opening degree of the regulating valve is reduced to a preset minimum opening degree and the speed of the pump is reduced to a preset minimum speed, the adjustment parameter is a preset minimum value. The regulating valve and the pump can be controlled synchronously or sequentially.

[0134] By taking the regulating valve and / or the pump as the adjustment assembly, more flexible and efficient control of the outlet water flow is achieved.

[0135] In some embodiments of the present application, before the speed of the compressor is controlled according to the outlet water temperature, the method further comprises:

[0136] The compressor is controlled to operate at a preset starting speed for a preset time length.

[0137] In this embodiment, the frequency of the frequency converter corresponding to the preset starting rotating speed can be 30 Hz, and the preset time length can be 15 s.

[0138] In some embodiments of the present application, after starting the compressor, further comprising:

[0139] monitoring an operating parameter of the compressor;

[0140] if the operating parameter of the compressor meets a preset shutdown condition, shutting down the compressor;

[0141] The operating parameter of the compressor includes at least one of an inlet air temperature, an outlet air temperature, an inlet air pressure, an outlet air pressure, an exhaust air temperature, an oil temperature, and an oil level.

[0142] In this embodiment, after starting the compressor, the operating parameter of the compressor is monitored, and when the preset shutdown condition is met, the compressor can be immediately shut down, thereby ensuring that the compressor is shut down in time after an abnormality occurs, or the compressor is shut down after a preset time length, avoiding frequent starting and stopping of the compressor and prolonging the service life of the compressor.

[0143] The present application also provides a heat pump system, as shown in FIG. 7, which at least includes a compressor 1, a condenser 2, a first expansion valve 6, an economizer 3, a second expansion valve 5, an evaporator 4, and a control unit. The condenser 2 includes a first refrigerant passage and a water passage. The economizer 3 includes a second refrigerant passage and a third refrigerant passage. The two ends of the second refrigerant passage are respectively connected to the first refrigerant passage and the evaporator 4. The two ends of the third refrigerant passage are respectively connected to the first refrigerant passage and an intermediate suction port of the compressor 1. The control unit is electrically connected to the compressor 1 and the condenser 2, and is configured to control the rotating speed of the compressor 1 according to the outlet water temperature of the water passage and a temperature setting value.

[0144] In this embodiment, the refrigerant is compressed by the compressor 1 into a high-pressure and high-temperature gas, and then enters the first refrigerant passage of the condenser 2 through the exhaust pipe of the compressor 1 to exchange heat with the user water in the water passage of the condenser 2. The gaseous refrigerant is condensed into a supercooled liquid in the condenser 2, and the supercooled liquid is divided into auxiliary refrigerant and main refrigerant to enter the economizer 3 for heat exchange. The auxiliary refrigerant is throttled and expanded by the first expansion valve 6 into a medium-pressure gas-liquid mixture, and then enters the third refrigerant passage of the economizer 3 to exchange heat with the main refrigerant in the second refrigerant passage of the economizer 3, thereby becoming a medium-pressure gaseous vapor, and then entering the intermediate suction port of the compressor 1. The main refrigerant is cooled in the economizer 3 to increase the supercooling degree, and then is throttled and expanded by the second expansion valve 5 into a low-temperature and low-pressure gas-liquid mixture, and then enters the evaporator 4 to be gasified into a superheated vapor, and then enters the compressor 1 through the suction pipe of the compressor 1, thereby completing the closed cycle.

[0145] After starting the compressor 1, the flow of refrigerant into the third refrigerant passage is adjusted to a preset flow by the first expansion valve 6 to ensure sufficient intake of the compressor 1 at the intermediate suction port, and the flow of refrigerant into the evaporator 4 is adjusted to a preset flow by the second expansion valve 5 to ensure sufficient intake of the compressor 1 at the suction port. The compressor 1 is a variable frequency compressor 1, and the speed of the compressor 1 is changed by a frequency converter. After the control unit obtains the outlet water temperature and the temperature set value, the operating frequency of the frequency converter is adjusted according to the outlet water temperature and the temperature set value, and then the speed of the compressor 1 is controlled.

[0146] The heat pump system of the embodiment of the present application controls the speed of the compressor 1 according to the outlet water temperature of the water passage by the control unit, so that the heat pump system responds to the change of the outlet water temperature in time, thereby improving the accuracy of adjusting the outlet water temperature, and then realizing fast response to the outlet water temperature requirement of the user and improving the user experience.

[0147] In some embodiments of the present application, the first expansion valve 6 is arranged between the first refrigerant passage and the third refrigerant passage, and the second expansion valve 5 is arranged between the second refrigerant passage and the evaporator 4.

[0148] In the embodiment, the first expansion valve 6 is arranged between the first refrigerant passage and the third refrigerant passage, and can throttle the refrigerant flowing out of the first refrigerant passage to become low-temperature and low-pressure wet steam before entering the third refrigerant passage. The second expansion valve 5 is arranged between the second refrigerant passage and the evaporator 4, and can throttle the refrigerant flowing out of the second refrigerant passage to become low-temperature and low-pressure wet steam before entering the evaporator 4.

[0149] In some embodiments of the present application, as shown in FIG. 8, the heat pump system further comprises a subcooler 14, the inlet of the subcooler 14 is communicated with the first refrigerant passage, and the outlet of the subcooler 14 is communicated with the evaporator 4.

[0150] In the embodiment, the subcooler 14 mainly reduces the flash gas generated during or after throttling by reducing the temperature of the refrigerant, thereby improving the efficiency of the heat pump system. The structure type of the subcooler 14 can be a jacketed tube type, a spray type, a plate heat exchanger, etc.

[0151] In some embodiments of the present application, as shown in FIG. 9, the heat pump system further comprises a first electromagnetic valve 13, a second electromagnetic valve 15, a third electromagnetic valve 16 and an adjusting valve 12, the first electromagnetic valve 13 is arranged between the first refrigerant passage and the second refrigerant passage, the second electromagnetic valve 15 and the third electromagnetic valve 16 are arranged at the inlet and the outlet of the subcooler 14 respectively, and the adjusting valve 12 is arranged at the outlet of the water passage.

[0152] In the embodiment, the first electromagnetic valve 13 is arranged to open and close the economizer 3, the second electromagnetic valve 15 and the third electromagnetic valve 16 are arranged to open and close the subcooler 14, and the adjusting valve 12 is arranged to accurately control the water flow rate of the water passage.

[0153] Optionally, the adjusting valve 12 can also be arranged at the inlet of the water passage.

[0154] In some embodiments of the present application, as shown in FIGS. 8 and 9, the heat pump system further comprises:

[0155] The first temperature sensor 11 is arranged at the outlet of the water passage to obtain the outlet water temperature;

[0156] The second temperature sensor 8 is arranged between the third refrigerant passage and the intermediate inlet of the compressor 1 to obtain the first temperature of the refrigerant at the intermediate inlet;

[0157] The third temperature sensor 10 is arranged at the inlet of the compressor 1 to obtain the second temperature of the refrigerant at the inlet of the compressor 1;

[0158] The first pressure sensor 7 is arranged between the third refrigerant passage and the intermediate inlet of the compressor 1 to obtain the first pressure of the refrigerant at the intermediate inlet;

[0159] The second pressure sensor 9 is arranged at the inlet of the compressor 1 to obtain the second pressure of the refrigerant at the inlet of the compressor 1.

[0160] In the embodiment, the first temperature sensor 11 is arranged to accurately obtain the outlet water temperature. The second temperature sensor 8 and the first pressure sensor 7 are arranged to accurately obtain the first temperature and the first pressure of the refrigerant at the intermediate inlet of the compressor 1, and thus the first superheat degree can be determined. The third temperature sensor 10 and the second pressure sensor 9 are arranged to accurately obtain the second temperature and the second pressure of the refrigerant at the inlet of the compressor 1, and thus the second superheat degree can be determined.

[0161] In some embodiments of the present application, as shown in FIG. 9, the economizer 3 further comprises an oil passage, and the two ends of the oil passage are communicated with the oil passage 17 of the compressor 1 to cool the oil in the oil passage 17.

[0162] In the embodiment, the oil passage 17 of the compressor 1 contains working oil for lubricating and cooling the compressor 1. The oil in the oil passage 17 enters the oil passage of the economizer 3 to exchange heat with the refrigerant in the third refrigerant passage, and then returns to the oil passage 17 from the oil passage of the economizer 3, so as to cool the oil in the oil passage 17. Thus, a separate oil cooler for the oil passage 17 can be avoided, and the cost is reduced.

[0163] To further illustrate the technical idea of the present application, the technical solutions of the present application will be described in conjunction with specific application scenarios.

[0164] The embodiment of the present application provides a control method of a heat pump system, as shown in Figure 7, the heat pump system comprises a compressor 1, a condenser 2, an economizer 3 and an evaporator 4, the condenser 2 comprises a first refrigerant passage and a water passage, the economizer 3 comprises a second refrigerant passage and a third refrigerant passage, two ends of the second refrigerant passage are respectively communicated with the first refrigerant passage and the evaporator 4, two ends of the third refrigerant passage are respectively communicated with the first refrigerant passage and an intermediate gas inlet of the compressor 1, a first expansion valve 6 is arranged between the first refrigerant passage and the third refrigerant passage, and a second expansion valve 5 is arranged between the second refrigerant passage and the evaporator 4. A first temperature sensor 11 and an adjusting valve 12 are arranged at the outlet of the water passage, a second temperature sensor 8 and a first pressure sensor 7 are arranged between the third refrigerant passage and the intermediate gas inlet of the compressor 1, and a third temperature sensor 10 and a second pressure sensor 9 are arranged at the inlet of the compressor 1.

[0165] The control method comprises the following processes:

[0166] In response to the instruction, the compressor 1 is started, and the first expansion valve 6 and the second expansion valve 5 are opened to a preset opening degree, such as 50% opening degree. As shown in Figure 10, on the one hand, after the compressor 1 is started, the compressor 1 is kept running at a preset starting speed for a preset time length, for example, the frequency converter of the compressor is kept running at 30Hz for 25s, then the outlet water temperature of the water passage is acquired through the first temperature sensor 11, if the outlet water temperature is less than a preset lower limit of temperature, the speed of the compressor 1 is increased at a preset speed change rate, if the outlet water temperature is greater than a preset upper limit of temperature, the speed of the compressor 1 is decreased at a preset speed change rate, and if the outlet water temperature is in a temperature value region (not less than the preset lower limit of temperature and not greater than the preset upper limit of temperature), PID control is performed according to the outlet water temperature and a temperature setting value.

[0167] On the other hand, the first temperature and the first pressure of the refrigerant at the intermediate gas inlet of the compressor 1 are respectively acquired through the second temperature sensor 8 and the first pressure sensor 7, the difference between the first temperature and the first saturation temperature corresponding to the first pressure is determined as the first superheat degree. The second temperature and the second pressure of the refrigerant at the inlet of the compressor 1 are respectively acquired through the third temperature sensor 10 and the second pressure sensor 9, the difference between the second temperature and the second saturation temperature corresponding to the second pressure is determined as the second superheat degree. For the second expansion valve 5, the opening degree of the second expansion valve 5 is controlled by PID according to the second superheat degree and a second superheat degree setting value. For the first expansion valve 6, if the first superheat degree is greater than a first superheat degree setting value, the opening degree of the first expansion valve 6 is increased, and if the first superheat degree is less than the first superheat degree setting value, the opening degree of the first expansion valve 6 is decreased.

[0168] If the absolute value of the difference between the outlet water temperature and the temperature set value is less than the preset difference value, and remains not less than the preset time length, it is determined that the heat pump system enters a preset stable operation state. As shown in FIG. 11, if the heat pump system enters the preset stable operation state, control is performed according to the first preset control mode or the second preset control mode. In FIG. 11, T represents the outlet water temperature, T_set represents the temperature set value, offset start is the first threshold value, offset2 is the second threshold value, offset start is greater than offset2, and Abs represents taking an absolute value.

[0169] It is determined whether Abs(T-T_set)>offset start, if yes, it is determined whether T>T_set, if no, the newly obtained T and T_set are inputted, and it is continuously determined whether Abs(T-T_set)>offset start.

[0170] If T≤T_set, the first preset control mode is entered to increase T. Specifically, according to T_set, the speed of the compressor 1 is increased in a PID control mode, if the speed of the compressor 1 reaches a preset maximum speed, and remains the preset maximum speed after a preset time length, and T_set-T>offset2, the opening degree of the adjusting valve 12 is decreased, if the opening degree of the adjusting valve 12 is decreased to a minimum opening degree, remains the minimum opening degree after a preset time length, and T_set-T>offset2, an alarm information is sent out.

[0171] If T>T_set, the second preset control mode is entered to decrease T. Specifically, the opening degree of the adjusting valve 12 is increased to increase the flow of the water passage, if the adjusting valve 12 is fully opened and remains fully opened after a preset time length, and T-T_set>offset2, the speed of the compressor 1 is decreased according to the temperature set value in a PID control mode, if the speed of the compressor 1 is decreased to a preset minimum speed, remains the preset minimum speed after a preset time length, and T-T_set>offset2, an alarm information is sent out.

[0172] By controlling the speed of the compressor and the opening degree of the adjusting valve according to the first preset control mode or the second preset control mode after the heat pump system enters the preset stable operation state, when it is needed to increase the outlet water temperature, the speed of the compressor is controlled preferentially, the outlet water temperature can be quickly increased, and the water supply of the heating end can be maximally ensured. When it is needed to decrease the outlet water temperature, the outlet water flow is controlled preferentially, the outlet water temperature can be stably decreased, the maximum flow of the heating end can be obtained, the outlet water temperature is efficiently and stably controlled, and when the outlet water temperature cannot be continuously adjusted, an alarm information is sent out to remind the user, and the user experience is improved.

[0173] In the above embodiments, all or part of the embodiments can be implemented by software, hardware, firmware or any combination thereof. When implemented by software, all or part of the embodiments can be implemented in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present application are generated. The computer can be a general purpose computer, a special purpose computer, a computer network, or other programmable apparatus. The computer instructions can be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another computer readable storage medium, for example, the computer instructions can be transmitted from one website, computer, server or data center to another website, computer, server or data center through wired (such as coaxial cable, optical fiber, digital subscriber line) or wireless (such as infrared, wireless, microwave, etc.) manner. The computer readable storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. integrated with one or more available media. The available media can be magnetic media (for example, floppy disk, hard disk, magnetic tape), optical media (for example, DVD), or semiconductor media (for example, solid state disk) and the like.

[0174] The above embodiments are only exemplary embodiments of the present application, and are not intended to limit the present application. The protection scope of the present application is defined by the claims. Those skilled in the art can make various modifications or equivalent replacements to the present application within the spirit and protection scope of the present application, and such modifications or equivalent replacements shall also be considered to fall within the protection scope of the present application.

Claims

1. A control method of a heat pump system including a compressor, a condenser, an economizer, and an evaporator, characterized by, The condenser comprises a first refrigerant passage and a water passage, the economizer comprises a second refrigerant passage and a third refrigerant passage, and the control method comprises: in response to a start instruction, starting the compressor, and adjusting the flow rates of the refrigerant entering the third refrigerant passage and the refrigerant entering the evaporator to preset flow rates, respectively; obtaining the outlet water temperature of the water passage of the condenser and a temperature set value; controlling the rotation speed of the compressor according to the outlet water temperature and the temperature set value, so that the outlet water temperature approaches the temperature set value.

2. The control method of a heat pump system according to claim 1, characterized by, The temperature set value is a set temperature value or a temperature value interval.

3. The control method of a heat pump system according to claim 1, characterized by, The control of the rotation speed of the compressor according to the outlet water temperature and the temperature set value comprises a first control mode and / or a second control mode, wherein: the first control mode comprises: if the outlet water temperature is less than a preset lower temperature limit, increasing the rotation speed of the compressor according to a preset rotation speed change rate; if the outlet water temperature is greater than a preset upper temperature limit, decreasing the rotation speed of the compressor according to a preset rotation speed change rate; the second control mode comprises: if the outlet water temperature is in a temperature value interval corresponding to the temperature set value, performing proportional-integral-derivative control on the rotation speed of the compressor according to the outlet water temperature and the temperature set value.

4. The control method of a heat pump system according to claim 1, characterized by, The heat pump system further comprises a first expansion valve and a second expansion valve, and the adjustment of the flow rates of the refrigerant entering the third refrigerant passage and the refrigerant entering the evaporator to preset flow rates comprises: adjusting the first expansion valve to a preset opening degree to adjust the flow rate of the refrigerant entering the third refrigerant passage to a preset flow rate; adjusting the second expansion valve to a preset opening degree to adjust the flow rate of the refrigerant entering the evaporator to a preset flow rate.

5. The control method of a heat pump system according to claim 4, characterized by, Further comprising: obtaining a first superheat degree of the refrigerant at an intermediate suction port of the compressor and a second superheat degree of the refrigerant at an inlet of the compressor; controlling the opening degree of the first expansion valve according to the first superheat degree and controlling the opening degree of the second expansion valve according to the second superheat degree.

6. The control method of a heat pump system according to claim 1, characterized by, The heat pump system further comprises an adjusting assembly for adjusting the flow rate of the water passage, and after the control of the rotation speed of the compressor according to the outlet water temperature, further comprising: if the heat pump system enters a preset stable running state, obtaining a temperature set value corresponding to the outlet water temperature; if the outlet water temperature decreases or the temperature set value increases, first controlling the rotation speed of the compressor according to a first preset control mode, and then controlling an adjusting parameter of the adjusting assembly, different adjusting parameters corresponding to different flow rates of the water passage; if the outlet water temperature increases or the temperature set value decreases, first controlling the adjusting parameter of the adjusting assembly according to a second preset control mode, and then controlling the rotation speed of the compressor.

7. The control method of a heat pump system according to claim 6, characterized by, Further comprising: if the adjusting parameter decreases to a preset minimum value and remains unchanged for a first time length, and the difference between the temperature set value and the outlet water temperature is greater than a first difference value, or if the rotation speed of the compressor decreases to a preset minimum rotation speed and remains unchanged for a second time length, and the difference between the outlet water temperature and the temperature set value is greater than a second difference value, an alarm information is sent.

8. The control method of a heat pump system according to claim 6, characterized by, According to a first preset control mode, the rotation speed of the compressor is controlled first, and then the adjustment parameter of the adjustment assembly is controlled, including: Increasing the rotation speed of the compressor based on a proportional-integral-derivative control mode; If the rotation speed of the compressor reaches a preset maximum rotation speed and remains unchanged for a third time length, and the difference between the temperature set value and the outlet water temperature is greater than the first difference, the adjustment parameter is decreased to reduce the flow of the water passage.

9. The control method of a heat pump system according to claim 6, characterized by, According to a second preset control mode, the adjustment parameter of the adjustment assembly is controlled first, and then the rotation speed of the compressor is controlled, including: Increasing the adjustment parameter to increase the flow of the water passage; If the adjustment parameter reaches a preset maximum value and remains unchanged for a fourth time length, and the difference between the outlet water temperature and the temperature set value is greater than the second difference, the rotation speed of the compressor is decreased based on a proportional-integral-derivative control mode.

10. The control method of a heat pump system according to any one of claims 6 to 9, characterized in that, The adjustment assembly is an adjustment valve and the adjustment parameter is the opening degree of the adjustment valve, and / or the adjustment assembly is a pump and the adjustment parameter is the rotation speed of the pump.

11. The control method of a heat pump system according to claim 1, characterized by, After starting the compressor, further comprising: Monitoring the operating parameter of the compressor; If the operating parameter of the compressor meets a preset shutdown condition, stopping the operation of the compressor; The operating parameter of the compressor includes at least one of the inlet air temperature, the outlet air temperature, the inlet air pressure, the outlet air pressure, the exhaust air temperature, the oil temperature and the oil level.

12. A heat pump system, characterized by At least comprising a compressor, a condenser, an economizer, an evaporator and a control unit, the condenser comprising a first refrigerant passage and a water passage, the economizer comprising a second refrigerant passage and a third refrigerant passage, two ends of the second refrigerant passage being respectively communicated with the first refrigerant passage and the evaporator, two ends of the third refrigerant passage being respectively communicated with the first refrigerant passage and an intermediate inlet of the compressor, the control unit being electrically connected with the compressor and the condenser, and being used for controlling the rotation speed of the compressor according to the outlet water temperature of the water passage of the condenser and a temperature set value.

13. The heat pump system of claim 12, wherein, The heat pump system further comprises a supercooler, an inlet of the supercooler being communicated with the first refrigerant passage, and an outlet of the supercooler being communicated with the evaporator.

14. The heat pump system of claim 13, wherein, The heat pump system further comprises a first electromagnetic valve, a second electromagnetic valve, a third electromagnetic valve and an adjustment valve, the first electromagnetic valve being arranged between the first refrigerant passage and the second refrigerant passage, the second electromagnetic valve and the third electromagnetic valve being arranged at the inlet and the outlet of the supercooler respectively, and the adjustment valve being arranged at the outlet of the water passage.

15. The heat pump system of claim 12, wherein, The heat pump system further comprises: A first temperature sensor arranged at the outlet of the water passage and used for acquiring the outlet water temperature; A second temperature sensor arranged between the third refrigerant passage and the intermediate inlet of the compressor and used for acquiring a first temperature of refrigerant at the intermediate inlet; A third temperature sensor arranged at the inlet of the compressor and used for acquiring a second temperature of refrigerant at the inlet of the compressor; A first pressure sensor arranged between the third refrigerant passage and the intermediate inlet of the compressor and used for acquiring a first pressure of refrigerant at the intermediate inlet. A second pressure sensor is arranged at an inlet of the compressor and is configured to obtain a second pressure of the refrigerant at the inlet of the compressor.

Images