A refrigeration system control method and device and power battery test equipment

Abstract

The application discloses a kind of refrigeration system control method, device and power battery test equipment.The refrigeration system control method includes: when the duration that refrigeration system maintains current test chamber actual temperature is greater than or equal to first preset duration, or the duration that electronic expansion valve maintains current opening degree is greater than or equal to second preset duration, target opening degree of electronic expansion valve is updated;When the first difference between the actual temperature of test chamber and evaporator outlet temperature is less than first temperature determination value, or the first difference is greater than second temperature determination value, the opening degree of electronic expansion valve is adjusted according to target opening degree;When the first difference is greater than or equal to first temperature determination value, and less than or equal to second temperature determination value, electronic expansion valve maintains current opening degree for second preset duration.The technical scheme of the embodiment of the application avoids the problem of liquid strike and oil shortage of compressor, and ensures that the refrigeration system can operate normally and reliably.

Description

[0001] This invention is a divisional application, with parent application number 2022115241768 and application date of December 1, 2022. Technical Field

[0002] This invention relates to the field of refrigeration technology, and in particular to a refrigeration system control method, device, and power battery testing equipment. Background Technology

[0003] Environmental testing equipment for power batteries is used to simulate the effects of temperature stress on batteries under different environmental conditions. It is commonly used to test battery quality, charge / discharge performance, lifespan, and long-term reliability. The equipment includes a refrigeration system for cooling the battery when it reaches high temperatures.

[0004] The main cooling circuit of the refrigeration system includes a condenser, a main valve, an evaporator, and a compressor. The compressor inlet side is the low-pressure, low-temperature side, and the compressor outlet side is the high-temperature, high-pressure side. The opening degree of the main valve of the main cooling circuit is controlled according to a fixed temperature range, that is, according to the temperature range corresponding to the temperature of the power battery and the environment in which the refrigeration system is located, the opening degree of the main valve is controlled.

[0005] The opening degree of the main valve of the refrigeration main circuit is controlled according to a fixed temperature range. This ensures that the main valve maintains its current opening degree even in the event of a power failure or alarm shutdown. Before the next refrigeration cycle starts, the refrigerant migrates to the low-pressure, low-temperature side, causing a large amount of refrigerant to accumulate on the low-pressure side. This can lead to problems such as liquid slugging and oil shortage in the compressor, making it impossible to test some operating points normally. In severe cases, it can damage the compressor, prevent the refrigeration system from operating, and consequently make battery testing impossible. Summary of the Invention

[0006] This invention provides a refrigeration system control method, device, and power battery testing equipment to solve the problems of liquid slugging and oil shortage in compressors of refrigeration systems.

[0007] According to one aspect of the present invention, a method for controlling a refrigeration system is provided, the refrigeration system comprising a refrigeration main circuit; the refrigeration main circuit comprising a compressor, a condenser, an electronic expansion valve, and an evaporator connected in series; the evaporator being located in a test chamber;

[0008] The control method includes:

[0009] When the duration for which the refrigeration system maintains the current actual temperature of the test chamber is greater than or equal to a first preset duration, or when the duration for which the electronic expansion valve maintains its current opening is greater than or equal to a second preset duration, the target opening of the electronic expansion valve is updated.

[0010] When the first difference between the actual temperature of the test chamber and the evaporator outlet temperature is less than the first temperature judgment value, or the first difference is greater than the second temperature judgment value, the opening of the electronic expansion valve is adjusted according to the target opening to make the difference between the actual temperature of the test chamber and the set temperature of the test chamber within the preset difference range.

[0011] When the first difference is greater than or equal to the first temperature determination value and less than or equal to the second temperature determination value, the electronic expansion valve maintains the current opening for a second preset duration.

[0012] The refrigeration system further includes a liquid injection line; the liquid injection line is connected between the inlet of the compressor and the inlet of the evaporator, and the liquid injection line includes a liquid injection valve and a first capillary tube connected in series;

[0013] The control method further includes:

[0014] Determine the first deviation range within which the second difference between the actual exhaust temperature value and the target exhaust temperature value of the compressor lies;

[0015] From the first preset relationship, find the target state of the spray valve corresponding to the first deviation range under the current operating condition; wherein, the current operating condition includes the actual temperature of the test chamber and the current ambient temperature of the environment where the refrigeration system is located, and the first preset relationship is the correspondence between the actual temperature, the current ambient temperature, the first deviation range and the target state;

[0016] The spray valve is opened or closed according to the target state;

[0017] And / or,

[0018] Determine the second deviation range in which the third difference between the actual intake temperature value and the target intake temperature value of the compressor falls;

[0019] From the second preset relationship, find the target state of the injection valve corresponding to the second deviation range under the current operating condition; wherein, the second preset relationship is the correspondence between the actual temperature, the current ambient temperature, the second deviation range and the target state;

[0020] The spray valve is opened or closed according to the target state.

[0021] Optionally, when the first difference between the actual temperature of the test chamber and the evaporator outlet temperature is less than a first temperature judgment value, or the first difference is greater than a second temperature judgment value, the opening of the electronic expansion valve is adjusted according to the target opening to ensure that the difference between the actual temperature of the test chamber and the set temperature of the test chamber is within a preset difference range, including:

[0022] When the first difference is less than the first temperature judgment value, the opening of the electronic expansion valve is reduced according to the opening adjustment rate until the opening of the electronic expansion valve reaches the target opening, so that the difference between the actual temperature of the test chamber and the set temperature of the test chamber is within the preset difference range.

[0023] When the first difference is greater than the second temperature determination value, the opening of the electronic expansion valve is increased according to the opening adjustment rate until the opening of the electronic expansion valve reaches the target opening, so that the difference between the actual temperature of the test chamber and the set temperature of the test chamber is within the preset difference range.

[0024] Optionally, before reducing the opening of the electronic expansion valve according to the opening adjustment rate when the first difference is less than the first temperature determination value, the method further includes:

[0025] The opening adjustment rate of the electronic expansion valve is calculated based on the target opening degree, the current opening degree of the electronic expansion valve, the start time of the electronic expansion valve opening adjustment, and the end time of the electronic expansion valve opening adjustment.

[0026] Optionally, the control method further includes:

[0027] Based on the actual exhaust temperature range of the compressor and the relationship between the actual exhaust temperature and time, the liquid injection valve is controlled to open or close.

[0028] And / or, based on the actual suction temperature range of the compressor and the relationship between the actual suction temperature and time, control the liquid injection valve to open or close.

[0029] Optionally, before controlling the opening or closing of the injection valve based on the actual exhaust temperature range of the compressor and the relationship between the actual exhaust temperature and time, the method further includes:

[0030] Obtain the first actual exhaust temperature value of the compressor at the first moment and the second actual exhaust temperature value of the compressor at the second moment;

[0031] Determine the exhaust temperature range in which the first actual exhaust temperature value or the second actual exhaust temperature value falls;

[0032] The relationship between the actual exhaust temperature value and time is determined based on the ratio of the first temperature difference between the second actual exhaust temperature value and the first actual exhaust temperature value to the first time period; wherein, the first time period is the time difference between the second time moment and the first time moment.

[0033] Before controlling the opening or closing of the injection valve based on the actual suction temperature range of the compressor and the relationship between the actual suction temperature and time, the method further includes:

[0034] Obtain the first actual suction temperature value of the compressor at the third time point and the second actual suction temperature value of the compressor at the fourth time point;

[0035] Determine the range of inhalation temperature where the first actual inhalation temperature or the second actual inhalation temperature value falls;

[0036] The relationship between the actual inhalation temperature value and time is determined based on the ratio of the second temperature difference between the second actual inhalation temperature value and the first actual inhalation temperature value to the second time period; wherein, the second time period is the time difference between the fourth time point and the third time point.

[0037] Optionally, controlling the liquid injection valve to open or close based on the actual exhaust temperature range of the compressor and the relationship between the actual exhaust temperature and time includes:

[0038] The temperature range between the minimum and maximum exhaust temperatures is divided into a first exhaust temperature range and a second exhaust temperature range; wherein, the first exhaust temperature range is from the minimum exhaust temperature to the median exhaust temperature, and the second exhaust temperature range is from the median exhaust temperature to the maximum exhaust temperature.

[0039] If the actual exhaust temperature value is within the first exhaust temperature range, and the actual exhaust temperature value decreases over time, then the injection valve is controlled to close.

[0040] If the actual exhaust temperature value is within the second exhaust temperature range, and the actual exhaust temperature value increases with time, then the injection valve is controlled to open.

[0041] Optionally, controlling the liquid injection valve to open or close based on the actual suction temperature range of the compressor and the relationship between the actual suction temperature and time includes:

[0042] The temperature values ​​between the minimum and maximum inhalation temperature are divided into a first inhalation temperature range and a second inhalation temperature range; wherein, the first inhalation temperature range is from the minimum inhalation temperature to the median inhalation temperature, and the second inhalation temperature range is from the median inhalation temperature to the maximum inhalation temperature.

[0043] If the actual inhalation temperature value is within the first inhalation temperature range, and the actual inhalation temperature value decreases over time, then the spray valve is controlled to close.

[0044] If the actual intake temperature value is within the second intake temperature range, and the actual intake temperature value increases with time, then the spray valve is controlled to open.

[0045] Optionally, the refrigeration system further includes a hot gas bypass supply line, which is connected between the outlet of the compressor and the inlet of the evaporator. The hot gas bypass supply line includes a hot gas valve and a second capillary tube.

[0046] The control method further includes:

[0047] When the actual temperature of the test chamber is lower than the preset temperature of the test chamber, the hot gas valve is controlled to open;

[0048] When the actual temperature is greater than or equal to the preset temperature, the hot gas valve is controlled to close.

[0049] According to another aspect of the present invention, a refrigeration system control device is provided, the refrigeration system including a refrigeration main circuit; the refrigeration main circuit includes a compressor, a condenser, an electronic expansion valve and an evaporator connected in series; the evaporator is located in a test chamber;

[0050] The refrigeration system control device includes:

[0051] The target opening update module is used to update the target opening of the electronic expansion valve when the duration for which the refrigeration system maintains the current actual temperature of the test chamber is greater than or equal to a first preset duration, or when the duration for which the electronic expansion valve maintains the current opening is greater than or equal to a second preset duration.

[0052] The opening adjustment module is used to adjust the opening of the electronic expansion valve according to the target opening when the first difference between the actual temperature of the test chamber and the evaporator outlet temperature is less than a first temperature judgment value, or the first difference is greater than a second temperature judgment value, so that the difference between the actual temperature of the test chamber and the set temperature of the test chamber is within a preset difference range.

[0053] An opening maintenance module is used to maintain the electronic expansion valve at its current opening for a second preset duration when the first difference is greater than or equal to the first temperature determination value and less than or equal to the second temperature determination value.

[0054] The refrigeration system control unit also includes a liquid injection valve control module, which is used for:

[0055] Determine the first deviation range within which the second difference between the actual exhaust temperature value and the target exhaust temperature value of the compressor lies;

[0056] From the first preset relationship, find the target state of the spray valve corresponding to the first deviation range under the current operating condition; wherein, the current operating condition includes the actual temperature of the test chamber and the current ambient temperature of the environment where the refrigeration system is located, and the first preset relationship is the correspondence between the actual temperature, the current ambient temperature, the first deviation range and the target state;

[0057] The spray valve is opened or closed according to the target state;

[0058] And / or,

[0059] Determine the second deviation range in which the third difference between the actual intake temperature value and the target intake temperature value of the compressor falls;

[0060] From the second preset relationship, find the target state of the injection valve corresponding to the second deviation range under the current operating condition; wherein, the second preset relationship is the correspondence between the actual temperature, the current ambient temperature, the second deviation range and the target state;

[0061] The spray valve is opened or closed according to the target state.

[0062] According to another aspect of the present invention, a power battery testing device is provided, the power battery testing device including a battery testing apparatus, a refrigeration system and a refrigeration system control device as described in any embodiment of the present invention;

[0063] The battery testing device is connected to the power battery, and the battery testing device is used to obtain parameter information of the power battery at different temperatures;

[0064] The refrigeration system control device is connected to the refrigeration system and is used to control the operation of the refrigeration system when the temperature of the power battery is greater than the temperature threshold.

[0065] The technical solution of this invention adjusts the opening of the electronic expansion valve according to a target opening degree when the first difference between the actual temperature of the test chamber and the evaporator outlet temperature is less than a first temperature judgment value, or the first difference is greater than a second temperature judgment value. This ensures that the opening of the electronic expansion valve reaches the target opening degree, thereby keeping the difference between the actual temperature of the test chamber and the set temperature of the test chamber within a preset range. Therefore, it achieves control of the electronic expansion valve opening according to actual needs, maintaining the electronic expansion valve opening at a suitable state, thus avoiding problems such as liquid slugging and oil shortage in the compressor. When the first difference between the actual temperature of the test chamber and the evaporator outlet temperature is greater than or equal to the first temperature judgment value and less than or equal to the second temperature judgment value, the electronic expansion valve maintains its current opening degree. If the duration of maintaining the current opening degree reaches a second preset duration, it is then determined whether adjustment of the electronic expansion valve is necessary. By periodically determining the first difference between the actual temperature of the test chamber and the evaporator outlet temperature, the opening of the electronic expansion valve can be adjusted in a timely manner when the first difference is less than or greater than a first temperature judgment value. This ensures that the opening of the electronic expansion valve is maintained at an appropriate state, thereby guaranteeing the normal operation of the compressor and preventing problems such as liquid slugging and oil shortage. The technical solution of this invention solves the problems of liquid slugging and oil shortage in compressors, ensuring the normal operation of the refrigeration system.

[0066] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0067] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0068] Figure 1 This is a schematic diagram of the structure of a refrigeration system in the prior art;

[0069] Figure 2 This is a flowchart of a refrigeration system control method provided in an embodiment of the present invention;

[0070] Figure 3 This is a schematic diagram of the structure of a refrigeration system provided in an embodiment of the present invention;

[0071] Figure 4 This is a flowchart of another refrigeration system control method provided in an embodiment of the present invention;

[0072] Figure 5 This is a flowchart of another refrigeration system control method provided in an embodiment of the present invention;

[0073] Figure 6 This is a flowchart of another refrigeration system control method provided in an embodiment of the present invention;

[0074] Figure 7 This is a flowchart of another refrigeration system control method provided in an embodiment of the present invention;

[0075] Figure 8 This is a flowchart of another refrigeration system control method provided in an embodiment of the present invention;

[0076] Figure 9 This is a schematic diagram of the structure of a refrigeration system control device provided in an embodiment of the present invention;

[0077] Figure 10 This is a schematic diagram of the structure of a battery testing device provided in an embodiment of the present invention. Detailed Implementation

[0078] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0079] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the term "comprising" and any variations thereof are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0080] Commonly used power battery cooling systems employ vapor compression refrigeration. Figure 1 This is a schematic diagram of the structure of a refrigeration system in the prior art, such as... Figure 1As shown, the refrigeration system includes a compressor 110, a condenser 120, a condenser fan N1, a dryer filter G1, an electronic expansion valve 130, an evaporator 140, a circulating fan F1, a heater 170, a liquid injection valve 210, a first capillary tube 220, a hot gas valve 310, and a second capillary tube 320. The evaporator 140 is located in the test chamber 150. The operation of the refrigeration system is as follows:

[0081] When the start button is pressed, the refrigeration system begins operation. Compressor 110, energized, draws in superheated vapor, compressing the gaseous refrigerant into high-temperature, high-pressure gaseous superheated vapor. This high-temperature, high-pressure gaseous superheated vapor enters condenser 120 through the exhaust pipe. Condenser 120 and condenser fan N1 condense the vapor into room-temperature, high-pressure liquid refrigerant. This room-temperature, high-pressure liquid refrigerant passes through dryer filter G1 to remove moisture, then splits into two streams. One stream passes through the main circuit's electronic expansion valve 130 for throttling and pressure reduction before entering evaporator 140 and circulating fan F1 for evaporation, vaporization, heat absorption, and cooling to lower the test chamber temperature. The remaining liquid stream passes through evaporator 140... A heater 170 is also provided. When the temperature of the test chamber approaches the target set temperature, the heater 170 is activated. The heater 170 performs heat and cold counterbalancing to maintain the temperature of the test chamber 150 within the target set temperature range. After evaporation, the refrigerant becomes superheated vapor and is drawn into the suction port of the compressor 110 through the suction pipe to complete the cooling cycle. Another path passes through the injection valve 210 to enter the first capillary tube 220. After being throttled and depressurized by the first capillary tube 220, it is injected into the suction pipe of the compressor 110 to prevent the superheated vapor drawn into the compressor 110 from being too hot, thus completing the injection cooling supplementary path. In addition, there is a hot gas bypass circuit. The high-temperature and high-pressure gaseous refrigerant superheated vapor discharged from the compressor 110 enters the second capillary tube 320 through the hot gas valve 310. After being throttled and depressurized by the second capillary tube 320, it enters the inlet of the evaporator 140. This prevents the temperature of the test chamber 150 from being too low, which would cause the pressure inside the evaporator 140 to be too low, thus causing poor oil return and damage to the compressor 110.

[0082] However, during the above adjustment process, the opening state of the electronic expansion valve 130 is controlled within a fixed temperature range. In this case, under power failure or alarm shutdown conditions, the electronic expansion valve 130 still maintains its current opening. Before the next refrigeration cycle starts, the refrigerant migrates to the low-pressure and low-temperature side, which will cause a large amount of refrigerant to accumulate on the low-pressure side. In mild cases, the compressor may experience liquid slugging or oil shortage; in severe cases, the compressor 110 may be damaged, the refrigeration system may not be able to operate, and the battery test may not be able to be carried out.

[0083] To address the aforementioned technical problems, embodiments of the present invention provide a refrigeration system control method. Figure 2 This is a flowchart of a refrigeration system control method provided in an embodiment of the present invention. Figure 3 This is a schematic diagram of the structure of a refrigeration system provided in an embodiment of the present invention, as shown below. Figure 3 As shown, the refrigeration system includes a main refrigeration circuit; the main refrigeration circuit includes a compressor 110, a condenser 120, an electronic expansion valve 130, and an evaporator 140 connected in series; the evaporator 140 is located in the test chamber 150; the refrigeration system also includes a test chamber temperature sensor T1 and an evaporator outlet temperature sensor T2, the test chamber temperature sensor T1 is located in the test chamber 150, and the evaporator outlet temperature sensor T2 is located at the outlet of the evaporator 140.

[0084] like Figure 2 and Figure 3 As shown, the refrigeration system control method includes:

[0085] S101. When the duration for which the refrigeration system maintains the current actual temperature of the test chamber is greater than or equal to the first preset duration, or when the duration for which the electronic expansion valve maintains the current opening is greater than or equal to the second preset duration, update the target opening of the electronic expansion valve.

[0086] Specifically, if the duration for which the refrigeration system maintains the current actual temperature of the test chamber is greater than or equal to a first preset duration, or if the duration for which the electronic expansion valve 130 maintains its current opening is greater than or equal to a second preset duration, it indicates that the electronic expansion valve 130 has been open for an extended period. The current oil return rate is insufficient to sustain the operation of the compressor 110, causing refrigerant to migrate to the low-pressure, low-temperature side. This results in a large accumulation of refrigerant on the low-pressure side, leading to oil shortage or liquid slugging in the compressor 110. Therefore, the target opening of the electronic expansion valve 130 is redefined. The target opening of the electronic expansion valve 130 refers to the maximum opening required when the actual temperature of the test chamber meets the preset temperature condition. The preset temperature condition is that the difference between the actual temperature of the test chamber and the set temperature of the test chamber is within a preset range.

[0087] S102. Determine that the first difference between the actual temperature of the test chamber and the evaporator outlet temperature is greater than or equal to the first temperature judgment value and less than or equal to the second temperature judgment value; if not, proceed to step S103; if yes, proceed to step S104.

[0088] Specifically, the second temperature judgment value is greater than the first temperature judgment value. When the first difference between the actual temperature of the test chamber 150 and the evaporator outlet temperature is greater than or equal to the first temperature judgment value and less than or equal to the second temperature judgment value, it indicates that the actual temperature of the test chamber 150 is within the normal range, and there is no need to adjust the opening of the electronic expansion valve 130. When the first difference between the actual temperature of the test chamber and the evaporator outlet temperature is less than the first temperature judgment value, or the first difference is greater than the second temperature judgment value, it indicates that the actual temperature of the test chamber 150 is abnormal, and it is necessary to adjust the opening of the electronic expansion valve 130.

[0089] S103. Adjust the opening of the electronic expansion valve according to the target opening degree so that the difference between the actual temperature of the test chamber and the set temperature of the test chamber is within the preset difference range.

[0090] Specifically, when the first difference between the actual temperature of the test chamber 150 and the evaporator outlet temperature is less than the first temperature judgment value, it indicates that the actual temperature of the test chamber 150 is too low, that is, too much refrigerant is entering the test chamber 150. In this case, it is necessary to adjust the opening of the electronic expansion valve 130, for example, by reducing the opening of the electronic expansion valve 130. The opening of the electronic expansion valve 130 is adjusted according to the target opening so that the opening of the electronic expansion valve 130 reaches the target opening, thereby ensuring that the difference between the actual temperature of the test chamber 150 and the set temperature of the test chamber is within the preset difference range. When the first difference between the actual temperature of test chamber 150 and the evaporator outlet temperature exceeds the second temperature judgment value, it indicates that the actual temperature of test chamber 150 is too high, meaning that too little refrigerant is entering test chamber 150. In this case, it is necessary to adjust the opening of electronic expansion valve 130, for example, by increasing the opening of electronic expansion valve 130. Adjusting the opening of electronic expansion valve 130 according to the target opening ensures that the opening of electronic expansion valve 130 reaches the target opening, thereby keeping the difference between the actual temperature of test chamber 150 and the set temperature within the preset difference range. Therefore, it achieves the goal of controlling the opening of electronic expansion valve 130 according to actual needs, maintaining the opening of electronic expansion valve 130 at an appropriate state, and thus avoiding liquid slugging and oil shortage problems in compressor 110.

[0091] S104, The electronic expansion valve maintains the current opening for a second preset duration.

[0092] Specifically, when the first difference between the actual temperature of the test chamber 150 and the evaporator outlet temperature is greater than or equal to the first temperature judgment value and less than or equal to the second temperature judgment value, it indicates that the actual temperature of the test chamber 150 is within the normal range, and the difference between the actual temperature of the test chamber 150 and the set temperature of the test chamber is within the preset difference range. Therefore, no adjustment is needed for the electronic expansion valve 130; that is, the electronic expansion valve 130 maintains its current opening, and the process returns to step S101. When the duration for which the electronic expansion valve 130 maintains its current opening reaches the second preset duration, the first difference is judged again to determine whether adjustment of the electronic expansion valve 130 is necessary. By periodically judging the first difference between the actual temperature of the test chamber 150 and the evaporator outlet temperature, the opening of the electronic expansion valve 130 can be adjusted in a timely manner when the first difference is less than or greater than the first temperature judgment value, ensuring that the opening of the electronic expansion valve 130 is maintained in a suitable state. This guarantees that the compressor 110 can operate normally, thereby avoiding problems such as liquid slugging and oil shortage in the compressor 110.

[0093] The technical solution of this embodiment adjusts the opening of the electronic expansion valve according to a target opening degree when the first difference between the actual temperature of the test chamber and the evaporator outlet temperature is less than a first temperature judgment value, or the first difference is greater than a second temperature judgment value. This ensures that the opening of the electronic expansion valve reaches the target opening degree, thereby keeping the difference between the actual temperature of the test chamber and the set temperature of the test chamber within a preset range. Therefore, it achieves control of the electronic expansion valve opening degree according to actual needs, maintaining the electronic expansion valve opening degree in a suitable state, thus avoiding problems such as liquid slugging and oil shortage in the compressor. When the first difference between the actual temperature of the test chamber and the evaporator outlet temperature is greater than or equal to the first temperature judgment value and less than or equal to the second temperature judgment value, the electronic expansion valve maintains its current opening degree. If the duration of maintaining the current opening degree reaches a second preset duration, it is then determined whether adjustment of the electronic expansion valve is necessary. By periodically determining the first difference between the actual temperature of the test chamber and the evaporator outlet temperature, the opening of the electronic expansion valve can be adjusted in a timely manner when the first difference is less than or greater than a first temperature judgment value. This ensures that the opening of the electronic expansion valve is maintained at an appropriate state, thereby guaranteeing the normal operation of the compressor and preventing problems such as liquid slugging and oil shortage. The technical solution of this invention solves the problems of liquid slugging and oil shortage in compressors, ensuring the normal operation of the refrigeration system.

[0094] Based on the above technical solutions, Figure 4 This is a flowchart of another refrigeration system control method provided by an embodiment of the present invention. This embodiment is a further refinement of S102 in the above embodiment. Figure 3 and Figure 4 As shown, the refrigeration system control method includes:

[0095] S201. When the duration for which the refrigeration system maintains the current actual temperature of the test chamber is greater than or equal to the first preset duration, or when the duration for which the electronic expansion valve maintains the current opening is greater than or equal to the second preset duration, update the target opening of the electronic expansion valve.

[0096] S202. Calculate the opening adjustment rate of the electronic expansion valve based on the target opening degree, the current opening degree of the electronic expansion valve, the start time of the electronic expansion valve opening adjustment, and the end time of the electronic expansion valve opening adjustment.

[0097] Specifically, the target opening degree of the electronic expansion valve 130 is D1, the current opening degree of the electronic expansion valve 130 is D2, the start time of the opening degree adjustment of the electronic expansion valve 130 is t1, and the end time of the opening degree adjustment of the electronic expansion valve 130 is t2. Therefore, the opening degree adjustment rate of the electronic expansion valve 130 is... The end time t2 for adjusting the opening of the electronic expansion valve 130 is defined as t1 + max{Δt2a, Δt2b}. Here, Δt2a is the time required for the electronic expansion valve 130 to reach its maximum opening when the difference between the actual and set temperatures in the test chamber is within a preset range; Δt2b is the time required for the electronic expansion valve 130 to reach its maximum opening when the difference between the actual and set temperatures in the test chamber is within a preset range. Δt2a and Δt2b are determined by parameters observed during operation or based on experience.

[0098] S203. Determine whether the first difference between the actual temperature of the test chamber and the evaporator outlet temperature is less than the first temperature judgment value. If yes, proceed to step S204; otherwise, proceed to step S205.

[0099] Specifically, if the first difference between the actual temperature of the test chamber 150 and the evaporator outlet temperature is less than the first temperature judgment value, it indicates that the actual temperature of the test chamber 150 is too low and too much refrigerant is being input, requiring a reduction in the opening of the electronic expansion valve 130. If the first difference between the actual temperature of the test chamber 150 and the evaporator outlet temperature is greater than or equal to the first temperature judgment value, further judgment is needed to determine whether the first difference is greater than the second temperature judgment value.

[0100] S204. Reduce the opening of the electronic expansion valve according to the opening adjustment rate until the opening of the electronic expansion valve reaches the target opening, so that the difference between the actual temperature of the test chamber and the set temperature of the test chamber is within the preset difference range.

[0101] Specifically, the opening of the electronic expansion valve 130 is gradually reduced according to the opening adjustment rate to avoid large changes in opening, which could cause significant fluctuations in the inlet temperature of the evaporator 140 and result in a large impact on the evaporator 140, thus protecting both the evaporator 140 and the compressor 110. The opening of the electronic expansion valve 130 is gradually reduced until it reaches the target opening, ensuring that the difference between the actual temperature of the test chamber 150 and the set temperature of the test chamber is within a preset range. Therefore, the opening of the electronic expansion valve 130 is controlled according to actual needs, maintaining it at an appropriate level and preventing liquid slugging and oil shortage problems in the compressor 110.

[0102] S205. Determine whether the first difference between the actual temperature of the test chamber and the evaporator outlet temperature is greater than the second temperature judgment value. If yes, proceed to step S206; otherwise, proceed to step S207.

[0103] Specifically, when the first difference between the actual temperature of test chamber 150 and the evaporator outlet temperature is greater than the second temperature judgment value, it indicates that the actual temperature of test chamber 150 is too high and the refrigerant input is too low, requiring an increase in the opening of the electronic expansion valve. When the first difference between the actual temperature of test chamber 150 and the evaporator outlet temperature is greater than or equal to the first temperature judgment value and less than or equal to the second temperature judgment value, it indicates that the actual temperature of test chamber 150 is within the normal range, and the difference between the actual temperature of test chamber 150 and the set temperature of test chamber is within the preset difference range, requiring no adjustment of the electronic expansion valve 130.

[0104] S206. Increase the opening of the electronic expansion valve according to the opening adjustment rate until the opening of the electronic expansion valve reaches the target opening, so that the difference between the actual temperature of the test chamber and the set temperature of the test chamber is within the preset difference range.

[0105] Specifically, the opening of the electronic expansion valve 130 is gradually increased according to the opening adjustment rate to avoid large changes in opening that could impact the evaporator 140, thus protecting both the evaporator 140 and the compressor 110. The opening of the electronic expansion valve 130 is gradually increased until it reaches the target opening, ensuring that the difference between the actual temperature of the test chamber 150 and the set temperature is within a preset range. Therefore, the opening of the electronic expansion valve 130 is controlled according to actual needs, maintaining it at a suitable level to prevent liquid slugging and oil shortage problems in the compressor 110.

[0106] S207, The electronic expansion valve maintains the current opening for a second preset duration.

[0107] Based on the above technical solutions, such as Figure 3 As shown, the refrigeration system also includes a liquid injection line; the liquid injection line is connected between the inlet of the compressor 110 and the inlet of the evaporator 140, and includes a liquid injection valve 210 and a first capillary tube 220 connected in series; to prevent liquid slugging in the compressor 110, the liquid injection valve 210 of the liquid injection line also needs to be controlled to prevent excessive liquid injection from the liquid injection valve 210, which would cause liquid slugging in the compressor 110. The refrigeration system also includes an exhaust temperature sensor T3 and a suction temperature sensor T4. The exhaust temperature sensor T3 is located at the outlet of the compressor 110 and detects the exhaust temperature of the compressor 110. The suction temperature sensor T4 is located at the inlet of the compressor and detects the suction temperature of the compressor 110.

[0108] When controlling the opening and closing of the liquid injection valve 210, control can be based on the actual discharge temperature range and trend of the compressor 110, the actual suction temperature range and trend of the compressor 110, the first deviation range of the second difference between the actual discharge temperature and the target discharge temperature, or the second deviation range of the third difference between the actual suction temperature and the target suction temperature. The following description, in conjunction with the control methods for the liquid injection valve 210 and the electronic expansion valve 130, illustrates the refrigeration system control method, but is not intended to limit the scope of the invention.

[0109] In one implementation, Figure 5 This is a flowchart of another refrigeration system control method provided in an embodiment of the present invention. Optionally, refer to... Figure 3 and Figure 5 The refrigeration system control methods include:

[0110] S301. When the duration for which the refrigeration system maintains the current actual temperature of the test chamber is greater than or equal to the first preset duration, or when the duration for which the electronic expansion valve maintains the current opening is greater than or equal to the second preset duration, update the target opening of the electronic expansion valve.

[0111] S302. Determine that the first difference between the actual temperature of the test chamber and the evaporator outlet temperature is greater than or equal to the first temperature judgment value and less than or equal to the second temperature judgment value; if not, proceed to step S303; if yes, proceed to step S304.

[0112] S303. Adjust the opening of the electronic expansion valve according to the target opening degree so that the difference between the actual temperature of the test chamber and the set temperature of the test chamber is within the preset difference range.

[0113] S304, The electronic expansion valve maintains the current opening for a second preset duration.

[0114] S305. Obtain the first actual discharge temperature value of the compressor at the first moment and the second actual discharge temperature value of the compressor at the second moment.

[0115] Specifically, the first actual discharge temperature value of compressor 110 at the first moment is the first actual discharge temperature value of compressor 110 at the current moment. Then, after the refrigeration system has been running for a period of time, the second actual discharge temperature value of compressor 110 at the second moment is obtained. By obtaining the first actual discharge temperature value of compressor 110 at the first moment and the second actual discharge temperature value of compressor 110 at the second moment, it is convenient to determine the relationship between the discharge temperature of compressor 110 and time, that is, to determine the discharge temperature change trend of compressor 110.

[0116] S306. Determine the exhaust temperature range in which the first actual exhaust temperature value or the second actual exhaust temperature value is located.

[0117] Specifically, the exhaust temperature range is a plurality of ranges between the minimum and maximum exhaust temperature values. The maximum exhaust temperature TP_pv-max and the minimum exhaust temperature TP_pv-min are determined by testing, and at least one intermediate exhaust temperature value TP_pv-m1 is set; wherein TP_pv-min≤TP_pv-m1≤TP_pv-max; then the exhaust temperature range is divided into at least two ranges. The exhaust temperature range in which the first actual exhaust temperature value or the second actual exhaust temperature value is located is determined by comparing the second actual exhaust temperature value or the first actual exhaust temperature value with the boundary value of the exhaust temperature range.

[0118] S307. Determine the relationship between the actual exhaust temperature value and time based on the ratio of the first temperature difference between the second actual exhaust temperature value and the first actual exhaust temperature value to the first time period; wherein, the first time period is the time difference between the second moment and the first moment.

[0119] Specifically, based on the ratio of the first temperature difference between the second actual exhaust temperature value and the first actual exhaust temperature value to the first time period, the rate of change of the actual exhaust temperature value can be determined, thereby determining the relationship between the actual exhaust temperature value and time, that is, determining the trend of change of the actual exhaust temperature value.

[0120] S308. Based on the actual exhaust temperature range of the compressor and the relationship between the actual exhaust temperature and time, control the liquid injection valve to open or close.

[0121] Specifically, if the actual discharge temperature of compressor 110 falls within a large boundary value of the discharge temperature range, close to the maximum discharge temperature, and the actual discharge temperature increases over time, indicating a large actual discharge temperature and an upward trend, then the liquid injection valve 210 is opened to inject liquid for cooling. Conversely, if the actual discharge temperature of compressor 110 falls within a small boundary value of the discharge temperature range, close to the minimum discharge temperature, and the actual discharge temperature decreases over time, indicating a small actual discharge temperature and a downward trend, then the liquid injection valve 210 is closed to prevent excessive liquid injection and liquid slugging in compressor 110. By controlling the opening and closing of the liquid injection valve 210 based on the discharge temperature range and the relationship between the actual discharge temperature and time, the liquid injection valve 210 is opened only as needed, preventing excessive liquid injection and liquid slugging in compressor 110, thus improving the reliability of the refrigeration system.

[0122] It should be noted that the control steps for opening or closing the injection valve 210 can be executed after the opening adjustment of the electronic expansion valve 130 is completed, or they can be executed simultaneously with the control steps for adjusting the opening of the electronic expansion valve 130. Figure 5 The flowchart illustrates that the control steps for opening or closing the injection valve 210 follow the opening adjustment of the electronic expansion valve 130, but does not limit the execution order.

[0123] Based on the above technical solution, optionally, S308, according to the actual exhaust temperature range of the compressor and the relationship between the actual exhaust temperature and time, controls the opening or closing of the injection valve, including:

[0124] Step a1: Divide the temperature values ​​between the minimum and maximum exhaust temperatures into a first exhaust temperature range and a second exhaust temperature range; wherein, the first exhaust temperature range is from the minimum exhaust temperature to the midpoint of the exhaust temperature, and the second exhaust temperature range is from the midpoint of the exhaust temperature to the maximum exhaust temperature.

[0125] Specifically, by setting an intermediate exhaust temperature value, a first exhaust temperature range [TP_pv-min, TP_pv-m1] and a second exhaust temperature range [TP_pv-m1, TP_pv-max] are obtained. By comparing the first or second actual exhaust temperature value with TP_pv-min, TP_pv-m1, and TP_pv-max, the exhaust temperature range in which the second actual exhaust temperature value falls is determined.

[0126] Step a2: If the actual exhaust temperature is within the first exhaust temperature range, and the actual exhaust temperature decreases over time, then the injection valve is closed.

[0127] Specifically, if the actual discharge temperature of the compressor 110 is within the first discharge temperature range, and the actual discharge temperature decreases over time, it indicates that the actual discharge temperature of the compressor 110 is small and the actual discharge temperature is trending downward. In this case, the liquid injection valve 210 is closed to prevent excessive liquid injection that could cause liquid slugging in the compressor 110.

[0128] Step a3: If the actual exhaust temperature is within the second exhaust temperature range, and the actual exhaust temperature increases over time, then control the injection valve to open.

[0129] Specifically, if the actual exhaust temperature of the compressor 110 is within the second exhaust temperature range, and the actual exhaust temperature increases with time, it indicates that the actual exhaust temperature of the compressor 110 is large and the actual exhaust temperature is on an upward trend. In this case, the liquid injection valve 210 is opened to inject liquid for cooling.

[0130] In another implementation, Figure 6 This is a flowchart of another refrigeration system control method provided in an embodiment of the present invention. Optionally, refer to... Figure 3 and Figure 6 The refrigeration system control methods include:

[0131] S401. When the duration for which the refrigeration system maintains the current actual temperature of the test chamber is greater than or equal to the first preset duration, or when the duration for which the electronic expansion valve maintains the current opening is greater than or equal to the second preset duration, update the target opening of the electronic expansion valve.

[0132] S402. Determine that the first difference between the actual temperature of the test chamber and the evaporator outlet temperature is greater than or equal to the first temperature judgment value and less than or equal to the second temperature judgment value; if not, proceed to step S403; if yes, proceed to step S404.

[0133] S403. Adjust the opening of the electronic expansion valve according to the target opening degree so that the difference between the actual temperature of the test chamber and the set temperature of the test chamber is within the preset difference range.

[0134] S404, The electronic expansion valve maintains the current opening for a second preset duration.

[0135] S405, Obtain the first actual suction temperature value of the compressor at the third time point and the second actual suction temperature value of the compressor at the fourth time point.

[0136] Specifically, the first actual suction temperature value of compressor 110 at the third moment is the first actual suction temperature value of compressor 110 at the current moment. Then, after the refrigeration system has been running for a period of time, the second actual suction temperature value of compressor 110 at the fourth moment is obtained. By obtaining the first actual suction temperature value of compressor 110 at the third moment and the second actual suction temperature value of compressor 110 at the fourth moment, it is convenient to determine the relationship between the suction temperature of compressor 110 and time, that is, to determine the suction temperature change trend of compressor 110.

[0137] S406. Determine the range of inhalation temperatures in which the first actual inhalation temperature or the second actual inhalation temperature value is located.

[0138] Specifically, the inhalation temperature range is a plurality of ranges between the minimum and maximum inhalation temperature. The maximum inhalation temperature TX_pv-max and the minimum inhalation temperature TX_pv-min are determined by testing, and at least one intermediate inhalation temperature value TX_pv-m1 is set; wherein TX_pv-min≤TX_pv-m1≤TX_pv-max; then the inhalation temperature range is divided into at least two ranges. The inhalation temperature range in which the first actual inhalation temperature value or the second actual inhalation temperature value is located is determined by comparing the second actual inhalation temperature value or the first actual inhalation temperature value with the boundary value of the inhalation temperature range.

[0139] S407. Determine the relationship between the actual inhalation temperature value and time based on the ratio of the second temperature difference between the second actual inhalation temperature value and the first actual inhalation temperature value to the second time period; wherein, the second time period is the time difference between the fourth time point and the third time point.

[0140] Specifically, based on the ratio of the second temperature difference between the second actual inhalation temperature value and the first actual inhalation temperature value to the second time period, the rate of change of the actual inhalation temperature value can be determined, thereby determining the relationship between the actual inhalation temperature value and time, that is, determining the trend of change of the actual inhalation temperature value.

[0141] S408. Based on the actual suction temperature range of the compressor and the relationship between the actual suction temperature and time, control the liquid injection valve to open or close.

[0142] Specifically, if the actual suction temperature of compressor 110 falls within a large boundary value of the suction temperature range, close to the maximum suction temperature, and the actual suction temperature increases over time, indicating a large actual suction temperature and an upward trend, then the liquid injection valve 210 is opened to inject liquid for cooling. Conversely, if the actual suction temperature of compressor 110 falls within a small boundary value of the suction temperature range, close to the minimum suction temperature, and the actual suction temperature decreases over time, indicating a small actual suction temperature and a downward trend, then the liquid injection valve 210 is closed to prevent excessive liquid injection and liquid slugging in compressor 110. By controlling the opening and closing of the liquid injection valve 210 based on the suction temperature range of compressor 110 and the relationship between the actual suction temperature and time, the liquid injection valve 210 is opened as needed, preventing excessive liquid injection and liquid slugging in compressor 110, thus improving the reliability of the refrigeration system.

[0143] It should be noted that the control steps for opening or closing the injection valve 210 can be executed after the opening adjustment of the electronic expansion valve 130 is completed, or they can be executed simultaneously with the control steps for adjusting the opening of the electronic expansion valve 130. Figure 6 The flowchart illustrates that the control steps for opening or closing the injection valve 210 follow the opening adjustment of the electronic expansion valve 130, but does not limit the execution order.

[0144] Optionally, S408 controls the liquid injection valve to open or close based on the actual suction temperature range of the compressor and the relationship between the actual suction temperature and time, including:

[0145] Step b1: Divide the temperature values ​​between the minimum and maximum inhalation temperatures into a first inhalation temperature range and a second inhalation temperature range; wherein, the first inhalation temperature range is from the minimum inhalation temperature to the median inhalation temperature, and the second inhalation temperature range is from the median inhalation temperature to the maximum inhalation temperature.

[0146] Specifically, by setting an intermediate inhalation temperature value TX_pv-m1, a first inhalation temperature range [TX_pv-min, TX_pv-m1] and a second inhalation temperature range [TX_pv-m1, TX_pv-max] are obtained. By comparing the first or second actual inhalation temperature value with TX_pv-min, TX_pv-m1, and TX_pv-max, the inhalation temperature range in which the second actual inhalation temperature value falls is determined.

[0147] Step b2: If the actual intake temperature value is within the first intake temperature range, and the actual intake temperature value decreases over time, then control the liquid injection valve to close.

[0148] Specifically, if the actual suction temperature of the compressor 110 is within the first suction temperature range, and the actual suction temperature decreases over time, indicating that the actual suction temperature of the compressor 110 is small and the actual suction temperature is trending downward, then the liquid injection valve 210 is closed to prevent excessive liquid injection from causing liquid slugging in the compressor 110.

[0149] Step b3: If the actual intake temperature is within the second intake temperature range, and the actual intake temperature increases over time, then control the liquid injection valve to open.

[0150] Specifically, if the actual suction temperature of the compressor 110 is within the second suction temperature range, and the actual suction temperature increases with time, it indicates that the actual suction temperature of the compressor 110 is large and the actual suction temperature is on an upward trend. Then, the liquid injection valve 210 is opened to inject liquid for cooling.

[0151] In another implementation, Figure 7 This is a flowchart of another refrigeration system control method provided in an embodiment of the present invention. Optionally, refer to... Figure 3 and Figure 7 The refrigeration system control methods include:

[0152] S501. When the duration for which the refrigeration system maintains the current actual temperature of the test chamber is greater than or equal to the first preset duration, or when the duration for which the electronic expansion valve maintains the current opening is greater than or equal to the second preset duration, update the target opening of the electronic expansion valve.

[0153] S502. Determine that the first difference between the actual temperature of the test chamber and the evaporator outlet temperature is greater than or equal to the first temperature judgment value and less than or equal to the second temperature judgment value; if not, proceed to step S503; if yes, proceed to step S504.

[0154] S503. Adjust the opening of the electronic expansion valve according to the target opening degree so that the difference between the actual temperature of the test chamber and the set temperature of the test chamber is within the preset difference range.

[0155] S504, The electronic expansion valve maintains the current opening for a second preset duration.

[0156] S505. Based on the first deviation range of the second difference between the actual discharge temperature value of the compressor and the target discharge temperature value under the current operating conditions, control the liquid injection valve to open or close; wherein, the current operating conditions include the actual temperature of the test chamber and the current ambient temperature of the environment in which the refrigeration system is located.

[0157] Specifically, under different operating conditions, when the second difference falls within the same first deviation range, the target state of the injection valve may be the same or different. Therefore, it is necessary to control the opening or closing of the injection valve according to the current operating conditions and the first deviation range of the second difference. For example, when the current ambient temperature is 10℃, the actual temperature of the test chamber is 100℃, and the first deviation range of the second difference is [5,15], the actual temperature of the test chamber is too high, the second difference is large, and the injection valve 210 is controlled to open. When the current ambient temperature is 10℃, the actual temperature of the test chamber is 20℃, and the first deviation range of the second difference is [5,15], the actual temperature of the test chamber is low, the second difference is large, and the injection valve 210 is controlled to close. Therefore, by controlling the opening or closing of the injection valve 210 more accurately according to the current operating conditions and the first deviation range of the second difference, liquid slugging of the compressor 110 can be further avoided, and the accuracy and reliability of the refrigeration system can be further improved.

[0158] It should be noted that the control steps for opening or closing the injection valve 210 can be executed after the opening adjustment of the electronic expansion valve 130 is completed, or they can be executed simultaneously with the control steps for adjusting the opening of the electronic expansion valve 130. Figure 7 The flowchart illustrates that the control steps for opening or closing the injection valve 210 follow the opening adjustment of the electronic expansion valve 130, but does not limit the execution order.

[0159] Optionally, S505 controls the liquid injection valve to open or close based on the first deviation range of the second difference between the actual discharge temperature value and the target discharge temperature value of the compressor under the current operating conditions, including:

[0160] Step c1: Determine the first deviation range of the second difference between the actual exhaust temperature value of the compressor and the target exhaust temperature value.

[0161] Specifically, the first deviation range is, for example, [0,5], [5,15] and [15,25]. The second difference is compared with the boundary value of the first deviation range to determine the first deviation range in which the second difference is located, so as to control the opening or closing of the spray valve 210 according to the first deviation range in which the second difference is located.

[0162] Step c2: From the first preset relationship, find the target state of the injection valve corresponding to the first deviation range under the current working condition; wherein, the first preset relationship is the correspondence between the actual temperature, the current ambient temperature, the first deviation range and the target state.

[0163] Specifically, for example, the correspondence between the actual temperature of the test chamber, the current ambient temperature, the first deviation range, and the target state of the spray valve can be predetermined and stored as a first preset relationship through experimentation. This relationship can be stored in the form of a table or curve. When determining the current operating condition and the first deviation range of the second difference, the target state of the spray valve 210 can be directly found from the first preset relationship. The target state includes whether the spray valve 210 is open or closed. Table 1 is a schematic table of the first preset relationship. As shown in Table 1, based on the determined actual temperature of the test chamber, the actual temperature, the current ambient temperature, and the first deviation range of the second difference can be determined, and the target state of the spray valve can be found.

[0164] Table 1. Schematic diagram of the first preset relationship

[0165]

[0166] Step c3: Control the spray valve to open or close according to the target status.

[0167] Specifically, the liquid injection valve 210 is opened or closed according to the target state found in the first preset relationship, so as to achieve accurate control of the liquid injection valve 210, further avoid liquid slugging in the compressor 110, and further improve the accuracy and reliability of the refrigeration system.

[0168] In another implementation, Figure 8 This is a flowchart of another refrigeration system control method provided in an embodiment of the present invention. Optionally, refer to... Figure 3 and Figure 8 The refrigeration system control methods include:

[0169] S601. When the duration for which the refrigeration system maintains the current actual temperature of the test chamber is greater than or equal to the first preset duration, or when the duration for which the electronic expansion valve maintains the current opening is greater than or equal to the second preset duration, update the target opening of the electronic expansion valve.

[0170] S602. Determine that the first difference between the actual temperature of the test chamber and the evaporator outlet temperature is greater than or equal to the first temperature judgment value and less than or equal to the second temperature judgment value; if not, proceed to step S603; if yes, proceed to step S604.

[0171] S603. Adjust the opening of the electronic expansion valve according to the target opening degree so that the difference between the actual temperature of the test chamber and the set temperature of the test chamber is within the preset difference range.

[0172] S604, The electronic expansion valve maintains the current opening for a second preset duration.

[0173] S605. Based on the second deviation range of the third difference between the actual suction temperature value of the compressor and the target suction temperature value under the current operating conditions, control the liquid injection valve to open or close; wherein, the current operating conditions include the actual temperature of the test chamber and the current ambient temperature of the environment in which the refrigeration system is located.

[0174] Specifically, under different operating conditions, when the second deviation range of the third difference is the same, the target state of the injection valve may be the same or different. Therefore, it is necessary to control the opening or closing of the injection valve according to the current operating conditions and the second deviation range of the third difference.

[0175] It should be noted that the control steps for opening or closing the injection valve 210 can be executed after the opening adjustment of the electronic expansion valve 130 is completed, or they can be executed simultaneously with the control steps for adjusting the opening of the electronic expansion valve 130. Figure 8 The flowchart illustrates that the control steps for opening or closing the injection valve 210 follow the opening adjustment of the electronic expansion valve 130, but does not limit the execution order.

[0176] Optionally, S605 controls the liquid injection valve to open or close based on the second deviation range of the third difference between the actual suction temperature value and the target suction temperature value of the compressor under the current operating conditions, including:

[0177] Step d1: Determine the second deviation range of the third difference between the actual suction temperature value of the compressor and the target suction temperature value.

[0178] Specifically, the second deviation range is, for example, [0,5], [5,15] and [15,25]. The third difference is compared with the boundary value of the second deviation range to determine the second deviation range in which the third difference is located, so as to control the opening or closing of the spray valve 210 according to the second deviation range in which the third difference is located.

[0179] Step d2: From the second preset relationship, find the target state of the injection valve corresponding to the second deviation range under the current working condition; wherein, the second preset relationship is the correspondence between the actual temperature, the current ambient temperature, the second deviation range and the target state.

[0180] Specifically, for example, the correspondence between the actual temperature of the test chamber, the current ambient temperature, the second deviation range, and the target state of the spray valve can be predetermined and stored as a second preset relationship through experimentation. This relationship can be stored in the form of a table or curve. When determining the second deviation range of the current operating condition and the third difference, the target state of the corresponding spray valve 210 can be directly found from the second preset relationship. The target state includes whether the spray valve 210 is open or closed.

[0181] Step d3: Control the spray valve to open or close according to the target status.

[0182] Specifically, the liquid injection valve 210 is opened or closed according to the target state found in the first preset relationship, so as to achieve accurate control of the liquid injection valve 210, further avoid liquid slugging in the compressor 110, and further improve the accuracy and reliability of the refrigeration system.

[0183] Based on the above technical solutions, optionally, refer to Figure 3 The refrigeration system also includes a hot gas bypass supply line, which is connected between the outlet of the compressor 110 and the inlet of the evaporator 140. The hot gas bypass supply line includes a hot gas valve 310 and a second capillary tube 320.

[0184] Optionally, the refrigeration system control method further includes:

[0185] When the actual temperature in the test chamber is lower than the preset temperature of the test chamber, the hot gas valve is opened.

[0186] Specifically, when the actual temperature of the test chamber 150 is lower than the preset temperature of the test chamber 150, it indicates that the actual temperature inside the test chamber 150 is too low. It is necessary to control the hot gas valve 310 to open. The hot gas valve 310 enters the evaporator 140 through the second capillary tube 320, thereby increasing the actual temperature of the test chamber 150. This prevents the evaporator 140 pressure from being too low, which would cause poor oil return to the compressor 110, and further prevents the compressor 110 from experiencing oil shortage problems.

[0187] When the actual temperature is greater than or equal to the preset temperature, the hot air valve is closed.

[0188] Specifically, when the actual temperature of the test chamber 150 is greater than or equal to the preset temperature, it indicates that the actual temperature inside the test chamber 150 is high and there is no need to add hot air, so the hot air valve 310 is closed.

[0189] It should be noted that in some other embodiments, the hot gas valve 310 can also be controlled according to the control method of the electronic expansion valve 130 in any of the above embodiments.

[0190] Figure 9 This is a schematic diagram of the structure of a refrigeration system control device provided in an embodiment of the present invention, as shown below. Figure 9 As shown, the device includes: a target opening update module 701, an opening adjustment module 702, and an opening maintenance module 703. The target opening update module 701 is used to update the target opening of the electronic expansion valve when the duration for which the refrigeration system maintains the current actual temperature of the test chamber is greater than or equal to a first preset duration, or when the duration for which the electronic expansion valve maintains the current opening is greater than or equal to a second preset duration. The opening adjustment module 702 is used to adjust the opening of the electronic expansion valve according to the target opening when the first difference between the actual temperature of the test chamber and the evaporator outlet temperature is less than a first temperature judgment value, or when the first difference is greater than a second temperature judgment value, so that the difference between the actual temperature of the test chamber and the set temperature of the test chamber is within a preset difference range. The opening maintenance module 703 is used to maintain the current opening of the electronic expansion valve for a second preset duration when the first difference is greater than or equal to the first temperature judgment value and less than or equal to the second temperature judgment value.

[0191] Optionally, the refrigeration system control device further includes a liquid injection valve control module, which controls the liquid injection valve to open or close based on the actual discharge temperature range of the compressor and the relationship between the actual discharge temperature and time; and / or controls the liquid injection valve to open or close based on the actual suction temperature range of the compressor and the relationship between the actual suction temperature and time.

[0192] Optionally, the injection valve control module is further configured to control the injection valve to open or close based on a first deviation range of a second difference between the actual discharge temperature value of the compressor and the target discharge temperature value under the current operating conditions; wherein the current operating conditions include the actual temperature of the test chamber and the current ambient temperature of the environment in which the refrigeration system is located; and / or, to control the injection valve to open or close based on a second deviation range of a third difference between the actual suction temperature value and the target suction temperature value under the current operating conditions.

[0193] Optionally, the refrigeration system control device also includes a hot gas valve control module, which controls the hot gas valve to open when the actual temperature of the test chamber is less than the preset temperature of the test chamber, and controls the hot gas valve to close when the actual temperature is greater than or equal to the preset temperature.

[0194] The refrigeration system control device provided in the embodiments of the present invention can execute the refrigeration system control method provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of the method execution.

[0195] The technical solution of this invention also provides a battery testing device. Figure 10 This is a schematic diagram of the structure of a battery testing device provided in an embodiment of the present invention, for reference. Figure 3 and Figure 10 The battery testing equipment includes a battery testing device 801, a cooling system 802, and a cooling system control device 803 provided in any of the above embodiments. The battery testing device 801 is connected to the power battery 804 and is used to acquire parameter information of the power battery 804 at different temperatures. The cooling system control device 803 is connected to the cooling system 802 and is used to control the operation of the cooling system 802 when the temperature of the power battery 804 is greater than the temperature threshold.

[0196] Among them, the refrigeration system 802 is Figure 3 The refrigeration system shown is as follows: Figure 3 As shown, the refrigeration system 802 also includes a main solenoid valve 160, through which the condenser 120 is connected to the electronic expansion valve 130. By setting the main solenoid valve 160, it closes when the refrigeration system stops, preventing refrigerant accumulation on the low-pressure side even if the electronic expansion valve 130 opens, thus further avoiding liquid slugging and oil shortage problems in the compressor 110. The refrigeration system 802 also includes a heater 170, which heats the test chamber when the temperature is low, achieving offsetting regulation of heat and cold to maintain a relatively constant test chamber temperature. Pressure gauges or pressure sensors can also be installed in the refrigeration system 802 to monitor the pressure in the pipelines.

[0197] Specifically, when testing the power battery 804, the battery testing device 801 controls the power battery 804 to charge and discharge. By setting the ambient temperature of the power battery 804, the battery testing device 801 acquires parameter information of the power battery 804 at different temperatures. This parameter information includes, for example, temperature, current, voltage, and remaining battery capacity. This allows for testing of the battery's quality, charge / discharge performance, lifespan, and long-term reliability. The battery testing device 801 is connected to a cooling system control device 803. The battery testing device 801 can send the temperature information of the power battery 804 to the cooling system control device 803. During the test, if the temperature of the power battery 804 exceeds a temperature threshold, the cooling system control device 803 controls the cooling system 802 to operate, thereby cooling the battery and replicating the scenario of real-world application, thus improving the accuracy of the power battery 804 test.

[0198] Furthermore, when the first difference between the actual temperature of the test chamber 150 and the evaporator outlet temperature is less than a first temperature judgment value, or when the first difference is greater than a second temperature judgment value, the refrigeration system control device 803 adjusts the opening of the electronic expansion valve 130 according to the target opening degree, so that the opening degree of the electronic expansion valve 130 reaches the target opening degree, thereby ensuring that the difference between the actual temperature of the test chamber 150 and the set temperature of the test chamber is within the preset difference range. Therefore, the opening degree of the electronic expansion valve 130 is controlled according to actual needs, maintaining the opening degree of the electronic expansion valve 130 in a suitable state, thereby avoiding liquid slugging and oil shortage problems in the compressor 110. The refrigeration system control device 803 controls the liquid injection valve 210 to open or close based on the actual discharge temperature range of the compressor 110 and the relationship between the actual discharge temperature and time. Alternatively, the refrigeration system control device 803 controls the liquid injection valve 210 to open or close based on the actual suction temperature range of the compressor 110 and the relationship between the actual suction temperature and time. This ensures that the liquid injection valve 210 opens as needed, preventing excessive liquid injection that could cause liquid slugging in the compressor 110 and improving the reliability of the refrigeration system.

[0199] In summary, by controlling the opening of the electronic expansion valve 130 as needed through the refrigeration system control device 803, and controlling the opening or closing of the liquid injection valve 210 as needed, excessive liquid injection is avoided, which could lead to liquid slugging and oil shortage problems in the compressor 110. This ensures that the refrigeration system 802 works normally, thereby enabling the battery testing equipment to operate normally and improving the accuracy of testing the power battery 804.

[0200] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and no limitation is imposed herein.

[0201] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for controlling a refrigeration system, characterized in that, The refrigeration system includes a main refrigeration circuit; the main refrigeration circuit includes a compressor, a condenser, an electronic expansion valve, and an evaporator connected in series. The evaporator is located in the test chamber; The control method includes: When the duration for which the refrigeration system maintains the current actual temperature of the test chamber is greater than or equal to a first preset duration, or when the duration for which the electronic expansion valve maintains its current opening is greater than or equal to a second preset duration, the target opening of the electronic expansion valve is updated. When the first difference between the actual temperature of the test chamber and the evaporator outlet temperature is less than the first temperature judgment value, or the first difference is greater than the second temperature judgment value, the opening of the electronic expansion valve is adjusted according to the target opening to make the difference between the actual temperature of the test chamber and the set temperature of the test chamber within the preset difference range. When the first difference is greater than or equal to the first temperature determination value and less than or equal to the second temperature determination value, the electronic expansion valve maintains the current opening for a second preset duration. The refrigeration system further includes a liquid injection line; the liquid injection line is connected between the inlet of the compressor and the inlet of the evaporator, and the liquid injection line includes a liquid injection valve and a first capillary tube connected in series; The control method further includes: Determine the first deviation range within which the second difference between the actual exhaust temperature value and the target exhaust temperature value of the compressor lies; From the first preset relationship, find the target state of the spray valve corresponding to the first deviation range under the current operating condition; wherein, the current operating condition includes the actual temperature of the test chamber and the current ambient temperature of the environment where the refrigeration system is located, and the first preset relationship is the correspondence between the actual temperature, the current ambient temperature, the first deviation range and the target state; The spray valve is opened or closed according to the target state; And / or, Determine the second deviation range in which the third difference between the actual intake temperature value and the target intake temperature value of the compressor falls; From the second preset relationship, find the target state of the injection valve corresponding to the second deviation range under the current operating condition; wherein, the second preset relationship is the correspondence between the actual temperature, the current ambient temperature, the second deviation range and the target state; The spray valve is opened or closed according to the target state.

2. The method according to claim 1, characterized in that, When the first difference between the actual temperature of the test chamber and the evaporator outlet temperature is less than a first temperature judgment value, or the first difference is greater than a second temperature judgment value, the opening of the electronic expansion valve is adjusted according to the target opening degree to ensure that the difference between the actual temperature of the test chamber and the set temperature of the test chamber is within a preset difference range, including: When the first difference is less than the first temperature judgment value, the opening of the electronic expansion valve is reduced according to the opening adjustment rate until the opening of the electronic expansion valve reaches the target opening, so that the difference between the actual temperature of the test chamber and the set temperature of the test chamber is within the preset difference range. When the first difference is greater than the second temperature determination value, the opening of the electronic expansion valve is increased according to the opening adjustment rate until the opening of the electronic expansion valve reaches the target opening, so that the difference between the actual temperature of the test chamber and the set temperature of the test chamber is within the preset difference range.

3. The method according to claim 2, characterized in that, Before reducing the opening of the electronic expansion valve according to the opening adjustment rate when the first difference is less than the first temperature determination value, the method further includes: The opening adjustment rate of the electronic expansion valve is calculated based on the target opening degree, the current opening degree of the electronic expansion valve, the start time of the opening adjustment of the electronic expansion valve, and the end time of the opening adjustment of the electronic expansion valve.

4. The method according to claim 1, characterized in that, The control method further includes: Based on the actual exhaust temperature range of the compressor and the relationship between the actual exhaust temperature and time, the liquid injection valve is controlled to open or close. And / or, based on the actual suction temperature range of the compressor and the relationship between the actual suction temperature and time, control the liquid injection valve to open or close.

5. The method according to claim 4, characterized in that, Before controlling the opening or closing of the injection valve based on the actual exhaust temperature range of the compressor and the relationship between the actual exhaust temperature and time, the method further includes: Obtain the first actual exhaust temperature value of the compressor at the first moment and the second actual exhaust temperature value of the compressor at the second moment; Determine the exhaust temperature range in which the first actual exhaust temperature value or the second actual exhaust temperature value is located; wherein, the exhaust temperature range includes at least two ranges determined based on the minimum exhaust temperature value, at least one intermediate exhaust temperature value, and the maximum exhaust temperature value, wherein the intermediate exhaust temperature value is greater than or equal to the minimum exhaust temperature value and less than or equal to the maximum exhaust temperature value; The relationship between the actual exhaust temperature value and time is determined based on the ratio of the first temperature difference between the second actual exhaust temperature value and the first actual exhaust temperature value to the first time period; wherein, the first time period is the time difference between the second time moment and the first time moment. Before controlling the opening or closing of the injection valve based on the actual suction temperature range of the compressor and the relationship between the actual suction temperature and time, the method further includes: Obtain the first actual suction temperature value of the compressor at the third time point and the second actual suction temperature value of the compressor at the fourth time point; Determine the range of inhalation temperature where the first actual inhalation temperature or the second actual inhalation temperature value falls; The relationship between the actual inhalation temperature value and time is determined based on the ratio of the second temperature difference between the second actual inhalation temperature value and the first actual inhalation temperature value to the second time period; wherein, the second time period is the time difference between the fourth time point and the third time point.

6. The method according to claim 4, characterized in that, The step of controlling the opening or closing of the injection valve based on the actual exhaust temperature range of the compressor and the relationship between the actual exhaust temperature and time includes: The temperature range between the minimum and maximum exhaust temperatures is divided into a first exhaust temperature range and a second exhaust temperature range; wherein, the first exhaust temperature range is from the minimum exhaust temperature to the median exhaust temperature, and the second exhaust temperature range is from the median exhaust temperature to the maximum exhaust temperature. If the actual exhaust temperature value is within the first exhaust temperature range, and the actual exhaust temperature value decreases over time, then the injection valve is controlled to close. If the actual exhaust temperature value is within the second exhaust temperature range, and the actual exhaust temperature value increases with time, then the injection valve is controlled to open.

7. The method according to claim 4, characterized in that, The step of controlling the opening or closing of the injection valve based on the actual suction temperature range of the compressor and the relationship between the actual suction temperature and time includes: The temperature values ​​between the minimum and maximum inhalation temperature are divided into a first inhalation temperature range and a second inhalation temperature range; wherein, the first inhalation temperature range is from the minimum inhalation temperature to the median inhalation temperature, and the second inhalation temperature range is from the median inhalation temperature to the maximum inhalation temperature. If the actual inhalation temperature value is within the first inhalation temperature range, and the actual inhalation temperature value decreases over time, then the spray valve is controlled to close. If the actual intake temperature value is within the second intake temperature range, and the actual intake temperature value increases with time, then the spray valve is controlled to open.

8. The method according to claim 1, characterized in that, The refrigeration system also includes a hot gas bypass supply line, which is connected between the outlet of the compressor and the inlet of the evaporator. The hot gas bypass supply line includes a hot gas valve and a second capillary tube. The control method further includes: When the actual temperature of the test chamber is lower than the preset temperature of the test chamber, the hot gas valve is controlled to open; When the actual temperature is greater than or equal to the preset temperature, the hot gas valve is controlled to close.

9. A refrigeration system control device, characterized in that, The refrigeration system includes a main refrigeration circuit; the main refrigeration circuit includes a compressor, a condenser, an electronic expansion valve, and an evaporator connected in series. The evaporator is located in the test chamber; The refrigeration system control device includes: The target opening update module is used to update the target opening of the electronic expansion valve when the duration for which the refrigeration system maintains the current actual temperature of the test chamber is greater than or equal to a first preset duration, or when the duration for which the electronic expansion valve maintains the current opening is greater than or equal to a second preset duration. The opening adjustment module is used to adjust the opening of the electronic expansion valve according to the target opening when the first difference between the actual temperature of the test chamber and the evaporator outlet temperature is less than a first temperature judgment value, or the first difference is greater than a second temperature judgment value, so that the difference between the actual temperature of the test chamber and the set temperature of the test chamber is within a preset difference range. An opening maintenance module is used to maintain the electronic expansion valve at its current opening for a second preset duration when the first difference is greater than or equal to the first temperature determination value and less than or equal to the second temperature determination value. The refrigeration system control unit also includes a liquid injection valve control module, which is used for: Determine the first deviation range within which the second difference between the actual exhaust temperature value and the target exhaust temperature value of the compressor lies; From the first preset relationship, find the target state of the spray valve corresponding to the first deviation range under the current operating condition; wherein, the current operating condition includes the actual temperature of the test chamber and the current ambient temperature of the environment where the refrigeration system is located, and the first preset relationship is the correspondence between the actual temperature, the current ambient temperature, the first deviation range and the target state; The spray valve is opened or closed according to the target state; And / or, Determine the second deviation range in which the third difference between the actual intake temperature value and the target intake temperature value of the compressor falls; From the second preset relationship, find the target state of the injection valve corresponding to the second deviation range under the current operating condition; wherein, the second preset relationship is the correspondence between the actual temperature, the current ambient temperature, the second deviation range and the target state; The spray valve is opened or closed according to the target state.

10. A power battery testing device, characterized in that, Includes a battery testing device, a refrigeration system, and a refrigeration system control device as described in claim 9; The battery testing device is connected to the power battery, and the battery testing device is used to obtain parameter information of the power battery at different temperatures; The refrigeration system control device is connected to the refrigeration system and is used to control the operation of the refrigeration system when the temperature of the power battery is greater than the temperature threshold.

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