An energy-saving control method for ultra-low pressure ratio operation of an energy storage battery liquid cooling unit

Abstract

The application provides an energy-saving control method for an ultra-low pressure ratio operation of an energy storage battery liquid cooling unit. A target value of a return gas pressure saturation temperature is calculated based on working parameters, and a control parameter of an electronic expansion valve is determined based on a relationship between the target value of the return gas pressure saturation temperature and the target value. A target value of an exhaust gas pressure saturation temperature is calculated based on the working parameters, and a control parameter of a fan is determined based on a relationship between the target value of the exhaust gas pressure saturation temperature and the target value. The return gas pressure is always operated at a reasonable high value. The exhaust gas pressure is controlled by the fan speed, and the target value of the exhaust gas pressure is calculated in real time based on the ambient temperature, the compressor pressure ratio and the return gas pressure. The exhaust gas pressure is always operated in a reasonable range. In the low temperature season, the system can be operated at an ultra-low pressure ratio, the power consumption of the compressor can be greatly reduced, the energy efficiency can be improved, and energy saving and emission reduction can be realized.

Description

Technical Field

[0001] This invention relates to the field of energy-saving technology for generator units, and in particular to an energy-saving control method for ultra-low pressure ratio operation of a liquid-cooled energy storage battery generator unit. Background Technology

[0002] The energy structure is undergoing rapid transformation, and energy storage batteries, as a form of new energy, are currently experiencing rapid application development, such as in residential storage, commercial and industrial storage, and energy storage power stations. Liquid cooling units, as a commonly used device for thermal management of energy storage batteries, are also in a period of rapid development. Figure 2 As shown, the structure of the energy storage battery liquid cooling unit system mainly consists of a compressor, low-pressure sensor, return gas temperature sensor, return liquid temperature sensor, supply liquid temperature sensor, medium heat exchanger, electronic expansion valve, ambient temperature sensor, external heat exchanger, fan, high-pressure sensor, and exhaust temperature sensor. It uses vapor compression refrigeration to generate coolant, which is supplied to the energy storage battery heat dissipation system to remove heat and maintain the reasonable temperature environment required for battery operation.

[0003] Due to the heat dissipation requirements of energy storage batteries, liquid-cooled units generally operate in cooling mode throughout the year. In low-temperature seasons, there are natural cold sources outdoors, but current liquid-cooled units, in order to ensure compressor reliability, still maintain the compressor discharge pressure at a relatively high value during low-temperature seasons. This results in a high compressor pressure ratio, high power consumption, low energy efficiency, and increased operating costs. Traditional solutions control the fan speed based on the discharge pressure. To ensure the reliability of compressor operation, the discharge pressure is always maintained at a relatively high value. In low-temperature environments, the discharge pressure is increased by reducing the fan speed or turning it off, resulting in a high compressor operating pressure ratio, high power consumption, and low energy efficiency. Summary of the Invention

[0004] This invention provides an energy-saving control method for ultra-low pressure ratio operation of liquid-cooled energy storage battery units, in order to solve the problems mentioned in the background art.

[0005] An energy-saving control method for ultra-low pressure ratio operation of a liquid-cooled energy storage battery unit includes:

[0006] S1: Obtain the structural distribution of the energy storage battery liquid cooling unit system, and collect the operating parameters of the battery liquid cooling unit system from the structural distribution;

[0007] S2: Based on the operating parameters, calculate the target value of the return gas pressure saturation temperature, and based on the relationship between the return gas pressure saturation temperature value and the return gas pressure saturation temperature value, determine the control parameters for the electronic expansion valve.

[0008] S3: Based on the operating parameters, calculate the target value of the exhaust pressure saturation temperature, and based on the relationship between the exhaust pressure saturation temperature value and the exhaust pressure saturation temperature value, determine the control parameters for the fan.

[0009] Preferably, in step S1, the structural distribution of the energy storage battery liquid cooling unit system is obtained, including a compressor, a liquid supply pipe connected to the compressor, the other end of the liquid supply pipe connected to an external heat exchanger, an exhaust temperature sensor and a high pressure sensor installed on the liquid supply pipe, a fan and an ambient temperature sensor installed on the external heat exchanger, a connecting pipe connected to the external heat exchanger, the other end of the connecting pipe connected to a medium heat exchanger, an electronic expansion valve installed on the connecting pipe, a return liquid pipe connected to the medium heat exchanger, the other end of the return liquid pipe connected to the compressor, a low pressure sensor and a return gas temperature sensor installed on the return liquid pipe, and a return liquid temperature sensor and a liquid supply temperature sensor installed on the medium heat exchanger.

[0010] Preferably, in step S1, the operating parameters of the battery liquid cooling unit system are collected from the structural distribution, including:

[0011] The return gas pressure of the energy storage battery liquid cooling unit system is collected from the low-pressure sensor, the exhaust pressure of the energy storage battery liquid cooling unit system is collected from the high-pressure sensor, the return liquid temperature is collected from the return liquid temperature sensor, the supply liquid temperature is collected from the supply liquid temperature sensor, the return gas pressure and temperature value is collected from the return gas temperature sensor, the exhaust temperature value is collected from the exhaust temperature sensor, and the ambient temperature value is collected from the ambient temperature sensor.

[0012] Preferably, in step S2, calculating the target value of the return gas pressure saturation temperature based on the operating parameters includes:

[0013] Based on the aforementioned operating parameters, the target value of the return gas pressure saturation temperature is calculated according to the following formula;

[0014] Tes = To - x * Δt1 / b

[0015] K = Pd - Tc

[0016] Where Tes represents the target value of return gas pressure saturation temperature, To represents the liquid supply temperature value, and K represents the exhaust superheat.

[0017] When the compressor is off, x returns to its default value. After the compressor is on, it is corrected in real time based on the exhaust superheat, specifically:

[0018] When the exhaust superheat is greater than c, x is reduced by 1 from the current real-time value in each adjustment cycle. The corrected Tes value is generally no higher than the Tes value calculated by the default value of x plus 4℃.

[0019] When c ≥ exhaust superheat ≥ c - Δt2, x remains unchanged at its current real-time value;

[0020] When c-Δt2>exhaust superheat, x is increased by 1 in each adjustment cycle. The corrected Tes value is generally not lower than the Tes value calculated by subtracting 4℃ from the default value of x.

[0021] Preferably, in step S2, determining the control parameters for the electronic expansion valve based on the relationship between the return gas pressure saturation temperature value and the return gas pressure saturation temperature value includes:

[0022] When the saturation temperature of the return gas pressure is greater than the sum of the saturation temperature of the return gas pressure and the hysteresis temperature, the electronic expansion valve is closed.

[0023] When the return gas pressure saturation temperature value is equal to the sum of the return gas pressure saturation temperature value and the hysteresis temperature, the current opening degree of the electronic expansion valve remains unchanged.

[0024] When the return gas pressure saturation temperature is less than the sum of the return gas pressure saturation temperature and the hysteresis temperature, the electronic expansion valve is opened wider.

[0025] Preferably, in step S3, calculating the target value of the exhaust pressure saturation temperature based on the operating parameters includes:

[0026] Based on the aforementioned operating parameters, the target value of the exhaust pressure saturation temperature is calculated using the following formula;

[0027] Tcs = max(T1 + Δt3, y * Pes)

[0028] Where Tcs represents the target value of exhaust pressure saturation temperature, T1 represents the ambient temperature value, Pes represents the target value of return gas pressure saturation temperature, and the y value is taken according to the minimum pressure ratio allowed by the compressor specification, which is generally 1.1 to 1.3.

[0029] When compressor 1 is off, the y-value returns to its default value. After the compressor is on, the y-value is corrected according to the return gas pressure saturation temperature value Te.

[0030] When Te < Tes-a, and the opening of the electronic expansion valve exceeds 70% of its maximum opening, the y value is increased by 0.1 based on the current real-time value for each adjustment cycle. The corrected y value should always be limited to the maximum correction value based on the default value. Generally, the corrected y value does not exceed 1.5 to 1.8.

[0031] When Tes≥Te≥Tes-a, the y value remains the current real-time value;

[0032] When Te > Tes, the y value is reduced by 0.1 from the current real-time value in each adjustment cycle. The corrected y value is always not less than the default value, and generally the corrected y value is ≥1.1.

[0033] Preferably, in step S3, determining the control parameters for the fan based on the relationship between the exhaust pressure saturation temperature value and the exhaust pressure saturation temperature value includes:

[0034] When the exhaust pressure saturation temperature is greater than the sum of the exhaust pressure saturation temperature and the hysteresis temperature, the fan speed is increased.

[0035] When the exhaust pressure saturation temperature value is equal to the sum of the exhaust pressure saturation temperature value and the hysteresis temperature, the speed of the fan is kept constant.

[0036] When the exhaust pressure saturation temperature is less than the sum of the exhaust pressure saturation temperature and the hysteresis temperature, the fan speed is reduced.

[0037] Preferred options also include:

[0038] Obtain the compressor's operating pressure ratio under the control parameters of the electronic expansion valve and the fan.

[0039] Based on the relationship between the operating pressure ratio and the preset operating pressure ratio, the control parameters are fine-tuned.

[0040] Preferably, the step of fine-tuning the control parameters based on the relationship between the operating pressure ratio and the preset operating pressure ratio includes:

[0041] When the operating pressure ratio is less than or equal to the preset operating pressure ratio, the control parameters are not adjusted;

[0042] When the operating pressure ratio is greater than the preset operating pressure ratio, the control parameters to be adjusted when the operating pressure ratio is greater than the preset operating pressure ratio are obtained, and the control parameters to be adjusted are fine-tuned based on the operating pressure ratio-parameter curve.

[0043] Preferably, based on the operating pressure ratio-parameter curve, the control parameter to be adjusted is fine-tuned, including:

[0044] Based on the real-time operating parameters and real-time control parameters of the energy storage battery liquid cooling unit system, and by monitoring the operating pressure ratio under the real-time operating parameters and real-time control parameters, an operating pressure ratio-parameter curve is established.

[0045] The highest operating pressure ratio and its corresponding first parameter, and the lowest operating pressure ratio and its corresponding second parameter are obtained from the operating pressure ratio-parameter curve. Based on the first parameter, the optimal parameter relationship between the first operating parameter and the first control parameter is determined. Based on the second parameter, the worst parameter relationship between the second operating parameter and the second control parameter is determined.

[0046] Determine the first operating pressure ratio difference and the second operating pressure ratio difference between the operating pressure ratio and the highest operating pressure and the lowest operating pressure ratio, respectively;

[0047] Based on the first operating pressure differential ratio, the adjustment range of the control parameters is determined. Based on the worst-case parameter relationship and the operating parameters of the operating pressure ratio, the adjustment weight of the control parameters is determined. Based on the adjustment range and the adjustment weight of the control parameters, the fine-tuning data of the control parameters to be adjusted is determined.

[0048] Based on the second operating pressure differential ratio and the optimal parameter relationship, the fine-tuning data is verified and corrected to determine whether the parameter relationship between the control parameters adjusted according to the fine-tuning data and the operating parameters of the operating pressure ratio is within a preset range from the optimal parameter relationship.

[0049] If so, fine-tune the control parameters to be adjusted according to the fine-tuning data;

[0050] Otherwise, the fine-tuning data is corrected based on the second operating differential pressure ratio.

[0051] Compared with the prior art, the present invention has achieved the following beneficial effects:

[0052] By acquiring the structural distribution of the energy storage battery liquid cooling unit system and collecting its operating parameters from this distribution, the target value of the return gas pressure saturation temperature is calculated based on these parameters. Furthermore, based on the relationship between the return gas pressure saturation temperature and the target value of the exhaust pressure saturation temperature, the control parameters for the electronic expansion valve are determined. Similarly, based on these operating parameters, the target value of the exhaust pressure saturation temperature is calculated, and based on the relationship between the exhaust pressure saturation temperature and the target value of the exhaust pressure saturation temperature, the control parameters for the fan are determined, ensuring that the return gas pressure always operates at a reasonably high value. The exhaust pressure is controlled by the fan speed. The target exhaust pressure value is calculated in real-time from the ambient temperature, compressor pressure ratio, and return gas pressure, ensuring that the exhaust pressure always operates within a reasonable range. In low-temperature seasons, the system can achieve ultra-low pressure ratio operation, significantly reducing compressor power consumption, improving energy efficiency, and achieving energy conservation and emission reduction.

[0053] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures particularly pointed out in this application.

[0054] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0055] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0056] Figure 1 This is a flowchart of an energy-saving control method for ultra-low pressure ratio operation of a liquid-cooled energy storage battery unit according to an embodiment of the present invention;

[0057] Figure 2 This is a structural distribution diagram of the energy storage battery liquid cooling unit system in an embodiment of the present invention;

[0058] Figure 3 This is a flowchart illustrating the fine-tuning of control parameters in an embodiment of the present invention. Detailed Implementation

[0059] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0060] Example 1:

[0061] Based on Example 1, this embodiment of the invention provides an energy-saving control method for ultra-low pressure ratio operation of an energy storage battery liquid-cooled unit, such as... Figure 1 As shown, it includes:

[0062] S1: Obtain the structural distribution of the energy storage battery liquid cooling unit system, and collect the operating parameters of the battery liquid cooling unit system from the structural distribution;

[0063] S2: Based on the operating parameters, calculate the target value of the return gas pressure saturation temperature, and based on the relationship between the return gas pressure saturation temperature value and the return gas pressure saturation temperature value, determine the control parameters for the electronic expansion valve 7.

[0064] S3: Based on the operating parameters, calculate the target value of the exhaust pressure saturation temperature, and based on the relationship between the exhaust pressure saturation temperature value and the exhaust pressure saturation temperature value, determine the control parameters for the fan 10.

[0065] In this embodiment, the return gas pressure saturation temperature value is calculated based on the return gas pressure value.

[0066] In this embodiment, the exhaust pressure saturation temperature value is calculated based on the exhaust pressure value.

[0067] In this embodiment, the electronic expansion valve controls the return gas pressure, and the fan speed controls the exhaust pressure. Specifically, the control parameters for the electronic expansion valve 7 are the control of the opening degree of the electronic expansion valve, and the control parameters for the fan 10 are the control of the fan speed.

[0068] In this embodiment, the present invention proposes an energy-saving control method for ultra-low pressure ratio operation of an energy storage liquid-cooled unit. The method controls the return gas pressure via an electronic expansion valve, with the target value calculated in real-time from the supply liquid temperature and exhaust superheat, ensuring the return gas pressure always operates at a reasonably high value. The method also controls the exhaust pressure via fan speed, with the target value calculated in real-time from the ambient temperature, compressor pressure ratio, and return gas pressure, ensuring the exhaust pressure always operates within a reasonable range. In low-temperature seasons, the system can achieve ultra-low pressure ratio operation, significantly reducing compressor power consumption, improving energy efficiency, and achieving energy conservation and emission reduction.

[0069] In this embodiment, the operating parameters of the battery liquid cooling unit system include the detection parameters of each sensor.

[0070] The beneficial effects of the above design scheme are as follows: By acquiring the structural distribution of the energy storage battery liquid cooling unit system and collecting the operating parameters of the battery liquid cooling unit system from the structural distribution, the target value of the return gas pressure saturation temperature is calculated based on the operating parameters. Based on the relationship between the return gas pressure saturation temperature value and the return gas pressure saturation temperature value, the control parameters of the electronic expansion valve 7 are determined. Based on the operating parameters, the target value of the exhaust pressure saturation temperature is calculated. Based on the relationship between the exhaust pressure saturation temperature value and the exhaust pressure saturation temperature value, the control parameters of the fan 10 are determined, ensuring that the return gas pressure always operates at a reasonable high value. By controlling the exhaust pressure through the fan speed, the target value of the exhaust pressure is calculated in real time from the ambient temperature, compressor pressure ratio, and return gas pressure, ensuring that the exhaust pressure always operates within a reasonable range. In low-temperature seasons, the system can achieve ultra-low pressure ratio operation, significantly reducing compressor power consumption, improving energy efficiency, and achieving energy saving and emission reduction.

[0071] Example 2:

[0072] Based on Example 1, this embodiment of the invention provides an energy-saving control method for ultra-low pressure ratio operation of an energy storage battery liquid-cooled unit, such as... Figure 2As shown in S1, the structural distribution of the energy storage battery liquid cooling unit system is obtained, including a compressor 1, a liquid supply pipe connected through the compressor 1, the other end of the liquid supply pipe connected through an outer heat exchanger 9, an exhaust temperature sensor 12 and a high pressure sensor 11 are also installed on the liquid supply pipe, a fan 10 and an ambient temperature sensor 8 are installed on the outer heat exchanger 9, a connecting pipe is also connected through the outer heat exchanger 9, the other end of the connecting pipe is connected through a medium heat exchanger 6, an electronic expansion valve 7 is installed on the connecting pipe, a return liquid pipe is connected through the medium heat exchanger 6, the other end of the return liquid pipe is connected through the compressor 1, a low pressure sensor 2 and a return gas temperature sensor 3 are installed on the return liquid pipe, and a return liquid temperature sensor 4 and a liquid supply temperature sensor 5 are also installed on the medium heat exchanger 6.

[0073] The beneficial effects of the above design scheme are: it provides a structural distribution for the liquid cooling unit system of energy storage batteries, and provides a structural basis for energy-saving control of ultra-low pressure ratio operation.

[0074] Example 3:

[0075] Based on Example 2, this embodiment of the invention provides an energy-saving control method for ultra-low pressure ratio operation of an energy storage battery liquid cooling unit. In step S1, the operating parameters of the battery liquid cooling unit system are collected from the structural distribution, including:

[0076] The return gas pressure of the energy storage battery liquid cooling unit system is collected from the low-pressure sensor 2, the exhaust pressure of the energy storage battery liquid cooling unit system is collected from the high-pressure sensor 11, the return liquid temperature is collected from the return liquid temperature sensor 4, the supply liquid temperature is collected from the supply liquid temperature sensor 5, the return gas pressure and temperature value is collected from the return gas temperature sensor 3, the exhaust temperature value is collected from the exhaust temperature sensor 12, and the ambient temperature value is collected from the ambient temperature sensor 8.

[0077] The beneficial effects of the above design scheme are: by collecting the parameters of each sensor, the operating parameters are obtained, providing a parameter basis for energy-saving control of ultra-low pressure ratio operation.

[0078] Example 4:

[0079] Based on Example 1, this embodiment of the invention provides an energy-saving control method for ultra-low pressure ratio operation of an energy storage battery liquid cooling unit. In step S2, based on the operating parameters, the target value of the return gas pressure saturation temperature is calculated, including:

[0080] Based on the aforementioned operating parameters, the target value of the return gas pressure saturation temperature is calculated according to the following formula;

[0081] Tes = To - x * Δt1 / b

[0082] K = Pd - Tc

[0083] Where Tes represents the target value of return gas pressure saturation temperature, To represents the liquid supply temperature value, and K represents the exhaust superheat.

[0084] When compressor 1 is off, x returns to its default value. After compressor 1 is on, x is adjusted in real time based on the exhaust superheat, specifically:

[0085] When the exhaust superheat is greater than c, x is reduced by 1 from the current real-time value in each adjustment cycle. The corrected Tes value is generally no higher than the Tes value calculated by the default value of x plus 4℃.

[0086] When c ≥ exhaust superheat ≥ c - Δt2, x remains unchanged at its current real-time value;

[0087] When c-Δt2>exhaust superheat, x is increased by 1 in each adjustment cycle. The corrected Tes value is generally not lower than the Tes value calculated by subtracting 4℃ from the default value of x.

[0088] In this embodiment, Δt1 is generally taken as 2 to 5, b is generally taken as 10, and the default value of x is generally equal to b; the values ​​of c and Δt2 must meet the reliability requirements in the compressor specification, and at the same time, it is not advisable to leave too large a margin, so as to keep the return gas pressure saturation temperature value at a high value as much as possible.

[0089] The beneficial effects of the above design scheme are: by using the above control methods to keep the return gas pressure saturation temperature value at a reasonable high value, the output speed of the compressor can be reduced, power consumption can be reduced, and the target value of the return gas pressure saturation temperature can be calculated based on the working parameters of the energy storage battery liquid cooling unit system, providing a numerical basis for energy-saving control of ultra-low pressure ratio operation.

[0090] Example 5:

[0091] Based on Example 1, this embodiment of the invention provides an energy-saving control method for ultra-low pressure ratio operation of an energy storage battery liquid cooling unit. In step S2, the control parameters for the electronic expansion valve 7 are determined based on the relationship between the return gas pressure saturation temperature value and the return gas pressure saturation temperature value, including:

[0092] When the saturation temperature of the return gas pressure is greater than the sum of the saturation temperature of the return gas pressure and the hysteresis temperature, the electronic expansion valve 7 is closed.

[0093] When the return gas pressure saturation temperature value is equal to the sum of the return gas pressure saturation temperature value and the hysteresis temperature, the current opening degree of the electronic expansion valve 7 remains unchanged.

[0094] When the return gas pressure saturation temperature is less than the sum of the return gas pressure saturation temperature and the hysteresis temperature, the electronic expansion valve 7 is opened wider.

[0095] The beneficial effects of the above design scheme are: by using the above control methods to keep the return gas pressure saturation temperature value at a reasonable high value, the output speed of the compressor can be reduced, power consumption can be reduced, and ultra-low pressure ratio operation can be guaranteed from the perspective of return gas pressure.

[0096] Example 6:

[0097] Based on Example 1, this embodiment of the invention provides an energy-saving control method for ultra-low pressure ratio operation of an energy storage battery liquid cooling unit. In step S3, based on the operating parameters, the target value of the exhaust pressure saturation temperature is calculated, including:

[0098] Based on the aforementioned operating parameters, the target value of the exhaust pressure saturation temperature is calculated using the following formula;

[0099] Tcs = max(T1 + Δt3, y * Pes)

[0100] Where Tcs represents the target value of exhaust pressure saturation temperature, T1 represents the ambient temperature value, Pes represents the target value of return gas pressure saturation temperature, and the y value is taken according to the minimum pressure ratio allowed by the compressor specification, which is generally 1.1 to 1.3.

[0101] When compressor 1 is off, the y-value returns to its default value. When compressor 1 is on, the y-value is corrected according to the return gas pressure saturation temperature value Te.

[0102] When Te < Tes-a, and the opening of the electronic expansion valve exceeds 70% of its maximum opening, the y value is increased by 0.1 based on the current real-time value for each adjustment cycle. The corrected y value should always be limited to the maximum correction value based on the default value. Generally, the corrected y value does not exceed 1.5 to 1.8.

[0103] When Tes≥Te≥Tes-a, the y value remains the current real-time value;

[0104] When Te > Tes, the y value is reduced by 0.1 from the current real-time value in each adjustment cycle. The corrected y value is always not less than the default value, and generally the corrected y value is ≥1.1.

[0105] In this embodiment, Δt3 is generally taken as 5 to 10, and a is generally taken as 0 to 2.

[0106] The beneficial effects of the above design scheme are: by calculating the target value of exhaust pressure saturation temperature based on the working parameters of the energy storage battery liquid cooling unit system, a numerical basis is provided for energy-saving control of ultra-low pressure ratio operation.

[0107] Example 7:

[0108] Based on Example 1, this embodiment of the invention provides an energy-saving control method for ultra-low pressure ratio operation of an energy storage battery liquid cooling unit. In step S3, the control parameters for the fan 10 are determined based on the relationship between the exhaust pressure saturation temperature value and the exhaust pressure saturation temperature value, including:

[0109] When the exhaust pressure saturation temperature value is greater than the sum of the exhaust pressure saturation temperature value and the hysteresis temperature, the fan 10 is controlled to increase its speed.

[0110] When the exhaust pressure saturation temperature value is equal to the sum of the exhaust pressure saturation temperature value and the hysteresis temperature, the speed of the fan 10 is kept constant.

[0111] When the exhaust pressure saturation temperature is less than the sum of the exhaust pressure saturation temperature and the hysteresis temperature, the fan 10 is controlled to reduce its speed.

[0112] The beneficial effects of the above design scheme are: through the above control methods, the exhaust pressure is always kept within a reasonable range, especially in low temperature seasons, it can achieve ultra-low pressure ratio operation, significantly reduce compressor power consumption, improve operating efficiency, and ensure ultra-low pressure ratio operation from the perspective of exhaust pressure.

[0113] Example 8:

[0114] Based on Example 1, this embodiment of the invention provides an energy-saving control method for ultra-low pressure ratio operation of an energy storage battery liquid-cooled unit, such as... Figure 3 As shown, it also includes:

[0115] The operating pressure ratio of compressor 1 is obtained under the control parameters of electronic expansion valve 7 and fan 10.

[0116] Based on the relationship between the operating pressure ratio and the preset operating pressure ratio, the control parameters are fine-tuned.

[0117] The beneficial effects of the above design scheme are: by obtaining the operating pressure ratio of the compressor 1 under the control parameters of the electronic expansion valve 7 and the fan 10, and based on the relationship between the operating pressure ratio and the preset operating pressure ratio, the control parameters are finely adjusted to achieve ultra-low pressure ratio operation of the energy storage battery liquid cooling unit.

[0118] Example 9:

[0119] Based on Example 8, this embodiment of the invention provides an energy-saving control method for ultra-low pressure ratio operation of an energy storage battery liquid cooling unit. The method involves fine-tuning control parameters based on the relationship between the operating pressure ratio and a preset operating pressure ratio, including:

[0120] When the operating pressure ratio is less than or equal to the preset operating pressure ratio, the control parameters are not adjusted;

[0121] When the operating pressure ratio is greater than the preset operating pressure ratio, the control parameters to be adjusted when the operating pressure ratio is greater than the preset operating pressure ratio are obtained, and the control parameters to be adjusted are fine-tuned based on the operating pressure ratio-parameter curve.

[0122] In this embodiment, the operating pressure ratio-parameter curve is obtained based on the operating status of the energy storage battery liquid cooling unit.

[0123] The beneficial effects of the above design scheme are: by obtaining the control parameters to be adjusted when the operating pressure ratio is greater than the preset operating pressure ratio, and fine-tuning the control parameters to be adjusted based on the operating pressure ratio-parameter curve, the energy storage battery liquid cooling unit system can always maintain ultra-low pressure ratio operation and reduce energy consumption.

[0124] Example 10:

[0125] Based on Example 9, this embodiment of the invention provides an energy-saving control method for ultra-low pressure ratio operation of an energy storage battery liquid cooling unit. Based on the operating pressure ratio-parameter curve, the method fine-tunes the control parameters to be adjusted, including:

[0126] Based on the real-time operating parameters and real-time control parameters of the energy storage battery liquid cooling unit system, and by monitoring the operating pressure ratio under the real-time operating parameters and real-time control parameters, an operating pressure ratio-parameter curve is established.

[0127] The highest operating pressure ratio and its corresponding first parameter, and the lowest operating pressure ratio and its corresponding second parameter are obtained from the operating pressure ratio-parameter curve. Based on the first parameter, the optimal parameter relationship between the first operating parameter and the first control parameter is determined. Based on the second parameter, the worst parameter relationship between the second operating parameter and the second control parameter is determined.

[0128] Determine the first operating pressure ratio difference and the second operating pressure ratio difference between the operating pressure ratio and the highest operating pressure and the lowest operating pressure ratio, respectively;

[0129] Based on the first operating pressure differential ratio, the adjustment range of the control parameters is determined. Based on the worst-case parameter relationship and the operating parameters of the operating pressure ratio, the adjustment weight of the control parameters is determined. Based on the adjustment range and the adjustment weight of the control parameters, the fine-tuning data of the control parameters to be adjusted is determined.

[0130] Based on the second operating pressure differential ratio and the optimal parameter relationship, the fine-tuning data is verified and corrected to determine whether the parameter relationship between the control parameters adjusted according to the fine-tuning data and the operating parameters of the operating pressure ratio is within a preset range from the optimal parameter relationship.

[0131] If so, fine-tune the control parameters to be adjusted according to the fine-tuning data;

[0132] Otherwise, the fine-tuning data is corrected based on the second operating differential pressure ratio.

[0133] In this embodiment, the operating pressure ratio-parameter curve is a graph showing the relationship between the operating pressure ratio, operating parameters, and control parameters.

[0134] In this embodiment, the larger the first operating pressure differential ratio, the smaller the corresponding parameter adjustment range.

[0135] In this embodiment, the greater the difference between the operating parameters and the worst-case parameter in the relationship between the operating pressure ratio and the operating parameters, the greater the corresponding parameter adjustment weight.

[0136] In this embodiment, the fine-tuning data of the control parameters to be adjusted are the adjustment of the opening degree of the electronic expansion valve 7 and the adjustment of the speed of the fan 10.

[0137] In this embodiment, the method of correcting the fine-tuning data based on the second operating differential pressure ratio is the opposite of the method of adjusting based on the first operating differential pressure ratio.

[0138] The beneficial effects of the above design scheme are as follows: by obtaining the highest operating pressure ratio and its corresponding first parameter, and the lowest operating pressure ratio and its corresponding second parameter from the operating pressure ratio-parameter curve, the optimal parameter relationship between the first operating parameter and the first control parameter is determined based on the first parameter, and the worst parameter relationship between the second operating parameter and the second control parameter is determined based on the second parameter. The first operating pressure ratio difference and the second operating pressure ratio difference between the operating pressure ratio and the highest and lowest operating pressure ratios are determined respectively. Based on the first operating pressure ratio difference and the second operating pressure ratio difference, the optimal parameter relationship and the worst parameter relationship, the operating pressure ratio to be adjusted is analyzed, and the adjustment parameters are determined. This ensures that the real-time operating pressure ratio is always kept within the preset range, significantly reducing compressor power consumption and improving operating energy efficiency.

[0139] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of this application and its equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for energy-saving control of ultra-low pressure ratio operation of a liquid-cooled energy storage battery unit, characterized in that, include: S1: Obtain the structural distribution of the energy storage battery liquid cooling unit system, and collect the operating parameters of the battery liquid cooling unit system from the structural distribution; S2: Based on the working parameters, the target value of the return gas pressure saturation temperature is calculated, and based on the relationship between the return gas pressure saturation temperature value and the target value of the return gas pressure saturation temperature, the control parameters of the electronic expansion valve (7) are determined. S3: Based on the operating parameters, calculate the target value of exhaust pressure saturation temperature, and based on the relationship between the exhaust pressure saturation temperature value and the target value of exhaust pressure saturation temperature, determine the control parameters for the fan (10); It also includes: obtaining the operating pressure ratio of the compressor (1) under the operation of the control parameters of the electronic expansion valve (7) and the control parameters of the fan (10); Based on the relationship between the operating pressure ratio and the preset operating pressure ratio, the control parameters are fine-tuned, specifically as follows: When the operating pressure ratio is less than or equal to the preset operating pressure ratio, the control parameters are not adjusted; When the operating pressure ratio is greater than the preset operating pressure ratio, the control parameters to be adjusted when the operating pressure ratio is greater than the preset operating pressure ratio are obtained. Based on the operating pressure ratio-parameter curve, the control parameters to be adjusted are fine-tuned, specifically as follows: Based on the real-time operating parameters and real-time control parameters of the energy storage battery liquid cooling unit system, and by monitoring the operating pressure ratio under the real-time operating parameters and real-time control parameters, an operating pressure ratio-parameter curve is established. The highest operating pressure ratio and its corresponding first parameter, and the lowest operating pressure ratio and its corresponding second parameter are obtained from the operating pressure ratio-parameter curve. Based on the first parameter, the optimal parameter relationship between the first operating parameter and the first control parameter is determined. Based on the second parameter, the worst parameter relationship between the second operating parameter and the second control parameter is determined. Determine the first operating pressure ratio difference and the second operating pressure ratio difference between the operating pressure ratio and the highest operating pressure ratio and the lowest operating pressure ratio, respectively; Based on the first operating pressure ratio difference, the adjustment range of the control parameters is determined. Based on the worst parameter relationship and the working parameters of the operating pressure ratio, the adjustment weight of the control parameters is determined. Based on the adjustment range and the adjustment weight of the control parameters, the fine-tuning data of the control parameters to be adjusted is determined. Based on the second operating pressure ratio difference and the optimal parameter relationship, the fine-tuning data is verified and corrected to determine whether the parameter relationship between the control parameters adjusted according to the fine-tuning data and the operating pressure ratio working parameters is within the preset range from the optimal parameter relationship. If so, fine-tune the control parameters to be adjusted according to the fine-tuning data; Otherwise, the fine-tuning data is corrected based on the second operating pressure ratio difference.

2. The energy-saving control method for ultra-low pressure ratio operation of a liquid-cooled energy storage battery unit according to claim 1, characterized in that, In S1, the structural distribution of the energy storage battery liquid cooling unit system is obtained, including a compressor (1), a liquid supply pipe is connected through the compressor (1), the other end of the liquid supply pipe is connected through the outer heat exchanger (9), an exhaust temperature sensor (12) and a high pressure sensor (11) are also provided on the liquid supply pipe, a fan (10) and an ambient temperature sensor (8) are provided on the outer heat exchanger (9), a connecting pipe is also connected through the outer heat exchanger (9), the other end of the connecting pipe is connected through the medium heat exchanger (6), an electronic expansion valve (7) is provided on the connecting pipe, a return liquid pipe is connected through the medium heat exchanger (6), the other end of the return liquid pipe is connected through the compressor (1), a low pressure sensor (2) and a return gas temperature sensor (3) are provided on the return liquid pipe, and a return liquid temperature sensor (4) and a liquid supply temperature sensor (5) are also provided on the medium heat exchanger (6).

3. The energy-saving control method for ultra-low pressure ratio operation of a liquid-cooled energy storage battery unit according to claim 2, characterized in that, In step S1, the operating parameters of the battery liquid cooling unit system are collected from the structural distribution, including: The return gas pressure of the energy storage battery liquid cooling unit system is collected from the low-pressure sensor (2), the exhaust pressure of the energy storage battery liquid cooling unit system is collected from the high-pressure sensor (11), the return liquid temperature is collected from the return liquid temperature sensor (4), the supply liquid temperature is collected from the supply liquid temperature sensor (5), the return gas pressure temperature value is collected from the return gas temperature sensor (3), the exhaust temperature value is collected from the exhaust temperature sensor (12), and the ambient temperature value is collected from the ambient temperature sensor (8).

4. The energy-saving control method for ultra-low pressure ratio operation of a liquid-cooled energy storage battery unit according to claim 1, characterized in that, In step S2, the target value of the return gas pressure saturation temperature is calculated based on the operating parameters, including: Based on the aforementioned operating parameters, the target value of the return gas pressure saturation temperature is calculated according to the following formula; Tes = To - x * △t1 / b K=Pd-Tc Where Tes represents the target value of the saturation temperature of the return gas pressure, To represents the value of the liquid supply temperature, K represents the exhaust superheat, Δt1 is 2~5, b is 10, Pd represents the exhaust temperature, and Tc represents the saturation temperature corresponding to the exhaust pressure. When compressor (1) is off, x returns to its default value. When compressor (1) is on, x is adjusted in real time according to the exhaust superheat, specifically: When the exhaust superheat is greater than c, x is reduced by 1 from the current real-time value in each adjustment cycle, and the corrected Tes value is not higher than the Tes value calculated by the default value of x plus 4℃. When c ≥ exhaust superheat ≥ c - Δt2, x remains unchanged at its current real-time value; When c-△t2>exhaust superheat, x is increased by 1 in each adjustment cycle to the current real-time value, and the corrected Tes value is not lower than the Tes value calculated by the default value of x minus 4℃; The value of △t2 must meet the reliability requirements in the compressor specification sheet, and at the same time, it should not leave too large a margin, so that Te can be kept at a high value as much as possible.

5. The energy-saving control method for ultra-low pressure ratio operation of a liquid-cooled energy storage battery unit according to claim 1, characterized in that, In step S3, the target value of the exhaust pressure saturation temperature is calculated based on the operating parameters, including: Based on the aforementioned operating parameters, the target value of the exhaust pressure saturation temperature is calculated using the following formula; Tcs = max(T1 + Δt3, y * Pes) Where Tcs represents the target value of exhaust pressure saturation temperature, T1 represents the ambient temperature value, Pes represents the target value of return gas pressure saturation temperature, the y value is taken according to the minimum pressure ratio allowed by the compressor specification, which is 1.1~1.3, and Δt3 is taken as 5~10; When compressor (1) is off, the y value returns to its default value. After compressor (1) is on, the y value is corrected according to the return gas pressure saturation temperature value Te. When Te < Tes-a, and the opening of the electronic expansion valve exceeds 70% of its maximum opening, the y value is increased by 0.1 based on the current real-time value for each adjustment cycle. The corrected y value should always be limited to the maximum correction value based on the default value. The corrected y value should not exceed 1.5~1.8, and a takes 0~2. When Tes≥Te≥Tes-a, the y value remains the current real-time value; When Te > Tes, the y value is reduced by 0.1 from the current real-time value in each adjustment cycle. The corrected y value is always not less than the default value and the corrected y value is ≥1.1.

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