Fuzzy control method for cooling capacity of liquid cooling unit, liquid cooling unit and energy storage system

Abstract

The present invention discloses a fuzzy control method for the cooling capacity of a liquid cooling unit, a liquid cooling unit and an energy storage system, and relates to the technical field of refrigeration equipment control methods, which includes taking the temperature control error e of the liquid cooling unit as an input quantity, and taking at least one controllable parameter of the liquid cooling unit as a control quantity, to establish a fuzzy control system; the fuzzy control system controls at least one controllable parameter in the liquid cooling unit according to the temperature control error e, so as to reduce the temperature control error e. The present invention mainly solves the problem that traditional automatic control theory is difficult to bring good control effects to liquid cooling units; compared with traditional temperature control systems, the present invention has the characteristics of short response time, small overshoot, high steady-state accuracy, rapid recovery to steady state when encountering interference, and good dynamic and static performance. At the same time, it also has strong adaptability to the inertial lag temperature link, thereby bringing better temperature control effects to the energy storage system.

Description

Technical Field

[0001] The present invention relates to the technical field of refrigeration equipment control methods, and in particular to a refrigeration capacity fuzzy control method for a liquid cooling unit, a liquid cooling unit and an energy storage system. Background Art

[0002] An energy storage system is a system used to store and release electrical energy. Its core components include battery packs / battery groups (collectively referred to as batteries). The batteries in the energy storage system will generate a large amount of heat during the charging and discharging process. If the heat cannot be discharged in time, the temperature of the energy storage system will increase, posing a safety hazard, and thus affecting the performance of the batteries and the normal operation of the energy storage system.

[0003] In order to reduce the temperature of the battery, it is usually necessary to configure a heat dissipation system in the energy storage system to dissipate heat from the battery. Among them, liquid cooling is the most widely used heat dissipation solution.

[0004] The liquid cooling unit is the actuator of the liquid cooling heat dissipation solution. The temperature control system with the liquid cooling unit as the core belongs to an automatic control system. In the prior art, a bidirectional thyristor power unit is generally used to control the cooling power of the liquid cooling unit. Combined with the automatic control algorithm, the temperature control system of the liquid cooling unit can be automatically adjusted.

[0005] However, the temperature control system of the liquid cooling unit has the characteristics of large inertia and hysteresis, and the energy storage system is unidirectional when heating up. Under the influence of the above factors, it is difficult to establish an accurate mathematical model in the temperature control system of the liquid cooling unit, that is, the traditional automatic control theory is difficult to bring good control effect for the liquid cooling unit. Summary of the invention

[0006] The object of the present invention is to provide a fuzzy control method for the cooling capacity of a liquid cooling unit, a liquid cooling unit and an energy storage system, which can bring about a better temperature control effect.

[0007] To achieve the above object, the present invention provides the following technical solution: a fuzzy control method for the cooling capacity of a liquid cooling unit, applied in the liquid cooling unit; the method comprises:

[0008] A fuzzy control system is established using the temperature control error e of the liquid cooling unit as an input quantity and at least one controllable parameter of the liquid cooling unit as a control quantity;

[0009] The fuzzy control system controls at least one controllable parameter in the liquid cooling unit according to the temperature control error e to reduce the temperature control error e.

[0010] A liquid cooling unit, which applies the above-mentioned refrigeration capacity fuzzy control method of the liquid cooling unit;

[0011] It includes a refrigeration module, a liquid cooling module and a heat exchanger;

[0012] The refrigeration module includes a compressor, a condenser with a fan, and an electronic expansion valve;

[0013] The liquid cooling module includes a water pump, a liquid cooling plate capable of exchanging heat with a heating element, and a heater for heating a liquid cooling medium;

[0014] The refrigerant channels of the compressor, the condenser, the electronic expansion valve and the heat exchanger are connected in sequence, so that the refrigerant can circulate among the refrigerant channels of the compressor, the condenser, the electronic expansion valve and the heat exchanger;

[0015] The water pump, the liquid cooling plate and the liquid cooling medium channels of the heat exchanger are connected in sequence, so that the liquid cooling medium can circulate among the water pump, the liquid cooling plate and the liquid cooling medium channels of the heat exchanger, and the heater is connected to one of the nodes of the liquid cooling module.

[0016] An energy storage system comprises the above-mentioned liquid cooling unit.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: the fuzzy control method for the cooling capacity of the liquid cooling unit, the liquid cooling unit and the energy storage system of the present invention, the fuzzy control system controls at least one controllable parameter in the liquid cooling unit according to the temperature control error e to reduce the temperature control error e; compared with the traditional temperature control system, the fuzzy control system has the characteristics of short response time, small overshoot, high steady-state accuracy, rapid recovery to steady state when encountering interference, and good dynamic and static performance. At the same time, the fuzzy control system has strong adaptability to the inertial lag temperature link, thereby bringing a better temperature control effect to the energy storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the system structure of the liquid cooling unit of the present invention.

[0019] Figure 2 It is a flow chart of the refrigeration capacity fuzzy control method of the liquid cooling unit of the present invention.

[0020] The accompanying drawings are marked as follows: 1. compressor; 2. condenser; 3. fan; 4. electronic expansion valve; 5. heat exchanger; 6. heater; 7. battery pack; 8. water pump; 9. liquid cooling plate. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] This embodiment provides a liquid cooling unit that can be used in, for example, energy storage systems, power generation systems, communications or server rooms to dissipate heat for heat sources such as batteries, generators and electronic equipment.

[0023] See also Figure 1 The liquid cooling unit of this embodiment includes a refrigeration module, a liquid cooling module and a heat exchanger 5.

[0024] Among them, the refrigeration module is based on refrigerant circulation and is used for refrigeration; the liquid cooling module is based on liquid cooling medium (such as pure water or formulated coolant) and is used to conduct heat from the heating element; the heat exchanger 5 is used for heat exchange between the refrigeration module and the liquid cooling module. In most cases, the heat exchanger 5 is a plate heat exchanger 5.

[0025] The refrigeration module includes a compressor 1, a condenser 2 with a fan 3, and an electronic expansion valve 4. The refrigerant channels of the compressor 1, the condenser 2, the electronic expansion valve 4, and the heat exchanger 5 (used to act as an evaporator of the refrigeration system) are connected in sequence, so that the refrigerant can circulate between the refrigerant channels of the compressor 1, the condenser 2, the electronic expansion valve 4, and the heat exchanger 5.

[0026] The liquid cooling module includes at least a water pump 8 and a liquid cooling plate 9 capable of exchanging heat with the heat source. The liquid cooling medium channels of the water pump 8, the liquid cooling plate 9 and the heat exchanger 5 are connected in sequence, so that the liquid cooling medium can circulate among the water pump 8, the liquid cooling plate 9 and the liquid cooling medium channels of the heat exchanger 5.

[0027] Furthermore, the liquid cooling module also includes a heater 6 for heating the liquid cooling medium. In this embodiment, the heater 6 is connected between the liquid cooling medium channel of the heat exchanger 5 and the liquid cooling plate 9 .

[0028] When the water pump 8 is running, the liquid cooling medium is driven to circulate between the water pump 8, the liquid cooling plate 9 and the liquid cooling medium channels of the heat exchanger 5. When the liquid cooling medium flows through the liquid cooling plate 9, it can absorb the heat of the heating element (the battery pack 7 of the energy storage system in this embodiment) and transfer the heat to the heat exchanger 5; when the compressor 1 is running, the refrigerant is driven to circulate between the compressor 1, the condenser 2, the electronic expansion valve 4 and the refrigerant channels of the heat exchanger 5. When the condensation passes through the heat exchanger 5, the heat exchanger 5 acts as an evaporator of the refrigeration system, which can quickly cool the liquid cooling medium in the heat exchanger 5. The cooled liquid cooling medium is circulated again and connected to the liquid cooling plate 9 to absorb the heat of the heating element again, thereby achieving the effect of quickly cooling the heating element; in the above process, the heater 6 is used to heat the liquid cooling medium at extremely low temperatures to prevent the liquid cooling medium from solidifying and damaging the liquid cooling module and the heat exchanger 5.

[0029] This embodiment also provides a fuzzy control method for the cooling capacity of a liquid cooling unit, which is applied to the above-mentioned liquid cooling unit to control the cooling capacity of the liquid cooling unit.

[0030] See also Figure 2 The refrigeration capacity fuzzy control method of the liquid cooling unit of this embodiment includes:

[0031] A fuzzy control system is established by taking the temperature control error e of the liquid cooling unit as an input quantity and taking at least one controllable parameter of the liquid cooling unit as a control quantity;

[0032] The fuzzy control system controls at least one controllable parameter in the liquid cooling unit according to the temperature control error e to reduce the temperature control error e.

[0033] The liquid cooling unit involved in this embodiment, in its automatic control system, will use the temperature of the liquid cooling medium as the control object, and the power of the compressor 1 in its refrigeration module, the opening of the electronic expansion valve 4 and the speed of the water pump 8 in its liquid cooling module can all be adjusted as controllable parameters of the automatic control system. The control goal is to make the actual temperature T of the liquid cooling medium in the liquid cooling unit as close to the target temperature T0 as possible, so as to minimize the temperature control error e. At this time, the liquid cooling medium is close to a constant temperature, and has a better heat dissipation effect on heat sources such as batteries, generators and electronic equipment.

[0034] Specifically, the temperature control error e of the liquid cooling unit is: e = ΔT = T0 - T;

[0035] Wherein, T0 is the target temperature of the liquid cooling medium in the liquid cooling unit, and T is the actual temperature of the liquid cooling medium in the liquid cooling unit.

[0036] It should be noted that in the physical quantity domain, the target temperature T0, the actual temperature T and the temperature control error e can be expressed in units of temperature such as Celsius or Fahrenheit. In the fuzzy domain, the target temperature T0, the actual temperature T and the temperature control error e are all expressed as a set of fuzzy domains.

[0037] Specifically, the controllable parameter of the liquid cooling unit is the opening u of the electronic expansion valve 4 .

[0038] Increasing the opening u of the electronic expansion valve 4 can increase the flow rate of the refrigerant in the refrigeration module, thereby improving the refrigeration effect of the heat exchanger 5, so as to absorb more heat in the liquid-cooling medium and reduce the actual temperature T of the liquid-cooling medium; reducing the opening u of the electronic expansion valve 4 can reduce the flow rate of the refrigerant in the refrigeration module, thereby reducing the refrigeration effect of the heat exchanger 5, so as to absorb less heat in the liquid-cooling medium and increase the actual temperature T of the liquid-cooling medium.

[0039] This embodiment explores how to use the temperature control error e of the liquid cooling unit as the input of the fuzzy control system to control the opening u of the electronic expansion valve 4, so that the actual temperature T of the liquid cooling medium in the liquid cooling unit is as close as possible to the target temperature T0, thereby minimizing the temperature control error e.

[0040] Specifically, the specific method of establishing a fuzzy control system includes:

[0041] The input quantity of the fuzzy control system is determined to be: the temperature control error e of the liquid cooling unit, and the control quantity of the fuzzy control system is determined to be: the opening u of the electronic expansion valve 4;

[0042] Convert the temperature control error e into the first fuzzy domain, divide the temperature control error e into the first fuzzy subset, and define the membership function of the first fuzzy domain and the first fuzzy subset;

[0043] The rate of change of the temperature control error e is E c Converted to the second fuzzy domain, it is the rate of change E of the temperature control error e c Divide the second fuzzy subset, define the second fuzzy domain and the membership function of the second fuzzy subset;

[0044] Convert the opening u of the electronic expansion valve 4 into a third fuzzy domain U, divide the opening u of the electronic expansion valve 4 into a third fuzzy subset, and define a membership function of the third fuzzy domain and the third fuzzy subset;

[0045] Establish the temperature control error e and the rate of change of the temperature control error e E c and the fuzzy control rule of the opening u of the electronic expansion valve 4;

[0046] Obtain the fuzzy relationship R between the temperature control error e and the opening u of the electronic expansion valve 4 in the fuzzy domain;

[0047] Obtain the output of the control quantity of the fuzzy control system in the fuzzy domain;

[0048] Defuzzify the output of the fuzzy control system to obtain the physical quantity output of the fuzzy control system.

[0049] Specifically, the temperature control error, e, is:

[0050] The first fuzzy domain is (-3, -2, -1, 0, +1, +2, +3), and the first fuzzy subsets are NB (negative large), NM (negative medium), NS (negative small), O (zero), PS (positive small), PM (positive medium) and PB (positive large);

[0051] The membership function of the first fuzzy universe and the first fuzzy subset is:

[0052] When the temperature control error e = -3, the membership degrees for NB, NM, NS, O, PS, PM and PB are 1, 0.5, 0.3, 0, 0, 0, 0, respectively;

[0053] When the temperature control error e = -2, the membership degrees for NB, NM, NS, O, PS, PM and PB are 0.5, 1, 0.5, 0.2, 0, 0, 0 respectively;

[0054] When the temperature control error e = -1, the membership degrees for NB, NM, NS, O, PS, PM and PB are 0.3, 0.5, 1, 0.5, 0.2, 0, 0 respectively;

[0055] When the temperature control error e = 0, the membership degrees for NB, NM, NS, O, PS, PM, and PB are 0.1, 0.2, 0.5, 1, 0.5, 0.2, and 0.1, respectively;

[0056] When the temperature control error e = 1, the membership degrees for NB, NM, NS, O, PS, PM, and PB are 0, 0, 2, 0.5, 1, 0.5, and 0.3, respectively;

[0057] When the temperature control error e = 2, the membership degrees for NB, NM, NS, O, PS, PM, and PB are 0, 0, 0, 0.2, 0.5, 1, and 0.5, respectively;

[0058] When the temperature control error e=3, the membership degrees of NB, NM, NS, O, PS, PM and PB are 0, 0, 0, 0, 0.3, 0.5 and 1 respectively;

[0059] The rate of change of temperature control error e c ,have:

[0060] The second fuzzy domain is (-3, -2, -1, 0, +1, +2, +3), and the second fuzzy subsets are NB (negative large), NM (negative medium), NS (negative small), O (zero), PS (positive small), PM (positive medium) and PB (positive large);

[0061] The membership function of the second fuzzy universe and the second fuzzy subset is:

[0062] The rate of change of temperature control error e c = -3, the membership degrees to NB, NM, NS, O, PS, PM and PB are 1, 0.5, 0.3, 0, 0, 0, 0, respectively;

[0063] The rate of change of temperature control error e c = -2, the membership degrees to NB, NM, NS, O, PS, PM and PB are 0.5, 1, 0.5, 0.2, 0, 0, 0 respectively;

[0064] The rate of change of temperature control error e c = -1, the membership degrees to NB, NM, NS, O, PS, PM and PB are 0.3, 0.5, 1, 0.5, 0.2, 0, 0 respectively;

[0065] The rate of change of temperature control error e c =0, the membership degrees to NB, NM, NS, O, PS, PM and PB are 0.1, 0.2, 0.5, 1, 0.5, 0.2 and 0.1 respectively;

[0066] The rate of change of temperature control error e c =1, the membership degrees to NB, NM, NS, O, PS, PM and PB are 0, 0, 2, 0.5, 1, 0.5 and 0.3 respectively;

[0067] The rate of change of temperature control error e c =2, the membership degrees of NB, NM, NS, O, PS, PM and PB are 0, 0, 0, 0.2, 0.5, 1, 0.5 respectively;

[0068] The rate of change of temperature control error e c When =3, the membership degrees of NB, NM, NS, O, PS, PM and PB are 0, 0, 0, 0, 0.3, 0.5 and 1 respectively;

[0069] The opening u of the electronic expansion valve 4 is:

[0070] The third fuzzy domain U is (-3, -2, -1, 0, +1, +2, +3), and the third fuzzy subsets are NB (negative large), NM (negative medium), NS (negative small), O (zero), PS (positive small), PM (positive medium) and PB (positive large);

[0071] The membership function of the third fuzzy universe U and the third fuzzy subset is:

[0072] When the opening degree U of the electronic expansion valve 4 is -3, the membership degrees of NB, NM, NS, O, PS, PM and PB are 1, 0.5, 0.3, 0, 0, 0, 0, respectively;

[0073] When the opening degree U of the electronic expansion valve 4 is -2, the membership degrees of NB, NM, NS, O, PS, PM and PB are 0.5, 1, 0.5, 0.2, 0, 0, 0 respectively;

[0074] When the opening degree U of the electronic expansion valve 4 is -1, the membership degrees to NB, NM, NS, O, PS, PM and PB are 0.3, 0.5, 1, 0.5, 0.2, 0, 0 respectively;

[0075] When the opening degree U of the electronic expansion valve 4 is 0, the membership degrees to NB, NM, NS, O, PS, PM and PB are 0.1, 0.2, 0.5, 1, 0.5, 0.2 and 0.1 respectively;

[0076] When the opening degree U of the electronic expansion valve 4 is 1, the membership degrees to NB, NM, NS, O, PS, PM and PB are 0, 0, 2, 0.5, 1, 0.5 and 0.3 respectively;

[0077] When the opening degree U of the electronic expansion valve 4 is 2, the membership degrees of NB, NM, NS, O, PS, PM and PB are 0, 0, 0, 0.2, 0.5, 1 and 0.5 respectively;

[0078] When the opening degree U of the electronic expansion valve 4 is 3, the degrees of membership to NB, NM, NS, O, PS, PM and PB are 0, 0, 0, 0, 0.3, 0.5 and 1 respectively.

[0079] The membership function of the first fuzzy domain and the first fuzzy subset, the membership function of the second fuzzy domain and the second fuzzy subset, and the membership function of the third fuzzy domain and the third fuzzy subset can also be expressed as the following table:

[0080]

[0081] Table 1 The membership function of the first fuzzy domain and the first fuzzy subset, the membership function of the second fuzzy domain and the second fuzzy subset, and the membership function of the third fuzzy domain and the third fuzzy subset.

[0082] For the temperature control error e, the actual physical quantity has a mapping relationship with the first fuzzy domain (-3, -2, -1, 0, +1, +2, +3), and the mapping relationship is an engineering calibration relationship; similarly, for the opening u of the electronic expansion valve 4, the actual physical quantity (%) has a mapping relationship with the third fuzzy domain U (-3, -2, -1, 0, +1, +2, +3), and the mapping relationship is also an engineering calibration relationship.

[0083] Specifically, the temperature control error e and the rate of change of the temperature control error e are c And the fuzzy control rule of the opening u of the electronic expansion valve 4 is:

[0084] if e is NB and Ec is PB, then U is 0;

[0085] if e is NB and Ec is PM, then U is PS;

[0086] if e is NB and Ec is PS, then U is PM;

[0087] if e is NB and Ec is 0, then U is PB;

[0088] if e is NB and Ec is NS, then U is PB;

[0089] if e is NB and Ec is NM, then U is PB;

[0090] if e is NB and Ec is NB, then U is PB;

[0091] if e is NM and Ec is PB, then U is 0;

[0092] if e is NM and Ec is PM, then U is 0;

[0093] if e is NM and Ec is PS, then U is PS;

[0094] if e is NM and Ec is 0, then U is PM;

[0095] if e is NM and Ec is NS, then U is PM;

[0096] if e is NM and Ec is NM,then U is PB;

[0097] if e is NM and Ec is NB,then U is PB;

[0098] if e is NS and Ec is PB,then U is NS;

[0099] if e is NS and Ec is PM,then U is 0;

[0100] if e is NS and Ec is PS,then U is 0;

[0101] if e is NS and Ec is 0,then U is PS;

[0102] if e is NS and Ec is NS,then U is PM;

[0103] if e is NS and Ec is NM,then U is PM;

[0104] if e is NS and Ec is NB,then U is PB;

[0105] if e is 0 and Ec is PB,then U is NM;

[0106] if e is 0 and Ec is PM,then U is NS;

[0107] if e is 0 and Ec is PS,then U is NS;

[0108] if e is 0 and Ec is 0,then U is 0;

[0109] if e is 0 and Ec is NS,then U is PS;

[0110] if e is 0 and Ec is NM,then U is PS;

[0111] if e is 0 and Ec is NB,then U is PM;

[0112] if e is PS and Ec is PB,then U is NB;

[0113] if e is PS and Ec is PM,then U is NM;

[0114] if e is PS and Ec is PS,then U is NM;

[0115] if e is PS and Ec is 0,then U is NS;

[0116] if e is PS and Ec is NS,then U is 0;

[0117] if e is PS and Ec is NM,then U is 0;

[0118] if e is PS and Ec is NB,then U is PS;

[0119] if e is PM and Ec is PB,then U is NB;

[0120] if e is PM and Ec is PM,then U is NB;

[0121] if e is PM and Ec is PS,then U is NM;

[0122] if e is PM and Ec is 0,then U is NM;

[0123] if e is PM and Ec is NS,then U is NS;

[0124] if e is PM and Ec is NM,then U is 0;

[0125] if e is PM and Ec is NB,then U is 0;

[0126] if e is PB and Ec is PB,then U is NB;

[0127] if e is PB and Ec is PM,then U is NB;

[0128] if e is PB and Ec is PS, then U is NB;

[0129] if e is PB and Ec is 0, then U is NB;

[0130] if e is PB and Ec is NS, then U is NM;

[0131] if e is PB and Ec is NM, then U is NS;

[0132] if e is PB and Ec is NB, then U is 0.

[0133] The fuzzy control rules are actually the mathematical expression of engineering calibration experience or life experience in the fuzzy domain. The above fuzzy control rules express "if e is negative and large, then U is negative and large", "if e is negative and neutral, then U is negative and neutral", "if e is negative and small, then U is negative and small", "if e is 0, then U is 0", "if e is positive and small, then U is positive and small", "if e is positive and neutral, then U is positive and neutral", and "if e is positive and large, then U is positive and large".

[0134] The above fuzzy control rules can also be expressed as the following table:

[0135]

[0136] Table 2 Temperature control error e, change rate E of temperature control error e c And the fuzzy control rule of the opening u of the electronic expansion valve 4.

[0137] The fuzzy control rule is a collection of multiple statements, which can be expressed as a fuzzy subset on U×e, that is, a fuzzy relationship R. Combined with the above fuzzy control rules, the fuzzy relationship R between the temperature control error e and the opening u of the electronic expansion valve 4 in the fuzzy domain is specifically:

[0138] R=(NBe×NBu)∪(NMe×NMu)∪(NSe×NSu)∪(Z0e×Z0u)∪(PBe×PBu)∪(PMe×PMu)∪(PSe×PSu).

[0139] Specifically, the output of the control quantity of the fuzzy control system in the fuzzy domain is: U = e·R.

[0140] Finally, the output U=e·R of the control quantity of the fuzzy control system in the fuzzy domain is defuzzified (inverse fuzzification) to obtain the physical quantity output of the fuzzy control system, that is, the actual physical quantity (%) of the opening u of the electronic expansion valve 4.

[0141] In a real case, when the temperature control error e is negative, the actual temperature T of the liquid cooling medium in the liquid cooling unit is much greater than the target temperature T0. In the fuzzy domain, the temperature control error e = NB, and the output of the fuzzy control system is a fuzzy vector, which can be expressed as:

[0142]

[0143] According to the "maximum membership principle", the fuzzy vector is defuzzified, and the opening u=3 of the electronic expansion valve 4 is selected, that is, the opening of the electronic expansion valve 4 should be increased to increase the circulation of the refrigerant in the refrigeration module, thereby improving the refrigeration effect of the heat exchanger 5 to absorb more heat in the liquid cooling medium and reduce the actual temperature T of the liquid cooling medium.

[0144] This embodiment also provides an energy storage system, which includes the above-mentioned liquid cooling unit.

[0145] The fuzzy control method for the cooling capacity of the liquid cooling unit, the liquid cooling unit and the energy storage system of this embodiment, the fuzzy control system controls at least one controllable parameter in the liquid cooling unit according to the temperature control error e to reduce the temperature control error e; compared with the traditional temperature control system, the fuzzy control system has the characteristics of short response time, small overshoot, high steady-state accuracy, rapid recovery to steady state when encountering interference, and good dynamic and static performance. At the same time, it has strong adaptability to the inertial lag temperature link, thereby bringing a better temperature control effect to the energy storage system.

[0146] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A fuzzy control method for the cooling capacity of a liquid cooling unit, applied in the liquid cooling unit; characterized in that: The liquid cooling unit includes a refrigeration module, a liquid cooling module and a heat exchanger; The refrigeration module includes a compressor, a condenser with a fan, and an electronic expansion valve; The liquid cooling module includes a water pump, a liquid cooling plate capable of exchanging heat with a heating element, and a heater for heating a liquid cooling medium; The refrigerant channels of the compressor, the condenser, the electronic expansion valve and the heat exchanger are connected in sequence, so that the refrigerant can circulate among the refrigerant channels of the compressor, the condenser, the electronic expansion valve and the heat exchanger; The water pump, the liquid cooling plate and the liquid cooling medium channels of the heat exchanger are connected in sequence, so that the liquid cooling medium can circulate among the water pump, the liquid cooling plate and the liquid cooling medium channels of the heat exchanger, and the heater is connected to one of the nodes of the liquid cooling module; The method includes: The temperature control error of the liquid cooling unit is as input quantity, and taking at least one controllable parameter of the liquid cooling unit as control quantity, a fuzzy control system is established; The fuzzy control system controls the error according to the temperature , controlling at least one controllable parameter in the liquid cooling unit to reduce the temperature control error ; The controllable parameter of the liquid cooling unit is the opening of the electronic expansion valve. ; The specific method for establishing the fuzzy control system includes: Determine the input quantity of the fuzzy control system as follows: the temperature control error of the liquid cooling unit , and determine the control quantity of the fuzzy control system as: the opening of the electronic expansion valve ; The temperature control error Converted into the first fuzzy domain, the temperature control error Dividing the first fuzzy subset, and defining the first fuzzy domain and the membership function of the first fuzzy subset; The temperature control error Rate of change Converted into the second fuzzy domain, the temperature control error Rate of change Dividing the second fuzzy subsets, and defining the second fuzzy domain and the membership function of the second fuzzy subsets; The opening degree of the electronic expansion valve Convert to the third fuzzy domain , is the opening degree of the electronic expansion valve Dividing a third fuzzy subset, and defining the third fuzzy domain and the membership function of the third fuzzy subset; Establishing the temperature control error , the temperature control error Rate of change and the opening degree of the electronic expansion valve Fuzzy control rules; Obtain the temperature control error The opening degree of the electronic expansion valve Fuzzy Relations in Fuzzy Domains ; Obtaining the output of the control variable of the fuzzy control system in the fuzzy domain; Defuzzifying the output of the fuzzy control system, that is, obtaining the physical quantity output of the fuzzy control system; The temperature control error ,have: The first fuzzy domain is (-3, -2, -1, 0, +1, +2, +3), and the first fuzzy subsets are NB (negative large), NM (negative medium), NS (negative small), O (zero), PS (positive small), PM (positive medium) and PB (positive large); The membership function of the first fuzzy universe and the first fuzzy subset is: The temperature control error When , the membership degrees to NB, NM, NS, O, PS, PM and PB are 1, 0.5, 0.3, 0, 0, 0, 0 respectively; The temperature control error When , the membership degrees to NB, NM, NS, O, PS, PM and PB are 0.5, 1, 0.5, 0.2, 0, 0, 0 respectively; The temperature control error When , the membership degrees to NB, NM, NS, O, PS, PM and PB are 0.3, 0.5, 1, 0.5, 0.2, 0, 0 respectively; The temperature control error When , the membership degrees to NB, NM, NS, O, PS, PM and PB are 0.1, 0.2, 0.5, 1, 0.5, 0.2 and 0.1 respectively; The temperature control error When , the membership degrees to NB, NM, NS, O, PS, PM and PB are 0, 0, 2, 0.5, 1, 0.5 and 0.3 respectively; The temperature control error When , the membership degrees to NB, NM, NS, O, PS, PM and PB are 0, 0, 0, 0.2, 0.5, 1, 0.5 respectively; The temperature control error When , the membership degrees to NB, NM, NS, O, PS, PM and PB are 0, 0, 0, 0, 0.3, 0.5 and 1 respectively; The temperature control error Rate of change ,have: The second fuzzy domain is (-3, -2, -1, 0, +1, +2, +3), and the second fuzzy subsets are NB (negative large), NM (negative medium), NS (negative small), O (zero), PS (positive small), PM (positive medium) and PB (positive large); The membership function of the second fuzzy universe and the second fuzzy subset is: The temperature control error Rate of change When , the membership degrees to NB, NM, NS, O, PS, PM and PB are 1, 0.5, 0.3, 0, 0, 0, 0 respectively; The temperature control error Rate of change When , the membership degrees to NB, NM, NS, O, PS, PM and PB are 0.5, 1, 0.5, 0.2, 0, 0, 0 respectively; The temperature control error Rate of change When , the membership degrees to NB, NM, NS, O, PS, PM and PB are 0.3, 0.5, 1, 0.5, 0.2, 0, 0 respectively; The temperature control error Rate of change When , the membership degrees to NB, NM, NS, O, PS, PM and PB are 0.1, 0.2, 0.5, 1, 0.5, 0.2 and 0.1 respectively; The temperature control error Rate of change When , the membership degrees to NB, NM, NS, O, PS, PM and PB are 0, 0, 2, 0.5, 1, 0.5 and 0.3 respectively; The temperature control error Rate of change When , the membership degrees to NB, NM, NS, O, PS, PM and PB are 0, 0, 0, 0.2, 0.5, 1, 0.5 respectively; The temperature control error Rate of change When , the membership degrees to NB, NM, NS, O, PS, PM and PB are 0, 0, 0, 0, 0.3, 0.5 and 1 respectively; The opening degree of the electronic expansion valve ,have: The third fuzzy domain is (-3, -2, -1, 0, +1, +2, +3), the third fuzzy subset is NB (negative large), NM (negative medium), NS (negative small), O (zero), PS (positive small), PM (positive medium) and PB (positive large); The third fuzzy domain And the membership function of the third fuzzy subset is: Opening degree of electronic expansion valve When , the membership degrees to NB, NM, NS, O, PS, PM and PB are 1, 0.5, 0.3, 0, 0, 0, 0 respectively; Opening degree of electronic expansion valve When , the membership degrees to NB, NM, NS, O, PS, PM and PB are 0.5, 1, 0.5, 0.2, 0, 0, 0 respectively; Opening degree of electronic expansion valve When , the membership degrees to NB, NM, NS, O, PS, PM and PB are 0.3, 0.5, 1, 0.5, 0.2, 0, 0 respectively; Opening degree of electronic expansion valve When , the membership degrees to NB, NM, NS, O, PS, PM and PB are 0.1, 0.2, 0.5, 1, 0.5, 0.2 and 0.1 respectively; Opening degree of electronic expansion valve When , the membership degrees to NB, NM, NS, O, PS, PM and PB are 0, 0, 2, 0.5, 1, 0.5 and 0.3 respectively; Opening degree of electronic expansion valve When , the membership degrees to NB, NM, NS, O, PS, PM and PB are 0, 0, 0, 0.2, 0.5, 1, 0.5 respectively; Opening degree of electronic expansion valve When , the membership degrees to NB, NM, NS, O, PS, PM and PB are 0, 0, 0, 0, 0.3, 0.5 and 1 respectively; The temperature control error The opening degree of the electronic expansion valve Fuzzy Relations in Fuzzy Domains , specifically: 。 2. The refrigeration capacity fuzzy control method of a liquid cooling unit according to claim 1, characterized in that: The temperature control error of the liquid cooling unit , specifically: ; in, is the target temperature of the liquid cooling medium in the liquid cooling unit, is the actual temperature of the liquid cooling medium in the liquid cooling unit.

3. The refrigeration capacity fuzzy control method of a liquid cooling unit according to claim 1, characterized in that: The output of the control quantity of the fuzzy control system in the fuzzy domain is: .

4. An energy storage system, characterized in that: A liquid cooling unit comprising the method for fuzzy control of the cooling capacity of the liquid cooling unit according to any one of claims 1 to 3.

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