CN117638322A - Control method of energy storage thermal management system of centrifugal compressor - Google Patents

Abstract

The invention relates to the technical field of energy storage heat management. The control method of the energy storage heat management system of the centrifugal compressor comprises the following steps: performing start control, target frequency correction and stop control on the centrifugal compressor; the main throttling element is self-learned, and the opening degree of the main throttling element is controlled according to the suction superheat degree of the centrifugal compressor; the method comprises the steps of performing starting control, normal control and protection control on a cooling fan; starting control and rotating speed control are carried out on the water pump; the air supplementing control is carried out through a centrifugal compressor and an auxiliary throttling element; and performing system control based on surge characteristics of the centrifugal compressor. The method can effectively ensure the stability of the system and enable the system to operate efficiently.

Description

Control method of energy storage thermal management system of centrifugal compressor

Technical Field

The present invention relates generally to the field of energy storage thermal management. In particular, the invention relates to a control method of a centrifugal compressor energy storage thermal management system.

Background

Thermal management is the only requirement for electrochemical energy storage, and has significant effects on the performance, life and safety of the energy storage system. The liquid cooling and heating management system has strong heat exchange capability, the temperature difference of the battery core can be ensured to be within 3 ℃ by using the liquid cooling and heating management system, and the service life of the energy storage system can be obviously prolonged relative to the air cooling and heating management system.

The refrigerating capacity required by the existing energy-storage liquid cooling thermal management system is usually 100kW or less, and the compressor adopted by the refrigeration cycle with small refrigerating capacity is mainly a scroll compressor. The scroll compressor requires oil circulation, which reduces the reliability of the compressor and the liquid cooling thermal management system; the bearings of the scroll compressor are usually contact ball bearings, which are easy to wear, and the service life of the bearings is usually the bottleneck of the service life of the liquid cooling heat management system; the scroll compressor has larger volume and mass, is not beneficial to the energy density improvement of the energy storage system, and particularly has the disadvantages that the refrigeration capacity requirement is obviously increased along with the increase of the power density of the energy storage system and the scroll compressor is more obvious.

Disclosure of Invention

In order to at least partially solve the above-mentioned problems in the prior art, the present invention provides a control method of a centrifugal compressor energy storage thermal management system, comprising:

performing start control, target frequency correction and stop control on the centrifugal compressor;

the main throttling element is self-learned, and the opening degree of the main throttling element is controlled according to the suction superheat degree of the centrifugal compressor;

the method comprises the steps of performing starting control, normal control and protection control on a cooling fan;

starting control and rotating speed control are carried out on the water pump;

The air supplementing control is carried out through a centrifugal compressor and an auxiliary throttling element; and

the system control is based on the surge characteristics of the centrifugal compressor.

In one embodiment of the invention, it is provided that the start-up control of the centrifugal compressor comprises:

when the energy storage heat management system of the centrifugal compressor is electrified, each component of the energy storage heat management system of the centrifugal compressor is self-learned, and the energy storage heat management system of the centrifugal compressor is started when in a refrigeration mode and has refrigeration requirements; or when the energy storage heat management system of the centrifugal compressor receives a refrigeration request sent by the battery management system, starting the centrifugal compressor; and/or

Checking the high-low pressure difference of the centrifugal compressor when the centrifugal compressor is started, and opening a pressure relief valve to carry out bypass pressure relief when the high-low pressure difference is larger than a safety value, wherein the pressure relief valve is closed when the high-low pressure difference is smaller than the safety value or the pressure relief time exceeds a threshold time; and/or

Determining the starting platform frequency of the centrifugal compressor according to the refrigerating request grade sent by the battery management system or according to the water outlet temperature of the energy storage thermal management system of the centrifugal compressor; and/or

If the refrigeration demand increases during the start-up of the centrifugal compressor, the centrifugal compressor is still started according to the initial refrigeration demand and is reloaded to the load frequency after the start-up process is completed; if the refrigeration requirement becomes zero in the starting process of the centrifugal compressor, closing the energy storage heat management system of the centrifugal compressor; and if the refrigeration requirement becomes zero after the start-up process of the centrifugal compressor is finished, operating the centrifugal compressor until the shortest operation period is satisfied, and then closing the centrifugal compressor.

In one embodiment of the invention, providing for target frequency correction for a centrifugal compressor includes:

when the centrifugal compressor energy storage heat management system is in a refrigeration mode, the frequency output of the centrifugal compressor is corrected according to the suction pressure of the centrifugal compressor, wherein the frequency output of the centrifugal compressor is corrected through P8D control so as to ensure that the water outlet temperature of the centrifugal compressor energy storage heat management system is stable within a target temperature range.

In one embodiment of the invention, it is provided that the shutdown control of the centrifugal compressor comprises:

at normal shutdown, closing the centrifugal compressor, wherein a pressure release valve is opened to balance the pressure of the inlet side and the outlet side of the centrifugal compressor when the centrifugal compressor is closed, and closing the water pump and the cooling fan after the centrifugal compressor is closed, adjusting the opening degrees of the main throttle element and the auxiliary throttle element to 50%, and closing the pressure release valve, wherein the centrifugal compressor is closed after the centrifugal compressor is operated to meet the shortest operation period; and/or

At the time of the malfunction stop, the centrifugal compressor is turned off when the centrifugal compressor receives the malfunction signal, wherein the relief valve is opened to balance the pressure of the inlet side and the outlet side of the centrifugal compressor when the centrifugal compressor is turned off, and the water pump and the cooling fan are turned off after the centrifugal compressor is turned off, the opening degrees of the main throttle element and the auxiliary throttle element are adjusted to 50%, and the relief valve is turned off.

In one embodiment of the invention, it is provided that the main throttling element comprises an electric electronic expansion valve or an electromagnetic electronic expansion valve, the total number of steps of the electric electronic expansion valve or the electromagnetic electronic expansion valve being 500 steps, causing the main throttling element to perform self-learning comprises:

when the centrifugal compressor energy storage heat management system is electrified, the electric electronic expansion valve is enabled to move 500 steps to the minimum position or the electromagnetic electronic expansion valve is enabled to move 500 steps to the maximum position, and when self-learning reset is carried out, self-learning completion is determined through driving feedback of a self-learning completion signal; or alternatively

After the energy storage heat management system of the centrifugal compressor is powered on, the centrifugal compressor is stopped for the tenth time and no refrigeration requirement exists, the electric electronic expansion valve is made to move 500 steps to the minimum position or the electromagnetic electronic expansion valve is made to move 500 steps to the minimum position, and when the position of the main throttling element is smaller than 5 and the running time of 500 steps is longer than 16s, the self-learning is determined to be completed.

In one embodiment of the invention, it is provided that controlling the opening of the main throttling element in accordance with the suction superheat of the centrifugal compressor comprises:

setting target suction superheat degree, measuring the suction superheat degree of the current centrifugal compressor, and determining the opening degree of a main throttling element according to the target suction superheat degree and the suction superheat degree of the current centrifugal compressor, wherein the opening degree interval of the main throttling element is determined according to the opening degree range of the main throttling element, and the target suction superheat degree is determined according to the water inlet temperature of an energy storage heat management system of the centrifugal compressor.

In one embodiment of the invention, it is provided that the control of the start of the cooling fan comprises controlling an initial rotational speed of the cooling fan and a relation between the initial rotational speed and an outdoor ambient temperature; the general control of the cooling fan comprises adjusting the rotation speed of the cooling fan according to the control pressure during the operation of the centrifugal compressor energy storage heat management system; and the cooling fan performs protection control, including adjusting the rotation speed of the cooling fan to inhibit the occurrence of a severe condition when the characteristic of the centrifugal compressor energy storage heat management system touches a boundary value; and/or

The control of the starting of the water pump comprises the control of the starting rotating speed and the frequency raising speed of the water pump when the water pump is started so as to inhibit the water hammer effect: and determining the target rotating speed of the water pump according to the heat exchange of the battery and the water inlet and outlet temperature difference of the battery.

In one embodiment of the invention, provision is made for the control of the make-up air by means of the centrifugal compressor and the auxiliary throttle element to comprise:

determining the exhaust superheat degree and the suction superheat degree of the centrifugal compressor; and

and adjusting the auxiliary throttling element according to the exhaust superheat degree and the suction superheat degree.

In one embodiment of the invention, providing for system control based on surge characteristics of a centrifugal compressor includes:

Detecting the pressure ratio/flow of the compressor to obtain a current running state point, judging whether the current running state point reaches a surge protection area or not according to the current running state point, judging whether the gear of the fan is in an intervention state or not if the gear of the fan is in the intervention state, and otherwise, continuously detecting the pressure ratio/flow of the compressor to obtain the current running state point;

when judging whether the gear of the fan is in an interference state, if so, judging whether the opening of the main throttling element is in interference regulation; otherwise, adjusting the gear of the fan according to the surge curve;

judging whether the opening of the main throttling element is interfered and regulated or not, if yes, judging whether the auxiliary throttling element is interfered and regulated or not, otherwise, regulating the main throttling element according to a surge curve;

judging whether the auxiliary throttling element intervenes in control to intervene in adjustment or not when judging whether the auxiliary throttling element intervenes in control to intervene in adjustment, if so, judging whether a bypass valve is opened or not, otherwise, adjusting the auxiliary throttling element according to a surge curve;

judging whether the current running state point reaches a surge alarm point or not if the bypass valve is judged to be opened or not, otherwise, opening the bypass valve and adjusting; and

and when judging whether the current running state point reaches the surge alarm point, if so, stopping the compressor for alarm, otherwise, returning to detect the pressure ratio/flow of the compressor to obtain the current running state point.

The invention also proposes a centrifugal compressor energy storage thermal management system having a controller configured to perform the method.

The invention has at least the following beneficial effects: the invention provides a control method, an air supplementing method and a surge prevention method for each component of the system aiming at the energy storage heat management system of the centrifugal compressor, which can effectively ensure the stability of the system and ensure the system to operate efficiently.

Drawings

To further clarify the advantages and features present in various embodiments of the present invention, a more particular description of various embodiments of the present invention will be rendered by reference to the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. In the drawings, for clarity, the same or corresponding parts will be designated by the same or similar reference numerals.

FIG. 1 illustrates a schematic diagram of a centrifugal compressor energy storage thermal management system in accordance with one embodiment of the invention.

FIG. 2 illustrates a flow diagram of system control based on surge characteristics of a centrifugal compressor in accordance with one embodiment of the present invention.

FIG. 3 illustrates a flow diagram of fan gear control in system control based on surge characteristics of a centrifugal compressor in accordance with one embodiment of the present invention.

FIG. 4 illustrates a schematic diagram of a main throttling element control flow in system control based on surge characteristics of a centrifugal compressor in accordance with one embodiment of the invention.

FIG. 5 illustrates a schematic diagram of a secondary throttling element control flow in system control based on surge characteristics of a centrifugal compressor in accordance with one embodiment of the invention.

FIG. 6 illustrates a schematic diagram of a bypass valve control flow in system control based on surge characteristics of a centrifugal compressor in accordance with one embodiment of the invention.

Fig. 7 shows a schematic diagram of a characteristic curve of a centrifugal compressor in an embodiment of the invention.

Fig. 8-10 are schematic diagrams illustrating the construction of a centrifugal compressor energy storage thermal management system in accordance with an embodiment of the present invention.

FIG. 11 is a flow chart illustrating a method for controlling make-up air for an energy storage thermal management system in accordance with an embodiment of the present invention.

FIG. 12 is a flow chart illustrating a method of controlling a centrifugal compressor energy storage thermal management system in accordance with one embodiment of the present invention.

List of reference numerals:

1 compressor, 2 discharge temperature sensor, 3 discharge pressure sensor, 4 condenser, 5 fan, 6, economizer, 7 auxiliary throttle element, 8 main throttle element, 9 evaporator, 10 suction pressure sensor, 11 suction temperature sensor, 12 make-up pressure sensor, 13 make-up temperature sensor, 14 main path temperature sensor, 15 main path pressure sensor, 16 bypass valve, 17 water pump, 18 battery pack heat source, 19 water outlet temperature sensor, 20 water outlet pressure sensor, 21 compressor suction inlet, 22 low pressure shell, 23 inter-stage make-up port, 24 high low pressure connecting tube, 25 high pressure shell, 26 compressor discharge outlet, 27 low pressure impeller, 28 low pressure lock nut, 29 low pressure cap seal, 30 low pressure cap, 31 motor housing, 32 electronic stator, 33 motor rotor, 34 high pressure cap seal, 35 high pressure cap seal, 36 high pressure impeller, 37 high pressure lock nut, 38 high pressure side radial bearing, 39 low pressure side radial bearing, 40 high pressure side thrust bearing, 41 thrust disc, 42 low pressure side thrust bearing.

Detailed Description

It should be noted that the components in the figures may be shown exaggerated for illustrative purposes and are not necessarily to scale. In the drawings, identical or functionally identical components are provided with the same reference numerals.

In the present invention, unless specifically indicated otherwise, "disposed on …", "disposed over …" and "disposed over …" do not preclude the presence of an intermediate therebetween. Furthermore, "disposed on or above" … merely indicates the relative positional relationship between the two components, but may also be converted to "disposed under or below" …, and vice versa, under certain circumstances, such as after reversing the product direction.

In the present invention, the embodiments are merely intended to illustrate the scheme of the present invention, and should not be construed as limiting.

In the present invention, the adjectives "a" and "an" do not exclude a scenario of a plurality of elements, unless specifically indicated.

It should also be noted herein that in embodiments of the present invention, only a portion of the components or assemblies may be shown for clarity and simplicity, but those of ordinary skill in the art will appreciate that the components or assemblies may be added as needed for a particular scenario under the teachings of the present invention. In addition, features of different embodiments of the invention may be combined with each other, unless otherwise specified. For example, a feature of the second embodiment may be substituted for a corresponding feature of the first embodiment, or may have the same or similar function, and the resulting embodiment would fall within the disclosure or scope of the disclosure.

It should also be noted herein that, within the scope of the present invention, the terms "identical", "equal" and the like do not mean that the two values are absolutely equal, but rather allow for some reasonable error, that is, the terms also encompass "substantially identical", "substantially equal". By analogy, in the present invention, the term "perpendicular", "parallel" and the like in the table direction also covers the meaning of "substantially perpendicular", "substantially parallel".

In the present invention, the controller may be implemented in software, hardware or firmware, or a combination thereof. The controller may be present alone or as part of a component

The numbers of the steps of the respective methods of the present invention are not limited to the order of execution of the steps of the methods. The method steps may be performed in a different order unless otherwise indicated.

The invention is further elucidated below in connection with the embodiments with reference to the drawings.

FIG. 1 illustrates a schematic diagram of a centrifugal compressor energy storage thermal management system in accordance with one embodiment of the invention. As shown in fig. 1, the centrifugal compressor energy storage heat management system of the present embodiment includes: a refrigeration circuit configured to circulate a refrigerant; a heat exchange medium circuit configured to circulate a heat exchange medium to cool or heat a target device; a heat exchange device which is respectively communicated with the refrigeration loop and the heat exchange medium loop and exchanges heat so that the refrigerant in the refrigeration loop can cool the heat exchange medium in the heat exchange medium loop; and a centrifugal compressor 1 in communication with the refrigeration circuit.

Specifically, the centrifugal compressor energy storage thermal management system further comprises: a refrigeration system component configured to be disposed in a refrigeration circuit comprising a condenser 4, a fan 5, a bypass valve 16, a primary throttling element 8, a secondary throttling element 7, an economizer 6, temperature sensors (2, 11, 13, 14) and pressure sensors (3, 10, 12, 15); a coolant system assembly configured to be disposed in the heat exchange medium circuit, comprising a water pump 17, a temperature sensor 19, and a pressure sensor 20; wherein the heat exchange device is an evaporator 9; the target device is a battery pack heat source 18. Wherein the throttling element comprises an electronic expansion valve, a thermal expansion valve, a capillary tube, etc.

In the refrigeration loop, the first output end of the evaporator is respectively connected to the first input end of the centrifugal compressor and the output end of the bypass valve; the output end of the centrifugal compressor is connected to the input end of the condenser, and the input end of the bypass valve is connected to the input end of the condenser; the output end of the condenser is connected to the first input end of the economizer, the first output end of the economizer is connected to the input end of the main throttling element, and the output end of the main throttling element is connected to the first output end of the evaporator; the first output end of the economizer is also connected to the input end of the auxiliary throttling element, the output end of the auxiliary throttling element is connected to the second input end of the economizer, and the second output end of the economizer is connected to the second input end of the centrifugal compressor; the second output end of the evaporator is connected to the input end of the battery pack heat source, the output end of the battery pack heat source is connected to the input end of the water pump, and the output end of the water pump is connected to the second input end of the evaporator; the fan is arranged on the condenser, and the temperature sensor and the pressure sensor are respectively arranged at the first input end, the first output end and the second output end of the evaporator and the first output end and the second input end of the centrifugal compressor.

The centrifugal compressor is used as a power source of refrigerant in the system, the refrigerant is compressed in a centrifugal way, the compressed high-temperature refrigerant reaches the condenser through a pipeline, the electronic fan sucks normal-temperature air into the condenser fins, the condenser exchanges heat between heat of the internal high-temperature refrigerant and the air, the condensed refrigerant reaches the expansion valve through the pipeline, the expansion valve throttles the refrigerant, the throttled refrigerant rapidly expands and enters the plate heat exchanger, the throttled refrigerant absorbs heat from the cooling liquid through the plate heat exchanger in the plate heat exchanger, so that the cooling liquid is reduced to an expected temperature, the evaporated refrigerant continues to reach the filter element through the pipeline, the filter element filters impurities of the system, and the filtered refrigerant returns to the compressor again. Pressure and temperature sensors are also provided on the compressor outlet line and on the plate heat exchanger outlet line, the purpose of the sensors being for calculation of the refrigeration demand of the system and protection of the system operation.

In the heat exchange medium loop, a water pump outlet is connected with an evaporator cooling liquid side inlet, an evaporator cooling liquid side outlet is connected with a battery pack heat source inlet, and a battery pack heat source outlet is connected with a water pump inlet. In the cooling liquid circulation, the electronic water pump is used as a power source of the cooling liquid circulation, the water pump is connected with the plate heat exchanger through a water pipe, the cooling liquid is fed into the plate heat exchanger (in order to improve heat exchange efficiency, the flowing direction of the cooling liquid in the plate heat exchanger is opposite to the flowing direction of the cooling agent), after heat is transferred to the cooling agent, the cooling liquid enters the energy storage battery through a pipeline, in the energy storage battery, the heat generated by the electric core is transferred to the cooling liquid again, and the cooling liquid returns to the electronic water pump again.

Fig. 8-10 are schematic diagrams illustrating the construction of a centrifugal compressor energy storage thermal management system in accordance with an embodiment of the present invention. As shown in fig. 8 to 10, the high-speed air-bearing centrifugal compressor is composed of the following components: compressor suction port 21, low pressure casing 22, inter-stage makeup port 23, high-low pressure connection pipe 24, high pressure casing 25, compressor discharge port 26, low pressure impeller 27, low pressure lock nut 28, low pressure wheel cover seal 29, low pressure end cover 30, motor housing 31, motor stator 32, motor rotor 33, high pressure end cover 34, high pressure wheel cover seal 35, high pressure impeller 36, high pressure lock nut 37, high pressure side radial bearing 38, low pressure side radial bearing 39, high pressure side thrust bearing 40, thrust disk 41, low pressure side thrust bearing 42.

Based on the small high-speed air-floating centrifugal compressor, a system design based on the centrifugal compressor is designed. And a control method is proposed for preventing the compressor from entering the surge zone based on the system design aiming at the surge characteristic of the centrifugal compressor. The low-temperature low-pressure refrigerant gas from the evaporator enters the compressor through the air suction port, is compressed and acted by the low-pressure impeller to enter the low-pressure shell, then enters the high-pressure impeller through the high-low pressure connecting pipe to be further compressed and enter the high-pressure shell, and finally the high-temperature high-pressure refrigerant gas is discharged into the condenser through the air discharge port. The high-low pressure connecting pipe is provided with an inter-stage air supplementing hole, so that exhaust gas from an economizer can be connected to cool the exhaust gas of the low-pressure impeller, the compression power consumption of the high-pressure impeller is reduced, and the efficiency of the system is further improved.

The high-pressure impeller and the low-pressure impeller are closed impellers, so that secondary flow from the pressure surface to the suction surface of the blade caused by blade tip gaps is eliminated, and the pneumatic efficiency of the compressor is effectively improved. And the wheel cover sides of the high-pressure impeller and the low-pressure impeller are respectively provided with a sealing structure, so that the backflow effect from the outlet to the inlet of the impeller can be obviously reduced, and the efficiency of the compressor can be further improved.

The high-pressure impeller and the low-pressure impeller adopt a back-to-back design mode, the axial thrust directions of the impellers at the high pressure side and the low pressure side are opposite and offset, and the axial thrust born by the thrust bearing can be effectively reduced. The thrust bearing positions are shown in fig. 10, and one thrust bearing is arranged on each side of the thrust disc, so that axial thrust force directed to the low pressure side or the high pressure side can be received.

When the motor rotating shaft rotates, refrigerant gas is sucked into the low-pressure side radial bearing and the high-pressure side radial bearing, so that a gas film is formed to support the rotor to rotate at a high speed, the thrust rotating shaft is not contacted with the bearing, the bearing is almost free from abrasion, and mechanical loss and noise are very small. Meanwhile, the thrust bearing also forms a gas film to bear axial thrust. The thrust and radial bearing of the invention is a dynamic pressure type air bearing, and the air supply of the bearing is realized through internal circulation: the exhaust gas of the high-pressure impeller passes through a gap between the high-pressure impeller and the high-pressure end cover, then enters the high-pressure side radial bearing through a gap between the high-pressure end cover and the rotating shaft, then enters the low-pressure side radial bearing through an air gap between the motor stator and the rotor, then sequentially passes through the two thrust bearings through a gap between the thrust disc and the motor shell and a gap between the thrust disc and the low-pressure end cover, finally sequentially passes through a gap between the low-pressure end cover and the rotating shaft and a gap between the low-pressure impeller and the low-pressure end cover, enters the low-pressure impeller exhaust port, returns to the main gas path, and sequentially passes through the low-pressure shell, the high-pressure connecting pipe and the high-pressure impeller to realize internal circulation. Compared with a static pressure air bearing, the invention omits an external air supplementing channel, simplifies the system structure and improves the reliability.

The compressor adopts the motor as a high-speed permanent magnet synchronous motor, and the air bearing is a non-contact bearing when in operation, so that the air bearing can bear higher rotating speed than a common ball bearing, and the compressor with the same function force can be known according to a Euler formula delta h=U2Cu2-U1 Cu1 of the compressor, and the larger the rotating speed is, the smaller the radial size is, so that the permanent magnet synchronous motor improves the power density of the compressor.

As shown in fig. 1, when the unit is in operation, the refrigerant in the fluorine system is discharged from the compressor as high-temperature and high-pressure gas, condensed Cheng Gaowen by the condenser to form low-temperature and low-pressure liquid by the main throttling element, and formed into low-temperature and low-pressure gas by the evaporator and returned to the compressor. The air supplementing channel is used for exhausting the low-temperature and low-pressure liquid passing through the economizer to the air supplementing side of the compressor after passing through the evaporation side of the economizer. The bypass valve directly connects the inlet of the compressor with the discharge side. And cooling liquid in the cooling liquid system exchanges heat with the refrigerant through the evaporator and flows to the battery pack for cooling and radiating, and then flows to the evaporator for heat exchange and cooling after the radiating is finished.

In a second aspect of the invention, a control method for a centrifugal compressor energy storage thermal management system is provided. FIG. 12 is a flow chart illustrating a method of controlling a centrifugal compressor energy storage thermal management system in accordance with one embodiment of the present invention. As shown in fig. 12, the method includes:

Step 1201, performing start control, target frequency correction and stop control on the centrifugal compressor.

Step 1202, the main throttling element is self-learned, and the opening degree of the main throttling element is controlled according to the suction superheat degree of the centrifugal compressor.

Step 1203, performing start control, normal control, and protection control on the cooling fan.

Step 1204, performing start control and rotation speed control on the water pump.

Step 1205, air make-up control is performed by the centrifugal compressor and the auxiliary throttling element.

Step 1206, performing system control based on surge characteristics of the centrifugal compressor.

It should be noted that the numbering of the steps of the method does not limit the order in which the steps of the method are performed. The execution sequence of each step of the method can be adjusted according to actual needs by a person skilled in the art during the operation of the centrifugal compressor energy storage heat management system. For example, after the system receives the refrigeration demand command, the water pump is started according to step 1204; further, the cooling fan is started according to step 1203 and the main throttling element is started according to step 1202; starting a compressor according to step 1201 after the system is stable, wherein the compressor firstly rapidly reaches a starting rotation speed, and performing PID (proportion integration differentiation) adjustment according to a water temperature target after the operation is stable; further, surge control is performed during system operation according to step 1206.

Specifically, the compressor control method of the centrifugal compressor energy storage heat management system comprises the following steps: starting and controlling the compressor; performing target frequency correction on the compressor; and performing a shutdown control for the compressor.

The start control of the compressor includes: (1) And determining the starting condition of the compressor when the machine set is started, wherein when the machine set is electrified, all the parts are self-learned, the machine set is in a refrigeration mode (wherein the machine set automatically judges to enter the refrigeration mode when in a full-automatic mode) and has refrigeration requirements, or the machine set sends a refrigeration request from a Battery Management System (BMS). (2) The pressure equalizing operation is performed to prevent the compressor from being damaged by the load starting. It is necessary to check whether there is a large high-low pressure difference in the compressor before the compressor is started. When the high-low pressure difference of the compressor is large, a high-low pressure unloading valve (SV) is opened so as to bypass and release the high-low pressure until the high-low pressure difference of the compressor is smaller than a set safety value or the opening time of the pressure release valve exceeds 2 minutes. (3) The start-up platform is controlled, wherein after the compressor is started, the compressor frequency should be fixedly operated at the set start-up platform frequency. The frequency of the starting platform should avoid the frequency point with larger amplitude of the compressor, and avoid the influence of excessive vibration on the reliability of the compressor. (wherein the start-up platform is first identified based on the refrigeration request level sent by the BMS and is determined based on the unit water outlet temperature if there is no interaction with the BMS). (4) The coordination control is carried out, the compressor is started according to the initial requirement before starting until the compressor is loaded to the frequency of the corresponding load after the starting process is finished if the refrigerating requirement is increased during the starting process. Before the start of the compressor is finished, the whole unit is shut down if the refrigeration requirement is 0. If the compressor is already started, the shortest operating cycle of the unit must be satisfied, which is five minutes.

The target frequency correction for the compressor includes: the target frequency corrects the frequency output of the compressor based on Ps (suction pressure) in the cooling mode, so the frequency correction starts to correct two minutes after the end of the compressor start-up process, with a correction period of 40s. In the target frequency correction process, the output water temperature of the unit can be ensured to be stable at the target temperature through PID control.

The shutdown control of the compressor includes: (1) The compressor is normally shut down controlled, wherein a minimum run time is required to be followed. In order to ensure that the components of the system are not damaged during the shutdown process, the component control is required to be performed in sequence. Firstly, the compressor is closed, the pressure relief valve is opened when the compressor is closed, so that the pressure at the two sides of the inlet and the outlet of the compressor is balanced rapidly, the water pump and the cooling fan are closed after the compressor is stopped, the opening of the main throttling element (EXV_M) and the auxiliary throttling element (EXV_F) are adjusted to 50%, and SV is closed. Before the compressor is stopped, whether the single operation time of the compressor is longer than 5min is judged, if the single operation time of the compressor is shorter than five minutes, the compressor continues to work, and stopping is carried out after the compressor works for five minutes. (2) And (3) controlling the fault shutdown of the compressor, when the unit receives a fault signal and the compressor is required to be shut down immediately, directly shutting down the compressor, opening a pressure relief valve when the compressor is shut down, so that the pressure at the two sides of an inlet and an outlet of the compressor is balanced rapidly, closing a water pump and a cooling fan after the compressor is shut down, simultaneously adjusting the opening of the EXV_ M, EXV _F to 50%, and closing the SV.

The control method of the main throttling element of the centrifugal compressor energy storage heat management system comprises the following steps: causing the main throttling element to self-learn; and controlling the opening degree of the main throttling element according to the suction superheat degree of the compressor.

The main throttling element can be an electronic expansion valve, and the electronic expansion valve uses a stepping motor and does not have a position feedback function, so that a step loss phenomenon can occur in the operation process, and the electronic expansion valve needs to be self-learned in order to ensure the stable operation of the system. The conditions under which self-learning is performed include: the first condition is that the unit is electrified; the second condition is that after the machine set is electrified, the compressor stops for the 10 th time and then self-learning is carried out (wherein, counting is restarted after self-learning, and the next self-learning judging period is entered); and the third condition and the machine set have no refrigeration requirement. When the first condition is met or when the second condition and the third condition are met, the electronic expansion valve performs self-learning, the compressor is in a closed state in the self-learning process, and the rest parts of the system keep the current state unchanged.

When the self-learning is carried out, the electric electronic expansion valve moves 500 steps to the minimum position and the electromagnetic electronic expansion valve moves 500 steps to the maximum position when the first condition is met; when the second condition and the third condition are met, the electric electronic expansion valve moves 500 steps to the minimum position, and the electromagnetic electronic expansion valve moves 500 steps to the minimum position; wherein the total number of steps of the electric electronic expansion valve and the electromagnetic electronic expansion valve is 500 steps.

The conditions for the electronic expansion valve to withdraw from learning include: when the power is firstly applied, self-learning reset is performed by driving a feedback self-learning completion signal, and self-learning completion is determined; or when the position of the electronic expansion valve is less than 5 and the 500-step running time is more than 16s, determining that the self-learning is finished.

Controlling the opening of the main throttling element according to the suction superheat degree of the compressor comprises: setting a target suction superheat degree, measuring the current suction superheat degree of the compressor, and outputting the opening of a main throttling element according to the target suction superheat degree and the current suction superheat degree of the compressor when a program is executed, wherein the opening section of the main throttling element is determined according to the opening range of the main throttling element, the target suction superheat degree is converted according to the water inlet temperature of the unit, and the higher the water inlet temperature is, the higher the suction superheat degree target is, the lower the water inlet temperature is, and the lower the suction superheat degree is.

Control of the fan includes start-up control, general control and protective measures. The starting control defines the initial rotating speed of the cooling fan when the cooling fan is started and the relation between the rotating speed and the outdoor environment temperature; the normal control is a method of correcting the rotation speed of the cooling fan when the unit is in a normal, smooth operation. When the system is running, the increase and decrease of the cooling fan rotation speed is related with the corresponding control pressure.

In the system operation mode, the heat exchange effect between the condenser and the air side can be effectively increased/reduced by controlling the increase/decrease of the rotation speed of the cooling fan, so that the heat exchange effect is reflected on the corresponding pressure value. However, when some characteristics of the system are about to touch the boundary values, protection measures are required to quickly adjust the rotational speed of the fan to suppress or avoid the occurrence of a severe condition. On the premise that the compressor does not surge, the rotating speed of the fan is preferentially increased, the rotating speed of the air compressor is ensured to be as low as possible, and the coefficient of performance (COP) of the system is further increased.

Controlling the water pump includes controlling the start of the water pump and controlling the rotational speed of the water pump. In the starting process of the water pump, in order to avoid the water hammer effect, the starting rotating speed and the frequency raising rate of the water pump need to be controlled. The rotation speed of the water pump directly influences the heat exchange efficiency of the plate heat exchanger and is required to be matched with the rotation speed of the compressor so as to achieve the aim of maximum energy conservation; the rotation speed of the water pump influences the heat exchange of the battery, and the temperature difference between the water inlet and the water outlet of the battery is required to be ensured according to the requirement of the upper computer, so that the larger rotation speed of the water pump is required to be taken as the target rotation speed of the water pump according to the two conditions.

FIG. 11 is a flow chart illustrating a method for controlling make-up air for an energy storage thermal management system in accordance with an embodiment of the present invention. As shown in fig. 11, controlling the intermediate air supply may include:

Step 1101, determining a discharge superheat degree and a suction superheat degree of the compressor 1.

And 1102, adjusting the auxiliary throttle valve 7 according to the exhaust superheat degree and the suction superheat degree.

The method is specifically described below with reference to specific examples.

The present superheat degree of the exhaust gas of the compressor 1 can be calculated according to the measured values of the exhaust gas temperature sensor 2 and the exhaust gas pressure sensor 3: and the temperature of the Texhaust is the saturation temperature corresponding to the high pressure Texhaust.

The suction superheat of the compressor 1 can be calculated based on the measurement values of the suction pressure sensor 10 and the suction temperature sensor 11: t inspiration temperature-T saturation temperature corresponding to low pressure.

The present superheat degree of the air injection of the compressor 1 can be calculated from the measured value of the air-supply temperature sensor 13 and the air-supply pressure sensor 12: the T jet temperature is the saturation temperature corresponding to the T jet pipe pressure.

The initial opening degree of the auxiliary throttle valve 7 is set according to the frequency of the compressor 1. And the auxiliary throttle valve 7 is further adjusted after the energy storage thermal management system unit runs away from the starting platform or after the compressor 1 is continuously started and operated for 3min, that is, after the energy storage thermal management system can continuously and stably operate.

The manner of adjustment of the auxiliary throttle valve 7 is explained in detail below for different frequencies of the compressors 1.

When the frequency of the compressor 1 is 20-50RPS, the initial opening of the auxiliary throttle valve 7 is set to 80P, and the adjustment of the auxiliary throttle valve 7 includes:

when the superheat degree of the exhaust is less than 5K, the valve is forbidden to be opened;

when the exhaust superheat degree is less than or equal to 5K and less than or equal to 10K, the auxiliary throttle valve 7 takes the air injection superheat degree 5K as a target to adjust;

when the exhaust superheat degree is less than 10K and less than 15K, the auxiliary throttle valve 7 takes the air injection superheat degree 4K as a target to adjust;

when the exhaust superheat degree is less than or equal to 15K and less than 20K, the auxiliary throttle valve 7 takes the air injection superheat degree 3K as a target to adjust; and

when the superheat degree of the exhaust gas is more than 20K or the temperature of the exhaust gas is more than or equal to 100 ℃, the auxiliary throttle valve 7 adjusts and cools with the superheat degree of the jet gas of 1K as a target.

When the frequency of the compressor 1 is 50-70RPS, the initial opening of the auxiliary throttle valve 7 is set to 150P, and the adjustment of the auxiliary throttle valve 7 includes:

when the superheat degree of the exhaust is less than 5K, the valve is forbidden to be opened;

when the exhaust superheat degree is less than or equal to 5K and less than or equal to 10K, the auxiliary throttle valve 7 takes the air injection superheat degree 5K as a target to adjust;

when the exhaust superheat degree is less than 10K and less than 15K, the auxiliary throttle valve 7 takes the air injection superheat degree 4K as a target to adjust;

When the exhaust superheat degree is less than or equal to 15K and less than 20K, the auxiliary throttle valve 7 takes the air injection superheat degree 3K as a target to adjust; and

when the superheat degree of the exhaust gas is more than 20K or the temperature of the exhaust gas is more than or equal to 100 ℃, the auxiliary throttle valve 7 adjusts and cools with the superheat degree of the jet gas of 1K as a target.

When the frequency of the compressor 1 is 70-90RPS, the initial opening of the auxiliary throttle valve 7 is set to 250P, and the adjustment of the auxiliary throttle valve 7 includes:

when the superheat degree of the exhaust is less than 6K, the valve is forbidden to be opened;

when the exhaust superheat degree is less than or equal to 6K and less than or equal to 10K, the auxiliary throttle valve 7 takes the air injection superheat degree 5K as a target to adjust;

when the exhaust superheat degree is less than 10K and less than 15K, the auxiliary throttle valve 7 takes the air injection superheat degree 4K as a target to adjust;

when the exhaust superheat degree is less than or equal to 15K and less than 20K, the auxiliary throttle valve 7 takes the air injection superheat degree 3K as a target to adjust; and

when the superheat degree of the exhaust gas is more than 20K or the temperature of the exhaust gas is more than or equal to 100 ℃, the auxiliary throttle valve 7 adjusts and cools with the superheat degree of the jet gas of 1K as a target.

When the frequency of the compressor 1 is 90-120RPS, the initial opening of the auxiliary throttle valve 7 is set to 300P, and the adjustment of the auxiliary throttle valve 7 includes:

when the superheat degree of the exhaust is less than 8K, the valve is forbidden to be opened;

When the exhaust superheat degree is less than or equal to 8K and less than or equal to 10K, the auxiliary throttle valve 7 takes the air injection superheat degree 5K as a target to adjust;

when the exhaust superheat degree is less than 10K and less than 15K, the auxiliary throttle valve 7 takes the air injection superheat degree 4K as a target to adjust;

when the exhaust superheat degree is less than or equal to 15K and less than 20K, the auxiliary throttle valve 7 takes the air injection superheat degree 3K as a target to adjust; and

when the superheat degree of the exhaust gas is more than 20K or the temperature of the exhaust gas is more than or equal to 100 ℃, the auxiliary throttle valve 7 adjusts and cools with the superheat degree of the jet gas of 1K as a target.

Further, protection control can be performed based on the air return superheat degree (air suction superheat degree) of the energy storage thermal management system, which includes:

when the superheat degree of the return air is more than or equal to 10K, the auxiliary throttle valve 7 is adjusted according to the set opening degree, and the maximum opening degree is 480P;

when the superheat degree of the return air is less than 5K and less than 10K, the valve opening action rate of the auxiliary throttle valve 7 is limited to 4P/S, and the maximum opening degree is 300P;

when the superheat degree of the return air is less than or equal to 3K and less than or equal to 5K, the auxiliary throttle valve 7 prohibits valve opening, and the maximum opening degree is 200P, wherein the current opening degree is kept when the opening degree is less than 200P, and the opening degree is reduced to 200P when the opening degree is more than 200P;

when the superheat degree of the return air is less than 3K, the closing speed of the auxiliary throttle valve 7 is 2P/S, and the maximum opening degree is 100P, wherein when the superheat degree of the return air is still less than 3K in the time counting 30S, the minimum opening degree is adjusted to 60P (when the current opening degree is more than 100P, the minimum opening degree is immediately adjusted to 100P, and when the current opening degree is less than 100P, the minimum opening degree is kept unchanged), and when the accumulation time counting 60S is still less than 3K, the opening degree of the current auxiliary throttle valve 7 is closed.

In addition, the centrifugal compressor has a surge phenomenon, which refers to abnormal compressor vibration occurring when the flow rate of the centrifugal compressor is reduced to a certain extent, which threatens the safe use of the compressor and needs to be avoided from entering, the centrifugal compressor sometimes suddenly generates strong vibration during the production operation, the flow rate and the pressure of the gas medium also generate large pulsation, and the surge phenomenon is accompanied by a periodically clumsy 'calling' sound, and strong noise caused by the gas flow fluctuation to cause 'calling to call' in a pipe network, and the phenomenon is called a surge condition of the centrifugal compressor. Fig. 7 shows a schematic diagram of a characteristic curve of a centrifugal compressor according to an embodiment of the present invention, in which a control method for preventing the compressor from entering a surge region is designed due to a surge characteristic of the centrifugal compressor as shown in fig. 7.

FIG. 2 illustrates a flow diagram of system control based on surge characteristics of a centrifugal compressor in accordance with one embodiment of the present invention. As shown in fig. 2, the control operation of the system is performed according to the surge characteristics of the centrifugal compressor; detecting the pressure ratio/flow of the compressor to obtain a current running state point, judging whether the current running state point reaches a surge protection area or not according to the current running state point, judging whether the gear of the fan is in an intervention state or not if the gear of the fan is in the intervention state, and otherwise, continuously detecting the pressure ratio/flow of the compressor to obtain the current running state point; when judging whether the gear of the fan is in an interference state, if so, judging whether the opening of the main throttling element is in interference regulation; otherwise, adjusting the gear of the fan according to the surge curve; judging whether the opening of the main throttling element is interfered and regulated or not, if yes, judging whether the auxiliary throttling element is interfered and regulated or not, otherwise, regulating the main throttling element according to a surge curve; judging whether the auxiliary throttling element intervenes in control to intervene in adjustment or not when judging whether the auxiliary throttling element intervenes in control to intervene in adjustment, if so, judging whether a bypass valve is opened or not, otherwise, adjusting the auxiliary throttling element according to a surge curve; judging whether the current running state point reaches a surge alarm point or not if the bypass valve is judged to be opened or not, otherwise, opening the bypass valve and adjusting; and when judging whether the current running state point reaches the surge alarm point, if so, stopping the compressor for alarm, otherwise, returning to detect the pressure ratio/flow of the compressor to obtain the current running state point. FAN means a FAN gear, and during normal control, the FAN gear corresponds to HP (system high pressure/exhaust pressure), that is, the higher the FAN gear is required when HP is high, assuming that the FAN control gear is a, it may be any one of 0 to 30 bar r, the B value is set to 36 bar r, and as long as a does not exceed B, it can be determined that a is a normal value, and the FAN gear is normal control.

FIG. 3 illustrates a flow chart of fan gear control in system control based on surge characteristics of a centrifugal compressor in accordance with one embodiment of the present invention. As shown in fig. 3, when judging whether the gear of the fan is in an intervention state, judging whether the current unit pressure is smaller than a first threshold value, if yes, the gear of the fan is in an intervention regulation state, and if not, the unit stops and alarms; when the fan gear is in the intervention adjustment state, the fan gear is adjusted to be larger or smaller, whether the fan intervention time is larger than a second threshold value is judged, and if yes, the main throttling element opening intervention adjustment is carried out.

FIG. 4 illustrates a flow chart of a main throttling element control in system control based on surge characteristics of a centrifugal compressor in accordance with one embodiment of the invention. As shown in fig. 4, when judging whether the opening degree of the main throttling element is in an intervention state, judging whether the current unit pressure is smaller than a third threshold value, if so, the main throttling element is in the intervention regulation state, otherwise, the unit stops and alarms; when the main throttling element is in an intervention regulation state, judging whether the superheat degree of the return air is smaller than a fourth threshold value, if so, the main throttling element acts, otherwise, the main throttling element exits the intervention state; and judging whether the intervention time of the main throttling element is larger than a fifth threshold value, and if so, performing the intervention adjustment of the opening degree of the auxiliary throttling element.

FIG. 5 illustrates a flow chart of auxiliary throttling element control in system control based on surge characteristics of a centrifugal compressor in accordance with one embodiment of the invention. As shown in fig. 5, when judging whether the opening of the auxiliary throttling element is in an intervention state, selecting a control strategy of the auxiliary throttling element according to the supercooling degree of the main path, judging whether the superheat degree of exhaust is smaller than a sixth threshold value, if yes, judging whether the intervention time of the auxiliary throttling element is larger than a seventh threshold value, otherwise, exiting the intervention state of the auxiliary throttling element; and judging whether the intervention time of the auxiliary throttling element is greater than a seventh threshold value, and if so, performing bypass valve intervention adjustment.

FIG. 6 illustrates a bypass valve control flow diagram in system control based on surge characteristics of a centrifugal compressor in accordance with one embodiment of the invention. As shown in fig. 6, when judging whether the bypass valve intervenes, judging whether the bypass valve is opened, if yes, exiting the bypass valve intervention regulation, otherwise opening the bypass valve.

The centrifugal compressor has no oil return system, and the reliability of the compressor and the system is high. The bearing is not contacted with the motor shaft during operation, the bearing abrasion is small, and the service life is long. And the middle pipe air supplementing hole is convenient for realizing inter-stage cooling and reducing the power consumption of the compressor. The closed impeller and the impeller cover are sealed at the side, so that leakage and backflow loss are reduced, and the pneumatic efficiency of the compressor is improved. And the back-to-back impeller design reduces the axial thrust. The internal circulation dynamic pressure air bearing does not need an additional air supplementing pipeline, and has a simple and reliable structure. The high-speed permanent magnet synchronous motor is adopted, so that the compressor has high power density and small volume and mass.

For this system carrying the present centrifugal compressor: the system can fully utilize all parts of the system, avoid the compressor from entering a surge area, protect the compressor, and control and regulate successively according to the state points of the compressor and the set priority sequence of the system.

In summary, the above embodiments describe different configurations of the energy storage thermal management system of the centrifugal compressor in detail, and of course, the present invention includes, but is not limited to, the configurations listed in the above embodiments, and any matters of transformation based on the configurations provided in the above embodiments fall within the scope of protection of the present invention. One skilled in the art can recognize that the above embodiments are illustrative.

While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not limitation. It will be apparent to those skilled in the relevant art that various combinations, modifications, and variations can be made therein without departing from the spirit and scope of the invention. Thus, the breadth and scope of the present invention as disclosed herein should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.

Claims (10)

1. A method for controlling an energy storage thermal management system of a centrifugal compressor, comprising:

performing start control, target frequency correction and stop control on the centrifugal compressor;

the main throttling element is self-learned, and the opening degree of the main throttling element is controlled according to the suction superheat degree of the centrifugal compressor;

the method comprises the steps of performing starting control, normal control and protection control on a cooling fan;

starting control and rotating speed control are carried out on the water pump;

the air supplementing control is carried out through a centrifugal compressor and an auxiliary throttling element; and

the system control is based on the surge characteristics of the centrifugal compressor.

2. The method of claim 1, wherein the controlling the start of the centrifugal compressor comprises:

when the energy storage heat management system of the centrifugal compressor is electrified, each component of the energy storage heat management system of the centrifugal compressor is self-learned, and the energy storage heat management system of the centrifugal compressor is started when in a refrigeration mode and has refrigeration requirements; or when the energy storage heat management system of the centrifugal compressor receives a refrigeration request sent by the battery management system, starting the centrifugal compressor; and/or

Checking the high-low pressure difference of the centrifugal compressor when the centrifugal compressor is started, and opening a pressure relief valve to carry out bypass pressure relief when the high-low pressure difference is larger than a safety value, wherein the pressure relief valve is closed when the high-low pressure difference is smaller than the safety value or the pressure relief time exceeds a threshold time; and/or

Determining the starting platform frequency of the centrifugal compressor according to the refrigerating request grade sent by the battery management system or according to the water outlet temperature of the energy storage thermal management system of the centrifugal compressor; and/or

If the refrigeration demand increases during the start-up of the centrifugal compressor, the centrifugal compressor is still started according to the initial refrigeration demand and is reloaded to the load frequency after the start-up process is completed; if the refrigeration requirement becomes zero in the starting process of the centrifugal compressor, closing the energy storage heat management system of the centrifugal compressor; and if the refrigeration requirement becomes zero after the start-up process of the centrifugal compressor is finished, operating the centrifugal compressor until the shortest operation period is satisfied, and then closing the centrifugal compressor.

3. The method of claim 1, wherein performing target frequency correction on the centrifugal compressor comprises:

When the centrifugal compressor energy storage thermal management system is in a refrigeration mode, the frequency output of the centrifugal compressor is corrected according to the suction pressure of the centrifugal compressor, wherein the frequency output of the centrifugal compressor is corrected through PID control so as to ensure that the outlet water temperature of the centrifugal compressor energy storage thermal management system is stable within a target temperature range.

4. The method of claim 1, wherein the controlling the shutdown of the centrifugal compressor comprises:

at normal shutdown, closing the centrifugal compressor, wherein a pressure release valve is opened to balance the pressure of the inlet side and the outlet side of the centrifugal compressor when the centrifugal compressor is closed, and closing the water pump and the cooling fan after the centrifugal compressor is closed, adjusting the opening degrees of the main throttle element and the auxiliary throttle element to 50%, and closing the pressure release valve, wherein the centrifugal compressor is closed after the centrifugal compressor is operated to meet the shortest operation period; and/or

At the time of the malfunction stop, the centrifugal compressor is turned off when the centrifugal compressor receives the malfunction signal, wherein the relief valve is opened to balance the pressure of the inlet side and the outlet side of the centrifugal compressor when the centrifugal compressor is turned off, and the water pump and the cooling fan are turned off after the centrifugal compressor is turned off, the opening degrees of the main throttle element and the auxiliary throttle element are adjusted to 50%, and the relief valve is turned off.

5. The method of claim 1, wherein the main throttling element comprises an electric electronic expansion valve or an electromagnetic electronic expansion valve, and the total number of steps of the electric electronic expansion valve or the electromagnetic electronic expansion valve is 500 steps, and wherein the self-learning of the main throttling element comprises:

when the centrifugal compressor energy storage heat management system is electrified, the electric electronic expansion valve is enabled to move 500 steps to the minimum position or the electromagnetic electronic expansion valve is enabled to move 500 steps to the maximum position, and when self-learning reset is carried out, self-learning completion is determined through driving feedback of a self-learning completion signal; or alternatively

After the energy storage heat management system of the centrifugal compressor is powered on, the centrifugal compressor is stopped for the tenth time and no refrigeration requirement exists, the electric electronic expansion valve is made to move 500 steps to the minimum position or the electromagnetic electronic expansion valve is made to move 500 steps to the minimum position, and when the position of the main throttling element is smaller than 5 and the running time of 500 steps is longer than 16s, the self-learning is determined to be completed.

6. The control method of a centrifugal compressor energy storage heat management system according to claim 1, wherein controlling the opening degree of the main throttle element according to the suction superheat degree of the centrifugal compressor comprises:

Setting target suction superheat degree, measuring the suction superheat degree of the current centrifugal compressor, and determining the opening degree of a main throttling element according to the target suction superheat degree and the suction superheat degree of the current centrifugal compressor, wherein the opening degree interval of the main throttling element is determined according to the opening degree range of the main throttling element, and the target suction superheat degree is determined according to the water inlet temperature of an energy storage heat management system of the centrifugal compressor.

7. The control method of a centrifugal compressor energy storage heat management system according to claim 1, wherein the start-up control of the cooling fan includes controlling an initial rotational speed of the cooling fan and a relationship between the initial rotational speed and an outdoor ambient temperature; the general control of the cooling fan comprises adjusting the rotation speed of the cooling fan according to the control pressure during the operation of the centrifugal compressor energy storage heat management system; and the cooling fan performs protection control, including adjusting the rotation speed of the cooling fan to inhibit the occurrence of a severe condition when the characteristic of the centrifugal compressor energy storage heat management system touches a boundary value; and/or

The starting control of the water pump comprises the steps of controlling the starting rotating speed and the frequency raising speed of the water pump when the water pump is started so as to inhibit the water hammer effect; and determining the target rotating speed of the water pump according to the heat exchange of the battery and the water inlet and outlet temperature difference of the battery.

8. The control method of a centrifugal compressor energy storage thermal management system according to claim 1, wherein the air supply control by the centrifugal compressor and the auxiliary throttle element comprises:

determining the exhaust superheat degree and the suction superheat degree of the centrifugal compressor; and

and adjusting the auxiliary throttling element according to the exhaust superheat degree and the suction superheat degree.

9. The method of claim 1, wherein the system control according to the surge characteristics of the centrifugal compressor comprises:

detecting the pressure ratio/flow of the compressor to obtain a current running state point, judging whether the current running state point reaches a surge protection area or not according to the current running state point, judging whether the gear of the fan is in an intervention state or not if the gear of the fan is in the intervention state, and otherwise, continuously detecting the pressure ratio/flow of the compressor to obtain the current running state point;

when judging whether the gear of the fan is in an interference state, if so, judging whether the opening of the main throttling element is in interference regulation; otherwise, adjusting the gear of the fan according to the surge curve;

judging whether the opening of the main throttling element is interfered and regulated or not, if yes, judging whether the auxiliary throttling element is interfered and regulated or not, otherwise, regulating the main throttling element according to a surge curve;

Judging whether the auxiliary throttling element intervenes in control to intervene in adjustment or not when judging whether the auxiliary throttling element intervenes in control to intervene in adjustment, if so, judging whether a bypass valve is opened or not, otherwise, adjusting the auxiliary throttling element according to a surge curve;

judging whether the current running state point reaches a surge alarm point or not if the bypass valve is judged to be opened or not, otherwise, opening the bypass valve and adjusting; and

and when judging whether the current running state point reaches the surge alarm point, if so, stopping the compressor for alarm, otherwise, returning to detect the pressure ratio/flow of the compressor to obtain the current running state point.

10. A centrifugal compressor energy storage thermal management system, characterized by a controller configured to perform the method of one of claims 1-9.