Control method for refrigerating system and refrigerating system

Abstract

The invention provides a control method for a refrigerating system and the refrigerating system. The refrigerating system comprises a compressor, a condenser, a first throttling element, an evaporator, an air supplementing device and a controller, the control method comprises the steps that a starting instruction for starting the compressor is received, and the temperature of the compressor is obtained; under the condition that the temperature of the compressor is smaller than or equal to the preset temperature threshold value, preset heating voltage is input into the compressor, and a motor winding of the compressor emits heat to heat the compressor; under the condition that the temperature of the compressor is larger than the preset temperature threshold value, the preset starting voltage is input into the compressor, the compressor is normally started, the heating efficiency is high, and the problems that due to the fact that lubricating oil is discharged out of the compressor along with refrigerants due to low temperature, motor loads are too large, and abrasion of moving parts such as bearings and pistons is aggravated can be solved; moreover, opening and closing delay or clamping stagnation of the gulp valve plate and even valve plate faults can be prevented, and fatigue damage of the valve plate is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to a vapor compression refrigeration system, in particular to a control method for a refrigeration system and a refrigeration system. BACKGROUND

[0002] In the existing air conditioning technology, single-stage air-supply enthalpy-increasing rotary compressors are generally divided into piston cutting air-supply mode and one-way valve air-supply mode.

[0003] The piston cutting air-supply mode has the advantages of simple structure and high reliability, but the air-supply port of the piston cutting air-supply mode is generally designed to be small due to structural limitations, the air-supply resistance is large and the air-supply amount is limited, and the piston cutting air-supply mode has high requirements for the design position of the air-supply port, and the optimal air-supply port position is different under different working conditions, which results in that the piston cutting air-supply mode cannot adapt to the change of working conditions well, especially when facing a wide range of working conditions, the optimal air-supply amount cannot be achieved and gas backflow phenomenon occurs to different degrees.

[0004] Compared with the piston cutting air-supply mode, the one-way valve air-supply mode has the advantages of large air-supply amount, less gas backflow and strong adaptability to full working conditions, and is therefore widely used. However, the head of the air-supply one-way valve is usually designed as a circular arc shape because the processing technology of the circular arc shape is good and the head stiffness is uniformly distributed, but in order to improve the sealing performance of the air-supply valve and reduce the deformation thereof, the diameter of the circular head of the air-supply one-way valve should be larger than the diameter of the protruding arc outer edge of the air-supply valve air-supply port. When the air-supply one-way valve is in a closed state, the gap between the head of the valve and the air-supply valve seat will be filled with refrigeration oil to form a vacuum, and a large pressure difference is required to open the air-supply valve, which causes a large air-supply pressure loss of the air-supply one-way valve and is not conducive to improving the air-supply capacity.

[0005] In order to increase the amount of air supply, it is usually necessary to increase the cross-sectional area of ​​the air supply port, reduce the stiffness of the middle connection of the air supply valve plate, or increase the lift of the air supply valve plate. Among them, increasing the cross-sectional area of ​​the air supply port can reduce the flow resistance and increase the amount of air supply to a certain extent, but the air supply port with a large cross-sectional area requires a larger air supply valve plate to increase the stiffness of the valve plate head and reduce deformation to ensure sealing. This will result in a larger pressure difference between the two ends of the air supply valve plate to overcome the vacuum negative pressure before the air supply valve plate can be opened when the compressor is supplying air (the air supply valve plate opens with a delay, and too high an air supply pressure is not conducive to the heat exchange of the economizer of the air conditioning system), resulting in a reduction in the effective air supply time and is not conducive to improving the air supply capacity; reducing the stiffness of the connection between the head and tail of the air supply valve plate can Reduce the pressure difference required to open the air supply valve when the compressor is supplying air, so as to increase the air supply volume (improve the effective air supply time and the heat exchange efficiency of the air-conditioning system economizer). However, reducing the stiffness of the connection part of the air supply valve will slow down the closing speed of the air supply valve. When the pressure in the cylinder compression chamber is greater than the air supply pressure, the delay in closing the air supply valve will cause the high-pressure gas in the cylinder compression chamber to flow back outward from the air supply port, which will also reduce the air supply capacity to a certain extent. Under the condition of a certain stiffness of the air supply valve connection part, increasing the lift of the air supply baffle will cause the air supply valve to close late and the compressed gas to flow back.

[0006] Taking all factors into consideration, it is necessary to provide a control method for a refrigeration system and a refrigeration system that can reliably increase the amount of air supply. Summary of the Invention

[0007] An object of a first aspect of the present invention is to overcome at least one technical drawback of the prior art and provide a valve assembly for a compressor.

[0008] A further object of the first aspect of the present invention is to enable the system to adapt to complex working conditions.

[0009] Another further object of the first aspect of the present invention is to optimize the refrigerant circulation efficiency.

[0010] An object of the second aspect of the present invention is to provide a refrigeration system having an air supplement device.

[0011] A further object of the second aspect of the present invention is to reduce the supplemental gas pressure loss.

[0012] According to a first aspect of the present invention, a control method for a refrigeration system is provided, wherein the refrigeration system includes a compressor, and the control method includes:

[0013] receiving a start-up instruction for starting the compressor and obtaining the temperature of the compressor;

[0014] When the temperature of the compressor is less than or equal to a preset temperature threshold, inputting a preset heating voltage to the compressor so as to heat the motor winding of the compressor;

[0015] When the temperature of the compressor is greater than the preset temperature threshold, a preset starting voltage is input to the compressor so that the compressor starts normally.

[0016] The control method of the present invention, after receiving the start-up command of the compressor, first heats the motor winding to heat up the compressor and then starts the compressor normally when the temperature of the compressor is low. Not only is the heating efficiency high, it can also avoid the problem of excessive motor load caused by the lubricating oil being discharged from the compressor along with the refrigerant due to low temperature, and aggravated wear of moving parts such as bearings and pistons. It can also prevent delays or jams in the opening and closing of the air supply valve, or even valve failure (such as seal failure, air supply channel blockage), reduce fatigue damage to the valve, avoid undesirable increase in system energy efficiency, and enable the system to adapt to complex working conditions.

[0017] Optionally, the temperature of the compressor is the temperature of a position of the compressor casing corresponding to the bottom oil pool.

[0018] The present invention uses the temperature of the bottom of the compressor shell to determine whether the compressor needs to be preheated, can accurately evaluate the impact of the lubricating oil state on the operation of the compressor, and improve the starting speed of the compressor.

[0019] Optionally, the refrigeration system further includes an air supply device, and the control method further includes, after the step of normally starting the compressor:

[0020] Determining whether the compressor is overloaded;

[0021] When the compressor is overloaded, the air supply device is controlled to supply gaseous refrigerant to the compressor.

[0022] The present invention supplements gaseous refrigerant to the compressor when the compressor is overloaded, and by adjusting the refrigerant flow rate, it can improve the circulation lubrication effect of the lubricating oil, reduce the motor temperature, optimize the circulation efficiency, and improve the service life and safety performance of the refrigeration system.

[0023] Optionally, the step of determining whether the compressor is overloaded includes:

[0024] It is determined whether the operating frequency of the compressor is greater than or equal to a preset frequency threshold. If so, it is determined that the compressor is overloaded.

[0025] The present invention determines whether it is necessary to supplement the gaseous refrigerant to the compressor according to the frequency of the compressor, and can realize real-time judgment of the workload without adding additional sensors. The hardware cost is low and the control logic is simple.

[0026] Optionally, the step of determining whether the compressor is working overload comprises:

[0027] determining whether the ratio of the discharge pressure to the suction pressure of the compressor is greater than or equal to a preset pressure ratio threshold, and if so, determining that the compressor is working overload.

[0028] The present application determines whether the compressor needs to be supplemented with gaseous refrigerant according to the ratio of the discharge pressure to the suction pressure of the compressor, which can more directly reflect the working load of the compressor and avoid control failure caused by abnormal electrical parameters.

[0029] According to a second aspect of the present application, there is provided a refrigeration system comprising:

[0030] a compressor, a condenser, a first throttling element and an evaporator connected in sequence to form a main refrigeration circuit;

[0031] a gassing device for supplementing the compressor with gaseous refrigerant; and

[0032] a controller configured to perform the control method of any one of the above.

[0033] The refrigeration system of the present application, after receiving a start-up instruction of the compressor, first causes the motor winding to heat up to warm up the compressor before starting the compressor normally, which not only has high heating efficiency, but also can prevent the problems of excessive load of the motor, aggravation of wear of moving parts such as bearings and pistons caused by the lubricating oil being discharged from the compressor with the refrigerant due to low temperature, and can prevent delay or jamming of the opening and closing of the gassing valve, even valve failure (such as seal failure, gassing passage blockage), reduce fatigue damage of the valve, avoid unexpected increase of system energy efficiency, and make the system adapt to complex working conditions.

[0034] Optionally, the gassing device comprises:

[0035] a second throttling element and a gassing tank connected in sequence with the compressor and the condenser to form a gassing circuit, and

[0036] a solenoid valve connected in series between the condenser and the second throttling element for opening and closing the gassing circuit to supplement the compressor with gaseous refrigerant when the gassing circuit is turned on.

[0037] The present application forms a gassing bypass circuit independent of the main refrigeration circuit by the second throttling element, the gassing tank and the solenoid valve with the compressor and the condenser, so that the high-pressure liquid refrigerant output by the condenser is reduced in pressure to a medium-pressure state by the second throttling element, and then partially evaporates into a gaseous state in the gassing tank due to sudden pressure drop to supplement the compressor, which can avoid the impact of the supplemented gaseous refrigerant on the compressor, improve the operation reliability of the refrigeration system and prolong the service life of the device.

[0038] Optionally, the compressor further includes an air supply valve assembly, and the air supply valve assembly includes:

[0039] The mounting member is formed with at least one gas outlet for the gaseous refrigerant to flow out; and

[0040] At least one valve plate, each valve plate includes a tail portion fixedly connected to the mounting member, a head portion for opening and closing one of the air outlets, and a connecting portion connecting the head portion and the tail portion.

[0041] The control strategy of the present invention combined with the one-way air supply valve plate can reduce valve plate wear and avoid valve plate sealing failure causing air supply abnormalities, reduce the requirements for the overlapping area between the valve plate and the periphery of the air outlet, and can reduce the size of the valve plate head while ensuring the reliability of the compressor operation.

[0042] Optionally, the air outlet is circular; and

[0043] The head is polygonal, with the number of sides being greater than or equal to 5.

[0044] The present invention uses a polygonal valve plate head to close the circular air outlet, which can improve the stiffness of the head and reduce deformation. While ensuring the sealing of the valve plate and the stiffness of the head, it reduces the vacuum negative pressure formed on the mounting part due to the overlap of the valve plate head and the periphery of the air outlet, thereby reducing the air replenishment pressure loss.

[0045] Optionally, the shortest distance between the vertex of the corner projected by the head on the opening plane of the air outlet and the edge of the air outlet is 0.8 mm to 1.6 m.

[0046] The present invention sets the angular apex of the valve plate head to be within the range of 0.8mm to 1.6mm protruding from the air outlet. Compared with the circular valve plate head protruding more than 3mm from the air outlet in the prior art, it can effectively reduce the area of ​​negative pressure formed between the valve plate head and the periphery of the air outlet while ensuring sealing, thereby effectively reducing the loss of air supply pressure.

[0047] Based on the following detailed description of specific embodiments of the present invention in conjunction with the accompanying drawings, those skilled in the art will become more aware of the above and other objects, advantages and features of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Hereinafter, some specific embodiments of the present invention will be described in detail in an exemplary and non-limiting manner with reference to the accompanying drawings. The same reference numerals in the accompanying drawings indicate the same or similar components or parts. It should be understood by those skilled in the art that these drawings are not necessarily drawn to scale. In the accompanying drawings:

[0049] Figure 1 is a schematic structural diagram of a refrigeration system according to one embodiment of the present invention;

[0050] Figure 2 yes Figure 1 A schematic top view of the middle valve assembly;

[0051] Figure 3 It is along Figure 2 A schematic cross-sectional view taken along the cutting line AA in FIG.

[0052] Figure 4 yes Figure 3 A schematic top view of the middle valve plate;

[0053] Figure 5 yes Figure 3 A schematic top view of the middle limit baffle;

[0054] Figure 6 yes Figure 5 A schematic side view of the limit stop shown;

[0055] Figure 7 is a schematic structural diagram of a control circuit according to one embodiment of the present invention;

[0056] Figure 8 is a schematic flow chart of a control method for a refrigeration system according to an embodiment of the present invention.

[0057] Reference numerals:

[0058] Refrigeration system 100;

[0059] Compressor 110; housing 111; motor 112; stator 112a; rotor 112b; crankshaft 113; main bearing 114; auxiliary bearing 115; first cylinder 116; second cylinder 117;

[0060] Condenser 120; first throttling element 130; evaporator 140; gas-liquid separator 150; second throttling element 160; gas supply tank 170; solenoid valve 180; economizer 190;

[0061] Valve assembly 200; mounting member 210; air supply channel 211; air outlet 212; valve plate 220; tail portion 221; head portion 222; connecting portion 223; stopper plate 230; stopper portion 231; fastener 240;

[0062] Controller 310 ; processing unit 311 ; storage unit 312 ; computer program 313 ; temperature sensor 320 ; exhaust pressure sensor 330 ; intake pressure sensor 340 . DETAILED DESCRIPTION

[0063] Figure 1 FIG is a schematic structural diagram of a refrigeration system 100 according to an embodiment of the present invention. Figure 1 The refrigeration system 100 may generally include a compressor 110, a condenser 120, a first throttling element 130, and an evaporator 140 connected in sequence to form a refrigeration circuit.

[0064] The compressor 110 is configured to inhale the low-temperature, low-pressure gaseous refrigerant discharged from the evaporator 140 and compress the low-temperature, low-pressure gaseous refrigerant into a high-temperature, high-pressure gaseous refrigerant; the condenser 120 is configured to dissipate heat and condense the high-temperature, high-pressure gaseous refrigerant discharged from the compressor 110 into a low-temperature, high-pressure liquid refrigerant; the first throttling element 130 is configured to reduce the pressure of the low-temperature, high-pressure liquid refrigerant discharged from the condenser 120 into a low-temperature, low-pressure liquid refrigerant; the evaporator 140 is configured to absorb heat and evaporate the low-temperature, low-pressure liquid refrigerant discharged from the first throttling element 130 into a low-temperature, low-pressure gaseous refrigerant.

[0065] The refrigeration system 100 may further include a gas-liquid separator 150 . The gas-liquid separator 150 may be connected in series between the evaporator 140 and the compressor 110 to separate and store the liquid refrigerant generated by the evaporator 140 .

[0066] The refrigeration system 100 may further include a gas supply device for supplying gaseous refrigerant to the compressor 110 .

[0067] In some embodiments, the air supply device may include a second throttling element 160 , an air supply tank 170 , and a solenoid valve 180 .

[0068] The second throttling element 160 and the air supply tank 170 can be connected to the compressor 110 and the condenser 120 in sequence to form an air supply circuit, so that the high-pressure liquid refrigerant output by the condenser 120 is reduced to a medium-pressure state through the second throttling element 160, and then enters the air supply tank 170. Due to the sudden drop in pressure, it partially evaporates into a gas state and is used to supplement the compressor 110.

[0069] The solenoid valve 180 may be connected in series between the condenser 120 and the second throttling element 160 to open and close the air supply circuit, so as to supply the gaseous refrigerant to the compressor 110 when the air supply circuit is opened.

[0070] The pipeline between the condenser 120 and the first throttling element 130 and the pipeline between the second throttling element 160 and the air supply tank 170 form an economizer 190 through heat exchange to improve system operation efficiency and save energy.

[0071] The compressor 110 may generally include a housing 111, a motor 112, a crankshaft 113, a main bearing 114, a secondary bearing 115, and at least one cylinder. In the present invention, at least one means one, two, or more than two.

[0072] The motor 112 , the crankshaft 113 , the main bearing 114 , the auxiliary bearing 115 , and the cylinder may all be disposed within the housing 111 . The cylinder is configured to communicate with the gas-liquid separator 150 , and the housing 111 is configured to communicate with the condenser 120 .

[0073] The motor 112 may include a stator 112 a and a rotor 112 b rotatably connected to the stator 112 a. The stator 112 a is fixedly connected to the housing 111, and the crankshaft 113 is fixedly connected to the rotor 112 b to rotate under the drive of the motor 112.

[0074] Each cylinder is slidably connected to a sliding plate for dividing the inner space of the cylinder into an air intake chamber and an air discharge chamber.

[0075] The crankshaft 113 may include at least one eccentric portion, each eccentric portion may be sleeved with a piston, and the piston may be configured to contact or connect with the slide, so as to change the size of the intake chamber and the exhaust chamber under the drive of the crankshaft 113 to achieve intake and exhaust of the corresponding cylinder.

[0076] The main bearing 114 may be disposed between the motor 112 and the cylinder, and the secondary bearing 115 may be disposed on a side of the cylinder away from the main bearing 114 .

[0077] Figure 2 yes Figure 1 A schematic top view of the valve assembly 200; Figure 3 It is along Figure 2 Schematic cross-sectional view taken along the cutting line AA in FIG. Figure 2 and Figure 3 The compressor 110 may further include an air supply valve assembly 200 for communicating with the air supply tank 170 to supply gaseous refrigerant to the cylinder.

[0078] The air supply valve assembly 200 includes a mounting member 210 and at least one valve plate 220. The mounting member 210 may be formed with an air supply channel 211 communicating with the air supply tank 170 and at least one air outlet 212 for the gaseous refrigerant to flow out.

[0079] Figure 4 yes Figure 3 Schematic top view of the middle valve plate 220. Figure 3 and Figure 4 Each valve plate 220 includes a tail portion 221 fixedly connected to the mounting member 210, a head portion 222 for opening and closing a gas outlet 212, and a connecting portion 223 connecting the head portion 222 and the tail portion 221. When the piston is in the intake state, the head portion 222 automatically opens the gas outlet 212 under the action of air pressure; when the piston is in the exhaust state, the head portion 222 automatically returns to close the gas outlet 212. The tail portion 221 is fixedly connected to the mounting member 210 via a fastener 240.

[0080] The air outlet 212 may be circular, for example, a perfect circle, an ellipse, or other arc-shaped structures.

[0081] In some embodiments, the head 222 may be polygonal, for example, a quadrilateral, a pentagon, or a hexagon.

[0082] The present invention uses the head 222 of the polygonal valve plate 220 to close the circular air outlet 212, which can ensure the sealing of the valve plate 220 and the rigidity of the head 222, while reducing the vacuum negative pressure formed on the mounting part 210 due to the overlap of the head 222 of the valve plate 220 and the periphery of the air outlet 212, thereby reducing the air replenishment pressure loss.

[0083] In some further embodiments, the number of sides of the head 222 may be greater than or equal to 5, that is, it is at least a pentagon.

[0084] In the present invention, the head 222 of the valve plate 220 is configured as a polygon with 5 or more sides. The sharp corners of the polygon can increase the rigidity of the head 222 and reduce deformation, thereby increasing the service life of the valve plate 220 .

[0085] In some further embodiments, the shortest distance between the corner vertex of the head 222 projected on the opening plane of the air outlet 212 and the edge of the air outlet 212 may be 0.8 mm to 1.6 mm (millimeter), for example, 0.8 mm, 1 mm, 1.2 mm, 1.4 mm, or 1.6 mm.

[0086] The present invention sets the angular vertex of the head 222 of the valve plate 220 to be within the range of 0.8mm to 1.6mm protruding from the air outlet 212. Compared with the circular head 222 of the valve plate 220 protruding more than 3mm from the air outlet 212 in the prior art, the area of ​​negative pressure formed between the head 222 of the valve plate 220 and the periphery of the air outlet 212 can be effectively reduced while ensuring sealing, thereby effectively reducing the loss of air supply pressure.

[0087] In some further embodiments, the opening diameter of the air outlet 212 may be 2.5 mm to 4 mm, for example, 2.5 mm, 3 mm, 3.5 mm, or 4 mm.

[0088] The present invention sets the opening diameter of the air outlet 212 within the range of 2.5mm to 4mm, which can obtain a suitable air supply speed, reduce the refrigerant flow resistance, reduce the noise of the valve plate 220, maintain the stable operation of the refrigeration system 100, and can also cooperate with the head 222 of the polygonal valve plate 220 of a specific size of the present invention to achieve the optimal configuration of comprehensive sealing, structural strength and air supply volume.

[0089] Figure 5 yes Figure 3 A schematic top view of the middle limit baffle 230; Figure 6 yes Figure 5 A schematic side view of the limit stop 230 is shown. Figure 3 、 Figure 5 and Figure 6 In some embodiments, the valve assembly 200 may further include at least one limiting stopper 230 .

[0090] Each stopper 230 can be disposed on a side of a valve disc 220 away from the mounting member 210, fixed to the mounting member 210, and includes a free-end stopper 231 for limiting the lift of a head 222. The stopper 230 and the valve disc 220 can be fixed to the mounting member 210 using a common fastener 240.

[0091] The present invention provides the valve plate 220 with a limit baffle 230 that limits the lift of the head 222, which can control the movement trajectory of the valve plate 220 and accurately control the air supply flow, avoid problems such as tilting and collision of the valve plate 220, and improve the opening and closing response speed and sealing reliability of the valve plate 220.

[0092] The mounting member 210 may be formed with at least one mounting groove, and the bottom wall of each mounting groove may be formed with an air outlet 212. The limiting baffle 230 may be substantially embedded in the mounting groove to improve the structural compactness of the valve assembly 200.

[0093] In some further embodiments, the limiting portion 231 may be circular.

[0094] The present invention sets the limiting portion 231 of the limiting baffle 230 to be circular, which is beneficial to reducing the viscosity problem of the lubricating oil between the head 222 of the polygonal valve plate 220 and the limiting portion 231, ensuring the response speed of the valve plate 220, and avoiding sealing failure of the valve plate 220.

[0095] In some further embodiments, the center of the limiting portion 231 may be closer to the tail portion 221 than the center of the air outlet 212. That is, the vertical distance between the central axis of the fastener 240 and the center of the air outlet 212 is L1, and the vertical distance between the central axis of the fastener 240 and the center of the limiting portion 231 is L2, where L1 is greater than L2.

[0096] The present invention sets the center of the limiting portion 231 between the center of the air outlet 212 and the tail portion 221, which can reduce the flow resistance of the gaseous refrigerant when the head portion 222 of the valve plate 220 is in the open state, thereby improving the gas replenishment efficiency.

[0097] In some further embodiments, the surface of the limiting baffle 230 facing away from the air outlet 212 may be a plane parallel to the opening of the air outlet 212 .

[0098] The surface of the limiting baffle 230 away from the mounting piece 210 is arranged as a plane parallel to the opening of the air outlet 212, which can reduce the space occupied by the limiting baffle 230 in the compressor 110, improve the structural compactness of the compressor 110, and facilitate the machining and positioning of the limiting baffle 230.

[0099] In some further embodiments, the surface of the limiting baffle 230 close to the air outlet 212 can include a circular arc surface corresponding to the connecting portion 223 and the head portion 222, which is arranged to extend away from the mounting piece 210 from the connecting portion 223 to the head portion 222.

[0100] The surface of the limiting baffle 230 at least corresponding to the connecting portion 223 and the head portion 222 of the valve plate 220 is arranged as a circular arc surface, which can realize the flexible contact between the valve plate 220 and the limiting baffle 230 during opening, reduce the noise of the valve plate 220, and form a streamlined refrigerant flow path.

[0101] The surface of the limiting baffle 230 opposite to the tail portion 221 can be a plane parallel to the mounting piece 210, so as to facilitate the installation and positioning of the limiting baffle 230.

[0102] In some further embodiments, the projection of the limiting portion 231 on the plane of the opening of the air outlet 212 can completely cover the head portion 222.

[0103] The limiting portion 231 of the limiting baffle 230 is arranged to project completely covering the head portion 222, which not only can effectively prevent the valve plate 220 from being opened excessively, but also can form a rigid barrier for the air outlet 212 when the valve plate 220 is in a closed state, avoiding the backflow of refrigerant and the accumulation of lubricating oil at the air outlet 212.

[0104] In some further embodiments, the limiting portion 231 can be arranged such that the lift H of the head portion 222 from closing the air outlet 212 to opening the air outlet 212 is 0.8mm-1.2mm. For example, 0.8mm, 0.9mm, 1mm, 1.1mm or 1.2mm. The lift H is the distance between the center of the air outlet 212 and the limiting surface of the limiting baffle 230 in the direction perpendicular to the air outlet 212.

[0105] The lift of the valve plate 220 from the closed state to the open state is limited to the range of 0.8mm-1.2mm, which can balance the refrigerant flow resistance and the closing speed of the valve plate 220, and realize the optimization of the air charge amount.

[0106] In some embodiments, the number of cylinders can be two, which are the first cylinder 116 and the second cylinder 117. The mounting piece 210 can be arranged between the first cylinder 116 and the second cylinder 117 as a partition plate separating the first cylinder 116 and the second cylinder 117.

[0107] The number of each of the air outlet 212 , the valve plate 220 and the limiting baffle 230 may be two. The openings of the two air outlets 212 may face the first cylinder 116 and the second cylinder 117 respectively.

[0108] The supplementary air channel 211 may partially penetrate the mounting member 210 in the thickness direction of the mounting member 210 , so as to directly form two coaxial air outlets 212 at both ends of the supplementary air channel 211 .

[0109] The present invention uses the valve assembly 200 as a partition between the two cylinders to supply air to the two cylinders respectively, reducing the number of parts, realizing structural integration and space optimization, facilitating modular assembly, and reducing the production cost of the compressor 110. Moreover, when the air supply circuit is connected, the two valve plates 220 can be opened and closed alternately with the movement of the piston, and the flow rate of the gaseous refrigerant is stable, thereby improving the operating reliability of the compressor 110.

[0110] Of course, it will be understood by those skilled in the art that the valve assembly 200 of the present invention may also be used as an exhaust valve for exhausting the air from the cylinder to the interior of the housing 111 of the compressor 110 , and the cylinder may be used as the mounting member 210 .

[0111] Figure 7 FIG is a schematic structural diagram of a control circuit according to an embodiment of the present invention. Figure 1 and Figure 7 The refrigeration system 100 may further include a controller 310. The controller 310 may include a processing unit 311 and a storage unit 312. The storage unit 312 stores a computer program 313, which is used to implement the control method of the embodiment of the present invention when executed by the processing unit 311.

[0112] In some embodiments, processing unit 311 may be configured to, upon receiving a power-on command to start compressor 110, obtain the temperature of compressor 110 and, if the temperature of compressor 110 is less than or equal to a preset temperature threshold, input a preset heating voltage to compressor 110 to heat the windings of motor 112 of compressor 110 and thereby heat compressor 110; and, if the temperature of compressor 110 is greater than the preset temperature threshold, input a preset starting voltage to compressor 110 to start compressor 110 normally. For example, the preset heating voltage may be less than or equal to 12V (volts); the preset temperature threshold may be 25°C (Celsius); and both stator 112a and rotor 112b of motor 112 may be provided with windings.

[0113] After receiving the start-up command of the compressor 110, the refrigeration system 100 of the present invention first heats the winding of the motor 112 to heat up the compressor 110 and then starts the compressor 110 normally when the temperature of the compressor 110 is relatively low. This not only has high heating efficiency, but also can avoid the problem of excessive load on the motor 112 and aggravated wear of moving parts such as bearings and pistons caused by the lubricating oil being discharged from the compressor 110 along with the refrigerant due to low temperature. In addition, it can prevent the opening and closing of the air supply valve plate 220 from being delayed or stuck, or even the valve plate 220 from malfunctioning (such as sealing failure, blockage of the air supply channel 211), reducing fatigue damage to the valve plate 220, avoiding undesirable increase in system energy efficiency, and enabling the system to adapt to complex working conditions.

[0114] In some further embodiments, the refrigeration system 100 may further include a temperature sensor 320 disposed at the bottom of the compressor 110 for sensing the temperature at a location corresponding to the bottom oil pool of the housing 111 of the compressor 110. The temperature of the compressor 110 used to determine whether to preheat the compressor 110 may be the temperature at a location corresponding to the bottom oil pool of the housing 111 of the compressor 110.

[0115] The present invention uses the temperature of the bottom of the casing 111 of the compressor 110 to determine whether the compressor 110 needs to be preheated, which can accurately evaluate the impact of the lubricating oil state on the operation of the compressor 110 and improve the starting speed of the compressor 110.

[0116] In some further embodiments, after the compressor 110 is started normally, the processing unit 311 may also be configured to determine whether the compressor 110 is overloaded, and control the air replenishing device to replenish the gaseous refrigerant to the compressor 110 when the compressor 110 is overloaded.

[0117] The present invention replenishes gaseous refrigerant to the compressor 110 when the compressor 110 is overloaded. By adjusting the refrigerant flow rate, the circulation lubrication effect of the lubricating oil can be improved, the temperature of the motor 112 can be reduced, the circulation efficiency can be optimized, and the service life and safety performance of the refrigeration system 100 can be improved.

[0118] In some further embodiments, the processing unit 311 may be further configured to determine whether the compressor 110 is overloaded based on the operating frequency of the compressor 110. Specifically, the processing unit 311 may be configured to determine whether the operating frequency of the compressor 110 is greater than or equal to a preset frequency threshold, and if so, determine that the compressor 110 is overloaded. For example, the preset frequency threshold may be 30 Hz (Hertz).

[0119] The present invention determines whether the compressor 110 needs to be supplemented with gaseous refrigerant based on the frequency of the compressor 110, and can realize real-time judgment of the workload without adding additional sensors. The hardware cost is low and the control logic is simple.

[0120] In some further embodiments, the refrigeration system 100 may further include a discharge pressure sensor 330 and a suction pressure sensor 340 for respectively sensing the discharge pressure and suction pressure of the compressor 110 .

[0121] The processing unit 311 may also be configured to determine whether the compressor 110 is overloaded based on the ratio of the discharge pressure to the suction pressure of the compressor 110. Specifically, the processing unit 311 may be configured to determine whether the ratio of the discharge pressure to the suction pressure of the compressor 110 is greater than or equal to a preset pressure ratio threshold. If so, the compressor 110 is determined to be overloaded. For example, the preset pressure ratio threshold may be 3.

[0122] The present invention determines whether it is necessary to supplement the gaseous refrigerant to the compressor 110 based on the ratio of the exhaust pressure to the suction pressure of the compressor 110, which can more directly reflect the workload of the compressor 110 and avoid control failure due to abnormal electrical parameters.

[0123] In some further embodiments, the processing unit 311 may be further configured to determine whether the compressor 110 is overloaded based on the operating frequency of the compressor 110 and the ratio of the discharge pressure to the suction pressure of the compressor 110. That is, the compressor 110 is determined to be overloaded when either the operating frequency is greater than or equal to a preset frequency threshold, or the ratio of the discharge pressure to the suction pressure is greater than or equal to a preset pressure ratio threshold, in order to balance response speed and control reliability.

[0124] Figure 8 is a schematic flow chart of a control method for a refrigeration system 100 according to an embodiment of the present invention. Figure 8 The control method for the refrigeration system 100 of the present invention may include the following steps:

[0125] Step S802: receiving a start-up instruction for starting the compressor 110 and obtaining the temperature of the compressor 110;

[0126] Step S804: when the temperature of the compressor 110 is less than or equal to a preset temperature threshold, input a preset heating voltage to the compressor 110 to heat the winding of the motor 112 of the compressor 110 to heat the compressor 110;

[0127] Step S806 : When the temperature of the compressor 110 is greater than the preset temperature threshold, a preset starting voltage is input to the compressor 110 so that the compressor 110 starts normally.

[0128] After receiving the start-up command of the compressor 110, the control method of the present invention first heats the winding of the motor 112 to heat up the compressor 110 and then starts the compressor 110 normally when the temperature of the compressor 110 is relatively low. This not only has high heating efficiency, but also can avoid the problem of excessive load on the motor 112 and aggravated wear of moving parts such as bearings and pistons caused by the lubricating oil being discharged from the compressor 110 along with the refrigerant due to low temperature. In addition, it can prevent the opening and closing of the air supply valve plate 220 from being delayed or stuck, or even failure of the valve plate 220 (such as sealing failure, blockage of the air supply channel 211), reduce fatigue damage of the valve plate 220, avoid undesirable increase in system energy efficiency, and enable the system to adapt to complex working conditions.

[0129] The control strategy of the present invention combined with the one-way air supply valve plate 220 can reduce the wear of the valve plate 220 and avoid the failure of the sealing performance of the valve plate 220 causing air supply abnormalities, reduce the requirements for the overlapping area between the valve plate 220 and the periphery of the air outlet 212, and can reduce the size of the head 222 of the valve plate 220 while ensuring the reliability of the operation of the compressor 110.

[0130] In some embodiments, in step S802 , the temperature of the compressor 110 may be the temperature of the position of the casing 111 of the compressor 110 corresponding to the bottom oil pool, so as to accurately evaluate the impact of the lubricating oil state on the operation of the compressor 110 and improve the starting speed of the compressor 110 .

[0131] In some embodiments, after step S806, the method further includes:

[0132] Step S808: determining whether the compressor 110 is overloaded;

[0133] Step S810 : When the compressor 110 is overloaded, the gas supply device is controlled to supply gaseous refrigerant to the compressor 110 .

[0134] The present invention replenishes gaseous refrigerant to the compressor 110 when the compressor 110 is overloaded. By adjusting the refrigerant flow rate, the circulation lubrication effect of the lubricating oil can be improved, the temperature of the motor 112 can be reduced, the circulation efficiency can be optimized, and the service life and safety performance of the refrigeration system 100 can be improved.

[0135] In some further embodiments, step S808 may include:

[0136] It is determined whether the operating frequency of the compressor 110 is greater than or equal to a preset frequency threshold. If so, it is determined that the compressor 110 is overloaded.

[0137] The present invention determines whether the compressor 110 needs to be supplemented with gaseous refrigerant based on the frequency of the compressor 110, and can realize real-time judgment of the workload without adding additional sensors. The hardware cost is low and the control logic is simple.

[0138] In some further embodiments, step S808 may include:

[0139] It is determined whether the ratio of the exhaust pressure to the suction pressure of the compressor 110 is greater than or equal to a preset pressure ratio threshold. If so, it is determined that the compressor 110 is overloaded.

[0140] The present invention determines whether it is necessary to supplement the gaseous refrigerant to the compressor 110 based on the ratio of the exhaust pressure to the suction pressure of the compressor 110, which can more directly reflect the workload of the compressor 110 and avoid control failure due to abnormal electrical parameters.

[0141] In some further embodiments, step S808 may include:

[0142] Determine whether the operating frequency of the compressor 110 is greater than or equal to a preset frequency threshold, or whether the ratio of the exhaust pressure to the suction pressure of the compressor 110 is greater than or equal to a preset pressure ratio threshold. If either condition is true, it is determined that the compressor 110 is overloaded, taking into account both response speed and control reliability.

[0143] At this point, those skilled in the art will recognize that, although a number of exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications consistent with the principles of the present invention may be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should be understood and deemed to cover all such other variations or modifications.

Claims

1. A control method for a refrigeration system, wherein the refrigeration system includes a compressor, the control method comprising: receiving a start-up instruction for starting the compressor and obtaining the temperature of the compressor; When the temperature of the compressor is less than or equal to a preset temperature threshold, inputting a preset heating voltage to the compressor so as to heat the motor winding of the compressor; When the temperature of the compressor is greater than the preset temperature threshold, a preset starting voltage is input to the compressor so that the compressor starts normally.

2. The control method according to claim 1, wherein: The temperature of the compressor is the temperature of a position of the compressor casing corresponding to the bottom oil pool.

3. The control method according to claim 1, wherein the refrigeration system further comprises an air supply device, and the control method further comprises, after the step of normally starting the compressor: Determining whether the compressor is overloaded; When the compressor is overloaded, the air supply device is controlled to supply gaseous refrigerant to the compressor.

4. The control method according to claim 3, wherein the step of determining whether the compressor is overloaded comprises: It is determined whether the operating frequency of the compressor is greater than or equal to a preset frequency threshold. If so, it is determined that the compressor is overloaded.

5. The control method according to claim 3, wherein the step of determining whether the compressor is overloaded comprises: It is determined whether the ratio of the exhaust pressure to the suction pressure of the compressor is greater than or equal to a preset pressure ratio threshold. If so, it is determined that the compressor is overloaded.

6. A refrigeration system comprising: The compressor, the condenser, the first throttling element and the evaporator are connected in sequence to form a refrigeration circuit; an air supply device for supplying gaseous refrigerant to the compressor; as well as A controller configured to execute the control method according to any one of claims 1 to 5.

7. The refrigeration system according to claim 6, wherein: The air replenishing device comprises: A second throttling element and an air supply tank are connected in sequence with the compressor and the condenser to form an air supply circuit, and The solenoid valve is connected in series between the condenser and the second throttling element, and is used to open and close the air supply circuit so as to supply gaseous refrigerant to the compressor when the air supply circuit is opened.

8. The refrigeration system according to claim 6, wherein: The compressor further includes an air supply valve assembly, which includes: The mounting member is formed with at least one gas outlet for the gaseous refrigerant to flow out; and At least one valve plate, each valve plate includes a tail portion fixedly connected to the mounting member, a head portion for opening and closing one of the air outlets, and a connecting portion connecting the head portion and the tail portion.

9. The refrigeration system according to claim 8, wherein: The air outlet is circular; and The head is polygonal, with the number of sides being greater than or equal to 5.

10. The refrigeration system according to claim 9, wherein: The shortest distance between the vertex of the corner projected by the head on the opening plane of the air outlet and the edge of the air outlet is 0.8 mm to 1.6 m.

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