A high-power stirling refrigerator for a refrigerator and a refrigerator

Abstract

The application discloses a high-power Stirling refrigerator for a refrigerator and the refrigerator, which comprises a shell assembly, a cylinder assembly arranged in the shell assembly, a piston assembly, and a linear motor; the cylinder assembly comprises an integrated cylinder, the piston assembly comprises a power piston mechanism, and the power piston mechanism comprises a power piston; the linear motor comprises, from inside to outside along its radial direction, an inner magnetic yoke, a magnetic ring, and an outer magnetic yoke, the outer magnetic yoke is provided with a recess facing the magnetic ring, the recess is used for winding a coil, a magnetic ring support is arranged at the lower end of the magnetic ring, the magnetic ring support is connected with the power piston, when the coil is electrified and interacts with the magnetic ring, the linear reciprocating motion of the magnetic ring drives the magnetic ring support to linearly reciprocate, and then drives the power piston to linearly reciprocate in the integrated cylinder. The refrigerator is optimized in the structural level and the control level, so that the overall efficiency is improved, the vibration and noise are reduced, and high-efficiency operation in a wide working condition range is realized.

Description

Technical Field

[0001] This application relates to the field of refrigeration technology, and in particular to a high-power Stirling refrigerator and a refrigerator for use in refrigerators. Background Technology

[0002] A Stirling refrigerator is a device that uses the periodic compression and expansion of a gas to achieve refrigeration. It boasts advantages such as high theoretical efficiency, the ability to use inert gases as working fluids, and environmental friendliness. In recent years, with the development of low-temperature refrigerators, medical cold chains, and high-end household appliances, the demand for Stirling refrigerators in small-scale, high-efficiency refrigeration applications has been continuously increasing.

[0003] However, applying Stirling refrigerators to refrigeration systems still faces several technical bottlenecks in the current technology. First, traditional Stirling refrigerators mostly employ a rotary motor-crank-connecting rod structure, which suffers from high mechanical friction, limited reliability, and difficulty in further improving efficiency. Second, in existing linear drive Stirling refrigerators, the linear motor structure and Stirling mechanism components are not well-matched, resulting in low electromagnetic efficiency and large high-order vibration components of the mover, thus causing noise and vibration problems in the entire machine. Third, under partial load conditions (i.e., most of the time the refrigerator operates stably), the drive frequency deviates from the system's natural frequency, causing increased input power and decreased refrigeration efficiency.

[0004] Therefore, there is an urgent need in the field to develop a high-power Stirling refrigerator for refrigerators that improves overall efficiency, reduces vibration and noise, and achieves efficient operation over a wide range of operating conditions through synergistic optimization at both the structural and control levels. Summary of the Invention

[0005] The purpose of this application is to provide a high-power Stirling refrigerator for refrigerators, which improves overall efficiency, reduces vibration and noise, and achieves efficient operation over a wide range of operating conditions through synergistic optimization at both the structural and control levels.

[0006] This application provides a high-power Stirling refrigerator for refrigerators, including: a housing assembly, a cylinder assembly, a piston assembly, and a linear motor disposed within the housing assembly;

[0007] The cylinder assembly includes an integrated cylinder, and the piston assembly includes a power piston mechanism, which includes a power piston.

[0008] The linear motor includes, from the inside to the outside, an inner magnetic yoke, a magnetic ring, and an outer magnetic yoke in its radial direction. The outer magnetic yoke has a recess facing the magnetic ring, which is used to wind a coil. A magnetic ring support frame is provided at the lower end of the magnetic ring. The magnetic ring support frame is connected to the power piston. When the energized coil interacts with the magnetic ring, the linear reciprocating motion of the magnetic ring drives the magnetic ring support frame to perform linear reciprocating motion, thereby driving the power piston to perform linear reciprocating motion within the integrated cylinder.

[0009] In another preferred embodiment, the coil is wound with flat wire, thereby increasing the number of turns of the coil within the limited space of the recess, thus improving motor efficiency. In another preferred embodiment, the power piston mechanism further includes a power leaf spring, which is connected to the magnetic ring support frame via a first connector.

[0010] In another preferred embodiment, the power leaf spring, the magnetic ring support frame, and the power piston are fixedly connected by the first connecting member.

[0011] In another preferred embodiment, the first connecting member is a power piston fixing screw, and the number of power piston fixing screws is 1, which is a ring-shaped screw.

[0012] In another preferred embodiment, the power piston is an annular component, the power piston includes a central cavity, and the piston assembly further includes a discharge piston mechanism, the discharge piston mechanism includes a first discharge piston and a discharge piston connecting rod, in the axial direction of the discharge piston connecting rod, the discharge piston connecting rod sequentially passes through the power leaf spring, the magnetic ring support frame, the central cavity of the power piston and the compression chamber of the Trin refrigerator, and is connected to the first discharge piston.

[0013] In another preferred embodiment, the discharge piston mechanism further includes a discharge leaf spring disposed at the end of the discharge leaf spring opposite to the discharge piston.

[0014] In another preferred embodiment, the discharge piston mechanism further includes a second discharge piston, the cylinder assembly further includes a discharge cylinder, the discharge cylinder is threadedly connected to the integral cylinder, the second discharge piston is threadedly connected to the first discharge piston, the second discharge piston reciprocates within the discharge cylinder under the drive of the discharge piston connecting rod, and the discharge cylinder is a non-metallic component.

[0015] Preferably, the second discharge piston is made of plastic, and the first discharge piston is made of metal.

[0016] In another preferred embodiment, the cylinder assembly consists of an integral cylinder and an exhaust cylinder.

[0017] In another preferred embodiment, the magnetic ring support frame includes a first connecting portion and a second connecting portion. The first connecting portion is annular and substantially perpendicular to the second connecting portion. The first connecting portion is connected to the lower end of the magnetic ring, and the upper surface of the second connecting portion is connected to the lower surface of the power piston.

[0018] In another preferred embodiment, the discharge piston connecting rod passes through the second connecting portion and leaves a certain gap between it and the second connecting portion.

[0019] In another preferred embodiment, in the radial direction, a portion of the first connecting portion is located between the inner yoke and the outer yoke.

[0020] In another preferred embodiment, the housing assembly is further provided with a motor fixing structure, which includes a soft magnetic fixing frame. The upper end face of the soft magnetic fixing frame is connected to the outer magnetic yoke, and the lower end face of the soft magnetic fixing frame is connected to the power leaf spring.

[0021] Preferably, in the radial direction, the soft magnetic fixing frame is located outside the magnetic ring support frame.

[0022] Preferably, the motor fixing structure further includes an inner magnetic yoke fixing aluminum ring, which is located below the inner magnetic yoke.

[0023] In another preferred embodiment, a cold finger assembly is further included, coaxially disposed on the upper end of the housing assembly. The cold finger assembly includes a cold finger base and a hot end heat sink, the hot end heat sink being located above the cold finger base, and the integrated cylinder being connected to the cold finger base.

[0024] In another preferred embodiment, the integrated cylinder is machined with an annular groove for the flow of gas in the compression chamber.

[0025] In another preferred embodiment, the cold finger assembly further includes a hot-end copper chain, a regenerator, a cold-end copper chain arranged sequentially along the axial direction, a regenerator housing disposed outside the regenerator in the radial direction, and a cold-end heat exchanger and a cold cap. Preferably, the cold-end heat exchanger is sleeved outside the cold-end copper chain and the regenerator housing.

[0026] In another preferred embodiment, the integrated cylinder includes a first cylinder sub-section, a second cylinder sub-section, and a third cylinder sub-section. In the radial direction, the first cylinder sub-section is located between the power piston and the inner magnetic yoke, and the second cylinder sub-section is connected to the cold finger base.

[0027] Preferably, the first discharge piston reciprocates within the third cylinder sub-section.

[0028] In another preferred embodiment, the housing assembly includes a lower housing, which includes an annular housing portion and a bottom-closed housing portion. The bottom-closed housing portion protrudes outward toward the outside of the housing assembly. The annular housing portion is disposed outside the outer magnetic yoke in the radial direction. The upper end of the annular housing is connected to the cold finger base.

[0029] In another preferred embodiment, an electrical interface is provided at the lower part of the annular housing portion for the electrodes to pass through, thereby connecting an external power source to an internal coil.

[0030] In another preferred embodiment, the lower housing is presented as an approximately bell-shaped or bowl-shaped structure with an open top and a closed bottom.

[0031] In another preferred embodiment, the housing assembly includes a lower housing, which includes an annular housing portion and a bottom closed housing portion. The Stirling refrigerator also includes a shock-absorbing assembly disposed outside the housing assembly, the shock-absorbing assembly including shock-absorbing stator fixing screws connected to the bottom closed housing portion.

[0032] In another preferred embodiment, the damping assembly further includes a damper fixing nut, a damper counterweight, a damper fixing washer, a damper fixing screw and a damper stator fixing nut, and a damper plate spring.

[0033] A second aspect of this application provides a refrigerator comprising the aforementioned Stirling refrigeration unit, the refrigerator including a controller configured to perform frequency conversion and voltage conversion drive control on the linear motor.

[0034] A third aspect of this application provides a control method for controlling the operation of the refrigerator, comprising the following steps:

[0035] The controller drives the linear motor of the Stirling refrigerator to move with a preset initial excitation voltage and excitation frequency, so that the Stirling refrigerator starts up and enters the refrigeration state.

[0036] If the internal temperature of the refrigerator does not reach the target temperature, the controller is configured to increase the excitation voltage to increase the input power of the Stirling refrigerator.

[0037] During the process of increasing the excitation voltage, the stroke of the power piston of the Stirling refrigerator is monitored in real time, and the excitation voltage is adjusted in a closed loop so that the stroke of the power piston is always at a set value, which is any value between 1mm and 15mm.

[0038] Once the temperature inside the refrigerator reaches the target temperature, the controller is configured to reduce the excitation voltage to decrease the input power of the Stirling refrigerator and the stroke of the power piston until the minimum input power required to maintain the target temperature inside the refrigerator is reached.

[0039] By adjusting the excitation voltage and excitation frequency within a small range, the optimal operating point corresponding to the minimum input power required to maintain the target temperature inside the chamber is found, and operation is maintained at that operating point.

[0040] It should be understood that, within the scope of this invention, the above-described technical features of this invention and the technical features specifically described below (such as in the embodiments) can be combined with each other to form new or preferred technical solutions. Due to space limitations, they will not be described in detail here. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. It should be understood that the accompanying drawings described below are merely some implementation examples of the present invention, and those skilled in the art can obtain other implementation examples based on these drawings without creative effort.

[0042] Figure 1 This is a schematic diagram of the overall structure of a high-power Stirling refrigerator for refrigerators according to this application;

[0043] Figure 2 This is a schematic diagram of the magnet-embedded linear motor of the Stirling refrigerator according to the first embodiment of this application;

[0044] Figure 3 The current waveform (with built-in magnet) of the linear motor with built-in magnet obtained by simulation calculation according to the first embodiment of this application when it reaches a specified stroke.

[0045] Figure 4 The components of the fundamental frequency and high-order frequency current of the magnet-embedded linear motor (embedded magnet) are obtained by simulation calculation according to the first embodiment of this application.

[0046] Figure 5 This is a schematic diagram of a linear motor with an external magnet according to the first comparative embodiment;

[0047] Figure 6 The current waveform of the external magnet linear motor when it reaches a specified stroke is obtained by simulation calculation according to the first comparative embodiment.

[0048] Figure 7 The components of the fundamental frequency and high-order frequency current of the external magnet linear motor are obtained by simulation calculation based on the first comparative embodiment.

[0049] Figure 8 This is a flowchart of the drive control logic for a Stirling refrigeration unit used in refrigerators;

[0050] Figure 9 A schematic diagram of the structure of the power piston fixing screw for a high-power Stirling refrigerator according to this application is shown.

[0051] In each of the attached figures, the markings are as follows:

[0052] 1-Cold cap; 2-Cold end heat exchanger; 3-Discharge cylinder; 4-Regenerator shell; 5-Second discharge piston; 6-Hot end copper chain; 7-Hot end radiator; 8-Cold finger base;

[0053] 9-Lower shell; 91-Annular shell section; 92-Bottom closed shell section

[0054] 10-Coil; 11-Outer yoke; 12-Electrode; 13-Soft magnetic mounting bracket; 14-Electrode welding housing; 15-Sterile stator fixing screw; 16-Sterile damper fixing nut; 17-Sterile damper counterweight; 18-Sterile damper fixing washer; 19-Sterile damper fixing screw; 20-Sterile damper stator fixing nut; 21-Sterile damper leaf spring; 22-Discharge leaf spring; 23-Leaf spring support column; 24-Power leaf spring; 25-Power piston fixing screw;

[0055] 26-Magnetic ring support frame; 261-First connecting part; 262-Second connecting part;

[0056] 27-Inner magnetic yoke fixing aluminum ring; 28-Inner magnetic yoke; 29-Magnetic ring; 30-Power piston; 31-Connecting rod; 32-Cylinder; 33-First discharge piston; 34-Regenerator; 35-Cold end copper chain. Detailed Implementation

[0057] Through extensive and in-depth research, a high-power Stirling refrigerator for refrigerators has been developed for the first time. This high-power Stirling refrigerator significantly reduces the high-order frequency components of the motor current by incorporating a linear motor with built-in magnets, thereby reducing high-order vibration and noise of the refrigerator and improving operational stability. Furthermore, the cylinder seat and cylinder are integrated into one unit and manufactured using the same material. This unit serves both as a mechanical connection for the cylinder seat and as a seal and wear-resistant material for the cylinder clearance, significantly reducing processing costs and procedures and facilitating mass production.

[0058] In the following description, many technical details are presented to help the reader better understand this application. However, those skilled in the art will understand that the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0059] the term

[0060] As used herein, the terms “axial” and “axial direction” are used interchangeably, as are the terms “radial” and “radial direction”.

[0061] As used herein, the terms “linear motor assembly” and “linear motor” are used interchangeably;

[0062] As used herein, the terms “excitation frequency” and “drive frequency” are used interchangeably;

[0063] As used herein, the terms “excitation voltage” and “drive voltage” are used interchangeably;

[0064] In this invention, all directional indicators (such as up, down, left, right, front, back, etc.) are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0065] This application has at least one of the following advantages:

[0066] (a) This application enables the refrigeration machine to operate at its highest efficiency point under different refrigeration temperatures and refrigeration capacity requirements through frequency conversion and voltage conversion control, thus overcoming the problem of low efficiency of traditional refrigeration machines under partial load.

[0067] (b) The Stirling refrigerator of this application significantly reduces the high-order frequency component of the motor current by setting a linear motor with built-in magnets, thereby reducing the high-order vibration and noise of the refrigerator and improving the operational stability.

[0068] (c) The Stirling refrigerator of this application optimizes the number of turns of the linear motor coil by using flat wire instead of the more commonly used round wire, thereby increasing the number of turns of the coil that can be wound in a limited space and improving the motor efficiency.

[0069] (d) The Stirling refrigerator of this application integrates the cylinder seat and the cylinder into one unit and is made of the same material. It not only undertakes the mechanical connection of the cylinder seat, but also undertakes the functions of sealing the cylinder gap and smooth wear resistance, which significantly reduces the processing cost and process flow and facilitates mass production.

[0070] To make the objectives, technical solutions, and advantages of the present invention clearer, embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. It should be understood that these are merely examples provided to the reader of possible implementations of the present invention and are not intended to limit the scope of the invention.

[0071] Example 1

[0072] A high-power Stirling refrigerator

[0073] See Figure 1 This application provides a high-power Stirling refrigerator for refrigerators. The Stirling refrigerator has an overall axial arrangement structure and mainly includes: a housing assembly, a cylinder assembly, a piston assembly, and a linear motor assembly disposed within the housing assembly, as well as a shock-absorbing assembly disposed outside the housing assembly.

[0074] Linear motor assembly

[0075] The linear motor assembly of the Stirling refrigeration unit in this application is a linear motor with an internal magnet and an external coil.

[0076] The linear motor assembly includes, from the inside to the outside, an inner magnetic yoke 28, a magnetic ring 29, and an outer magnetic yoke 11 along its radial direction. The outer magnetic yoke 11 has a recess facing the magnetic ring 29, which is used to wind the coil 10. A magnetic ring support frame 26 is provided at the lower end of the magnetic ring 29. The magnetic ring support frame 26 is connected to the power piston 30. When the energized coil 10 interacts with the magnetic ring 29, the linear reciprocating motion of the magnetic ring 29 drives the magnetic ring support frame 26 to perform linear reciprocating motion, thereby driving the power piston 30 to perform linear reciprocating motion in the integrated cylinder 32.

[0077] When energized, the alternating current flowing through coil 10 generates an alternating magnetic field. This magnetic field interacts with the magnetic ring 29, causing the magnetic ring 29 and its support frame 26 to reciprocate linearly along the axial direction. This reciprocating motion is then connected to the power piston 30 via the power piston fixing screw 25, driving the power piston 30 to reciprocate within the integrated cylinder 32, compressing the working gas. Simultaneously, the discharge piston, under the influence of the pressure wave in the compression chamber and the discharge leaf spring, maintains a certain phase difference with the power piston, completing the Stirling cycle.

[0078] Since the magnet (magnetic ring 29) is located inside the mover and the coil is fixed on the outer magnetic yoke 11, the high-order electromagnetic force components experienced by the magnetic ring 29 during the movement are significantly reduced, thereby effectively reducing the high-frequency vibration caused by motor excitation.

[0079] The lower end of the magnetic ring 29 is connected to a magnetic ring support frame 26, which is used to transmit the linear motion of the magnetic ring 29 to the piston assembly.

[0080] The magnetic ring support frame 26 includes a first connecting part 261 and a second connecting part 262. The first connecting part 261 is annular and is substantially perpendicular to the second connecting part 262. The first connecting part 261 is connected to the lower end of the magnetic ring 29, and the upper surface of the second connecting part 262 is connected to the lower surface of the power piston 30.

[0081] The coil 10 is wound inside the recess of the outer magnetic yoke 11, forming a winding connection with the outer magnetic yoke 11 to constitute the excitation coil structure of the linear motor.

[0082] Preferably, the magnetic ring support frame 26 and the magnetic ring 29 are fixedly connected by adhesive to ensure the structural stability of the magnetic ring during reciprocating motion.

[0083] The housing assembly also includes a motor fixing structure, which includes a soft magnetic fixing bracket 13. The upper end face of the soft magnetic fixing bracket 13 is connected to the outer magnetic yoke 11, and the lower end face of the soft magnetic fixing bracket 13 is connected to the power leaf spring 24.

[0084] The outer magnetic yoke 11 is also located below the cold finger base 8. The soft magnetic fixing frame 13, the outer magnetic yoke 11 and the cold finger base 8 are connected by screw fixing, so that the motor magnetic circuit structure and the whole frame form an integrated support.

[0085] Preferably, in the radial direction, the soft magnetic fixing frame 13 is located outside the magnetic ring support frame 26.

[0086] Preferably, the motor fixing structure further includes an inner magnetic yoke fixing aluminum ring 27, which is located directly below the inner magnetic yoke 28.

[0087] The inner magnetic yoke 28, the inner magnetic yoke fixing aluminum ring 27, and the integrated cylinder 32 are fixedly connected by adhesive to ensure the stability of the magnetic circuit structure and reduce assembly gaps.

[0088] The magnetic ring support frame 26, the power piston fixing screw 25, and the power piston 30 are connected by threads, thereby reliably transmitting the linear motion of the magnetic ring to the power piston 30.

[0089] Cylinder assembly and piston assembly

[0090] The cylinder assembly and piston assembly are the core components that enable gas compression and expansion.

[0091] The cylinder assembly is housed inside the housing assembly and consists of a one-piece cylinder 32 and an exhaust cylinder 3. The exhaust cylinder 3 is made of plastic, while the one-piece cylinder is made of metal (such as aluminum alloy, titanium alloy, stainless steel, etc.).

[0092] The discharge cylinder 3 is connected to the upper outer side of the integrated cylinder 32 via a threaded connection, facilitating assembly and maintenance. The integrated cylinder 32 has an annular groove machined in it for the flow of gas in the compression chamber.

[0093] The integrated cylinder 32 includes a first cylinder section, a second cylinder section, and a third cylinder section. In the radial direction, the first cylinder section is located between the power piston 30 and the inner magnetic yoke 28, and the second cylinder section is connected to the cold finger base 8. The first discharge piston 33 reciprocates within the third cylinder section.

[0094] The piston assembly includes a power piston mechanism and a discharge piston mechanism. The power piston mechanism includes a power piston 30 and a power leaf spring 24. The power piston 30 is an annular component with a central cavity. It is connected to the power piston 30 via a power piston fixing screw 25, the power leaf spring 24, and the second connecting part 262 of the magnetic ring support frame 26. In the axial direction, the power leaf spring 24 is located below the magnetic ring support frame 26. Preferably, there is one power piston fixing screw, and the power piston screw 25 is annular. The long side of the power piston screw 25 passes through the second connecting part 262 of the magnetic ring support frame 26 and the power piston 30 in sequence. The head of the power piston screw 25 is located below the power leaf spring 24. The discharge piston connecting rod 31 also passes through the power piston screw 25. Figure 9 As shown, a schematic diagram of the structure of the power piston screw 25 is presented.

[0095] The discharge piston mechanism includes a first discharge piston 33, a second discharge piston 5, a discharge piston connecting rod 31, and a discharge leaf spring. In the axial direction of the discharge piston connecting rod 31, the discharge piston connecting rod 31 passes sequentially through the power leaf spring 24, the magnetic ring support frame 26 (the first connecting part 261 of the magnetic ring support frame 26), the central cavity of the power piston 30, and the compression chamber of the Trin refrigerator, and is connected to the first discharge piston 33.

[0096] The discharge leaf spring 22 is located at the end of the discharge leaf spring 22 opposite to the first discharge piston 33.

[0097] The discharge leaf spring 22 is fixed to the soft magnetic bracket 13 by screws and leaf spring support column 23. Its central area is connected to the end of the discharge piston connecting rod 31, providing radial support and axial elastic restoring force for the discharge piston.

[0098] The power leaf spring 24 and the discharge leaf spring 22 are pressed together by screws and leaf spring support column 23. The leaf spring support column 23 is connected to the soft magnetic fixing frame 13 by threads.

[0099] The second discharge piston 5 is threadedly connected to the first discharge piston 33. The second discharge piston 5 reciprocates within the discharge cylinder 3 under the drive of the discharge piston connecting rod 31.

[0100] Preferably, the second discharge piston is made of plastic, and the first discharge piston is made of metal.

[0101] housing assembly

[0102] The housing assembly includes a lower housing 9, which has an approximately bell-shaped or bowl-shaped structure with an open top and a closed bottom. It includes an annular housing portion 91 and a bottom-closed housing portion 92. The bottom-closed housing portion 92 protrudes outward from the housing assembly. The annular housing portion 91 covers the outer side of the outer magnetic yoke 11 in the radial direction, and its upper end is connected to the cold finger base 8. The bottom-closed housing portion 92 is used to install the shock-absorbing components and to protect the internal structure.

[0103] An electrical interface is provided at the lower part of the annular housing portion 91 for the electrode 12 to pass through, so as to connect the external power supply to the internal coil 10.

[0104] The lower housing 9, electrode 12, electrode welding shell 14, and shock-absorbing stator fixing screw 15 are connected by welding to achieve reliable lead-out of electrical interface and structural sealing.

[0105] Cold finger components

[0106] The cooling component is used to achieve the cooling effect and is located at the top of the unit.

[0107] The cold finger assembly includes a cold cap 1, a cold end heat exchanger 2, a cold end copper chain 35, a regenerator 34, a hot end copper chain 6, a hot end radiator 7, and a cold finger base 8 arranged sequentially from top to bottom along the axial direction.

[0108] The regenerator 34 is encased in a regenerator shell 4. The cold-end heat exchanger 2 is fitted over the cold-end copper chain 35 and the regenerator shell 4, and is used to efficiently transfer cooling energy to the cold cap 1. The hot-end radiator 7 is welded and fixed to the cold finger base 8. This structure achieves efficient heat exchange of the working fluid between the hot and cold ends in the Stirling cycle. Specifically, cooling energy is conducted away from the cold head (i.e., the cold-end heat exchanger 2 and the cold cap 1), while heat is conducted through the hot-end copper chain 6 to the hot-end radiator 7 and dissipated into the environment.

[0109] The cold cap 1, cold end heat exchanger 2, regenerator shell 4, hot end radiator 7, and cold finger base 8 are fixedly connected by welding to form a stable and reliable overall structure of the cold finger assembly. The hot end copper chain 6, regenerator 34, and cold end copper chain 35 are arranged sequentially along the axial direction and are connected by compression to ensure good thermal contact.

[0110] shock absorption components

[0111] like Figure 1As shown, the Stirling refrigerator in this embodiment also includes a shock-absorbing assembly disposed outside the housing assembly. The shock-absorbing assembly includes a shock-absorbing stator fixing screw 15, a shock-absorbing stator fixing nut 16, a shock-absorbing stator counterweight 17, a shock-absorbing stator fixing washer 18, a shock-absorbing stator fixing screw 19, a shock-absorbing stator fixing nut 20, and a shock-absorbing leaf spring 21. The shock-absorbing stator fixing screw 15 is connected to the bottom closed housing portion 92.

[0112] One end of the damping leaf spring 21 is fixed to the damping stator fixing screw 15, and the other end is connected to the damping motor counterweight 17. By reasonably matching the counterweight mass and spring stiffness, the natural frequency of the damping component is made close to the excitation frequency of the linear motor, thereby effectively absorbing the fundamental frequency vibration.

[0113] The shock absorber stator fixing screw 15 and the shock absorber stator fixing nut 20 are connected by threads to press the inner ring of the shock absorber spring 21, thereby reliably installing the shock absorber assembly on the lower housing.

[0114] The vibration damper fixing nut 16, vibration damper counterweight 17, vibration damper fixing washer 18, vibration damper fixing screw 19, vibration damper stator fixing nut 20, and vibration damper leaf spring 21 are connected by screw fixing to form a passive vibration damping assembly.

[0115] Example 2

[0116] Stirling refrigerators are typically powered by linear compressors, which are driven by linear motors that make pistons reciprocate. The efficiency of the linear motor determines the efficiency of the compressor and thus the overall cooling performance of the unit.

[0117] In this embodiment, the linear motor with built-in magnet and external coil of this application was simulated. The ANSYS Maxwell module is a professional service for electromagnetic simulation of motors. In Maxwell, a structural model of the motor's internal yoke, magnet, coil, and external yoke was established (the specific dimensions are based on the motor dimensions corresponding to the example of this invention). Then, the materials of each component were assigned (the yoke material is DT4 series, the magnet material is neodymium iron boron, and the coil is copper wire). Next, the motor motion load (such as mover mass, motion damping, spring stiffness, etc.) was assigned, and the motor coil was excited (the number of coil turns, resistance, excitation voltage, and frequency were set, etc.). Finally, the motor boundary conditions, the mesh generation of each component, and the number of motion cycles were set. Finally, the time-domain and frequency-domain characteristics of the motor mover under transient model were obtained when the mover was running stably, thereby obtaining the phase frequency characteristics and amplitude frequency characteristics.

[0118] like Figure 2The diagram shows a cross-sectional view of a linear motor with an internal magnet and an external coil. The coil inside the motor is energized with alternating current, and the stroke of the mover is controlled by adjusting the input voltage. The internal rare-earth permanent magnet has a smaller inner and outer diameter, resulting in lower cost (small size and light weight), easier assembly (lower static magnetic force), and higher efficiency. The higher-order components of the specific thrust experienced by the mover are also lower, making it easier to achieve low vibration in the entire machine.

[0119] Given a motor load (mover mass, stiffness, damping), calculate the current waveform when the mover reaches a specified stroke, and obtain the amplitude and phase corresponding to higher-order frequencies, such as... Figure 3 and Figure 4 .

[0120] Depend on Figure 3 , Figure 4 It can be seen that the current waveform is close to a sine wave. From the frequency domain analysis, the higher-order current components are relatively small, namely:

[0121] First order

[0122] Third order

[0123] Fifth Order

[0124] in, I It is electric current. pi It refers to pi (π), and t is time.

[0125] It can be seen that the higher-order vibration of the refrigeration unit caused by the motor is relatively low. Specifically, at the fifth order, the current amplitude is 0.031A. The passive vibration absorber of the refrigeration unit can cancel out most of the fundamental frequency vibration. Under this model, the Stirling refrigeration unit can achieve very small vibration.

[0126] Comparative Examples of Linear Motor Assembly Structures

[0127] If the magnet is placed externally and the coil is placed internally, that is, the excitation coil is placed inside the magnet, the structural diagram of the linear motor assembly is as follows. Figure 5 As shown. External rare earth permanent magnets have larger inner and outer diameters, resulting in higher costs (larger volume and heavier weight) and making assembly more difficult (due to the larger static magnetic force of the magnets). The efficiency of external and internal magnet motors is similar, and the higher-order components of the specific thrust experienced by the mover are higher, which is not conducive to achieving low vibration in the whole machine.

[0128] Under the same motor load (same mover mass, stiffness, and damping), calculate the current waveform when the mover reaches the same stroke, and obtain the amplitude and phase corresponding to higher-order frequencies, such as... Figure 6 and Figure 7 .

[0129] Depend on Figure 6 and Figure 7As can be seen, the current waveform is quite chaotic. From the frequency domain analysis, the higher-order current components are relatively large, namely...

[0130] First order

[0131] Third order

[0132] Fifth Order

[0133] It is evident that the higher-order vibration of the refrigeration unit caused by the motor is relatively high. Specifically, at the fifth order, the current amplitude is 1.24A. The passive vibration absorber of the refrigeration unit can only offset most of the fundamental frequency vibration and cannot suppress the higher-order frequency vibration. Under this model, the Stirling refrigeration unit as a whole cannot achieve low vibration.

[0134] Example 3

[0135] This embodiment also provides a refrigerator that includes a Stirling refrigerator as described in Embodiment 1 and a controller.

[0136] The controller is configured to perform the following frequency conversion control method to enable the refrigeration unit to operate efficiently and with low vibration:

[0137] The controller applies an initial excitation voltage and excitation frequency (as specified in the design requirements) to the Stirling refrigerator. The excitation voltage range is 0V to 5V, and the excitation frequency range is 40Hz to 120Hz, driving the linear motor inside the Stirling refrigerator to move, and the Stirling refrigerator begins to cool.

[0138] Based on the feedback from the temperature sensor inside the refrigerator, if the temperature inside the refrigerator has not yet reached the target value, the controller will increase the excitation voltage applied to the Stirling refrigerator, that is, increase the input power of the Stirling refrigerator to enhance the cooling.

[0139] The logic of increasing the excitation voltage is to always keep the stroke of the power piston inside the Stirling engine at a set value (the set value can be any number between 1mm and 15mm). The specific method is to collect the power piston stroke signal in real time through a displacement sensor, and adjust the excitation voltage in a closed loop according to the signal feedback so that the stroke of the power piston is always at the set value.

[0140] When the temperature detected by multiple temperature sensors arranged inside the refrigerator reaches the target value, the controller reduces the excitation voltage (i.e., reduces the input power and the stroke of the power piston) until the minimum excitation voltage for maintaining the target temperature inside the refrigerator is reached.

[0141] Keep the temperature inside the refrigerator constant, and adjust the excitation voltage and excitation frequency within a small range (i.e., change the input power) until the minimum input power (and corresponding excitation voltage and excitation frequency) that can maintain the temperature inside the refrigerator constant is found, and maintain this state.

[0142] It should be noted that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one" does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. When referring to performing an action according to an element, it means performing the action at least according to that element, including two cases: performing the action only according to that element, and performing the action according to that element and other elements. Expressions such as "multiple," "repeatedly," and "various" include two, two times, two kinds, and more than two, more than two times, and more than two kinds.

[0143] All documents mentioned in this application are considered to be incorporated in their entirety into the disclosure of this application so that they can serve as a basis for modifications if necessary. Furthermore, it should be understood that after reading the foregoing disclosure of this application, those skilled in the art can make various alterations or modifications to this application, and these equivalent forms also fall within the scope of protection claimed in this application.

Claims

1. A high-power Stirling refrigerator for use in refrigerators, characterized in that, include: Housing assembly, cylinder assembly, piston assembly and linear motor disposed within the housing assembly; The cylinder assembly includes an integral cylinder (32), and the piston assembly includes a power piston mechanism, which includes a power piston (30). The linear motor includes, from the inside to the outside, an inner magnetic yoke (28), a magnetic ring (29), and an outer magnetic yoke (11) in its radial direction. The outer magnetic yoke (11) has a recess facing the magnetic ring (29) for winding a coil (10). A magnetic ring support frame (26) is provided at the lower end of the magnetic ring (29). The magnetic ring support frame (26) is connected to the power piston (30). When the energized coil (10) interacts with the magnetic ring (29), the linear reciprocating motion of the magnetic ring (29) drives the magnetic ring support frame (26) to perform linear reciprocating motion, thereby driving the power piston (30) to perform linear reciprocating motion in the integrated cylinder (32).

2. The Stirling refrigerator as described in claim 1, characterized in that, The power piston mechanism also includes a power leaf spring (24), which is connected to the magnetic ring support frame (26) via a first connector.

3. The Stirling refrigerator as described in claim 2, characterized in that, The power piston (30) is an annular component. The power piston (30) includes a central cavity. The piston assembly also includes a discharge piston mechanism. The discharge piston mechanism includes a first discharge piston (33) and a discharge piston connecting rod (31). In the axial direction of the discharge piston connecting rod (31), the discharge piston connecting rod (31) passes sequentially through the power leaf spring (24), the magnetic ring support frame (26), the central cavity of the power piston (30), and the compression chamber of the Trin refrigerator, and is connected to the first discharge piston (33).

4. The Stirling refrigerator as described in claim 2, characterized in that, The magnetic ring support frame (26) includes a first connecting part (261) and a second connecting part (262). The first connecting part (261) is annular and perpendicular to the second connecting part (262). The first connecting part (261) is connected to the lower end of the magnetic ring (29), and the upper surface of the second connecting part (262) is connected to the lower surface of the power piston (30).

5. The Stirling refrigerator as described in claim 4, characterized in that, The housing assembly is also provided with a motor fixing structure, which includes a soft magnetic fixing frame (13). The upper end face of the soft magnetic fixing frame (13) is connected to the outer magnetic yoke (11), and the lower end face of the soft magnetic fixing frame (13) is connected to the power leaf spring (24).

6. The Stirling refrigerator as described in claim 4, characterized in that, It also includes a cold finger assembly coaxially disposed on the upper end of the housing assembly. The cold finger assembly includes a cold finger base (8) and a hot end heat sink (7). The hot end heat sink (7) is located above the cold finger base (8). The integrated cylinder (32) is connected to the cold finger base (8).

7. The Stirling refrigerator as described in claim 6, characterized in that, The integrated cylinder (32) includes a first cylinder subsection, a second cylinder subsection and a third cylinder subsection. In the radial direction, the first cylinder subsection is located between the power piston (30) and the inner magnetic yoke (28), and the second cylinder subsection is connected to the cold finger base (8).

8. The Stirling refrigerator as described in claim 1, characterized in that, The housing assembly includes a lower housing (9), which includes an annular housing portion (91) and a bottom closed housing portion (92). The Stirling refrigerator also includes a shock-absorbing assembly disposed outside the housing assembly, which includes a shock-absorbing stator fixing screw (15) connected to the bottom closed housing portion (92).

9. A refrigerator, characterized in that, The refrigerator includes a Stirling refrigerator as described in any one of claims 1-8, and the refrigerator includes a controller configured to perform frequency conversion and voltage conversion drive control on the linear motor.

10. A control method for controlling the operation of the refrigerator as described in claim 9, characterized in that, Includes the following steps: The controller drives the linear motor of the Stirling refrigerator to move with a preset initial excitation voltage and excitation frequency, so that the Stirling refrigerator starts up and enters the refrigeration state. If the internal temperature of the refrigerator does not reach the target temperature, the controller is configured to increase the excitation voltage to increase the input power of the Stirling refrigerator. During the process of increasing the excitation voltage, the stroke of the power piston of the Stirling refrigerator is monitored in real time, and the excitation voltage is adjusted in a closed loop so that the stroke of the power piston is always at a set value, which is any value between 1mm and 15mm. Once the temperature inside the refrigerator reaches the target temperature, the controller is configured to reduce the excitation voltage to decrease the input power of the Stirling refrigerator and the stroke of the power piston until the minimum input power required to maintain the target temperature inside the refrigerator is reached. By adjusting the excitation voltage and excitation frequency within a small range, the optimal operating point corresponding to the minimum input power required to maintain the target temperature inside the chamber is found, and operation is maintained at that operating point.

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