A muffler shell with adjustable cavity volume, compressor and muffling method

Abstract

This invention provides a noise-reducing housing with adjustable cavity volume, a compressor, and a noise reduction method, relating to the field of compressor noise reduction technology. The noise-reducing housing, compressor, and method of this invention, on the one hand, reduce the volume of the second cavity by setting a first cavity, thereby increasing the cavity modal frequency of the second cavity and preventing the lower peak frequency of the fundamental harmonics from resonating near the cavity modal frequency; on the other hand, a through-hole connects the first and second cavities, and a driving device actuates to close or open the through-hole, thereby changing the cavity volume. Changing the cavity volume alters the cavity modal frequency, thus avoiding cavity resonance within a specific frequency range, ensuring that the compressor has no significant cavity resonance at any speed. Through the combined effect of these two aspects, the cavity resonance noise of the compressor is reduced.

Description

Technical Field

[0001] This invention relates to the field of compressor noise reduction technology, specifically to a noise-reducing housing with adjustable cavity volume, a compressor, and a noise reduction method. Background Technology

[0002] The compressor noise mainly comes from the noise inside the casing and the noise radiated by the vibration of the casing.

[0003] Internal noise includes valve plate slapping noise, refrigerant high-speed flow and ejection noise, structural component friction noise, electromagnetic noise, and structural component vibration noise, among which intake and exhaust valve plate slapping noise and refrigerant high-speed flow and ejection noise in cylinder and cylinder head components account for the highest proportion.

[0004] Because the compressor uses indirect suction, the intake port of the suction muffler is not directly connected to the housing, but rather to the internal cavity of the housing. Valve plate slapping noise, refrigerant high-speed flow and ejection noise, and suction pressure pulsation are transmitted to the internal cavity through the suction muffler. While the suction muffler reduces some noise and pulsation, it still excites a response within the internal cavity. This internal cavity is a closed structure with acoustic modes that vary with its volume and size. The first three modes, located in the 630-1000Hz range, are the main contributors; smaller volumes result in higher frequencies. Under the excitation of noise and pulsation, resonance occurs, amplifying the noise and generating cavity resonance noise.

[0005] The noise and pulsating excitation of a reciprocating piston compressor are both harmonics of the fundamental rotational frequency. Therefore, the harmonics of the fundamental frequency will inevitably cover the entire frequency band across the entire compressor speed range. There will inevitably be excitation peaks near the modal frequencies of the housing cavity, thereby exciting resonance. Therefore, cavity resonance noise is an inherent property of compressor noise and cannot be eliminated. Currently, the only way to reduce noise excitation is to optimize the silencer.

[0006] The noise radiated by the shell vibration comes from the vibration response generated by the vibration of the shell due to the vibration of the mechanism, which radiates outward noise, and from the vibration generated by the acoustic-vibration coupling of the shell due to the noise inside the shell, which radiates outward noise. Summary of the Invention

[0007] The purpose of this invention is to provide a noise-reducing housing with adjustable cavity volume, a compressor, and a noise reduction method, which reduces cavity resonance noise by reducing the cavity volume and adjusting the cavity volume.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] A sound-absorbing housing with adjustable cavity volume includes an upper outer shell, an upper inner shell, a lower shell, a valve assembly, and a drive device;

[0010] The upper inner shell is located inside the upper outer shell, the edge of the upper inner shell is connected to the edge of the upper outer shell, and a first cavity is left between the upper inner shell and the upper outer shell;

[0011] The edge of the upper outer shell and / or the edge of the upper inner shell mates with the edge of the lower shell, and a second cavity is left between the upper inner shell and the lower shell;

[0012] The upper inner shell has at least one through hole, which connects the first cavity and the second cavity;

[0013] The valve assembly is disposed on the upper inner shell, and the driving device is activated to drive the valve assembly to close or open the through hole.

[0014] Preferably, the upper inner shell is provided with a guide channel on one side of the through hole;

[0015] The valve assembly includes a guide rod, a support base, and a sealing gasket. The guide rod is slidably connected within the guide channel, and the support base is provided at one end of the guide rod. The sealing gasket is provided on the support base.

[0016] The driving device drives the guide rod to slide along the guide channel, so that the sealing gasket closes or opens the through hole.

[0017] Preferably, the driving device is an electromagnet, and the movable iron core of the electromagnet is connected to the guide rod.

[0018] Preferably, the side of the sealing gasket that contacts the upper inner shell is provided with sealing protrusions of the same number as the through holes, and the sealing protrusions cooperate with the through holes.

[0019] Preferably, the upper inner shell has several protrusions and recesses on one side of the second cavity.

[0020] Preferably, the outer contours of the protrusion and the recess are stepped.

[0021] Preferably, the edge of the upper inner shell mates with the edge of the upper outer shell, and an annular groove is provided at the edge of the lower shell, with the edge of the upper outer shell fitting into the annular groove.

[0022] A compressor includes a core assembly, a frequency converter, and a controller. The compressor is provided with a noise-absorbing housing with adjustable cavity volume. The core assembly is located inside a second cavity. The controller is connected to the frequency converter and the drive device via signal cables. The controller controls the operation of the drive device according to the output frequency of the frequency converter.

[0023] A compressor noise reduction method, using the compressor described above, wherein the controller stores "the peak frequency of cavity noise generated by the peak excitation of the harmonic peak of the fundamental frequency corresponding to the compressor speed", "the quantitative relationship between the compressor speed and the inverter output frequency" and "the cavity modal frequency of the second cavity".

[0024] The method includes the following steps:

[0025] When the compressor is running, the controller controls the drive device to close the through hole by driving the valve assembly. The controller reads the real-time output frequency of the inverter to obtain the real-time speed of the compressor, and then obtains the "peak frequency of cavity noise generated by the peak excitation of the harmonic peak of the fundamental frequency corresponding to the real-time speed of the compressor".

[0026] When the difference between the peak frequency of cavity noise generated by the peak excitation of the harmonic peak of the real-time rotation speed of the compressor and the cavity modal frequency of the second cavity is less than a set threshold, the controller controls the drive device to operate so as to drive the valve assembly to open the through hole.

[0027] Preferably, the controller also stores "cavity modal frequencies after the first cavity and the second cavity are connected";

[0028] The method further includes the following steps:

[0029] When the difference between the peak frequency of the cavity noise generated by the peak excitation of the harmonic peak of the real-time rotation speed of the compressor and the modal frequency of the cavity after the first cavity and the second cavity are connected is less than a set threshold, the controller controls the drive device to operate so as to drive the valve assembly to close the through hole.

[0030] The beneficial technical effects of this invention are:

[0031] The present invention relates to an adjustable cavity volume silencing housing, compressor, and silencing method. On one hand, by setting a first cavity, the volume of the second cavity is reduced. This reduction in the second cavity volume increases the cavity modal frequency of the second cavity, preventing the fundamental harmonics from resonating near their lower peak frequencies near the cavity modal frequency. On the other hand, a through-hole connects the first and second cavities. An actuating device closes or opens the through-hole, changing the cavity volume. This change alters the cavity modal frequency, avoiding cavity resonance within a specific frequency range, thus preventing significant cavity resonance in the compressor at any speed. The combined effect of these two aspects reduces the compressor's cavity resonance noise. Furthermore, the upper inner shell forms several protrusions and recesses towards the second cavity to achieve refractive silencing. In addition to refractive silencing, sound insulation is further achieved through the upper inner shell and then through the upper outer shell. Thus, by reducing cavity resonance noise, refracting noise reduction, and sound insulation of the inner and outer shells, the compressor achieves a good noise reduction effect. Attached Figure Description

[0032] Figure 1 A cross-sectional view of the compressor according to an embodiment of the present invention. Figure 1 ;

[0033] Figure 2 A cross-sectional view of the compressor according to an embodiment of the present invention. Figure 2 ;

[0034] Figure 3 The explosion of the outer shell, inner shell, valve assembly, and drive device in an embodiment of the present invention. Figure 1 ;

[0035] Figure 4 The explosion of the outer shell, inner shell, valve assembly, and drive device in an embodiment of the present invention. Figure 2 ;

[0036] Figure 5 This is a cross-sectional view of the outer shell, inner shell, valve assembly, and drive device according to an embodiment of the present invention;

[0037] Figure 6 This is a perspective view of the inner shell in an embodiment of the present invention;

[0038] Figure 7 This is a bottom view of the inner shell in an embodiment of the present invention. Detailed Implementation

[0039] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to specific embodiments and the accompanying drawings. Certain embodiments of the invention will be described more fully below with reference to the accompanying drawings, and some, but not all, of these embodiments will be shown. In fact, various embodiments of the invention can be implemented in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided to enable the invention to meet applicable legal requirements.

[0040] In the description of this invention, it should be noted that the terms "inner," "outer," "upper," "lower," "front," and "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0041] In this embodiment of the invention, a noise-reducing housing with adjustable cavity volume, a compressor, and a noise reduction method are provided. Please refer to [reference needed]. Figures 1 to 7 As shown.

[0042] A sound-absorbing housing with adjustable cavity volume includes an upper outer shell 11, an upper inner shell 12, a lower shell 2, a valve assembly 3, and a drive device 4.

[0043] The upper inner shell 12 is located inside the upper outer shell 11, and its edge connects to the edge of the upper outer shell 11. A first cavity 51 is provided between the upper inner shell 12 and the upper outer shell 11. The upper outer shell 11 and the upper inner shell 12 are formed by stamping steel plates using a stamping process. The upper outer shell 11 is thicker than the upper inner shell 12, and the total thickness of the upper outer shell 11 and the upper inner shell 12 is the same as the thickness of the lower shell 2. The external shape and dimensions of the upper outer shell 11 and the lower shell 2 remain unchanged, without affecting the overall height and size of the compressor, achieving compatibility with end product designs (such as refrigerators) and reducing costs.

[0044] The edge of the upper inner shell 12 is interference-fitted with the edge of the upper outer shell 11 to achieve a tight connection between the edges of the upper inner shell 12 and the upper outer shell 11. The edge of the upper inner shell 12 is stacked on the inner wall of the upper outer shell 11, and the outer wall of the edge of the upper outer shell 11 mates with the edge of the lower shell 2. A second cavity 52 is provided between the upper inner shell 12 and the lower shell 2. Specifically, an annular groove 21 is provided at the edge of the lower shell 2, and the edge of the upper outer shell 11 fits into the annular groove 21, thereby assembling and fixing the upper outer shell 11 and the lower shell 2. In this way, the annular groove 21 of the lower shell 2 limits and squeezes the edge of the upper inner shell 12 and the edge of the upper outer shell 11, so that the edge of the upper inner shell 12 and the edge of the upper outer shell 11 are firmly fitted together.

[0045] By setting the first cavity 51, the volume of the second cavity 52 is reduced, the cavity mode frequency of the second cavity 52 is increased, and the lower peak frequency of the fundamental harmonics is prevented from resonating near the cavity mode frequency, thereby reducing cavity resonance noise.

[0046] Compressor speeds are typically 1200-4500 rpm, corresponding to a fundamental frequency of 20-75 Hz. For example, when a compressor runs at 3000 rpm, the fundamental frequency is 50 Hz. There are integer multiples of 50 Hz peaks throughout the entire frequency range, such as 100 Hz, 150 Hz, 200 Hz, and 250 Hz. As the peak frequencies of the fundamental frequency's harmonics increase, their corresponding excitation energy decreases. This allows the higher peak frequencies of the fundamental frequency's harmonics to resonate near the cavity's modal frequency, resulting in lower resonance energy and reduced cavity resonance noise.

[0047] The upper inner shell 12 has two rectangular through holes 61, which connect the first cavity 51 and the second cavity 52.

[0048] A valve assembly 3 and a drive device 4 are provided on the upper inner shell 12. The drive device 4 is activated to drive the valve assembly 3 to close or open the through hole 61.

[0049] Through-hole 61 connects the first cavity 51 and the second cavity 52. ​​The drive device 4 actuates to close or open the through-hole 61, thereby closing or opening the valve assembly 3. When the through-hole 61 is closed, the target cavity is the second cavity 52, the cavity volume decreases, and the cavity modal frequency increases. When the through-hole 61 is open, the target cavity is the cavity formed by connecting the first cavity 51 and the second cavity 52, the cavity volume increases, and the cavity modal frequency decreases. By changing the cavity volume to change the cavity modal frequency, cavity resonance within a specific frequency range is avoided, ensuring that the compressor has no significant cavity resonance at any speed.

[0050] The upper inner shell 12 has a guide channel 62 on one side of the through hole 61. The valve assembly 3 includes a guide rod 31, a support seat 32, and a sealing gasket 33. The guide rod 31 is slidably connected within the guide channel 62. The support seat 32 is located at one end of the guide rod 31, and the sealing gasket 33 is located on the support seat 32. Specifically, the support seat 32 has a rectangular plate structure, and the sealing gasket 33 has a sleeve structure. The mounting hole 331 begins at the middle position of the sealing gasket 33. The guide rod 31 passes through the mounting hole 331, and the sealing gasket 33 wraps around the end face of the support seat 32 facing the upper inner shell 12. In addition, two sealing protrusions 332 are provided on the side of the sealing gasket 33 that contacts the upper inner shell 12. The sealing protrusions 332 cooperate with the through hole 61 to close the through hole 61, thereby improving the sealing performance.

[0051] The driving device 4 drives the guide rod 31 to slide along the guide channel 62, so that the sealing gasket 33 closes or opens the through hole 61. Specifically, the driving device 4 is an electromagnet, and the movable iron core of the electromagnet is connected to the guide rod 31. In this embodiment, the movable iron core of the electromagnet and the guide rod 31 are the same component. After the electromagnet coil is energized, it generates electromagnetic force to drive the movable iron core to move, and the movable iron core (guide rod 31) slides along the guide channel 62. Two screw holes 63 are provided on the upper inner shell 12, and screws 64 pass through the mounting base of the electromagnet and connect to the screw holes 63.

[0052] Currently, the shape of the compressor casing is generally close to that of a sphere, and the outline of the internal cavity is also close to that of a sphere. Various noises generated by the compressor core components and other components first reach the inner surface of the casing when they propagate outward. Since the inner surface is close to a sphere, the sound waves propagating in all directions are incident perpendicularly on the casing, without any effective refraction and noise reduction effect. The noise reduction can only be achieved by the sound insulation effect of the casing.

[0053] In this embodiment, the cavity volume of the anechoic shell is adjustable. The upper inner shell 12 has several protrusions 121 and recesses 122 formed on the side of the second cavity 52. ​​More specifically, the outer contours of the protrusions 121 and recesses 122 are stepped. The protrusions 121 and recesses 122 combine to form multiple angled wedge-like structures. When sound waves are incident on the surfaces of the upper inner shell 12 and the lower shell 2, they are refracted and reflected on the surfaces of the upper inner shell 12 and the lower shell 2. The angled wedge-like structures can refract noise multiple times and gradually attenuate the noise, thereby achieving refraction anechoication and reducing noise.

[0054] A compressor includes a core assembly 7, a frequency converter, and a controller. The compressor is equipped with a noise-absorbing housing with adjustable cavity volume as described above in this embodiment. The core assembly 7 is located inside a second cavity 52. ​​The controller is connected to the frequency converter and the drive device 4 via signal cables 8. The controller controls the operation of the drive device 4 according to the output frequency of the frequency converter.

[0055] A compressor noise reduction method is provided, using the compressor described above in this embodiment. The controller's storage unit stores "the peak frequency of cavity noise generated by the excitation of the harmonic peak of the fundamental frequency corresponding to the compressor's rotational speed", "the quantitative relationship between the compressor's rotational speed and the inverter's output frequency", "the cavity modal frequency of the second cavity 52" and "the cavity modal frequency after the first cavity 51 and the second cavity 52 are connected". The controller reads the real-time output frequency of the inverter to obtain the real-time rotational speed of the compressor, and then obtains "the peak frequency of cavity noise generated by the excitation of the harmonic peak of the fundamental frequency corresponding to the real-time rotational speed of the compressor".

[0056] The method includes the following steps:

[0057] The shape of the compressor's outer shell and the layout of its internal structure determine the internal cavity structure and volume. Given a fixed cavity structure and volume, its acoustic modal frequencies can be determined. The cavity modal frequencies can be accurately obtained through a combination of modal simulation and experimental testing.

[0058] After receiving the signal from the refrigerator's main control board, the compressor inverter controls the compressor to run at a specified speed, and the controller controls the drive device 4 to close the through hole 61.

[0059] By obtaining the compressor cavity modal frequency and the peak frequency of the harmonic of the real-time compressor speed corresponding to the fundamental frequency (i.e., the excitation frequency), the highest peak frequency of cavity noise at different speeds can be obtained. Since the cavity modal frequency is an inherent property and its frequency is constant, the excitation frequency corresponding to the compressor speed is different. When the excitation frequency is close to the cavity modal frequency, resonance amplification noise will be generated. The closer the excitation frequency is, the more obvious the resonance will be. Therefore, the frequency of the most obvious resonance at each speed, i.e., the peak frequency of cavity noise, can be calculated.

[0060] When the difference between the peak frequency of the cavity noise generated by the peak excitation of the harmonic peak of the real-time speed of the compressor corresponding to the fundamental frequency and the cavity modal frequency of the second cavity 52 is less than the set threshold, the controller controls the drive device 4 to operate to drive the valve assembly 3 to open the through hole 61; in this way, the cavity modal frequency of the second cavity 52 is offset from the cavity resonance within a specific frequency range.

[0061] When the difference between the peak frequency of the cavity noise generated by the peak excitation of the harmonics of the fundamental frequency corresponding to the real-time rotational speed of the compressor and the cavity modal frequency after the first cavity 51 and the second cavity 52 are connected is less than a set threshold, the controller controls the drive device 4 to operate, thereby causing the valve assembly 3 to close the through hole 61. In this way, the cavity modal frequencies after the first cavity 51 and the second cavity 52 are staggered to avoid cavity resonance within a specific frequency range.

[0062] The present embodiment has been described in detail above with reference to the accompanying drawings. Based on the above description, those skilled in the art should have a clear understanding of the adjustable cavity volume silencing housing, compressor, and silencing method of the present invention. The adjustable cavity volume silencing housing, compressor, and silencing method of the present invention, on the one hand, by setting a first cavity 51, reduces the volume of the second cavity 52. ​​By reducing the volume of the second cavity 52, the cavity modal frequency of the second cavity 52 is increased, avoiding resonance caused by the lower peak frequency of the fundamental harmonics near the cavity modal frequency of the second cavity 52. ​​On the other hand, the through hole 61 connects the first cavity 51 and the second cavity 52. ​​The driving device 4 actuates to drive the valve assembly 3 to close or open the through hole 61, thereby changing the cavity volume. By changing the cavity volume, the cavity modal frequency is changed, thus avoiding cavity resonance within a specific frequency range, so that the compressor has no obvious cavity resonance at any speed. Through the combined effect of the above two aspects, the cavity resonance noise of the compressor is reduced. Furthermore, the upper inner shell 12 forms several protrusions 121 and recesses 122 on the side facing the second cavity 52 to achieve refraction noise reduction. In addition to refraction noise reduction, sound insulation is further achieved through the upper inner shell 12 and then through the upper outer shell 11. Thus, by reducing cavity resonance noise, refraction noise reduction, and the sound insulation of the upper inner shell 12 and the upper outer shell 11, the compressor achieves a good noise reduction effect.

[0063] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A sound-absorbing shell with adjustable cavity volume, characterized in that: It includes an upper outer shell, an upper inner shell, a lower shell, a valve assembly, and a drive unit; The upper inner shell is located inside the upper outer shell, the edge of the upper inner shell is connected to the edge of the upper outer shell, and a first cavity is left between the upper inner shell and the upper outer shell; The edge of the upper outer shell and / or the edge of the upper inner shell mates with the edge of the lower shell, and a second cavity is provided between the upper inner shell and the lower shell; the compressor core assembly is provided in the second cavity, and the compressor controller is connected to the compressor inverter and the drive device via signal cables; by providing the first cavity, the volume of the second cavity is reduced, and by reducing the volume of the second cavity, the cavity modal frequency of the second cavity is increased; The upper inner shell forms several protrusions and recesses on one side of the second cavity. The protrusions and recesses combine to form a wedge-shaped structure. When sound waves are incident on the surfaces of the upper inner shell and the lower shell, they are refracted and reflected on the surfaces of the upper inner shell and the lower shell to achieve noise reduction. The upper inner shell has at least one through hole, which connects the first cavity and the second cavity; The valve assembly is provided on the upper inner shell. The valve assembly includes a guide rod, a support seat, and a sealing gasket. The controller obtains the real-time speed of the compressor based on the real-time output frequency of the frequency converter, and controls the drive device to operate based on the real-time speed of the compressor, so as to drive the valve assembly to close or open the through hole. By changing the communication state between the second cavity and the first cavity, the cavity volume of the silencer shell is changed, thereby changing the cavity modal frequency. The thickness of the inner shell is less than the thickness of the outer shell.

2. The sound-absorbing housing with adjustable cavity volume according to claim 1, characterized in that: The upper inner shell is provided with a guide channel on one side of the through hole; The valve assembly includes a guide rod, a support base, and a sealing gasket. The guide rod is slidably connected within the guide channel, and the support base is provided at one end of the guide rod. The sealing gasket is provided on the support base. The driving device drives the guide rod to slide along the guide channel, so that the sealing gasket closes or opens the through hole.

3. The sound-absorbing housing with adjustable cavity volume according to claim 2, characterized in that: The driving device is an electromagnet, and the movable iron core of the electromagnet is connected to the guide rod.

4. The sound-absorbing housing with adjustable cavity volume according to claim 2, characterized in that: The side of the sealing gasket that contacts the upper inner shell has sealing protrusions of the same number as the through holes, and the sealing protrusions cooperate with the through holes.

5. The sound-absorbing housing with adjustable cavity volume according to claim 1, characterized in that: The outer contours of the protrusions and the recesses are stepped.

6. The sound-absorbing housing with adjustable cavity volume according to claim 1, characterized in that: The edge of the upper inner shell mates with the edge of the upper outer shell, and an annular groove is provided at the edge of the lower shell, with the edge of the upper outer shell fitting into the annular groove.

7. A compressor, comprising a core assembly, a frequency converter, and a controller, characterized in that: The compressor is equipped with a noise-absorbing housing with adjustable cavity volume as described in any one of claims 1 to 6. The core assembly is located inside the second cavity. The controller is connected to the frequency converter and the drive device via signal cables. The controller obtains the real-time speed of the compressor based on the real-time output frequency of the frequency converter and controls the drive device to operate based on the real-time speed of the compressor, so as to drive the valve assembly to close or open the through hole.

8. A method for silencing a compressor, using the compressor described in claim 7, characterized in that: The controller stores "the peak frequency of cavity noise generated by the peak excitation of the harmonic peak of the fundamental frequency corresponding to the compressor speed", "the quantitative relationship between the compressor speed and the inverter output frequency", "the cavity modal frequency of the second cavity" and "the cavity modal frequency after the first cavity and the second cavity are connected". The method includes the following steps: When the compressor is running, the controller controls the drive device to actuate and drive the valve assembly to close the through hole, so that the target cavity becomes the second cavity; The controller reads the real-time output frequency of the inverter and obtains the real-time speed of the compressor according to the "quantitative relationship between the compressor speed and the inverter output frequency". Then, it obtains the "peak frequency of cavity noise generated by the excitation of the harmonic peak of the fundamental frequency corresponding to the real-time speed of the compressor". The controller compares the "peak frequency of cavity noise generated by the peak excitation of the harmonic peak of the fundamental frequency corresponding to the real-time rotation speed of the compressor" with the "cavity modal frequency of the second cavity" and the "cavity modal frequency after the first cavity and the second cavity are connected" respectively. When the difference between "the peak frequency of cavity noise generated by the peak excitation of the harmonic peak of the fundamental frequency corresponding to the real-time speed of the compressor" and "the cavity modal frequency of the second cavity" is less than a set threshold, the controller controls the drive device to operate to drive the valve assembly to open the through hole and switch the target cavity to the overall cavity after the first cavity and the second cavity are connected; When the difference between "the peak frequency of cavity noise generated by the peak excitation of the harmonic peak of the real-time speed of the compressor corresponding to the fundamental frequency" and "the cavity modal frequency after the first cavity and the second cavity are connected" is less than a set threshold, the controller controls the drive device to operate to drive the valve assembly to close the through hole and switch the target cavity back to the second cavity.

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