Variable frequency ultra-low temperature magnetic suspension heat pump unit

Abstract

This invention belongs to the technical field of heat pump units, specifically a variable frequency ultra-low temperature magnetic levitation heat pump unit, including a heat pump unit body; the compressor of the heat pump unit body adopts a magnetic levitation oil-free compressor; the magnetic levitation oil-free compressor adopts a four-stage compression structure, including a pneumatic part, an electric motor part, a magnetic levitation bearing part, and an embedded controller part; in this invention, the magnetic levitation oil-free technology, four-stage compression, gas injection enthalpy enhancement, and permanent magnet direct drive technology work together to enable the unit to save 30-60% energy, with a motor efficiency ≥96%, maintaining high torque response under wide speed range regulation, a high pressure ratio exceeding 13, no need for electric auxiliary heating at -40℃, and a heating capacity attenuation of less than 15% at -25℃, significantly superior to traditional heat pumps. High-frequency vector variable frequency stepless speed regulation and temperature control accuracy of ±0.1℃ make it suitable for temperature-sensitive scenarios. The entire system is designed to be oil-free, avoiding problems such as oil circuit blockage, emulsification, and oil changes. The design life is 20-30 years, with an average annual failure rate of ≤0.5 times.

Description

Technical Field

[0001] This invention belongs to the field of heat pump unit technology, specifically a variable frequency ultra-low temperature magnetic levitation heat pump unit. Background Technology

[0002] The variable frequency ultra-low temperature magnetic levitation heat pump unit is a cutting-edge technology product in the current HVAC field that integrates high efficiency and energy saving, oil-free stability, and strong heating in extreme cold. It achieves "zero friction" operation of the compressor through magnetic levitation bearings, and combined with variable frequency speed regulation technology, it can accurately adapt to load demand, especially in ultra-low temperature environments of -35℃ or even -40℃, it can still provide stable heating.

[0003] Existing technologies disclose several invention patents in the field of heat pump unit technology. Among them, invention patent CN117739542B discloses a high-efficiency defrosting carbon dioxide heat pump unit, including a motor, a bidirectional lead screw, a sliding block, a defrosting ring, a rubber layer, and nozzles. A motor is fixedly connected to the bottom of each cavity, and the output shaft of each motor is fixedly connected to the bidirectional lead screw. The outer circumference of the bidirectional lead screw is rotatably connected to the sliding block. A defrosting ring is fixedly connected to one side of the sliding block, and a hollow rubber layer is fixedly connected to the inner wall of the defrosting ring. Several nozzles are equidistantly opened on the portion of the rubber layer away from the defrosting ring. This solves the problems of varying frost levels on the evaporator during defrosting, the constant size of the several air outlets on the defrosting ring, and the difficulty in adjusting the distance from the evaporator. It improves the efficiency of defrosting and the heat exchange efficiency of the carbon dioxide heat pump unit. However, this technical solution still has some shortcomings in application. It can interfere with the normal output of the compressor, causing a decrease in its output power. This directly leads to two consequences: firstly, a decrease in the operational stability of the heat pump unit; and secondly, an increase in the overall energy consumption of the system.

[0004] Based on this, the present invention designs a variable frequency ultra-low temperature magnetic levitation heat pump unit to solve the above problems. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, this invention proposes a variable frequency ultra-low temperature magnetic levitation heat pump unit. This invention primarily addresses the issue that evaporator defrosting technology in heat pump units interferes with the normal output of the compressor, causing a decrease in its output power. This directly leads to two consequences: firstly, a decrease in the operational stability of the heat pump unit; and secondly, an increase in the overall energy consumption of the system.

[0006] The technical solution adopted by the present invention to solve its technical problem is: a variable frequency ultra-low temperature magnetic levitation heat pump unit, including a heat pump unit body; the compressor of the heat pump unit body adopts a magnetic levitation oil-free compressor, and a cover is provided around the magnetic levitation oil-free compressor. The top of one side of the cover is connected to an air intake pipe, and the bottom of the other side of the cover is connected to a second return pipe.

[0007] Preferably, the heat pump unit body adopts multiple evaporators, and the air inlet of each evaporator is connected to a ventilation pipe. Two partition plates are snapped into the port of the ventilation pipe, and a rotating ring is rotatably connected between the two partition plates.

[0008] Preferably, the outer ring surface of the rotating ring is connected to a plurality of impeller blades arranged in a ring array, and a connecting shaft is provided at the center of the inner side of the rotating ring. A plurality of mixing blades arranged in a ring array are connected between the connecting shaft and the rotating ring, and the connecting shaft is connected to the outer ring surface of the rotating ring through the plurality of mixing blades.

[0009] Preferably, each of the ventilation pipes has an air inlet pipe connected to the impeller blades inside it on its outer wall. The other ends of the multiple air inlet pipes are connected through a second branch pipe. The multiple air inlet pipes are connected to an external air supply pipe through the second branch pipe. A fan pump is installed on the main body of the heat pump unit. The other end of the air supply pipe is connected to the output end of the fan pump. The input end of the fan pump is connected to the other end of the suction pipe.

[0010] Preferably, each connecting shaft has a first return pipe rotatably connected at its axis, the other ends of the multiple first return pipes are connected through a first branch pipe, and the multiple first return pipes are connected to the other ends of a second return pipe through the first branch pipe.

[0011] Preferably, the air intake pipe is arranged tangentially along the outer wall of the ventilation pipe, and a motor is installed in the other end of the ventilation pipe. The motor body is connected to the other end of the ventilation pipe through a mesh cover. The output shaft of the motor is connected to a sleeve, and a support sleeve is snapped into the other end of the sleeve. A first drive shaft is rotatably connected inside the support sleeve. One end of the first drive shaft is connected to a connecting shaft, and the other end of the first drive shaft has a regular polygonal groove. A second drive shaft is slidably connected in the regular polygonal groove. One end of the second drive shaft is connected to a first spring, and the second drive shaft forms an elastic support with the inner wall of the regular polygonal groove through the second spring. The other end of the second drive shaft is connected to a permanent magnet plate, and an electromagnet is installed on the inner wall of the sleeve corresponding to the permanent magnet plate.

[0012] Preferably, the bottom of the cover has an inner lining groove, and an inner lining sleeve is slidably connected inside the inner lining sleeve. Each of the four circumferential surfaces of the inner lining sleeve has multiple first heat dissipation vents, multiple second heat dissipation vents, and multiple third heat dissipation vents. The multiple first, second, and third heat dissipation vents on a single circumferential surface are arranged alternately. Each second heat dissipation vent has a first filter plate snapped into it, and each third heat dissipation vent has a first sealing plate snapped into it. Adjacent first, second, and third heat dissipation vents form a group. Each of the four circumferential surfaces of the cover has a fourth heat dissipation vent that communicates internally and externally with each group of first heat dissipation vents. The diameters of the first, second, and third heat dissipation vents are interconnected, and the diameter of the fourth heat dissipation vent is smaller than the diameter of the first heat dissipation vent. A second sealing plate is snapped into the bottom port of the inner lining groove. An electric cylinder is installed on the top of the second sealing plate. A double-step plate is connected to the bottom of the inner lining sleeve, and a pusher wheel is slidably connected to the bottom of the inner lining sleeve near the double-step plate. The pusher wheel is installed on the telescopic end of the electric cylinder.

[0013] Preferably, a second filter plate is fixedly sleeved on the outer wall of the sleeve, and the side of the second filter plate opposite to the mixing fins is configured with a curved surface structure.

[0014] Preferably, the magnetic levitation oil-free compressor adopts a four-stage compression structure, including a pneumatic part, an electric motor part, a magnetic levitation bearing part, and an embedded controller part; The pneumatic part is equipped with a dual adjustment mechanism of inlet guide vanes and centrifugal pressurization. By rotating the guide vanes, the air intake flow section and the air intake angle of the first-stage impeller are dynamically adjusted to control the air intake flow rate. The kinetic energy is converted into pressure energy through the high-speed impeller and diffuser. The electric motor section adopts a high-speed permanent magnet synchronous motor with stepless speed regulation of 10000–48000 rpm; The magnetic levitation bearing section includes radial and axial magnetic bearings and a real-time displacement sensing closed-loop control system, which enables the rotor to levitate without contact and reduces the mechanical friction rate. The embedded controller is a multimodal intelligent integrated control unit, including an electrically connected MODBUS communication module, a PLC control system, and a gas injection and enthalpy enhancement system. The MODBUS communication module collects the motor cavity pressure and temperature to intelligently regulate the cooling of the electronic expansion valve. The gas injection and enthalpy enhancement system is located between the two compression stages of the compressor to inject a medium-pressure, low-temperature refrigerant gas to improve the performance of the whole machine under low-temperature / high-pressure ratio conditions.

[0015] Preferably, the heat pump unit adopts high-speed permanent magnet direct drive technology, with a motor efficiency of ≥96% and a speed of ≥60000rpm, and the magnetic levitation oil-free compressor of the heat pump unit has a high pressure ratio of ≥13.

[0016] The beneficial effects of this invention are as follows: 1. In this invention, the synergistic effects of oil-free magnetic levitation, four-stage compression, gas injection enthalpy enhancement, and permanent magnet direct drive technologies enable the unit to save 30-60% energy, achieve a motor efficiency of ≥96%, maintain high torque response under wide speed range regulation, break through the high pressure ratio of 13, eliminate the need for electric auxiliary heating at -40℃, and reduce heating capacity by less than 15% at -25℃, significantly outperforming traditional heat pumps. High-frequency vector frequency conversion provides stepless speed regulation with a temperature control accuracy of ±0.1℃, making it suitable for temperature-sensitive scenarios. The fully oil-free system design avoids problems such as oil circuit blockage, emulsification, and oil changes. It has a design life of 20-30 years and an average annual failure rate of ≤0.5 times. The magnetic levitation bearing achieves contactless levitation, reducing mechanical friction loss to less than 0.2% of traditional compressors. The embedded controller is linked with the PLC to monitor the motor cavity status in real time, intelligently regulate cooling, and improve system adaptability and operational stability.

[0017] 2. In this invention, the hot air inside the casing is circulated back to dissipate heat and preheat the air intake of the evaporator, which reduces the frosting rate, the number of defrosting cycles and energy consumption, and eliminates the need for additional electric heating. At low temperatures, the mixed-flow fins are pneumatically driven, and at high temperatures, the electromagnetic switching to electric drive is achieved, realizing no additional electric drive or high-efficiency motor drive, thus improving environmental adaptability.

[0018] 3. In this invention, the electric cylinder drives the pusher wheel to roll step by step along the double-step plate, realizing the orderly switching of the three steps of "natural cooling → air filtration and replenishment → independent circulation preheating", which improves the waste heat utilization rate and operational reliability. During the air replenishment stage, the first filter plate prevents dust accumulation, and the second filter plate is centrifugally self-cleaning with curved surface, which extends the filter life and reduces airflow resistance. It is suitable for high cleanliness scenarios. The air inlet pipe, impeller blades, adapter ring, mixing fins, electromagnet, permanent magnet plate, motor and connecting shaft and other components are arranged in a coordinated manner to achieve multi-mode adaptive switching in a limited space. Attached Figure Description

[0019] The invention will now be further described with reference to the accompanying drawings.

[0020] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a structural schematic diagram from another perspective of the present invention; Figure 3 This is a schematic diagram of the structure of the invention after disassembly; Figure 4 This is the present invention. Figure 3 A partial structural diagram viewed from above; Figure 5 In this invention Figure 3 A schematic diagram of the cross-sectional structure; Figure 6 This is a schematic diagram of the structure of the magnetic levitation oil-free compressor in this invention; Figure 7 This is the present invention. Figure 6 A structural diagram from another perspective; Figure 8 This is a schematic diagram of the structure of the cover and inner liner in this invention after separation; Figure 9 This is the present invention. Figure 8 A schematic diagram of the three-dimensional structure viewed from below; Figure 10 This is the present invention. Figure 5 Enlarged structural diagram at point A; Figure 11 This is the present invention. Figure 10 Enlarged structural diagram at point B; Figure 12 This is the present invention. Figure 8 Schematic diagram of the inner bushing structure; Figure 13 This is the present invention. Figure 9 Schematic diagram of the inner bushing structure; Figure 14 This is a schematic diagram of the structure of the present invention after removing part of the shell and cover.

[0021] In the diagram: 1. Heat pump unit main body; 2. Magnetic levitation oil-free compressor; 3. Casing; 4. Evaporator; 5. Ventilation duct; 6. Partition plate; 7. Adapter ring; 8. Impeller blades; 9. Connecting shaft; 10. Mixing fins; 11. First return pipe; 12. Second return pipe; 13. Inlet pipe; 14. Gas delivery pipe; 15. Air pump; 16. Suction pipe; 17. Mesh cover; 18. Motor; 19. Sleeve; 20. Support sleeve; 21. First drive shaft; 22. Second drive shaft; 23. First... 24. Spring; 25. Permanent magnet plate; 26. Electromagnet; 27. Inner liner groove; 28. Inner liner sleeve; 29. ​​First heat dissipation port; 20. Second heat dissipation port; 31. Third heat dissipation port; 32. First filter plate; 33. First sealing plate; 34. Second spring; 35. Double-step plate; 36. Pushing wheel; 37. Electric cylinder; 38. Fourth heat dissipation port; 39. Spring groove; 40. First diverter pipe; 41. Second diverter pipe; 42. Regular polygonal groove; 43. Second filter plate; 44. Second sealing plate. Detailed Implementation

[0022] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0023] like Figures 1 to 14 As shown, a variable frequency ultra-low temperature magnetic levitation heat pump unit includes a heat pump unit body 1; the compressor of the heat pump unit body 1 is a magnetic levitation oil-free compressor 2, and a cover 3 is provided around the magnetic levitation oil-free compressor 2. The top of one side of the cover 3 is connected to a suction pipe 16, and the bottom of the other side of the cover 3 is connected to a second return pipe 12. The main body 1 of the heat pump unit adopts multiple evaporators 4. The air inlet of each evaporator 4 is connected to a ventilation pipe 5. Two partition plates 6 are snapped into the port of the ventilation pipe 5, and a rotating ring is rotatably connected between the two partition plates 6. The outer ring surface of the rotating ring is connected to a plurality of impeller blades 8 arranged in a ring array. A connecting shaft 9 is provided at the shaft center on the inner side of the rotating ring. A plurality of mixing blades arranged in a ring array are connected between the connecting shaft 9 and the rotating ring. The connecting shaft 9 is connected to the outer ring surface of the rotating ring through the plurality of mixing blades. Each ventilation pipe 5 has an air inlet pipe 13 connected to the impeller blade 8 inside it on its outer wall. The other ends of multiple air inlet pipes 13 are connected through a second branch pipe 40. Multiple air inlet pipes 13 are connected to an external air supply pipe 14 through the second branch pipe 40. A fan pump 15 is installed on the main body 1 of the heat pump unit. The other end of the air supply pipe 14 is connected to the output end of the fan pump 15. The input end of the fan pump 15 is connected to the other end of the suction pipe 16. Each connecting shaft 9 has a first return pipe 11 rotatably connected at its axis. The other ends of the multiple first return pipes 11 are connected through a first branch pipe 39. The multiple first return pipes 11 are connected to the other end of the second return pipe 12 through the first branch pipe 39.

[0024] In this specific implementation: When the control system of the heat pump unit 1 detects a low ambient temperature, it controls the fan pump 15 to start operating. The fan pump 15 draws hot air from the casing 3 through the suction pipe 16, pressurizes it, and sends it to the second diversion pipe 40 through the air delivery pipe 14. After being diverted by the second diversion pipe 40, the hot air flows into multiple ventilation pipes 5 through multiple intake pipes 13. The hot air flowing into the ventilation pipes 5 passes through multiple mixing fins 10 and converges into the connecting shaft 9. It then flows out through the first return pipe 11 set on the connecting shaft 9. The low-temperature air flowing out of the multiple first return pipes 11 converges through the first diversion pipe 39 and flows to the second return pipe 12, and finally returns to the magnetic levitation oil-free compressor 2, thereby accelerating the heat dissipation speed of the surface of the magnetic levitation oil-free compressor 2. At the same time, during the process of the hot air flowing through the mixing fins 10, it can preheat the ambient air flowing to the evaporator 4, thereby reducing the frosting of the evaporator 4 to a certain extent and achieving energy-saving effect. The hot air inside the casing 3 circulates back to the surface of the magnetic levitation oil-free compressor 2, accelerating its heat dissipation, preventing the compressor from overheating, and ensuring stable operation under low-temperature conditions. When the hot air flows through the mixing fins 10, it preheats the natural air flowing to the evaporator 4, reducing the frosting rate, the number of defrosting cycles, and energy consumption. No additional electric heating is required; the waste heat inside the casing 3 is directly recovered to preheat the air intake of the evaporator 4, reducing the overall energy consumption of the system. Through the orderly arrangement of components such as the diversion pipe, ventilation pipe 5, mixing fins 10, connecting shaft 9, and return pipe, a closed-loop thermal management path is formed without interfering with the original unit structure. The intake pipe 13 is set along the radial direction of the ventilation pipe 5. After the hot air enters the ventilation pipe 5 through the intake pipe 13, it directly acts on the multiple impellers 8 on the outer ring surface of the corresponding transition ring 7. The multiple impellers 8 drive the transition ring 7 to rotate. During the rotation of the transition ring 7, the multiple mixing fins 10 connected to its inner ring surface rotate rapidly, thereby accelerating the flow of natural air to the evaporator 4.

[0025] Specifically, the air intake pipe 13 is arranged tangentially along the outer wall of the ventilation pipe 5. A motor 18 is installed in the other end of the ventilation pipe 5. The motor 18 body is connected to the other end of the ventilation pipe 5 through the mesh cover 17. The output shaft of the motor 18 is connected to a sleeve 19. A support sleeve 20 is snapped into the other end of the sleeve 19. A first drive shaft 21 is rotatably connected in the support sleeve 20. One end of the first drive shaft 21 is connected to the connecting shaft 9. A regular polygonal groove 41 is opened at the other end of the first drive shaft 21. A second drive shaft 22 is slidably connected in the regular polygonal groove 41. A first spring 23 is connected to one end of the second drive shaft 22. The second drive shaft 22 forms an elastic support with the inner wall of the regular polygonal groove 41 through the second spring 33. A permanent magnet plate 24 is connected to the other end of the second drive shaft 22. An electromagnet 25 is installed on the inner wall of the sleeve 19 corresponding to the permanent magnet plate 24.

[0026] In this specific implementation: When the control system of the heat pump unit 1 detects that the ambient temperature is higher than the set threshold, the system controls the air pump to stop working and controls the electromagnet 25 to be energized. After the electromagnet 25 is energized, its end generates magnetism, and the magnetic polarity of the electromagnet 25 and the permanent magnet plate 24 opposite to each other forms a magnetic attraction. Under the action of this magnetic attraction, the permanent magnet plate 24 slides towards the electromagnet 25 in the regular polygonal groove 41 and pulls the first spring 23 to cause elastic deformation. After the permanent magnet plate 24 and the electromagnet 25 achieve magnetic adsorption, the system controls the motor 18 to run. The torque is transmitted to the connecting shaft 9 through the output shaft of the motor 18, and then the motor 18 drives the mixing blades to rotate through the connecting shaft 9, continuing to drive the ambient air to accelerate towards the evaporator 4. In a low-temperature environment, the hot air in the casing 3 drives the impeller 8 and the adapter ring 7 to rotate, and then... The rotating mixed-flow fins 10 accelerate the airflow to the evaporator 4 without additional power, reducing system energy consumption. When the ambient temperature exceeds the threshold, the system automatically stops the air pump and achieves rapid adsorption and positioning through the magnetic attraction between the electromagnet 25 and the permanent magnet plate 24. Then, the system switches to the motor 18 to drive the connecting shaft 9 and the mixed-flow blades, ensuring that the evaporator 4 still has sufficient ventilation in high-temperature environments. After the electromagnet 25 is energized, it generates a reverse magnetic pole attraction with the permanent magnet plate 24. Combined with the elastic deformation and reset mechanism of the first spring 23, a smooth transition of the driving mode is achieved, avoiding mechanical jamming or switching delay. The components such as the air inlet pipe 13, impeller 8, adapter ring 7, mixed-flow fins 10, electromagnet 25, permanent magnet plate 24, regular polygonal groove 41, motor 18, and connecting shaft 9 are arranged in a coordinated manner to achieve adaptive switching between "pneumatic drive" and "electric drive" modes in a limited space, improving the system's environmental adaptability.

[0027] Specifically, the bottom of the cover 3 has an inner lining groove 26, and an inner lining sleeve 27 is slidably connected inside the inner lining sleeve 27. Each of the four circumferential surfaces of the inner lining sleeve 27 has multiple first heat dissipation openings 28, multiple second heat dissipation openings 29, and multiple third heat dissipation openings 30. The multiple first heat dissipation openings 28, multiple second heat dissipation openings 29, and multiple third heat dissipation openings 30 on a single circumferential surface are arranged alternately. Each second heat dissipation opening 29 has a first filter plate 31 snapped into it, and each third heat dissipation opening 30 has a first sealing plate 32 snapped into it. Adjacent first heat dissipation openings 28, second heat dissipation openings 29, and third heat dissipation openings 30 form a single unit. The four sides of the cover 3 are provided with a fourth heat dissipation port 37 that is open to the inside and outside of the first heat dissipation port 28 of each group. The diameters of the first heat dissipation port 28, the second heat dissipation port 29 and the third heat dissipation port 30 are connected. The diameter of the fourth heat dissipation port 37 is smaller than the diameter of the first heat dissipation port 28. A second sealing plate 43 is snapped into the port at the bottom of the inner lining groove 26. An electric cylinder 36 is installed on the top of the second sealing plate 43. A double-step plate 34 is connected to the bottom of the inner lining sleeve 27. A pusher wheel 35 is rolled near the double-step plate 34 at the bottom of the inner lining sleeve 27. The pusher wheel 35 is installed at the telescopic end of the electric cylinder 36.

[0028] In this specific embodiment: When the system controls the air pump to stop working, the first heat dissipation port 28 on the inner bushing 27 and the fourth heat dissipation port 37 on the casing 3 are aligned and connected. Natural air can flow freely through the first heat dissipation port 28 and the fourth heat dissipation port 37 arranged around the magnetic levitation oil-free compressor 2, realizing the natural cooling of the magnetic levitation oil-free compressor 2. When the control system of the heat pump unit 1 detects that the ambient temperature is low, it controls the air pump 15 to start running and first controls the electric cylinder 36 to extend. The extension end of the electric cylinder 36 pushes the pusher wheel 35 to roll towards the double-step plate 34. As the pusher wheel 35 rolls along the slope of the double-step plate 34 to the first step of the double-step plate 34, it generates an upward thrust on the double-step plate 34, thereby pushing the inner bushing 27. The pusher wheel 35 slides upward within the inner lining groove 26. As it rolls on the first level, each group of second heat dissipation vents 29 connects with the corresponding fourth heat dissipation vent 37. The system controls the air pump to operate for a period of time to replenish the air, and the first filter plate 31 filters the air to prevent a large amount of dust from accumulating in the mixing fins 10. After a period of time, the system controls the electric cylinder 36 to continue its extension movement, pushing the pusher wheel 35 to the second level of the double-step plate 34. As the pusher wheel 35 rolls on the second level, each group of third heat dissipation vents 30 connects with the corresponding fourth heat dissipation vent 37, and the first sealing plate 32 seals the connection, thus preventing external air from flowing into the casing 3. This allows the air flowing to the evaporator 4 to be preheated. The independently set flow circulation channel using hot air as the medium improves the utilization rate of waste heat of the magnetic levitation oil-free compressor 2, resulting in good preheating effect. Driven by the electric cylinder 36, the pusher wheel 35 rolls step-by-step along the first and second steps of the double-step plate 34, respectively achieving air replenishment and filtration states for the second heat dissipation port 29 and the fourth heat dissipation port 37, and independent circulation preheating states where the third heat dissipation port 30 and the fourth heat dissipation port 37 are connected and the first sealing plate 32 is blocked. This meets the airflow organization requirements under different operating conditions. When the air pump stops working, the first heat dissipation port 28 and the fourth heat dissipation port 37 are directly aligned, utilizing natural airflow to achieve passive heat dissipation of the magnetic levitation oil-free compressor 2. In low-temperature environments, it switches to an independent circulation preheating channel to avoid cold air interference and improve waste heat utilization. In terms of heat utilization, the air entering the system is filtered through the first filter plate 31 during the air replenishment stage to prevent dust from accumulating inside the mixing fins 10, thus maintaining heat exchange efficiency and system cleanliness. It is particularly suitable for scenarios with high cleanliness requirements, such as electronics, semiconductors, food, and pharmaceuticals. By independently setting up a hot air flow circulation channel, the natural air flowing to the evaporator 4 can fully absorb the waste heat emitted by the magnetic levitation oil-free compressor 2, which not only delays the frosting of the evaporator 4 but also reduces the additional electric heating energy consumption, resulting in significant energy-saving effects. The electric cylinder 36 extends in stages, and the pusher wheel 35 stops at different levels of the double-step plate 34 and cooperates to connect with different heat dissipation ports, realizing the orderly switching of the three steps of "natural cooling → air filtration and replenishment → independent circulation preheating". The process is stable, controllable, and highly reliable.

[0029] Specifically, a second filter plate 42 is fixedly sleeved on the outer wall of the sleeve 19, and the side of the second filter plate 42 facing away from the mixing fins 10 is set with a curved surface structure.

[0030] In this specific embodiment: The second filter plate 42 is used to filter the natural air flowing towards the evaporator 4. The side of the second filter plate 42 facing away from the evaporator 4 is set with a curved surface structure. When the second filter plate 42 is in a rotating state, the centrifugal force generated by its curved surface can cause the dust particles attached to the surface of the filter plate to automatically detach along the tangential direction of the curved surface, thereby achieving an automatic dust removal effect to a certain extent and effectively extending the continuous effective filtration time of the second filter plate 42. During the rotation of the second filter plate 42, the curved surface structure, together with the centrifugal force, can actively throw off the surface dust, significantly reducing the dust adhesion and accumulation rate. There is no need for frequent shutdowns for cleaning or replacement of the filter plate. Through the centrifugal self-cleaning mechanism, the second filter plate 42 can maintain low airflow resistance and high filtration efficiency over a long operating cycle, extending its continuous service life and improving the overall operational stability. The curved surface design utilizes the centrifugal force generated by the rotation of the second filter plate 42 itself, eliminating the need for additional vibration devices or air blowing systems. The structure is simplified and energy-saving, making it particularly suitable for applications with high requirements for air cleanliness, such as electronics, semiconductors, food, and pharmaceuticals, effectively reducing the risk of dust entering the evaporator 4 and its downstream air ducts.

[0031] In this invention, the heat pump unit body 1 adopts a magnetic levitation oil-free compressor 2. This compressor has a four-stage compression structure and integrates a pneumatic part, an electric motor part, a magnetic levitation bearing part, and an embedded controller. All components work together. After startup, the embedded controller is linked with the PLC control system through MODBUS communication to collect pressure and temperature data in the motor chamber 18 and intelligently regulate the electronic expansion valve to achieve precise cooling control. The pneumatic part adopts a dual adjustment mechanism of inlet guide vanes and centrifugal pressurization. The intake flow section and the first-stage impeller intake are dynamically adjusted by rotating the guide vanes. The angle precisely controls the intake flow rate, and then the high-speed impeller enhances the kinetic and pressure energy of the gas. The diffuser efficiently converts the kinetic energy into pressure energy, completing multi-stage stable compression. The motor section uses a high-speed permanent magnet synchronous motor 18, which achieves stepless speed regulation over a wide range of 10,000–48,000 rpm using a high-frequency vector frequency converter driver, with a temperature control accuracy of ±0.1℃. Simultaneously, the heat pump unit body 1 adopts high-speed permanent magnet direct drive technology, with motor 18 achieving an efficiency ≥96% and a speed up to 60,000 rpm. The magnetic levitation bearing section utilizes radial and axial magnetic bearings and real-time positioning... The motion-sensing closed-loop control system allows the rotor to levitate without contact, reducing mechanical friction loss to less than 0.2% of traditional compressors. This magnetic levitation oil-free compressor is compatible with R507A refrigerant and employs compression technology with enthalpy enhancement through gas injection, enabling a high-pressure ratio exceeding 13. It can operate stably without electric auxiliary heating at -40℃ and exhibits less than 15% heat output reduction at -25℃. The entire unit features a fully oil-free design, high efficiency, low energy loss, and wide temperature range operation. Compared to conventional units, it achieves 30-60% energy savings, and the motor efficiency is ≥96%. It maintains high torque response under wide speed range and temperature control accuracy of ±0.1℃, making it suitable for temperature-sensitive scenarios. The oil-free system avoids problems such as oil circuit blockage, emulsification, and oil change maintenance. It has a design life of 20-30 years and an average annual failure rate of ≤0.5 times. The magnetic levitation bearing enables the rotor to levitate without contact, and the mechanical friction loss is less than 0.2% of that of traditional compressors, which greatly reduces energy consumption and wear. The embedded controller is linked with the PLC system to monitor the pressure and temperature of the 18 chambers of the motor in real time and intelligently regulate the cooling of the electronic expansion valve to improve the system's adaptability and operational stability. When the control system of the heat pump unit 1 detects that the ambient temperature is low, it controls the start of the air pump 15. The air pump 15 draws hot air from the casing 3 through the suction pipe 16, pressurizes it, and sends it to the second diversion pipe 40 through the air delivery pipe 14. Then it is diverted to multiple air inlet pipes 13 and flows into the corresponding ventilation pipes 5. The hot air flows through multiple mixing fins 10 and converges to the connecting shaft 9. Then it flows out through the first return pipe 11. The low-temperature air flows through the first diversion pipe 39 and converges to the second return pipe 12. Finally, it flows back to the surface of the magnetic levitation oil-free compressor 2 to accelerate its heat dissipation, prevent overheating, and ensure stable operation under low-temperature conditions. At the same time, during the process of the hot air flowing through the mixing fins 10, it can preheat the ambient air flowing to the evaporator 4, reduce the frost formation on the evaporator 4, and achieve energy-saving effect. The air inlet pipe 13 is arranged radially along the ventilation pipe 5. After the hot air enters the ventilation pipe 5, it directly acts on the multiple impeller blades 8 on the outer ring surface of the transition ring 7, pushing the transition ring 7 to rotate, which in turn drives the multiple mixing fins 10 connected to its inner ring surface to rotate rapidly, causing the natural air to flow towards the evaporator 4 at an accelerated speed. This process does not require additional electricity, thus achieving energy-saving drive. When the ambient temperature exceeds the set threshold, the control system stops the air pump and connects the power supply to the electromagnet 25. The end of the electromagnet 25 generates magnetism with opposite polarity to the opposite side of the permanent magnet plate 24, forming a magnetic attraction. Under this attraction, the permanent magnet plate 24 slides towards the electromagnet 25 in the regular polygonal groove 41, pulling the first spring 23 to undergo elastic deformation. After the permanent magnet plate 24 and the electromagnet 25 are attracted, the system controls the motor 18 to run, transmitting torque to the connecting shaft 9 through the output shaft, driving the mixing blades to rotate, and continuing to guide natural airflow to the evaporator 4. This mechanism realizes a smooth switch between pneumatic and electric drive, avoiding mechanical jamming or delay, and ensuring the ventilation requirements of the evaporator 4 in high-temperature environments. When the system control air pump stops working, the first heat dissipation port 28 on the inner liner 27 is aligned and connected with the fourth heat dissipation port 37 on the cover 3, and natural air flows freely around the magnetic levitation oil-free compressor 2 to achieve natural cooling. When a low-temperature environment is detected, the system starts the air pump 15 and first controls the electric cylinder 36 to extend. The extension end of the electric cylinder 36 pushes the pusher wheel 35 to roll towards the double-step plate 34. When it rolls along the slope to the first step, it generates an upward thrust on the double-step plate 34, pushing the inner liner 27 to slide upward in the inner liner groove 26. During the rolling process in the first step, each group of second heat dissipation ports 29 connects with the corresponding fourth heat dissipation port 37. The system controls the air pump to work for a period of time to complete the air replenishment, and the air is filtered by the first filter plate 31 to prevent dust from accumulating on the mixing fins 10. Subsequently, the electric cylinder 36 continues to extend, pushing the pusher wheel 35 to roll to the second step of the double-step plate 34. At this time, each group of third heat dissipation ports 30 connects with the corresponding fourth heat dissipation port 37 and is sealed by the first sealing plate 32 to prevent external air from flowing into the casing 3. Thus, an independent hot air circulation channel is formed to preheat the air flowing to the evaporator 4, improve the waste heat utilization rate, and achieve good preheating effect. The second filter plate 42 is used to filter the natural air flowing to the evaporator 4. Its side facing away from the evaporator 4 is set as a curved structure. When the second filter plate 42 is in a rotating state, the centrifugal force generated by the curved surface causes the dust particles attached to the surface to automatically detach tangentially, realizing automatic dust removal, significantly extending the continuous effective filtration time, reducing airflow resistance, maintaining high-efficiency filtration performance, and eliminating the need for frequent shutdowns for cleaning or replacement. This structure does not require additional vibration or air blowing devices, simplifying the design and saving energy. It is particularly suitable for high-cleanliness scenarios such as electronics and semiconductors, food and medicine, effectively reducing the risk of dust entering the evaporator 4 and downstream air ducts.

[0032] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A variable frequency ultra-low temperature magnetic levitation heat pump unit, comprising a heat pump unit body; characterized in that: The main compressor of the heat pump unit is a magnetic levitation oil-free compressor. The magnetic levitation oil-free compressor is surrounded by a cover. The top of one side of the cover is connected to an air intake pipe, and the bottom of the other side of the cover is connected to a second return pipe.

2. The variable frequency ultra-low temperature magnetic levitation heat pump unit according to claim 1, characterized in that: The main body of the heat pump unit adopts multiple evaporators. The air inlet of each evaporator is connected to a ventilation pipe. Two partition plates are snapped into the port of the ventilation pipe, and a rotating ring is rotatably connected between the two partition plates.

3. The variable frequency ultra-low temperature magnetic levitation heat pump unit according to claim 2, characterized in that: The outer ring surface of the rotating ring is connected to a plurality of impeller blades arranged in a ring array. A connecting shaft is provided at the center of the inner side of the rotating ring. A plurality of mixing blades arranged in a ring array are connected between the connecting shaft and the rotating ring. The connecting shaft is connected to the outer ring surface of the rotating ring through the plurality of mixing blades.

4. A variable frequency ultra-low temperature magnetic levitation heat pump unit according to claim 3, characterized in that: Each of the ventilation pipes has an air inlet pipe connected to the impeller blades inside it on its outer wall. The other ends of the multiple air inlet pipes are connected through a second branch pipe. The multiple air inlet pipes are connected to an external air supply pipe through the second branch pipe. A fan pump is installed on the main body of the heat pump unit. The other end of the air supply pipe is connected to the output end of the fan pump. The input end of the fan pump is connected to the other end of the suction pipe.

5. A variable frequency ultra-low temperature magnetic levitation heat pump unit according to claim 4, characterized in that: Each connecting shaft has a first return pipe rotatably connected to its axis. The other ends of multiple first return pipes are connected through a first branch pipe. Multiple first return pipes are connected to the other end of a second return pipe through the first branch pipe.

6. A variable frequency ultra-low temperature magnetic levitation heat pump unit according to claim 5, characterized in that: The air intake pipe is arranged tangentially along the outer wall of the ventilation pipe. A motor is installed in the other end of the ventilation pipe. The motor body is connected to the other end of the ventilation pipe through a mesh cover. The output shaft of the motor is connected to a sleeve. A support sleeve is snapped into the other end of the sleeve. A first drive shaft is rotatably connected inside the support sleeve. One end of the first drive shaft is connected to a connecting shaft. The other end of the first drive shaft has a regular polygonal groove. A second drive shaft is slidably connected in the regular polygonal groove. One end of the second drive shaft is connected to a first spring. The second drive shaft forms an elastic support with the inner wall of the regular polygonal groove through the second spring. The other end of the second drive shaft is connected to a permanent magnet plate. An electromagnet is installed on the inner wall of the sleeve corresponding to the permanent magnet plate.

7. A variable frequency ultra-low temperature magnetic levitation heat pump unit according to claim 6, characterized in that: The bottom of the cover has an inner lining groove, and an inner lining sleeve is slidably connected inside the inner lining sleeve. Each of the four circumferential surfaces of the inner lining sleeve has multiple first, second, and third heat dissipation vents. These vents on a single circumferential surface are arranged in an alternating pattern. Each second heat dissipation vent has a first filter plate snapped into it, and each third heat dissipation vent has a first sealing plate snapped into it. Adjacent first, second, and third heat dissipation vents form a group. Each of the four circumferential surfaces of the cover has a fourth heat dissipation vent that communicates internally and externally with each group of first heat dissipation vents. The diameters of the first, second, and third heat dissipation vents are the same, while the diameter of the fourth heat dissipation vent is smaller than that of the first heat dissipation vent. A second sealing plate is snapped into the bottom port of the inner lining groove. An electric cylinder is installed on the top of the second sealing plate. A double-step plate is connected to the bottom of the inner lining sleeve, and a pusher wheel is slidably connected to the bottom of the inner lining sleeve near the double-step plate. The pusher wheel is installed on the telescopic end of the electric cylinder.

8. A variable frequency ultra-low temperature magnetic levitation heat pump unit according to claim 7, characterized in that: The outer wall of the sleeve is fixedly fitted with a second filter plate, and the side of the second filter plate opposite to the mixing fins is set with a curved surface structure.

9. A variable frequency ultra-low temperature magnetic levitation heat pump unit according to claim 1, characterized in that: The magnetic levitation oil-free compressor adopts a four-stage compression structure, including a pneumatic part, an electric motor part, a magnetic levitation bearing part, and an embedded controller part; The pneumatic part is equipped with a dual adjustment mechanism of inlet guide vanes and centrifugal pressurization. By rotating the guide vanes, the air intake flow section and the air intake angle of the first-stage impeller are dynamically adjusted to control the air intake flow rate. The kinetic energy is converted into pressure energy through the high-speed impeller and diffuser. The electric motor section adopts a high-speed permanent magnet synchronous motor with stepless speed regulation of 10000–48000 rpm; The magnetic levitation bearing section includes radial and axial magnetic bearings and a real-time displacement sensing closed-loop control system, which enables the rotor to levitate without contact and reduces the mechanical friction rate. The embedded controller is a multimodal intelligent integrated control unit, including an electrically connected MODBUS communication module, a PLC control system, and a gas injection and enthalpy enhancement system. The MODBUS communication module collects the motor cavity pressure and temperature to intelligently regulate the cooling of the electronic expansion valve. The gas injection and enthalpy enhancement system is located between the two compression stages of the compressor to inject a medium-pressure, low-temperature refrigerant gas to improve the performance of the whole machine under low-temperature / high-pressure ratio conditions.

10. A variable frequency ultra-low temperature magnetic levitation heat pump unit according to claim 1, characterized in that: The main body of the heat pump unit adopts high-speed permanent magnet direct drive technology, with a motor efficiency of ≥96% and a speed of ≥60000rpm. The high pressure ratio of the magnetic levitation oil-free compressor in the main body of the heat pump unit is ≥13.

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