Free piston stirling generator

Abstract

This invention relates to the field of generator technology, and provides a free-piston Stirling generator, comprising a Stirling engine, a linear generator, and a cooling device. The mover of the linear generator is connected to the power output terminal of the Stirling engine, and the cooling device is configured to cool the linear generator. This configuration, using the cooling device to cool the linear generator, can prevent or mitigate the influence of the Stirling engine's temperature on the linear generator's temperature. By increasing the cold-end temperature of the Stirling engine, it can prevent the linear generator's temperature from rising, thus avoiding magnet attenuation and ensuring the linear generator's output performance.

Description

Technical Field

[0001] This invention relates to the field of generator technology, and more particularly to a free piston Stirling generator. Background Technology

[0002] Deep space exploration is a crucial direction for future scientific research, and its key lies in solving the energy and power problems of long-duration flights. Free-piston Stirling generators are simple in structure, with low noise and vibration, high thermoelectric conversion efficiency, strong energy adaptability, long lifespan, and maintenance-free operation, making them suitable for the complex deep-space environment. Due to the unique characteristics of the space environment, energy systems typically dissipate heat through radiators. The area of ​​the radiator is negatively correlated with the fourth power of the temperature; therefore, increasing the cold-end temperature is an effective way to reduce the radiator area. Increasing the cold-end temperature is an inevitable development direction for free-piston Stirling generators to achieve future space applications.

[0003] In existing technology, the linear generator of a free-piston Stirling generator is in direct contact with the cooler. Increasing the cold-end temperature will inevitably cause the temperature of the linear generator to rise. Since the magnets used in free-piston Stirling generators are made of neodymium iron boron material with high coercivity and high magnetic energy product, they will experience magnetic decay at 120℃, which will greatly affect the output performance of the generator.

[0004] Therefore, how to solve the problems of magnet attenuation and generator output performance degradation in existing free piston Stirling generators when the cold end temperature is high has become an important technical problem to be solved by those skilled in the art. Summary of the Invention

[0005] This invention provides a free piston Stirling generator to solve the defects of existing free piston Stirling generators, such as magnet attenuation and reduced generator output performance when the cold end temperature is high.

[0006] The present invention provides a free piston Stirling generator, comprising a Stirling engine, a linear generator, and a cooling device, wherein the mover of the linear generator is connected to the power output end of the Stirling engine, and the cooling device is configured to cool the linear generator.

[0007] According to the present invention, a free piston Stirling generator is provided, wherein the cooling device includes a refrigeration mechanism and a cooling conductor, one end of the cooling conductor is connected to the housing of the linear generator, and the other end is connected to the refrigeration mechanism, and the cooling conductor is configured to transfer the cooling capacity generated by the refrigeration mechanism to the housing of the linear generator.

[0008] According to the present invention, a free piston Stirling generator is provided, wherein the cooling conductor is flexibly connected to the housing of the linear generator, and the cooling conductor is flexibly connected to the refrigeration mechanism.

[0009] According to the present invention, a free piston Stirling generator is provided, wherein the Stirling engine includes a housing with a sealed cavity and a valve piston, a power piston and a temperature regulating assembly disposed in the sealed cavity. The temperature regulating assembly and the linear generator are sequentially disposed inside the housing along a direction from a first end to a second end of the housing, and the mover of the linear generator is connected to the power piston.

[0010] The gas distribution piston divides the sealed cavity into an expansion chamber and a compression chamber. The expansion chamber is connected to the compression chamber through the temperature regulating component. The power piston is slidably disposed in the compression chamber.

[0011] According to the present invention, a free piston Stirling generator is provided, wherein the refrigeration mechanism includes a accumulator, a pulse tube, and a heat exchange section. The first end of the accumulator is connected to the compression chamber through a connecting pipe. The heat exchange section has a heat exchange channel for the flow of the working medium. The two ends of the heat exchange channel are respectively connected to the accumulator and the pulse tube. The heat exchange section is connected to the cooling conductor.

[0012] According to the present invention, a free piston Stirling generator is provided, wherein the refrigeration mechanism further includes a first heat exchanger having a first channel for the working medium to circulate, and the two ends of the first channel are respectively connected to the connecting pipeline and the cold accumulator.

[0013] According to the present invention, a free piston Stirling generator is provided, wherein the refrigeration mechanism further includes a second heat exchanger and an inertial tube. The second heat exchanger has a second channel for the working medium to circulate. The side of the power piston away from the gas distribution piston is formed as a buffer chamber. One end of the second channel is connected to the pulse tube, and the other end is connected to the buffer chamber through the inertial tube.

[0014] According to the present invention, a free piston Stirling generator is provided, wherein the refrigeration mechanism further includes a second heat exchanger, an inertial tube, and a gas chamber. The second heat exchanger has a second channel for the working medium to circulate, one end of the second channel is connected to the pulse tube, and the other end is connected to the gas chamber through the inertial tube.

[0015] According to the present invention, a free piston Stirling generator is provided, wherein the temperature regulation assembly includes a heater, a regenerator and a cooler, the heater, the regenerator and the cooler being arranged sequentially along a direction from a first end to a second end of the housing, and the linear generator being disposed on the side of the cooler away from the regenerator.

[0016] According to the present invention, a free piston Stirling generator is provided, wherein the Stirling engine further includes a first elastic element connected to the housing, and the first elastic element is connected to the valve piston;

[0017] The Stirling engine also includes a second elastic element connected to the housing, and the second elastic element is connected to the power piston.

[0018] The free-piston Stirling generator provided by this invention includes a Stirling engine, a linear generator, and a cooling device. The mover of the linear generator is connected to the power output end of the Stirling engine. The Stirling engine drives the mover of the linear generator to reciprocate relative to the stator of the linear generator to cut magnetic lines of force, thereby enabling the linear generator to output electrical energy. The aforementioned cooling device is used to cool the linear generator, which can prevent or mitigate the influence of the Stirling engine's temperature on the linear generator's temperature. By increasing the cold end temperature of the Stirling engine, the temperature of the linear generator can be prevented from rising, thus preventing the magnets from weakening and ensuring the output performance of the linear generator. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the free piston Stirling generator provided by the present invention. Figure 1 ;

[0021] Figure 2 This is a schematic diagram of the free piston Stirling generator provided by the present invention. Figure 2 .

[0022] Figure label:

[0023] 1: Moving element of linear generator; 2: Cooling conductor; 3: Outer casing; 4: Gas distribution piston; 5: Power piston; 6: Expansion chamber; 7: Compression chamber; 8: Cold accumulator; 9: Pulse tube; 10: Heat exchange section; 11: Connecting pipeline; 12: First heat exchanger; 13: Second heat exchanger; 14: Inertia tube; 15: Buffer chamber; 16: Gas chamber; 17: Heater; 18: Regenerator; 19: Cooler; 20: First elastic element; 21: Second elastic element; 22: Stator of linear generator. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0025] The following is combined with Figures 1 to 2 The present invention describes a free-piston Stirling generator.

[0026] like Figure 1 and Figure 2 As shown, the free piston Stirling generator provided in this embodiment of the invention includes a Stirling engine, a linear generator, and a cooling device. Specifically, the mover 1 of the linear generator is connected to the power output end of the Stirling engine. The Stirling engine drives the mover 1 of the linear generator to reciprocate relative to the stator 22 of the linear generator to cut magnetic lines of force, thereby enabling the linear generator to output electrical energy.

[0027] The aforementioned cooling device is used to cool the linear generator, which can prevent or mitigate the influence of the Stirling engine's temperature on the linear generator's temperature. By increasing the cold end temperature of the Stirling engine, the temperature of the linear generator can be prevented from rising, thus preventing the magnet's magnetic properties from weakening and ensuring the output performance of the linear generator.

[0028] Therefore, the free piston Stirling generator in this embodiment of the invention can operate in a higher temperature range, which is beneficial to promoting the spatial application of the free piston Stirling generator.

[0029] The aforementioned cooling device can be a heat exchanger capable of exchanging heat with a linear generator, using a low-temperature heat exchange medium to exchange heat with the linear generator, thereby cooling the linear generator.

[0030] In this embodiment, the cooling device includes a refrigeration mechanism and a cooling conductor 2. One end of the cooling conductor 2 is connected to the housing of the linear generator, and the other end is connected to the refrigeration mechanism. Specifically, the refrigeration mechanism has a refrigeration section capable of generating cooling capacity. The other end of the cooling conductor 2 is connected to the refrigeration section, so that the cooling conductor 2 transfers the cooling capacity generated by the refrigeration section of the refrigeration mechanism to the housing of the linear generator. After absorbing the cooling capacity, the housing of the linear generator cools down, and then transfers the cooling capacity to the interior of the linear generator, thereby lowering the temperature of the magnets to prevent magnetic attenuation and ensure the output performance of the linear generator.

[0031] The Stirling engine will vibrate during operation. In order to avoid the problem of loosening of the connection between the cooling component 2 and the refrigeration mechanism and the connection between the cooling component 2 and the housing of the linear generator due to vibration, this embodiment makes the cooling component 2 flexibly connected to the refrigeration mechanism and the cooling component 2 flexibly connected to the housing of the linear generator, so as to reduce or avoid the impact of vibration.

[0032] Specifically, the cooling component 2 can be made of a flexible material, which can be, but is not limited to, copper wire bundles.

[0033] When copper wire bundle is selected as the heat-conducting component 2, one end of the copper wire bundle is wound and wrapped around the outside of the linear generator housing, and the other end of the copper wire bundle is wound and wrapped around the outside of the cooling section of the cooling mechanism. As a good conductor of heat, the copper wire bundle can efficiently transfer the cold energy generated by the cooling section of the cooling mechanism to the linear generator.

[0034] It should be noted that the copper wire bundle needs to be in close contact with the cooling part of the cooling mechanism and with the housing of the linear generator to reduce contact thermal resistance.

[0035] The Stirling engine includes a housing 3, a valve train piston 4, a power piston 5, and a temperature control assembly. Specifically, the housing 3 has a sealed cavity inside, and the valve train piston 4, the power piston 5, and the temperature control assembly are disposed inside the sealed cavity of the housing 3. Furthermore, the temperature control assembly and the linear generator are sequentially disposed inside the housing 3 along the direction from the first end to the second end.

[0036] Both the temperature regulating component and the linear generator are provided with a hollow annular structure. The gas distribution piston 4 can reciprocate along the direction from the first end to the second end of the outer shell 3 and extend into the interior of the annular structure of the temperature regulating component, and seal with the temperature regulating component to divide the sealed cavity into an expansion chamber 6 and a compression chamber 7. The expansion chamber 6 is connected to the compression chamber 7 through the temperature regulating component.

[0037] Specifically, the temperature regulation assembly includes a heater 17, a regenerator 18, and a cooler 19, which are arranged sequentially along the direction from the first end to the second end of the housing 3. The linear generator is located on the side of the cooler 19 away from the regenerator 18.

[0038] The heater 17, regenerator 18, and cooler 19 are all configured as annular structures. Airflow channels for the working medium are provided on the heater 17, regenerator 18, and cooler 19, and the expansion chamber 6 is connected to the compression chamber 7 through the airflow channels.

[0039] It should be noted that setting the heater 17, regenerator 18 and cooler 19 as an annular structure can improve the heat exchange efficiency with the working medium.

[0040] The power piston 5 is slidably disposed in the compression chamber 7, specifically extending into the interior of the annular structure of the linear generator and slidingly sealing with the linear generator. Generally, the chamber between the power piston 5 and the valve piston 4 is regarded as the compression chamber 7, and the side of the power piston 5 away from the valve piston 4 is formed as the buffer chamber 15.

[0041] The direction of movement of the power piston 5 relative to the housing 3 is parallel to the direction of movement of the valve piston 4 relative to the housing 3. The direction of movement of the mover 1 of the linear generator relative to the stator 22 of the linear generator is parallel to the direction of movement of the power piston 5 relative to the housing 3, so that the stator 22 of the linear generator is relatively fixed to the housing 3. The mover 1 of the linear generator is connected to the power piston 5. The power piston 5, as the power output end of the Stirling engine, can drive the mover 1 of the linear generator to move back and forth relative to the stator 22 of the linear generator to cut magnetic lines of force, thereby enabling the linear generator to output electrical energy.

[0042] The working medium mentioned above may be, but is not limited to, helium.

[0043] In this embodiment of the invention, the Stirling engine further includes a first elastic element 20 connected to the housing 3, and the valve piston 4 is connected to the first elastic element 20. The first elastic element 20 can adjust and control the displacement of the valve piston 4.

[0044] Specifically, the first elastic element 20 can be a leaf spring, which is disposed in the buffer cavity 15 and its two ends are connected to the outer shell 3. The piston rod of the gas distribution piston 4 passes through the power piston 5 and is connected to the middle of the leaf spring.

[0045] Accordingly, the Stirling engine also includes a second elastic element 21 connected to the housing 3, and the power piston 5 is connected to the second elastic element 21. The second elastic element 21 is configured to adjust and control the displacement of the power piston 5.

[0046] Specifically, the second elastic element 21 can be a leaf spring, which is disposed in the buffer cavity 15 and has both ends connected to the outer shell 3. The piston rod of the power piston 5 is connected to the middle part of the leaf spring.

[0047] The refrigeration mechanism in this embodiment includes a cold accumulator 8, a pulse tube 9, and a heat exchange section 10. Specifically, the first end of the cold accumulator 8 is connected to the compression chamber 7 through a connecting pipe 11. The heat exchange section 10 has a heat exchange channel for the working medium to flow through. The two ends of the heat exchange channel are connected to the cold accumulator 8 and the pulse tube 9, respectively. The heat exchange section 10 is connected to the cooling conductor 2.

[0048] The heat exchange section 10 is made of copper. Copper is a good conductor of heat, which enables the heat exchange section 10 to efficiently transfer the cold energy of the working medium to the cooling component 2.

[0049] It should be noted that the diameter of the connecting pipe 11 should be appropriate and the length should not be too long, so as to lead an appropriate amount of gas from the compression chamber 7 to the accumulator 8. The pulse pipe 9 can be arranged in a straight line with the accumulator 8, or the pulse pipe 9 can be set inside the accumulator 8 and arranged coaxially.

[0050] The aforementioned refrigeration mechanism also includes a first heat exchanger 12 with a first channel. The first heat exchanger 12 includes a copper heat exchange core, and the first channel is disposed within the copper heat exchange core. After the working medium in the compression chamber 7 enters the first channel through the connecting pipe 11, it releases heat to the copper heat exchange core, thereby reducing the temperature of the working medium.

[0051] Copper heat exchange cores can dissipate heat into the outside air. To accelerate the heat dissipation efficiency of copper heat exchange cores, cooling water can be used to cool them down.

[0052] The aforementioned refrigeration mechanism also includes a second heat exchanger 13 and an inertial tube 14. The second heat exchanger 13 has a second channel for the flow of the working medium. The side of the power piston 5 away from the gas distribution piston 4 forms a buffer chamber 15. One end of the second channel is connected to the pulse tube 9, and the other end is connected to the buffer chamber 15 through the inertial tube 14. (Refer to...) Figure 1 .

[0053] In an optional embodiment, the refrigeration mechanism further includes an air chamber 16, such that the other end of the second channel is connected to the air chamber 16 via an inertial tube 14, as shown in the reference. Figure 2 .

[0054] The second heat exchanger 13 includes a copper heat exchange core, and a second channel is disposed inside the copper heat exchange core. When the working medium flows through the copper heat exchange core, it exchanges heat with the copper heat exchange core, releasing heat to the copper heat exchange core, thereby reducing the temperature of the working medium.

[0055] Copper heat exchange cores can dissipate heat into the outside air. To accelerate the heat dissipation efficiency of the heat exchange cores, cooling water can be used to cool them down.

[0056] The inertial tube 14 is a slender tube that can adjust the phase of the mass flow and pressure wave.

[0057] The aforementioned air chamber 16 is a container for storing the working medium. The aforementioned buffer chamber 15 has a sufficiently large volume to provide a constant pressure environment, which is equivalent to the function of the aforementioned air chamber 16.

[0058] The refrigeration principle of the above-mentioned refrigeration mechanism is explained below:

[0059] The reciprocating movement of the gas distribution piston 4 and the power piston 5 generates a high-frequency oscillating pressure wave in the compression chamber 7, providing power for the working medium to flow between the compression chamber 7 and the refrigeration mechanism.

[0060] When the pressure inside the compression chamber 7 increases, the working medium flows through the connecting pipe 11 into the accumulator 8 and the pulse tube 9.

[0061] Before entering the cold storage accumulator 8, the working medium in the compression chamber 7 enters the first heat exchanger 12, where it releases heat to the heat exchange core. The heat is then dissipated to the outside by the heat exchange core, thus reducing the temperature of the working medium.

[0062] The cold accumulator 8 has a cylindrical outer circumference and contains cold storage material inside. After the working medium in the first heat exchanger 12 enters the cold accumulator 8, it can be cooled by the cold storage material, and the temperature of the working medium is further reduced.

[0063] The pulse tube 9 has a cylindrical outer circumference. When the working medium enters the pulse tube 9, the working medium that enters the pulse tube 9 first is compressed by the working medium that enters the pulse tube 9 later, and the temperature of the working medium in the pulse tube 9 gradually rises. When the working medium flows into the heat exchange channel of the second heat exchanger 13, it transfers heat to the second heat exchanger 13 and dissipates it to the outside.

[0064] When the pressure in the compression chamber 7 decreases, the working medium near the second heat exchanger 13 in the pulse tube 9 begins to move towards the other end of the pulse tube 9. Due to the decrease in expansion pressure, the temperature of the working medium gradually decreases. After entering the heat exchange section 10, the cooled working medium transfers its cooling capacity to the heat exchange section 10 and then to the linear generator through the cooling conductor 2, thus lowering the operating temperature of the linear generator. The working medium then enters the cold accumulator 8, where it exchanges heat with the cold storage material, absorbing heat from the cold storage material and causing its temperature to decrease, while the temperature of the working medium increases. The heated working medium then enters the compression chamber 7 after passing through the first heat exchanger 12 and the connecting pipe 11.

[0065] By repeating the above actions, this embodiment can achieve the cooling treatment of the linear generator.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A free-piston Stirling generator, characterized in that, Suitable for operation in higher temperature ranges, the free piston Stirling generator includes a Stirling engine, a linear generator, and a cooling device. The mover of the linear generator is connected to the power output end of the Stirling engine. The pressure wave generated by the Stirling engine drives the cooling device to cool the linear generator. The cooling device is configured to cool the linear generator to prevent the temperature of the Stirling engine from affecting the temperature of the linear generator. When the cold end temperature of the Stirling engine is increased, the temperature of the linear generator is prevented from rising, and the magnetism of the linear generator is prevented from weakening. The cooling device includes a refrigeration mechanism and a cooling conductor. One end of the cooling conductor is connected to the housing of the linear generator, and the other end is connected to the refrigeration mechanism. The cooling conductor is configured to transfer the cooling energy generated by the refrigeration mechanism to the housing of the linear generator. The refrigeration mechanism includes a accumulator, a pulse tube, and a heat exchange section. The first end of the accumulator is connected to the compression chamber of the Stirling engine through a connecting pipe. The heat exchange section has a heat exchange channel for the working medium to flow through. The two ends of the heat exchange channel are respectively connected to the accumulator and the pulse tube. The heat exchange section is connected to the cooling conductor.

2. The free-piston Stirling generator according to claim 1, characterized in that, The cooling conductor is flexibly connected to the housing of the linear generator, and the cooling conductor is flexibly connected to the refrigeration mechanism.

3. The free-piston Stirling generator according to claim 1, characterized in that, The Stirling engine includes a housing with a sealed cavity and a valve piston, a power piston, and a temperature regulating assembly disposed in the sealed cavity. The temperature regulating assembly and the linear generator are sequentially disposed inside the housing along a direction from a first end to a second end. The mover of the linear generator is connected to the power piston. The gas distribution piston divides the sealed cavity into an expansion chamber and a compression chamber. The expansion chamber is connected to the compression chamber through the temperature regulating component. The power piston is slidably disposed in the compression chamber.

4. The free-piston Stirling generator according to claim 3, characterized in that, The refrigeration mechanism further includes a first heat exchanger, which has a first channel for the working medium to flow through, and the two ends of the first channel are respectively connected to the connecting pipeline and the cold accumulator.

5. The free-piston Stirling generator according to claim 3, characterized in that, The refrigeration mechanism further includes a second heat exchanger and an inertial tube. The second heat exchanger has a second channel for the working medium to circulate. The side of the power piston away from the gas distribution piston forms a buffer chamber. One end of the second channel is connected to the pulse tube, and the other end is connected to the buffer chamber through the inertial tube.

6. The free-piston Stirling generator according to claim 3, characterized in that, The refrigeration mechanism further includes a second heat exchanger, an inertial tube, and a gas chamber. The second heat exchanger has a second channel for the working medium to circulate. One end of the second channel is connected to the pulse tube, and the other end is connected to the gas chamber through the inertial tube.

7. The free-piston Stirling generator according to claim 3, characterized in that, The temperature regulating assembly includes a heater, a regenerator, and a cooler, which are arranged sequentially along the direction from the first end to the second end of the housing. The linear generator is located on the side of the cooler away from the regenerator.

8. The free-piston Stirling generator according to claim 3, characterized in that, The Stirling engine also includes a first elastic element connected to the housing, the first elastic element being connected to the valve piston; The Stirling engine also includes a second elastic element connected to the housing, and the second elastic element is connected to the power piston.

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